School-age outcomes of children without cerebral palsy cooled for neonatal hypoxic-ischaemic encephalopathy in 2008-2010

Long-Term Outcomes Following Hypoxic Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is the most common cause of neonatal encephalopathy and results in significant morbidity and mortality. Long-term outcomes of the condition encompass impairments across all developmental domains. While therapeutic hypothermia (TH) has improved outcomes for term and late preterm infants with moderate to severe HIE, trials are ongoing to investigate the use of TH for infants with mild or preterm HIE. There is no evidence that adjuvant therapies in combination with TH improve long-term outcomes. Numerous trials of various adjuvant therapies are underway in the quest to further improve outcomes for infants with HIE.

Neocortical cholinergic pathology after neonatal brain injury is increased by Alzheimer's disease-related genes in mice

Hypoxic-ischemic encephalopathy (HIE) in neonates causes mortality and neurologic morbidity, including poor cognition with a complex neuropathology. Injury to the cholinergic basal forebrain and its rich innervation of cerebral cortex may also drive cognitive pathology. It is uncertain whether genes associated with adult cognition-related neurodegeneration worsen outcomes after neonatal HIE. We hypothesized that neocortical damage caused by neonatal HI in mice is ushered by persistent cholinergic innervation and interneuron (IN) pathology that correlates with cognitive outcome and is exacerbated by genes linked to Alzheimer's disease. We subjected non-transgenic (nTg) C57Bl6 mice and mice transgenically (Tg) expressing human mutant amyloid precursor protein (APP-Swedish variant) and mutant presenilin (PS1-ΔE9) to the Rice-Vannucci HI model on postnatal day 10 (P10). nTg and Tg mice with sham procedure were controls. Visual discrimination (VD) was tested for cognition. Cortical and hippocampal cholinergic axonal and IN pathology and Aβ plaques, identified by immunohistochemistry for choline acetyltransferase (ChAT) and 6E10 antibody respectively, were counted at P210. Simple ChAT+ axonal swellings were present in all sham and HI groups; Tg mice had more than their nTg counterparts, but HI did not affect the number of axonal swellings in APP/PS1 Tg mice. In contrast, complex ChAT+ neuritic clusters (NC) occurred only in Tg mice; HI increased that burden. The abundance of ChAT+ clusters in specific regions correlated with decreased VD. The frequency of attritional ChAT+ INs in the entorhinal cortex (EC) was increased in Tg shams relative to their nTg counterparts, but HI obviated this difference. Cholinergic IN pathology in EC correlated with NC number. The Aβ deposition in APP/PS1 Tg mice was not exacerbated by HI, nor did it correlate with other metrics. Adult APP/PS1 Tg mice have significant cortical cholinergic axon and EC ChAT+ IN pathologies; some pathology was exacerbated by neonatal HI and correlated with VD. Mechanisms of neonatal HI induced cognitive deficits and cortical neuropathology may be modulated by genetic risk, perhaps accounting for some of the variability in outcomes.

Ultrasonic vocalization emission is altered following neonatal hypoxic-ischemic brain injury in mice

Neonatal hypoxic-ischemic (HI) brain injury leads to cognitive impairments including social communication disabilities. Current treatments do not sufficiently target these impairments, therefore new tools are needed to examine social communication in models for neonatal brain injury. Ultrasonic vocalizations (USVs) during early life show potential as a measurement for social development and reflect landmark developmental stages in neonatal mice. However, changes in USV emission early after HI injury have not been found yet. Our current study examines USV patterns and classes in the first 3 days after HI injury. C57Bl/6 mice were subjected to HI on postnatal day (P)9 and USVs were recorded between P10 and P12. Audio files were analyzed using the VocalMat automated tool. HI-injured mice emitted less USVs, for shorter durations, and at a higher frequency compared to control (sham-operated) littermates. The HI-induced alterations in USVs were most distinct at P10 and in the frequency range of 50-75 kHz. At P10 HI-injured mouse pups also produced different ratios of USV class types compared to control littermates. Moreover, alterations in the duration and frequency were specific to certain USV classes in HI animals compared to controls. Injury in the striatum and hippocampus contributed most to alterations in USV communication after HI. Overall, neonatal HI injury leads to USV alterations in newborn mice which could be used as a tool to study early HI-related social communication deficits.

Prognostic value of quantitative EEG in early hours of life for neonatal encephalopathy and neurodevelopmental outcomes

BACKGROUND

The ability to determine severity of encephalopathy is crucial for early neuroprotective therapies and for predicting neurodevelopmental outcome. The objective of this study was to assess a novel brain state of newborn (BSN) trend to distinguish newborns with presence of hypoxic ischemic encephalopathy (HIE) within hours after birth and predict neurodevelopmental outcomes at 2 years of age.

METHOD

This is a prospective cohort study of newborns at 36 weeks' gestation or later with and without HIE at birth. The Total Sanart Score (TSS) was calculated based on a modified Sarnat exam within 6 h of life. BSN was calculated from electroencephalogram (EEG) measurements initiated after birth. The primary outcome at 2 year of age was a diagnosis of death or disability using the Bayley Scales of Infant Development III.

RESULTS

BSN differentiated between normal and abnormal neurodevelopmental outcomes throughout the entire recording period from 6 h of life. Additionally, infants with lower BSN values had higher odds of neurodevelopmental impairment and HIE. BSN distinguished between normal (n = 86) and HIE (n = 46) and showed a significant correlation with the concomitant TSS.

CONCLUSION

BSN is a sensitive real-time marker for monitoring dynamic progression of encephalopathy and predicting neurodevelopmental impairment.

IMPACT

This is a prospective cohort study to investigate the ability of brain state of newborn (BSN) trend to predict neurodevelopmental outcome within the first day of life and identify severity of encephalopathy. BSN predicts neurodevelopmental outcomes at 2 years of age and the severity of encephalopathy severity. It also correlates with the Total Sarnat Score from the modified Sarnat exam. BSN could serve as a promising bedside trend aiding in accurate assessment and identification of newborns who may benefit from additional neuroprotection therapies.

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.

Resting-state functional connectivity in children cooled for neonatal encephalopathy

Therapeutic hypothermia improves outcomes following neonatal hypoxic-ischaemic encephalopathy, reducing cases of death and severe disability such as cerebral palsy compared with normothermia management. However, when cooled children reach early school-age, they have cognitive and motor impairments which are associated with underlying alterations to brain structure and white matter connectivity. It is unknown whether these differences in structural connectivity are associated with differences in functional connectivity between cooled children and healthy controls. Resting-state functional MRI has been used to characterize static and dynamic functional connectivity in children, both with typical development and those with neurodevelopmental disorders. Previous studies of resting-state brain networks in children with hypoxic-ischaemic encephalopathy have focussed on the neonatal period. In this study, we used resting-state fMRI to investigate static and dynamic functional connectivity in children aged 6-8 years who were cooled for neonatal hypoxic-ischaemic without cerebral palsy [n = 22, median age (interquartile range) 7.08 (6.85-7.52) years] and healthy controls matched for age, sex and socioeconomic status [n = 20, median age (interquartile range) 6.75 (6.48-7.25) years]. Using group independent component analysis, we identified 31 intrinsic functional connectivity networks consistent with those previously reported in children and adults. We found no case-control differences in the spatial maps of these intrinsic connectivity networks. We constructed subject-specific static functional connectivity networks by measuring pairwise Pearson correlations between component time courses and found no case-control differences in functional connectivity after false discovery rate correction. To study the time-varying organization of resting-state networks, we used sliding window correlations and deep clustering to investigate dynamic functional connectivity characteristics. We found k = 4 repetitively occurring functional connectivity states, which exhibited no case-control differences in dwell time, fractional occupancy or state functional connectivity matrices. In this small cohort, the spatiotemporal characteristics of resting-state brain networks in cooled children without severe disability were too subtle to be differentiated from healthy controls at early school-age, despite underlying differences in brain structure and white matter connectivity, possibly reflecting a level of recovery of healthy resting-state brain function. To our knowledge, this is the first study to investigate resting-state functional connectivity in children with hypoxic-ischaemic encephalopathy beyond the neonatal period and the first to investigate dynamic functional connectivity in any children with hypoxic-ischaemic encephalopathy.

Risk factors for infection and outcomes in infants with neonatal encephalopathy: a cohort study

BACKGROUND

To determine the association between early infection risk factors and short-term outcomes in infants with neonatal encephalopathy following perinatal asphyxia (NE).

METHODS

A retrospective population-based cohort study utilizing the National Neonatal Research Database that included infants with NE admitted to neonatal units in England and Wales, Jan 2008-Feb 2018.

EXPOSURE

one or more of rupture of membranes >18 h, maternal group B streptococcus colonization, chorioamnionitis, maternal pyrexia or antepartum antibiotics.

PRIMARY OUTCOME

death or nasogastric feeds/nil by mouth (NG/NBM) at discharge.

SECONDARY OUTCOMES

organ dysfunction; length of stay; intraventricular hemorrhage; antiseizure medications use.

RESULTS

998 (13.7%) out of 7265 NE infants had exposure to early infection risk factors. Primary outcome (20.3% vs. 23.1%, OR 0.87 (95% CI 0.71-1.08), p = 0.22), death (12.8% vs. 14.0%, p = 0.32) and NG/NBM (17.4% vs. 19.9%. p = 0.07) did not differ between the exposed and unexposed group. Time to full sucking feeds (OR 0.81 (0.69-0.95)), duration (OR 0.82 (0.71-0.95)) and the number of antiseizure medications (OR 0.84 (0.72-0.98)) were lower in exposed than unexposed infants after adjusting for confounders. Therapeutic hypothermia did not alter the results.

CONCLUSIONS

Infants with NE exposed to risk factors for early-onset infection did not have worse short-term adverse outcomes.

IMPACT

Risk factors for early-onset neonatal infection, including rupture of membranes >18 h, maternal group B streptococcus colonization, chorioamnionitis, maternal pyrexia or antepartum antibiotics, were not associated with death or short-term morbidity after cooling for NE. Despite exposure to risk factors for early-onset neonatal infection, infants with NE reached oral feeds earlier and needed fewer anti-seizure medications for a shorter duration than infants with NE but without such risk factors. This study supports current provision of therapeutic hypothermia for infants with NE and any risk factors for early-onset neonatal infection.

Socioemotional and Psychological Outcomes of Hypoxic-Ischemic Encephalopathy: A Systematic Review

BACKGROUND AND OBJECTIVES

Therapeutic hypothermia has reduced the risk of death or major disability following perinatal hypoxic-ischemic encephalopathy (HIE); however, many children who experience perinatal HIE still go on to develop personal and behavioral challenges, which can be difficult for caregivers and a public health burden for society. Our objective with this review is to systematically identify and synthesize studies that evaluate associations between perinatal HIE and socioemotional or psychological outcomes.

METHODS

We screened all search-returned journal articles from Cochrane Library, Embase, Medline, PsycINFO, Scopus, and Web of Science from data inception through February 1, 2023. Keywords related to HIE (eg, neonatal encephalopathy, neonatal brain injury) and outcomes (eg, social*, emotion*, behav* problem, psycholog*, psychiatr*) were searched with a predefined search string. We included all observational human studies reporting socioemotional or psychological sequelae of term HIE. Study data were recorded on standardized sheets, and the Newcastle-Ottawa Scale was adapted to assess study quality.

RESULTS

We included 43 studies documenting 3244 HIE participants and 2132 comparison participants. We found statistically significant associations between HIE and social and emotional, behavioral, and psychological and psychiatric deficits throughout infancy, childhood, and adolescence (19 studies). The authors of the included studies also report nonsignificant findings (11 studies) and outcomes without statistical comparison (25 studies).

CONCLUSIONS

Perinatal HIE may be a risk factor for a range of socioemotional and psychological challenges in the short- and long-term. Routine screening, early intervention, and follow-up support may be particularly beneficial to this population.

Motor, cognitive and behavioural outcomes after neonatal hypoxic-ischaemic encephalopathy

INTRODUCTION

The current neurodevelopmental status of patients with neonatal hypoxic-ischaemic encephalopathy (HIE) in Spain is unknown. Recent European studies highlight a shift of severe pathology towards mild motor disorders and emotional problems. The aim of this study was to analyse neurodevelopmental outcomes in a cohort of neonates with HIE at age 3 years.

PATIENTS AND METHOD

Multicentre observational study of neonates born at 35 or more weeks of gestation with moderate to severe HIE in 2011-2013 in 12 hospitals in a large Spanish region (91 217 m2), with the recruitment extended through 2017 in the coordinating hospital. We analysed the findings of neonatal neuroimaging and neurodevelopmental test scores at 3 years (Bayley-III, Peabody Picture Vocabulary Test and Child Behavior Checklist). The sample included 79 controls with no history of perinatal asphyxia.

RESULTS

Sixty-three patients were recruited, of whom 5 (7.9%) were excluded due to other pathology and 14 (24%) died. Of the 44 survivors, 42 (95.5%) were evaluated. Of these 42, 10 (24%) had adverse outcomes (visual or hearing impairment, epilepsy, cerebral palsy or developmental delay). Other detected problems were minor neurological signs in 6 of the 42 (14%) and a higher incidence of emotional problems compared to controls: introversion (10.5% vs. 1.3%), anxiety (34.2% vs. 11.7%) and depression (28.9% vs. 7.8%) (P < .05). The severity of the lesions on neuroimaging was significantly higher in patients with motor impairment (P = .004) or who died or had an adverse outcome (P = .027).

CONCLUSION

In addition to classical sequelae, the followup of patients with neonatal HIE should include the diagnosis and treatment of minor motor disorders and social and emotional problems.

Hypothermia combined with extracellular vesicles from clonally expanded immortalized mesenchymal stromal cells improves neurodevelopmental impairment in neonatal hypoxic-ischemic brain injury

BACKGROUND

Neonatal encephalopathy following hypoxia-ischemia (HI) is a leading cause of childhood death and morbidity. Hypothermia (HT), the only available but obligatory therapy is limited due to a short therapeutic window and limited efficacy. An adjuvant therapy overcoming limitations of HT is still missing. Mesenchymal stromal cell (MSC)-derived extracellular vesicles (EVs) have shown promising therapeutic effects in various brain injury models. Challenges associated with MSCs' heterogeneity and senescence can be mitigated by the use of EVs from clonally expanded immortalized MSCs (ciMSCs). In the present study, we hypothesized that intranasal ciMSC-EV delivery overcomes limitations of HT.

METHODS

Nine-day-old C57BL/6 mice were exposed to HI by occlusion of the right common carotid artery followed by 1 h hypoxia (10% oxygen). HT was initiated immediately after insult for 4 h. Control animals were kept at physiological body core temperatures. ciMSC-EVs or vehicle were administered intranasally 1, 3 and 5 days post HI/HT. Neuronal cell loss, inflammatory and regenerative responses were assessed via immunohistochemistry, western blot and real-time PCR 7 days after insult. Long-term neurodevelopmental outcome was evaluated by analyses of cognitive function, activity and anxiety-related behavior 5 weeks after HI/HT.

RESULTS

In contrast to HT monotherapy, the additional intranasal therapy with ciMSC-EVs prevented HI-induced cognitive deficits, hyperactivity and alterations of anxiety-related behavior at adolescence. This was preceded by reduction of striatal neuronal loss, decreased endothelial, microglia and astrocyte activation; reduced expression of pro-inflammatory and increased expression of anti-inflammatory cytokines. Furthermore, the combination of HT with intranasal ciMSC-EV delivery promoted regenerative and neurodevelopmental processes, including endothelial proliferation, neurotrophic growth factor expression and oligodendrocyte maturation, which were not altered by HT monotherapy.

CONCLUSION

Intranasal delivery of ciMSC-EVs represents a novel adjunct therapy, overcoming limitations of acute HT thereby offering new possibilities for improving long-term outcomes in neonates with HI-induced brain injury.

Acquired Brain Injuries Across the Perinatal Spectrum: Pathophysiology and Emerging Therapies

The development of the central nervous system can be directly disrupted by a variety of acquired factors, including infectious, inflammatory, hypoxic-ischemic, and toxic insults. Influences external to the fetus also impact neurodevelopment, including placental health, maternal comorbidities, adverse experiences, environmental exposures, and social determinants of health. Acquired perinatal brain insults tend to affect the developing brain in a stage-specific manner that reflects the susceptible cell types, developmental processes, and risk factors present at the time of the insult. In this review, we discuss the pathophysiology, neurodevelopmental outcomes, and management of common acquired perinatal brain conditions. In the fetal brain, we divide insults based on trimester, and in the postnatal brain, we focus on common pathologies that have a presentation dependent on gestational age at birth: white matter injury and germinal matrix hemorrhage/intraventricular hemorrhage in preterm infants and hypoxic-ischemic encephalopathy in term infants. Although specific treatments for fetal and newborn brain disorders are currently limited, we emphasize therapies in preclinical or early clinical phases of the development pipeline. The growing number of novel cell type- and stage-specific emerging therapies suggests that in the near future we may have a dramatically improved ability to treat acquired perinatal brain disorders and to mitigate the associated neurodevelopmental consequences.

Long-term motor development after hypothermia-treated hypoxic-ischaemic encephalopathy

AIMS

To describe longitudinal motor development in children treated with therapeutic- hypothermia (TH) due to neonatal hypoxic-ischaemic encephalopathy (HIE) and to explore motor functioning in early adolescence.

MATERIAL AND METHODS

Children treated with TH due to HIE during 2007-2009, in Stockholm, participated in a prospective follow-up study. Motor development was assessed on four occasions, reported as percentiles and at mean ages. Alberta Infant Motor Scale was used at 0.35 years of age, Bayley Scales of Infant and Toddler Development-III at 2.1 years and Movement Assessment Battery for Children (MABC-2) at 7.3 and 11.1 years of age. MABC-2 Checklist was completed by parents at 7.3 and 11.1 years of age. General cognition was assessed using Wechsler Intelligence Scales for Children Fifth Edition (WISC-V).

RESULTS

Thirty-one percent (14/45) of the children had a motor score ≤ 15th percentile, indicating risk of motor difficulties at 11.1 years of age, and simultaneously the scores from parents of 52% (23/44), indicating risk of motor difficulties in the everyday context. These children had significantly lower motor percentile at 2.1 years of age, but within the normal range. Longitudinal motor development displayed a weak association with WISC-V Full Scale IQ (rs0.38, p = 0.013).

CONCLUSION

Among survivors of hypothermia-treated HIE free of moderate/severe cerebral palsy, a third had MABC-2 scores indicating risk of motor difficulties at 11.1 years of age. As motor difficulties became more apparent over time, we suggest that children treated with TH due to neonatal HIE should be followed into at least middle school age.

Hypothermic Protection in Neocortex Is Topographic and Laminar, Seizure Unmitigating, and Partially Rescues Neurons Depleted of RNA Splicing Protein Rbfox3/NeuN in Neonatal Hypoxic-Ischemic Male Piglets

The effects of hypothermia on neonatal encephalopathy may vary topographically and cytopathologically in the neocortex with manifestations potentially influenced by seizures that alter the severity, distribution, and type of neuropathology. We developed a neonatal piglet survival model of hypoxic-ischemic (HI) encephalopathy and hypothermia (HT) with continuous electroencephalography (cEEG) for seizures. Neonatal male piglets received HI-normothermia (NT), HI-HT, sham-NT, or sham-HT treatments. Randomized unmedicated sham and HI piglets underwent cEEG during recovery. Survival was 2-7 days. Normal and pathological neurons were counted in different neocortical areas, identified by cytoarchitecture and connectomics, using hematoxylin and eosin staining and immunohistochemistry for RNA-binding FOX-1 homolog 3 (Rbfox3/NeuN). Seizure burden was determined. HI-NT piglets had a reduced normal/total neuron ratio and increased ischemic-necrotic/total neuron ratio relative to sham-NT and sham-HT piglets with differing severities in the anterior and posterior motor, somatosensory, and frontal cortices. Neocortical neuropathology was attenuated by HT. HT protection was prominent in layer III of the inferior parietal cortex. Rbfox3 immunoreactivity distinguished cortical neurons as: Rbfox3-positive/normal, Rbfox3-positive/ischemic-necrotic, and Rbfox3-depleted. HI piglets had an increased Rbfox3-depleted/total neuron ratio in layers II and III compared to sham-NT piglets. Neuronal Rbfox3 depletion was partly rescued by HT. Seizure burdens in HI-NT and HI-HT piglets were similar. We conclude that the neonatal HI piglet neocortex has: (1) suprasylvian vulnerability to HI and seizures; (2) a limited neuronal cytopathological repertoire in functionally different regions that engages protective mechanisms with HT; (3) higher seizure burden, insensitive to HT, that is correlated with more panlaminar ischemic-necrotic neurons in the somatosensory cortex; and (4) pathological RNA splicing protein nuclear depletion that is sensitive to HT. This work demonstrates that HT protection of the neocortex in neonatal HI is topographic and laminar, seizure unmitigating, and restores neuronal depletion of RNA splicing factor.

Cerebellar growth, volume and diffusivity in children cooled for neonatal encephalopathy without cerebral palsy

Children cooled for HIE and who did not develop cerebral palsy (CP) still underperform at early school age in motor and cognitive domains and have altered supra-tentorial brain volumes and white matter connectivity. We obtained T1-weighted and diffusion-weighted MRI, motor (MABC-2) and cognitive (WISC-IV) scores from children aged 6-8 years who were cooled for HIE secondary to perinatal asphyxia without CP (cases), and controls matched for age, sex, and socioeconomic status. In 35 case children, we measured cerebellar growth from infancy (age 4-15 days after birth) to childhood. In childhood, cerebellar volumes were measured in 26 cases and 23 controls. Diffusion properties (mean diffusivity, MD and fractional anisotropy, FA) were calculated in 24 cases and 19 controls, in 9 cerebellar regions. Cases with FSIQ ≤ 85 had reduced growth of cerebellar width compared to those with FSIQ > 85 (p = 0.0005). Regional cerebellar volumes were smaller in cases compared to controls (p < 0.05); these differences were not significant when normalised to total brain volume. There were no case-control differences in MD or FA. Interposed nucleus volume was more strongly associated with IQ in cases than in controls (p = 0.0196). Other associations with developmental outcome did not differ between cases and controls.

School-age outcomes of children after perinatal brain injury: a systematic review and meta-analysis

BACKGROUND

Over 3000 children suffer a perinatal brain injury in England every year according to national surveillance. The childhood outcomes of infants with perinatal brain injury are however unknown.

METHODS

A systematic review and meta-analyses were undertaken of studies published between 2000 and September 2021 exploring school-aged neurodevelopmental outcomes of children after perinatal brain injury compared with those without perinatal brain injury. The primary outcome was neurodevelopmental impairment, which included cognitive, motor, speech and language, behavioural, hearing or visual impairment after 5 years of age.

RESULTS

This review included 42 studies. Preterm infants with intraventricular haemorrhage (IVH) grades 3-4 were found to have a threefold greater risk of moderate-to-severe neurodevelopmental impairment at school age OR 3.69 (95% CI 1.7 to 7.98) compared with preterm infants without IVH. Infants with perinatal stroke had an increased incidence of hemiplegia 61% (95% CI 39.2% to 82.9%) and an increased risk of cognitive impairment (difference in full scale IQ -24.2 (95% CI -30.73 to -17.67) . Perinatal stroke was also associated with poorer academic performance; and lower mean receptive -20.88 (95% CI -36.66 to -5.11) and expressive language scores -20.25 (95% CI -34.36 to -6.13) on the Clinical Evaluation of Language Fundamentals (CELF) assessment. Studies reported an increased risk of persisting neurodevelopmental impairment at school age after neonatal meningitis. Cognitive impairment and special educational needs were highlighted after moderate-to-severe hypoxic-ischaemic encephalopathy. However, there were limited comparative studies providing school-aged outcome data across neurodevelopmental domains and few provided adjusted data. Findings were further limited by the heterogeneity of studies.

CONCLUSIONS

Longitudinal population studies exploring childhood outcomes after perinatal brain injury are urgently needed to better enable clinicians to prepare affected families, and to facilitate targeted developmental support to help affected children reach their full potential.

Mammillary body abnormalities and cognitive outcomes in children cooled for neonatal encephalopathy

AIM

To evaluate mammillary body abnormalities in school-age children without cerebral palsy treated with therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy (cases) and matched controls, and associations with cognitive outcome, hippocampal volume, and diffusivity in the mammillothalamic tract (MTT) and fornix.

METHOD

Mammillary body abnormalities were scored from T1-weighted magnetic resonance imaging (MRI) in 32 cases and 35 controls (median age [interquartile range] 7 years [6 years 7 months-7 years 7 months] and 7 years 4 months [6 years 7 months-7 years 7 months] respectively). Cognition was assessed using the Wechsler Intelligence Scale for Children, Fourth Edition. Hippocampal volume (normalized by total brain volume) was measured from T1-weighted MRI. Radial diffusivity and fractional anisotropy were measured in the MTT and fornix, from diffusion-weighted MRI using deterministic tractography.

RESULTS

More cases than controls had mammillary body abnormalities (34% vs 0%; p < 0.001). Cases with abnormal mammillary bodies had lower processing speed (p = 0.016) and full-scale IQ (p = 0.028) than cases without abnormal mammillary bodies, and lower scores than controls in all cognitive domains (p < 0.05). Cases with abnormal mammillary bodies had smaller hippocampi (left p = 0.016; right p = 0.004) and increased radial diffusivity in the right MTT (p = 0.004) compared with cases without mammillary body abnormalities.

INTERPRETATION

Cooled children with mammillary body abnormalities at school-age have reduced cognitive scores, smaller hippocampi, and altered MTT microstructure compared with those without mammillary body abnormalities, and matched controls.

WHAT THIS PAPER ADDS

Cooled children are at higher risk of mammillary body abnormalities than controls. Abnormal mammillary bodies are associated with reduced cognitive scores and smaller hippocampi. Abnormal mammillary bodies are associated with altered mammillothalamic tract diffusivity.

Automatic veins analysis of susceptibility weighted image in hypoxic-ischaemic encephalopathy

BACKGROUND AND OBJECTIVE

The purpose of this study is to evaluate venous vascular structure and distribution as prognostic indicators of developmental outcomes for infants with neonatal hypoxic-ischaemic encephalopathy (HIE) by detecting and analysing ridges representing vessels on susceptibility-weighted magnetic resonance images (SWIs).

METHODS

Forty-two infants with neonatal HIE underwent SWI in the neonatal period and neurodevelopmental assessment at age 2 years. Normalised histograms of the width, intensity, length and Hessian eigenvalues extracted from the ridge analysis of each patient's SWI are applied as feature vectors to feed into supervised classifiers such as the kNN and random forest (RF) classifiers to predict their neurodevelopmental outcomes. Here we also propose a supervised classifier for automatic prognosis of automated detection of SWI signs of HIE. Our classifier proposed in this paper demonstrates a superior performance in HIE prognosis for the datasets associated with cognitive and motor outcomes and it also enables to determination of brain regions which have been affected by hypoxia-ischaemia by extracting appropriate features from SWI images.

RESULTS

The feature vectors containing width, intensity, length, and eigenvalue show a promising classification accuracy of 78.67% ± 2.58Linear regression, polynomial regression, and support vector regression (SVR) models predicted outcomes and the lower mean relative errors (MRE) for motor and cognitive outcomes are 0.088 ± 0.073 and 0.101 ± 0.11 respectively.

CONCLUSION

The features derived from the vascular ridges improve the prognostic value of SWI in HIE. Our findings suggest that it is possible to predict neurological, motor, and cognitive outcomes by numerical analysis of neonatal SW images and to identify brain regions on SWI affected by hypoxia-ischaemia.

Long-term consequences of neonatal encephalopathy in the hypothermia era: protocol for a follow-up cohort study at 9 years of age

INTRODUCTION

Therapeutic hypothermia (TH) became the standard of care treatment for neonates with moderate and severe neonatal encephalopathy (NE) in most industrialized countries about 10 years ago. Although TH is effective in reducing mortality and the incidence of severe developmental disabilities, the recent literature converges in reporting frequent cognitive and behavioural difficulties at school entry in children with NE-TH. Although these challenges are deemed minor compared with cerebral palsy and intellectual disability, their impacts on a child's self-determination and family's well-being are quite significant. Therefore, the nature and extent of these difficulties need to be comprehensively described so that appropriate care can be offered.

METHODS AND ANALYSIS

The current study will be the largest follow-up study of neonates with NE treated with TH to characterize their developmental outcomes and associated brain structural profiles at 9 years of age. Specifically, we will compare executive function, attention, social cognition, behaviour, anxiety, self-esteem, peer problems, brain volume, cortical features, white matter microstructure and myelination between children with NE-TH and matched peers without NE. Associations of perinatal risk factors and structural brain integrity with cognitive, behavioural and psycho-emotional deficits will be evaluated to inform about the potential aggravating and protective factors associated with function.

ETHICS AND DISSEMINATION

This study is supported by the Canadian Institute of Health Research (202203PJT-480065-CHI-CFAC-168509), and received approval from the Pediatric Ethical Review Board of the McGill University Health Center (MP-37-2023-9320). The study findings will be disseminated in scientific journals and conferences and presented to parental associations and healthcare providers to inform best practices.

TRIAL REGISTRATION NUMBER

NCT05756296.

Harnessing the therapeutic potential of the stem cell secretome in neonatal diseases

Preterm birth and intrapartum related complications account for a substantial amount of mortality and morbidity in the neonatal period despite significant advancements in neonatal-perinatal care. Currently, there is a noticeable lack of curative or preventative therapies available for any of the most common complications of prematurity including bronchopulmonary dysplasia, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia and retinopathy of prematurity or hypoxic-ischemic encephalopathy, the main cause of perinatal brain injury in term infants. Mesenchymal stem/stromal cell-derived therapy has been an active area of investigation for the past decade and has demonstrated encouraging results in multiple experimental models of neonatal disease. It is now widely acknowledged that mesenchymal stem/stromal cells exert their therapeutic effects via their secretome, with the principal vector identified as extracellular vesicles. This review will focus on summarizing the current literature and investigations on mesenchymal stem/stromal cell-derived extracellular vesicles as a treatment for neonatal diseases and examine the considerations to their application in the clinical setting.

Factors associated with MRI success in children cooled for neonatal encephalopathy and controls

OBJECTIVE

To investigate if an association exists between motion artefacts on brain MRI and comprehension, co-ordination, or hyperactivity scores in children aged 6-8 years, cooled for neonatal encephalopathy (cases) and controls.

METHODS

Case children (n = 50) without cerebral palsy were matched with 43 controls for age, sex, and socioeconomic status. Children underwent T1-weighted (T1w), diffusion-weighted image (DWI) brain MRI and cognitive, behavioural, and motor skills assessment. Stepwise multivariable logistic regression assessed associations between unsuccessful MRI and comprehension (including Weschler Intelligence Scale for Children (WISC-IV) verbal comprehension, working memory, processing speed and full-scale IQ), co-ordination (including Movement Assessment Battery for Children (MABC-2) balance, manual dexterity, aiming and catching, and total scores) and hyperactivity (including Strengths and Difficulties Questionnaire (SDQ) hyperactivity and total difficulties scores).

RESULTS

Cases had lower odds of completing both T1w and DWIs (OR: 0.31, 95% CI 0.11-0.89). After adjusting for case-status and sex, lower MABC-2 balance score predicted unsuccessful T1w MRI (OR: 0.81, 95% CI 0.67-0.97, p = 0.022). Processing speed was negatively correlated with relative motion on DWI (r = -0.25, p = 0.026) and SDQ total difficulties score was lower for children with successful MRIs (p = 0.049).

CONCLUSIONS

Motion artefacts on brain MRI in early school-age children are related to the developmental profile.

IMPACT

Children who had moderate/severe neonatal encephalopathy are less likely to have successful MRI scans than matched controls. Motion artefact on MRI is associated with lower MABC-2 balance scores in both children who received therapeutic hypothermia for neonatal encephalopathy and matched controls, after controlling for case-status and sex. Exclusion of children with motion artefacts on brain MRI can introduce sampling bias, which impacts the utility of neuroimaging to understand the brain-behaviour relationship in children with functional impairments.

Hypoxic-Ischemic Encephalopathy: Changing Outcomes Across the Spectrum

Neonatal hypoxic-ischemic encephalopathy (HIE) is a leading cause of death and neurodevelopmental impairment in neonates. Therapeutic hypothermia (TH) is the only established effective therapy and randomized trials affirm that TH reduces death and disability in moderate-to-severe HIE. Traditionally, infants with mild HIE were excluded from these trials due to the perceived low risk for impairment. Recently, multiple studies suggest that infants with untreated mild HIE may be at significant risk of abnormal neurodevelopmental outcomes. This review will focus on the changing landscape of TH, the spectrum of HIE presentations and their neurodevelopmental outcomes.

Brain volumes and functional outcomes in children without cerebral palsy after therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy

AIM

To investigate whether brain volumes were reduced in children aged 6 to 8 years without cerebral palsy, who underwent therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy (patients), and matched controls, and to examine the relation between subcortical volumes and functional outcome.

METHOD

We measured regional brain volumes in 31 patients and 32 controls (median age 7 years and 7 years 2 months respectively) from T1-weighted magnetic resonance imaging (MRI). We assessed cognition using the Wechsler Intelligence Scales for Children, Fourth Edition and motor ability using the Movement Assessment Battery for Children, Second Edition (MABC-2).

RESULTS

Patients had lower volume of whole-brain grey matter, white matter, pallidi, hippocampi, and thalami than controls (false discovery rate-corrected p < 0.05). Differences in subcortical grey-matter volumes were not independent of total brain volume (TBV). In patients, hippocampal and thalamic volumes correlated with full-scale IQ (hippocampi, r = 0.477, p = 0.010; thalami, r = 0.452, p = 0.016) and MABC-2 total score (hippocampi, r = 0.526, p = 0.004; thalami, r = 0.505, p = 0.006) independent of age, sex, and TBV. No significant correlations were found in controls. In patients, cortical injury on neonatal MRI was associated with reduced volumes of hippocampi (p = 0.001), thalami (p = 0.002), grey matter (p = 0.015), and white matter (p = 0.013).

INTERPRETATION

Children who underwent therapeutic hypothermia have reduced whole-brain grey and white-matter volumes, with associations between hippocampal and thalamic volumes and functional outcomes.

Outcome at early school age and adolescence after hypothermia-treated hypoxic-ischaemic encephalopathy: an observational, population-based study

OBJECTIVE

We aimed to describe long-term outcomes following hypoxic-ischaemic encephalopathy (HIE) treated with therapeutic hypothermia (TH).

DESIGN

Prospective, population-based observational study.

SETTING

Tertiary level neonatal intensive care units and neonatal outpatient clinic, Karolinska University Hospital, Stockholm, Sweden.

PATIENTS

Sixty-six infants treated with TH due to HIE between 2007 and 2009.

INTERVENTIONS

At 6-8 years and 10-12 years of age, children were assessed using a standardised neurological examination, the Movement Assessment Battery for Children, Second Edition (MABC-2) and the Wechsler Intelligence Scales for Children IV/V. Parents completed the Five-to-Fifteen (FTF) questionnaire.

MAIN OUTCOME MEASURES

Adverse outcome among survivors was defined as cerebral palsy (CP), epilepsy, hearing or visual impairment, full-scale IQ (FSIQ) below 85, attention deficit disorder with/without hyperactivity, autism spectrum disorder or developmental coordination disorder.

RESULTS

Mortality was 12%. Seventeen per cent of survivors developed CP. Mean FSIQ was normal in children without major neuromotor impairment. Assessment in early adolescence revealed emerging deficits in 26% of children with a previously favourable outcome. The proportion of children exhibiting executive difficulties increased from 7% to 19%. This was reflected also by a significantly increased proportion of children with an FTF score >90th percentile compared with norms in early adolescence. The proportion of children with an MABC-2 score ≤5th percentile was also significantly increased compared with norms.

CONCLUSIONS

Survivors without major neuromotor impairment have normal intelligence. The incidence of executive difficulties appears to be increased in this patient population. More subtle difficulties may go undetected at early school-age.

Development of the corpus callosum and cognition after neonatal encephalopathy

OBJECTIVE

Neonatal imaging studies report corpus callosum abnormalities after neonatal hypoxic-ischaemic encephalopathy (HIE), but corpus callosum development and relation to cognition in childhood are unknown. Using magnetic resonance imaging (MRI), we examined the relationship between corpus callosum size, microstructure and cognitive and motor outcomes at early school-age children cooled for HIE (cases) without cerebral palsy compared to healthy, matched controls. A secondary aim was to examine the impact of HIE-related neonatal brain injury on corpus callosum size, microstructure and growth.

METHODS

Participants aged 6-8 years underwent MRI, the Movement Assessment Battery for Children Second Edition and Wechsler Intelligence Scale for Children Fourth Edition. Cross-sectional area, volume, fractional anisotropy and radial diffusivity of the corpus callosum and five subdivisions were measured. Multivariable regression was used to assess associations between total motor score, full-scale IQ (FSIQ) and imaging metrics.

RESULTS

Adjusting for age, sex and intracranial volume, cases (N = 40) compared to controls (N = 39) demonstrated reduced whole corpus callosum area (β = -26.9, 95% confidence interval [CI] = -53.17, -0.58), volume (β = -138.5, 95% CI = -267.54, -9.56), fractional anisotropy and increased radial diffusivity (P < 0.05) within segments II-V. In cases, segment V area (β = 0.18, 95% CI = 0.004, 0.35), volume (β = 0.04, 95% CI = 0.001, 0.079), whole corpus callosum fractional anisotropy (β = 13.8 95% CI = 0.6, 27.1) and radial diffusivity (β = -11.3, 95% CI = -22.22, -0.42) were associated with FSIQ. Growth of the corpus callosum was restricted in cases with a FSIQ ≤85, and volume was reduced in cases with mild neonatal multifocal injury compared to white matter injury alone.

INTERPRETATION

Following neonatal HIE, morphological and microstructural changes in the corpus callosum are associated with reduced cognitive function at early school age.

Communication skills in children aged 6-8 years, without cerebral palsy cooled for neonatal hypoxic-ischemic encephalopathy

We assessed communication skills of 48 children without cerebral palsy (CP) treated with therapeutic hypothermia (TH) for neonatal hypoxic-ischemic encephalopathy (HIE) (cases) compared to 42 controls at early school-age and examined their association with white matter diffusion properties in both groups and 18-month Bayley-III developmental assessments in cases. Parents completed a Children's Communication Checklist (CCC-2) yielding a General Communication Composite (GCC), structural and pragmatic language scores and autistic-type behavior score. GCC ≤ 54 and thresholds of structural and pragmatic language score differences defined language impairment. Using tract-based spatial statistics (TBSS), fractional anisotropy (FA) was compared between 31 cases and 35 controls. Compared to controls, cases had lower GCC (p = 0.02), structural (p = 0.03) and pragmatic language score (p = 0.04) and higher language impairments (p = 0.03). GCC correlated with FA in the mid-body of the corpus callosum, the cingulum and the superior longitudinal fasciculus (p < 0.05) in cases. Bayley-III Language Composite correlated with GCC (r = 0.34, p = 0.017), structural (r = 0.34, p = 0.02) and pragmatic (r = 0.32, p = 0.03) language scores and autistic-type behaviors (r = 0.36, p = 0.01).

Foetal amplitude-integrated electroencephalography: proof of principle of a novel foetal monitoring technique in adult volunteers

Peripartum hypoxic neonatal brain injury cannot be accurately predicted with current foetal monitoring techniques. Neonatal brain monitoring through amplitude-integrated electroencephalography (aEEG) is utilised when brain injury is suspected. Intrapartum aEEG assessment may improve detection of foetal hypoxia, facilitating earlier intervention. Using different engineered configurations in adult volunteers (n = 18), we monitored aEEG through application of two foetal scalp electrodes (FSEs). This aided development of a novel signal splitter, our Foetal heart rate and aEEG Monitoring System (FEMS) to monitor aEEG intrapartum. We then compared FEMS with gold-standard EEG monitoring simultaneously in two adults. Average percentage of interpretable aEEG signal was 61.3%, with the FEMS obtaining 72.15%. EEG signal on the aEEG device consistently showed a similar trace to gold standard EEG. This study demonstrates feasibility of aEEG monitoring in adults with FEMS utilising FSE inputs. An intrapartum foetal study utilising FEMS is due to commence shortly. IMPACT STATEMENTWhat is already known on this subject? Cardiotography, the current gold standard in foetal monitoring, is not associated with a reduction in cerebral palsy or infant mortality rates. Neonatal amplitude-integrated electroencephalography (aEEG) is an established method of monitoring brain function to guide commencing cooling therapy in suspected hypoxic brain injury. Intrapartum animal studies have illustrated foetal EEG changes reflecting evolving hypoxia.What do the results of this study add? This study demonstrates aEEG monitoring in human adult volunteers through application of foetal scalp electrodes and use of a novel signal splitter. This Foetal heart rate and aEEG Monitoring System (FEMS) provided a good overall percentage of aEEG signal, consistently showing a similar trace to gold standard EEG.What the implications are of these findings for clinical practice and/or further research? This proof of principle study provides the first step in developing a novel intrapartum foetal monitoring technique to monitor foetal aEEG in labour. This provides an exciting prospect of transferring well established neonatal monitoring techniques to facilitate accurate brain function assessment intrapartum and early intervention to reduce hypoxic brain injury. An intrapartum foetal study of this technology is due to begin in the near future.

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.

Imaging of Hypoxic-Ischemic Injury (in the Era of Cooling)

Hypoxic-ischemic injury (HII) is a major worldwide contributor of term neonatal mortality and long-term morbidity. At present, therapeutic hypothermia is the only therapy that has demonstrated efficacy in reducing severe disability or death in infants with moderate to severe encephalopathy. MRI and MRS performed during the first week of life are adequate to assess brain injury and offer prognosis. Patterns of injury will depend on the gestation age of the neonate, as well as the degree of hypotension.

Development of a composite diffusion tensor imaging score correlating with short-term neurological status in neonatal hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is the most common cause of neonatal acquired brain injury. Although conventional MRI may predict neurodevelopmental outcomes, accurate prognostication remains difficult. As diffusion tensor imaging (DTI) may provide an additional diagnostic and prognostic value over conventional MRI, we aimed to develop a composite DTI (cDTI) score to relate to short-term neurological function. Sixty prospective neonates treated with therapeutic hypothermia (TH) for HIE were evaluated with DTI, with a voxel size of 1 × 1 × 2 mm. Fractional anisotropy (FA) and mean diffusivity (MD) from 100 neuroanatomical regions (FA/MD *100 = 200 DTI parameters in total) were quantified using an atlas-based image parcellation technique. A least absolute shrinkage and selection operator (LASSO) regression was applied to the DTI parameters to generate the cDTI score. Time to full oral nutrition [short-term oral feeding (STO) score] was used as a measure of short-term neurological function and was correlated with extracted DTI features. Seventeen DTI parameters were selected with LASSO and built into the final unbiased regression model. The selected factors included FA or MD values of the limbic structures, the corticospinal tract, and the frontotemporal cortices. While the cDTI score strongly correlated with the STO score (rho = 0.83, p = 2.8 × 10-16), it only weakly correlated with the Sarnat score (rho = 0.27, p = 0.035) and moderately with the NICHD-NRN neuroimaging score (rho = 0.43, p = 6.6 × 10-04). In contrast to the cDTI score, the NICHD-NRN score only moderately correlated with the STO score (rho = 0.37, p = 0.0037). Using a mixed-model analysis, interleukin-10 at admission to the NICU (p = 1.5 × 10-13) and tau protein at the end of TH/rewarming (p = 0.036) and after rewarming (p = 0.0015) were significantly associated with higher cDTI scores, suggesting that high cDTI scores were related to the intensity of the early inflammatory response and the severity of neuronal impairment after TH. In conclusion, a data-driven unbiased approach was applied to identify anatomical structures associated with some aspects of neurological function of HIE neonates after cooling and to build a cDTI score, which was correlated with the severity of short-term neurological functions.

Biomarker und Neuromonitoring zur Entwicklungsprognose nach perinataler Hirnschädigung

Das sich entwickelnde Gehirn ist in der Perinatalperiode besonders empfindlich für eine Vielzahl von Insulten, wie z. B. Extremfrühgeburtlichkeit und perinatale Asphyxie. Ihre Komplikationen können zu lebenslangen neurokognitiven, sensorischen und psychosozialen Einschränkungen führen; deren Vorhersage bleibt eine Herausforderung. Eine Schlüsselfunktion kommt der möglichst exakten Identifikation von Hirnläsionen und funktionellen Störungen zu. Die Prädiktion stützt sich auf frühe diagnostische Verfahren und die klinische Erfassung der Meilensteine der Entwicklung. Zur klinischen Diagnostik und zum Neuromonitoring in der Neonatal- und frühen Säuglingsperiode stehen bildgebende Verfahren zur Verfügung. Hierzu zählen zerebrale Sonographie, MRT am errechneten Termin, amplitudenintegriertes (a)EEG und/oder klassisches EEG, Nah-Infrarot-Spektroskopie, General Movements Assessment und die frühe klinische Nachuntersuchung z. B. mithilfe der Hammersmith Neonatal/Infant Neurological Examination. Innovative Biomarker und -muster (Omics) sowie (epi)genetische Prädispositionen sind Gegenstand wissenschaftlicher Untersuchungen. Neben der Erfassung klinischer Risiken kommt psychosozialen Faktoren im Umfeld des Kindes eine entscheidende Rolle zu. Eine möglichst akkurate Prognose ist mit hohem Aufwand verbunden, jedoch zur gezielten Beratung der Familien und der Einleitung von frühen Interventionen, insbesondere vor dem Hintergrund der hohen Plastizität des sich entwickelnden Gehirns, von großer Bedeutung. Diese Übersichtsarbeit fokussiert die Charakterisierung der oben genannten Verfahren und ihrer Kombinationsmöglichkeiten. Zudem wird ein Ausblick gegeben, wie innovative Techniken in Zukunft die Prädiktion der Entwicklung und Nachsorge dieser Kinder vereinfachen können.

Moderate to severe neonatal encephalopathy with suspected hypoxic-ischaemic encephalopathy in cooled term infants born in Tygerberg Academic Hospital: Characteristics of fetal monitoring and modifiable factors

Background. In South Africa, in babies >2 500 g, intrapartum asphyxia is the main cause of neonatal death or stillbirth in those who were alive prior to labour. In a developing population, ~60% of neonatal encephalopathy (NE) has evidence of intrapartum hypoxic ischaemia. Therapeutic hypothermia for term babies born with NE can improve neonatal prognosis and long-term survival. Objectives. To identify the healthcare worker- and system-related modifiable factor(s) that were associated with NE in babies of ≥36 weeks’ gestation born at Tygerberg Hospital (a secondary/tertiary referral hospital) between 1 January 2016 and 30 December 2018. Methods. This was an observational cross-sectional study analysing data from the Tygerberg Hospital Hypoxic Ischaemic Encephalopathy database, the electronic labour ward register, the mortality database and clinical data from patient folders. Results. A total of 118 babies were admitted for head cooling, and therefore included in the study. The hospital in-born rate for serious encephalopathy is 5.5/1 000 in singleton live-born babies (9/1 000 rate for live-born deliveries ≥36 weeks). A sentinel event was identified in 19 (16%) cases. Delay in accessing theatre was the main system-related modifiable factor (25/58 or 43% of cases delivered by emergency caesarean delivery). The average decision-to-incision time was 1 hour 40 minutes, while the average bed occupancy in the emergency maternity centre was 102%. Failure to recognise or respond to an abnormal cardiotocograph was the dominant avoidable factor related to healthcare workers in 34 cases (36.4%). Conclusion. Babies born with severe NE place a burden on parents, healthcare staff and resources. Careful intrapartum care, including utilisation of protocols for the use of oxytocin, are imperative. It is recommended that improved access to emergency theatres and appropriately trained staff for maternity units should be a priority for healthcare planners.

Hammersmith Infant Neurological Examination in infants born at term: Predicting outcomes other than cerebral palsy

AIM

We explored the ability of the Hammersmith Infant Neurological Examination (HINE) to identify cognitive performance delay at 2 years in a large cohort of infants born at term.

METHOD

We conducted a retrospective study of infants born at term at risk of neurodevelopmental impairments assessed using the HINE between 3 and 12 months post-term age and compared them with a cohort of typically developing infants born at term. All infants performed a neurodevelopmental assessment at 2 years of age using the Mental Development Index (MDI) of the Bayley Scales of Infant Development, Second Edition; the presence of cerebral palsy (CP) was also reported. The infants were classified as being cognitively normal/mildly delayed or significantly delayed (MDI < 70). The predictive validity of HINE scores for significantly delayed cognitive performance, in infants with and without CP, was calculated using specific cut-off scores according to age at assessment.

RESULTS

A total of 446 at-risk and 235 typically developing infants (345 males, 336 females; mean [SD] gestational age 38.7 weeks [1.4], range 37-43 weeks) were included. Of the at-risk infants, 408 did not have CP at 2 years; 243 had a normal/mild delayed MDI and 165 had an MDI less than 70. Of the at-risk infants, 38 developed CP. HINE scores showed a good sensitivity and specificity, mainly after 3 months, for identifying significantly delayed cognitive performance in infants without CP. In those with CP, the score was associated with their cognitive performance. The comparison group had the highest HINE scores.

INTERPRETATION

The HINE provides evidence about the risk of delayed cognitive performance at age 2 years in infants born at term with and without CP.

Mammillary body injury in neonatal encephalopathy: a multicentre, retrospective study

BACKGROUND

The mammillary bodies (MBs) have repeatedly been shown to be critical for memory, yet little is known about their involvement in numerous neurological conditions linked to memory impairments, including neonatal encephalopathy.

METHODS

We implemented a multicentre retrospective study, assessing magnetic resonance scans of 219 infants with neonatal encephalopathy who had undergone hypothermia treatment in neonatal intensive care units located in the Netherlands and Italy.

RESULTS

Abnormal MB signal was observed in ~40% of infants scanned; in half of these cases, the brain appeared otherwise normal. MB involvement was not related to the severity of encephalopathy or the pattern/severity of hypoxic-ischaemic brain injury. Follow-up scans were available for 18 cases with abnormal MB signal; in eight of these cases, the MBs appeared severely atrophic.

CONCLUSIONS

This study highlights the importance of assessing the status of the MBs in neonatal encephalopathy; this may require changes to scanning protocols to ensure that the slices are sufficiently thin to capture the MBs. Furthermore, long-term follow-up of infants with abnormal MB signal is needed to determine the effects on cognition, which may enable the use of early intervention strategies. Further research is needed to assess the role of therapeutic hypothermia in MB involvement in neonatal encephalopathy.

IMPACT

The MBs are particularly sensitive to hypoxia in neonates. Current hypothermia treatment provides incomplete protection against MB injury. MB involvement is likely overlooked as it can often occur when the rest of the brain appears normal. Given the importance of the MBs for memory, it is necessary that this region is properly assessed in neonatal encephalopathy. This may require improvements in scanning protocols.

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.

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.

New Horizons in Mild Hypoxic-ischemic Encephalopathy: A Standardized Algorithm to Move past Conundrum of Care

Hypoxic-ischemic encephalopathy (HIE) presents clinically with a neonatal encephalopathy (NE) whereby the mild spectrum is difficult to classify immediately after birth. For decades trials have focused exclusively on infants with moderate-severe HIE s, as these infants were easier to identify after birth and had the highest risk of adverse outcomes. Twenty years after those trials, the PRIME study finally solved the first part of the conundrum by providing a definition of mild HIE in the first 6 hours. There is strong biological plausibility and preclinical evidence supporting the efficacy of therapeutic hypothermia (TH) but there is a lack of comparative clinical data to establish the risk-benefit in mild HIE. The fundamental question of how best to manage mild HIE remains unanswered. This review will summarize (1) the evidence that neonates with mild HIE are at significant risk for adverse outcomes, (2) the gaps/controversies in management, and (3) an algorithm of care is proposed to ensure standardized management of mild HIE and the direction of future trials.

Physiological responses to cuddling babies with hypoxic-ischaemic encephalopathy during therapeutic hypothermia: an observational study

OBJECTIVES

To determine whether parents cuddling infants during therapeutic hypothermia (TH) would affect cooling therapy, cardiorespiratory or neurophysiological measures. The secondary aim was to explore parent-infant bonding, maternal postnatal depression and breastfeeding.

DESIGN

Prospective observational study.

SETTING

Two tertiary neonatal intensive care units (NICU).

PARTICIPANTS

Parents and their term-born infants (n=27) receiving TH and intensive care for neonatal hypoxic-ischaemic encephalopathy.

INTERVENTIONS

Cuddling up to 2 hours during TH using a standard operating procedure developed in the study (CoolCuddle).

MAIN OUTCOME MEASURES

Mean difference in temperature, cardiorespiratory and neurophysiological variables before, during and after the cuddle. Secondary outcomes were parental bonding, maternal postnatal depression and breastfeeding.

RESULTS

During 70 CoolCuddles (115 cumulative hours), there were measurable increases in rectal temperature (0.07°C (0.03 to 0.10)) and upper margin of amplitude-integrated electroencephalogram (1.80 µV (0.83 to 2.72)) and decreases in oxygen saturations (-0.57% (-1.08 to -0.05)) compared with the precuddle period. After the cuddle, there was an increase in end-tidal CO₂ (0.25 kPa (95% CI 0.14 to 0.35)) and mean blood pressure (4.09 mm Hg (95% CI 0.96 to 7.21)) compared with the precuddle period. From discharge to 8 weeks postpartum, maternal postnatal depression declined (13 (56.5%) vs 5 (23.8%), p=0.007); breastfeeding rate differed (71% vs 50%, p=0.043), but was higher than national average at discharge (70% vs 54.6%) and mother-infant bonding (median (IQR): 3 (0-6) vs 3 (1-4)) remained stable.

CONCLUSION

In this small study, CoolCuddle was associated with clinically non-significant, but measurable, changes in temperature, cardiorespiration and neurophysiology. No infant met the criteria to stop the cuddles or had any predefined adverse events. CoolCuddle may improve breastfeeding and requires investigation in different NICU settings.

Motor function and white matter connectivity in children cooled for neonatal encephalopathy

Therapeutic hypothermia reduces the incidence of severe motor disability, such as cerebral palsy, following neonatal hypoxic-ischaemic encephalopathy. However, cooled children without cerebral palsy at school-age demonstrate motor deficits and altered white matter connectivity. In this study, we used diffusion-weighted imaging to investigate the relationship between white matter connectivity and motor performance, measured using the Movement Assessment Battery for Children-2, in children aged 6-8 years treated with therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy at birth, who did not develop cerebral palsy (cases), and matched typically developing controls. Correlations between total motor scores and diffusion properties in major white matter tracts were assessed in 33 cases and 36 controls. In cases, significant correlations (FDR-corrected P < 0.05) were found in the anterior thalamic radiation bilaterally (left: r = 0.513; right: r = 0.488), the cingulate gyrus part of the left cingulum (r = 0.588), the hippocampal part of the left cingulum (r = 0.541), and the inferior fronto-occipital fasciculus bilaterally (left: r = 0.445; right: r = 0.494). No significant correlations were found in controls. We then constructed structural connectivity networks, for 22 cases and 32 controls, in which nodes represent brain regions and edges were determined by probabilistic tractography and weighted by fractional anisotropy. Analysis of whole-brain network metrics revealed correlations (FDR-corrected P < 0.05), in cases, between total motor scores and average node strength (r = 0.571), local efficiency (r = 0.664), global efficiency (r = 0.677), clustering coefficient (r = 0.608), and characteristic path length (r = -0.652). No significant correlations were found in controls. We then investigated edge-level association with motor function using the network-based statistic. This revealed subnetworks which exhibited group differences in the association between motor outcome and edge weights, for total motor scores (P = 0.0109) as well as for balance (P = 0.0245) and manual dexterity (P = 0.0233) domain scores. All three of these subnetworks comprised numerous frontal lobe regions known to be associated with motor function, including the superior frontal gyrus and middle frontal gyrus. The subnetwork associated with total motor scores was highly left-lateralised. These findings demonstrate an association between impaired motor function and brain organisation in school-age children treated with therapeutic hypothermia for neonatal hypoxic-ischaemic encephalopathy.

Neonatal hypoxic-ischaemic encephalopathy: Motor impairment beyond cerebral palsy

BACKGROUND

Research investigating neuromotor function in the absence of cerebral palsy (CP) for children who had neonatal HIE is limited.

AIMS

To investigate school-age neurological and neuromotor function, and correlations with attention, neonatal Magnetic Resonance Imaging (MRI), and neuromotor assessments at toddler age.

METHODS

Twenty-seven children with neonatal HIE without CP who underwent hypothermia treatment and a comparison group of 20 children were assessed at age 5-7 years for Minor Neurological Dysfunction (MND; simplified Touwen), motor skills (Movement Assessment Battery for Children-2; MABC-2), parental concern over motor function (MABC Checklist), general cognition (Wechsler Preschool and Primary Scale of Intelligence-IV, WPPSI), and attention (DuPaul ADHD Rating Scale). Neurological examination and motor development, using Bayley-3 scales, at age 24-months was extracted from the clinical database. Clinical neonatal MRI was assessed for hypoxic-ischaemic injury.

RESULTS

In the HIE group, MND was more prevalent (p = 0.026) and M-ABC performance (total score p = 0.006; balance subtest p = 0.008) was worse; parents were more concerned about children's motor function (p = 0.011). HIE group inattention scores were higher (p = 0.032), which correlated with lower MABC-2 scores (rs = -0.590, p = 0.004). Neurological examination at 24-months correlated with MND (rs = 0.437, p = 0.033); Bayley-3 motor scores did not correlate with M-ABC-2 scores (rs = 368, p = 0.133). Neonatal MRI findings were not associated with school-age MND (rs = 0.140, p = 0.523) or MABC-2 (rs = 0.300, p = 0.165).

CONCLUSIONS

Children with neonatal HIE, without CP, treated with hypothermia may be more likely to develop MND and motor difficulties than typically developing peers. Inattention may contribute to motor performance. In the absence of CP, neonatal MRI and toddler age assessment of motor development have limited predictive value for school-age outcome. Since this was an exploratory study with a small sample size, findings should be confirmed by a definite larger study.

Proposing a care practice bundle for neonatal encephalopathy during therapeutic hypothermia

Neonates with neonatal encephalopathy (NE) often present with multi-organ dysfunction that requires multidisciplinary specialized management. Care of the neonate with NE is thus complex with interaction between the brain and various organ systems. Illness severity during the first days of birth, and not only during the initial hypoxia-ischemia event, is a significant predictor of adverse outcomes in neonates with NE treated with therapeutic hypothermia (TH). We thus propose a care practice bundle dedicated to support the injured neonatal brain that is based on the current best evidence for each organ system. The impact of using such bundle on outcomes in NE remains to be demonstrated.

Neurological and developmental outcomes following neonatal encephalopathy treated with therapeutic hypothermia

In randomized trials, therapeutic hypothermia (TH) is associated with reduced prevalence of the composite outcome mortality or neurodevelopmental morbidity in infants with neonatal encephalopathy (NE). Following systematic review, the reduction in prevalence of both mortality and infant neuromorbidity is clear. Among three trials reporting school age outcomes, the effects of NE and TH suggest that such benefit persists into middle childhood, but none of the major trials were powered to detect differences in these outcomes. Cognitive, educational and behavioural outcomes are all adversely affected by NE in children without moderate or severe neuromorbidity. High-quality longitudinal studies of neurocognitive and educational outcomes following NE in the era of TH, including studies incorporating multimodal neuroimaging assessments, are required to characterise deficits more precisely so that robust interventional targets may be developed, and resource planning can occur. Understanding the impact of NE on families and important educational, social, and behavioural outcomes in childhood is critical to attempts to optimise outcomes through interventions.

Therapies for neonatal encephalopathy: Targeting the latent, secondary and tertiary phases of evolving brain injury

In term and near-term neonates with neonatal encephalopathy, therapeutic hypothermia protocols are well established. The current focus is on how to improve outcomes further and the challenge is to find safe and complementary therapies that confer additional protection, regeneration or repair in addition to cooling. Following hypoxia-ischemia, brain injury evolves over three main phases (latent, secondary and tertiary), each with a different brain energy, perfusion, neurochemical and inflammatory milieu. While therapeutic hypothermia has targeted the latent and secondary phase, we now need therapies that cover the continuum of brain injury that spans hours, days, weeks and months after the initial event. Most agents have several therapeutic actions but can be broadly classified under a predominant action (e.g., free radical scavenging, anti-apoptotic, anti-inflammatory, neuroregeneration, and vascular effects). Promising early/secondary phase therapies include Allopurinol, Azithromycin, Exendin-4, Magnesium, Melatonin, Noble gases and Sildenafil. Tertiary phase agents include Erythropoietin, Stem cells and others. We review a selection of promising therapeutic agents on the translational pipeline and suggest a framework for neuroprotection and neurorestoration that targets the evolving injury.

Children with neonatal Hypoxic Ischaemic Encephalopathy (HIE) treated with therapeutic hypothermia are not as school ready as their peers

AIM

We aimed to determine whether children with neonatal Hypoxic Ischaemic Encephalopathy (HIE) treated with therapeutic hypothermia (TH) differ from their peers on measures of fine motor skills, executive function, language and general cognitive abilities, factors that are important for school readiness.

METHODS

We compared school readiness in 31children with HIE treated with TH (without Cerebral Palsy; mean age 5 years 4 months) with 20 typically developing children without HIE (mean age 5 years 6 months).

RESULTS

Children with HIE scored significantly lower than typically developing children on fine motor skills, executive functions, memory and language.

CONCLUSION

While general cognitive abilities and attainment were in the normal range, our findings suggest those scores mask specific underlying difficulties identified by more focussed assessments. Children with HIE treated with TH may not be as 'school ready' as their typically developing classmates and may benefit from long-term follow-up until starting school.

Long-Term Outcomes of Perinatal Hypoxia and Asphyxia at an Early School Age

Background and Objectives: Late long-term outcomes of perinatal asphyxia (PA) in school-age are often unclear. To assess long-term outcomes at an early school age in children who had experienced perinatal hypoxia or asphyxia, where therapeutic hypothermia was not applied. Materials and Methods: The case group children were 8–9-year-old children (n = 32) who were born at full term and experienced hypoxia or asphyxia at birth, where therapeutic hypothermia (TH) was not applied. The control group consisted of 8–9-year-old children (n = 16) born without hypoxia. A structured neurological examination was performed at an early school age. The neuromotor function was assessed using the Gross Motor Function Classification System (GMFCS). Health-related quality-of-life was assessed using the Health Utilities Index (HUI) questionnaire. Intellectual abilities were assessed using the Wechsler Intelligence Scale for Children (WISC). Results: The case group, compared with controls, had significantly (p = 0.002) lower mean [SD] full-scale IQ (87(16.86) vs. 107(12.15)), verbal-scale IQ (89(17.45) vs. 105(11.55)), verbal comprehension index (89(17.36) vs. 105(10.74)), working memory index (89(15.68) vs. 104(11.84)), performance IQ (87(16.51) vs. 108(15.48)) and perceptual organization index (85(15.71) vs. 105(15.93)). We did not find any significant differences in the incidence of disorders of neurological examination, movement abilities and health-related quality of life at an early school age between the case and the control group children. Conclusion: In children who experienced perinatal asphyxia but did not have cerebral paralysis (CP), where therapeutic hypothermia was not applied, cognitive assessment scores at an early school age were significantly lower compared to those in the group of healthy children, and were at a low average level.

An Age-Specific Atlas for Delineation of White Matter Pathways in Children Aged 6-8 Years

Introduction

Diffusion MRI allows non-invasive assessment of white matter connectivity in typical development and of changes due to brain injury or pathology. Probabilistic white matter atlases allow diffusion metrics to be measured in specific white matter pathways, and are a critical component in spatial normalisation for group analysis. However, given the known developmental changes in white matter it may be sub-optimal to use an adult template when assessing data acquired from children.

Methods

By averaging subject-specific fibre bundles from 28 children aged from 6 to 8 years, we created an age-specific probabilistic white matter atlas for 12 major white matter tracts. Using both the newly developed and Johns Hopkins adult atlases, we compared the atlas to subject-specific fibre bundles in two independent validation cohorts, assessing accuracy in terms of volumetric overlap and measured diffusion metrics.

Results

Our age-specific atlas gave better overall performance than the adult atlas, achieving higher volumetric overlap with subject-specific fibre tracking and higher correlation of FA measurements with those measured from subject-specific fibre bundles. Specifically, estimates of FA values for cortico-spinal tract, uncinate fasciculus, forceps minor, cingulate gyrus part of the cingulum and anterior thalamic radiation were all significantly more accurate when estimated with an age-specific atlas.

Discussion

The age-specific atlas allows delineation of white matter tracts in children aged 6-8 years, without the need for tractography, more accurately than when normalising to an adult atlas. To our knowledge, this is the first publicly available probabilistic atlas of white matter tracts for this age group.

Recombinant erythropoietin does not augment hypothermic white matter protection after global cerebral ischaemia in near-term fetal sheep

Therapeutic hypothermia for hypoxic-ischaemic encephalopathy provides partial white matter protection. Recombinant erythropoietin reduces demyelination after hypoxia-ischaemia, but it is unclear whether adjunct erythropoietin treatment can further improve outcomes after therapeutic hypothermia. Term-equivalent fetal sheep received sham-ischaemia (n = 9) or cerebral ischaemia for 30 min (ischaemia-vehicle, n = 8), followed by intravenous infusion of recombinant erythropoietin (ischaemia-Epo, n = 8; 5000 IU/kg bolus dose, then 833.3 IU/kg/h), cerebral hypothermia (ischaemia-hypothermia, n = 8), or recombinant erythropoietin plus hypothermia (ischaemia-Epo-hypothermia, n = 8), from 3 to 72 h post-ischaemia. Foetal brains were harvested at 7 days after cerebral ischaemia. Ischaemia was associated with marked loss of total Olig2-positive oligodendrocytes with reduced density of myelin and linearity of the white matter tracts (P < 0.01), and microglial induction and increased caspase-3-positive apoptosis. Cerebral hypothermia improved the total number of oligodendrocytes and restored myelin basic protein (P < 0.01), whereas recombinant erythropoietin partially improved myelin basic protein density and tract linearity. Both interventions suppressed microgliosis and caspase-3 (P < 0.05). Co-treatment improved 2′,3′-cyclic-nucleotide 3′-phosphodiesterase-myelin density compared to hypothermia, but had no other additive effect. These findings suggest that although hypothermia and recombinant erythropoietin independently protect white matter after severe hypoxia-ischaemia, they have partially overlapping anti-inflammatory and anti-apoptotic effects, with little additive benefit of combination therapy.

The Term Newborn: Evaluation for Hypoxic-Ischemic Encephalopathy

Neonatal encephalopathy due to perinatal hypoxia-ischemia (hypoxic-ischemic encephalopathy [HIE]) occurs at a rate of 1 to 3 per 1000 live births. Therapeutic hypothermia is the standard of care and the only currently available therapy to reduce the risk of death or disability in newborns with moderate to severe HIE. Hypothermia therapy needs to be initiated within 6 hours after birth in order to provide the best chance for neuroprotection. All pediatricians and delivery room attendants should be trained to recognize encephalopathy and understand the eligibility criteria for treatment. The modified Sarnat examination is the most frequently used tool to assess the degree of encephalopathy and has six categories, each of which can have mild, moderate, severe abnormalities. Apart from historical and biochemical criteria, a neonate must have 3 of 6 categories scored in the moderate or severe range in order to qualify for hypothermia as was done in the randomized trials. Whether an infant qualifies or there is concern that an infant might have HIE, transfer to a center that can perform treatment should be initiated immediately. Hypothermia significantly reduces the risk of death or moderate to severe impairments at 2 years and at school age. On average, only 7 neonates need to be treated for one neonate to benefit. Although easy in concept, implementation of hypothermia does require expertise and should be carried out under the guidance of a neonatologist. If infants are passively cooled prior to transport, core temperature needs to be closely monitored with a target of 33.5°C ± 0.5°C. Maintenance of homeostasis is important in order to prevent conditions that may result in additional brain injury. Seizures are common in neonates with HIE, but electrographic seizures are rare in the first few hours after birth if the insult occurred during labor and delivery. Prophylactic antiepileptic drugs should not be administered. Brain monitoring in the form of electroencephalogram (EEG) and or amplitude-integrated EEG should be implemented as soon as possible to help with prognosis and to accurately diagnose seizures.