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Galinsky R, Bennet L, Gunn AJ. Does MgSO4 protect the preterm brain? Dissecting its role in the pathophysiology of hypoxic ischemic encephalopathy. Neural Regen Res 2024; 19:1861-1862. [PMID: 38227499 DOI: 10.4103/1673-5374.390977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 11/10/2023] [Indexed: 01/17/2024] Open
Affiliation(s)
- Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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Polglase GR, Brian Y, Tantanis D, Blank DA, Badurdeen S, Crossley KJ, Kluckow M, Gill AW, Camm E, Galinsky R, Thomas Songstad N, Klingenberg C, Hooper SB, Roberts CT. Endotracheal epinephrine at standard versus high dose for resuscitation of asystolic newborn lambs. Resuscitation 2024; 198:110191. [PMID: 38522732 DOI: 10.1016/j.resuscitation.2024.110191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 02/21/2024] [Accepted: 03/14/2024] [Indexed: 03/26/2024]
Abstract
INTRODUCTION Endotracheal (ET) epinephrine administration is an option during neonatal resuscitation, if the preferred intravenous (IV) route is unavailable. OBJECTIVES We assessed whether endotracheal epinephrine achieved return of spontaneous circulation (ROSC), and maintained physiological stability after ROSC, at standard and higher dose, in severely asphyxiated newborn lambs. METHODS Near-term fetal lambs were asphyxiated until asystole. Resuscitation was commenced with ventilation and chest compressions. Lambs were randomly allocated to: IV Saline placebo (5 ml/kg), IV Epinephrine (20 micrograms/kg), Standard-dose ET Epinephrine (100 micrograms/kg), and High-dose ET Epinephrine (1 mg/kg). After three allocated treatment doses, rescue IV Epinephrine was administered if ROSC had not occurred. Lambs achieving ROSC were monitored for 60 minutes. Brain histology was assessed for microbleeds. RESULTS ROSC in response to allocated treatment (without rescue IV Epinephrine) occurred in 1/6 Saline, 9/9 IV Epinephrine, 0/9 Standard-dose ET Epinephrine, and 7/9 High-dose ET Epinephrine lambs respectively. Blood pressure during CPR increased after treatment with IV Epinephrine and High-dose ET Epinephrine, but not Saline or Standard-dose ET Epinephrine. After ROSC, both ET Epinephrine groups had lower pH, higher lactate, and higher blood pressure than the IV Epinephrine group. Cortex microbleeds were more frequent in High-dose ET Epinephrine lambs (8/8 lambs examined, versus 3/8 in IV Epinephrine lambs). CONCLUSIONS The currently recommended dose of ET Epinephrine was ineffective in achieving ROSC. Without convincing clinical or preclinical evidence of efficacy, use of ET Epinephrine at this dose may not be appropriate. High-dose ET Epinephrine requires further evaluation before clinical translation.
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Affiliation(s)
- Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Yoveena Brian
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Darcy Tantanis
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Douglas A Blank
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia; Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - Shiraz Badurdeen
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia; Newborn Research Centre, The Royal Women's Hospital, Melbourne, Australia
| | - Kelly J Crossley
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Martin Kluckow
- Department of Neonatology, Royal North Shore Hospital & University of Sydney, Sydney, NSW, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Subiaco, WA, Australia
| | - Emily Camm
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | | | | | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Calum T Roberts
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia; Department of Paediatrics, Monash University, Melbourne, VIC, Australia; Monash Newborn, Monash Children's Hospital, Melbourne, VIC, Australia.
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Shepherd E, Karim T, McIntyre S, Goldsmith S, Keir A, Badawi N, Hunt RW, Galinsky R. Neonatal magnesium sulphate for neuroprotection: A systematic review and meta-analysis. Dev Med Child Neurol 2024. [PMID: 38468452 DOI: 10.1111/dmcn.15899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 02/01/2024] [Accepted: 02/09/2024] [Indexed: 03/13/2024]
Abstract
AIM To review the evidence of the effects of neonatal magnesium sulphate for neuroprotection in perinatal asphyxia and hypoxic-ischaemic encephalopathy (HIE). METHOD This was a systematic review of randomized controlled trials (RCTs) (with meta-analysis) and non-RCTs assessing magnesium sulphate for treating perinatal asphyxia and HIE at 35 weeks or more gestation (primary outcomes: neonatal death and death or long-term major neurodevelopmental disability). RESULTS Twenty-five RCTs (2099 infants) and four non-RCTs (871 infants) were included, 23 in low- and middle-income countries (LMICs). In RCTs, reductions in neonatal death with magnesium sulphate versus placebo or no treatment (risk ratio [RR] = 0.68; 95% confidence interval [CI] = 0.53-0.86; 13 RCTs), and magnesium sulphate with melatonin versus melatonin alone (RR = 0.74; 95% CI = 0.58-0.95; one RCT) were observed. No difference in neonatal death was seen for magnesium sulphate with therapeutic hypothermia versus therapeutic hypothermia alone (RR = 0.66, 95% CI = 0.34-1.26; three RCTs), or magnesium sulphate versus phenobarbital (RR = 3.00; 95% CI = 0.86-10.46; one RCT). No reduction in death or long-term neurodevelopmental disability (RR = 0.52; 95% CI = 0.14-1.89; one RCT) but reductions in several short-term adverse outcomes were observed with magnesium sulphate. Evidence was low- to very-low certainty because of risk of bias and imprecision. INTERPRETATION Given the uncertainty of the current evidence, further robust neonatal magnesium sulphate research is justified. This may include high-quality studies to determine stand-alone effects in LMICs and effects with and after therapeutic hypothermia in high-income countries.
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Affiliation(s)
- Emily Shepherd
- Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Tasneem Karim
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Sarah McIntyre
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Shona Goldsmith
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Amy Keir
- Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia
| | - Nadia Badawi
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- Grace Centre for Newborn Intensive Care, The Children's Hospital, Sydney, New South Wales, Australia
| | - Rod W Hunt
- Cerebral Palsy Alliance Research Institute, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
- Monash Newborn, Monash Children's Hospital, Melbourne, Victoria, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
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Azman Z, Vidinopoulos K, Somers A, Hooper SB, Zahra VA, Thiel AM, Galinsky R, Tran NT, Allison BJ, Polglase GR. In utero ventilation induces lung parenchymal and vascular alterations in extremely preterm fetal sheep. Am J Physiol Lung Cell Mol Physiol 2024; 326:L330-L343. [PMID: 38252635 DOI: 10.1152/ajplung.00249.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 12/19/2023] [Accepted: 01/17/2024] [Indexed: 01/24/2024] Open
Abstract
Extremely preterm infants are often exposed to long durations of mechanical ventilation to facilitate gas exchange, resulting in ventilation-induced lung injury (VILI). New lung protective strategies utilizing noninvasive ventilation or low tidal volumes are now common but have not reduced rates of bronchopulmonary dysplasia. We aimed to determine the effect of 24 h of low tidal volume ventilation on the immature lung by ventilating preterm fetal sheep in utero. Preterm fetal sheep at 110 ± 1(SD) days' gestation underwent sterile surgery for instrumentation with a tracheal loop to enable in utero mechanical ventilation (IUV). At 112 ± 1 days' gestation, fetuses received either in utero mechanical ventilation (IUV, n = 10) targeting 3-5 mL/kg for 24 h, or no ventilation (CONT, n = 9). At necropsy, fetal lungs were collected to assess molecular and histological markers of lung inflammation and injury. IUV significantly increased lung mRNA expression of interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF) compared with CONT, and increased surfactant protein (SP)-A1, SP-B, and SP-C mRNA expression compared with CONT. IUV produced modest structural changes to the airways, including reduced parenchymal collagen and myofibroblast density. IUV increased pulmonary arteriole thickness compared with CONT but did not alter overall elastin or collagen content within the vasculature. In utero ventilation of an extremely preterm lung, even at low tidal volumes, induces lung inflammation and injury to the airways and vasculature. In utero ventilation may be an important model to isolate the confounding mechanisms of VILI to develop effective therapies for preterm infants requiring prolonged respiratory support.NEW & NOTEWORTHY Preterm infants often require prolonged respiratory support, but the relative contribution of ventilation to the development of lung injury is difficult to isolate. In utero mechanical ventilation allows for mechanistic investigations into ventilation-induced lung injury without confounding factors associated with sustaining extremely preterm lambs ex utero. Twenty-four hours of in utero ventilation, even at low tidal volumes, increased lung inflammation and surfactant protein expression and produced structural changes to the lung parenchyma and vasculature.
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Affiliation(s)
- Zahrah Azman
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Kayla Vidinopoulos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Ainsley Somers
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Valerie A Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Alison M Thiel
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Nhi T Tran
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Beth J Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
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Polglase GR, Hwang C, Blank DA, Badurdeen S, Crossley KJ, Kluckow M, Gill AW, Camm E, Galinsky R, Brian Y, Hooper SB, Roberts CT. Assessing the influence of abdominal compression on time to return of circulation during resuscitation of asphyxiated newborn lambs: a randomised preclinical study. Arch Dis Child Fetal Neonatal Ed 2023:fetalneonatal-2023-326047. [PMID: 38123977 DOI: 10.1136/archdischild-2023-326047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 12/06/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVE During neonatal resuscitation, the return of spontaneous circulation (ROSC) can be achieved using epinephrine which optimises coronary perfusion by increasing diastolic pressure. Abdominal compression (AC) applied during resuscitation could potentially increase diastolic pressure and therefore help achieve ROSC. We assessed the use of AC during resuscitation of asystolic newborn lambs, with and without epinephrine. METHODS Near-term fetal lambs were instrumented for physiological monitoring and after delivery, asphyxiated until asystole. Resuscitation was commenced with ventilation followed by chest compressions. Lambs were randomly allocated to: intravenous epinephrine (20 µg/kg, n=9), intravenous epinephrine+continuous AC (n=8), intravenous saline placebo (5 mL/kg, n=6) and intravenous saline+AC (n=9). After three allocated treatment doses, rescue intravenous epinephrine was administered if ROSC had not occurred. Time to achieve ROSC was the primary outcome. Lambs achieving ROSC were ventilated and monitored for 60 min before euthanasia. Brain histology was assessed for micro-haemorrhage. RESULTS Use of AC did not influence mean time to achieve ROSC (epinephrine lambs 177 s vs epinephrine+AC lambs 179 s, saline lambs 602 s vs saline+AC lambs 585 s) or rate of ROSC (nine of nine lambs, eight of eight lambs, one of six lambs and two of eight lambs, respectively). Application of AC was associated with higher diastolic blood pressure (mean value >10 mm Hg), mean and systolic blood pressure and carotid blood flow during resuscitation. Cortex and deep grey matter micro-haemorrhage was more frequent in AC lambs. CONCLUSION Use of AC during resuscitation increased diastolic blood pressure, but did not impact time to ROSC.
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Affiliation(s)
- Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Colin Hwang
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Douglas A Blank
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Paediatrics, Monash University, Clayton, Victoria, Australia
- Monash Newborn, Monash Children's Hospital, Clayton, Victoria, Australia
| | - Shiraz Badurdeen
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Newborn Research Centre, The Royal Women's Hospital, Parkville, Victoria, Australia
| | - Kelly J Crossley
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Martin Kluckow
- Department of Neonatology, Royal North Shore Hospital, St Leonards, New South Wales, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia
| | - Emily Camm
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Yoveena Brian
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Calum T Roberts
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Department of Paediatrics, Monash University, Clayton, Victoria, Australia
- Monash Newborn, Monash Children's Hospital, Clayton, Victoria, Australia
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Vidinopoulos K, Azman Z, Somers A, Zahra VA, Thiel A, Lu H, Pham Y, Tran NT, Allison BJ, Herlenius E, Hooper S, Galinsky R, Polglase GR. Mechanical ventilation induces brainstem inflammation in preterm fetal sheep. Front Pediatr 2023; 11:1225294. [PMID: 37936886 PMCID: PMC10626530 DOI: 10.3389/fped.2023.1225294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 09/25/2023] [Indexed: 11/09/2023] Open
Abstract
Background Preterm infants have immature respiratory drive and often require prolonged periods of mechanical ventilation. Prolonged mechanical ventilation induces systemic inflammation resulting in ventilation-induced brain injury, however its effect on brainstem respiratory centers is unknown. We aimed to determine the effects of 24 h of mechanical ventilation on inflammation and injury in brainstem respiratory centres of preterm fetal sheep. Methods Preterm fetal sheep at 110 ± 1 days (d) gestation were instrumented to provide mechanical ventilation in utero. At 112 ± 1 d gestation, fetuses received either mechanical ventilation (VENT; n = 7; 3 ml/kg) for 24 h, or no ventilation (CONT; n = 6). At post-mortem, fetal brainstems were collected for assessment of mRNA and histological markers of inflammation and injury. Results In utero ventilation (IUV) did not alter any blood-gas parameters. IUV significantly increased systemic IL-6 and IL-8 concentrations over the 24 h period compared to CONT. The number of ameboid microglia within the nucleus tractus solitarius and the raphe nucleus increased in VENT fetuses (p < 0.05 for both vs. control). The % area fraction of GFAP + staining was not significantly higher within the preBötzinger complex (p = 0.067) and retrotrapezoid nucleus and parafacial respiratory group (p = 0.057) in VENT fetuses compared to CONT. Numbers of caspase-3 and TUNEL-positive cells were similar between groups. Gene expression (mRNA) levels of inflammation, injury, cell death and prostaglandin synthesis within the brainstem were similar between groups. Conclusion Mechanical ventilation induces a systemic inflammatory response with only moderate inflammatory effects within the brainstem respiratory centres of preterm fetal sheep.
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Affiliation(s)
- Kayla Vidinopoulos
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Zahrah Azman
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Ainsley Somers
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Valerie A. Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Alison Thiel
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Hui Lu
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Yen Pham
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Nhi Thao Tran
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Beth J. Allison
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Eric Herlenius
- Department of Women’s and Children’s Health, Astrid Lindgren Children’s Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Stuart Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Graeme R. Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
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Kelly SB, Tran NT, Polglase GR, Hunt RW, Nold MF, Nold-Petry CA, Olson DM, Chemtob S, Lodygensky GA, Robertson SA, Gunn AJ, Galinsky R. A systematic review of immune-based interventions for perinatal neuroprotection: closing the gap between animal studies and human trials. J Neuroinflammation 2023; 20:241. [PMID: 37864272 PMCID: PMC10588248 DOI: 10.1186/s12974-023-02911-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 09/28/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND Perinatal infection/inflammation is associated with a high risk for neurological injury and neurodevelopmental impairment after birth. Despite a growing preclinical evidence base, anti-inflammatory interventions have not been established in clinical practice, partly because of the range of potential targets. We therefore systematically reviewed preclinical studies of immunomodulation to improve neurological outcomes in the perinatal brain and assessed their therapeutic potential. METHODS We reviewed relevant studies published from January 2012 to July 2023 using PubMed, Medline (OvidSP) and EMBASE databases. Studies were assessed for risk of bias using the SYRCLE risk of bias assessment tool (PROSPERO; registration number CRD42023395690). RESULTS Forty preclinical publications using 12 models of perinatal neuroinflammation were identified and divided into 59 individual studies. Twenty-seven anti-inflammatory agents in 19 categories were investigated. Forty-five (76%) of 59 studies reported neuroprotection, from all 19 categories of therapeutics. Notably, 10/10 (100%) studies investigating anti-interleukin (IL)-1 therapies reported improved outcome, whereas half of the studies using corticosteroids (5/10; 50%) reported no improvement or worse outcomes with treatment. Most studies (49/59, 83%) did not control core body temperature (a known potential confounder), and 25 of 59 studies (42%) did not report the sex of subjects. Many studies did not clearly state whether they controlled for potential study bias. CONCLUSION Anti-inflammatory therapies are promising candidates for treatment or even prevention of perinatal brain injury. Our analysis highlights key knowledge gaps and opportunities to improve preclinical study design that must be addressed to support clinical translation.
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Affiliation(s)
- Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Nhi T Tran
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Rodney W Hunt
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- Monash Newborn, Monash Children's Hospital, Melbourne, Australia
| | - Marcel F Nold
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- Monash Newborn, Monash Children's Hospital, Melbourne, Australia
| | - Claudia A Nold-Petry
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - David M Olson
- Department of Obstetrics and Gynaecology, University of Alberta, Edmonton, Canada
| | - Sylvain Chemtob
- Department of Paediatrics, CHU Sainte Justine Research Centre, University of Montreal, Quebec, Canada
| | - Gregory A Lodygensky
- Department of Paediatrics, CHU Sainte Justine Research Centre, University of Montreal, Quebec, Canada
| | - Sarah A Robertson
- The University of Adelaide, Robinson Research Institute, North Adelaide, SA, Australia
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, Melbourne, VIC, 3168, Australia.
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia.
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8
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Kelly SB, Dean JM, Zahra VA, Dudink I, Thiel A, Polglase GR, Miller SL, Hooper SB, Bennet L, Gunn AJ, Galinsky R. Progressive inflammation reduces high-frequency EEG activity and cortical dendritic arborisation in late gestation fetal sheep. J Neuroinflammation 2023; 20:124. [PMID: 37226206 DOI: 10.1186/s12974-023-02805-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 05/15/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Antenatal infection/inflammation is associated with disturbances in neuronal connectivity, impaired cortical growth and poor neurodevelopmental outcomes. The pathophysiological substrate that underpins these changes is poorly understood. We tested the hypothesis that progressive inflammation in late gestation fetal sheep would alter cortical neuronal microstructure and neural function assessed using electroencephalogram band power analysis. METHODS Fetal sheep (0.85 of gestation) were surgically instrumented for continuous electroencephalogram (EEG) recording and randomly assigned to repeated saline (control; n = 9) or LPS (0 h = 300 ng, 24 h = 600 ng, 48 h = 1200 ng; n = 8) infusions to induce inflammation. Sheep were euthanised 4 days after the first LPS infusion for assessment of inflammatory gene expression, histopathology and neuronal dendritic morphology in the somatosensory cortex. RESULTS LPS infusions increased delta power between 8 and 50 h, with reduced beta power from 18 to 96 h (P < 0.05 vs. control). Basal dendritic length, numbers of dendritic terminals, dendritic arborisation and numbers of dendritic spines were reduced in LPS-exposed fetuses (P < 0.05 vs. control) within the somatosensory cortex. Numbers of microglia and interleukin (IL)-1β immunoreactivity were increased in LPS-exposed fetuses compared with controls (P < 0.05). There were no differences in total numbers of cortical NeuN + neurons or cortical area between the groups. CONCLUSIONS Exposure to antenatal infection/inflammation was associated with impaired dendritic arborisation, spine number and loss of high-frequency EEG activity, despite normal numbers of neurons, that may contribute to disturbed cortical development and connectivity.
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Affiliation(s)
- Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Justin M Dean
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Valerie A Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
| | - Ingrid Dudink
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Alison Thiel
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright Street, Melbourne, VIC, 3168, Australia.
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia.
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Galinsky R, Dhillon SK, Kelly SB, Wassink G, Davidson JO, Lear CA, van den Heuij LG, Bennet L, Gunn AJ. Magnesium sulphate reduces tertiary gliosis but does not improve EEG recovery or white or grey matter cell survival after asphyxia in preterm fetal sheep. J Physiol 2023; 601:1999-2016. [PMID: 36999348 PMCID: PMC10952359 DOI: 10.1113/jp284381] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 03/09/2023] [Indexed: 04/01/2023] Open
Abstract
Maternal magnesium sulphate (MgSO4 ) treatment is widely recommended before preterm birth for neuroprotection. However, this is controversial because there is limited evidence that MgSO4 provides long-term neuroprotection. Preterm fetal sheep (104 days gestation; term is 147 days) were assigned randomly to receive sham occlusion with saline infusion (n = 6) or i.v. infusion with MgSO4 (n = 7) or vehicle (saline, n = 6) from 24 h before hypoxia-ischaemia induced by umbilical cord occlusion until 24 h after occlusion. Sheep were killed after 21 days of recovery, for fetal brain histology. Functionally, MgSO4 did not improve long-term EEG recovery. Histologically, in the premotor cortex and striatum, MgSO4 infusion attenuated post-occlusion astrocytosis (GFAP+ ) and microgliosis but did not affect numbers of amoeboid microglia or improve neuronal survival. In the periventricular and intragyral white matter, MgSO4 was associated with fewer total (Olig-2+ ) oligodendrocytes compared with vehicle + occlusion. Numbers of mature (CC1+ ) oligodendrocytes were reduced to a similar extent in both occlusion groups compared with sham occlusion. In contrast, MgSO4 was associated with an intermediate improvement in myelin density in the intragyral and periventricular white matter tracts. In conclusion, a clinically comparable dose of MgSO4 was associated with moderate improvements in white and grey matter gliosis and myelin density but did not improve EEG maturation or neuronal or oligodendrocyte survival. KEY POINTS: Magnesium sulphate is widely recommended before preterm birth for neuroprotection; however, there is limited evidence that magnesium sulphate provides long-term neuroprotection. In preterm fetal sheep exposed to hypoxia-ischaemia (HI), MgSO4 was associated with attenuated astrocytosis and microgliosis in the premotor cortex and striatum but did not improve neuronal survival after recovery to term-equivalent age, 21 days after HI. Magnesium sulphate was associated with loss of total oligodendrocytes in the periventricular and intragyral white matter tracts, whereas mature, myelinating oligodendrocytes were reduced to a similar extent in both occlusion groups. In the same regions, MgSO4 was associated with an intermediate improvement in myelin density. Functionally, MgSO4 did not improve long-term recovery of EEG power, frequency or sleep stage cycling. A clinically comparable dose of MgSO4 was associated with moderate improvements in white and grey matter gliosis and myelin density but did not improve EEG maturation or neuronal or oligodendrocyte survival.
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Affiliation(s)
- Robert Galinsky
- Department of PhysiologyUniversity of AucklandAucklandNew Zealand
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityVictoriaAustralia
| | | | - Sharmony B. Kelly
- The Ritchie CentreHudson Institute of Medical ResearchClaytonVictoriaAustralia
- Department of Obstetrics and GynaecologyMonash UniversityVictoriaAustralia
| | - Guido Wassink
- Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | | | | | | | - Laura Bennet
- Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Alistair J. Gunn
- Department of PhysiologyUniversity of AucklandAucklandNew Zealand
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10
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Green EA, Garrick SP, Peterson B, Berger PJ, Galinsky R, Hunt RW, Cho SX, Bourke JE, Nold MF, Nold-Petry CA. The Role of the Interleukin-1 Family in Complications of Prematurity. Int J Mol Sci 2023; 24:ijms24032795. [PMID: 36769133 PMCID: PMC9918069 DOI: 10.3390/ijms24032795] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/20/2023] [Accepted: 01/22/2023] [Indexed: 02/05/2023] Open
Abstract
Preterm birth is a major contributor to neonatal morbidity and mortality. Complications of prematurity such as bronchopulmonary dysplasia (BPD, affecting the lung), pulmonary hypertension associated with BPD (BPD-PH, heart), white matter injury (WMI, brain), retinopathy of prematurity (ROP, eyes), necrotizing enterocolitis (NEC, gut) and sepsis are among the major causes of long-term morbidity in infants born prematurely. Though the origins are multifactorial, inflammation and in particular the imbalance of pro- and anti-inflammatory mediators is now recognized as a key driver of the pathophysiology underlying these illnesses. Here, we review the involvement of the interleukin (IL)-1 family in perinatal inflammation and its clinical implications, with a focus on the potential of these cytokines as therapeutic targets for the development of safe and effective treatments for early life inflammatory diseases.
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Affiliation(s)
- Elys A. Green
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC 3168, Australia
| | - Steven P. Garrick
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
| | - Briana Peterson
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
| | - Philip J. Berger
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
| | - Robert Galinsky
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC 3168, Australia
| | - Rod W. Hunt
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC 3168, Australia
| | - Steven X. Cho
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
| | - Jane E. Bourke
- Department of Pharmacology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC 3168, Australia
| | - Marcel F. Nold
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC 3168, Australia
| | - Claudia A. Nold-Petry
- Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC 3168, Australia
- Department of Paediatrics, Monash University, Melbourne, VIC 3168, Australia
- Correspondence:
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11
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Galinsky R, Kelly S, Green E, Hunt R, Nold-Petry C, Gunn A, Nold M. Interleukin-1: an important target for perinatal neuroprotection? Neural Regen Res 2023; 18:47-50. [PMID: 35799507 PMCID: PMC9241389 DOI: 10.4103/1673-5374.341044] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Perinatal inflammation is a significant risk factor for lifelong neurodevelopmental impairments such as cerebral palsy. Extensive clinical and preclinical evidence links the severity and pattern of perinatal inflammation to impaired maturation of white and grey matters and reduced brain growth. Multiple pathways are involved in the pathogenesis of perinatal inflammation. However, studies of human and experimental perinatal encephalopathy have demonstrated a strong causative link between perinatal encephalopathy and excessive production of the pro-inflammatory effector cytokine interleukin-1. In this review, we summarize clinical and preclinical evidence that underpins interleukin-1 as a critical factor in initiating and perpatuating systemic and central nervous system inflammation and subsequent perinatal brain injury. We also highlight the important role of endogenous interleukin-1 receptor antagonist in mitigating interleukin-1-driven neuroinflammation and tissue damage, and summarize outcomes from clinical and mechanistic animal studies that establish the commercially available interleukin-1 receptor antagonist, anakinra, as a safe and effective therapeutic intervention. We reflect on the evidence supporting clinical translation of interleukin-1 receptor antagonist for infants at the greatest risk of perinatal inflammation and impaired neurodevelopment, and suggest a path to advance interleukin-1 receptor antagonist along the translational path for perinatal neuroprotection.
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12
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Green EA, Metz D, Galinsky R, Atkinson R, Skuza EM, Clark M, Gunn AJ, Kirkpatrick CM, Hunt RW, Berger PJ, Nold-Petry CA, Nold MF. Anakinra Pilot - a clinical trial to demonstrate safety, feasibility and pharmacokinetics of interleukin 1 receptor antagonist in preterm infants. Front Immunol 2022; 13:1022104. [PMID: 36389766 PMCID: PMC9647081 DOI: 10.3389/fimmu.2022.1022104] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 10/10/2022] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Bronchopulmonary dysplasia (BPD), its complication pulmonary hypertension (BPD-PH) and preterm brain and gut injury lead to significant morbidity and mortality in infants born extremely prematurely. There is extensive evidence that the pro-inflammatory cytokine interleukin 1 (IL-1) plays a key role in the pathophysiology of these illnesses. Two decades of clinical use in paediatric and adult medicine have established an excellent safety and efficacy record for IL-1 blockade with IL-1 receptor antagonist (IL-1Ra, medication name anakinra). Building on robust pre-clinical evidence, the Anakinra Pilot trial aims to demonstrate safety and feasibility of administering anakinra to preterm infants, and to establish pharmacokinetics in this population. Its ultimate goal is to facilitate large studies that will test whether anakinra can ameliorate early-life inflammation, thus alleviating multiple complications of prematurity. METHODS AND ANALYSIS Anakinra Pilot is an investigator-initiated, single arm, safety and feasibility dose-escalation trial in extremely preterm infants born between 24 weeks 0 days (240) and 276 weeks of gestational age (GA). Enrolled infants will receive anakinra intravenously over the first 21 days after birth, starting in the first 24 h after birth. In the first phase, dosing is 1 mg/kg every 48 h, and dosage will increase to 1.5 mg/kg every 24 h in the second phase. Initial anakinra dosing was determined through population pharmacokinetic model simulations. During the study, there will be a interim analysis to confirm predictions before undertaking dose assessment. Anakinra therapy will be considered safe if the frequency of adverse outcomes/events does not exceed that expected in infants born at 240-276 weeks GA. CLINICAL TRIAL REGISTRATION https://clinicaltrials.gov/, identifier NCT05280340.
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Affiliation(s)
- Elys A. Green
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC, Australia
| | - David Metz
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- Monash Children’s Hospital, Melbourne, VIC, Australia
- Murdoch Children’s Research Institute, Melbourne, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Rebecka Atkinson
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC, Australia
| | - Elizbeth M. Skuza
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Megan Clark
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC, Australia
- Faculty of Pharmacy and Pharmaceutical Science, Monash University, Melbourne, VIC, Australia
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Carl M. Kirkpatrick
- Monash Institute for Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Rod W. Hunt
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC, Australia
| | - Philip J. Berger
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Claudia A. Nold-Petry
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Marcel F. Nold
- Department of Paediatrics, Monash University, Melbourne, VIC, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Monash Newborn, Monash Children’s Hospital, Melbourne, VIC, Australia
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13
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Schmölzer GM, Roberts CT, Blank DA, Badurdeen S, Miller SL, Crossley KJ, Stojanovska V, Galinsky R, Kluckow M, Gill AW, Hooper SB, Polglase GR. Single versus continuous sustained inflations during chest compressions and physiological-based cord clamping in asystolic lambs. Arch Dis Child Fetal Neonatal Ed 2022; 107:488-494. [PMID: 34844983 PMCID: PMC9411918 DOI: 10.1136/archdischild-2021-322881] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/03/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND The feasibility and benefits of continuous sustained inflations (SIs) during chest compressions (CCs) during delayed cord clamping (physiological-based cord clamping; PBCC) are not known. We aimed to determine whether continuous SIs during CCs would reduce the time to return of spontaneous circulation (ROSC) and improve post-asphyxial blood pressures and flows in asystolic newborn lambs. METHODS Fetal sheep were surgically instrumented immediately prior to delivery at ~139 days' gestation and asphyxia induced until lambs reached asystole. Lambs were randomised to either immediate cord clamping (ICC) or PBCC. Lambs then received a single SI (SIsing; 30 s at 30 cmH2O) followed by intermittent positive pressure ventilation, or continuous SIs (SIcont: 30 s duration with 1 s break). We thus examined 4 groups: ICC +SIsing, ICC +SIcont, PBCC +SIsing, and PBCC +SIcont. Chest compressions and epinephrine administration followed international guidelines. PBCC lambs underwent cord clamping 10 min after ROSC. Physiological and oxygenation variables were measured throughout. RESULTS The time taken to achieve ROSC was not different between groups (mean (SD) 4.3±2.9 min). Mean and diastolic blood pressure was higher during chest compressions in PBCC lambs compared with ICC lambs, but no effect of SIs was observed. SIcont significantly reduced pulmonary blood flow, diastolic blood pressure and oxygenation after ROSC compared with SIsing. CONCLUSION We found no significant benefit of SIcont over SIsing during CPR on the time to ROSC or on post-ROSC haemodynamics, but did demonstrate the feasibility of continuous SIs during advanced CPR on an intact umbilical cord. Longer-term studies are recommended before this technique is used routinely in clinical practice.
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Affiliation(s)
| | - Calum T Roberts
- Department of Paediatrics, Monash University Faculty of Medicine Nursing and Health Sciences, Clayton, Victoria, Australia
| | - Douglas A Blank
- Monash Newborn, Monash Health, Clayton, Victoria, Australia
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Shiraz Badurdeen
- Newborn Research Centre, Royal Women's Hospital, Parkville, Victoria, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Monash University, Clayton, Victoria, Australia
| | - Kelly J Crossley
- Hudson Institute of Medical Research, Ritchie Centre, Monash University, Melbourne, Victoria, Australia
| | | | - Robert Galinsky
- The Ritchie Centre, Monash University, Clayton, Victoria, Australia
| | - Martin Kluckow
- Department of Neonatology, St Leonards, New South Wales, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
- Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Graeme R Polglase
- Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
- Hudson Institute of Medical Research, Clayton, Victoria, Australia
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14
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Chan KYY, Tran NT, Papagianis PC, Zahra VA, Nitsos I, Moxham AM, LaRosa DA, McDonald C, Miller SL, Galinsky R, Alahmari DM, Stojanovska V, Polglase GR. Investigating Pathways of Ventilation Induced Brain Injury on Cerebral White Matter Inflammation and Injury After 24 h in Preterm Lambs. Front Physiol 2022; 13:904144. [PMID: 35860659 PMCID: PMC9289398 DOI: 10.3389/fphys.2022.904144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
Initiation of respiratory support in the delivery room increases the risk and severity of brain injury in preterm neonates through two major pathways: an inflammatory pathway and a haemodynamic pathway. The relative contribution of each pathway on preterm brain injury is not known. We aimed to assess the role of the inflammatory and haemodynamic pathway on ventilation-induced brain injury (VIBI) in the preterm lamb. Fetal lambs (125 ± 1 day gestation) were exteriorised, instrumented and ventilated with a high tidal-volume (VT) injurious strategy for 15 min either with placental circulation intact to induce the inflammatory pathway only (INJINF; n = 7) or umbilical cord occluded to induce both the inflammatory and haemodynamic pathways (INJINF+HAE; n = 7). Sham controls were exteriorised but not ventilated (SHAM; n = 5) while unoperated controls (UNOP; n = 7) did not undergo fetal instrumentation. Fetuses were returned in utero following intervention and the ewe allowed to recover. Arterial blood gases and plasma were sampled periodically. Twenty-four hours following intervention, lambs were delivered and maintained on non-injurious ventilation for ∼40 min then brains were collected post-mortem for immunohistochemistry and RT-qPCR to assess inflammation, vascular pathology and cell death within white matter regions. Compared to INJINF lambs, INJINF+HAE lambs achieved a consistently higher VT during injurious ventilation and carotid blood flow was significantly lower than baseline by the end of ventilation. Throughout the 24 h recovery period, systemic arterial IL-6 levels of INJINF+HAE lambs were significantly higher than SHAM while there was no difference between INJINF and SHAM animals. At 24 h, mRNA expression levels of pro-inflammatory cytokines, tight junction proteins, markers of cell death, and histological injury indices of gliosis, blood vessel protein extravasation, oligodendrocyte injury and cell death were not different between groups. Injurious ventilation, irrespective of strategy, did not increase brain inflammation or injury 24 h later when compared to control animals. However, the haemodynamic pathway did influence carotid blood flow adaptations during injurious ventilation and increased systemic arterial IL-6 that may underlie long-term pathology. Future studies are required to further characterise the pathways and their long-term effects on VIBI.
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Affiliation(s)
- Kyra YY Chan
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Nhi T. Tran
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Paris C. Papagianis
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Valerie A. Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Alison M. Moxham
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Domenic A. LaRosa
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Courtney McDonald
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Suzanne L. Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Dhafer M. Alahmari
- Monash Biomedicine Discovery Institute and Department of Medical Imaging and Radiation Sciences, Monash University, Clayton, VIC, Australia
- Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia
- Department of Diagnostic Imaging, King Saud Medical City, Riyadh, Saudi Arabia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Graeme R. Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
- *Correspondence: Graeme R. Polglase,
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15
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Stojanovska V, Atta J, Kelly SB, Zahra VA, Matthews-Staindl E, Nitsos I, Moxham A, Pham Y, Hooper SB, Herlenius E, Galinsky R, Polglase GR. Increased Prostaglandin E2 in Brainstem Respiratory Centers Is Associated With Inhibition of Breathing Movements in Fetal Sheep Exposed to Progressive Systemic Inflammation. Front Physiol 2022; 13:841229. [PMID: 35309054 PMCID: PMC8928579 DOI: 10.3389/fphys.2022.841229] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/08/2022] [Indexed: 12/11/2022] Open
Abstract
Background Preterm newborns commonly experience apnoeas after birth and require respiratory stimulants and support. Antenatal inflammation is a common antecedent of preterm birth and inflammatory mediators, particularly prostaglandin E2 (PGE2), are associated with inhibition of vital brainstem respiratory centers. In this study, we tested the hypothesis that exposure to antenatal inflammation inhibits fetal breathing movements (FBMs) and increases inflammation and PGE2 levels in brainstem respiratory centers, cerebrospinal fluid (CSF) and blood plasma. Methods Chronically instrumented late preterm fetal sheep at 0.85 of gestation were randomly assigned to receive repeated intravenous saline (n = 8) or lipopolysaccharide (LPS) infusions (experimental day 1 = 300 ng, day 2 = 600 ng, day 3 = 1200 ng, n = 8). Fetal breathing movements were recorded throughout the experimental period. Sheep were euthanized 4 days after starting infusions for assessment of brainstem respiratory center histology. Results LPS infusions increased circulating and cerebrospinal fluid PGE2 levels, decreased arterial oxygen saturation, increased the partial pressure of carbon dioxide and lactate concentration, and decreased pH (p < 0.05 for all) compared to controls. LPS infusions caused transient reductions in the % of time fetuses spent breathing and the proportion of vigorous fetal breathing movements (P < 0.05 vs. control). LPS-exposure increased PGE2 expression in the RTN/pFRG (P < 0.05 vs. control) but not the pBÖTC (P < 0.07 vs. control) of the brainstem. No significant changes in gene expression were observed for PGE2 enzymes or caspase 3. LPS-exposure reduced the numbers of GFAP-immunoreactive astrocytes in the RTN/pFRG, NTS and XII of the brainstem (P < 0.05 vs. control for all) and increased microglial activation in the RTN/pFRG, preBÖTC, NTS, and XII brainstem respiratory centers (P < 0.05 vs. control for all). Conclusion Chronic LPS-exposure in late preterm fetal sheep increased PGE2 levels within the brainstem, CSF and plasma, and was associated with inhibition of FBMs, astrocyte loss and microglial activation within the brainstem respiratory centers. Further studies are needed to determine whether the inflammation-induced increase in PGE2 levels plays a key role in depressing respiratory drive in the perinatal period.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - John Atta
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Sharmony B. Kelly
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Valerie A. Zahra
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Eva Matthews-Staindl
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Alison Moxham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Yen Pham
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
| | - Stuart B. Hooper
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Eric Herlenius
- Department of Women’s and Children’s Health, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
- Astrid Lindgren Childrens Hospital, Karolinska University Hospital, Stockholm, Sweden
| | - Robert Galinsky
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- *Correspondence: Robert Galinsky,
| | - Graeme R. Polglase
- The Ritchie Center, Hudson Institute of Medical Research, Melbourne, VIC, Australia
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
- Graeme R. Polglase,
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Tran NT, Kelly SB, Snow RJ, Walker DW, Ellery SJ, Galinsky R. Assessing Creatine Supplementation for Neuroprotection against Perinatal Hypoxic-Ischaemic Encephalopathy: A Systematic Review of Perinatal and Adult Pre-Clinical Studies. Cells 2021; 10:cells10112902. [PMID: 34831126 PMCID: PMC8616304 DOI: 10.3390/cells10112902] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/09/2022] Open
Abstract
There is an important unmet need to develop interventions that improve outcomes of hypoxic-ischaemic encephalopathy (HIE). Creatine has emerged as a promising neuroprotective agent. Our objective was to systematically evaluate the preclinical animal studies that used creatine for perinatal neuroprotection, and to identify knowledge gaps that need to be addressed before creatine can be considered for pragmatic clinical trials for HIE. Methods: We reviewed preclinical studies up to 20 September 2021 using PubMed, EMBASE and OVID MEDLINE databases. The SYRCLE risk of bias assessment tool was utilized. Results: Seventeen studies were identified. Dietary creatine was the most common administration route. Cerebral creatine loading was age-dependent with near term/term-equivalent studies reporting higher increases in creatine/phosphocreatine compared to adolescent-adult equivalent studies. Most studies did not control for sex, study long-term histological and functional outcomes, or test creatine post-HI. None of the perinatal studies that suggested benefit directly controlled core body temperature (a known confounder) and many did not clearly state controlling for potential study bias. Conclusion: Creatine is a promising neuroprotective intervention for HIE. However, this systematic review reveals key knowledge gaps and improvements to preclinical studies that must be addressed before creatine can be trailed for neuroprotection of the human fetus/neonate.
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Affiliation(s)
- Nhi Thao Tran
- School of Health & Biomedical Sciences, STEM College, RMIT University, Melbourne 3083, Australia; (N.T.T.); (D.W.W.)
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne 3168, Australia; (S.B.K.); (S.J.E.)
| | - Sharmony B. Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne 3168, Australia; (S.B.K.); (S.J.E.)
- Department of Obstetrics & Gynecology, Monash University, Melbourne 3168, Australia
| | - Rod J. Snow
- Institute for Physical Activity & Nutrition, Deakin University, Melbourne 3125, Australia;
| | - David W. Walker
- School of Health & Biomedical Sciences, STEM College, RMIT University, Melbourne 3083, Australia; (N.T.T.); (D.W.W.)
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne 3168, Australia; (S.B.K.); (S.J.E.)
| | - Stacey J. Ellery
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne 3168, Australia; (S.B.K.); (S.J.E.)
- Department of Obstetrics & Gynecology, Monash University, Melbourne 3168, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne 3168, Australia; (S.B.K.); (S.J.E.)
- Department of Obstetrics & Gynecology, Monash University, Melbourne 3168, Australia
- Correspondence:
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17
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Kelly SB, Stojanovska V, Zahra VA, Moxham A, Miller SL, Moss TJM, Hooper SB, Nold MF, Nold-Petry CA, Dean JM, Bennet L, Polglase GR, Gunn AJ, Galinsky R. Interleukin-1 blockade attenuates white matter inflammation and oligodendrocyte loss after progressive systemic lipopolysaccharide exposure in near-term fetal sheep. J Neuroinflammation 2021; 18:189. [PMID: 34465372 PMCID: PMC8408978 DOI: 10.1186/s12974-021-02238-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 08/11/2021] [Indexed: 12/14/2022] Open
Abstract
Background Increased systemic and tissue levels of interleukin (IL)-1β are associated with greater risk of impaired neurodevelopment after birth. In this study, we tested the hypothesis that systemic IL-1 receptor antagonist (Ra) administration would attenuate brain inflammation and injury in near-term fetal sheep exposed to lipopolysaccharide (LPS). Methods Chronically instrumented near-term fetal sheep at 0.85 of gestation were randomly assigned to saline infusion (control, n = 9), repeated LPS infusions (0 h = 300 ng, 24 h = 600 ng, 48 h = 1200 ng, n = 8) or repeated LPS plus IL-1Ra infusions (13 mg/kg infused over 4 h) started 1 h after each LPS infusion (n = 9). Sheep were euthanized 4 days after starting infusions for histology. Results LPS infusions increased circulating cytokines and were associated with electroencephalogram (EEG) suppression with transiently reduced mean arterial blood pressure, and increased carotid artery perfusion and fetal heart rate (P < 0.05 vs. control for all). In the periventricular and intragyral white matter, LPS-exposure increased IL-1β immunoreactivity, numbers of caspase 3+ cells and microglia, reduced astrocyte and olig-2+ oligodendrocyte survival but did not change numbers of mature CC1+ oligodendrocytes, myelin expression or numbers of neurons in the cortex and subcortical regions. IL-1Ra infusions reduced circulating cytokines and improved recovery of EEG activity and carotid artery perfusion. Histologically, IL-1Ra reduced microgliosis, IL-1β expression and caspase-3+ cells, and improved olig-2+ oligodendrocyte survival. Conclusion IL-1Ra improved EEG activity and markedly attenuated systemic inflammation, microgliosis and oligodendrocyte loss following LPS exposure in near-term fetal sheep. Further studies examining the long-term effects on brain maturation are now needed. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02238-4.
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Affiliation(s)
- Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Valerie A Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Alison Moxham
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Timothy J M Moss
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Marcel F Nold
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Paediatrics, Monash University, Melbourne, Victoria, Australia.,Monash Newborn, Monash Children's Hospital, Melbourne, Australia
| | - Claudia A Nold-Petry
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Justin M Dean
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, 27-31 Wright street, Melbourne, Victoria, 3168, Australia. .,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia.
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18
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Wassink G, Davidson JO, Crisostomo A, Zhou KQ, Galinsky R, Dhillon SK, Lear CA, Bennet L, Gunn AJ. Recombinant erythropoietin does not augment hypothermic white matter protection after global cerebral ischaemia in near-term fetal sheep. Brain Commun 2021; 3:fcab172. [PMID: 34409290 PMCID: PMC8364665 DOI: 10.1093/braincomms/fcab172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/31/2021] [Indexed: 01/07/2023] Open
Abstract
Therapeutic hypothermia for hypoxic-ischaemic encephalopathy provides partial white matter protection. Recombinant erythropoietin reduces demyelination after hypoxia-ischaemia, but it is unclear whether adjunct erythropoietin treatment can further improve outcomes after therapeutic hypothermia. Term-equivalent fetal sheep received sham-ischaemia (n = 9) or cerebral ischaemia for 30 min (ischaemia-vehicle, n = 8), followed by intravenous infusion of recombinant erythropoietin (ischaemia-Epo, n = 8; 5000 IU/kg bolus dose, then 833.3 IU/kg/h), cerebral hypothermia (ischaemia-hypothermia, n = 8), or recombinant erythropoietin plus hypothermia (ischaemia-Epo-hypothermia, n = 8), from 3 to 72 h post-ischaemia. Foetal brains were harvested at 7 days after cerebral ischaemia. Ischaemia was associated with marked loss of total Olig2-positive oligodendrocytes with reduced density of myelin and linearity of the white matter tracts (P < 0.01), and microglial induction and increased caspase-3-positive apoptosis. Cerebral hypothermia improved the total number of oligodendrocytes and restored myelin basic protein (P < 0.01), whereas recombinant erythropoietin partially improved myelin basic protein density and tract linearity. Both interventions suppressed microgliosis and caspase-3 (P < 0.05). Co-treatment improved 2′,3′-cyclic-nucleotide 3′-phosphodiesterase-myelin density compared to hypothermia, but had no other additive effect. These findings suggest that although hypothermia and recombinant erythropoietin independently protect white matter after severe hypoxia-ischaemia, they have partially overlapping anti-inflammatory and anti-apoptotic effects, with little additive benefit of combination therapy.
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Affiliation(s)
- Guido Wassink
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alyssa Crisostomo
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Kelly Q Zhou
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
| | | | - Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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19
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Prasad JD, Gunn KC, Davidson JO, Galinsky R, Graham SE, Berry MJ, Bennet L, Gunn AJ, Dean JM. Anti-Inflammatory Therapies for Treatment of Inflammation-Related Preterm Brain Injury. Int J Mol Sci 2021; 22:4008. [PMID: 33924540 PMCID: PMC8069827 DOI: 10.3390/ijms22084008] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/09/2021] [Accepted: 04/10/2021] [Indexed: 12/13/2022] Open
Abstract
Despite the prevalence of preterm brain injury, there are no established neuroprotective strategies to prevent or alleviate mild-to-moderate inflammation-related brain injury. Perinatal infection and inflammation have been shown to trigger acute neuroinflammation, including proinflammatory cytokine release and gliosis, which are associated with acute and chronic disturbances in brain cell survival and maturation. These findings suggest the hypothesis that the inhibition of peripheral immune responses following infection or nonspecific inflammation may be a therapeutic strategy to reduce the associated brain injury and neurobehavioral deficits. This review provides an overview of the neonatal immunity, neuroinflammation, and mechanisms of inflammation-related brain injury in preterm infants and explores the safety and efficacy of anti-inflammatory agents as potentially neurotherapeutics.
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Affiliation(s)
- Jaya D. Prasad
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
| | - Katherine C. Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
| | - Joanne O. Davidson
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia;
| | - Scott E. Graham
- Department of Molecular Medicine and Pathology, Faculty of Medical and Health Sciences, University of Auckland, Auckland 1010, New Zealand;
| | - Mary J. Berry
- Department of Pediatrics and Health Care, University of Otago, Dunedin 9016, New Zealand;
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
| | - Alistair J. Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
| | - Justin M. Dean
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, 85 Park Road, Grafton, Auckland 1010, New Zealand; (J.D.P.); (K.C.G.); (J.O.D.); (L.B.); (A.J.G.)
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20
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Galinsky R, van de Looij Y, Mitchell N, Dean JM, Dhillon SK, Yamaguchi K, Lear CA, Wassink G, Davidson JO, Nott F, Zahra VA, Kelly SB, King VJ, Sizonenko SV, Bennet L, Gunn AJ. Magnetic Resonance Imaging Correlates of White Matter Gliosis and Injury in Preterm Fetal Sheep Exposed to Progressive Systemic Inflammation. Int J Mol Sci 2020; 21:ijms21238891. [PMID: 33255257 PMCID: PMC7727662 DOI: 10.3390/ijms21238891] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/17/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Progressive fetal infection/inflammation is strongly associated with neural injury after preterm birth. We aimed to test the hypotheses that progressively developing fetal inflammation leads to neuroinflammation and impaired white matter development and that the histopathological changes can be detected using high-field diffusion tensor magnetic resonance imaging (MRI). Chronically instrumented preterm fetal sheep at 0.7 of gestation were randomly assigned to receive intravenous saline (control; n = 6) or a progressive infusion of lipopolysaccharide (LPS, 200 ng intravenous over 24 h then doubled every 24 h for 5 days to induce fetal inflammation, n = 7). Sheep were killed 10 days after starting the infusions, for histology and high-field diffusion tensor MRI. Progressive LPS infusion was associated with increased circulating interleukin (IL)-6 concentrations and moderate increases in carotid artery perfusion and the frequency of electroencephalogram (EEG) activity (p < 0.05 vs. control). In the periventricular white matter, fractional anisotropy (FA) was increased, and orientation dispersion index (ODI) was reduced (p < 0.05 vs. control for both). Histologically, in the same brain region, LPS infusion increased microglial activation and astrocyte numbers and reduced the total number of oligodendrocytes with no change in myelination or numbers of immature/mature oligodendrocytes. Numbers of astrocytes in the periventricular white matter were correlated with increased FA and reduced ODI signal intensities. Astrocyte coherence was associated with increased FA. Moderate astrogliosis, but not loss of total oligodendrocytes, after progressive fetal inflammation can be detected with high-field diffusion tensor MRI.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria 3800, Australia
| | - Yohan van de Looij
- Division of Child Development & Growth, Department of Pediatrics, Gynaecology & Obstetrics, School of Medicine, University of Geneva, 1015 Geneva, Switzerland; (Y.v.d.L.); (S.V.S.)
| | - Natasha Mitchell
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Justin M. Dean
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Simerdeep K. Dhillon
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Kyohei Yamaguchi
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Christopher A. Lear
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Guido Wassink
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Joanne O. Davidson
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Fraser Nott
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
| | - Valerie A. Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
| | - Sharmony B. Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria 3168, Australia; (F.N.); (V.A.Z.); (S.B.K.)
- Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria 3800, Australia
| | - Victoria J. King
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Stéphane V. Sizonenko
- Division of Child Development & Growth, Department of Pediatrics, Gynaecology & Obstetrics, School of Medicine, University of Geneva, 1015 Geneva, Switzerland; (Y.v.d.L.); (S.V.S.)
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
| | - Alistair J. Gunn
- Department of Physiology, University of Auckland, Auckland 1023, New Zealand; (R.G.); (N.M.); (J.M.D.); (S.K.D.); (K.Y.); (C.A.L.); (G.W.); (J.O.D.); (V.J.K.); (L.B.)
- Correspondence:
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21
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Badurdeen S, Gill AW, Kluckow M, Roberts CT, Galinsky R, Klink S, Miller SL, Davis PG, Schmölzer GM, Hooper SB, Polglase GR. Excess cerebral oxygen delivery follows return of spontaneous circulation in near-term asphyxiated lambs. Sci Rep 2020; 10:16443. [PMID: 33020561 PMCID: PMC7536421 DOI: 10.1038/s41598-020-73453-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 09/08/2020] [Indexed: 11/09/2022] Open
Abstract
Hypoxic-ischaemia renders the neonatal brain susceptible to early secondary injury from oxidative stress and impaired autoregulation. We aimed to describe cerebral oxygen kinetics and haemodynamics immediately following return of spontaneous circulation (ROSC) and evaluate non-invasive parameters to facilitate bedside monitoring. Near-term sheep fetuses [139 ± 2 (SD) days gestation, n = 16] were instrumented to measure carotid artery (CA) flow, pressure, right brachial arterial and jugular venous saturation (SaO2 and SvO2, respectively). Cerebral oxygenation (crSO2) was measured using near-infrared spectroscopy (NIRS). Following induction of severe asphyxia, lambs received cardiopulmonary resuscitation using 100% oxygen until ROSC, with oxygen subsequently weaned according to saturation nomograms as per current guidelines. We found that oxygen consumption did not rise following ROSC, but oxygen delivery was markedly elevated until 15 min after ROSC. CrSO2 and heart rate each correlated with oxygen delivery. SaO2 remained > 90% and was less useful for identifying trends in oxygen delivery. CrSO2 correlated inversely with cerebral fractional oxygen extraction. In conclusion, ROSC from perinatal asphyxia is characterised by excess oxygen delivery that is driven by rapid increases in cerebrovascular pressure, flow, and oxygen saturation, and may be monitored non-invasively. Further work to describe and limit injury mediated by oxygen toxicity following ROSC is warranted.
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Affiliation(s)
- Shiraz Badurdeen
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia.
- Newborn Research, Royal Women's Hospital, Melbourne, VIC, Australia.
| | - Andrew W Gill
- Centre for Neonatal Research and Education, University of Western Australia, Perth, WA, Australia
| | - Martin Kluckow
- Department of Neonatology, Royal North Shore Hospital, University of Sydney, Sydney, NSW, Australia
| | - Calum T Roberts
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
- Department of Paediatrics, Monash University, Clayton, VIC, Australia
- Monash Newborn, Monash Children's Hospital, Clayton, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
| | - Sarah Klink
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
| | - Suzanne L Miller
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
| | - Peter G Davis
- Newborn Research, Royal Women's Hospital, Melbourne, VIC, Australia
| | | | - Stuart B Hooper
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, The Hudson Institute of Medical Research, 27-31 Wright St, Clayton, VIC, 3168, Australia
- Department of Obstetrics and Gynaecology, Monash University, Victoria, Australia
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22
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Lear CA, Beacom MJ, Kasai M, Westgate JA, Galinsky R, Magawa S, Miyagi E, Ikeda T, Bennet L, Gunn AJ. Reply to the "Letter to the Editor: Mind the gap: epistemology of heart rate variability". Am J Physiol Regul Integr Comp Physiol 2020; 319:R345-R346. [PMID: 32845174 DOI: 10.1152/ajpregu.00208.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Christopher A Lear
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michael J Beacom
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michi Kasai
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Jenny A Westgate
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia
| | - Shoichi Magawa
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Etsuko Miyagi
- Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Tomoaki Ikeda
- Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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23
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Polglase GR, Schmölzer GM, Roberts CT, Blank DA, Badurdeen S, Crossley KJ, Miller SL, Stojanovska V, Galinsky R, Kluckow M, Gill AW, Hooper SB. Cardiopulmonary Resuscitation of Asystolic Newborn Lambs Prior to Umbilical Cord Clamping; the Timing of Cord Clamping Matters! Front Physiol 2020; 11:902. [PMID: 32848852 PMCID: PMC7406709 DOI: 10.3389/fphys.2020.00902] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/06/2020] [Indexed: 12/14/2022] Open
Abstract
Background: Current guidelines recommend immediate umbilical cord clamping (UCC) for newborns requiring chest compressions (CCs). Physiological-based cord clamping (PBCC), defined as delaying UCC until after lung aeration, has advantages over immediate UCC in mildly asphyxiated newborns, but its efficacy in asystolic newborns requiring CC is unknown. The aim of this study was to compare the cardiovascular response to CCs given prior to or after UCC in asystolic near-term lambs. Methods: Umbilical, carotid, pulmonary, and femoral arterial flows and pressures as well as systemic and cerebral oxygenation were measured in near-term sheep fetuses [139 ± 2 (SD) days gestation]. Fetal asphyxia was induced until asystole ensued, whereupon lambs received ventilation and CC before (PBCC; n = 16) or after (n = 12) UCC. Epinephrine was administered 1 min after ventilation onset and in 3-min intervals thereafter. The PBCC group was further separated into UCC at either 1 min (PBCC1, n = 8) or 10 min (PBCC10, n = 8) after return of spontaneous circulation (ROSC). Lambs were maintained for a further 30 min after ROSC. Results: The duration of CCs received and number of epinephrine doses required to obtain ROSC were similar between groups. After ROSC, we found no physiological benefits if UCC was delayed for 1 min compared to immediate cord clamping (ICC). However, if UCC was delayed for 10 min after ROSC, we found significant reductions in post-asphyxial rebound hypertension, cerebral blood flow, and cerebral oxygenation. The prevention of the post-asphyxial rebound hypertension in the PBCC10 group occurred due to the contribution of the placental circulation to a low peripheral resistance. As a result, left and right ventricular outputs continued to perfuse the placenta and were evidenced by reduced mean pulmonary blood flow, persistence of right-to-left shunting across the ductus arteriosus, and persistence of umbilical arterial and venous blood flows. Conclusion: It is possible to obtain ROSC after CC while the umbilical cord remains intact. There were no adverse effects of PBCC compared to ICC; however, the physiological changes observed after ROSC in the ICC and early PBCC groups may result in additional cerebral injury. Prolonging UCC after ROSC may provide significant physiological benefits that may reduce the risk of harm to the cerebral circulation.
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Affiliation(s)
- Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Georg M Schmölzer
- Centre for the Studies of Asphyxia and Resuscitation, Neonatal Research Unit, Royal Alexandra Hospital, Edmonton, AB, Canada
| | - Calum T Roberts
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - Douglas A Blank
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Paediatrics, Monash University, Melbourne, VIC, Australia
| | - Shiraz Badurdeen
- Newborn Research Centre, The Royal Women's Hospital, Melbourne, VIC, Australia
| | - Kelly J Crossley
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
| | - Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Martin Kluckow
- Department of Neonatology, Royal North Shore Hospital, The University of Sydney, Sydney, NSW, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Subiaco, WA, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
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Lear CA, Beacom MJ, Kasai M, Westgate JA, Galinsky R, Magawa S, Miyagi E, Ikeda T, Bennet L, Gunn AJ. Circulating catecholamines partially regulate T-wave morphology but not heart rate variability during repeated umbilical cord occlusions in fetal sheep. Am J Physiol Regul Integr Comp Physiol 2020; 319:R123-R131. [PMID: 32491938 DOI: 10.1152/ajpregu.00026.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fetal heart rate (FHR) variability (FHRV) and ST segment morphology are potential clinical indices of fetal well-being during labor. β-Adrenergic stimulation by circulating catecholamines has been hypothesized to contribute to both FHRV and ST segment morphology during labor, but this has not been tested during brief repeated fetal hypoxemia that is characteristic of labor. Near-term fetal sheep (0.85 gestation) received propranolol (β-adrenergic blockade; n = 10) or saline (n = 7) 30 min before being exposed to three 2-min complete umbilical cord occlusions (UCOs) separated by 3-min reperfusions. T/QRS ratio was calculated throughout UCOs and reperfusion periods, and measures of FHRV (RMSSD, SDNN, and STV) were calculated between UCOs. During the baseline period, before the start of UCOs, propranolol was associated with reduced FHR, SDNN, and STV but did not affect RMSSD or T/QRS ratio. UCOs were associated with rapid FHR decelerations and increased T/QRS ratio; propranolol significantly reduced FHR during UCOs and was associated with a slower rise in T/QRS ratio during the first UCOs, without affecting the maximal rise or T/QRS ratio during the second and third UCO. Between UCOs propranolol reduced FHR and T/QRS ratio but did not affect any measure of FHRV. These data demonstrate that circulating catecholamines do not contribute to FHRV during labor-like hypoxemia. Furthermore, circulating catecholamines did not contribute to the major rise in T/QRS ratio during labor-like hypoxemia but may regulate T/QRS ratio between brief hypoxemia.
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Affiliation(s)
- Christopher A Lear
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michael J Beacom
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Michi Kasai
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Jenny A Westgate
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research and Department of Obstetrics and Gynaecology, Monash University, Melbourne, Australia
| | - Shoichi Magawa
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Etsuko Miyagi
- Department of Obstetrics and Gynecology, Yokohama City University, Yokohama, Japan
| | - Tomoaki Ikeda
- Department of Obstetrics and Gynecology, Mie University, Mie, Japan
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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25
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Disdier C, Awa F, Chen X, Dhillon SK, Galinsky R, Davidson JO, Lear CA, Bennet L, Gunn AJ, Stonestreet BS. Lipopolysaccharide-induced changes in the neurovascular unit in the preterm fetal sheep brain. J Neuroinflammation 2020; 17:167. [PMID: 32466771 PMCID: PMC7257152 DOI: 10.1186/s12974-020-01852-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/21/2020] [Indexed: 02/06/2023] Open
Abstract
Background Exposure to inflammation during pregnancy can predispose to brain injury in premature infants. In the present study, we investigated the effects of prolonged exposure to inflammation on the cerebrovasculature of preterm fetal sheep. Methods Chronically instrumented fetal sheep at 103–104 days of gestation (full term is ~ 147 days) received continuous low-dose lipopolysaccharide (LPS) infusions (100 ng/kg over 24 h, followed by 250 ng/kg/24 h for 96 h plus boluses of 1 μg LPS at 48, 72, and 96 h) or the same volume of normal saline (0.9%, w/v). Ten days after the start of LPS exposure at 113–114 days of gestation, the sheep were killed, and the fetal brain perfused with formalin in situ. Vessel density, pericyte and astrocyte coverage of the blood vessels, and astrogliosis in the cerebral cortex and white matter were determined using immunohistochemistry. Results LPS exposure reduced (P < 0.05) microvascular vessel density and pericyte vascular coverage in the cerebral cortex and white matter of preterm fetal sheep, and increased the activation of perivascular astrocytes, but decreased astrocytic vessel coverage in the white matter. Conclusions Prolonged exposure to LPS in preterm fetal sheep resulted in decreased vessel density and neurovascular remodeling, suggesting that chronic inflammation adversely affects the neurovascular unit and, therefore, could contribute to long-term impairment of brain development.
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Affiliation(s)
- Clémence Disdier
- Department of Pediatrics, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University, 101 Dudley Street, Providence, RI, 02905, USA
| | - Fares Awa
- Department of Pediatrics, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University, 101 Dudley Street, Providence, RI, 02905, USA
| | - Xiaodi Chen
- Department of Pediatrics, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University, 101 Dudley Street, Providence, RI, 02905, USA
| | | | - Robert Galinsky
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Barbara S Stonestreet
- Department of Pediatrics, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University, 101 Dudley Street, Providence, RI, 02905, USA.
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26
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Galinsky R, Dean JM, Lingam I, Robertson NJ, Mallard C, Bennet L, Gunn AJ. A Systematic Review of Magnesium Sulfate for Perinatal Neuroprotection: What Have We Learnt From the Past Decade? Front Neurol 2020; 11:449. [PMID: 32536903 PMCID: PMC7267212 DOI: 10.3389/fneur.2020.00449] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/28/2020] [Indexed: 12/14/2022] Open
Abstract
There is an important unmet need to improve long term outcomes of encephalopathy for preterm and term infants. Meta-analyses of large controlled trials suggest that maternal treatment with magnesium sulfate (MgSO4) is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth. However, to date, follow up to school age has found an apparent lack of long-term clinical benefit. Because of this inconsistency, it remains controversial whether MgSO4 offers sustained neuroprotection. We systematically reviewed preclinical and clinical studies reported from January 1 2010, to January 31 2020 to evaluate the most recent advances and knowledge gaps relating to the efficacy of MgSO4 for the treatment of perinatal brain injury. The outcomes of MgSO4 in preterm and term-equivalent animal models of perinatal encephalopathy were highly inconsistent between studies. None of the perinatal rodent studies that suggested benefit directly controlled body or brain temperature. The majority of the studies did not control for sex, study long term histological and functional outcomes or use pragmatic treatment regimens and many did not report controlling for potential study bias. Finally, most of the recent preterm or term human studies that tested the potential of MgSO4 for perinatal neuroprotection were relatively underpowered, but nevertheless, suggest that any improvements in neurodevelopment were at best modest or absent. On balance, these data suggest that further rigorous testing in translational preclinical models of perinatal encephalopathy is essential to ensure safety and best regimens for optimal preterm neuroprotection, and before further clinical trials of MgSO4 for perinatal encephalopathy at term are undertaken.
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Affiliation(s)
- Robert Galinsky
- Department of Obstetrics and Gynecology, The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Melbourne, VIC, Australia.,Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Ingran Lingam
- Neonatology, Institute for Women's Health, University College London, London, United Kingdom
| | - Nicola J Robertson
- Neonatology, Institute for Women's Health, University College London, London, United Kingdom
| | - Carina Mallard
- Department of Neuroscience and Physiology, University of Gothenburg, Sahlgrenska Academy, Gothenburg, Sweden
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, University of Auckland, Auckland, New Zealand
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27
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Galinsky R, Dhillon SK, Dean JM, Davidson JO, Lear CA, Wassink G, Nott F, Kelly SB, Fraser M, Yuill C, Bennet L, Gunn AJ. Tumor necrosis factor inhibition attenuates white matter gliosis after systemic inflammation in preterm fetal sheep. J Neuroinflammation 2020; 17:92. [PMID: 32293473 PMCID: PMC7087378 DOI: 10.1186/s12974-020-01769-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 03/09/2020] [Indexed: 12/21/2022] Open
Abstract
Background Increased circulating levels of tumor necrosis factor (TNF) are associated with greater risk of impaired neurodevelopment after preterm birth. In this study, we tested the hypothesis that systemic TNF inhibition, using the soluble TNF receptor Etanercept, would attenuate neuroinflammation in preterm fetal sheep exposed to lipopolysaccharide (LPS). Methods Chronically instrumented preterm fetal sheep at 0.7 of gestation were randomly assigned to receive saline (control; n = 7), LPS infusion (100 ng/kg i.v. over 24 h then 250 ng/kg/24 h for 96 h plus 1 μg LPS boluses at 48, 72, and 96 h, to induce inflammation; n = 8) or LPS plus two i.v. infusions of Etanercept (2 doses, 5 mg/kg infused over 30 min, 48 h apart) started immediately before LPS-exposure (n = 8). Sheep were killed 10 days after starting infusions, for histology. Results LPS boluses were associated with increased circulating TNF, interleukin (IL)-6 and IL-10, electroencephalogram (EEG) suppression, hypotension, tachycardia, and increased carotid artery perfusion (P < 0.05 vs. control). In the periventricular and intragyral white matter, LPS exposure increased gliosis, TNF-positive cells, total oligodendrocytes, and cell proliferation (P < 0.05 vs control), but did not affect myelin expression or numbers of neurons in the cortex and subcortical regions. Etanercept delayed the rise in circulating IL-6, prolonged the increase in IL-10 (P < 0.05 vs. LPS), and attenuated EEG suppression, hypotension, and tachycardia after LPS boluses. Histologically, Etanercept normalized LPS-induced gliosis, and increase in TNF-positive cells, proliferation, and total oligodendrocytes. Conclusion TNF inhibition markedly attenuated white matter gliosis but did not affect mature oligodendrocytes after prolonged systemic inflammation in preterm fetal sheep. Further studies of long-term brain maturation are now needed.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Simerdeep K Dhillon
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Justin M Dean
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Joanne O Davidson
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Christopher A Lear
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Guido Wassink
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Fraser Nott
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Sharmony B Kelly
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Mhoyra Fraser
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Caroline Yuill
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand
| | - Alistair Jan Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Private bag 92019, Auckland, 1023, New Zealand.
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28
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Stojanovska V, Barton SK, Tolcos M, Gill AW, Kluckow M, Miller SL, Zahra V, Hooper SB, Galinsky R, Polglase GR. The Effect of Antenatal Betamethasone on White Matter Inflammation and Injury in Fetal Sheep and Ventilated Preterm Lambs. Dev Neurosci 2019; 40:497-507. [PMID: 30840951 DOI: 10.1159/000496466] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/20/2018] [Indexed: 11/19/2022] Open
Abstract
Antenatal administration of betamethasone (BM) is a common antecedent of preterm birth, but there is limited information about its impact on the acute evolution of preterm neonatal brain injury. We aimed to compare the effects of maternal BM in combination with mechanical ventilation on the white matter (WM) of late preterm sheep. At 0.85 of gestation, pregnant ewes were randomly assigned to receive intra-muscular (i.m.) saline (n = 9) or i.m. BM (n = 13). Lambs were delivered and unventilated controls (UVCSal, n = 4; UVCBM, n = 6) were humanely killed without intervention; ventilated lambs (VentSal, n = 5; VentBM, n = 7) were injuriously ventilated for 15 min, followed by conventional ventilation for 75 min. Cardiovascular and cerebral haemodynamics and oxygenation were measured continuously. The cerebral WM underwent assessment of inflammation and injury, and oxidative stress was measured in the cerebrospinal fluid (CSF). In the periventricular and subcortical WM tracts, the proportion of amoeboid (activated) microglia, the density of astrocytes, and the number of blood vessels with protein extravasation were higher in UVCBM than in UVCSal (p < 0.05 for all). During ventilation, tidal volume, mean arterial pressure, carotid blood flow, and oxygen delivery were higher in -VentBM lambs (p < 0.05 vs. VentSal). In the subcortical WM, microglial infiltration was increased in the VentSal group compared to UVCSal. The proportion of activated microglia and protein extravasation was higher in the VentBM group compared to VentSal within the periventricular and subcortical WM tracts (p < 0.05). CSF oxidative stress was increased in the VentBM group compared to UVCSal, UVCBM, and VentSal groups (p < 0.05). Antenatal BM was associated with inflammation and vascular permeability in the WM of late preterm fetal sheep. During the immediate neonatal period, the increased carotid perfusion and oxygen delivery in BM-treated lambs was associated with increased oxidative stress, microglial activation and microvascular injury.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Samantha K Barton
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Andrew W Gill
- Centre for Neonatal Research and Education, The University of Western Australia, Crawley, Washington, Australia
| | - Martin Kluckow
- Department of Neonatal Medicine, Royal North Shore Hospital and University of Sydney, Sydney, New South Wales, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Valerie Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia, .,Department of Obstetrics and Gynaecology, Monash University, Melbourne, Victoria, Australia,
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29
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Dhillon SK, Lear CA, Galinsky R, Wassink G, Davidson JO, Juul S, Robertson NJ, Gunn AJ, Bennet L. The fetus at the tipping point: modifying the outcome of fetal asphyxia. J Physiol 2018; 596:5571-5592. [PMID: 29774532 DOI: 10.1113/jp274949] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 04/13/2018] [Indexed: 12/13/2022] Open
Abstract
Brain injury around birth is associated with nearly half of all cases of cerebral palsy. Although brain injury is multifactorial, particularly after preterm birth, acute hypoxia-ischaemia is a major contributor to injury. It is now well established that the severity of injury after hypoxia-ischaemia is determined by a dynamic balance between injurious and protective processes. In addition, mothers who are at risk of premature delivery have high rates of diabetes and antepartum infection/inflammation and are almost universally given treatments such as antenatal glucocorticoids and magnesium sulphate to reduce the risk of death and complications after preterm birth. We review evidence that these common factors affect responses to fetal asphyxia, often in unexpected ways. For example, glucocorticoid exposure dramatically increases delayed cell loss after acute hypoxia-ischaemia, largely through secondary hyperglycaemia. This critical new information is important to understand the effects of clinical treatments of women whose fetuses are at risk of perinatal asphyxia.
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Affiliation(s)
| | - Christopher A Lear
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Department of Physiology, University of Auckland, Auckland, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Melbourne, Victoria, Australia
| | - Guido Wassink
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Sandra Juul
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Alistair J Gunn
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
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30
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Lear CA, Wassink G, Westgate JA, Nijhuis JG, Ugwumadu A, Galinsky R, Bennet L, Gunn AJ. The peripheral chemoreflex: indefatigable guardian of fetal physiological adaptation to labour. J Physiol 2018; 596:5611-5623. [PMID: 29604081 DOI: 10.1113/jp274937] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/29/2018] [Indexed: 01/10/2023] Open
Abstract
The fetus is consistently exposed to repeated periods of impaired oxygen (hypoxaemia) and nutrient supply in labour. This is balanced by the healthy fetus's remarkable anaerobic tolerance and impressive ability to mount protective adaptations to hypoxaemia. The most important mediator of fetal adaptations to brief repeated hypoxaemia is the peripheral chemoreflex, a rapid reflex response to acute falls in arterial oxygen tension. The overwhelming majority of fetuses are able to respond to repeated uterine contractions without developing hypotension or hypoxic-ischaemic injury. In contrast, fetuses who are either exposed to severe hypoxaemia, for example during uterine hyperstimulation, or enter labour with reduced anaerobic reserve (e.g. as shown by severe fetal growth restriction) are at increased risk of developing intermittent hypotension and cerebral hypoperfusion. It is remarkable to note that when fetuses develop hypotension during such repeated severe hypoxaemia, it is not mediated by impaired reflex adaptation, but by failure to maintain combined ventricular output, likely due to a combination of exhaustion of myocardial glycogen and evolving myocardial injury. The chemoreflex is suppressed by relatively long periods of severe hypoxaemia of 1.5-2 min, longer than the typical contraction. Even in this setting, the peripheral chemoreflex is consistently reactivated between contractions. These findings demonstrate that the peripheral chemoreflex is an indefatigable guardian of fetal adaptation to labour.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Jan G Nijhuis
- Department of Obstetrics and Gynaecology, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Austin Ugwumadu
- Department of Obstetrics and Gynaecology, St George's, University of London, London, UK
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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31
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Bennet L, Galinsky R, Draghi V, Lear CA, Davidson JO, Unsworth CP, Gunn AJ. Time and sex dependent effects of magnesium sulphate on post-asphyxial seizures in preterm fetal sheep. J Physiol 2018; 596:6079-6092. [PMID: 29572829 DOI: 10.1113/jp275627] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/12/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS We evaluated the effect of magnesium sulphate (MgSO4 ) on seizures induced by asphyxia in preterm fetal sheep. MgSO4 did not prevent seizures, but significantly reduced the total duration, number of seizures, seizure amplitude and average seizure burden. Saline-asphyxia male fetuses had significantly more seizures than female fetuses, but male fetuses showed significantly greater reduction in seizures during MgSO4 infusion than female fetuses. A circadian profile of seizure activity was observed in all fetuses, with peak seizures seen around 04.00-06.00 h on the first and second days after the end of asphyxia. This study is the first to demonstrate that MgSO4 has utility as an anti-seizure agent after hypoxia-ischaemia. More information is needed about the mechanisms mediating the effect of MgSO4 on seizures and sexual dimorphism, and the influence of circadian rhythms on seizure expression. ABSTRACT Seizures are common in newborns after asphyxia at birth and are often refractory to anti-seizure agents. Magnesium sulphate (MgSO4 ) has anticonvulsant effects and is increasingly given to women in preterm labour for potential neuroprotection. There is limited information on its effects on perinatal seizures. We examined the hypothesis that MgSO4 infusion would reduce fetal seizures after asphyxia in utero. Preterm fetal sheep at 0.7 gestation (104 days, term = 147 days) were given intravenous infusions of either saline (n = 14) or MgSO4 (n = 12, 160 mg bolus + 48 mg h-1 infusion over 48 h). Fetuses underwent umbilical cord occlusion (UCO) for 25 min, 24 h after the start of infusion. The start time for seizures did not differ between groups, but MgSO4 significantly reduced the total number of seizures (P < 0.001), peak seizure amplitude (P < 0.05) and seizure burden (P < 0.005). Within the saline-asphyxia group, male fetuses had significantly more seizures than females (P < 0.05). Within the MgSO4 -asphyxia group, although both sexes had fewer seizures than the saline-asphyxia group, the greatest effect of MgSO4 was on male fetuses, with reduced numbers of seizures (P < 0.001) and seizure burden (P < 0.005). Only 1 out of 6 MgSO4 males had seizures on the second day post-UCO compared to 5 out of 6 MgSO4 female fetuses (P = 0.08). Finally, seizures showed a circadian profile with peak seizures between 04.00 and 06.00 h on the first and second day post-UCO. Collectively, these results suggest that MgSO4 may have utility in treating perinatal seizures and has sexually dimorphic effects.
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Affiliation(s)
- Laura Bennet
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Vittoria Draghi
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Charles P Unsworth
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, The Department of Physiology, The University of Auckland, Auckland, New Zealand
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Lear CA, Davidson JO, Mackay GR, Drury PP, Galinsky R, Quaedackers JS, Gunn AJ, Bennet L. Antenatal dexamethasone before asphyxia promotes cystic neural injury in preterm fetal sheep by inducing hyperglycemia. J Cereb Blood Flow Metab 2018; 38:706-718. [PMID: 28387144 PMCID: PMC5888852 DOI: 10.1177/0271678x17703124] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Antenatal glucocorticoid therapy significantly improves the short-term systemic outcomes of prematurely born infants, but there is limited information available on their impact on neurodevelopmental outcomes in at-risk preterm babies exposed to perinatal asphyxia. Preterm fetal sheep (0.7 of gestation) were exposed to a maternal injection of 12 mg dexamethasone or saline followed 4 h later by asphyxia induced by 25 min of complete umbilical cord occlusion. In a subsequent study, fetuses received titrated glucose infusions followed 4 h later by asphyxia to examine the hypothesis that hyperglycemia mediated the effects of dexamethasone. Post-mortems were performed 7 days after asphyxia for cerebral histology. Maternal dexamethasone before asphyxia was associated with severe, cystic brain injury compared to diffuse injury after saline injection, with increased numbers of seizures, worse recovery of brain activity, and increased arterial glucose levels before, during, and after asphyxia. Glucose infusions before asphyxia replicated these adverse outcomes, with a strong correlation between greater increases in glucose before asphyxia and greater neural injury. These findings strongly suggest that dexamethasone exposure and hyperglycemia can transform diffuse injury into cystic brain injury after asphyxia in preterm fetal sheep.
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Affiliation(s)
- Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Georgia R Mackay
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Paul P Drury
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | | | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
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Galinsky R, Dhillon SK, Lear CA, Yamaguchi K, Wassink G, Gunn AJ, Bennet L. Magnesium sulfate and sex differences in cardiovascular and neural adaptations during normoxia and asphyxia in preterm fetal sheep. Am J Physiol Regul Integr Comp Physiol 2018; 315:R205-R217. [PMID: 29561649 DOI: 10.1152/ajpregu.00390.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Magnesium sulfate (MgSO4) is recommended for preterm neuroprotection, preeclampsia, and preterm labor prophylaxis. There is an important, unmet need to carefully test clinical interventions in both sexes. Therefore, we aimed to investigate cardiovascular and neurophysiological adaptations to MgSO4 during normoxia and asphyxia in preterm male and female fetal sheep. Fetuses were instrumented at 98 ± 1 days of gestation (term = 147 days). At 104 days, unanesthetized fetuses were randomly assigned to intravenous MgSO4 ( n = 12 female, 10 male) or saline ( n = 13 female, 10 male). At 105 days fetuses underwent umbilical cord occlusion for up to 25 min. Occlusions were stopped early if mean arterial blood pressure (MAP) fell below 8 mmHg or asystole occurred for >20 s. During normoxia, MgSO4 was associated with similar reductions in fetal heart rate (FHR), EEG power, and movement in both sexes ( P < 0.05 vs. saline controls) and suppression of α- and β-spectral band power in males ( P < 0.05 vs. saline controls). During occlusion, similar FHR and MAP responses occurred in MgSO4-treated males and females compared with saline controls. Recovery of FHR and MAP after release of occlusion was more prolonged in MgSO4-treated males ( P < 0.05 vs. saline controls). During and after occlusion, EEG power was lower in MgSO4-treated females ( P < 0.05 vs. saline controls). In conclusion, MgSO4 infusion was associated with subtle sex-specific effects on EEG spectral power and cardiac responses to asphyxia in utero, possibly reflecting sex-specific differences in interneuronal connectivity and regulation of cardiac output.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland , Auckland , New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research , Clayton, VIC , Australia
| | | | - Christopher A Lear
- Department of Physiology, University of Auckland , Auckland , New Zealand
| | - Kyohei Yamaguchi
- Department of Physiology, University of Auckland , Auckland , New Zealand
| | - Guido Wassink
- Department of Physiology, University of Auckland , Auckland , New Zealand
| | - Alistair J Gunn
- Department of Physiology, University of Auckland , Auckland , New Zealand
| | - Laura Bennet
- Department of Physiology, University of Auckland , Auckland , New Zealand
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Galinsky R, Lear CA, Dean JM, Wassink G, Dhillon SK, Fraser M, Davidson JO, Bennet L, Gunn AJ. Complex interactions between hypoxia-ischemia and inflammation in preterm brain injury. Dev Med Child Neurol 2018; 60:126-133. [PMID: 29194585 DOI: 10.1111/dmcn.13629] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/17/2017] [Indexed: 12/12/2022]
Abstract
UNLABELLED Children surviving preterm birth have a high risk of disability, particularly cognitive and learning problems. There is extensive clinical and experimental evidence that disability is now primarily related to dysmaturation of white and gray matter, defined by failure of oligodendrocyte maturation and neuronal dendritic arborization, rather than cell death alone. The etiology of this dysmaturation is multifactorial, with contributions from hypoxia-ischemia, infection/inflammation and barotrauma. Intriguingly, these factors can interact to both increase and decrease damage. In this review we summarize preclinical and clinical evidence that all of these factors trigger secondary or chronic inflammation and gliosis. Thus, we hypothesize that these shared pathological features play a key role in a final common pathway that leads to the impaired neural maturation and connectivity and cognitive/motor impairments that are commonly observed in infants born preterm. This raises the possibility that secondary or chronic inflammation may be a viable therapeutic target for delayed interventions to improve neurodevelopmental outcomes after preterm birth. WHAT THIS PAPER ADDS Hypoxia-ischemia, infection/inflammation, and barotrauma/volutrauma all contribute to preterm brain injury. Multiple different triggers of preterm brain injury are associated with central nervous system dysmaturation. Secondary brain inflammation may be a viable target to improve neurodevelopment after preterm birth.
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Affiliation(s)
- Robert Galinsky
- The Department of Physiology, University of Auckland, Auckland, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Christopher A Lear
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Mhoyra Fraser
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Department of Physiology, University of Auckland, Auckland, New Zealand
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Stojanovska V, Atik A, Nitsos I, Skiöld B, Barton SK, Zahra VA, Rodgers K, Hooper SB, Polglase GR, Galinsky R. Effects of Intrauterine Inflammation on Cortical Gray Matter of Near-Term Lambs. Front Pediatr 2018; 6:145. [PMID: 29963540 PMCID: PMC6013568 DOI: 10.3389/fped.2018.00145] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/01/2018] [Indexed: 12/25/2022] Open
Abstract
Introduction: Ventilation causes cerebral white matter inflammation and injury, which is exacerbated by intrauterine inflammation. However, the effects on cortical gray matter are not well-known. Our aim was to examine the effect of ventilation on the cerebral cortex of near-term lambs exposed to intrauterine inflammation. Method:Pregnant ewes at 119 ± 1 days gestation received an intra-amniotic injection of saline or lipopolysaccharide (LPS; 10 mg). Seven days later, lambs were randomized to either a high tidal volume injurious ventilation strategy (INJSALN = 6, INJLPSN = 5) or a protective ventilation strategy (PROTSALN = 5, PROTLPSN = 6). Respiratory parameters, heart rate and blood gases were monitored during the neonatal period. At post-mortem, the brain was collected and processed for immunohistochemical assessment. Neuronal density (NeuN), apoptotic cell death (caspase 8 and TUNEL), microglial density (Iba-1), astrocytic density (GFAP), and vascular protein extravasation (sheep serum) were assessed within the frontal, parietal, temporal and occipital lobes of the cerebral cortex. Results:A significant reduction in the number of neurons in all cortical layers except 4 was observed in LPS-exposed lambs compared to controls (layer #1: p = 0.041; layers #2 + 3: p = 0.023; layers #5 + 6: p = 0.016). LPS treatment caused a significant increase in gray matter area, indicative of edema. LPS+ventilation did not cause apoptotic cell death in the gray matter. Astrogliosis was not observed following PROT or INJ ventilation, with or without LPS exposure. LPS exposure was associated with vascular protein extravasation. Conclusion:Ventilation had little effect on gray matter inflammation and injury. Intrauterine inflammation reduced neuronal cell density, caused edema of the cortical gray matter, and blood vessel extravasation in the brain of near-term lambs.
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Affiliation(s)
- Vanesa Stojanovska
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Anzari Atik
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Béatrice Skiöld
- Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden
| | - Samantha K Barton
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Centre of Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Valerie A Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Karyn Rodgers
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, VIC, Australia
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Abstract
Perinatal encephalopathy remains a major cause of disability, such as cerebral palsy. Therapeutic hypothermia is now well established to partially reduce risk of disability in late preterm/term infants. However, new and complementary therapeutic targets are needed to further improve outcomes. There is increasing evidence that glia play a key role in neural damage after hypoxia-ischemia and infection/inflammation. In this review, we discuss the role of astrocytic gap junction (connexin) hemichannels in the spread of neural injury after hypoxia-ischemia and/or infection/inflammation. Potential mechanisms of hemichannel mediated injury likely involve impaired intracellular calcium handling, loss of blood-brain barrier integrity and release of adenosine triphosphate (ATP) resulting in over-activation of purinergic receptors. We propose the hypothesis that inflammation-induced opening of connexin hemichannels is a key regulating event that initiates a vicious cycle of excessive ATP release, which in turn propagates activation of purinergic receptors on microglia and astrocytes. This suggests that developing new neuroprotective strategies for preterm infants will benefit from a detailed understanding of glial and connexin hemichannel responses.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland, Auckland, New Zealand; The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
| | - Joanne O Davidson
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Justin M Dean
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, University of Auckland, Auckland, New Zealand
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Lear CA, Galinsky R, Wassink G, Yamaguchi K, Davidson JO, Westgate JA, Bennet L, Gunn AJ. Reply from Christopher A. Lear, Robert Galinsky, Guido Wassink, Kyohei Yamaguchi, Joanne O. Davidson, Jenny A. Westgate, Laura Bennet and Alistair J. Gunn. J Physiol 2017; 595:6081-6083. [PMID: 28856754 PMCID: PMC5577537 DOI: 10.1113/jp274800] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Christopher A. Lear
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Kyohei Yamaguchi
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
- Department of Obstetrics and GynaecologyMie University Graduate School of MedicineMieJapan
| | - Joanne O. Davidson
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Jenny A. Westgate
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
- Department of Obstetrics and GynaecologyUniversity of AucklandAucklandNew Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
| | - Alistair J. Gunn
- The Fetal Physiology and Neuroscience Group, Department of PhysiologyUniversity of AucklandAucklandNew Zealand
- Starship Children's HospitalAucklandNew Zealand
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Galinsky R, Davidson JO, Lear CA, Bennet L, Green CR, Gunn AJ. Connexin hemichannel blockade improves survival of striatal GABA-ergic neurons after global cerebral ischaemia in term-equivalent fetal sheep. Sci Rep 2017; 7:6304. [PMID: 28740229 PMCID: PMC5524909 DOI: 10.1038/s41598-017-06683-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 06/15/2017] [Indexed: 11/17/2022] Open
Abstract
Basal ganglia injury at term remains a major cause of disability, such as cerebral palsy. In this study we tested the hypotheses that blockade of astrocytic connexin hemichannels with a mimetic peptide would improve survival of striatal phenotypic neurons after global cerebral ischaemia in term-equivalent fetal sheep, and that neuronal survival would be associated with electrophysiological recovery. Fetal sheep (0.85 gestation) were randomly assigned to receive a short or long (1 or 25 h) intracerebroventricular infusion of a mimetic peptide or vehicle, starting 90 minutes after 30 minutes of cerebral ischaemia. Sheep were killed 7 days after ischaemia. Cerebral ischaemia was associated with reduced numbers of calbindin-28k, calretinin, parvalbumin and GAD positive striatal neurons (P < 0.05 ischaemia + vehicle, n = 6 vs. sham ischaemia, n = 6) but not ChAT or nNOS positive neurons. Short infusion of peptide (n = 6) did not significantly improve survival of any striatal phenotype. Long infusion of peptide (n = 6) was associated with increased survival of calbindin-28k, calretinin, parvalbumin and GAD positive neurons (P < 0.05 vs. ischaemia + vehicle). Neurophysiological recovery was associated with improved survival of calbindin-28k, calretinin and parvalbumin positive striatal neurons (P < 0.05 for all). In conclusion, connexin hemichannel blockade after cerebral ischaemia in term-equivalent fetal sheep improves survival of striatal GABA-ergic neurons.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, The University of Auckland, Auckland, New Zealand.,The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
| | - Joanne O Davidson
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Colin R Green
- Department of Ophthalmology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, The University of Auckland, Auckland, New Zealand.
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Galinsky R, Draghi V, Wassink G, Davidson JO, Drury PP, Lear CA, Gunn AJ, Bennet L. Magnesium sulfate reduces EEG activity but is not neuroprotective after asphyxia in preterm fetal sheep. J Cereb Blood Flow Metab 2017; 37:1362-1373. [PMID: 27317658 PMCID: PMC5453457 DOI: 10.1177/0271678x16655548] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Magnesium sulfate is now widely recommended for neuroprotection for preterm birth; however, this has been controversial because there is little evidence that magnesium sulfate is neuroprotective. Preterm fetal sheep (104 days gestation; term is 147 days) were randomly assigned to receive sham occlusion (n = 7), i.v. magnesium sulfate (n = 10) or saline (n = 8) starting 24 h before asphyxia until 24 h after asphyxia. Sheep were killed 72 h after asphyxia. Magnesium sulfate infusion reduced electroencephalograph power and fetal movements before asphyxia. Magnesium sulfate infusion did not affect electroencephalograph power during recovery, but was associated with marked reduction of the post-asphyxial seizure burden (mean ± SD: 34 ± 18 min vs. 107 ± 74 min, P < 0.05). Magnesium sulfate infusion did not affect subcortical neuronal loss. In the intragyral and periventricular white matter, magnesium sulfate was associated with reduced numbers of all (Olig-2+ve) oligodendrocytes in the intragyral (125 ± 23 vs. 163 ± 38 cells/field) and periventricular white matter (162 ± 39 vs. 209 ± 44 cells/field) compared to saline-treated controls ( P < 0.05), but no effect on microglial induction or astrogliosis. In conclusion, a clinically comparable dose of magnesium sulfate showed significant anticonvulsant effects after asphyxia in preterm fetal sheep, but did not reduce asphyxia-induced brain injury and exacerbated loss of oligodendrocytes.
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Affiliation(s)
- Robert Galinsky
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand.,2 The Ritchie Centre, the Hudson Institute of Medical Research, Clayton, Victoria, Australia
| | - Vittoria Draghi
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Paul P Drury
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- 1 Department of Physiology, University of Auckland, Auckland, New Zealand
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Wassink G, Davidson JO, Dhillon SK, Fraser M, Galinsky R, Bennet L, Gunn AJ. Partial white and grey matter protection with prolonged infusion of recombinant human erythropoietin after asphyxia in preterm fetal sheep. J Cereb Blood Flow Metab 2017; 37:1080-1094. [PMID: 27207167 PMCID: PMC5363482 DOI: 10.1177/0271678x16650455] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Perinatal asphyxia in preterm infants remains a significant contributor to abnormal long-term neurodevelopmental outcomes. Recombinant human erythropoietin has potent non-haematopoietic neuroprotective properties, but there is limited evidence for protection in the preterm brain. Preterm (0.7 gestation) fetal sheep received sham asphyxia (sham occlusion) or asphyxia induced by umbilical cord occlusion for 25 min, followed by an intravenous infusion of vehicle (occlusion-vehicle) or recombinant human erythropoietin (occlusion-Epo, 5000 international units by slow push, then 832.5 IU/h), starting 30 min after asphyxia and continued until 72 h. Recombinant human erythropoietin reduced neuronal loss and numbers of caspase-3-positive cells in the striatal caudate nucleus, CA3 and dentate gyrus of the hippocampus, and thalamic medial nucleus ( P < 0.05 vs. occlusion-vehicle). In the white matter tracts, recombinant human erythropoietin increased total, but not immature/mature oligodendrocytes ( P < 0.05 vs. occlusion-vehicle), with increased cell proliferation and reduced induction of activated caspase-3, microglia and astrocytes ( P < 0.05). Finally, occlusion-Epo reduced seizure burden, with more rapid recovery of electroencephalogram power, spectral edge frequency, and carotid blood flow. In summary, prolonged infusion of recombinant human erythropoietin after severe asphyxia in preterm fetal sheep was partially neuroprotective and improved electrophysiological and cerebrovascular recovery, in association with reduced apoptosis and inflammation.
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Affiliation(s)
- Guido Wassink
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Simerdeep K Dhillon
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Mhoyra Fraser
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand.,2 The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Laura Bennet
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- 1 Department of Physiology, The University of Auckland, Auckland, New Zealand
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Galinsky R. Cerebral economics: shedding light on supply and demand in the developing brain. J Physiol 2017; 595:1011-1012. [PMID: 28122394 DOI: 10.1113/jp273690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Robert Galinsky
- Department of Physiology, University of Auckland, Auckland, New Zealand and The Ritchie Centre, Hudson Institute of Medical Research, Victoria, Australia
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Alahmari DM, Skiöld B, Barton SK, Nitsos I, McDonald C, Miller SL, Zahra V, Galinsky R, Wu Q, Farrell MJ, Moss TJ, Hooper SB, Pearson JT, Polglase GR. Diffusion Tensor Imaging Colour Mapping Threshold for Identification of Ventilation-Induced Brain Injury after Intrauterine Inflammation in Preterm Lambs. Front Pediatr 2017; 5:70. [PMID: 28424764 PMCID: PMC5380678 DOI: 10.3389/fped.2017.00070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/20/2017] [Indexed: 11/23/2022] Open
Abstract
PURPOSE The aim of this study is to examine whether advanced magnetic resonance imaging (MRI) techniques can detect early brain injury caused by intrauterine inflammation and inappropriate initial respiratory support in preterm lambs. HYPOTHESIS Neuropathology caused by intrauterine inflammation is exacerbated by mechanical ventilation at birth and is detectable with advanced MRI techniques. METHODS Pregnant ewes received intra-amniotic lipopolysaccharide (LPS) 7 days prior to delivery at ~125 days of gestation (85% of gestation), whereupon lambs were delivered and randomised to receive an injurious (LPS + INJ, n = 6) or protective (LPS + PROT, n = 6) ventilation strategy. MRI of the brain was conducted 90 min after preterm delivery, using structural, diffusion tensor imaging (DTI), and magnetic resonance spectroscopy (MRS) techniques. A colour map threshold technique was utilised to compare distributions of low diffusivity voxels in the brains of LPS-exposed lambs with those not exposed to LPS (PROT, n = 7 PROT and INJ, n = 10). RESULTS No overt cerebral injury was identified on structural MRI images of any lamb. However, on DTI, axial diffusivity, radial diffusivity, and mean diffusivity values were lower and significantly more heterogeneous in specific brain regions of lambs in the LPS + INJ group compared to the LPS + PROT group. Colour mapping revealed lower diffusivity in the thalamus, periventricular white matter, internal capsule, and frontal white matter in the LPS + INJ group compared to LPS + PROT group. The MRS peak area ratios of lactate, relative to those for the metabolites creatine, choline, and N-acetylaspartate, were not different between LPS-exposed groups. Lambs exposed to LPS had lower diffusivity within the white matter regions assessed than non-LPS-treated control lambs. CONCLUSION DTI colour map threshold techniques detected early brain injury in preterm lambs exposed to intrauterine inflammation and detected differences between injurious and protective ventilation strategies. DTI mapping approaches are potentially useful for early detection of subtle brain injury in premature infants.
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Affiliation(s)
- Dhafer M Alahmari
- Department of Medical Imaging and Radiation Sciences, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia
| | - Beatrice Skiöld
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Samantha K Barton
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Ilias Nitsos
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Courtney McDonald
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Suzanne L Miller
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology and Paediatrics, Monash University, Clayton, VIC, Australia
| | - Valerie Zahra
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Robert Galinsky
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Physiology, University of Auckland, Grafton, New Zealand
| | - Qizhu Wu
- Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia
| | - Michael John Farrell
- Department of Medical Imaging and Radiation Sciences, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia
| | - Timothy J Moss
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology and Paediatrics, Monash University, Clayton, VIC, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology and Paediatrics, Monash University, Clayton, VIC, Australia
| | - James T Pearson
- Monash Biomedical Imaging, Monash University, Clayton, VIC, Australia.,Department of Physiology, Monash University, Clayton, VIC, Australia.,Department of Cardiac Physiology, National Cerebral and Cardiovascular Center, Suita, Osaka, Japan
| | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, VIC, Australia.,Department of Obstetrics and Gynaecology and Paediatrics, Monash University, Clayton, VIC, Australia
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Galinsky R, Dean JM, Lear CA, Davidson JO, Dhillon S, Wassink G, Bennet L, Gunn AJ. In the Era of Therapeutic Hypothermia, How Well Do Studies of Perinatal Neuroprotection Control Temperature? Dev Neurosci 2016; 39:7-22. [PMID: 27988510 DOI: 10.1159/000452859] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 10/26/2016] [Indexed: 11/19/2022] Open
Abstract
In the era of therapeutic hypothermia, reliable preclinical studies are integral to successfully identify neuroprotective strategies to further improve outcomes of encephalopathy at term. We reviewed preclinical neuroprotection studies reported between January 2014 and June 2016 to assess the use of effective temperature monitoring and control. As a secondary measure, we examined whether studies addressed other methodological issues such as stage of brain development, sex differences, the timing of the treatment relative to the insult, and the histological and functional endpoints used after hypoxia-ischemia. The extent and duration of temperature monitoring was highly inconsistent. Only a minority of papers monitored core (19/61; 31%) or brain temperature (3/61; 5%). Most (40/45) of the neuroprotectants either were likely to affect thermoregulation or their impact is unknown. In 85% of papers neonatal rodents were used (67% at P7); 51% of papers did not report the sex of the animals or tested the effect of potential neuroprotectants on just one sex. In 76% of studies, treatment was before or immediately after the insult (within the first 2 h), and few studies assessed long-term histological and behavioral outcomes. In conclusion, many recent preclinical neonatal studies cannot exclude the possibility that apparent neuroprotection might be related to drug-induced hypothermia or to other methodological choices. Close monitoring and control of brain temperature during, as well as for many days after, experimental hypoxia-ischemia are now critical to reliably develop new ways to improve neurodevelopmental outcomes after perinatal hypoxic-ischemic encephalopathy.
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Affiliation(s)
- Robert Galinsky
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Galinsky R, Lear CA, Yamaguchi K, Wassink G, Westgate JA, Bennet L, Gunn AJ. Cholinergic and β-adrenergic control of cardiovascular reflex responses to brief repeated asphyxia in term-equivalent fetal sheep. Am J Physiol Regul Integr Comp Physiol 2016; 311:R949-R956. [PMID: 27654399 DOI: 10.1152/ajpregu.00340.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 09/12/2016] [Indexed: 11/22/2022]
Abstract
The role of cholinergic and β-adrenergic activity in mediating fetal cardiovascular recovery from brief repeated episodes of asphyxia consistent with established labor, remains unclear. In this study, we tested the effect of cholinergic and β-adrenergic blockade on the fetal chemoreflex and fetal heart rate (FHR) overshoot responses during brief repeated asphyxia at rates consistent with early or active labor. Chronically instrumented fetal sheep at 0.85 of gestation received either i.v. atropine sulfate (cholinergic blockade, n=8) or vehicle (n=7) followed by 3 x 1-minute umbilical cord occlusions repeated every 5 minutes (1:5; consistent with early labor), or i.v. propranolol hydrochloride (β-adrenergic blockade, n=6) or vehicle (n=6) followed by 3 x 2-minute occlusions repeated every 5 minutes (2:5; consistent with active labor). In vehicle-controls, 1:5 occlusions were associated with rapid and sustained FHR decelerations followed by rapid return of FHR to baseline values after release of the occlusion. Cholinergic blockade abolished FHR decelerations during occlusions and caused FHR overshoot after release of the occlusion (P<0.05 vs. control 1:5). In vehicle-controls, 2:5 occlusions caused rapid and sustained FHR decelerations followed by FHR overshoot after release of the occlusion. β-adrenergic blockade was associated with greater reduction in FHR during occlusions and attenuated FHR overshoot (P<0.05 vs. control 2:5). These data demonstrate that the FHR overshoot pattern after asphyxia is mediated by a combination of attenuated parasympathetic activity and increased β-adrenergic stimulation of the fetal heart.
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45
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Lear CA, Galinsky R, Wassink G, Yamaguchi K, Davidson JO, Westgate JA, Bennet L, Gunn AJ. The myths and physiology surrounding intrapartum decelerations: the critical role of the peripheral chemoreflex. J Physiol 2016; 594:4711-25. [PMID: 27328617 DOI: 10.1113/jp271205] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 02/17/2016] [Indexed: 11/08/2022] Open
Abstract
A distinctive pattern of recurrent rapid falls in fetal heart rate, called decelerations, are commonly associated with uterine contractions during labour. These brief decelerations are mediated by vagal activation. The reflex triggering this vagal response has been variably attributed to a mechanoreceptor response to fetal head compression, to baroreflex activation following increased blood pressure during umbilical cord compression, and/or a Bezold-Jarisch reflex response to reduced venous return from the placenta. Although these complex explanations are still widespread today, there is no consistent evidence that they are common during labour. Instead, the only mechanism that has been systematically investigated, proven to be reliably active during labour and, crucially, capable of producing rapid decelerations is the peripheral chemoreflex. The peripheral chemoreflex is triggered by transient periods of asphyxia that are a normal phenomenon associated with all uterine contractions. This should not cause concern as the healthy fetus has a remarkable ability to adapt to these repeated but short periods of asphyxia. This means that the healthy fetus is typically not at risk of hypotension and injury during uncomplicated labour even during repeated brief decelerations. The physiologically incorrect theories surrounding decelerations that ignore the natural occurrence of repeated asphyxia probably gained widespread support to help explain why many babies are born healthy despite repeated decelerations during labour. We propose that a unified and physiological understanding of intrapartum decelerations that accepts the true nature of labour is critical to improve interpretation of intrapartum fetal heart rate patterns.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Kyohei Yamaguchi
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, Mie University Graduate School of Medicine, Mie, Japan
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jenny A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Department of Obstetrics and Gynaecology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand.,Starship Children's Hospital, Auckland, New Zealand
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46
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Galinsky R, Davidson JO, Drury PP, Wassink G, Lear CA, van den Heuij LG, Gunn AJ, Bennet L. Magnesium sulphate and cardiovascular and cerebrovascular adaptations to asphyxia in preterm fetal sheep. J Physiol 2015; 594:1281-93. [PMID: 26077461 DOI: 10.1113/jp270614] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/08/2015] [Indexed: 11/08/2022] Open
Abstract
Magnesium sulphate is a standard therapy for eclampsia in pregnancy and is widely recommended for perinatal neuroprotection during threatened preterm labour. MgSO4 is a vasodilator and negative inotrope. Therefore the aim of this study was to investigate the effect of MgSO4 on the cardiovascular and cerebrovascular responses of the preterm fetus to asphyxia. Fetal sheep were instrumented at 98 ± 1 days of gestation (term = 147 days). At 104 days, unanaesthetised fetuses were randomly assigned to receive an intravenous infusion of MgSO4 (n = 6) or saline (n = 9). At 105 days all fetuses underwent umbilical cord occlusion for 25 min. Before occlusion, MgSO4 treatment reduced heart rate and increased femoral blood flow (FBF) and vascular conductance compared to controls. During occlusion, carotid and femoral arterial conductance and blood flows were higher in MgSO4-treated fetuses than controls. After occlusion, fetal heart rate was lower and carotid and femoral arterial conductance and blood flows were higher in MgSO4-treated fetuses than controls. Femoral arterial waveform height and width were increased during MgSO4 infusion, consistent with increased stroke volume. MgSO4 did not alter the fetal neurophysiological or nuchal electromyographic responses to asphyxia. These data demonstrate that a clinically comparable dose of MgSO4 increased FBF and stroke volume without impairing mean arterial pressure (MAP) or carotid blood flow (CaBF) during and immediately after profound asphyxia. Thus, MgSO4 may increase perfusion of peripheral vascular beds during adverse perinatal events.
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Affiliation(s)
- Robert Galinsky
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Paul P Drury
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Christopher A Lear
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | | | - Alistair J Gunn
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
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Lear CA, Galinsky R, Wassink G, Mitchell CJ, Davidson JO, Westgate JA, Bennet L, Gunn AJ. Sympathetic neural activation does not mediate heart rate variability during repeated brief umbilical cord occlusions in near-term fetal sheep. J Physiol 2015; 594:1265-77. [PMID: 25864517 DOI: 10.1113/jp270125] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 04/07/2015] [Indexed: 11/08/2022] Open
Abstract
Changes in fetal heart rate variability (FHRV) and ST segment elevation (measured as the T/QRS ratio) are used to evaluate fetal adaptation to labour. The sympathetic nervous system (SNS) is an important contributor to FHRV under healthy normoxic conditions, and is critical for rapid support of blood pressure during brief labour-like asphyxia. However, although it has been assumed that SNS activity contributes to FHRV during labour; this has never been tested, and it is unclear whether the SNS contributes to the rapid increase in T/QRS ratio during brief asphyxia. Thirteen chronically instrumented fetal sheep at 0.85 of gestation received either chemical sympathectomy with 6-hydroxydopamine (6-OHDA; n = 6) or sham treatment (control; n = 7), followed 4-5 days later by 2 min episodes of complete umbilical cord occlusion repeated every 5 min for up to 4 h, or until mean arterial blood pressure fell to <20 mmHg for two successive occlusions. FHRV was decreased before occlusions in the 6-OHDA group (P < 0.05) and 2-4.5 h during recovery after occlusions (P < 0.05) compared to the control group. During each occlusion there was a rapid increase in T/QRS ratio. Between successive occlusions the T/QRS ratio rapidly returned to baseline, and FHRV increased above baseline in both groups (P < 0.05), with no significant effect of sympathectomy on FHRV or T/QRS ratio. In conclusion, these data show that SNS activity does not mediate the increase in FHRV between repeated episodes of brief umbilical cord occlusion or the transient increase in T/QRS ratio during occlusions.
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Affiliation(s)
- Christopher A Lear
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Guido Wassink
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Clinton J Mitchell
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Jennifer A Westgate
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- The Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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48
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Galinsky R, Bennet L, Groenendaal F, Lear CA, Tan S, van Bel F, Juul SE, Robertson NJ, Mallard C, Gunn AJ. Magnesium is not consistently neuroprotective for perinatal hypoxia-ischemia in term-equivalent models in preclinical studies: a systematic review. Dev Neurosci 2015; 36:73-82. [PMID: 24854050 DOI: 10.1159/000362206] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Accepted: 03/13/2014] [Indexed: 11/19/2022] Open
Abstract
There is an important unmet need to further improve the outcome of neonatal encephalopathy in term infants. Meta-analyses of large controlled trials now suggest that maternal magnesium sulfate (MgSO4) therapy is associated with a reduced risk of cerebral palsy and gross motor dysfunction after premature birth, but that it has no effect on death or disability. Because of this inconsistency, it remains controversial whether MgSO4 is clinically neuroprotective and, thus, it is unclear whether it would be appropriate to test MgSO4 for treatment of encephalopathy in term infants. We therefore systematically reviewed the preclinical evidence for neuroprotection with MgSO4 before or after hypoxic-ischemic encephalopathy (HIE) in term-equivalent perinatal and adult animals. The outcomes were highly inconsistent between studies. Although there were differences in dose and timing of administration, there was evidence that beneficial effects of MgSO4 were associated with confounding mild hypothermia and, strikingly, the studies that included rigorous maintenance of environmental temperature or body temperature consistently suggested a lack of effect. On balance, these preclinical studies suggest that peripherally administered MgSO4 is unlikely to be neuroprotective. Rigorous testing in translational animal models of perinatal HIE is needed before MgSO4 should be considered in clinical trials for encephalopathy in term infants.
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Wassink G, Barrett RD, Davidson JO, Bennet L, Galinsky R, Dragunow M, Gunn AJ. Hypothermic neuroprotection is associated with recovery of spectral edge frequency after asphyxia in preterm fetal sheep. Stroke 2015; 46:585-7. [PMID: 25586829 DOI: 10.1161/strokeaha.114.008484] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Electroencephalographic recovery is predictive of outcome after perinatal hypoxia-ischemia, but it is unknown whether early changes in electroencephalographic can predict the response to therapeutic hypothermia in the preterm brain. METHODS 0.7 gestation fetal sheep received umbilical cord occlusion or sham occlusion for 25 minutes, followed by sham hypothermia or whole-body cooling started either 30 minutes or 5 hours after occlusion and continued for 72 hours. RESULTS Early but not delayed hypothermia reduced neuronal loss and microglial induction in the striatum, with faster recovery of spectral edge frequency, reduced seizure burden, and less suppression of electroencephalographic amplitude (P<0.05). CONCLUSIONS Recovery of higher electroencephalographic frequencies may be a biomarker of effective hypothermic neuroprotection in the preterm-equivalent brain.
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Affiliation(s)
- Guido Wassink
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Robert D Barrett
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Michael Dragunow
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- From the Department of Physiology (G.W., R.D.B., J.O.D., L.B., R.G., A.J.G.), and Department of Anatomy with Radiology (M.D.), University of Auckland, Auckland, New Zealand.
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Lear CA, Koome ME, Davidson JO, Drury PP, Quaedackers JS, Galinsky R, Gunn AJ, Bennet L. The effects of dexamethasone on post-asphyxial cerebral oxygenation in the preterm fetal sheep. J Physiol 2014; 592:5493-505. [PMID: 25384775 DOI: 10.1113/jphysiol.2014.281253] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Exposure to clinical doses of the glucocorticoid dexamethasone increases brain activity and causes seizures in normoxic preterm fetal sheep without causing brain injury. In contrast, the same treatment after asphyxia increased brain injury. We hypothesised that increased injury was in part mediated by a mismatch between oxygen demand and oxygen supply. In preterm fetal sheep at 0.7 gestation we measured cerebral oxygenation using near-infrared spectroscopy, electroencephalographic (EEG) activity, and carotid blood flow (CaBF) from 24 h before until 72 h after asphyxia induced by 25 min of umbilical cord occlusion. Ewes received dexamethasone intramuscularly (12 mg 3 ml(-1)) or saline 15 min after the end of asphyxia. Fetuses were studied for 3 days after occlusion. During the first 6 h of recovery after asphyxia, dexamethasone treatment was associated with a significantly greater fall in CaBF (P < 0.05), increased carotid vascular resistance (P < 0.001) and a greater fall in cerebral oxygenation as measured by the difference between oxygenated and deoxygenated haemoglobin (delta haemoglobin; P < 0.05). EEG activity was similarly suppressed in both groups. From 6 to 10 h onward, dexamethasone treatment was associated with a return of CaBF to saline control levels, increased EEG power (P < 0.005), greater epileptiform transient activity (P < 0.001), increased oxidised cytochrome oxidase (P < 0.05) and an attenuated increase in [delta haemoglobin] (P < 0.05). In conclusion, dexamethasone treatment after asphyxia is associated with greater hypoperfusion in the critical latent phase, leading to impaired intracerebral oxygenation that may exacerbate neural injury after asphyxia.
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Affiliation(s)
- Christopher A Lear
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Miriam E Koome
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Joanne O Davidson
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Paul P Drury
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Josine S Quaedackers
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Robert Galinsky
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Fetal Physiology and Neuroscience Group, Department of Physiology, The University of Auckland, Auckland, New Zealand
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