Effect of Depth and Duration of Cooling on Death or Disability at Age 18 Months Among Neonates With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

Prevalence of hearing impairment in neonatal encephalopathy due to hypoxia-ischemia: a systematic review and meta-analysis

BACKGROUND

This systematic review was undertaken to estimate the overall prevalence of hearing impairment in survivors of neonatal HIE.

METHODS

PubMed, EMBASE, CINAHL, EMCARE and Cochrane databases, mednar (gray literature) were searched till January 2023. Randomized controlled trials and observational studies were included. The main outcome was estimation of overall prevalence of hearing impairment in survivors of HIE.

RESULTS

A total of 71studies (5821 infants assessed for hearing impairment) were included of which 56 were from high income countries (HIC) and 15 from low- or middle-income countries (LMIC). Overall prevalence rate of hearing impairment in cooled infants was 5% (95% CI: 3-6%, n = 4868) and 3% (95% CI: 1-6%, n = 953) in non-cooled HIE infants. The prevalence rate in cooled HIE infants in LMICs was 7% (95% CI: 2-15%) and in HICs was 4% (95% CI: 3-5%). The prevalence rate in non-cooled HIE infants in LMICs was 8% (95% CI: 2-17%) and HICs was 2% (95% CI: 0-4%).

CONCLUSIONS

These results would be useful for counseling parents, and in acting as benchmark when comparing institutional data, and while monitoring future RCTs testing new interventions in HIE. There is a need for more data from LMICs and standardization of reporting hearing impairment.

IMPACT

The overall prevalence rate of hearing impairment in cooled infants with HIE was 5% (95% CI: 3-6%) and 3% (95% CI: 1-6%) in the non-cooled infants. The prevalence rate in cooled HIE infants in LMICs was 7% (95% CI: 2-15%) and in HICs was 4% (95% CI: 3-5%). The prevalence rate in non-cooled HIE infants in LMICs was 8% (95% CI: 2-17%) and HICs was 2% (95% CI: 0-4%). These results would be useful for counseling parents, and in acting as benchmark when comparing institutional data, and while monitoring future RCTs testing new interventions in HIE.

Esophageal Versus Rectal Temperature Monitoring During Whole-Body Therapeutic Hypothermia for Hypoxic-Ischemic Encephalopathy: Association with Short- and Long-Term Outcomes

OBJECTIVE

To compare the short- and long-term outcomes of infants with hypoxic-ischemic encephalopathy (HIE) treated with whole-body therapeutic hypothermia (TH), monitored by esophageal vs rectal temperature.

STUDY DESIGN

We conducted a secondary analysis of the multicenter High-Dose Erythropoietin for Asphyxia and Encephalopathy (HEAL) trial. All infants had moderate or severe HIE and were treated with whole-body TH. The primary outcome was death or neurodevelopmental impairment (NDI) at 22-36 months of age. Secondary outcomes included seizures, evidence of brain injury on magnetic resonance imaging, and complications of hypothermia. Logistic regression was used with adjustment for disease severity and site as clustering variable because cooling modality differed by site.

RESULTS

Of the 500 infants who underwent TH, 294 (59%) and 206 (41%) had esophageal and rectal temperature monitoring, respectively. There were no differences in death or NDI, seizures, or evidence of injury on magnetic resonance imaging between the 2 groups. Infants treated with TH and rectal temperature monitoring had lower odds of overcooling (OR 0.52, 95% CI 0.34-0.80) and lower odds of hypotension (OR 0.57, 95% CI 0.39-0.84) compared with those with esophageal temperature monitoring.

CONCLUSIONS

Although infants undergoing TH with esophageal monitoring were more likely to experience overcooling and hypotension, the rate of death or NDI was similar whether esophageal monitoring or rectal temperature monitoring was used. Further studies are needed to investigate whether esophageal temperature monitoring during TH is associated with an increased risk of overcooling and hypotension.

Determining the Effect of Birth Weight on Therapeutic Hypothermia in Neonates with Hypoxic-Ischemic Encephalopathy

OBJECTIVE

 We examine the effect of birth weight (BW) for gestational age (GA) on the temperatures reached during the treatment of neonatal hypoxic-ischemic encephalopathy (HIE) with therapeutic hypothermia (TH).

STUDY DESIGN

 Retrospective data of 1,736 neonates with HIE who received TH were extracted from the Canadian Neonatal Network database for neonates admitted from 2010 to 2017. Neonates were stratified into three BW groups: small for GA < 10th centile, large for GA > 90th centile, and according to GA 10th to 89th centile at a given gestation using Canadian population data norms.

RESULTS

 There was no significant difference in the lowest temperature reached, the likelihood of overshooting temperatures < 32.5°C during TH, or the change of encephalopathy stages among the three groups.

CONCLUSION

 BW for GA did not appear to influence the temperatures neonates reached during hypothermia or encephalopathy stage following TH.

KEY POINT

· Therapeutic hypothermia is well tolerated irrespective of weight for age. · SGA infants achieved and maintained target temperature similar to AGA and LGA babies. · Change in the Sarnat stage after hypothermia was similar across all birth weight groups.

Neuroprotective efficacy of hypothermia and Inter-alpha Inhibitor Proteins after hypoxic ischemic brain injury in neonatal rats

Therapeutic hypothermia is the standard of care for hypoxic-ischemic (HI) encephalopathy. Inter-alpha Inhibitor Proteins (IAIPs) attenuate brain injury after HI in neonatal rats. Human (h) IAIPs (60 ​mg/kg) or placebo (PL) were given 15 ​min, 24 and 48 ​h to postnatal (P) day-7 rats after carotid ligation and 8% oxygen for 90 ​min with (30 ​°C) and without (36 ​°C) exposure to hypothermia 1.5 ​h after HI for 3 ​h. Hemispheric volume atrophy (P14) and neurobehavioral tests including righting reflex (P8-P10), small open field (P13-P14), and negative geotaxis (P14) were determined. Hemispheric volume atrophy in males was reduced (P ​< ​0.05) by 41.9% in the normothermic-IAIP and 28.1% in the hypothermic-IAIP compared with the normothermic-PL group, and in females reduced (P ​< ​0.05) by 30.3% in the normothermic-IAIP, 45.7% in hypothermic-PL, and 55.2% in hypothermic-IAIP compared with the normothermic-PL group after HI. Hypothermia improved (P ​< ​0.05) the neuroprotective effects of hIAIPs in females. The neuroprotective efficacy of hIAIPs was comparable to hypothermia in female rats (P ​= ​0.183). Treatment with hIAIPs, hypothermia, and hIAIPs with hypothermia decreased (P ​< ​0.05) the latency to enter the peripheral zone in the small open field test in males. We conclude that hIAIPs provide neuroprotection from HI brain injury that is comparable to the protection by hypothermia, hypothermia increases the effects of hIAIPs in females, and hIAIPs and hypothermia exhibit some sex-related differential effects.

A phase I trial of caffeine to evaluate safety in infants with hypoxic-ischemic encephalopathy

OBJECTIVE

Caffeine provides neuroprotection following hypoxic-ischemic injury in animals. We characterized the safety of escalating doses of caffeine in infants with hypoxic-ischemic encephalopathy (HIE) receiving therapeutic hypothermia.

STUDY DESIGN

Phase I trial of infants undergoing therapeutic hypothermia for HIE receiving IV caffeine 20 mg/kg followed by up to two daily doses of 5 mg/kg (n = 9) or 10 mg/kg (n = 8). Safety was evaluated based on adverse events and frequency of pre-specified outcomes compared to data from the Whole-Body Hypothermia for HIE trial (Shankaran, 2005).

RESULTS

Twelve of 17 (71%) infants had ≥1 adverse event during the study period. The frequency of clinical outcomes related to HIE were not statistically different from outcomes in infants receiving hypothermia in the Whole-Body Hypothermia for HIE trial.

CONCLUSION

Caffeine administration was well tolerated. A larger study is required to determine the optimal dose and evaluate drug safety and efficacy.

CLINICAL TRIAL

ClinicalTrials.gov Identifier: NCT03913221.

COHESION: a core outcome set for the treatment of neonatal encephalopathy

BACKGROUND

Heterogeneity in outcomes reported in trials of interventions for the treatment of neonatal encephalopathy (NE) makes evaluating the effectiveness of treatments difficult. Developing a core outcome set for NE treatment would enable researchers to measure and report the same outcomes in future trials. This would minimise waste, ensure relevant outcomes are measured and enable evidence synthesis. Therefore, we aimed to develop a core outcome set for treating NE.

METHODS

Outcomes identified from a systematic review of the literature and interviews with parents were prioritised by stakeholders (n = 99 parents/caregivers, n = 101 healthcare providers, and n = 22 researchers/ academics) in online Delphi surveys. Agreement on the outcomes was achieved at online consensus meetings attended by n = 10 parents, n = 18 healthcare providers, and n = 13 researchers/ academics.

RESULTS

Seven outcomes were included in the final core outcome set: survival; brain injury on imaging; neurological status at discharge; cerebral palsy; general cognitive ability; quality of life of the child, and adverse events related to treatment.

CONCLUSION

We developed a core outcome set for the treatment of NE. This will allow future trials to measure and report the same outcomes and ensure results can be compared. Future work should identify how best to measure the COS.

IMPACT

We have identified seven outcomes that should be measured and reported in all studies for the treatment of neonatal encephalopathy. Previously, a core outcome set for neonatal encephalopathy treatments did not exist. This will help to reduce heterogeneity in outcomes reported in clinical trials and other studies, and help researchers identify the best treatments for neonatal encephalopathy.

Feasibility and Safety of Sildenafil to Repair Brain Injury Secondary to Birth Asphyxia (SANE-01): A Randomized, Double-blind, Placebo-controlled Phase Ib Clinical Trial

OBJECTIVE

To test feasibility and safety of administering sildenafil in neonates with neonatal encephalopathy (NE), developing brain injury despite therapeutic hypothermia (TH).

STUDY DESIGN

We performed a randomized, double-blind, placebo-controlled phase Ib clinical trial between 2016 and 2019 in neonates with moderate or severe NE, displaying brain injury on day-2 magnetic resonance imaging (MRI) despite TH. Neonates were randomized (2:1) to 7-day sildenafil or placebo (2 mg/kg/dose enterally every 12 hours, 14 doses). Outcomes included feasibility and safety (primary outcomes), pharmacokinetics (secondary), and day-30 neuroimaging and 18-month neurodevelopment assessments (exploratory).

RESULTS

Of the 24 enrolled neonates, 8 were randomized to sildenafil and 3 to placebo. A mild decrease in blood pressure was reported in 2 of the 8 neonates after initial dose, but not with subsequent doses. Sildenafil plasma steady-state concentration was rapidly reached, but decreased after TH discontinuation. Twelve percent of neonates (1/8) neonates died in the sildenafil group and 0% (0/3) in the placebo group. Among surviving neonates, partial recovery of injury, fewer cystic lesions, and less brain volume loss on day-30 magnetic resonance imaging were noted in 71% (5/7) of the sildenafil group and in 0% (0/3) of the placebo group. The rate of death or survival to 18 months with severe neurodevelopmental impairment was 57% (4/7) in the sildenafil group and 100% (3/3) in the placebo group.

CONCLUSIONS

Sildenafil was safe and well-absorbed in neonates with NE treated with TH. Optimal dosing needs to be established. Evaluation of a larger number of neonates through subsequent phases II and III trials is required to establish efficacy.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.govNCT02812433.

Whole-Blood Gene Expression Profile After Hypoxic-Ischemic Encephalopathy

Importance

Induced hypothermia, the standard treatment for hypoxic-ischemic encephalopathy (HIE) in high-income countries (HICs), is less effective in the low-income populations in South Asia, who have the highest disease burden.

Objective

To investigate the differences in blood genome expression profiles of neonates with HIE from an HIC vs neonates with HIE from South Asia.

Design, Setting, and Participants

This case-control study analyzed data from (1) a prospective observational study involving neonates with moderate or severe HIE who underwent whole-body hypothermia between January 2017 and June 2019 and age-matched term healthy controls in Italy and (2) a randomized clinical trial involving neonates with moderate or severe HIE in India, Sri Lanka, and Bangladesh recruited between August 2015 and February 2019. Data were analyzed between October 2020 and August 2023.

Exposure

Whole-blood RNA that underwent next-generation sequencing.

Main Outcome and Measures

The primary outcomes were whole-blood genome expression profile at birth associated with adverse outcome (death or disability at 18 months) after HIE in the HIC and South Asia cohorts and changes in whole-genome expression profile during the first 72 hours after birth in neonates with HIE and healthy controls from the HIC cohort. Blood samples for RNA extraction were collected before whole-body hypothermia at 4 time points (6, 24, 48, and 72 hours after birth) for the HIC cohort. Only 1 blood sample was drawn within 6 hours after birth for the South Asia cohort.

Results

The HIC cohort was composed of 35 neonates (21 females [60.0%]) with a median (IQR) birth weight of 3.3 (3.0-3.6) kg and gestational age of 40.0 (39.0-40.6) weeks. The South Asia cohort consisted of 99 neonates (57 males [57.6%]) with a median (IQR) birth weight of 2.9 (2.7-3.3) kg and gestational age of 39.0 (38.0-40.0) weeks. Healthy controls included 14 neonates (9 females [64.3%]) with a median (IQR) birth weight of 3.4 (3.2-3.7) kg and gestational age of 39.2 (38.9-40.4) weeks. A total of 1793 significant genes in the HIC cohort and 99 significant genes in the South Asia cohort were associated with adverse outcome (false discovery rate <0.05). Only 11 of these genes were in common, and all had opposite direction in fold change. The most significant pathways associated with adverse outcome were downregulation of eukaryotic translation initiation factor 2 signaling in the HIC cohort (z score = -4.56; P < .001) and aldosterone signaling in epithelial cells in the South Asia cohort (z score = null; P < .001). The genome expression profile of neonates with HIE (n = 35) at birth, 24 hours, 48 hours, and 72 hours remained significantly different from that of age-matched healthy controls in the HIC cohort (n = 14).

Conclusions and Relevance

This case-control study found that disease mechanisms underlying HIE were primarily associated with acute hypoxia in the HIC cohort and nonacute hypoxia in the South Asia cohort. This finding might explain the lack of hypothermic neuroprotection.

Synergistic effect of sildenafil combined with controlled hypothermia to alleviate microglial activation after neonatal hypoxia-ischemia in rats

BACKGROUND AND PURPOSE

The only validated treatment to prevent brain damage associated with hypoxia-ischemia (HI) encephalopathy of the newborn is controlled hypothermia with limited benefits. Additional putative neuroprotective drug candidates include sildenafil citrate, a phosphodiesterase-type 5 inhibitor. The main objective of this preclinical study is to assess its ability to reduce HI-induced neuroinflammation, in particular through its potential effect on microglial activation.

METHODS

HI was induced in P10 Sprague-Dawley rats by unilateral carotid permanent artery occlusion and hypoxia (HI) and treated by either hypothermia (HT) alone, Sildenafil (Sild) alone or combined treatment (SildHT). Lesion size and glial activation were analyzed by immunohistochemistry, qRT-PCR, and proteomic analyses performed at P13.

RESULTS

None of the treatments was associated with a significant early reduction in lesion size 72h after HI, despite significant changes in tissue loss distribution. Significant reductions in both Iba1 + (within the ipsilateral hemisphere) and GFAP + cells (within the ipsilateral hippocampus) were observed in SildHT group, but not in the other treatment groups. In microglia-sorted cells, pro-inflammatory markers, i.e. Il1b, Il6, Nos2, and CD86 were significantly downregulated in SildHT treatment group only. These changes were restricted to the ipsilateral hemisphere, were not evidenced in sorted astrocytes, and were not sex dependent. Proteomic analyses in sorted microglia refined the pro-inflammatory effect of HI and confirmed a biologically relevant impact of SildHT on specific molecular pathways including genes related to neutrophilic functions.

CONCLUSIONS

Our findings suggest that Sildenafil combined with controlled hypothermia produces maximum effect in mitigating microglial activation induced by HI through complex proteomic regulation. The reduction of neuroinflammation induced by Sildenafil may represent an interesting therapeutic strategy for neonatal neuroprotection.

Neonatal Hypoxic-Ischemic Encephalopathy and Hypothermia Treatment

Neonatal hypoxic-ischemic encephalopathy (HIE) is an important clinical entity because it is associated with death and long-term disability, including cognitive impairment, cerebral palsy, seizures, and neurosensory deficits. Over the past 40 years, there has been an intensive search to identify therapies to improve the prognosis of neonates with HIE. Hypothermia treatment represents the culmination of laboratory investigations including small and large animal studies, followed by pilot human studies, and, finally, randomized controlled trials to establish efficacy and safety. Clinical trials have demonstrated that hypothermia treatment reduces mortality and improves early childhood outcome among survivors. Hypoxic-ischemic encephalopathy is a multi-system disease process that requires intensive medical support for brain monitoring and monitoring of non-central nervous system organ dysfunction. Treatment must be conducted in a level III or IV neonatal intensive care unit with infrastructure for an integrated approach to care for critically ill neonates. Hypothermia treatment is the first and currently the only therapy to improve outcomes for neonates with HIE and indicates that HIE is modifiable. However, outcomes likely can be improved further. Hypothermia treatment has accelerated investigation of other therapies to combine with hypothermia. It has also stimulated a more intensive approach to brain monitoring, which allows earlier intervention for complications. Finally, HIE and hypothermia treatment negatively influences the psychological state of affected families, and there is growing recognition of the importance of trauma-informed principles to guide medical professionals.

Growth and developmental outcomes of infants with hypoxic ischemic encephalopathy

Despite advances in obstetric care, hypoxic ischemic encephalopathy (HIE) remains a significant disease burden. We determined the national trends of HIE prevalence, therapeutic hypothermia (TH) use, mortality, and outcomes from 2012 to 2019. This study included term infants diagnosed with HIE between 2012 and 2019 from the National Health Insurance Service database. The prevalence of HIE was 2.4 per 1000 births without significant change during the period. TH was performed in approximately 6.7% of infants with HIE, and the annual variation ranged from 2.4 to 12.5%. The mortality among all term infants with HIE was 4.6%. The mortality rate among infants with HIE and TH significantly declined from 40 to 16.9% during the eight years. Infants with TH had higher mortality, increased use of inhaled nitric oxide, and more invasive ventilator use, indicating greater disease severity in the TH group. Infants with TH also showed significantly poorer outcomes, including delayed development, cerebral palsy, sensorineural hearing loss, and seizure, compared to infants without TH (p < 0.0001). With the increasing application of TH, mortality and developmental outcomes among infants with HIE have been improving in the past eight years in Korea. Further efforts to improve outcomes should be needed.

Intranasal insulin attenuates hypoxia-ischemia-induced short-term sensorimotor behavioral disturbances, neuronal apoptosis, and brain damage in neonatal rats

There is a significant need for additional therapy to improve outcomes for newborns with acute Hypoxic-ischemic (HI) encephalopathy (HIE). New evidence suggests that insulin could be neuroprotective. This study aimed to investigate whether intranasal insulin attenuates HI-induced brain damage and neurobehavioral dysfunction in neonatal rats. Postnatal day 10 (P10), Sprague-Dawley rat pups were randomly divided into Sham + Vehicle, Sham + Insulin, HI + Vehicle, and HI + Insulin groups with equal male-to-female ratios. Pups either had HI by permanent ligation of the right common carotid artery followed by 90 min of hypoxia (8% O2) or sham surgery followed by room air exposure. Immediately after HI or Sham, pups were given fluorescence-tagged insulin (Alex-546-insulin)/vehicle, human insulin (25 μg), or vehicle in each nare under anesthesia. Shortly after administration, widespread Alex-546-insulin-binding cells were detected in the brain, primarily co-localized with neuronal nuclei-positive neurons on double-immunostaining. In the hippocampus, phospho-Akt was activated in a subset of Alex-546-insulin double-labeled cells, suggesting activation of the Akt/PI3K pathway in these neurons. Intranasal insulin (InInsulin) reduced HI-induced sensorimotor behavioral disturbances at P11. InInsulin prevented HI-induced increased Fluoro-Jade C+ degenerated neurons, cleaved caspase 3+ neurons, and volume loss in the ipsilateral brain at P11. There was no sex-specific response to HI or insulin. The findings confirm that intranasal insulin provides neuroprotection against HI brain injury in P10 rats associated with activation of intracellular cell survival signaling. If further pre-clinical research shows long-term benefits, intranasal insulin has the potential to be a promising non-invasive therapy to improve outcomes for newborns with HIE.

The Use of Cerebral Near-Infrared Spectroscopy in Neonatal Hypoxic-Ischemic Encephalopathy: A Systematic Review of the Literature

BACKGROUND

Cerebral near-infrared spectroscopy (cNIRS) is a noninvasive technology used to trend cerebral perfusion at the bedside. cNIRS has potential as a valuable tool in the evaluation of infants with suspected hypoxic-ischemic encephalopathy (HIE). Trending cerebral perfusion with cNIRS can provide information regarding cerebral metabolism as HIE is evolving, which may offer insight into the extent of brain injury.

PURPOSE

The purpose of this systematic review is to investigate the use of cNIRS as a neurocritical tool in the management of neonatal HIE by evaluating its ability to detect acute neurological compromise, including acute brain injury and seizure activity, as well as its potential to identify infants at high risk for long-term neurodevelopmental impairment.

METHODS

A literature search was conducted using PubMed, CINAHL, and Web of Science databases to review articles investigating cNIRS technology in the acute management of HIE.

RESULTS

Eight studies were identified and included in this systematic review. Correlations were observed between cNIRS trends and neurological outcomes as later detected by MRI. cNIRS has potential as a bedside neuromonitoring tool in the management of HIE to detect infants at high risk for brain injury.

IMPLICATIONS FOR PRACTICE

Existing research supports the value of trending cNIRS in HIE management. Documented normal cNIRS values for both term and preterm infants in the first few days of life is approximately 60% to 80%. A steadily increasing cNIRS reading above an infant's baseline and a value of more than 90% should prompt further evaluation and concern for significant neurological injury.

Race and Ethnicity of Infants Enrolled in Neonatal Clinical Trials: A Systematic Review

Importance

Representativeness of populations within neonatal clinical trials is crucial to moving the field forward. Although racial and ethnic disparities in research inclusion are well documented in other fields, they are poorly described within neonatology.

Objective

To describe the race and ethnicity of infants included in a sample of recent US neonatal clinical trials and the variability in this reporting.

Evidence Review

A systematic search of US neonatal clinical trials entered into Cochrane CENTRAL 2017 to 2021 was conducted. Two individuals performed inclusion determination, data extraction, and quality assessment independently with discrepancies adjudicated by consensus.

Findings

Of 120 studies with 14 479 participants that met the inclusion criteria, 75 (62.5%) included any participant race or ethnicity data. In the studies that reported race and ethnicity, the median (IQR) percentage of participants of each background were 0% (0%-1%) Asian, 26% (9%-42%) Black, 3% (0%-12%) Hispanic, 0% (0%-0%) Indigenous (eg, Alaska Native, American Indian, and Native Hawaiian), 0% (0%-0%) multiple races, 57% (30%-68%) White, and 7% (1%-21%) other race or ethnicity. Asian, Black, Hispanic, and Indigenous participants were underrepresented, while White participants were overrepresented compared with a reference sample of the US clinical neonatal intensive care unit (NICU) population from the Vermont Oxford Network. Many participants were labeled as other race or ethnicity without adequate description. There was substantial variability in terms and methods of reporting race and ethnicity data. Geographic representation was heavily skewed toward the Northeast, with nearly one-quarter of states unrepresented.

Conclusions and Relevance

These findings suggest that neonatal research may perpetuate inequities by underrepresenting Asian, Black, Hispanic, and Indigenous neonates in clinical trials. Studies varied in documentation of race and ethnicity, and there was regional variation in the sites included. Based on these findings, funders and clinical trialists are advised to consider a 3-point targeted approach to address these issues: prioritize identifying ways to increase diversity in neonatal clinical trial participation, agree on a standardized method to report race and ethnicity among neonatal clinical trial participants, and prioritize the inclusion of participants from all regions of the US in neonatal clinical trials.

Short-term neurological injury in newborns infants with overcooling in passive hypothermia and transferred to reference hospital in Colombia

AIM

The aim of the study was to determine whether overcooling (temperature <33°C) during passive hypothermia when transporting neonates with perinatal asphyxia increased the risk of short-term neurological injury.

METHODS

A retrospective observational study was performed. Newborns transferred to the LaCardio neonatal unit between January 2021 and April 2022 with moderate and severe perinatal asphyxia and who received passive hypothermia during transport were included. A temperature of <33°C was considered overcooling. A composite outcome of neurological injury was defined by the presence of abnormalities on brain magnetic resonance imaging, video telemetry, seizure before discharge or both.

RESULTS

The study included 101 newborns. A total of 18 neonates had a temperature <33°C after transportation. Neurological injuries were present in 21.8% of the temperature <33°C group and 78.2% of the temperature ≥33°C group. Temperature <33°C at the end of transport (aOR 9.2, 95% CI 1.1-77.3) were associated with neurological injury before discharge from the unit.

CONCLUSION

During transportation, overcooling in neonates with asphyxia increases the risk of neurological injury before discharge from the neonatal unit. It is important to qualify the transport team with adequate training and equipment for therapeutic hypothermia.

Neuroserpin As an Adjuvant Therapy for Hypothermia on Brain Injury in Neonatal Hypoxic-Ischemic Rats

OBJECTIVE

 We aimed to assess the effects of neuroserpin and its combination with hypothermia on hypoxic-ischemic (HI) brain injury in neonatal rats. Neuroserpin is an axon-secreted serine protease inhibitor and is important for brain development, neuronal survival, and synaptic plasticity.

STUDY DESIGN

 Male Wistar-Albino rats on postnatal day 7 (P7) were randomly divided into five groups: sham group (n = 10), (HI; n = 10), hypoxic-ischemic hypothermia (HIH; n = 10), hypoxic-ischemic neuroserpin (HIN; n = 10), and hypoxic-ischemic neuroserpin-hypothermia (HINH; n = 10). The P7 rat brain's maturation is similar to a late preterm human brain at 34 to 36 weeks of gestation. HI was induced in rats on P7 as previously described. A single dose of 0.2 µM neuroserpin (HINH and HIN) or an equivalent volume of phosphate-buffered saline (sham, HIH, and HI) was administered intraventricularly by a Hamilton syringe immediately after hypoxia. In the follow-up, pups were subjected to systemic hypothermia or normothermia for 2 hours. Euthanasia was performed for histopathological evaluation on P10. Apoptosis was detected by caspase-3 activity and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining and was counted in the hippocampus.

RESULTS

 In comparison to the HI group, the TUNEL-positive and caspase-3-positive neurons in the sham, HIN, HIH, and HINH groups were considerably lower (13.4 ± 1.0 vs. 1.9 ± 0.9, 6.0 ± 0.9, 5.3 ± 1.6, and 4.0 ± 1.1; p < 0.001) and (13.5 ± 1.7 vs. 1.2 ± 0.7, 9.1 ± 2.7, 4.8 ± 1.0, and 3.9 ± 1.6; p < 0.001). HIN, HIH, and HINH, compared to the sham group, showed more TUNEL-positive and caspase-3-positive neurons (6.0 ± 0.9, 5.3 ± 1.6, 4.0 ± 1.1 vs. 1.9 ± 0.9 and 9.1 ± 2.7, 4.8 ± 1.0, 3.9 ± 1.6 vs. 1.2 ± 0.7; p < 0.001). The HINH group (synergistic effect) had significantly fewer TUNEL-positive neurons and caspase-3-positive neurons than the HIN group (4.0 ± 1.1vs. 6.0 ± 0.9 and 3.9 ± 1.6 vs. 9.1 ± 2.7; p < 0.001).

CONCLUSION

 Our study showed that both neuroserpin alone and as an adjuvant treatment for hypothermia may have a neuroprotective effect on brain injury.

KEY POINTS

· Neuroserpin decreased brain injury.. · Neuroserpin showed a synergistic effect when used as an adjuvant treatment for hypothermia.. · The neuroprotective effect of neuroserpine was related to its antiapoptotic properties..

Strengthening Reporting of Neonatal Trials

BACKGROUND AND OBJECTIVES

There is variability in the selection and reporting of outcomes in neonatal trials with key information frequently omitted. This can impact applicability of trial findings to clinicians, families, and caregivers, and impair evidence synthesis. The Neonatal Core Outcomes Set describes outcomes agreed as clinically important that should be assessed in all neonatal trials, and Consolidated Standards of Reporting Trials (CONSORT)-Outcomes 2022 is a new, harmonized, evidence-based reporting guideline for trial outcomes. We reviewed published trials using CONSORT-Outcomes 2022 guidance to identify exemplars of neonatal core outcome reporting to strengthen description of outcomes in future trial publications.

METHODS

Neonatal trials including >100 participants per arm published between 2015 to 2020 with a primary outcome included in the Neonatal Core Outcome Set were identified. Primary outcome reporting was reviewed using CONSORT 2010 and CONSORT-Outcomes 2022 guidelines by assessors recruited from Cochrane Neonatal. Examples of clear and complete outcome reporting were identified with verbatim text extracted from trial reports.

RESULTS

Thirty-six trials were reviewed by 39 assessors. Examples of good reporting for CONSORT 2010 and CONSORT-Outcomes 2022 criteria were identified and subdivided into 3 outcome categories: "survival," "short-term neonatal complications," and "long-term developmental outcomes" depending on the core outcomes to which they relate. These examples are presented to strengthen future research reporting.

CONCLUSIONS

We have identified examples of good trial outcome reporting. These illustrate how important neonatal outcomes should be reported to meet the CONSORT 2010 and CONSORT-Outcomes 2022 guidelines. Emulating these examples will improve the transmission of information relating to outcomes and reduce associated research waste.

Comparing Three Methods of Therapeutic Hypothermia Among Transported Neonates with Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) and associated multiorgan injury are significant causes of morbidity and mortality in term and near-term neonates. Therapeutic hypothermia (TH) is the current standard of care for neuroprotection in neonates with HIE. In our experience, the majority of babies born with HIE were found in nontertiary care facilities in our region, where effective methods of cooling during transport to tertiary care centers are desirable. Most centers initiate passive TH at referral hospitals, while active cooling is typically initiated during transport. The objective of this study was to evaluate the effectiveness of three methods of cooling during transport of neonates with HIE in southern Alberta. In this prospective cohort study, 186 neonates with HIE were transported between January 2013 and December 2021. Among the 186 neonates, 47 were passively cooled, 36 actively cooled with gel packs, and 103 cooled with a servo-controlled cooling device. The clinical characteristics were comparable for the three groups, with no difference in adverse events. Fifteen neonates (8%) died and 54 neonates (29%) suffered radiologically determined brain injury. Servo-controlled cooling was found to be superior to other methods in maintaining a target temperature without significant fluctuation during transport and with temperature in the target range on arrival at tertiary care facilities. The rate of overcooling was also lower in the servo-controlled group compared with other groups. There were no statistically significant differences between the groups in relation to mortality and brain MRI changes associated with HIE. Adjusting for GA, 10-minute Apgar score, base excess, HIE stage, and need for intubation during transport, passive cooling increased the odds of temperature fluctuation outside the range by 12-fold and gel pack cooling by 13-fold compared with servo-controlled cooling. The use of servo-controlled TH devices should be the preferred practice wherever feasible. (REB17-1334_REN3).

A narrative review on treatment strategies for neonatal hypoxic ischemic encephalopathy

Background and Objective

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of death and disability worldwide. Therapeutic hypothermia (TH) represents a significant achievement in the translation of scientific research to clinical application, but it is currently the only neuroprotective treatment for HIE. This review aims to revisit the use of TH for HIE and its longitudinal impact on patient outcomes to readers new to the field of HIE. We discuss how emerging therapies address the broader pathophysiology of injury progression in the neonatal brain days to years after HIE.

Methods

We included full articles and book chapters published in English on PubMed with references to "hypoxic ischemic encephalopathy", "birth asphyxia", "therapeutic hypothermia", or "neonatal encephalopathy". We limited our review to outcomes on term infants and to new therapeutics that are in the second phase of clinical trials.

Key Content and Findings

Despite the use of TH for HIE, mortality remains high. Analysis of longitudinal studies reveals a high incidence of ongoing disability even with the implementation of TH. New therapeutics addressing the secondary phase and the less understood tertiary phase of brain injury are in clinical trials as adjunctive treatments to TH to support additional neurological repair and regeneration.

Conclusions

TH successfully improves outcomes after HIE, and it continues to be optimized. Larger studies are needed to understand its use in mild cases of HIE and if certain factors, such as sex, affect long term outcomes. TH primarily acts in the initial phases of injury, while new pharmaceutical therapies target additional injury pathways into the tertiary phases of injury. This may allow for more effective approaches to treatment and improvement of long-term functional outcomes after HIE.

BOston Neonatal Brain Injury Dataset for Hypoxic Ischemic Encephalopathy (BONBID-HIE): Part I. MRI and Manual Lesion Annotation

Hypoxic ischemic encephalopathy (HIE) is a brain injury that occurs in 1 ~ 5/1000 term neonates. Accurate identification and segmentation of HIE-related lesions in neonatal brain magnetic resonance images (MRIs) is the first step toward predicting prognosis, identifying high-risk patients, and evaluating treatment effects. It will lead to a more accurate estimation of prognosis, a better understanding of neurological symptoms, and a timely prediction of response to therapy. We release the first public dataset containing neonatal brain diffusion MRI and expert annotation of lesions from 133 patients diagnosed with HIE. HIE-related lesions in brain MRI are often diffuse (i.e., multi-focal), and small (over half the patients in our data having lesions occupying <1% of brain volume). Segmentation for HIE MRI data is remarkably different from, and arguably more challenging than, other segmentation tasks such as brain tumors with focal and relatively large lesions. We hope that this dataset can help fuel the development of MRI lesion segmentation methods for HIE and small diffuse lesions in general.

Antiseizure medication at discharge in infants with hypoxic-ischaemic encephalopathy: an observational study

OBJECTIVES

To assess variability in continuation of antiseizure medication (ASM) at discharge and to evaluate if continuation of ASM at discharge is associated with death or disability among infants with hypoxic-ischaemic encephalopathy (HIE) and seizures.

DESIGN

Retrospective study of infants enrolled in three National Institute of Child Health and Human Development Neonatal Research Network Trials of therapeutic hypothermia.

SETTING

22 US centres.

PATIENTS

Infants with HIE who survived to discharge and had clinical or electrographic seizures treated with ASM.

EXPOSURES

ASM continued or discontinued at discharge.

OUTCOMES

Death or moderate-to-severe disability at 18-22 months, using trial definitions. Multivariable logistic regression evaluated the association between continuation of ASM at discharge and the primary outcome, adjusting for severity of HIE, hypothermia trial treatment arm, use of electroencephalogram, discharge on gavage feeds, Apgar Score at 5 min, birth year and centre.

RESULTS

Of 302 infants included, 61% were continued on ASMs at discharge (range 13%-100% among 22 centres). Electroencephalogram use occurred in 92% of the cohort. Infants with severe HIE comprised 24% and 22% of those discharged with and without ASM, respectively. The risk of death or moderate-to-severe disability was greater for infants continued on ASM at discharge, compared with those infants discharged without ASM (44% vs 28%, adjusted OR 2.14; 95% CI 1.13 to 4.05).

CONCLUSIONS

In infants with HIE and seizures, continuation of ASM at discharge varies substantially among centres and may be associated with a higher risk of death or disability at 18-22 months of age.

Temperature dysregulation during therapeutic hypothermia predicts long-term outcome in neonates with HIE

Few reliable or easily obtainable biomarkers to predict long-term outcome in infants with hypoxic-ischemic encephalopathy (HIE) have been identified. We previously showed that mattress temperature (MT), as proxy for disturbed temperature regulation during therapeutic hypothermia (TH), predicts injury on early MRI and holds promise as physiologic biomarker. To determine whether MT in neonates treated with TH for moderate-severe HIE is associated with long-term outcome at 18-22 months, we performed a secondary analysis of the Optimizing Cooling trial using MT data from 167 infants treated at a core temperature of 33.5°C. Median MTs from four time-epochs (0-6 h, 6-24 h, 24-48 h, and 48-72 h of TH) were used to predict death or moderate-severe neurodevelopmental impairment (NDI), using epoch-specific derived and validated MT cutoffs. Median MT of infants who died or survived with NDI was consistently 1.5-3.0°C higher throughout TH. Infants requiring a median MT above the derived cut-offs had a significantly increased odds of death or NDI, most notably at 0-6 h (aOR 17.0, 95%CI 4.3-67.4). By contrast, infants who remained below cut-offs across all epochs had 100% NDI-free survival. MTs in neonates with moderate-severe HIE during TH are highly predictive of long-term outcome and can be used as physiologic biomarker.

Extracellular vesicles from immortalized mesenchymal stromal cells protect against neonatal hypoxic-ischemic brain injury

BACKGROUND

Human mesenchymal stromal cell (MSC)-derived extracellular vesicles (EV) revealed neuroprotective potentials in various brain injury models, including neonatal encephalopathy caused by hypoxia-ischemia (HI). However, for clinical translation of an MSC-EV therapy, scaled manufacturing strategies are required, which is challenging with primary MSCs due to inter- and intra-donor heterogeneities. Therefore, we established a clonally expanded and immortalized human MSC line (ciMSC) and compared the neuroprotective potential of their EVs with EVs from primary MSCs in a murine model of HI-induced brain injury. In vivo activities of ciMSC-EVs were comprehensively characterized according to their proposed multimodal mechanisms of action.

METHODS

Nine-day-old C57BL/6 mice were exposed to HI followed by repetitive intranasal delivery of primary MSC-EVs or ciMSC-EVs 1, 3, and 5 days after HI. Sham-operated animals served as healthy controls. To compare neuroprotective effects of both EV preparations, total and regional brain atrophy was assessed by cresyl-violet-staining 7 days after HI. Immunohistochemistry, western blot, and real-time PCR were performed to investigate neuroinflammatory and regenerative processes. The amount of peripheral inflammatory mediators was evaluated by multiplex analyses in serum samples.

RESULTS

Intranasal delivery of ciMSC-EVs and primary MSC-EVs comparably protected neonatal mice from HI-induced brain tissue atrophy. Mechanistically, ciMSC-EV application reduced microglia activation and astrogliosis, endothelial activation, and leukocyte infiltration. These effects were associated with a downregulation of the pro-inflammatory cytokine IL-1 beta and an elevated expression of the anti-inflammatory cytokines IL-4 and TGF-beta in the brain, while concentrations of cytokines in the peripheral blood were not affected. ciMSC-EV-mediated anti-inflammatory effects in the brain were accompanied by an increased neural progenitor and endothelial cell proliferation, oligodendrocyte maturation, and neurotrophic growth factor expression.

CONCLUSION

Our data demonstrate that ciMSC-EVs conserve neuroprotective effects of primary MSC-EVs via inhibition of neuroinflammation and promotion of neuroregeneration. Since ciMSCs can overcome challenges associated with MSC heterogeneity, they appear as an ideal cell source for the scaled manufacturing of EV-based therapeutics to treat neonatal and possibly also adult brain injury.

Severity and duration of dysglycemia and brain injury among patients with neonatal encephalopathy

Background

Evidence is needed to inform thresholds for glycemic management in neonatal encephalopathy (NE). We investigated how severity and duration of dysglycemia relate to brain injury after NE.

Methods

A prospective cohort of 108 neonates ≥36 weeks gestational age with NE were enrolled between August 2014 and November 2019 at the Hospital for Sick Children, in Toronto, Canada. Participants underwent continuous glucose monitoring for 72 h, MRI at day 4 of life, and follow-up at 18 months. Receiver operating characteristic curves were used to assess the predictive value of glucose measures (minimum and maximum glucose, sequential 1 mmol/L glucose thresholds) during the first 72 h of life (HOL) for each brain injury pattern (basal ganglia, watershed, focal infarct, posterior-predominant). Linear and logistic regression analyses were used to assess the relationship between abnormal glycemia and 18-month outcomes (Bayley-III composite scores, Child Behavior Checklist [CBCL] T-scores, neuromotor score, cerebral palsy [CP], death), adjusting for brain injury severity.

Findings

Of 108 neonates enrolled, 102 (94%) had an MRI. Maximum glucose during the first 48 HOL best predicted basal ganglia (AUC = 0.811) and watershed (AUC = 0.858) injury. Minimum glucose was not predictive of brain injury (AUC <0.509). Ninety-one (89%) infants underwent follow-up assessments at 19.0 ± 1.7 months. A glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with 5.8-point higher CBCL Internalizing Composite T-score (P = 0.029), 0.3-point worse neuromotor score (P = 0.035), 8.6-fold higher odds for CP diagnosis (P = 0.014). While the glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with higher odds of the composite outcome of severe disability or death (OR 3.0, 95% CI 1.0-8.4, P = 0.042), it was not associated with the composite outcome of moderate-to-severe disability or death (OR 0.9, 95% CI 0.4-2.2, P = 0.801). All associations with outcome lost significance after adjusting for brain injury severity.

Interpretation

Maximum glucose concentration in the first 48 HOL is predictive of brain injury after NE. Further trials are needed to assess if protocols to control maximum glucose concentrations improve outcomes after NE.

Funding

Canadian Institutes for Health Research, National Institutes of Health, and SickKids Foundation.

The role of early functional neuroimaging in predicting neurodevelopmental outcomes in neonatal encephalopathy

Reliably assessing the early neurodevelopmental outcomes in infants with neonatal encephalopathy (NE) is of utmost importance to advise parents and implement early and personalized interventions. We aimed to evaluate the accuracy of neuroimaging modalities, including functional magnetic resonance imaging (fMRI) in predicting neurodevelopmental outcomes in NE. Eighteen newborns with NE due to presumed perinatal asphyxia (PA) were included in the study, 16 of whom underwent therapeutic hypothermia. Structural magnetic resonance imaging (MRI), and fMRI during passive visual, auditory, and sensorimotor stimulation were acquired between the 10th and 14th day of age. Clinical follow-up protocol included visual and auditory evoked potentials and a detailed neurodevelopmental evaluation at 12 and 18 months of age. Infants were divided according to sensory and neurodevelopmental outcome: severe, moderate disability, or normal. Structural MRI findings were the best predictor of severe disability with an AUC close to 1.0. There were no good predictors to discriminate between moderate disability versus normal outcome. Nevertheless, structural MRI measures showed a significant correlation with the scores of neurodevelopmental assessments. During sensorimotor stimulation, the fMRI signal in the right hemisphere had an AUC of 0.9 to predict absence of cerebral palsy (CP). fMRI measures during auditory and visual stimulation did not predict sensorineural hearing loss or cerebral visual impairment.

CONCLUSION

In addition to structural MRI, fMRI with sensorimotor stimulation may open the gate to improve the knowledge of neurodevelopmental/motor prognosis if proven in a larger cohort of newborns with NE.

WHAT IS KNOWN

• Establishing an early, accurate neurodevelopmental prognosis in neonatal encephalopathy remains challenging. • Although structural MRI has a central role in neonatal encephalopathy, advanced MRI modalities are gradually being explored to optimize neurodevelopmental outcome knowledge.

WHAT IS NEW

• Newborns who later developed cerebral palsy had a trend towards lower fMRI measures in the right sensorimotor area during sensorimotor stimulation. • These preliminary fMRI results may improve future early delineation of motor prognosis in neonatal encephalopathy.

The Feasibility of Telemedicine in the Implementation and Management of Therapeutic Hypothermia for Infants with Neonatal Hypoxic-Ischemic Encephalopathy in a Resource-Limited Country

Background Telemedicine is widely used in neonatal services in developed countries, though its outcomes in low- and middle-income countries are controversial. Lack of expertise and/or facilities, however, has limited its use in developing countries and around areas of military conflicts. We aim to study the implementation and management of therapeutic hypothermia (TH) in infants with hypoxic-ischemic encephalopathy (HIE) with the help of telemedicine in a resource-limited country.

Methodology This is a retrospective study, evaluating patients who received TH, guided by telemedicine, through a mobile app (Telegram), an application that allows sharing and archiving of information with other beneficial features. We assessed the feasibility of utilizing telemedicine in guiding the application of TH to infants affected with HIE in the North-West of Syria between July 2020 and July 2021. Feasibility was measured by parameters related to the time gaps between initiation of consultation and treatment and clinical short-term outcomes.

Results Out of 5,545 newborn infants delivered during the study period, 22 patients were eligible for TH guided by telemedicine. Patients were referred for consultation at a median (interquartile range [IQR]) of 137 (35–165) minutes of life. A median (IQR) of 12 (3–18) minutes elapsed between the call for a consultation and the consultant response and a median (IQR) of 30 (0–42) minutes elapsed between seeking the consultation and the initiation of cooling therapy. Eighteen patients completed cooling for 72 hours. The patients' temperatures were within the target range (33–34°C) most of the time (84.1%).

Conclusion Telemedicine is a feasible method to guide the implementation TH for HIE in resource-limited areas. The short-term success rate is relatively high; however, further studies with a larger population are needed to confirm these findings.

Therapeutic Hypothermia Attenuates Cortical Interneuron Loss after Cerebral Ischemia in Near-Term Fetal Sheep

Therapeutic hypothermia significantly improves outcomes after neonatal hypoxic-ischemic (HI) encephalopathy but is only partially protective. There is evidence that cortical inhibitory interneuron circuits are particularly vulnerable to HI and that loss of interneurons may be an important contributor to long-term neurological dysfunction in these infants. In the present study, we examined the hypothesis that the duration of hypothermia has differential effects on interneuron survival after HI. Near-term fetal sheep received sham ischemia or cerebral ischemia for 30 min, followed by cerebral hypothermia from 3 h after ischemia end and continued up to 48 h, 72 h, or 120 h recovery. Sheep were euthanized after 7 days for histology. Hypothermia up to 48 h recovery resulted in moderate neuroprotection of glutamate decarboxylase (GAD)⁺ and parvalbumin⁺ interneurons but did not improve survival of calbindin⁺ cells. Hypothermia up to 72 h recovery was associated with significantly increased survival of all three interneuron phenotypes compared with sham controls. By contrast, while hypothermia up to 120 h recovery did not further improve (or impair) GAD⁺ or parvalbumin⁺ neuronal survival compared with hypothermia up to 72 h, it was associated with decreased survival of calbindin⁺ interneurons. Finally, protection of parvalbumin⁺ and GAD⁺ interneurons, but not calbindin⁺ interneurons, with hypothermia was associated with improved recovery of electroencephalographic (EEG) power and frequency by day 7 after HI. The present study demonstrates differential effects of increasing the duration of hypothermia on interneuron survival after HI in near-term fetal sheep. These findings may contribute to the apparent preclinical and clinical lack of benefit of very prolonged hypothermia.

Therapeutic hypothermia demonstrates sex-dependent improvements in motor function in a rat model of neonatal hypoxic ischemic encephalopathy

Neonatal hypoxic ischemic encephalopathy (HIE) is a neurological disease caused by restricted oxygen and blood flow to the brain at or around the time of birth. Long term cognitive and motor sequelae are common and demonstrate sexual dimorphism in animal studies. Therapeutic hypothermia (TH) is the standard of care for HIE, but provides incomplete neuroprotection. Using the Vannucci model of neonatal HIE, term-equivalent 11-day old rat pups were subjected to mild-moderate hypoxic-ischemic injury (HII), and a subset of animals were treated with TH. Sex-dependent neuroprotection was measured with gross and fine motor control assays, and functional deficits detected with these assays were correlated to injury in specific brain structures. At the equivalent of human adolescence and adulthood (P51-89), accelerod and beam walking tests were used to assess gross motor function, and string-pulling and food handling tests were used to assess fine motor function. At necropsy (P94-97), brain lesions were primarily focused to the posterior cerebrum and characterized by variable reduction in cortical, thalamic and hippocampal regions and glial scarring. Gross motor impairment was detected in male rats with untreated and TH-treated HIE in the accelerod test, but beam walk test data was confounded by the lower body mass of untreated male rats. HIE animals of both sexes demonstrated deficit in the forelimb contralateral to ischemic surgery, observed as unilaterally impaired food handling behaviors, and in string pulling as decreased string contacts and increased in bracing behavior. However, kinematic analyses revealed sex-specific decreases in peak speeds in string reaching and pulling movements. In both sexes, treatment with TH improved body mass, some measures of contralateral forelimb impairment, and the severity of brain lesions to levels not different to Sham surgery rats. Unique differences in behavior following TH were observed in female rats, who took longer to consume food items but traversed beams and approached strings faster than untreated and Sham females. Future use of these motor assays may unravel the subtle, sex-specific differences in HIE outcomes and in developing a customized therapeutic approach to neonatal brain injury.

Interleukin-1: an important target for perinatal neuroprotection?

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.

Therapeutic hypothermia as a neuroprotective strategy in newborns with perinatal asphyxia-case report

Background

Perinatal asphyxia is a public health problem and the third major cause of death among children under 5 years.

Objective

Two clinical cases of newborns with perinatal asphyxia submitted to therapeutic hypothermia and the follow-up of their motor development after hospital discharge have been reported.

Methods

This retrospective case report study included two newborns with hypoxic-ischemic encephalopathy due to perinatal asphyxia who received a hypothermia protocol at the neonatal intensive care unit (NICU). The two newborns and their families were followed up at the outpatient clinic and assessed using the Hammersmith Child Neurological Examination, Alberta Child Motor Scale, and Denver Developmental Screening Test-II.

Results

The newborns were submitted to a 72-hour hypothermia protocol. One newborn remained for 13 days in the NICU, while the other remained for 22 days. According to the multidisciplinary team, both cases presented with typical motor development with no cerebral palsy during the follow-up.

Conclusion

Both cases showed positive results and a good prognostic for motor development. Therapeutic hypothermia may be a strategy to prevent neurologic sequelae in newborns with perinatal asphyxia, including cerebral palsy.

N-Acetylcysteine Administration Attenuates Sensorimotor Impairments Following Neonatal Hypoxic-Ischemic Brain Injury in Rats

Hypoxic ischemic (HI) brain injury that occurs during neonatal period has been correlated with severe neuronal damage, behavioral deficits and infant mortality. Previous evidence indicates that N-acetylcysteine (NAC), a compound with antioxidant action, exerts a potential neuroprotective effect in various neurological disorders including injury induced by brain ischemia. The aim of the present study was to investigate the role of NAC as a potential therapeutic agent in a rat model of neonatal HI brain injury and explore its long-term behavioral effects. To this end, NAC (50 mg/kg/dose, i.p.) was administered prior to and instantly after HI, in order to evaluate hippocampal and cerebral cortex damage as well as long-term functional outcome. Immunohistochemistry was used to detect inducible nitric oxide synthase (iNOS) expression. The results revealed that NAC significantly alleviated sensorimotor deficits and this effect was maintained up to adulthood. These improvements in functional outcome were associated with a significant decrease in the severity of brain damage. Moreover, NAC decreased the short-term expression of iNOS, a finding implying that iNOS activity may be suppressed and that through this action NAC may exert its therapeutic action against neonatal HI brain injury.

Trends of neonatal hypoxic-ischemic encephalopathy prevalence and associated risk factors in the United States, 2010 to 2018

BACKGROUND

Despite recent advances in perinatal care, neonatal hypoxic-ischemic encephalopathy remains one of the most common causes of neonatal morbidity and mortality. The trends for prevalence and mortality of neonatal hypoxic-ischemic encephalopathy have not been examined in the era of therapeutic hypothermia in the United States.

OBJECTIVE

This study aimed to determine (1) the overall and gestational age-specific (35-36, ≥37, and >42 weeks) trends of hypoxic-ischemic encephalopathy prevalence and use of therapeutic hypothermia, (2) the trends of mortality in association with hypoxic-ischemic encephalopathy, (3) the confounding variables associated with hypoxic-ischemic encephalopathy, and (4) the clinical outcomes of neonates with hypoxic-ischemic encephalopathy.

STUDY DESIGN

This study used National Inpatient Sample datasets from 2010 to 2018. Moreover, the study included infants with a gestational age of ≥35 weeks with a documented hypoxic-ischemic encephalopathy diagnosis (mild, moderate, severe, or unspecified). We calculated trends in hypoxic-ischemic encephalopathy prevalence and the use of therapeutic hypothermia using chi-squared testing. Furthermore, this study used logistic regression models to control for confounders.

RESULTS

A total of 32,180,617 infants were included, of which 31,249,100 were term (gestational age of ≥37 weeks) and 931,517 were late preterm (gestational age of 35-36 weeks). Hypoxic-ischemic encephalopathy prevalence slightly increased from 0.093% in 2010-2012 to 0.097% in 2016-2018 (P=.01) in term infants and did not significantly change in late preterm infants (P=.20). There were 6235 term infants (20.8%) and 449 late preterm infants (21.1%) with hypoxic-ischemic encephalopathy who were managed with therapeutic hypothermia. The use of therapeutic hypothermia in both term and late preterm infants has increased over the years (P<.01). The mortality rate with hypoxic-ischemic encephalopathy decreased over time from 11.5% to 12.3% between 2010 to 2012, and from 8.3% to 10.6% betweenn 2016 to 2018 (P<.01). The factors with the strongest association with hypoxic-ischemic encephalopathy were placental infarction or insufficiency (odds ratio, 144; 95% confidence interval, 134-157), placental abruption (odds ratio, 101; 95% confidence interval, 91-112), cord prolapse (odds ratio, 74; 95% confidence interval, 65-84), and maternal anemia (odds ratio, 26; 95% confidence interval, 20-37).

CONCLUSION

Hypoxic-ischemic encephalopathy prevalence in neonates essentially remained the same at 1 per 1000 live births. The use of therapeutic hypothermia increased, and the mortality rate decreased in infants with hypoxic-ischemic encephalopathy. The identification of hypoxic-ischemic encephalopathy-associated factors should promote increased vigilance to optimize newborn outcomes.

Overview of the neonatal research network: History, contributions, challenges, and future

The Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network (NRN) has been a leader in neonatal research since 1986. In this chapter we review its history and achievements in (1) continuing observation of populations, treatments, short and longer-term outcomes, and trends over time; (2) "negative studies" (trials with non-significant primary outcomes) and trials stopped for futility or adverse events, which have influenced practice and subsequent trial design; and, (3) landmark trials that have changed neonatal care. Its consistent framework has enabled the NRN to be a pioneer in conducting longer-term, school-age follow-up. Leveraging its established infrastructure, the NRN has also partnered with other NIH institutes, governmental agencies, and industry to more effectively advance neonatal care. As current examples of its evolution with changing times, the Network has instituted a process to open specific network trials to external institutions and is adding a parent and participant component to future endeavors.

Outcome prediction in newborn infants: Past, present, and future

The perinatal and neonatal periods are the periods of considerable organ development and maturation. Perinatal and neonatal illnesses can result in mortality and morbidities that burden families and the healthcare system. Outcome prediction is essential for informing perinatal and intensive care management, prognosis, and post-discharge interventions. The Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network (NRN) research databases include hospital and neurodevelopment follow-up outcomes of infants with various underlying diseases and conditions receiving intensive care, providing a unique opportunity to assess outcome risk prediction. The NRN has developed outcome risk prediction tools for use in infants with various diseases and conditions that allow data-driven, transparent discussions to inform family-focused communications and clinical management. This review presents the published neonatal outcome risk prediction research from the NRN, their present clinical utility, and possible future directions for advanced individualized risk prediction.

Neuroprotection for hypoxic-ischemic encephalopathy: Contributions from the neonatal research network

Therapeutic hypothermia (TH) is now well established as the standard of care treatment for moderate to severe neonatal encephalopathy secondary to perinatal hypoxic ischemic encephalopathy (HIE) in infants ≥36 weeks gestation in high income countries. The Neonatal Research Network (NRN) contributed greatly to the study of TH as a neuroprotectant with three trials now completed in infants ≥36 weeks gestation and the only large randomized-controlled trial of TH in preterm infants now in the follow-up phase. Data from the first NRN TH trial combined with data from other large trials of TH affirm the safety and neuroprotective qualities of TH and highlight the importance of providing TH to all infants who qualify. In this review we will highlight the findings of the three NRN trials of TH in the term infant population and the secondary analyses that continue to inform the care of patients with HIE.

Risk factors for unfavorable outcome at discharge of newborns with hypoxic-ischemic encephalopathy in the era of hypothermia

OBJECTIVE

To re-visit short-term outcomes and associated risk factors of newborns with hypoxic-ischemic encephalopathy (HIE) in an era where hypothermia treatment (HT) is widespread.

METHODS

This is a prospective population-based cohort in French neonatal intensive care units (NICU). Neonates born at or after 34 weeks of gestational age with HIE were included; main outcomes were in-hospital death and discharge with abnormal or normal MRI. Associations of early perinatal risk factors, present at birth or at admission to NICU, with these outcomes were studied.

RESULTS

A total of 794 newborns were included and HT was administered to 670 (84.4%); 18.3% died and 28.5% and 53.2% survived with abnormal and normal MRI, respectively. Severe neurological status, Apgar score at 5 mn ≤5, lactate at birth ≥11 mMoles/l, and glycemia ≥100 mg/dL at admission were associated with an increased risk of death (relative risk ratios (aRRR) (95% CI) 19.93 (10.00-39.70), 2.89 (1.22-1.62), 3.06 (1.60-5.83), and 2.55 (1.38-4.71), respectively). Neurological status only was associated with survival with abnormal MRI (aRRR (95% CI) 1.76 (1.15-2.68)).

CONCLUSION

Despite high use of HT in this cohort, 46.8% died or presented brain lesions. Early neurological and biological examinations were associated with unfavorable outcomes and these criteria could be used to target children who warrant further neuroprotective treatment.

TRIAL REGISTRATION

Clinical trial registry, NCT02676063, ClinicalTrials.gov.

IMPACT

In this population-based cohort of newborns with HIE where 84% received hypothermia, 46.8% still had an unfavorable evolution (death or survival with abnormal MRI). Risk factors for death were high lactate, low Apgar score, severe early neurological examination, and high glycaemia. While studies have established risk factors for HIE, few have focused on early perinatal factors associated with short-term prognosis. This French population-based cohort updates knowledge about early risk factors for adverse outcomes in the era of widespread cooling. In the future, criteria associated with an unfavorable evolution could be used to target children who would benefit from another neuroprotective strategy with hypothermia.

Neuroprotective therapies in the NICU in term infants: present and future

Outcomes of neonatal encephalopathy (NE) have improved since the widespread implementation of therapeutic hypothermia (TH) in high-resource settings. While TH for NE in term and near-term infants has proven beneficial, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. There is therefore a critical need to find additional pharmacological and non-pharmacological interventions that improve the outcomes for these children. There are many potential candidates; however, it is unclear whether these interventions have additional benefits when used with TH. Although primary and delayed (secondary) brain injury starting in the latent phase after HI are major contributors to neurodisability, the very late evolving effects of tertiary brain injury likely require different interventions targeting neurorestoration. Clinical trials of seizure management and neuroprotection bundles are needed, in addition to current trials combining erythropoietin, stem cells, and melatonin with TH. IMPACT: The widespread use of therapeutic hypothermia (TH) in the treatment of neonatal encephalopathy (NE) has reduced the associated morbidity and mortality. However, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. This review details the pathophysiology of NE along with the evidence for the use of TH and other beneficial neuroprotective strategies used in term infants. We also discuss treatment strategies undergoing evaluation at present as potential adjuvant treatments to TH in NE.

Antiapoptotic Effects of Hydroxychloroquine on Hypoxic-Ischemic Injury in Neonatal Rat Brain: May Hydroxychloroquine Be an Adjuvant Theraphy?

OBJECTIVE

 Hydroxychloroquine (HCQ) has immunomodulatory, antithrombotic, cardiovascular, antimicrobial, and antineoplastic effects. In this study, we aimed to investigate the antiapoptotic and immunomodulator effects of intraperitoneal HCQ on hypoxic-ischemic (HI) injury in newborn rats.

STUDY DESIGN

 Wistar albino rats, 7 to 10 days old, were randomly divided into three groups: hypoxic-ischemic encephalopathy (HIE) group, HIE treated with HCQ group, and Sham group. Left common carotid artery ligation and hypoxia model were performed in HIE and HCQ groups. The HCQ group was treated with 80 mg/kg intraperitoneal HCQ every 24 hours for 3 days, while Sham and HIE groups were given physiological saline. After 72 hours, rats were decapitated and brain tissues were stained with hematoxylin and eosin, TUNEL, and IL-1β for histopathological grading and neuronal cell injury.

RESULTS

 Neuronal apoptosis was statistically lower in all neuroanatomical areas in the HCQ group compared with the HIE group. IL-1β-stained areas were similar in both HCQ and HIE groups but significantly higher compared with the Sham group. Histopathological grading scores were found to be lower in the HCQ group on the left parietal cortex and hippocampus region.

CONCLUSION

 In this study, we have shown for the first time that HCQ treatment decreased apoptosis in HI newborn rat model in both hemispheres. HCQ may be a promising adjuvant therapy in neonatal HIE.

KEY POINTS

· HCQ decreased neuronal apoptosis in the ischemic penumbra of the rat brain.. · HCQ attenuates hypoxia-ischemia-induced brain injury in neonatal rats.. · HCQ has no anti-inflammatory effect on HI injury..

Targeting Persistent Neuroinflammation after Hypoxic-Ischemic Encephalopathy-Is Exendin-4 the Answer?

Hypoxic-ischemic encephalopathy is brain injury resulting from the loss of oxygen and blood supply around the time of birth. It is associated with a high risk of death or disability. The only approved treatment is therapeutic hypothermia. Therapeutic hypothermia has consistently been shown to significantly reduce the risk of death and disability in infants with hypoxic-ischemic encephalopathy. However, approximately 29% of infants treated with therapeutic hypothermia still develop disability. Recent preclinical and clinical studies have shown that there is still persistent neuroinflammation even after treating with therapeutic hypothermia, which may contribute to the deficits seen in infants despite treatment. This suggests that potentially targeting this persistent neuroinflammation would have an additive benefit in addition to therapeutic hypothermia. A potential additive treatment is Exendin-4, which is a glucagon-like peptide 1 receptor agonist. Preclinical data from various in vitro and in vivo disease models have shown that Exendin-4 has anti-inflammatory, mitochondrial protective, anti-apoptotic, anti-oxidative and neurotrophic effects. Although preclinical studies of the effect of Exendin-4 in perinatal hypoxic-ischemic brain injury are limited, a seminal study in neonatal mice showed that Exendin-4 had promising neuroprotective effects. Further studies on Exendin-4 neuroprotection for perinatal hypoxic-ischemic brain injury, including in large animal translational models are warranted to better understand its safety, window of opportunity and effectiveness as an adjunct with therapeutic hypothermia.

Hospital and Neurodevelopmental Outcomes in Nano-Preterm Infants Receiving Invasive vs Noninvasive Ventilation at Birth

IMPORTANCE

Infants with gestational age between 22 0/7 and 23 6/7 weeks (referred to as nano-preterm infants) are at very high risk of adverse outcomes. Noninvasive respiratory support at birth improves outcomes in infants born at 24 0/7 to 27 6/7 weeks' gestational age. Evidence is limited on whether similar benefits of non-invasive respiratory support at birth extend to nano-preterm infants.

OBJECTIVE

To evaluate the hypothesis that intubation at 10 minutes or earlier after birth is associated with a higher incidence of bronchopulmonary dysplasia (BPD) or death by 36 weeks' postmenstrual age (PMA) in nano-preterm infants.

DESIGN, SETTING, AND PARTICIPANTS

This observational cohort study included all nano-preterm infants at a level IV neonatal intensive care unit who were delivered from January 1, 2014, to June 30, 2021. Infants receiving palliative or comfort care at birth were excluded.

EXPOSURES

Infants were grouped based on first intubation attempt timing after birth (>10 minutes after birth and ≤10 minutes as noninvasive and invasive respiratory support at birth groups, respectively).

MAIN OUTCOMES AND MEASURES

The primary outcome was the composite outcome of BPD (physiological definition) or death by 36 weeks' PMA.

RESULTS

All 230 consecutively born, eligible nano-preterm infants were included, of whom 88 (median [IQR] gestational age, 23.6 [23.4-23.7] weeks; 45 [51.1%] female; 54 [62.1%] Black) were in the noninvasive respiratory support at birth group and 142 (median [IQR] gestational age, 23.0 [22.4-23.3] weeks; 71 [50.0%] female; 94 [66.2%] Black) were in the invasive respiratory support at birth group. The incidence of BPD or death by 36 weeks' PMA did not differ between the noninvasive and invasive respiratory support groups (83 of 88 [94.3%] in the noninvasive group vs 129 of 142 [90.9%] in the invasive group; adjusted odds ratio, 2.09; 95% CI, 0.60-7.25; P = .24). Severe intraventricular hemorrhage or death by 36 weeks' PMA was lower in the invasive respiratory support at birth group (adjusted odds ratio, 2.20; 95% CI, 1.07-4.51; P = .03).

CONCLUSIONS AND RELEVANCE

This cohort study's findings suggest that noninvasive respiratory support in the first 10 minutes after birth is feasible but is not associated with a decrease in the risk of BPD or death compared with intubation and early surfactant delivery in nano-preterm infants.

Neonatal encephalopathy plasma metabolites are associated with neurodevelopmental outcomes

BACKGROUND

To investigate mechanisms of injury and recovery in neonatal encephalopathy (NE), we performed targeted metabolomic analysis of plasma using liquid chromatography with tandem mass spectrometry (LC/MS/MS) from healthy term neonates or neonates with NE.

METHODS

Plasma samples from the NE (n = 45, day of life 0-1) or healthy neonatal (n = 30, ≥36 weeks gestation) cohorts had LC/MS/MS metabolomic profiling with a 193-plex targeted metabolite assay covering >366 metabolic pathways. Metabolite levels were compared to 2-year neurodevelopmental outcomes measured by the Bayley Scales of Infant and Toddler Development III (Bayley-III).

RESULTS

Out of 193 metabolites, 57 met the pre-defined quality control criteria for analysis. Significant (after false discovery rate correction) KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways included aminoacyl-tRNA biosynthesis, arginine biosynthesis, and metabolism of multiple amino acids. Significant disease pathways included seizures. In regression models, histidine and C6 sugar amine were significantly associated with cognitive, motor, and language and betaine with cognitive and motor Bayley-III composite scores. The addition of histidine, C6 sugar amine, and betaine to a Sarnat score-based clinical regression model significantly improved model performance (Akaike information criterion and adjusted r²) for Bayley-III cognitive, motor, and language scores.

CONCLUSIONS

Plasma metabolites may help to predict neurological outcomes in neonatal brain injury and enhance current clinical predictors.

IMPACT

Plasma metabolites may help to predict neurological outcomes in NE and supplement current clinical predictors. Current metabolomics research is limited in terms of clinical application and association with long-term outcomes. Our study presents novel associations of plasma metabolites from the first 24 h of life and 2-year neurodevelopmental outcomes for infants with NE. Our metabolomics discovery provides insight into possible disease mechanisms and methods to rescue and/or supplement metabolic pathways involved in NE. Our metabolomics discovery of metabolic pathway supplementations and/or rescue mechanisms may serve as adjunctive therapies for NE.

Persistent cortical and white matter inflammation after therapeutic hypothermia for ischemia in near-term fetal sheep

Background

Therapeutic hypothermia significantly improves outcomes after moderate–severe hypoxic-ischemic encephalopathy (HIE), but it is partially effective. Although hypothermia is consistently associated with reduced microgliosis, it is still unclear whether it normalizes microglial morphology and phenotype.

Methods

Near-term fetal sheep (n = 24) were randomized to sham control, ischemia-normothermia, or ischemia-hypothermia. Brain sections were immunohistochemically labeled to assess neurons, microglia and their interactions with neurons, astrocytes, myelination, and gitter cells (microglia with cytoplasmic lipid granules) 7 days after cerebral ischemia. Lesions were defined as areas with complete loss of cells. RNAscope^® was used to assess microglial phenotype markers CD86 and CD206.

Results

Ischemia-normothermia was associated with severe loss of neurons and myelin (p < 0.05), with extensive lesions, astrogliosis and microgliosis with a high proportion of gitter cells (p < 0.05). Microglial wrapping of neurons was present in both the ischemia groups. Hypothermia improved neuronal survival, suppressed lesions, gitter cells and gliosis (p < 0.05), and attenuated the reduction of myelin area fraction. The “M1” marker CD86 and “M2” marker CD206 were upregulated after ischemia. Hypothermia partially suppressed CD86 in the cortex only (p < 0.05), but did not affect CD206.

Conclusions

Hypothermia prevented lesions after cerebral ischemia, but only partially suppressed microglial wrapping and M1 marker expression. These data support the hypothesis that persistent upregulation of injurious microglial activity may contribute to partial neuroprotection after hypothermia, and that immunomodulation after rewarming may be an important therapeutic target.

Hypothermia after Perinatal Asphyxia Does Not Affect Genes Responsible for Amyloid Production in Neonatal Peripheral Lymphocytes

In this study, the expression of the genes of the amyloid protein precursor, β-secretase, presenilin 1 and 2 by RT-PCR in the lymphocytes of newborns after perinatal asphyxia and perinatal asphyxia treated with hypothermia was analyzed at the age of 15-21 days. The relative quantification of Alzheimer's-disease-related genes was first performed by comparing the peripheral lymphocytes of non-asphyxia control versus those with asphyxia or asphyxia with hypothermia. In the newborns who had perinatal asphyxia, the peripheral lymphocytes presented a decreased expression of the amyloid protein precursor and β-secretase genes. On the other hand, the expression of the presenilin 1 and 2 genes increased in the studied group. The expression of the studied genes in the asphyxia group treated with hypothermia had an identical pattern of changes that were not statistically significant to the asphyxia group. This suggests that the expression of the genes involved in the metabolism of the amyloid protein precursor in the peripheral lymphocytes may be a biomarker of progressive pathological processes in the brain after asphyxia that are not affected by hypothermia. These are the first data in the world showing the role of hypothermia in the gene changes associated with Alzheimer's disease in the peripheral lymphocytes of newborns after asphyxia.

Regulation of glutamate transport and neuroinflammation in a term newborn rat model of hypoxic–ischaemic brain injury

In the newborn brain, moderate-severe hypoxia–ischaemia induces glutamate excitotoxicity and inflammation, possibly via dysregulation of candidate astrocytic glutamate transporter ( Glt1) and pro-inflammatory cytokines (e.g. Tnfα, Il1β, Il6). Epigenetic mechanisms may mediate dysregulation. Hypotheses: (1) hypoxia–ischaemia dysregulates mRNA expression of these candidate genes; (2) expression changes in Glt1 are mediated by DNA methylation changes; and (3) methylation values in brain and blood are correlated. Seven-day-old rat pups ( n = 42) were assigned to nine groups based on treatment (for each timepoint: naïve ( n = 3), sham ( n = 3), hypoxia–ischaemia ( n = 8) and timepoint for tissue collection (6, 12 and 24 h post-hypoxia). Moderate hypoxic–ischemic brain injury was induced via ligation of the left common carotid artery followed by 100 min hypoxia (8% O2, 36°C). mRNA was quantified in cortex and hippocampus for the candidate genes, myelin ( Mbp), astrocytic ( Gfap) and neuronal ( Map2) markers (qPCR). DNA methylation was measured for Glt1 in cortex and blood (bisulphite pyrosequencing). Hypoxia–ischaemia induced pro-inflammatory cytokine upregulation in both brain regions at 6 h. This was accompanied by gene expression changes potentially indicating onset of astrogliosis and myelin injury. There were no significant changes in expression or promoter DNA methylation of Glt1. This pilot study supports accumulating evidence that hypoxia–ischaemia causes neuroinflammation in the newborn brain and prioritises further expression and DNA methylation analyses focusing on this pathway. Epigenetic blood biomarkers may facilitate identification of high-risk newborns at birth, maximising chances of neuroprotective interventions.

Three-year outcome following neonatal encephalopathy in a high-survival cohort

This study investigated the 3-year clinical outcomes in relation to the severity of encephalopathy in high-survival infants who underwent therapeutic hypothermia. This retrospective observational study was conducted in level II/III neonatal intensive care units in Japan. The nationwide cohort included 474 infants registered in the Baby Cooling Registry of Japan between January 2012 and December 2016. Clinical characteristics, mortality rate and severe neurological impairment at age 3 years were evaluated. Of the infants, 48 (10.4%), 291 (63.1%) and 122 (26.5%) had mild, moderate and severe encephalopathy, respectively, upon admission. By age 3, 53 (11.2%) infants died, whereas 110 (26.1%) developed major disabilities. The mild group survived up to age 3. In the moderate group, 13 (4.5%) died and 44 (15.8%) developed major disabilities. In the severe group, 39 (32.0%) died by age 3. Adverse outcomes were observed in 100 (82.0%) infants. Mortality was relatively low in all subgroups, but the incidence of major disabilities was relatively high in the severe group. The relatively low mortality and high morbidity may be due to Japanese social and ethical norms, which rarely encourage the withdrawal of intensive life support. Cultural and ethical backgrounds may need to be considered when assessing the effect of therapeutic interventions.

Blood Biomarkers and 6- to 7-Year Childhood Outcomes Following Neonatal Encephalopathy

OBJECTIVE

This study aimed to profile the cytokine/chemokine response from day 0 to 7 in infants (≥36 weeks of gestational age) with neonatal encephalopathy (NE) and to explore the association with long-term outcomes.

STUDY DESIGN

This was a secondary study of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network randomized controlled trial of whole body hypothermia for NE. Eligible infants with moderate-severe NE were randomized to cooling or normothermia. Blood spots were collected on days 0 to 1, 2 to 4, and 6 to 7. Twenty-four cytokines/chemokines were measured using a multiplex platform. Surviving infants underwent neurodevelopmental assessment at 6 to 7 years. Primary outcome was death or moderate-severe impairment defined by any of the following: intelligence quotient <70, moderate-severe cerebral palsy (CP), blindness, hearing impairment, or epilepsy.

RESULTS

Cytokine blood spots were collected from 109 participants. In total 99 of 109 (91%) were assessed at 6 to 7 years; 54 of 99 (55%) developed death/impairment. Neonates who died or were impaired had lower early regulated upon activation normal T cell expressed and secreted (RANTES) and higher day 7 monocyte chemotactic protein (MCP)-1 levels than neonates who survived without impairment. Though TNF-α levels had no association with death/impairment, higher day 0 to 1 levels were observed among neonates who died/developed CP. On multiple regression analysis adjusted for center, treatment group, sex, race, and level of hypoxic ischemic encephalopathy, higher RANTES was inversely associated with death/impairment (odds ratio (OR): 0.31, 95% confidence interval [CI]: 0.13-0.74), while day seven MCP-1 level was directly associated with death/impairment (OR: 3.70, 95% CI: 1.42-9.61). Targeted cytokine/chemokine levels demonstrated little variation with hypothermia treatment.

CONCLUSION

RANTES and MCP-1 levels in the first week of life may provide potential targets for future therapies among neonates with encephalopathy.

KEY POINTS

· Elevation of specific cytokines and chemokines in neonates with encephalopathy has been noted along with increased risk of neurodevelopmental impairment in infancy.. · Cytokine/chemokines at <7 days were assessed among neonates in a trial of hypothermia for HIE.. · Neonates who died or were impaired at 6 to 7 years following hypoxic-ischemic encephalopathy had lower RANTES and higher MCP-1 levels than those who survived without impairment..

Hypothermia is not therapeutic in a neonatal piglet model of inflammation-sensitized hypoxia-ischemia

BACKGROUND

Perinatal inflammation combined with hypoxia-ischemia (HI) exacerbates injury in the developing brain. Therapeutic hypothermia (HT) is standard care for neonatal encephalopathy; however, its benefit in inflammation-sensitized HI (IS-HI) is unknown.

METHODS

Twelve newborn piglets received a 2 µg/kg bolus and 1 µg/kg/h infusion over 52 h of Escherichia coli lipopolysaccharide (LPS). HI was induced 4 h after LPS bolus. After HI, piglets were randomized to HT (33.5 °C 1-25 h after HI, n = 6) or normothermia (NT, n = 6). Amplitude-integrated electroencephalogram (aEEG) was recorded and magnetic resonance spectroscopy (MRS) was acquired at 24 and 48 h. At 48 h, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive brain cell death, microglial activation/proliferation, astrogliosis, and cleaved caspase-3 (CC3) were quantified. Hematology and plasma cytokines were serially measured.

RESULTS

Two HT piglets died. aEEG recovery, thalamic and white matter MRS lactate/N-acetylaspartate, and TUNEL-positive cell death were similar between groups. HT increased microglial activation in the caudate, but had no other effect on glial activation/proliferation. HT reduced CC3 overall. HT suppressed platelet count and attenuated leukocytosis. Cytokine profile was unchanged by HT.

CONCLUSIONS

We did not observe protection with HT in this piglet IS-HI model based on aEEG, MRS, and immunohistochemistry. Immunosuppressive effects of HT and countering neuroinflammation by LPS may contribute to the observed lack of HT efficacy. Other immunomodulatory strategies may be more effective in IS-HI.

IMPACT

Acute infection/inflammation is known to exacerbate perinatal brain injury and can worsen the outcomes in neonatal encephalopathy. Therapeutic HT is the current standard of care for all infants with NE, but the benefit in infants with coinfection/inflammation is unknown. In a piglet model of inflammation (LPS)-sensitized HI, we observed no evidence of neuroprotection with cooling for 24 h, based on our primary outcome measures: aEEG, MRS Lac/NAA, and histological brain cell death. Additional neuroprotective agents, with beneficial immunomodulatory effects, require exploration in IS-HI models.

Efficacy of melatonin in term neonatal models of perinatal hypoxia-ischaemia

OBJECTIVE

Neonatal encephalopathy (NE) is an important cause of mortality and disability worldwide. Therapeutic hypothermia (HT) is an effective therapy, however not all babies benefit. Novel agents are urgently needed to improve outcomes. Melatonin in preclinical studies has promising neuroprotective properties. This meta-analysis assessed the efficacy of melatonin in term animal models of NE on cerebral infarct size, neurobehavioural tests and cell death.

METHODS

A literature search was carried out using Embase, MEDLINE and Web of Science (31 May 2021). We identified 14 studies and performed a meta-analysis with a random effects model using standardised mean difference (SMD) as the effect size. The risk of bias was assessed using the Systematic Review Centre for Laboratory animal Experimentation tool and publication bias was assessed with funnel plots, and adjusted using trim and fill analysis. Subgroup and meta-regression analyses were performed to assess the effects of study design variables.

RESULTS

We observed significant reduction in brain infarct size (SMD -2.05, 95% CI [-2.93, -1.16]), improved neurobehavioural outcomes (SMD -0.86, 95% CI [-1.23, -0.53]) and reduction in cell death (SMD -0.60, 95% CI [-1.06, -0.14]) favouring treatment with melatonin. Neuroprotection was evident as a single therapy and combined with HT. Subgroup analysis showed greater efficacy with melatonin given before or immediately after injury and with ethanol excipients. The overall effect size remained robust even after adjustment for publication bias.

INTERPRETATION

These studies demonstrate a significant neuroprotective efficacy of melatonin in term neonatal models of hypoxia-ischaemia, and suggest melatonin is a strong candidate for translation to clinical trials in babies with moderate-severe NE.

Therapeutic hypothermia in neonatal hypoxic encephalopathy: A systematic review and meta-analysis

Background

Therapeutic hypothermia (TH) is regarded as the most efficacious therapy for neonatal hypoxic encephalopathy. However, limitations in previous systematic reviews and the publication of new data necessitate updating the evidence. We conducted this up-to-date systematic review to evaluate the effects of TH in neonatal encephalopathy on clinical outcomes.

Methods

In this systematic review and meta-analysis, we searched Medline, Cochrane Library, Embase, LIVIVO, Web of Science, Scopus, CINAHL, major trial registries, and grey literature (from inception to October 31, 2021), for randomized controlled trials (RCT) comparing TH vs normothermia in neonatal encephalopathy. We included RCTs enrolling neonates (gestation ≥35 weeks) with perinatal asphyxia and encephalopathy, who received either TH (temperature ≤34°C) initiated within 6 hours of birth for ≥48 hours, vs no cooling. We excluded non-RCTs, those with delayed cooling, or cooling to >34°C. Two authors independently appraised risk-of-bias and extracted data on mortality and neurologic disability at four time points: neonatal (from randomization to discharge/death), infancy (18-24 months), childhood (5-10 years), and long-term (>10 years). Other outcomes included seizures, EEG abnormalities, and MRI findings. Summary data from published RCTs were pooled through fixed-effect meta-analysis.

Results

We identified 36 863 citations and included 39 publications representing 29 RCTs with 2926 participants. Thirteen studies each had low, moderate, and high risk-of-bias. The pooled risk ratios (95% confidence interval, CI) were as follows: neonatal mortality: 0.87 (95% CI = 0.75, 1.00), n = 2434, I² = 38%; mortality at 18-24 months: 0.88 (95% CI = 0.78, 1.01), n = 2042, I² = 51%; mortality at 5-10 years: 0.81 (95% CI = 0.62, 1.04), n = 515, I² = 59%; disability at 18-24 months: 0.62 (95% CI = 0.52, 0.75), n = 1440, I² = 26%; disability at 5-10 years: 0.68 (95% CI = 0.52, 0.90), n = 442, I² = 3%; mortality or disability at 18-24 months: 0.78 (95% CI = 0.72, 0.86), n = 1914, I² = 54%; cerebral palsy at 18-24 months: 0.63 (95% CI = 0.50, 0.78), n = 1136, I² = 39%; and childhood cerebral palsy: 0.63 (95% CI = 0.46, 0.85), n = 449, I² = 0%. Some outcomes showed significant differences by study-setting; the risk ratio (95% CI) for mortality at 18-24 months was 0.79 (95% CI = 0.66,0.93), n = 1212, I² = 7% in high-income countries, 0.67 (95% CI = 0.41, 1.09), n = 276, I² = 0% in upper-middle-income countries, and 1.18 (95% CI = 0.94, 1.47), n = 554, I² = 75% in lower-middle-income countries. The corresponding pooled risk ratios for ‘mortality or disability at 18-24 months’ were 0.77 (95% CI = 0.69, 0.86), n = 1089, I² = 0%; 0.56 (95% CI = 0.41, 0.78), n = 276, I² = 30%; and 0.92 (95% CI = 0.77, 1.09), n = 549, I² = 86% respectively. Trials with low risk of bias showed risk ratio of 0.97 (95% CI = 0.80, 1.16, n = 1475, I² = 62%) for neonatal mortality, whereas trials with higher risk of bias showed 0.71 (95% CI = 0.55, 0.91), n = 959, I² = 0%. Likewise, risk ratio for mortality at 18-24 months was 0.96 (95% CI = 0.83, 1.13), n = 1336, I² = 58% among low risk-of-bias trials, but 0.72 (95% CI = 0.56, 0.92), n = 706, I² = 0%, among higher risk of bias trials.

Conclusions

Therapeutic hypothermia for neonatal encephalopathy reduces neurologic disability and cerebral palsy, but its effect on neonatal, infantile and childhood mortality is uncertain. The setting where it is implemented affects the outcomes. Low(er) quality trials overestimated the potential benefit of TH.