Therapeutic hypothermia for neonatal encephalopathy

Automated Neuroprognostication Via Machine Learning in Neonates with Hypoxic-Ischemic Encephalopathy

OBJECTIVES

Neonatal hypoxic-ischemic encephalopathy is a serious neurologic condition associated with death or neurodevelopmental impairments. Magnetic resonance imaging (MRI) is routinely used for neuroprognostication, but there is substantial subjectivity and uncertainty about neurodevelopmental outcome prediction. We sought to develop an objective and automated approach for the analysis of newborn brain MRI to improve the accuracy of prognostication.

METHODS

We created an anatomic MRI template from a sample of 286 infants treated with therapeutic hypothermia, and labeled the deep gray-matter structures. We extracted quantitative information, including shape-related information, and information represented by complex patterns (radiomic measures), from each of these structures in all infants. We then trained an elastic net model to use either only these measures, only the infants' demographic and laboratory data, or both, to predict neurodevelopmental outcomes, as measured by the Bayley Scales of Infant and Toddler Development at 18 months of age.

RESULTS

Among those infants for whom Bayley scores were available for cognitive, language, and motor outcomes, we found sets of MRI-based measures that could predict their Bayley scores with correlations that were greater than the correlations based on only the demographic and laboratory data, explained more of the variance in the observed scores, and generated a smaller error; predictions based on the combination of the demographic-laboratory and MRI-based measures were similar or marginally better.

INTERPRETATION

Our findings show that machine learning models using MRI-based measures can predict neurodevelopmental outcomes in neonates with hypoxic-ischemic encephalopathy across all neurodevelopmental domains and across the full spectrum of outcomes. ANN NEUROL 2025;97:791-802.

Current Trends in the Imaging Diagnosis of Neonatal Respiratory Distress Syndrome (NRDS): Chest X-ray Versus Lung Ultrasound

Neonatal respiratory distress syndrome (NRDS) is a major cause of morbidity and mortality in newborns, particularly in neonatal intensive care units (NICUs). Until recently, its diagnosis had been based on clinical signs, arterial blood gas analysis, and chest X-ray (CXR). However, the frequent use of CXR exposes newborns to ionizing radiation, which can have long-term negative effects, including an increased risk of cancer, especially among premature infants. Lung ultrasound (LUS) has been proposed as a promising alternative for diagnosing NRDS due to its many advantages: no exposure to radiation, the ability to be performed at the bedside, repeatability, and ease of use. This review compared the diagnostic accuracy of LUS with the reference standard, CXR, in evaluating NRDS in newborns admitted to the NICU. Studies have shown that LUS can identify specific signs of NRDS, such as bilateral "white lung," pleural line abnormalities, and lung consolidations. The method has high sensitivity and specificity for diagnosing this condition and offers several advantages over other diagnostic methods; it does not involve ionizing radiation, thereby eliminating the risk of radiation exposure; it is cost-effective, easy to use, and can be performed at the patient's bedside, making it a viable alternative to CXR for reducing ionizing radiation exposure. Additionally, LUS can be used to monitor the progression of respiratory diseases and guide clinical management, especially in determining the optimal timing for surfactant administration in newborns with respiratory distress syndrome (RDS). We conclude that LUS is an effective and non-invasive alternative method for diagnosing and managing NRDS, with the potential to improve the safety and quality of care in the NICU, where rapid and safe diagnostic tools are essential for managing the health of newborns.

Omega-3 fatty acid diglyceride emulsions as a novel injectable acute therapeutic in neonatal hypoxic-ischemic brain injury

Hypoxic-ischemic encephalopathy (HIE), resulting from a lack of blood flow and oxygen before or during newborn delivery, is a leading cause of cerebral palsy and neurological disability in children. Therapeutic hypothermia (TH), the current standard of care in HIE, is only beneficial in 1 of 7-8 cases. Therefore, there is a critical need for more efficient treatments. We have previously reported that omega-3 (n-3) fatty acids (FA) carried by triglyceride (TG) lipid emulsions provide neuroprotection after experimental hypoxic-ischemic (HI) injury in neonatal mice. Herein, we propose a novel acute therapeutic approach using an n-3 diglyceride (DG) lipid emulsions. Importantly, n-3 DG preparations had much smaller particle size compared to commercially available or lab-made n-3 TG emulsions. We showed that n-3 DG molecules have the advantage of incorporating at substantially higher levels than n-3 TG into an in vitro model of phospholipid membranes. We also observed that n-3 DG after parenteral administration in neonatal mice reaches the bloodstream more rapidly than n-3 TG. Using neonatal HI brain injury models in mice and rats, we found that n-3 DG emulsions provide superior neuroprotection than n-3 TG emulsions or TH in decreasing brain infarct size. Additionally, we found that n-3 DGs attenuate microgliosis and astrogliosis. Thus, n-3 DG emulsions are a superior, promising, and novel therapy for treating HIE.

Exposure to Maternal Diabetes during Pregnancy Is Associated with Aggravated Short-Term Neonatal and Neurological Outcomes following Perinatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

Infants of diabetic mothers (IDM) are at higher risk of perinatal morbidities and glycemic instability, but the impact of maternal diabetes on neonatal and neurological short-term outcomes of neonates with hypoxic-ischemic encephalopathy (HIE) remains poorly described. Our objective was to determine the impact of maternal diabetes on neonatal and neurological short-term outcomes following neonatal HIE.

STUDY DESIGN

This was a retrospective single-center study including 102 term neonates with HIE who received therapeutic hypothermia (TH) treatment between 2013 and 2020. Multiple regression analysis was used to assess the relationship between the presence of maternal diabetes and short-term outcomes.

RESULTS

Neonates with HIE and maternal diabetes exposure had a significantly lower gestational age at birth (38.6 vs. 39.7 weeks of gestation, p = 0.005) and a significantly higher mean birth weight (3,588 ± 752 vs. 3,214 ± 514 g, p = 0.012). IDM with HIE were ventilated for longer duration (8 vs. 4 days, p = 0.0047) and had a longer neonatal intensive care unit (NICU) stay (18 vs. 11 days, p = 0.0483) as well as took longer time to reach full oral feed (15 vs. 7 days, p = 0.0432) compared with neonates of nondiabetic mother. Maternal diabetes was also associated with an increased risk of death or abnormal neurological examination at discharge in neonates with HIE (odds ratio: 6.41 [1.54-26.32]).

CONCLUSION

In neonates with HIE, maternal diabetes is associated with an increased risk of death or short-term neonatal morbidities, such as longer duration of ventilation, prolonged neonatal stay, greater need for tube feeding, and being discharged with an abnormal neurological examination. Strategies to prevent, reduce, or better control maternal diabetes during pregnancy should be prioritized to minimize complications after perinatal asphyxia.

KEY POINTS

· Maternal DB is associated with unfavorable outcomes.. · IDM have longer ventilatory support and tube feeding.. · IDM have higher risk of abnormal neurological examination..

The Association of Therapeutic Hypothermia With Seizure Burden in Neonates With Hypoxic-Ischemic Encephalopathy

OBJECTIVES

To compare seizure burden between newborn infants treated with therapeutic hypothermia (TH) and those that were not and to compare the need for antiseizure medications (ASM) in a cohort of infants who were diagnosed with neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

This was a retrospective cohort study on infants born after 35 weeks' gestation, diagnosed with moderate to severe HIE, monitored with amplitude-integrated electroencephalography (aEEG) and eligible for TH. Infants born before the implementation of TH in 2008 were compared with infants born thereafter who received TH. Seizure burden was assessed from aEEG as total time in minutes of seizures activity per hour of recording. Other clinical and demographic data were retrieved from a prospective local database of infants with HIE.

RESULTS

Overall, 149 of 207 infants were included in the study: 112 exposed to TH and 37 not exposed. Cooled infants had a lower seizure burden overall (0.4 vs 2.3 min/h, P < 0.001) and were also less likely to be treated with ASM (74% vs 100%, P < 0.001). In multivariable regression models, not exposed to TH, having a depressed aEEG background, and having higher Apgar scores were associated with higher seizure burden (incidence rate ratio: 4.78 for noncooled infants, P < 0.001); also, not exposed to TH was associated with a higher likelihood of multidrug ASM (odds ratio: 4.83, P < 0.001).

CONCLUSIONS

TH in infants with moderate to severe HIE is associated with significant reduction of seizure burden and ASM therapy.

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.

Sex Differences in Microglia Activation in a Rodent Model of Preterm Hypoxic Ischemic Injury with Caffeine Treatment

Preterm infants are often treated with caffeine as a respiratory stimulant. However, follow-up data shows caffeine may also have neuroprotective potential. There are several theories as to how caffeine might protect the brain, but none have been proven. This study looked at caffeine effects on microglial activation in rodent brains post hypoxic ischemic (HI) injury. Rat pups underwent either sham or HI surgery on P6, followed by treatment with either caffeine or saline. Forty-eight hours post-injury, brains were collected and underwent paraffin embedding and sectioning followed by immunofluorescence staining. Ionized calcium binding adaptor molecule 1 (Iba-1) was used to label microglia, and 4',6-diamindino-2-phenylindole (DAPI) was used to label DNA. Cell size measurements of microglia were obtained to gauge microglia activation, and chromatin condensation (DAPI optical density) was used as an index of neuronal cell death. Results suggest that caffeine does offer protective effects, based on significantly increased levels of cell death in HI-saline animals not seen in caffeine-treated HI males and females. However, the mechanism of action may be different. Male HI animals showed marginally reduced microglial activation following caffeine treatment, whereas females did not. Results indicate that though caffeine may act protectively in both sexes by reducing cell death, the benefits may be mediated by different mechanisms.

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.

Neonatal hypoxic-ischemic encephalopathy diagnosis and treatment: a National Survey in China

Background

Neonatal hypoxic-ischemic encephalopathy (HIE) affects as many as 100,000 infants each year in China. Therapeutic hypothermia reduces HIE related mortality and long-term neurodevelopmental disabilities. National guidelines for HIE management were published a decade ago. This study aimed to investigate the current status of HIE diagnosis and treatment in China.

Method

This prospective cross-sectional national survey used a questionnaire evaluating practices related to HIE management. Descriptive statistics and Chi-square or Fisher’s exact test were used, and a p-value of < 0.05 was considered significant.

Results

The 273 hospitals that completed the survey were located in 31 of the 34 provincial districts in China. Eighty-eight percent of the hospitals were Level III hospitals, and 74% treated 10 or more HIE cases annually. Awareness rates of the national guidelines for HIE diagnosis, HIE treatment, and therapeutic hypothermia protocol were 85, 63, and 78%, respectively. Neurological manifestations and blood gas were used as HIE diagnostic criteria by 96% (263/273) and 68% (186/273) of the hospitals, respectively. Therapeutic hypothermia was used in 54% (147/273) of hospitals. The percentage of general hospitals that implemented therapeutic hypothermia (43%, 71/165) was significantly lower than that in maternity and infant hospitals (67%, 49/73) (χ² = 11.752, p = 0.001) and children’s hospitals (77%, 27/35) (χ² = 13.446, p < 0.001). Reasons for not providing therapeutic hypothermia included reduction of HIE cases in recent years (39%), high cost of cooling devices and treatment (31%), lack of training (26%), and safety concerns (4%). Among the hospitals that provided therapeutic hypothermia, 27% (39/147) were in full compliance with the recommended protocol. Eighty-one percent (222/273) of the hospitals treated HIE infants with putative neuroprotective agents alone or in combination with cooling. Ninety-one percent of the hospitals had long-term neurodevelopmental follow-up programs for infants with HIE.

Conclusions

There is significant heterogeneity in HIE diagnosis and treatment in China. Therapeutic hypothermia has not become a standard of care for neonatal HIE nationwide. Unproven agents are widely used for HIE treatment. Nationwide standardization of HIE management and dissemination of therapeutic hypothermia represent the opportunities to reduce mortality and improve long-term neurodevelopmental outcomes of children affected by HIE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02737-6.

Artemin Is Upregulated by TrkB Agonist and Protects the Immature Retina Against Hypoxic-Ischemic Injury by Suppressing Neuroinflammation and Astrogliosis

Hypoxic-ischemia (HI) is a major cause of acquired visual impairment in children from developed countries. Previous studies have shown that systemic administration of 7,8-dihydroxyavone (DHF), a selective tropomyosin receptor kinase B (TrkB) agonist, provides long-term neuroprotection against HI injury in an immature retina. However, the target genes and the mechanisms of the neuroprotective effects of TrkB signaling are not known. In the present study, we induced an HI retinal injury through unilateral common carotid artery ligation followed by 8% oxygen for 2 h in P7 rat pups. DHF was administered intraperitoneally 2 h before and 18 h after the HI injury. A polymerase chain reaction (PCR) array was used to identify the target genes upregulated after the DHF treatment, which was then confirmed with quantitative real-time reverse transcriptase PCR and a western blot. Effects of the downstream mediator of DHF were assessed using an intravitreal injection of neutralizing antibody 4 h after DHF administration (24 h after HI). Meanwhile, the target protein was injected into the vitreous 24 h after HI to validate its protective effect when exogenously supplemented. We found that systemic DHF treatment after HI significantly increased the expression of the artemin (ARTN) gene and protein at P8 and P10, respectively. The neuroprotective effects of DHF were inhibited after the ARTN protein blockade, with an increase in neuroinflammation and astrogliosis. ARTN treatment showed long-term protection against HI injury at both the histopathological and functional levels. The neuroprotective effects of ARTN were related to a decrease in microglial activation at P17 and attenuation of astrogliosis at P29. ARTN enhances phosphorylation of RET, ERK, and JNK, but not AKT or p38 in the immature retina. Altogether, these results suggest that the neuroprotective effect of a TrkB agonist is partially exerted through a mechanism that involves ARTN because the protective effect is ameliorated by ARTN sequestration. ARTN treatment after HI injury protects the immature retina by attenuating late neuroinflammation and astrogliosis in the immature retina relating to the ARTN/RET/JNK/ERK signaling pathway. ARTN may be a strategy by which to provide long-term protection in the immature retina against HI injury.

Early neuroimaging and ultrastructural correlates of injury outcome after neonatal hypoxic-ischaemia

Hypoxic ischaemia encephalopathy is the major cause of brain injury in new-borns. However, to date, useful biomarkers which may be used to early predict neurodevelopmental impairment for proper commencement of hypothermia therapy is still lacking. This study aimed to determine whether the early neuroimaging characteristics and ultrastructural correlates were associated with different injury progressions and brain damage severity outcomes after neonatal hypoxic ischaemia. Longitudinal 7 T MRI was performed within 6 h, 24 h and 7 days after hypoxic ischaemia in rat pups. The brain damage outcome at 7 days post-hypoxic ischaemia assessed using histopathology and MRI were classified as mild, moderate and severe. We found there was a spectrum of different brain damage severity outcomes after the same duration of hypoxic ischaemia. The severity of brain damage determined using MRI correlated well with that assessed by histopathology. Quantitative MRI characteristics denoting water diffusivity in the tissue showed significant differences in the apparent diffusion coefficient deficit volume and deficit ratios within 6 h, at 24 h and 7 days after hypoxic ischaemia among the 3 different outcome groups. The susceptible brain areas to hypoxic ischaemia were revealed by the temporal changes in regional apparent diffusion coefficient values among three outcome groups. Within 6 h post-hypoxic ischaemia, a larger apparent diffusion coefficient deficit volume and deficit ratios and lower apparent diffusion coefficient values were highly associated with adverse brain damage outcome. In the apparent diffusion coefficient deficit areas detected early after hypoxic ischaemia which were highly associated with severe damage outcome, transmission electron microscopy revealed fragmented nuclei; swollen rough endoplasmic reticulum and degenerating mitochondria in the cortex and prominent myelin loss and axon detraction in the white matter. Taken together, different apparent diffusion coefficient patterns obtained early after hypoxic ischaemia are highly associated with different injury progression leading to different brain damage severity outcomes, suggesting the apparent diffusion coefficient characteristics may be applicable to early identify the high-risk neonates for hypothermia therapy.

Type 2 Innate Lymphoid Cells Accumulate in the Brain After Hypoxia-Ischemia but Do Not Contribute to the Development of Preterm Brain Injury

Background

The immune system of human and mouse neonates is relatively immature. However, innate lymphoid cells (ILCs), commonly divided into the subsets ILC1, ILC2, and ILC3, are already present in the placenta and other fetal compartments and exhibit higher activity than what is seen in adulthood. Recent reports have suggested the potential role of ILCs, especially ILC2s, in spontaneous preterm labor, which is associated with brain damage and subsequent long-term neurodevelopmental deficits. Therefore, we hypothesized that ILCs, and especially ILC2s, play a role in preterm brain injury.

Methods

C57Bl/6J mice at postnatal day 6 were subjected to hypoxia-ischemia (HI) insult induced by left carotid artery ligation and subsequent exposure to 10% oxygen in nitrogen. The presence of ILCs and ILC2s in the brain was examined at different time points after HI. The contribution of ILC2s to HI-induced preterm brain damage was explored using a conditionally targeted ILC2-deficient mouse strain (Rorα ^fl/fl IL7r ^Cre ), and gray and white-matter injury were evaluated at 7 days post-HI. The inflammatory response in the injured brain was assessed using immunoassays and immunochemistry staining.

Results

Significant increases in ILCs and ILC2s were observed at 24 h, 3 days, and 7 days post-HI in the injured brain hemisphere compared with the uninjured hemisphere in wild-type mice. ILC2s in the brain were predominantly located in the meninges of the injured ipsilateral hemispheres after HI but not in the brain parenchyma. Overall, we did not observe changes in cytokine/chemokine levels in the brains of Rorα ^fl/fl IL7r ^Cre mice compared with wild type animals apart from IL-13. Gray and white-matter tissue loss in the brain was not affected after HI in Rorα ^fl/fl IL7r ^Cre mice. Correspondingly, we did not find any differences in reactive microglia and astrocyte numbers in the brain in Rorα ^fl/fl IL7r ^Cre mice compared with wild-type mice following HI insult.

Conclusion

After HI, ILCs and ILC2s accumulate in the injured brain hemisphere. However, ILC2s do not contribute to the development of brain damage in this mouse model of preterm brain injury.

Therapeutic interventions for fetal inflammatory response syndrome (FIRS)

Fetal inflammatory response syndrome (FIRS) is a condition defined by systemic inflammation in the fetus, a rapid increase of pro-inflammatory cytokines into the fetal circulation (including interleukin-1 and interleukin-6), as well as a cellular response (such as increased neutrophils, monocyte/macrophages, and T cells) and the presence of funisitis. FIRS can lead to death and multisystem organ damage in the fetus and newborn. Brain injuries and subsequent risk of cerebral palsy and cognitive impairments are the most threatening long-term complications. This paper reviews the definition of FIRS, summarizes its associated complications, briefly describes the available methods to study FIRS, and discusses in more detail the potential therapeutic candidates that have been so far studied to protect the fetus/newborn from FIRS and to alleviate its associated complications and sequelae.

Therapeutic hypothermia and N-PASS; results from implementation in a level 3 NICU

BACKGROUND

Neonates that have been subjected to perinatal asphyxia and fulfill criteria for therapeutic hypothermia are cooled to 33.5 °C for 72 h. There is no consensus regarding sedation and analgesic use during hypothermia, but there is evidence supporting the importance of pain relief and adequate sedation. There is a need for assessment of the neonates need for pain relief and sedation, and for adjustments of medication to ensure adequate treatment. There are many different scoring tools available. We found the N-PASS (Neonatal Pain, Agitation and Sedation Scale) scoring tool to be the most suitable for this patient group as it assesses both pain and sedation.

METHODS

We translated the scoring tool according to guidelines published by Wilder et al., and scored neonates treated with therapeutic hypothermia. Sedation and analgesia were adjusted according to scoring results. At the end of the study a questionnaire was filled out by the nurses in charge of this group of patients.

RESULTS

Both pain and sedation scores did not reach the desired levels until day 3. The nurses reported a high level of satisfaction (79.7% were extremely of very satisfied), and 96.7% of the nurses found the neonates to be better pain relieved after the initiation of the study.

CONCLUSION

The implementation of the N-PASS scoring tool in our unit has been successful, and has led to better pain relief and sedation than before the implementation.

Leveraging the interplay of nanotechnology and neuroscience: Designing new avenues for treating central nervous system disorders

Nanotechnology has the potential to open many novel diagnostic and treatment avenues for disorders of the central nervous system (CNS). In this review, we discuss recent developments in the applications of nanotechnology in CNS therapies, diagnosis and biology. Novel approaches for the diagnosis and treatment of neuroinflammation, brain dysfunction, psychiatric conditions, brain cancer, and nerve injury provide insights into the potential of nanomedicine. We also highlight nanotechnology-enabled neuroscience techniques such as electrophysiology and intracellular sampling to improve our understanding of the brain and its components. With nanotechnology integrally involved in the advancement of basic neuroscience and the development of novel treatments, combined diagnostic and therapeutic applications have begun to emerge. Nanotheranostics for the brain, able to achieve single-cell resolution, will hasten the rate in which we can diagnose, monitor, and treat diseases. Taken together, the recent advances highlighted in this review demonstrate the prospect for significant improvements to clinical diagnosis and treatment of a vast array of neurological diseases. However, it is apparent that a strong dialogue between the nanoscience and neuroscience communities will be critical for the development of successful nanotherapeutics that move to the clinic, benefit patients, and address unmet needs in CNS disorders.

Therapeutic hypothermia in children: Which indications remain in 2018?

Experimental studies on therapeutic hypothermia in acute brain injury reported positive outcomes and identified two potential benefits, namely, reduction in seizure incidence and in intracranial pressure. Translating this evidence to humans is challenging, especially for conditions in pediatric patients, such as cardiac arrest, traumatic brain injury, and status epilepticus, among others. This narrative review aimed to discuss the current indications and benefits of therapeutic hypothermia in acute brain injury in the pediatric population (i.e., beyond the neonatal period) by analyzing the neurologic outcome and mortality data obtained from previous studies.

PPARα-Mediated Positive-Feedback Loop Contributes to Cold Exposure Memory

Fluctuations in food availability and shifts in temperature are typical environmental changes experienced by animals. These environmental shifts sometimes portend more severe changes; e.g., chilly north winds precede the onset of winter. Such telltale signs may be indicators for animals to prepare for such a shift. Here we show that HEK293A cells, cultured under starvation conditions, can “memorize” a short exposure to cold temperature (15 °C), which was evidenced by their higher survival rate compared to cells continuously grown at 37 °C. We refer to this phenomenon as “cold adaptation”. The cold-exposed cells retained high ATP levels, and addition of etomoxir, a fatty acid oxidation inhibitor, abrogated the enhanced cell survival. In our standard protocol, cold adaptation required linoleic acid (LA) supplementation along with the activity of Δ-6-desaturase (D6D), a key enzyme in LA metabolism. Moreover, supplementation with the LA metabolite arachidonic acid (AA), which is a high-affinity agonist of peroxisome proliferator-activated receptor-alpha (PPARα), was able to underpin the cold adaptation, even in the presence of a D6D inhibitor. Cold exposure with added LA or AA prompted a surge in PPARα levels, followed by the induction of D6D expression; addition of a PPARα antagonist or a D6D inhibitor abrogated both their expression, and reduced cell survival to control levels. We also found that the brief cold exposure transiently prevents PPARα degradation by inhibiting the ubiquitin proteasome system, and starvation contributes to the enhancement of PPARα activity by inhibiting mTORC1. Our results reveal an innate adaptive positive-feedback mechanism with a PPARα-D6D-AA axis that is triggered by a brief cold exposure in cells. “Cold adaptation” could have evolved to increase strength and resilience against imminent extreme cold temperatures.

Delivery Room Management of Meconium-Stained Newborns and Respiratory Support

: media-1vid110.1542/5839992674001PEDS-VA_2018-1485Video Abstract BACKGROUND AND OBJECTIVES: Recently, the Neonatal Resuscitation Program (NRP) recommended against routine endotracheal suctioning of meconium-stained nonvigorous newborns but suggested resuscitation with positive pressure ventilation. Our purpose is to study the effects of this change in management.

METHODS

In this multicenter cohort study, we compare 130 nonvigorous newborns born during the retrospective 1-year period before the implementation of new NRP guidelines (October 1, 2015, to September 30, 2016) to 101 infants born during the 1-year prospective period after implementation (October 1, 2016, to September 30, 2017).

RESULTS

Endotracheal suctioning was performed predominantly in the retrospective group compared with the prospective group (70% vs 2%), indicating the change in practice. A significantly higher proportion of newborns were admitted to the NICU for respiratory issues in the prospective group compared with the retrospective group (40% vs 22%) with an odds ratio (OR) of 2.2 (95% confidence interval [CI]: 1.2-3.9). Similarly, a significantly higher proportion of infants needed oxygen therapy (37% vs 19%) with an OR of 2.5 (95% CI: 1.2-4.5), mechanical ventilation (19% vs 9%) with an OR of 2.6 (95% CI: 1.1-5.8), and surfactant therapy (10% vs 2%) with an OR of 5.8 (95% CI: 1.5-21.8). There were no differences in the incidence of other outcomes, including meconium aspiration syndrome.

CONCLUSIONS

The recent NRP guideline change was not associated with an increased incidence of meconium aspiration syndrome but was associated with an increased incidence of NICU admissions for respiratory issues. Also, the need for mechanical ventilation, oxygen, and surfactant therapy increased.

Xenon Combined With Hypothermia in Perinatal Hypoxic-Ischemic Encephalopathy: A Noble Gas, a Noble Mission

Perinatal hypoxia-ischemia is a major cause of neonatal morbidity. It generates primary neuronal damage of the neonatal brain and later secondary damage when reperfusion of the ischemic brain tissue causes a surge of oxygen free radicals and inflammation. This post-hypoxic-ischemic brain damage is a leading cause of motor and intellectual disabilities in survivors. Research worldwide has focused on mitigating this injury. Mild or moderate hypothermia is the standard treatment in many centers. However, its benefit is modest and the search for combinatorial effective neuroprotectants continues. This review focuses on xenon as one such agent. The use of mild to moderate hypothermia is reviewed first. Then promising results on the use of xenon to potentiate the effect of hypothermia in in vitro and in vivo animal experiments are discussed. In the first feasibility study on human neonates, researchers found a significant benefit of using 50% xenon for 18 hours in addition to 72 hours of hypothermia. Yet, this additional benefit of xenon was lacking in a larger cohort study, potentially because xenon was used beyond six hours of birth. The future of using xenon is promising, but further clinical studies are awaited to confirm the feasibility of its routine use and its optimal timing, concentration, and duration, for human neonatal hypoxia-ischemia.

Behavioral and neuroanatomical outcomes in a rat model of preterm hypoxic-ischemic brain Injury: Effects of caffeine and hypothermia

The current study investigated behavioral and post mortem neuroanatomical outcomes in Wistar rats with a neonatal hypoxic-ischemic (HI) brain injury induced on postnatal day 6 (P6; Rice-Vannucci HI method; Rice et al., 1981). This preparation models brain injury seen in premature infants (gestational age (GA) 32-35 weeks) based on shared neurodevelopmental markers at time of insult, coupled with similar neuropathologic sequelae (Rice et al., 1981; Workman et al., 2013). Clinically, HI insult during this window is associated with poor outcomes that include attention deficit hyperactivity disorder (ADHD), motor coordination deficits, spatial memory deficits, and language/learning disabilities. To assess therapies that might offer translational potential for improved outcomes, we used a P6 HI rat model to measure the behavioral and neuroanatomical effects of two prospective preterm neuroprotective treatments - hypothermia and caffeine. Hypothermia (aka "cooling") is an approved and moderately efficacious intervention therapy for fullterm infants with perinatal hypoxic-ischemic (HI) injury, but is not currently approved for preterm use. Caffeine is a respiratory stimulant used during removal of infants from ventilation but has shown surprising long-term benefits, leading to consideration as a therapy for HI of prematurity. Current findings support caffeine as a preterm neuroprotectant; treatment significantly improved some behavioral outcomes in a P6 HI rat model and partially rescued neuropathology. Hypothermia treatment (involving core temperature reduction by 4 °C for 5 h), conversely, was found to be largely ineffective and even deleterious for some measures in both HI and sham rats. These results have important implications for therapeutic intervention in at-risk preterm populations, and promote caution in the application of hypothermia protocols to at-risk premature infants without further research.

Partnering With a Medical Malpractice Insurer to Improve Patient Safety and Decrease Risk

Implementing evolving science into clinical practice remains challenging. Assimilating new scientific evidence into clinical protocols and best practice recommendations, in a timely manner, can be difficult. In this article, we examine the value of partnering with a captive medical malpractice insurance company and its Patient Safety Organization to use data and convening opportunities to build upon the principles of implementation science and foster efficient and widespread adoption of the most current evidence-based interventions. Analyses of medical malpractice and root-cause analysis data set the context for this partnership and acted as a catalyst for creating best practice guidelines for adopting therapeutic hypothermia in the treatment of neonatal encephalopathy. What follows is a powerful example of successfully leveraging the collective wisdom of healthcare providers across specialties and institutional lines to move patient safety forward while managing risk.

Uptake of dendrimer-drug by different cell types in the hippocampus after hypoxic-ischemic insult in neonatal mice: Effects of injury, microglial activation and hypothermia

Perinatal hypoxic-ischemic encephalopathy (HIE) can result in neurodevelopmental disability, including cerebral palsy. The only treatment, hypothermia, provides incomplete neuroprotection. Hydroxyl polyamidoamine (PAMAM) dendrimers are being explored for targeted delivery of therapy for HIE. Understanding the biodistribution of dendrimer-conjugated drugs into microglia, neurons and astrocytes after brain injury is essential for optimizing drug delivery. We conjugated N-acetyl-L-cysteine to Cy5-labeled PAMAM dendrimer (Cy5-D-NAC) and used a mouse model of perinatal HIE to study effects of timing of administration, hypothermia, brain injury, and microglial activation on uptake. Dendrimer conjugation delivered therapy most effectively to activated microglia but also targeted some astrocytes and injured neurons. Cy5-D-NAC uptake was correlated with brain injury in all cell types and with activated morphology in microglia. Uptake was not inhibited by hypothermia, except in CD68+ microglia. Thus, dendrimer-conjugated drug delivery can target microglia, astrocytes and neurons and can be used in combination with hypothermia for treatment of HIE.