Two-Year Neurodevelopmental Outcomes After Mild Hypoxic Ischemic Encephalopathy in the Era of Therapeutic Hypothermia

Reduced Hippocampal Volumes in Children with History of Hypoxic Ischemic Encephalopathy after Therapeutic Hypothermia

Hypoxic ischemic encephalopathy (HIE) remains a significant cause of disability despite treatment with therapeutic hypothermia (TH). Many survive with more subtle deficits that affect daily functioning and school performance. We have previously shown an early indication of hippocampal changes in infants with HIE despite TH. The aim of this study was to evaluate the hippocampal volume via MRI and memory function at 5 years of age. A cohort of children followed from birth returned for a 5-year follow-up (n = 10 HIE treated with TH, n = 8 healthy controls). The children underwent brain MRI and neurodevelopmental testing to assess their brain volume, general development, and memory function. Children with HIE had smaller hippocampal volumes than the controls despite no differences in the total brain volume (p = 0.02). Children with HIE generally scored within the average range on developmental testing. Though there was no difference in the memory scores between these groups, there was a positive within-group correlation between the hippocampal volume and memory scores in children with HIE (sentence recall r = 0.66, p = 0.038). There was no relationship between newborn memory function and 5-year hippocampal size. Children with HIE treated with TH experienced significant and lasting changes to the hippocampus despite improvements in survival and severe disability. Future studies should target diminishing injury to the hippocampus to improve overall outcomes.

Neurosteroid pathway derangement in asphyctic infants treated with hypothermia: an untargeted metabolomic approach

BACKGROUND

The pathobiological mechanisms associated with perinatal asphyxia and hypoxic-ischemic encephalopathy are complex and poorly understood. The metabolic effects of therapeutic hypothermia have been partially explored.

METHODS

We conducted a single-center longitudinal study to investigate the metabolic effects of perinatal asphyxia and hypoxic-ischemic encephalopathy on the urinary metabolome of a group of 12 asphyctic infants over time compared to 22 matched healthy newborns, using untargeted metabolomics based on mass spectrometry.

FINDINGS

Over-representation pathway analysis identified the steroidogenesis pathway as being significantly disrupted, with reduced steroid levels in the first three days of life despite treatment with hypothermia. Comparison with matched healthy newborns showed that the urinary steroid content was lower in asphyctic infants before hypothermia. The lysine degradation and carnitine synthesis pathways were also significantly affected.

INTERPRETATION

Steroidogenesis is significantly disrupted in asphyctic infants compared to healthy newborns. Given how neurosteroids are involved in neuromodulation and neuroprotection, translational research is warranted on the potential role of neurosteroid-based intervention in asphyctic infants.

FUNDING

None.

Is Selective Head Cooling Combined with Whole-Body Cooling the Most Effective Hypothermia Method for Neonatal Hypoxic-Ischemic Encephalopathy?

This study aimed to compare combined hypothermia (CH) to the 2 classical therapeutic hypothermia (TH) methods selective head cooling (SHC) and whole-body cooling (WBC). This retrospective cohort study included neonates who underwent CH, SHC, and WBC between 2012 and 2020. Mean rectal temperature was maintained at 33.5 ± 0.5°C by cooling the head and the body in the CH group, at 34.5 ± 0.5°C by cooling the head in the SHC group, and at 33.5 ± 0.5°C by cooling the body in the WBC group. The groups were compared in terms of side effects, magnetic resonance imaging (MRI) scores, and status at discharge. The study included 60 neonates in the CH group, 112 in the WBC group, and 27 in the SHC group. There was no significant difference in side effects between the groups (p > 0.05). There was no significant difference in brain MRI scores between the groups (p > 0.05); however, gray matter, white matter, and total MRI scores in the CH group were lower than in the WBC group. Duration of hospitalization was shorter in the CH group than in the other two groups (p = 0.022). CH was not associated with more side effects than the two classical TH methods. In addition, some of these findings suggest that CH might result in better clinical outcome than the two classical TH methods.

All Care is Brain Care: Neuro-Focused Quality Improvement in the Neonatal Intensive Care Unit

Neonates requiring intensive care are in a critical period of brain development that coincides with the neonatal intensive care unit (NICU) hospitalization, placing these infants at high risk of brain injury and long-term neurodevelopmental impairment. Care in the NICU has the potential to be both harmful and protective to the developing brain. Neuro-focused quality improvement efforts address 3 main pillars of neuroprotective care: prevention of acquired injury, protection of normal maturation, and promotion of a positive environment. Despite challenges in measurement, many centers have shown success with consistent implementation of best and potentially better practices that may improve markers of brain health and neurodevelopment.

Low Apgar score and need for resuscitation increased the probability of receiving therapeutic hypothermia more strongly than acidosis at birth

AIM

The aim of this study was to investigate how individual markers for birth asphyxia, so-called A criteria, were associated with the probability of receiving therapeutic hypothermia.

METHODS

This population-based cohort study included 1336 live-born singleton term infants with any A criterion in the Stockholm-Gotland Region, Sweden during 2008 to 2014. The Swedish Neonatal Quality Register and National Patient Register were used for data collection. Results were presented as adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

RESULTS

There were 89 infants, 44 boys and 45 girls with mean gestational age 40.5 weeks, who received therapeutic hypothermia. Low Apgar score, aOR 12.44 (95% CI 5.99-25.86), and resuscitation, aOR 9.18 (95% CI 3.77-22.34), were strongly associated with therapeutic hypothermia. A pH <7.0 was less associated with the outcome, aOR 2.02 (95% CI 1.02-4.0). No infant who received therapeutic hypothermia fulfilled the criteria of base deficit ≥16 mmol/L only.

CONCLUSION

A low Apgar score of and/or a need for resuscitation is more relevant for identifying infants eligible for therapeutic hypothermia, compared to other A criteria. This knowledge could be used clinically to identify cases for review and avoid unnecessary monitoring of infants.

Irisin prevents hypoxic-ischemic brain damage in rats by inhibiting oxidative stress and protecting the blood-brain barrier

Hypoxic-ischemic encephalopathy (HIE) is associated with excessive inflammation, blood-brain barrier dysfunction, and oxidative stress. Irisin can reduce inflammation and ameliorate oxidative stress; however, its effects on hypoxic-ischemic brain damage in newborns are unknown. Newborn Sprague-Dawley rats were subjected to hypoxic-ischemic injury and irisin treatment. TUNEL staining assays, the albumin-Evans blue dye extravasation method, an antioxidants detection kit, quantitative reverse-transcriptase PCR, enzyme linked immunosorbent assay, Western blot analysis, immunohistochemistry, and electron microscopy were used to investigate the possible mechanisms underlying the prevention of HIE by irisin. We discovered that rats affected by HIE and administered irisin had lower levels of IL-6 (but not TNF-α or IL-1β) less oxidative stress, and enhanced blood-brain barrier integrity. Irisin can effectively attenuate brain damage by reducing oxidative stress and protecting the blood-brain barrier.

Extracellular Vesicle-microRNAs as Diagnostic Biomarkers in Preterm Neonates

Neonates born prematurely (<37 weeks of gestation) are at a significantly increased risk of developing inflammatory conditions associated with high mortality rates, including necrotizing enterocolitis, bronchopulmonary dysplasia, and hypoxic-ischemic brain damage. Recently, research has focused on characterizing the content of extracellular vesicles (EVs), particularly microRNAs (miRNAs), for diagnostic use. Here, we describe the most recent work on EVs-miRNAs biomarkers discovery for conditions that commonly affect premature neonates.

Neuroprotective effect of a novel brain-derived peptide, HIBDAP, against oxygen-glucose deprivation through inhibition of apoptosis in PC12 cells

BACKGROUND

The effect of a novel brain-derived peptide, hypoxic-ischemic brain damage associated peptide (HIBDAP), on apoptosis after oxygen-glucose deprivation (OGD) in PC12 cells was investigated.

METHODS

The HIBDAP sequence (HSQFIGYPITLFVEKER) was coupled with the carrier peptide of the transactivator of transcription (TAT) sequence (YGRKKRRQRRR). FITC-labelled TAT-HIBDAP was observed by fluorescence microscopy. After TAT-HIBDAP treatment and OGD treatment, the PC12 cell apoptosis rate was analysed using lactate dehydrogenase (LDH) leakage and Annexin V-fluorescein isothiocyanate (FITC) assays. Mitochondrial membrane potential (ΔΨm) was examined by fluorescence microscopy. Protein expression of apoptotic factors was examined by Western blotting.

RESULTS

FITC-labelled TAT-HIBDAP entered the PC12 cell nucleus. Compared with the OGD group, TAT-HIBDAP at low concentrations (1 µM, 5 µM, 10 µM) significantly reduced the apoptosis rate of PC12 cells (except at 20 µM); 5 µM TAT-HIBDAP had the most obvious effect. There were remarkable increases in ΔΨm at different concentrations (1 µM, 5 µM, 10 µM, 20 µM) of TAT-HIBDAP pretreatment, and 5 µM TAT-HIBDAP also had the most obvious effect. TAT-HIBDAP reversed the increased ratio of Bax/Bcl-2 and activation of Caspase-3 induced by OGD.

CONCLUSION

TAT-HIBDAP is resistant to OGD-induced PC12 cell apoptosis by regulating the Bax/Bcl-2/Caspase-3 pathway, which may provide a novel therapeutic strategy for neonatal HIBD.

The influence of late prematurity on the encephalopathy exam of infants with neonatal encephalopathy

BACKGROUND

Late preterm (LPT) infants are increasingly treated for hypoxic-ischemic encephalopathy (HIE). However, neurodevelopmental differences of LPT infants may independently influence the neurologic exam and confound care.

METHODS

Perinatal and outcome characteristics were extracted along with the worst autonomic and state/neuromuscular/reflex Sarnat components in a cross-section of infants with moderate/severe HIE. Infants were classified as late preterm (LPT, 34-36 weeks) or term (>36 weeks).

RESULTS

250 infants were identified, 55 were late preterm. LPT infants had lower mean gestational age and birthweight and greater length of stay (LOS). LPT infants had higher median scores for the Moro and respiratory autonomic components, but no difference in total score.

CONCLUSIONS

LPT infants had increased LOS, worse Moro reflex, and respiratory status, but no clinically or statistically significant differences in total Sarnat scores. Although it is important to note the impact of immaturity on the exam, it is unlikely to independently alter management.

Protective effect of isoflurane preconditioning on neurological function in rats with HIE

Hypoxic-ischemic encephalopathy (HIE) is an important cause of neonatal death and disability, which can lead to long-term neurological and motor dysfunction. Currently, inhalation anesthetics are widely used in surgery, and some studies have found that isoflurane (ISO) may have a positive effect on neuroprotection. In this paper, we investigated whether ISO pretreatment has a neuroprotective effect on the neurological function of HIE rats. Here, 7-day-old neonatal rats were randomly divided into a sham group, a hypoxic-ischemic (HI) group, and an ISO pretreatment (pretreatment) group. The pretreatment group was pretreated with 2% ISO for 1 h, followed by the HI group to establish an HI animal model. The HI‑induced neurological injury was evaluated by Zea‑Longa scores and triphenyltetrazolium (TTC) staining. Neuronal number and histomorphological changes were observed with Nissl staining and Hematoxylin-eosin (HE) staining. In addition, motor learning memory function was evaluated by the Morris water maze (MWM), the Y-maze, and the rotarod tests. HI induced severe neurological dysfunction, brain infarction, and cell apoptosis as well as obvious neuron loss in neonatal rats. In the MWM, the rats in the pretreatment group showed a decrease in escape latency (p = 0.042), indicating that pretreatment with ISO could improve the learning ability of HI rats. The results of Nissl staining showed that in the HI group, there was an irregular arrangement of neurons and nuclear fixation; however, the cell damage was significantly reduced and the total number of neurons was increased after ISO pretreatment (p < 0.001). In conclusion, ISO pretreatment improved cognitive function and attenuated HI-induced reduction of Nissl-positive cells and spatial memory impairment, suggesting that pretreatment with ISO before HI modeling could reduce neuronal cell death in the hippocampus after HI.

Brain injury following mild hypoxic-ischemic encephalopathy in neonates-Ten-year experience in a tertiary perinatal center

OBJECTIVE

We aimed to evaluate abnormal magnetic resonance imaging (MRI) findings in neonates with mild hypoxic-ischemic encephalopathy (HIE).

STUDY DESIGN

This was a single-center, retrospective study of mild HIE conducted from 2011 to 2020. Almost all neonates with mild HIE received management targeted to a temperature of 36 ± 0.5°C for 72 h and underwent MRI (135 of 145). We evaluated medical records and assessed amplitude-integrated electroencephalography (aEEG).

RESULT

All participants survived until discharge. Abnormal MRI findings were present in 23/135 (17%) neonates. The normal versus abnormal MRI-finding groups had similar characteristics, except discontinuous aEEG patterns (p = 0.002) and inotropic drugs (p = 0.035). Regression analyses showed discontinuous aEEG patterns (odds ratio = 19.3, 95% confidence interval=1.88-197, p = 0.013) being associated with higher odds of abnormal MRI findings.

CONCLUSION

Our study suggests that a discontinuous aEEG pattern is associated with abnormal MRI findings and can be used to discuss the definition of mild HIE.

Suppression of SAMSN1 contributes to neuroprotection in neonatal rats suffering from hypoxic-ischemic encephalopathy injury

This article aims to detect the effect of SAM domain, SH3 domain, and nuclear localization signal 1 (SAMSN1) in neonatal rats with neurological dysfunction induced by hypoxia and ischemia (HI). The HI model was created using 7-day postnatal rats. Zea-longa score was utilized to validate the neurological injury after HI. Then, the differentially expressed genes (DEGs) were detected by gene sequencing and bioinformatics analysis methods. The oxygen and glucose deprivation (OGD) models were established in the SY5Y cells and fetal human cortical neurons. In addition, SAMSN1-small interfering RNA, methyl thiazolyl tetrazolium assay, and cell growth curve were employed to evaluate the cell viability variation. Obviously, Zea-longa scores increased in rats with HI insult. Subsequently, SAMSN1 was screened out, and it was found that SAMSN1 was strikingly upregulated in SY5Y cells and fetal neurons post-OGD. Interestingly, we found that SAMSN1 silencing could markedly enhance cell viability and cell growth after OGD. These data suggested that downregulation of SAMSN1 may exert a neuroprotective effect on damaged neurons after HI by improving cell viability and cell survival, which provides a potential theoretical basis for clinical trials in the future to treat neonatal hypoxic-ischemic encephalopathy.

A Simplified Paradigm of Late Gestation Transient Prenatal Hypoxia to Investigate Functional and Structural Outcomes from a Developmental Hypoxic Insult

Late-gestation transient intrauterine hypoxia is a common cause of birth injury. It can lead to long-term neurodevelopmental disabilities even in the absence of gross anatomic injury. Currently, postnatal models of hypoxia-ischemia are most commonly used to study the effect of oxygen deprivation in the fetal brain. These models, however, are unable to take into account placental factors that influence the response to hypoxia, exhibit levels of cell death not seen in many human patients, and are unable to model preterm hypoxia. To address this gap in research, we have developed a protocol to induce transient hypoxia in fetal mice. A pregnant dam at gestational day 17.5 is placed into a hypoxia chamber. Over 30 min, the inspired oxygen is titrated from 21% (ambient air) to 5%. The dam remains in the chamber for up to 8 h, after which fetal brains can be collected or pups delivered for postnatal studies. This protocol recapitulates phenotypes seen in human patients exposed to transient in utero hypoxia and is readily reproducible by researchers. Graphical abstract.

Differences in standardized neonatal encephalopathy exam criteria may impact therapeutic hypothermia eligibility

BACKGROUND

Therapeutic hypothermia (TH) is routinely provided to those with moderate or severe neonatal encephalopathy (NE). Subtle differences exist in the standardized exams used to define NE severity. We aimed to assess if an infant's TH eligibility status differed if they were evaluated using either the NICHD/Neonatal Research Network's (NICHD-NRN) or TOBY/British Association of Perinatal Medicine's (TOBY-BAPM) neurological exam.

METHODS

Encephalopathic infants ≥36 weeks with evidence of perinatal asphyxia and complete documentation of the neurological exam &lt;6 h of age were included. TH eligibility using the NICHD-NRN and TOBY-BAPM criteria was determined based upon the documented exams.

RESULTS

Ninety-one encephalopathic infants were included. Despite good agreement between the two exams (κ = 0.715, p &lt; 0.001), TH eligibility differed between them (p &lt; 0.001). A total of 47 infants were deemed eligible by at least one method-46 using NICHD-NRN and 35 using TOBY-BAPM. Of the 12 infants eligible per NICHD-NRN, but ineligible per TOBY-BAPM, two developed electrographic seizures and seven demonstrated hypoxic-ischemic cerebral injury.

CONCLUSIONS

Both the NICHD-NRN and TOBY-BAPM exams are evidence-based. Despite this, there is a significant difference in the number of infants eligible for TH depending on which exam is used. The NICHD-NRN exam identifies a greater proportion as eligible.

IMPACT

There are subtle differences in the NICHD-NRN and TOBY-BAPM's encephalopathy exams used to determine eligibility for TH. This results in a significant difference in the proportion of infants determined to be eligible for TH depending on which encephalopathy exam is used. The NICHD-NRN encephalopathy exam identifies more infants as being eligible for TH than the TOBY-BAPM encephalopathy exam. This may result in different rates of cooling depending on which evidence-based neurological exam for evaluation of encephalopathy a center uses.

Effect of SARS-CoV-2 infection in neonates or in pregnancy on developmental outcomes at 21-24 months (SINEPOST): study protocol for a prospective cohort study

INTRODUCTION

Exposure to SARS-CoV-2 during pregnancy or in the neonatal period may impact fetal or neonatal brain development either through direct central nervous system infection or indirectly through the adverse effects of viral infection-related inflammation in the mother or newborn infant. This study aims to determine whether there are early neurodevelopmental effects of SARS-CoV-2 infection.

METHODS AND ANALYSIS

We will conduct a prospective national population-based cohort study of children aged 21-24 months who were born at term (≥37 weeks' gestation) between 1 March 2020 and 28 February 2021 and were either antenatally exposed, neonatally exposed or unexposed (comparison cohort) to SARS-CoV-2. Nationally, hospitals will identify and approach parents of children eligible for inclusion in the antenatally and neonatally exposed cohorts using information from the UK Obstetric Surveillance System (UKOSS) and British Paediatric Surveillance Unit (BPSU) national surveillance studies and will identify and approach eligible children for the comparison cohort through routine birth records. Parents will be asked to complete questionnaires to assess their child's development at 21-24 months of age. Outcome measures comprise the Ages and Stages Questionnaire, Third Edition (ASQ-3), Ages and Stages Questionnaire Social-Emotional, Second Edition (ASQ-SE-2), Liverpool respiratory symptoms questionnaire and questionnaire items to elicit information about healthcare usage. With parental consent, study data will be linked to routine health and education records for future follow-up. Regression models will compare ASQ-3 and ASQ-SE-2 scores and proportions, frequency of respiratory symptoms and healthcare usage between the exposed and comparison cohorts, adjusting for potential confounders.

ETHICS AND DISSEMINATION

Ethics approval was obtained from the London-Westminster Research Ethics Committee. Findings will be disseminated in scientific conference presentations and peer-reviewed publications.

ISRCTN REGISTRATION NUMBER

ISRCTN99910769.

Dexmedetomidine alleviates olfactory cognitive dysfunction by promoting neurogenesis in the subventricular zone of hypoxic-ischemic neonatal rats

Background: Hypoxic-ischemic brain damage (HIBD) is the main cause of neurological dysfunction in neonates. Olfactory cognitive function is important for feeding, the ability to detect hazardous situations and social relationships. However, only a few studies have investigated olfactory cognitive dysfunction in neonates with HIBD; furthermore, the specific mechanisms involved are yet to be elucidated. It has been reported that neurogenesis in the subventricular zone (SVZ) is linked to olfactory cognitive function. Recently, dexmedetomidine (DEX) has been shown to provide neuroprotection in neonates following HIBD. In the present study, we investigated whether DEX could improve olfactory cognitive dysfunction in neonatal rats following HIBD and attempted to determine the underlying mechanisms.

Methods: We induced HIBD in rats using the Rice–Vannucci model, and DEX (25 μg/kg, i.p.) was administered immediately after the induction of HIBD. Next, we used triphenyl tetrazolium chloride (TTC) staining and the Zea-longa score to assess the success of modelling. The levels of BDNF, TNF-α, IL-1β and IL-6 were determined by western blotting. Immunofluorescence staining was used to detect microglial activation and microglial M1/M2 polarization as well as to evaluate the extent of neurogenesis in the SVZ. To evaluate the olfactory cognitive function, the rats in each group were raised until post-natal days 28–35; then, we performed the buried food test and the olfactory memory test.

Results: Analysis showed that HIBD induced significant brain infarction, neurological deficits, and olfactory cognitive dysfunction. Furthermore, we found that DEX treatment significantly improved olfactory cognitive dysfunction in rat pups with HIBD. DEX treatment also increased the number of newly formed neuroblasts (BrdU/DCX) and neurons (BrdU/NeuN) in the SVZ by increasing the expression of BDNF in rat pups with HIBD. Furthermore, analysis showed that the neurogenic effects of DEX were possibly related to the inhibition of inflammation and the promotion of M1 to M2 conversion in the microglia.

Conclusion: Based on the present findings, DEX treatment could improve olfactory cognitive dysfunction in neonatal rats with HIBD by promoting neurogenesis in the SVZ and enhancing the expression of BDNF in the microglia. It was possible associated that DEX inhibited neuroinflammation and promoted M1 to M2 conversion in the microglia.

Urinary metabotypes of newborns with perinatal asphyxia undergoing therapeutic hypothermia

Perinatal asphyxia (PA) still occurs in about three to five per 1,000 deliveries in developed countries; 20% of these infants show hypoxic-ischemic encephalopathy (HIE) on brain magnetic resonance imaging (MRI). The aim of our study was to apply metabolomic analysis to newborns undergoing therapeutic hypothermia (TH) after PA to identify a distinct metabotype associated with the development of HIE on brain MRI. We enrolled 53 infants born at >35 weeks of gestation with PA: 21 of them showed HIE on brain MRI (the “HIE” group), and 32 did not (the “no HIE” group). Urine samples were collected at 24, 48 and 72 hours of TH. Metabolomic data were acquired using high-resolution mass spectrometry and analyzed with univariate and multivariate methods. Considering the first urines collected during TH, untargeted analysis found 111 relevant predictors capable of discriminating between the two groups. Of 35 metabolites showing independent discriminatory power, four have been well characterized: L-alanine, Creatine, L-3-methylhistidine, and L-lysine. The first three relate to cellular energy metabolism; their involvement suggests a multimodal derangement of cellular energy metabolism during PA/HIE. In addition, seven other metabolites with a lower annotation level (proline betaine, L-prolyl-L-phenylalanine, 2-methyl-dodecanedioic acid, S-(2-methylpropionyl)-dihydrolipoamide-E, 2,6 dimethylheptanoyl carnitine, Octanoylglucuronide, 19-hydroxyandrost-4-ene-3,17-dione) showed biological consistency with the clinical picture of PA. Moreover, 4 annotated metabolites (L-lysine, L-3-methylhistidine, 2-methyl-dodecanedioic acid, S-(2-methylpropionyl)-dihydrolipoamide-E) retained a significant difference between the “HIE” and “no HIE” groups during all the TH treatment. Our analysis identified a distinct urinary metabotype associated with pathological findings on MRI, and discovered 2 putative markers (L-lysine, L-3-methylhistidine) which may be useful for identifying neonates at risk of developing HIE after PA.

Polygraphic EEG Can Identify Asphyxiated Infants for Therapeutic Hypothermia and Predict Neurodevelopmental Outcomes

Background: Neonatal encephalopathy due to perinatal asphyxia is one of the leading causes of neonatal death and morbidity worldwide. The neurodevelopmental outcomes of asphyxiated neonates have considerably improved after therapeutic hypothermia (TH). The current challenge is to identify all newborns with encephalopathy at risk of cerebral lesions and subsequent disability within 6 h of life and who may be within the window period for treatment with TH. This study evaluated the neurodevelopmental outcomes in surviving asphyxiated neonates who did and did not receive TH, based on clinical and polygraphic electroencephalographic (p-EEG) criteria. Methods: The study included 139 asphyxiated newborns divided into two groups: 82 who received TH and 57 who were not cooled. TH was administered to asphyxiated newborns (gestational age ≥ 35 weeks, birth weight ≥ 1800 g) with encephalopathy of any grade and moderate-to-severe p-EEG abnormalities or seizures. Neurodevelopmental outcomes between the groups at 24 months of life and the risk factors for severe outcomes were assessed. Results: Severe neurodevelopmental impairment occurred in 10 (7.2%) out of the 139 enrolled neonates. Nine out of the 82 cooled neonates (11.0%) had severe neurodevelopmental impairment. All but one neonate (98.2%) who did not receive TH had normal outcomes. The multivariate logistic regression analysis showed that abnormal p-EEG patterns (OR: 27.6; IC: 2.8-267.6) and general movements (OR: 3.2; IC: 1.0-10.0) were significantly associated with severe neurodevelopmental impairment (area under ROC curve: 92.7%). Conclusion: The combination of clinical and p-EEG evaluations in hypoxic-ischemic encephalopathy contributed to a more accurate selection of patients treated with therapeutic hypothermia. When administered to infants with moderate to severe p-EEG abnormalities, TH prevents approximately 90% of severe neurodevelopmental impairment after any grade of hypoxic-ischemic encephalopathy.

Opioid analgesia and temperature regulation are associated with EEG background activity and MRI outcomes in neonates with mild-to-moderate hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia

BACKGROUND

Therapeutic hypothermia (TH) without sedation may lead to discomfort, which may be associated with adverse consequences in neonates with hypoxic-ischemic encephalopathy (HIE). The aim of this study was to assess the association between level of exposure to opioids and temperature, with electroencephalography (EEG) background activity post-TH and magnetic resonance imaging (MRI) brain injury in neonates with HIE.

METHODS

Thirty-one neonates with mild-to-moderate HIE who underwent TH were identified. MRIs were reviewed for presence of brain injury. Quantitative EEG background features including EEG discontinuity index and spectral power densities were calculated during rewarming and post-rewarming periods. Dose of opioids administered during TH and temperatures were collected from the medical charts. Multivariable linear and logistic regression analyses were conducted to assess the associations between cumulative dose of opioids and temperature with EEG background and MRI while adjusting for markers of HIE severity.

RESULTS

Higher opioid doses (β = -0.21, p = 0.02) and reduced skin temperature (β = 0.14, p < 0.01) were associated with lower EEG discontinuity index recorded post-TH. Higher opioid doses (β = 0.75, p = 0.01) and reduced skin temperature (β = -0.39, p = 0.02) were also associated with higher EEG Delta power post-TH. MRI brain injury was observed in 14 patients (45%). In adjusted regression analyses, higher opioid doses (OR = 0.00; 95%CI: 0-0.19; p = 0.01), reduced skin temperature (OR = 41.19; 95%CI: 2.27-747.86; p = 0.01) and reduced cooling device output temperature (OR = 1.91; 95%CI: 1.05-3.48; p = 0.04) showed an association with lower odds of brain injury.

CONCLUSIONS

Higher level of exposure to opioids and reduced skin temperature during TH in mild-to-moderate HIE were associated with improved EEG background activity post-TH. Moreover, higher exposure to opioids, reduced skin temperature and reduced device output temperature were associated with lower odds of brain injury on MRI.

Cerebral perfusion changes of the basal ganglia and thalami in full-term neonates with hypoxic-ischaemic encephalopathy: a three-dimensional pseudo continuous arterial spin labelling perfusion magnetic resonance imaging study

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE) is one of the common causes of neurological injury in full-term neonates following perinatal asphyxia. The conventional magnetic resonance technique has low sensitivity in detecting variations in cerebral blood flow in patients with HIE.

OBJECTIVE

This article evaluates the clinical diagnostic value of three-dimensional pseudo-continuous arterial spin labelling (3-D pcASL) perfusion magnetic resonance imaging (MRI) for early prediction of neurobehavioral outcomes in full-term neonates with HIE.

MATERIALS AND METHODS

All neonates diagnosed with HIE underwent MRI (conventional and 3-D pcASL perfusion MRI). Cerebral blood flow values were measured in the basal ganglia (caudate nuclei, lenticular nuclei), thalami and white matter regions (frontal lobes, corona radiata). After 1-month follow-up, the Neonatal Behavioral Neurological Assessment scores were used to divide patients into favourable outcome group versus adverse outcome group.

RESULTS

Twenty-three patients were enrolled in this study. There were no statistical differences between the symmetrical cerebral blood flow values of bilateral basal ganglia, thalami and white matter regions. However, the cerebral blood flow values of grey matter nuclei were higher than the white matter regions. The average value of cerebral blood flow in the basal ganglia and thalami in the adverse outcome group was 37.28±6.42 ml/100 g/min, which is greater than the favourable outcome group (22.55 ± 3.21 ml/100 g/min) (P<0.01). The area under the curve (AUC) of 3-D pcASL perfusion MRI was 0.992 with a cutoff value of 28.75 ml/100 g/min, with a Youden's index of 0.9231. The sensitivity and specificity were 92.3% and 100%, respectively.

CONCLUSION

The 3-D pcASL demonstrated higher perfusion alteration in the basal ganglia and thalami of neonatal HIE with adverse outcomes. The 3-D pcASL perfusion MRI has the potential to predict neurobehavioral outcomes of neonates with HIE.

Hypocapnia in early hours of life is associated with brain injury in moderate to severe neonatal encephalopathy

OBJECTIVE

To evaluate the association between hypocapnia within the first 24 h of life and brain injury assessed by a detailed MRI scoring system in infants receiving therapeutic hypothermia (TH) for neonatal encephalopathy (NE) stratified by the stage of NE.

STUDY DESIGN

This retrospective cohort study included infants who received TH for mild to severe NE.

RESULTS

188 infants were included in the study with 48% having mild and 52% moderate-severe NE. Infants with moderate-severe NE spent more time in hypocapnia (PCO₂ ≤ 35 mmHg) and presented with more severe brain injury on MRI compared to mild cases. The MRI injury score increased by 6% for each extra hour spent in hypocapnic range in infants with moderate-severe NE. There was no association between hypocapnia and injury scores in mild cases.

CONCLUSION

In infants with moderate-severe NE, the hours spent in hypocapnia was an independent predictor of brain injury.

The protective effect of MiR-27a on the neonatal hypoxic-ischemic encephalopathy by targeting FOXO1 in rats

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE), a kind of hypoxic-ischemic brain damage caused by perinatal asphyxia, is the most crucial cause of neonatal death and long-term neurological dysfunction in children. We aimed to investigate the protective effects of micro (mi)R-27a on HIE in neonatal rats.

METHODS

A rat model of neonatal HIE was constructed by modification of the Rice-Vannucci model. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to test the expressions of miR-27a, FOXO1 messenger RNA (mRNA), interleukin-1β (IL-1β) mRNA, and tumor necrosis factor-α (TNF-α) mRNA, and western blot was applied to test the expression of FOXO1. In order to overexpress miR-27a, an intracerebroventricular injection (i.c.v) of miR-27a mimic was administered. We adopted 2,3,5-triphenytetrazolium chloride (TTC) staining and brain water content measurement to test the effects of miR-27a on the infarcted volume and edema in brain after HIE. Flow cytometry (FCM) analysis was applied to test the effects of miR-27a on the infiltrated peripheral immune cells in the rat brains after HIE.

RESULTS

We successfully established a rat model of neonatal HIE. It was revealed that the expressions of miR-27a decreased gradually after HIE, however, the expressions of FOXO1 mRNA increased. After injection of the miR-27a mimic, the expression of miR-27a in the rat HIE model brains was significantly upregulated, however, the expression of FOXO1 was robustly downregulated. Both TTC staining and brain water content showed that the infarcted volume and brain edema was markedly increased after HIE. Interestingly, the overexpression of miR-27a reduced the infarcted volume and edema induced by HIE. Additionally, RT-qPCR and FCM analysis showed that HIE lead to increases of IL-1β, TNF-α, and infiltrated immune cells. Overexpression of miR-27a could reduce the expressions of IL-1β mRNA and TNF-α mRNA, and the cell numbers of infiltrated peripheral macrophages and neutrophils in the brain.

CONCLUSIONS

MiR-27a plays protective roles by reducing infarct volume and brain edema, and inhibiting inflammatory factors and infiltrated peripheral immune cells by targeting FOXO1 in neonatal HIE rats.

Variations in practices and outcomes of neonates with hypoxic ischemic encephalopathy treated with therapeutic hypothermia across tertiary NICUs in Canada

OBJECTIVE

To characterize variations in practices and outcomes for neonates with hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH) across Canadian tertiary Neonatal Intensive Care Units (NICUs).

STUDY DESIGN

Retrospective study of neonates admitted for HIE and treated with TH in 24 tertiary NICUs from the Canadian Neonatal Network, 2010-2020. The two primary outcomes of mortality before discharge and MRI-detected brain injury were compared across NICUs using adjusted standardized ratios (SR) with 95% CI.

RESULTS

Of the 3261 neonates that received TH, 367 (11%) died and 1033 (37%) of the 2822 with MRI results had brain injury. Overall, rates varied significantly across NICUs for mortality (range 5-17%) and brain injury (range 28-51%). Significant variations in use of inotropes, inhaled nitric oxide, blood products, and feeding during TH were identified (p values < 0.01).

CONCLUSION

Significant variations exist in practices and outcomes of HIE neonates treated with hypothermia across Canada.

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

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

Rationale for the Use of Cord Blood in Hypoxic-Ischaemic Encephalopathy

Hypoxic-ischaemic encephalopathy (HIE) is a severe complication of asphyxia at birth. Therapeutic hypothermia, the standard method for HIE prevention, is effective in only 50% of the cases. As the understanding of the immunological basis of these changes increases, experiments have begun with the use of cord blood (CB) because of its neuroprotective properties. Mechanisms for the neuroprotective effects of CB stem cells include antiapoptotic and anti-inflammatory actions, stimulation of angiogenesis, production of trophic factors, and mitochondrial donation. In several animal models of HIE, CB decreased oxidative stress, cell death markers, CD4+ T cell infiltration, and microglial activation; restored normal brain metabolic activity; promoted neurogenesis; improved myelination; and increased the proportion of mature oligodendrocytes, neuron numbers in the motor cortex and somatosensory cortex, and brain weight. These observations translate into motor strength, limb function, gait, and cognitive function and behaviour. In humans, the efficacy and safety of CB administration were reported in a few early clinical studies which confirmed the feasibility and safety of this intervention for up to 10 years. The results of these studies showed an improvement in the developmental outcomes over hypothermia. Two phase-2 clinical studies are ongoing under the United States regulations, namely one controlled study and one blinded study.

Deficits in Seizure Threshold and Other Behaviors in Adult Mice without Gross Neuroanatomic Injury after Late Gestation Transient Prenatal Hypoxia

Intrauterine hypoxia is a common cause of brain injury in children resulting in a broad spectrum of long-term neurodevelopmental sequela, including life-long disabilities that can occur even in the absence of severe neuroanatomic damage. Postnatal hypoxia-ischemia rodent models are commonly used to understand the effects of ischemia and transient hypoxia on the developing brain. Postnatal models, however, have some limitations. First, they do not test the impact of placental pathologies on outcomes from hypoxia. Second, they primarily recapitulate severe injury because they provoke substantial cell death, which is not seen in children with mild hypoxic injury. Lastly, they do not model preterm hypoxic injury. Prenatal models of hypoxia in mice may allow us to address some of these limitations to expand our understanding of developmental brain injury. The published rodent models of prenatal hypoxia employ multiple days of hypoxic exposure or complicated surgical procedures, making these models challenging to perform consistently in mice. Furthermore, large animal models suggest that transient prenatal hypoxia without ischemia is sufficient to lead to significant functional impairment to the developing brain. However, these large animal studies are resource-intensive and not readily amenable to mechanistic molecular studies. Therefore, here we characterized the effect of late gestation (embryonic day 17.5) transient prenatal hypoxia (5% inspired oxygen) on long-term anatomical and neurodevelopmental outcomes in mice. Late gestation transient prenatal hypoxia increased hypoxia-inducible factor 1 alpha protein levels (a marker of hypoxic exposure) in the fetal brain. Hypoxia exposure predisposed animals to decreased weight at postnatal day 2, which normalized by day 8. However, hypoxia did not affect gestational age at birth, litter size at birth, or pup survival. No differences in fetal brain cell death or long-term gray or white matter changes resulted from hypoxia. Animals exposed to prenatal hypoxia did have several long-term functional consequences, including sex-dichotomous changes. Hypoxia exposure was associated with a decreased seizure threshold and abnormalities in hindlimb strength and repetitive behaviors in males and females. Males exposed to hypoxia had increased anxiety-related deficits, whereas females had deficits in social interaction. Neither sex developed any motor or visual learning deficits. This study demonstrates that late gestation transient prenatal hypoxia in mice is a simple, clinically relevant paradigm for studying putative environmental and genetic modulators of the long-term effects of hypoxia on the developing brain.

Perinatal outcome and need of care for term asphyxiated newborns without moderate or severe hypoxic-ischemic encephalopathy

AIM

Birth asphyxia can lead to organ dysfunction, varying from isolated biological acidosis to hypoxic-ischemic encephalopathy (HIE). Pathophysiology of moderate or severe HIE is now well known and guidelines exist regarding the care required in this situation. However, for newborns without moderate or severe HIE, no consensus is available. Our objective was to describe the immediate neonatal consequences and need for care of asphyxiated newborns without moderate or severe HIE.

METHODS

Multicentre retrospective study from January 2015 to December 2017 in two academic centres, including neonates ≥37 gestational weeks with pathological foetal acidemia (umbilical arterial pH<7.00 and/or lactate≥10 mmol/L).

RESULTS

Among 18 550 births, 161 (0.9%) had pathological foetal acidemia. 142 (88.0%) were not diagnosed with moderate or severe HIE. Among them, 82 (58.0%) were hospitalised. 13 (9.0%) had respiratory failure and required nutritional support. 100 (70.0%) underwent blood sampling, which showed at least one biological anomaly in 66 (66.0%) of cases.

CONCLUSION

Newborns born with pathological foetal acidemia without the occurrence of moderate or severe HIE had metabolic disorders and could need organ support. A prospective study describing this vulnerable population would help to establish consensus guidelines for the management of this population.

Association of Acute Respiratory Failure in Early Childhood With Long-term Neurocognitive Outcomes

IMPORTANCE

Approximately 23 700 US children undergo invasive mechanical ventilation for acute respiratory failure annually, with unknown long-term effects on neurocognitive function.

OBJECTIVE

To evaluate neurocognitive outcomes of children who survive pediatric intensive care unit (PICU) hospitalization for acute respiratory failure compared with their biological siblings.

DESIGN, SETTING, AND PARTICIPANTS

Prospective sibling-matched cohort study conducted at 31 US PICUs and associated neuropsychology testing centers. Patients were 8 years or younger with a Pediatric Cerebral Performance Category score of 1 (normal) before PICU admission and less than or equal to 3 (no worse than moderate neurocognitive dysfunction) at PICU discharge, excluding patients with a history of neurocognitive deficits or who were readmitted and underwent mechanical ventilation. Biological siblings were aged 4 to 16 years at testing, with Pediatric Cerebral Performance Category score of 1 and no history of mechanical ventilation or general anesthesia. A total of 121 sibling pairs were enrolled from September 2, 2014, to December 13, 2017, and underwent neurocognitive testing starting March 14, 2015. The date of the final follow-up was November 6, 2018.

EXPOSURES

Critical illness and PICU treatment for acute respiratory failure.

MAIN OUTCOMES AND MEASURES

The primary outcome was IQ, estimated by the age-appropriate Vocabulary and Block Design subtests of the Wechsler Intelligence Scale. Secondary outcomes included measures of attention, processing speed, learning and memory, visuospatial skills, motor skills, language, and executive function. Evaluations occurred 3 to 8 years after hospital discharge.

RESULTS

Patients (n = 121; 55 [45%] female patients) underwent PICU care at a median (IQR) age of 1.0 (0.2-3.2) years, received a median (IQR) of 5.5 (3.1-7.7) days of invasive mechanical ventilation, and were tested at a median (IQR) age of 6.6 (5.4-9.1) years. Matched siblings (n = 121; 72 [60%] female siblings) were tested at a median (IQR) age of 8.4 (7.0-10.2) years. Patients had a lower mean estimated IQ than matched siblings (101.5 vs 104.3; mean difference, -2.8 [95% CI, -5.4 to -0.2]). Among secondary outcomes, patients had significantly lower scores than matched siblings on nonverbal memory (mean difference, -0.9 [95% CI, -1.6 to -0.3]), visuospatial skills (mean difference, -0.9 [95% CI, -1.8 to -0.1]), and fine motor control (mean difference, -3.1 [95% CI, -4.9 to -1.4]) and significantly higher scores on processing speed (mean difference, 4.4 [95% CI, 0.2-8.5]). There were no significant differences in the remaining secondary outcomes, including attention, verbal memory, expressive language, and executive function.

CONCLUSIONS AND RELEVANCE

Among children, survival of PICU hospitalization for respiratory failure and discharge without severe cognitive dysfunction was associated with significantly lower subsequent IQ scores compared with matched siblings. However, the magnitude of the difference was small and of uncertain clinical importance.

Mechanisms of Vitamin C Regulating Immune and Inflammation Associated with Neonatal Hypoxic-Ischemic Encephalopathy Based on Network Pharmacology and Molecular Simulation Technology

Background

There are still controversies about the curative effect of vitamin C in treating HIE, and its mechanism of action is not entirely clear. This study is designed to explore the potential molecular mechanism of vitamin C in treating neonatal hypoxic ischemic encephalopathy (HIE).

Methods

The effect targets of vitamin C and the pathogenic targets of neonatal HIE were obtained via retrieval of public databases to screen out the molecular targets of vitamin C acting on neonatal HIE. Gene Ontology (GO) functional annotations and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed on the main targets. Vitamin C and the optimum target structural components are subjected to molecular docking and molecular dynamics simulation analysis via computer software so as to verify their binding activity and stability.

Result

Based on 16 overlapping targets of vitamin C and HIE, seven main targets were identified in this study. According to GO and KEGG analysis, molecular functions (top 25 items) and signal pathways (21 items) related to inflammatory reaction, immune response, and cell transcriptional control may be potential pathways for vitamin C to treat neonatal HIE. Molecular docking and molecular dynamics simulation were adopted to definitively determine the 4 optimum core target spots.

Conclusion

The efficacy of vitamin C on HIE is involved in the immunoregulation and inflammation-related functional processes and signal pathways. These molecular mechanisms, including core targets, will contribute to the clinical practice of neonatal HIE in the future.

Alterations in motor functional connectivity in Neonatal Hypoxic Ischemic Encephalopathy

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE) is the result of global hypoxic-ischemic brain injury in neonates due to asphyxia during birth and is one of the most common causes of severe, long-term neurologic deficits in children. Methods: Resting state fMRI (rs-fMRI) was used to assess potential functional disruptions in the primary and association motor areas in HIE neonates (n = 16) compared to healthy controls (n = 11).

RESULTS

Results demonstrate reduced intra-hemispheric resting state functional connectivity (rs-FC) between primary motor regions (upper extremity and facial motor regions) as well as reduced inter-hemispheric rs-FC in the HIE group. In addition, HIE neonates demonstrated increased rs-FC between motor regions and frontal, temporal and parietal cortices but decreased rs-FC with the cerebellum.

DISCUSSION

These preliminary results provide initial evidence for the disruption of functional communication with the motor network in neonates with HIE. Further studies are necessary to both validate these findings in a larger dataset as well as to determine if rs-fMRI measurements collected at birth may have the potential to serve as a prognostic marker in addition to the traditional combination of clinical measurements and conventional MRI.

Profile of minor neurological findings after perinatal asphyxia

Aim

To characterise the spectrum of findings in sequential neurological examinations, general movements (GM) assessment and magnetic resonance imaging (MRI) of infants with perinatal asphyxia.

Methods

The prospective cohort study of term infants with perinatal asphyxia treated at Helsinki University Hospital's neonatal units in 2016–2020 used Hammersmith Neonatal Neurological Examination (HNNE) and brain MRI at 2 weeks and Hammersmith Infant Neurological Examination (HINE) and GM assessment at 3 months of age.

Results

Analysis included 50 infants: 33 displaying perinatal asphyxia without hypoxic‐ischaemic encephalopathy (HIE), seven with HIE1 and 10 with HIE2. Of the infants with atypical HNNE findings, 24/25 perinatal asphyxia without HIE cases, 5/6 HIE1 cases and all 10 HIE2 cases showed atypical findings in the HINE. The HINE identified atypical spontaneous movements significantly more often in infants with white matter T2 hyperintensity.

Conclusion

In this cohort, most infants with perinatal asphyxia, with or without HIE, presented atypical neurological findings in sequential examinations. The profile of neurological findings for children with perinatal asphyxia without HIE resembled that of children with HIE. White matter T2 hyperintensity was associated with atypical spontaneous movements in the HINE and was a frequent MRI finding also in perinatal asphyxia without HIE.

Comparison of numerical and standard sarnat grading using the NICHD and SIBEN methods

OBJECTIVE

The NICHD and SIBEN assessments are adapted from the Sarnat grade, and used to determine severity of neonatal encephalopathy (NE). We compare NICHD and SIBEN methods, and their ability to define a minimum threshold associated with significant cerebral injury.

STUDY DESIGN

Between 2016 and 2019, 145 infants with NE (77-mild; 65-moderate; 3-severe) were included. NICHD and SIBEN grade and numerical scores were assigned. Kappa scores described agreement between methods, and ROC curves their ability to predict MR injury.

RESULTS

Good agreement existed between grading systems (K = 0.86). SIBEN defined more infants as moderate, and less as mild, than NICHD (p < 0.001). Both numerical scores were superior to standard grades in predicting MR injury.

CONCLUSION

Despite good agreement between methods, SIBEN defines more infants as moderate NE. Both numerical scores were superior to standard grade, and comparable to each other, in defining a minimum threshold for cerebral injury. Further assessment contrasting their predictive ability for long-term outcome is required.

Impact of Cerebral Oxygen Saturation Monitoring on Short-term Neurodevelopmental Outcomes in Neonates with Encephalopathy - A Prospective Cohort Study

BACKGROUND

Near-infrared spectroscopy (NIRS) has been used for monitoring cerebral oxygen saturation (rSO2) in neonates. There is a lack of data from low-middle income countries (LMIC) setting of cerebral rSO2 in neonates with encephalopathy of diverse etiologies. This study aimed to monitor cerebral rSO2 using NIRS in encephalopathic neonates to maintain the rSO2 between 55 to 85 % in the first 72 hours of admission to improve short-term neurodevelopmental outcomes (NDO).

MATERIALS AND METHODS

This prospective cohort study enrolled encephalopathic neonates with hypoxic- ischemic encephalopathy (HIE) and non-HIE etiologies into 8 clinical categories. The cerebral rSO2 was monitored and targeted to be between 55 to 85 %, with predefined actions and management alterations over 72 hours. The neurodevelopmental assessment was conducted at 3, 6, and 9-12 months corrected age. Moreover, the motor and mental developmental quotients (MoDQ) (MeDQ) were recorded and compared to historical control.

RESULTS

A total of 120 neonates were enrolled and assessed for NDO. The MoDQ (mean ± SD) was 92.55 ± 14.85, 93.80 ± 13.20, 91.02 ± 12.69 and MeDQ (mean ± SD) was 91.80 ± 12.98, 91.80 ± 13.69, 88.41 ± 11.60 at 3, 6 and 9-12 months. The MoDQ and MeDQ scores of the historic cohort at 12 months were 86.35 ± 20.34 and 86.58 ± 18.27. The mean difference [MD (95 %CI)] for MoDQ was - 4.670 (- 8.48 to - 0.85) (p=0.0165) and for MeDQ was - 1.83 (- 5.26 to 1.6) (p=0.29). There was a negative correlation between the composite developmental quotient (CoDQ) with mean rSO2 and a positive correlation with cerebral fractional tissue oxygen extraction (CFTOE). Neonates with HIE and neonatal encephalopathy (NE) (n=37/120) had the lowest motor and mental DQ on neurodevelopmental assessment. Clinical categories, neonatal meningitis (NM), and intraventricular hemorrhage (IVH) improved in DQ scores over the study period.

CONCLUSION

Monitoring and maintaining cerebral rSO2 between 55-85 % through appropriate management changes improved neurodevelopmental scores at the 12-month follow-up in neonates with encephalopathy caused by varied etiologies.

Challenges in developing therapeutic strategies for mild neonatal encephalopathy

There is increasing evidence that infants with mild neonatal encephalopathy (NE) have significant risks of mortality, brain injury and adverse neurodevelopmental outcomes. In the era of therapeutic hypothermia, infants need to be diagnosed within 6 hours of birth, corresponding with the window of opportunity for treatment of moderate to severe NE, compared to the retrospective grading over 2 to 3 days, typically with imaging and formal electroencephalographic assessment in the pre-hypothermia era. This shift in diagnosis may have increased the apparent prevalence of brain damage and poor neurological outcomes seen in infants with mild NE in the era of hypothermia. Abnormal short term outcomes observed in infants with mild NE include seizures, abnormal neurologic examination at discharge, abnormal brain magnetic resonance imaging and difficulty feeding. At 2 to 3 years of age, mild NE has been associated with an increased risk of autism, language and cognitive deficits. There are no approved treatment strategies for these infants as they were not included in the initial randomized controlled trials for therapeutic hypothermia. However, there is already therapeutic creep, with many centers treating infants with mild NE despite the limited evidence for its safety and efficacy. The optimal duration of treatment and therapeutic window of opportunity for effective treatment need to be specifically established for mild NE as the evolution of injury is likely to be slower, based on preclinical data. Randomized controlled trials of therapeutic hypothermia for infants with mild NE are urgently required to establish the safety and efficacy of treatment. This review will examine the evidence for adverse outcomes after mild NE and dissect some of the challenges in developing therapeutic strategies for mild NE, before analyzing the evidence for therapeutic hypothermia and other strategies for treatment of these infants.

Application of amide proton transfer imaging for the diagnosis of neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

This study aimed to evaluate cerebral amide proton transfer signal intensity (SI) among controls, hypoxic-ischemic encephalopathy (HIE) neonates with normal conventional magnetic resonance imaging (HIE/MRI-) findings, and HIE neonates with abnormal conventional MRI (HIE/MRI+) findings.

METHODS

Forty neonates diagnosed with neonatal HIE and sixteen normal neonates were evaluated. All neonates underwent conventional MRI scans and APT imaging. Cerebral APT SIs were compared to identify cerebral regions with significant APT changes among sixteen controls, thirteen HIE/MRI- patients, and twenty-seven HIE/MRI+ patients.

RESULTS

Significantly increased APT SIs were observed in the HIE/MRI- group compared with controls, in the left insula, right occipital lobe, left cingulate gyrus (posterior part), and corpus callosum. Significantly increased APT SIs were found in the HIE/MRI+ group compared with controls, in the right anterior temporal lobe (medial part), anterior parts of the right parahippocampal and ambient gyri, left superior temporal gyrus (middle part), left insula, left cingulate gyrus (posterior part), and right lentiform nucleus. No significant APT SI differences were observed in the cerebellum and brainstem among the three groups.

CONCLUSION

Amide proton transfer imaging plays an important role in detecting hypoxic-ischemic encephalopathy regardless of conventional MRI findings. Changes in APT signal intensity may provide important insights into the characterization of the cerebral internal environment. This study suggests that APT imaging could be used as a complement to conventional MRI in the detection of hypoxic-ischemic encephalopathy in clinical practice.

Research advances in the role of endogenous neurogenesis on neonatal hypoxic-ischemic brain damage

Hypoxic-ischemic brain damage (HIBD) is the main cause of perinatal mortality and neurologic complications in neonates, but it remains difficult to cure due to scarce treatments and complex molecular mechanisms remaining incompletely explained. Recent, mounting evidence shows that endogenous neurogenesis can improve neonatal neurological dysfunction post-HIBD. However, the capacity for spontaneous endogenous neurogenesis is limited and insufficient for replacing neurons lost to brain damage. Therefore, it is of great clinical value and social significance to seek therapeutic techniques that promote endogenous neurogenesis, to reduce neonatal neurological dysfunction from HIBD. This review summarizes the known neuroprotective effects of, and treatments targeting, endogenous neurogenesis following neonatal HIBD, to provide available targets and directions and a theoretical basis for the treatment of neonatal neurological dysfunction from HIBD.

Hypoxic ischemic encephalopathy in offspring of immigrant women in Sweden: A population-based cohort study

INTRODUCTION

One in four women giving birth in Sweden is foreign-born. Immigrant status has been suggested as a risk factor for adverse perinatal outcomes. It is not known if infants to foreign-born women have an increased risk of severe birth asphyxia, or which factors might mediate such association.

MATERIAL AND METHODS

A population-based cohort study of 726 730 live births at 36 weeks of gestation or more in Sweden in 2009-2015. The exposure was maternal country of birth, grouped according to the World Bank country classification: low-, lower-middle, upper-middle, and high-income economies. The main outcome was neonatal hypoxic ischemic encephalopathy (HIE). The outcome was estimated by severity and classified as non-hypothermia-treated HIE, representing mainly mild cases, and hypothermia-treated HIE, representing moderate to severe cases. A secondary outcome was low Apgar score at 5 minutes, defined as <7 or <4. Odds ratios with 95% CI were calculated, using Swedish-born women as the reference. Structural equation modeling was used to investigate potential mediation of known antepartum risk factors.

RESULTS

A total of 854 infants were diagnosed with HIE and 398 received therapeutic hypothermia. Offspring of mothers born in low-income countries had the highest incidences of HIE and low Apgar score, with an incidence of therapeutic hypothermia of 1.1 per 1000. Compared with offspring of Swedish-born mothers, these neonates had an almost two-fold increased risk of HIE, with or without hypothermia treatment (odds ratio 1.7; 95% CI 1.2-2.7 and odds ratio 1.7; 95% CI 1.2-2.6, respectively), and a 2- to 3-fold increased risk of low Apgar score. The structural equation model analysis indicated an exclusive direct effect of country of birth on HIE. Factors reflecting socio-economic status mediated a small proportion of the risk of Apgar score <7 at 5 minutes.

CONCLUSIONS

Offspring of women born in low-income countries had associations with severe birth asphyxia, with increased risk of both HIE and low Apgar score at 5 minutes. The associations seemed only to be marginally mediated by other antepartum factors. The associations are complex and further studies are needed to find explanatory and potentially preventable factors.

Assessing Creatine Supplementation for Neuroprotection against Perinatal Hypoxic-Ischaemic Encephalopathy: A Systematic Review of Perinatal and Adult Pre-Clinical Studies

There is an important unmet need to develop interventions that improve outcomes of hypoxic-ischaemic encephalopathy (HIE). Creatine has emerged as a promising neuroprotective agent. Our objective was to systematically evaluate the preclinical animal studies that used creatine for perinatal neuroprotection, and to identify knowledge gaps that need to be addressed before creatine can be considered for pragmatic clinical trials for HIE.

METHODS

We reviewed preclinical studies up to 20 September 2021 using PubMed, EMBASE and OVID MEDLINE databases. The SYRCLE risk of bias assessment tool was utilized.

RESULTS

Seventeen studies were identified. Dietary creatine was the most common administration route. Cerebral creatine loading was age-dependent with near term/term-equivalent studies reporting higher increases in creatine/phosphocreatine compared to adolescent-adult equivalent studies. Most studies did not control for sex, study long-term histological and functional outcomes, or test creatine post-HI. None of the perinatal studies that suggested benefit directly controlled core body temperature (a known confounder) and many did not clearly state controlling for potential study bias.

CONCLUSION

Creatine is a promising neuroprotective intervention for HIE. However, this systematic review reveals key knowledge gaps and improvements to preclinical studies that must be addressed before creatine can be trailed for neuroprotection of the human fetus/neonate.

Wavelet-based neurovascular coupling can predict brain abnormalities in neonatal encephalopathy

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of morbidity and mortality in neonates, but quantitative methods to predict outcomes early in their course of illness remain elusive. Real-time physiologic biomarkers of neurologic injury are needed in order to predict which neonates will benefit from therapies. Neurovascular coupling (NVC) describes the correlation of neural activity with cerebral blood flow, and the degree of impairment could predict those at risk for poor outcomes.

OBJECTIVE

To determine if neurovascular coupling (NVC) calculated in the first 24-hours of life based on wavelet transform coherence analysis (WTC) of near-infrared spectroscopy (NIRS) and amplitude-integrated electroencephalography (aEEG) can predict abnormal brain MRI in neonatal HIE.

METHODS

WTC analysis was performed between dynamic oscillations of simultaneously recorded aEEG and cerebral tissue oxygen saturation (SctO2) signals for the first 24 h after birth. The squared cross-wavelet coherence, R2, of the time-frequency domain described by the WTC, is a localized correlation coefficient (ranging between 0 and 1) between these two signals in the time-frequency domain. Statistical analysis was based on Monte Carlo simulation with a 95% confidence interval to identify the time-frequency areas from the WTC scalograms. Brain MRI was performed on all neonates and classified as normal or abnormal based on an accepted classification system for HIE. Wavelet metrics of % significant SctO2-aEEG coherence was compared between the normal and abnormal MRI groups.

RESULT

This prospective study recruited a total of 36 neonates with HIE. A total of 10 had an abnormal brain MRI while 26 had normal MRI. The analysis showed that the SctO2-aEEG coherence between the group with normal and abnormal MRI were significantly different (p = 0.0007) in a very low-frequency (VLF) range of 0.06-0.2 mHz. Using receiver operating characteristic (ROC) curves, the use of WTC-analysis of NVC had an area under the curve (AUC) of 0.808, and with a cutoff of 10% NVC. Sensitivity was 69%, specificity was 90%, positive predictive value (PPV) was 94%, and negative predictive value (NPV) was 52% for predicting brain injury on MRI. This was superior to the clinical Total Sarnat score (TSS) where AUC was 0.442 with sensitivity 61.5%, specificity 30%, PPV 75%, and NPV 31%.

CONCLUSION

NVC is a promising neurophysiological biomarker in neonates with HIE, and in our prospective cohort was superior to the clinical Total Sarnat score for prediction of abnormal brain MRI.

Mild Hypoxic-Ischemic Encephalopathy: Can Neurophysiological Monitoring Predict Unfavorable Neurological Outcome? A Systematic Review and Meta-analysis

OBJECTIVE

 Hypoxic-ischemic encephalopathy (HIE) is the second cause of neonatal deaths and one of the main conditions responsible for long-term neurological disability. Contrary to past belief, children with mild HIE can also experience long-term neurological sequelae. The aim of this systematic review is to determine the predictive value of long-term neurological outcome of (electroencephalogram) EEG/amplitude-integrated electroencephalogram (aEEG) in children who complained mild HIE.

STUDY DESIGN

 From a first search on PubMed, Google Scholar, and clinicalTrials.gov databases, only five articles were considered suitable for this study review. A statistical meta-analysis with the evaluation of odds ratio was performed on three of these studies.

RESULTS

 No correlation was found between the characteristics of the electrical activity of the brain obtained through EEG/aEEG in infants with mild HIE and subsequent neurological involvement.

CONCLUSION

 EEG/aEEG monitoring in infants with mild HIE cannot be considered a useful tool in predicting their neurodevelopmental outcome, and its use for this purpose is reported as barely reliable.

KEY POINTS

· Hypoxic-Ischemic Encephalopathy is responsible for long-term neurological outcome, even in newborns with mild HIE.. · No correlation was found between EEG/aEEG trace in infants with mild HIE and neurological sequelae.. · Neurophysiological monitoring, in mild HIE, cannot predic neurodevelopmental outcome..

Predictive value of early amplitude integrated electroencephalogram (aEEG) in sleep related problems in children with perinatal hypoxic-ischemia (HIE)

Background

While great attention has been paid to motor and cognitive impairments in children with neonatal Hypoxic-Ischemic Encephalopathy (HIE), sleep related circadian rhythm problems, although commonly present, are often neglected. Subsequently, no early clinical indicators have been reported to correlate with sleep-related circadian dysfunction during development.

Methods

In this study, we first analyzed patterns of the amplitude integrated electroencephalogram (aEEG) in a cohort of newborns with various degrees of HIE. Next, during follow-ups, we collected information of sleep and circadian related problems in these patients and performed correlation analysis between aEEG parameters and different sleep/circadian disorders.

Results

A total of 101 neonates were included. Our results demonstrated that abnormal aEEG background pattern is significantly correlated with circadian rhythmic (r = 0.289, P = 0.01) and breathing issues during sleep (r = 0.237, P = 0.037). In contrast, the establishment of sleep–wake cycle (SWC) showed no correlation with sleep/circadian problems. Detailed analysis showed that summation of aEEG score, along with low base voltage (r = 0.272, P = 0.017 and r = -0.228, P = 0.048, respectively), correlates with sleep circadian problems. In contrast, background pattern (BP) score highly correlates with sleep breathing problem (r = 0.319, P = 0.004).

Conclusion

Abnormal neonatal aEEG pattern is correlated with circadian related sleep problems. Our study thus provides novel insights into predictive values of aEEG in sleep-related circadian problems in children with HIE.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-021-02796-9.

Novel Point-of-Care Diagnostic Method for Neonatal Encephalopathy Using Purine Nucleosides

Background: Evidence suggests that earlier diagnosis and initiation of treatment immediately after birth is critical for improved neurodevelopmental outcomes following neonatal encephalopathy (NE). Current diagnostic tests are, however, mainly restricted to clinical diagnosis with no molecular tests available. Purines including adenosine are released during brain injury such as hypoxia and are also present in biofluids. Whether blood purine changes can be used to diagnose NE has not been investigated to date. Methods: Blood purines were measured in a mouse model of neonatal hypoxia and infants with NE using a novel point-of-care diagnostic technology (SMARTChip) based on the summated electrochemical detection of adenosine and adenosine metabolites in the blood. Results: Blood purine concentrations were ∼2-3-fold elevated following hypoxia in mice [2.77 ± 0.48 μM (Control) vs. 7.57 ± 1.41 μM (post-hypoxia), p = 0.029]. Data in infants with NE had a 2-3-fold elevation when compared to healthy controls [1.63 ± 0.47 μM (Control, N = 5) vs. 4.87 ± 0.92 μM (NE, N = 21), p = 0.0155]. ROC curve analysis demonstrates a high sensitivity (81%) and specificity (80%) for our approach to identify infants with NE. Moreover, blood purine concentrations were higher in infants with NE and seizures [8.13 ± 3.23 μM (with seizures, N = 5) vs. 3.86 ± 0.56 μM (without seizures, N = 16), p = 0.044]. Conclusion: Our data provides the proof-of-concept that measurement of blood purine concentrations via SMARTChip technology may offer a low-volume bedside test to support a rapid diagnosis of NE.

Changing clinical characteristics of infants treated for hypoxic-ischaemic encephalopathy in England, Wales and Scotland: a population-based study using the National Neonatal Research Database

BACKGROUND

Therapeutic hypothermia is standard of care for babies with moderate/severe hypoxic-ischaemic encephalopathy and is increasingly used for mild encephalopathy.

OBJECTIVE

Describe temporal trends in the clinical condition of babies diagnosed with hypoxic-ischaemic encephalopathy who received therapeutic hypothermia.

DESIGN

Retrospective cohort study using data held in the National Neonatal Research Database.

SETTING

National Health Service neonatal units in England, Wales and Scotland.

PATIENTS

Infants born from 1 January 2010 to 31 December 2017 with a recorded diagnosis of hypoxic-ischaemic encephalopathy who received therapeutic hypothermia for at least 3 days or died in this period.

MAIN OUTCOMES

Primary outcomes: recorded clinical characteristics including umbilical cord pH; Apgar score; newborn resuscitation; seizures and treatment on day 1.

SECONDARY OUTCOMES

recorded hypoxic-ischaemic encephalopathy grade.

RESULTS

5201 babies with a diagnosis of hypoxic-ischaemic encephalopathy received therapeutic hypothermia or died; annual numbers increased over the study period. A decreasing proportion had clinical characteristics of severe hypoxia ischaemia or a diagnosis of moderate or severe hypoxic-ischaemic encephalopathy, trends were statistically significant and consistent across multiple clinical characteristics used as markers of severity.

CONCLUSIONS

Treatment with therapeutic hypothermia for hypoxic-ischaemic encephalopathy has increased in England, Scotland and Wales. An increasing proportion of treated infants have a diagnosis of mild hypoxic-ischaemic encephalopathy or have less severe clinical markers of hypoxia. This highlights the importance of determining the role of hypothermia in mild hypoxic-ischaemic encephalopathy. Receipt of therapeutic hypothermia is unlikely to be a useful marker for assessing changes in the incidence of brain injury over time.

Trends in the incidence and management of hypoxic-ischaemic encephalopathy in the therapeutic hypothermia era: a national population study

OBJECTIVE

Hypoxic-ischaemic encephalopathy (HIE) remains a leading cause of neonatal mortality and neurodisability. We aimed to determine the incidence of HIE and management patterns against national guidelines.

DESIGN

Retrospective cohort study using the National Neonatal Research Database.

SETTING

Neonatal units in England and Wales.

PATIENTS

Infants 34-42 weeks gestational age (GA) with a recorded diagnosis of HIE.

MAIN OUTCOMES

Incidence of HIE, mortality and treatment with therapeutic hypothermia (TH) were the main outcomes. Temporal changes were compared across two epochs (2011-2013 and 2014-2016).

RESULTS

Among 407 462 infants admitted for neonatal care, 12 195 were diagnosed with HIE. 8166 infants ≥36 weeks GA had moderate/severe HIE, 62.1% (n=5069) underwent TH and mortality was 9.3% (n=762). Of infants with mild HIE (n=3394), 30.3% (n=1027) underwent TH and 6 died. In late preterm infants (34-35 weeks GA) with HIE (n=635, 5.2%), 33.1% (n=210) received TH and 13.1% (n=83) died. Between epochs (2011-2013 vs 2014-2016), mortality decreased for infants ≥36 weeks GA with moderate/severe HIE (17.5% vs 12.3%; OR 0.69, 95% CI 0.59 to 0.81, p<0.001). Treatment with TH increased significantly between epochs in infants with mild HIE (24.9% vs 35.8%, p<0.001) and those born late preterm (34.3% vs 46.6%, p=0.002).

CONCLUSIONS

Mortality of infants ≥36 weeks GA with moderate/severe HIE has reduced over time, although many infants diagnosed with moderate/severe HIE do not undergo TH. Increasingly, mild HIE and late preterm infants with HIE are undergoing TH, where the evidence base is lacking, highlighting the need for prospective studies to evaluate safety and efficacy in these populations.

EEG Spectral Power: A Proposed Physiological Biomarker to Classify the Hypoxic-Ischemic Encephalopathy Severity in Real Time

BACKGROUND

Mild hypoxic-ischemic encephalopathy (HIE) constitutes a large unstudied population with considerable debate on how to define and treat due to the dynamic evolution of the clinical signs of encephalopathy. We propose to address this gap with quantitative physiological biomarkers to aid in stratification of the disease severity. The objectives of this prospective cohort study were to measure the electroencephalographic (EEG) power as an objective biomarker of the evolution of the clinical encephalopathy in newborns with mild to severe HIE.

METHODS

EEG was collected in infants with HIE using four bipolar electrodes analyzed for the first three hours of the recording. Delta power (DP, 0.5 to 4 Hz) and total power (TP, 0.5 to 20 Hz) were compared between groups with different HIE severity using a univariate ordinal logistic regression model and receiver operating characteristic curves.

RESULTS

A total of 44 term-born infants with mild to severe HIE were identified within six hours of birth. The DP and TP values were significantly higher for the mild group than for the moderate group for all bipolar electrodes. A one-unit increase in DP was associated with significantly lower odds of encephalopathy. DP best distinguished mild from higher encephalopathy grades by area under the curve.

CONCLUSIONS

We conclude that DP and TP are sensitive real-time biomarkers for monitoring the dynamic evolution of the encephalopathy severity in the first day of life. The quantitative EEG power may lead to timely recognition of the worsening of the encephalopathy and guide future therapeutic interventions targeting mild HIE.

Cooling in mild encephalopathy: Costs and perils of therapeutic creep

Increasing confidence in therapeutic hypothermia and ambiguity of cooling guidelines has led to many clinicians extending its use to untested populations like mild encephalopathy, or even no encephalopathy. Poor quality clinical neurological examination for encephalopathy staging coupled with a fear of litigation if a baby with mild encephalopathy progress to moderate or severe encephalopathy appears to be the primary driver for this therapeutic creep. Recent data suggesting increased apoptosis with cooling uninjured brains, and lack of hypothermic neuroprotection in partial prolonged hypoxia, implies that such therapeutic creeps may cause more harm than benefit. Currently available preclinical and clinical data do not support the clinical use of therapeutic hypothermia for mild encephalopathy, although phase II clinical trials are ongoing. We recommend that until further evidence from adequately powered randomised controlled trials are available, cooling in mild encephalopathy need to be considered experimental and parental consent should be obtained before providing this therapy.

Darbepoetin as a neuroprotective agent in mild neonatal encephalopathy: a randomized, placebo-controlled, feasibility trial

OBJECTIVE

To assess the feasibility and safety of one dose of Darbepoetin alpha (Darbe) administered to neonates ≥34 weeks with mild neonatal encephalopathy (NE).

METHODS

Randomized, masked, placebo-controlled study including neonates ≥34 weeks gestation with mild NE. Neonates were randomized to receive one dose of Darbe (10 μg/kg IV) or placebo. Clinical and laboratory maternal and newborn data were collected. The Bayley Scales of Infant and Toddler Development, third edition (Bayley-III) and a standardized neurological examination at 8-12 months of corrected age were assessed.

RESULTS

There were no differences in baseline characteristics of the 21 infants randomized (9 Darbe, 12 placebo). Adverse events were not reported at any time. Bayley-III scores were average in both Darbe and placebo groups.

CONCLUSION

This study demonstrates that a randomized, masked, placebo-controlled trial is safe and feasible. A large, randomized trial is warranted to assess the effect of Darbe in this population.

Efficacy of different treatment times of mild cerebral hypothermia on oxidative factors and neuroprotective effects in neonatal patients with moderate/severe hypoxic-ischemic encephalopathy

Objective

To investigate the efficacy of different treatment times of mild cerebral hypothermia for treating moderate/severe hypoxic–ischemic encephalopathy (HIE) in neonatal patients and its effects on oxidative factors.

Methods

This prospective, randomized, controlled study included 92 neonatal patients with moderate/severe HIE and 30 controls. The patients with HIE received routine treatment, 48 hours of hypothermia, or 72 hours of hypothermia.

Results

Superoxide dismutase (SOD) values were significantly lower and malondialdehyde (MDA) and neuron-specific enolase (NSE) values were higher in patients with HIE than in controls before the study. After 24, 48, and 72 hours of treatment, SOD values in all patients with HIE gradually increased and MDA and NSE values gradually decreased. At 3, 7, and 10 days, the Neonatal Behavioral Neurological Assessment scores were highest in the mild hypothermia for 72 hours group than in the other groups. The Mental and Psychomotor Development Indices scores of the Bayley Scales were significantly higher in the mild hypothermia for 72 hours group than in the other groups.

Conclusion

Hypothermia treatment of 72 hours is better than 48 hours for improving oxidative conditions, reducing NSE values, and improving neurological behavior and development for neonates with moderate/severe HIE.