Short and long term prognosis in perinatal asphyxia: An update

Torn between two worlds: parental experiences of neonatal follow-up for infants with hypoxic ischaemic encephalopathy in India-a qualitative study using interpretative phenomenological analysis

OBJECTIVE

This study aimed to understand the barriers and facilitators of a neonatal follow-up programme, as perceived by parents of infants born with hypoxic ischaemic encephalopathy (HIE).

DESIGN

This study applied a qualitative study design using interpretative phenomenological analysis. It included focus group discussions, face-to-face in-depth interviews and telephonic interviews. Data were analysed using thematic content analysis.

SETTING

Neonatal follow-up clinic of a tertiary hospital in South India. The study was conducted between March and December 2020.

PARTICIPANTS

Five fathers and eight mothers of infants with HIE.

RESULTS

Parents of children with HIE are torn between two worlds-an atmosphere of support and one of criticism. Three main themes were identified: (1) neonatal intensive care unit (NICU) stay: distressful versus reassuring experiences; (2) parenthood: supportive versus unsupportive environments; and (3) neonatal follow-up: adherence versus non-adherence.

CONCLUSION

Parents of children with HIE experience sociocultural barriers in the NICU, after discharge and during the follow-up period. These lead to a complex array of emotional and physical consequences that affect parenting and follow-up care.

Hypoxia Depresses Synaptic Transmission in the Primary Motor Cortex of the Infant Rat-Role of Adenosine A1 Receptors and Nitric Oxide

The acute and long-term consequences of perinatal asphyxia have been extensively investigated, but only a few studies have focused on postnatal asphyxia. In particular, electrophysiological changes induced in the motor cortex by postnatal asphyxia have not been examined so far, despite the critical involvement of this cortical area in epilepsy. In this study, we exposed primary motor cortex slices obtained from infant rats in an age window (16-18 day-old) characterized by high incidence of hypoxia-induced seizures associated with epileptiform motor behavior to 10 min of hypoxia. Extracellular field potentials evoked by horizontal pathway stimulation were recorded in layers II/III of the primary motor cortex before, during, and after the hypoxic event. The results show that hypoxia reversibly depressed glutamatergic synaptic transmission and neuronal excitability. Data obtained in the presence of specific blockers suggest that synaptic depression was mediated by adenosine acting on pre-synaptic A1 receptors to decrease glutamate release, and by a nitric oxide (NO)/cGMP postsynaptic pathway. These effects are neuroprotective because they limit energy failure. The present findings may be helpful in the preclinical search for therapeutic strategies aimed at preventing acute and long-term neurological consequences of postnatal asphyxia.

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.

Parent concerns for child development following admission to neonatal intensive or special care: From birth to adolescence

AIM

To describe the presence and nature of parent concerns regarding the development of their children admitted to Australian neonatal units (NNUs), comprising neonatal intensive care or special care.

METHODS

In a cross-sectional survey, mothers and fathers provided information regarding concerns for their child's development. The self-administered survey was completed by two separate cohorts; (i) parents of child graduates from Australian NNUs (n = 381); (ii) parents of infant's inpatient in two South Australian NNUs (n = 209). Data were analysed using thematic analysis and descriptive statistics.

RESULTS

Information was provided for 730 children. Developmental concern was reported for 39% of NNU graduates and 35% of inpatients. Children born very preterm (< 32 weeks' gestation) elicited greater parent concern than those born more mature (Cohort 1: 41% vs 36%; Cohort 2: 49% vs 22%), including in multiple developmental domains (Cohort 1: 17% vs 15%; Cohort 2: 28% vs 4%). Parents with inpatient infants were predominantly concerned about general development-milestones (19.1%) and the potential impact of medical or CNS issues (13.7%). Graduate parents commonly focused on specific domains, such as their child's speech-language (13.7%) and motor (12.9%) development.

CONCLUSION

Neurodevelopment is a substantial source of concern for mothers and fathers during NNU admission and childhood, particularly for children born very preterm. However, in the first year of life, developmental concerns are poorly defined. This highlights the need for clinical education resources detailing infant developmental expectations and supportive strategies for parents of these high-risk infants.

Neuroprotective and Regenerative Effects of Growth Hormone (GH) in the Embryonic Chicken Cerebral Pallium Exposed to Hypoxic-Ischemic (HI) Injury

Prenatal hypoxic−ischemic (HI) injury inflicts severe damage on the developing brain provoked by a pathophysiological response that leads to neural structural lesions, synaptic loss, and neuronal death, which may result in a high risk of permanent neurological deficits or even newborn decease. It is known that growth hormone (GH) can act as a neurotrophic factor inducing neuroprotection, neurite growth, and synaptogenesis after HI injury. In this study we used the chicken embryo to develop both in vitro and in vivo models of prenatal HI injury in the cerebral pallium, which is the equivalent of brain cortex in mammals, to examine whether GH exerts neuroprotective and regenerative effects in this tissue and the putative mechanisms involved in these actions. For the in vitro experiments, pallial cell cultures obtained from chick embryos were incubated under HI conditions (<5% O2, 1 g/L glucose) for 24 h and treated with 10 nM GH, and then collected for analysis. For the in vivo experiments, chicken embryos (ED14) were injected in ovo with GH (2.25 µg), exposed to hypoxia (12% O2) for 6 h, and later the pallial tissue was obtained to perform the studies. Results show that GH exerted a clear anti-apoptotic effect and promoted cell survival and proliferation in HI-injured pallial neurons, in both in vitro and in vivo models. Neuroprotective actions of GH were associated with the activation of ERK1/2 and Bcl-2 signaling pathways. Remarkably, GH protected mature neurons that were particularly harmed by HI injury, but was also capable of stimulating neural precursors. In addition, GH stimulated restorative processes such as the number and length of neurite outgrowth and branching in HI-injured pallial neurons, and these effects were blocked by a specific GH antibody, thus indicating a direct action of GH. Furthermore, it was found that the local expression of several synaptogenic markers (NRXN1, NRXN3, GAP-43, and NLG1) and neurotrophic factors (GH, BDNF, NT-3, IGF-1, and BMP4) were increased after GH treatment during HI damage. Together, these results provide novel evidence supporting that GH exerts protective and restorative effects in brain pallium during prenatal HI injury, and these actions could be the result of a joint effect between GH and endogenous neurotrophic factors. Also, they encourage further research on the potential role of GH as a therapeutic complement in HI encephalopathy treatments.

Group II Metabotropic Glutamate Receptors Reduce Apoptosis and Regulate BDNF and GDNF Levels in Hypoxic-Ischemic Injury in Neonatal Rats

Birth asphyxia causes brain injury in neonates, but a fully successful treatment has yet to be developed. This study aimed to investigate the effect of group II mGlu receptors activation after experimental birth asphyxia (hypoxia-ischemia) on the expression of factors involved in apoptosis and neuroprotective neurotrophins. Hypoxia-ischemia (HI) on 7-day-old rats was used as an experimental model. The effects of intraperitoneal application of mGluR2 agonist LY379268 (5 mg/kg) and the specific mGluR3 agonist NAAG (5 mg/kg) (1 h or 6 h after HI) on apoptotic processes and initiation of the neuroprotective mechanism were investigated. LY379268 and NAAG applied shortly after HI prevented brain damage and significantly decreased pro-apoptotic Bax and HtrA2/Omi expression, increasing expression of anti-apoptotic Bcl-2. NAAG or LY379268 applied at both times also decreased HIF-1α formation. HI caused a significant decrease in BDNF concentration, which was restored after LY379268 or NAAG administration. HI-induced increase in GDNF concentration was decreased after administration of LY379268 or NAAG. Our results show that activation of mGluR2/3 receptors shortly after HI prevents brain damage by the inhibition of excessive glutamate release and apoptotic damage decrease. mGluR2 and mGluR3 agonists produced comparable results, indicating that both receptors may be a potential target for early treatment in neonatal HI.

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.

Defining longer term outcomes in an ovine model of moderate perinatal hypoxia-ischemia

Hypoxic-ischemic encephalopathy (HIE) is the leading cause of neonatal morbidity and mortality worldwide. Approximately 1 million infants born with HIE each year survive with cerebral palsy (CP) and/or serious cognitive disabilities. While infants born with mild and severe HIE frequently result in predictable outcomes, infants born with moderate HIE exhibit variable outcomes that are highly unpredictable. Here, we describe an umbilical cord occlusion (UCO) model of moderate HIE with a 6-day follow-up. Near term lambs (n=27) are resuscitated after the induction of 5 minutes of asystole. Following recovery, lambs are assessed to define neurodevelopmental outcomes. At the end of this period, lambs are euthanized, and brains harvested for histological analysis. Compared with prior models that typically follow lambs for 3 days, the observation of neurobehavioral outcomes for 6 days enables identification of animals that recover significant neurological function. Approximately 35 % of lambs exhibited severe motor deficits throughout the entirety of the 6-day course and, in the most severely affected lambs, developed spastic diparesis similar to that observed in infants who survive severe neonatal HIE (severe, UCOs). Importantly, and similar to outcomes in human neonates, while initially developing significant acidosis and encephalopathy, the remainder of the lambs in this model recovered normal motor activity and exhibited normal neurodevelopmental outcomes by 6 days of life (improved, UCOi). The UCOs group exhibited gliosis and inflammation in both white and gray matter, oligodendrocyte loss, and neuronal loss and cellular death in the hippocampus and cingulate cortex. While the UCOi group exhibited more cellular death and gliosis in the parasagittal cortex and demonstrated more preserved white matter markers, along with reduced markers of inflammation and lower cellular death and neuronal loss in Ca3 of the hippocampus compared with UCOs lambs. Our large animal model of moderate HIE with prolonged follow-up will help further define pathophysiologic drivers of brain injury while enabling identification of predictive biomarkers that correlate with disease outcomes and ultimately help support development of therapeutic approaches to this challenging clinical scenario.

Survival and predictors of asphyxia among neonates admitted in neonatal intensive care units of public hospitals of Addis Ababa, Ethiopia, 2021: a retrospective follow-up study

BACKGROUND

Globally, perinatal asphyxia (PNA) is a significant cause of most neonatal deaths. Similarly, the burden of birth asphyxia in Ethiopia remains high (22.52%) and has been noted the second leading cause of neonatal mortality. Thus, researches on survival status and predictors of perinatal asphyxia are critical to tackle it. Therefore, the current study intended to determine the survival status and predictors of asphyxia among neonates admitted in Neonatal Intensive Care Units of public hospitals, Addis Ababa, Ethiopia.

METHODS

Hospital-based retrospective follow-up study was conducted in four selected public hospitals of Addis Ababa from January 2016 to December 2020. Data were collected using a pretested structured questionnaire. Epi-data 4.6 and STATA Version 16 was used for data entry and analysis, respectively. Kaplan-Meier survival curve, log-rank test and Median time were computed. To find the predictors of time to recovery, a multivariable Cox proportional hazards regression model was fitted, and variables with a P-value less than 0.05 were considered statistically significant. Finally, the Schoenfeld residual test was used to check overall model fitness.

RESULT

Four hundred eleven admitted asphyxiated babies were followed a total of 3062 neonate-days with a minimum of 1 h to a maximum of 28 days. The Overall incidence density rate of survival was 10 (95% CI: 0.08-0.11) per 100 neonate-days of observation with a median recovery time of 8 days (95% CI: 7.527-8.473). Low birth weight (Adjusted hazard ratio [AHR]: 0.67, 95% CI: 0.47-0.96), stage II hypoxic ischemic encephalopathy (HIE) (AHR: 0.70, 95% CI: 0.51-0.97), stage III HIE (AHR: 0.44, 95% CI: 0.27-0.71), seizure (AHR: 0.61, 95% CI: 0.38-0.97), thrombocytopenia (AHR: 0.44, 95% CI: 0.24-0.80) and calcium gluconate (AHR: 0.75, 95% CI: 0.58-0.99) were found to be independent predictors of time to recovery of asphyxiated neonates.

CONCLUSION

In the current findings, the recovery time was prolonged compared to others finding. This implies early prevention, strict monitoring and taking appropriate measures timely is mandatory before babies transferred into highest stage of HIE and managing complications are recommended to hasten recovery time and increase survival of neonates.

Risk Factors of Birth Asphyxia among Newborns at Debre Markos Comprehensive Specialized Referral Hospital, Northwest Ethiopia: Unmatched Case-Control Study

Background

Despite a global decline in under-five deaths, the neonatal mortality rate remains slow in developing countries and birth asphyxia remains the third cause of neonatal deaths. Globally, neonatal deaths accounts for 45% of under-five deaths, birth asphyxia causes 23-40% of neonatal deaths in Ethiopia. There is limited data on risk factors of asphyxia in Ethiopia, particularly in the study area. Therefore, this study aimed to identify the risk factors of birth asphyxia among newborns.

Methods

This research followed a hospital-based unmatched case-control study design at Debre Markos comprehensive specialized referral hospital, Northwest Ethiopia, among 372 newborns (124 cases and 248 controls). Data were collected by interviewing index mothers and chart review using a pre-tested questionnaire. Then it was entered in Epi-data version 3.1 and transferred to STATA version 14.0 for analysis. Bivariate and multiple variable logistic regression were carried out to the possible risk factors. Finally, statistical significance was declared using adjusted odds ratio with 95% CI and p-value <0.05.

Results

Prolonged labor >12, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, noncephalic presentation, comorbidity, birthweight<2500grams were found to be significant factors of birth asphyxia.

Conclusion

In this study, Prolonged labor >12 hours, meconium-stained amniotic fluid, assisted vaginal delivery, gestational age < 37 weeks, non-cephalic presentation comorbidity, fetal distress, birthweight<2500grams were found to be risk factors of birth asphyxia were risk factors of birth asphyxia. Therefore, to reduce neonatal mortality associated with birth asphyxia, attention should be given to holistic pregnancy, labor and delivery care, and post-natal care. Moreover, interventions aimed at reducing birth asphyxia should target the identified factors.

Hypoxic Ischemic Encephalopathy (HIE) in Term and Preterm Infants

Hypoxic-ischemic syndrome (HIS) and Hypoxic-ischemic encephalopathy (HIE) are conditions that affect term and premature babies, with different pathophysiology and different brain disorders. HIE appears in 1-6 / 1000 live births and 26/1000 live births in developing countries. 15-20% die in the early neonatal period, while surviving babies have severe neurological impairment, including cerebral palsy, epilepsy, visual and hearing impairment, cognitive impairment, intellectual, behavioural, and social disorders. The hypoxic-ischemic event occurs before, during or after birth. The reasons may be related to the mother, the way of birth, the placenta, and the newborn. The criteria for diagnosis of HIE include a combination of perinatal factors, the need for resuscitation, standard neurological examinations, neurophysiological monitoring, neuroimaging methods and biochemical markers. The most effective treatment for HIE is hypothermia in combination with pharmacological therapy. HIE and HIS are problem that still persist in developing countries due to inadequate obstetric care, neonatal resuscitation, and hypothermia. Current and emerging research for HIE examines new markers for early recognition, treatment, and appropriate neuroprotection of high-risk term and premature infants.

Prognostic Value of Various Diagnostic Methods for Long-Term Outcome of Newborns After Hypoxic-Ischemic Encephalopathy Treated With Hypothermia

INTRODUCTION

Prediction of outcome in newborns with hypoxic-ischemic encephalopathy (HIE) has been modulated by hypothermia treatment (HT). We assessed the predictive value of diagnostic methods commonly used in neonates with HIE for short-term neurodevelopmental outcome and long-term neurological outcome.

MATERIALS AND METHODS

This longitudinal cohort study followed up 50 term newborns who underwent HT after HIE between July 2006 and August 2015, until preschool age. We estimated sensitivity and specificity for short-term neurodevelopmental outcome at 18 months and long-term neurological outcome at five years based on Amiel-Tison Neurological Assessment (ATNA), electroencephalography (EEG), and magnetic resonance imaging (MRI) performed in the neonatal period.

RESULTS

The accuracy of all neonatal methods tested was higher for long-term neurological outcome compared to the predictive accuracy for short-term neurodevelopmental outcome at 18-24 months. Sensitivity and specificity in predicting unfavorable long-term neurological outcome were: MRI (sensitivity 1.0 [95%CI 0.96-1.0]; specificity 0.91 [95%CI 0.86-1.0]), EEG (sensitivity 0.94 [95%CI 0.71-1.0]; specificity 1.0 [95% CI 0.89-1.0]), and ATNA (sensitivity 0.94 [95%CI 0.71-1.0]; specificity 0.91 [95%CI 0.76-0.98]).

CONCLUSION

MRI is a powerful predictor of long-term neurological outcome when performed in the first week after HIE in HT treated infants, as are EEG and ATNA performed in the second or third week postnatally.

COVID 19 in pregnant women and neonates: Clinical characteristics and laboratory and imaging findings. An overview of systematic reviews

Introduction: SARS-CoV-2 infection in the perinatal period may be associated with an increased risk of morbidity and mortality in both the mother and the neonate. Objective: To describe the clinical characteristics and, laboratory and imaging findings in pregnant women with COVID-19 and their newborns. Materials and methods: We searched PubMed, Scopus, Web of Science, and Cochrane databases for systematic reviews published between February 1, 2020, and May 30, 2021, describing clinical characteristics and laboratory and imaging (chest) findings in pregnant women with COVID-19 and their newborns; there were no language restrictions. Data were reanalyzed by means of Bayesian meta-analysis using Markov Chain Monte Carlo methods. The study protocol is registered in PROSPERO under code CRD42020178329. Results: Six systematic reviews were retrieved (for a total of 617 primary studies). A narrative synthesis of the proportions of signs, symptoms, and imaging and laboratory findings of both mothers and neonates was performed. The Odds ratios (OR) between pregnant women with and without COVID-19 were as follows: fetal well-being involvement: 1.9 (95%CI:1.09-3.63); stillbirth: 1.73 (95%CI:1.01-2.94); preterm birth: 1.77 (95%CI:1.25-2.61); maternal admission to the intensive care unit (ICU): 6.75 (95%CI:1-31.19). Regarding symptomatology, the following OR was obtained for myalgia between pregnant women and non-pregnant women with COVID-19: 0.67 (95% CI:0.51-0.93). Conclusions: Cough, fever, dyspnea, and myalgia are the most common symptoms in pregnant women with COVID-19; in addition, there is a higher risk of admission to the ICU. Regarding complementary testing, the most frequent alterations are lymphopenia and the evidence of lesions in chest imaging studies. The presence of COVID-19 in pregnant women is associated with premature birth. It seems that SARS-CoV-2 infection in neonates is not serious and the risk of vertical transmission is low, since no data about congenital malformations attributable to the virus were found.

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.

Magnetic Resonance Imaging in (Near-)Term Infants with Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a major cause of neurological sequelae in (near-)term newborns. Despite the use of therapeutic hypothermia, a significant number of newborns still experience impaired neurodevelopment. Neuroimaging is the standard of care in infants with HIE to determine the timing and nature of the injury, guide further treatment decisions, and predict neurodevelopmental outcomes. Cranial ultrasonography is a helpful noninvasive tool to assess the brain before initiation of hypothermia to look for abnormalities suggestive of HIE mimics or antenatal onset of injury. Magnetic resonance imaging (MRI) which includes diffusion-weighted imaging has, however, become the gold standard to assess brain injury in infants with HIE, and has an excellent prognostic utility. Magnetic resonance spectroscopy provides complementary metabolic information and has also been shown to be a reliable prognostic biomarker. Advanced imaging modalities, including diffusion tensor imaging and arterial spin labeling, are increasingly being used to gain further information about the etiology and prognosis of brain injury. Over the past decades, tremendous progress has been made in the field of neonatal neuroimaging. In this review, the main brain injury patterns of infants with HIE, the application of conventional and advanced MRI techniques in these newborns, and HIE mimics, will be described.

Prognostic neurobiomarkers in neonatal encephalopathy

Therapeutic hypothermia is now standard-care for infants with moderate-severe neonatal encephalopathy (NE), and improves brain damage on neuroimaging, and neurodevelopmental outcomes. Critically, for effective neuroprotection, hypothermia should be started within 6 h from birth. There is compelling evidence to suggest that a proportion of infants with mild NE have material risk of developing brain damage and poor outcomes. This cohort is increasingly being offered therapeutic hypothermia, despite lack of trial evidence for its benefit. In current practice, infants need to be diagnosed within 6 h of birth for therapeutic treatment, compared to retrospective NE grading in the pre-hypothermia era. This presents challenges as NE is a dynamic brain disorder that can worsen or resolve over time. Neurological symptoms of NE can be difficult to discern in the first few hours after birth, and confounded by analgesics and anesthetic treatment. Using current enrolment criteria, a significant number of infants with NE that would benefit from hypothermia are not treated, and vice versa, infants are receiving mild hypothermia when its benefit will be limited. Better biomarkers are needed to further improve management and treatment of these neonates. In the present review, we examine the latest research, and highlight a central limitation of most current biomarkers: that their predictive value is consistently greatest after most neuroprotective therapies are no longer effective.

EPO activates PI3K-IKKα-CDK1 signaling pathway to promote the proliferation of Glial Cells under hypoxia environment

Erythropoietin (EPO), supports the function and survival of neurons through astrocytes and has a protective role in neonatal asphyxia brain injury; yet, its mechanism of action remains unclear. As a neuroprotective factor, EPO is also used in the treatment of various diseases, such as neurodegenerative diseases, Parkinson's disease, traumatic brain injury, by decreasing inflammatory reaction, resisting apoptosis, and lowering oxidative stress. The aim of this study was to examine the effect and mechanism of EPO on promoting human brain glial cell proliferation under hypoxia in vitro. Under CoC12-induced hypoxia, after adding EPO, high-throughput sequencing was used to screen out meaningful up-regulated and significant differentially expressed genes PI3K, IKKα CDK1 related to proliferation, and make further verification by qPCR and western blotting. Under hypoxia, EPO promoted cell proliferation and the expression of PI3K while this effect was inhibited (along with a decrease of downstream genes IKKα and CDK1 decreased) after adding PI3K inhibitor to cell culture. EPO can promote cell proliferation and CDK1 expression, while after inhibiting CDK1 expression, the promotion of EPO on cell proliferation was eliminated. These data proved that EPO promotes the proliferation of U251 cells by activating the PI3K-IKKα-CDK1 signaling pathway under CoC12-induced hypoxia.

Magnetic Resonance Imaging Evaluation of Perinatal Hypoxic Ischemic Encephalopathy: An Institutional Experience

Background Hypoxic–ischemic encephalopathy (HIE) is the most commonly diagnosed neurological abnormality affecting children leading to severe neurological deficits and a cause of neonatal mortality. HIE constitutes a diagnostic challenge in the prematurely born and full-term neonates. HIE causes severe neurological deficit in children and many a times goes unnoticed in early stages. The various patterns of central nervous system (CNS) involvement in HIE are dependent on factors, such as severity and duration of hypoxia, and brain maturity in preterm and full-term patients. Magnetic resonance imaging (MRI) has prognostic significance in detecting patterns of HIE secondary to mild-to-moderate and severe hypoxias and the imaging findings are highly dependent on the time at which imaging is done. MRI helps determine the prognosis of brain development in patients with HIE.

Objective This retrospective study elucidates the spectrum of MRI findings in preterm and full-term patients with HIE on MRI.

Materials and Methods This retrospective descriptive study was conducted at a tertiary care center between April 2017 and May 2019 on 50 patients with a clinical diagnosis of HIE using a General Electric (GE) 1.5-Tesla MRI scanner. Various patterns of HIE were evaluated on MRI in preterm and full-term patients.

Results This retrospective study evaluated MRI findings in 50 infants diagnosed with HIE. Eighteen (36%) were preterm and 32 (64%) were full-term patients. Thirty-five (70%) were male and 15 (30%) were female patients. In the current study, developmental delay was the most commonly associated clinical entity in both preterm and full-term patients. In preterm patients, periventricular leukomalacia was the most prevalent MRI finding, and in full-term patients, subcortical and periventricular white matter hyperintensities on T2-weighted and fluid-attenuated inversion recovery (FLAIR) sequences were most commonly encountered.

Conclusion MRI is the primary imaging modality of choice in preterm and full-term patients with HIE, as it helps determine the severity of hypoxic–ischemic injury by understanding the pattern of brain involvement. In the current study, distinguishable patterns of MRI findings secondary to birth asphyxia and ischemic insult were elucidated in both preterm and full-term patients who are highly dependent on the level of brain maturity at the time of imaging. Regular MRI follow-up has a prognostic significance in HIE with accurate prediction of neurodevelopmental outcome on follow-up studies.

Pharmacometric approach to assist dosage regimen design in neonates undergoing therapeutic hypothermia

BACKGROUND

Therapeutic hypothermia (TH) is the treatment of choice for neonates diagnosed with perinatal asphyxia (PA). Dosing recommendations of various therapeutic agents including antimicrobials were not specifically available for the neonates undergoing TH.

METHODS

A systematic search methodology was used to identify pharmacokinetic (PK) studies of antimicrobials during TH. Antimicrobials with multiple PK studies were identified to create a generalizable PK model. Pharmacometric simulations were performed using the PUMAS software platform to reproduce the results of published studies. A suitable model that could reproduce the results of all other published studies was identified. With the help of a generalizable model, an optimal dosage regimen was designed considering the important covariates of the identified model.

RESULTS

With the systematic search, only gentamicin had multiple PK reports during TH. A generalizable model was identified and the model predictions could match the reported/observed concentrations of publications. Birth weight and serum creatinine were the significant covariates influencing the PK of gentamicin in neonates. A dosage nomogram was designed using pharmacometric simulations to maintain gentamicin concentrations below 10 μg/mL at peak and below 2 μg/mL at trough.

CONCLUSIONS

A generalizable PK model for gentamicin during TH in neonates was identified. Using the model, a dosing nomogram for gentamicin was designed.

IMPACT

Dosing guidelines for antimicrobials during TH in neonates is lacking. This is the first study to identify the generalizable model for gentamicin during TH in neonates. Nomogram, proposed in the study, will aid the clinicians to individualize gentamicin dosing regimen for neonates considering the birth weight and serum creatinine.

MicroRNA Expression Profiles as Diagnostic and Prognostic Biomarkers of Perinatal Asphyxia and Hypoxic-Ischaemic Encephalopathy

INTRODUCTION

Perinatal asphyxia is a leading cause of neonatal death. Up to one-third of asphyxiated neonates suffer from hypoxic-ischaemic encephalopathy (HIE) with substantial long-term morbidity. Currently available diagnostic and prognostic tools bear limitations, and additional reliable biomarkers are needed for all stages of clinical management. A novel tool in neuroscientific research is micro-ribonucleic acid (miRNA) profiling. The aim of the present study was to determine miRNA expression profiles of healthy and asphyxiated neonates with and without HIE and to assess their potential as diagnostic and prognostic biomarkers.

METHODS

We prospectively enrolled 49 neonates with a gestational age of ≥36 weeks, 15 of which fulfilled the diagnostic criteria of perinatal asphyxia and 34 served as healthy controls. Dried blood spots were collected from umbilical cord blood (UCB) and from venous blood upon admission to neonatal intensive care unit (NICU) and at 48 h of life. Samples were analysed by means of FirePlex™ technology (Abcam, Cambridge, MA, USA).

RESULTS

In the UCB, miRNA expression levels of hsa-mir-124-3p, hsa-mir-1285-5p, and hsa-mir-331-5p were significantly lower in asphyxiated neonates compared to healthy controls. Asphyxiated neonates requiring therapeutic hypothermia had significantly increased expression of hsa-miR-30e-5p and significantly decreased expression of hsa-miR-142-3p, hsa-miR-338-3p, hsa-miR-34b-3p, hsa-miR-497-5p, and hsa-miR-98-5p at the time of admission to the NICU. At 48 h, infants suffering from moderate/severe HIE with a poor long-term neurodevelopmental outcome showed a significant increase in hsa-mir-145-5p.

DISCUSSION/CONCLUSION

MiRNA profiling shows promise as a biomarker for perinatal asphyxia, hypothermia-requiring HIE, and poor neurodevelopmental outcome. Confirmatory studies are called for.

Sustained Energy Deficit Following Perinatal Asphyxia: A Shift towards the Fructose-2,6-bisphosphatase (TIGAR)-Dependent Pentose Phosphate Pathway and Postnatal Development

Labor and delivery entail a complex and sequential metabolic and physiologic cascade, culminating in most circumstances in successful childbirth, although delivery can be a risky episode if oxygen supply is interrupted, resulting in perinatal asphyxia (PA). PA causes an energy failure, leading to cell dysfunction and death if re-oxygenation is not promptly restored. PA is associated with long-term effects, challenging the ability of the brain to cope with stressors occurring along with life. We review here relevant targets responsible for metabolic cascades linked to neurodevelopmental impairments, that we have identified with a model of global PA in rats. Severe PA induces a sustained effect on redox homeostasis, increasing oxidative stress, decreasing metabolic and tissue antioxidant capacity in vulnerable brain regions, which remains weeks after the insult. Catalase activity is decreased in mesencephalon and hippocampus from PA-exposed (AS), compared to control neonates (CS), in parallel with increased cleaved caspase-3 levels, associated with decreased glutathione reductase and glutathione peroxidase activity, a shift towards the TIGAR-dependent pentose phosphate pathway, and delayed calpain-dependent cell death. The brain damage continues long after the re-oxygenation period, extending for weeks after PA, affecting neurons and glial cells, including myelination in grey and white matter. The resulting vulnerability was investigated with organotypic cultures built from AS and CS rat newborns, showing that substantia nigra TH-dopamine-positive cells from AS were more vulnerable to 1 mM of H2O2 than those from CS animals. Several therapeutic strategies are discussed, including hypothermia; N-acetylcysteine; memantine; nicotinamide, and intranasally administered mesenchymal stem cell secretomes, promising clinical translation.

The use of neuroimaging, Prechtl's general movement assessment and the Hammersmith infant neurological examination in determining the prognosis in 2-year-old infants with hypoxic ischemic encephalopathy who were treated with hypothermia

BACKGROUND

The use of neuroimaging, the General Movement Assessment (GMA), and the Hammersmith Infant Neurological Examination (HINE) to identify the risk of neurodevelopmental delay in early infancy is recommended.

AIM

The aim of this study was to examine the predictive power of neuroimaging, GMA and HINE for neurodevelopmental delay and cerebral palsy (CP) in infants with hypoxic ischemic encephalopathy (HIE) who were treated with hypothermia.

STUDY DESIGN

Retrospective cohort.

SUBJECTS AND OUTCOME MEASURES

This retrospective study included 47 (18 female and 29 male) infants who were treated with hypothermia due to HIE. Neonates with a diagnosis of HIE were followed and assessed using neuroimaging, GMA, HINE and the Bayley Scales of Infant and Toddler Development-II (Bayley II) between 3 m and 2 years of age.

RESULTS

Out of the 47 infants with HIE, no fidgety movements were observed in 5 infants. The sensitivity and specificity in determining the psychomotor developmental index (PDI) score were 97% and 100%, respectively, for MRI; 92.9% and 100% for GMA; and 91.9% and 80% for the HINE. The sensitivity and specificity in determining the mental developmental index (MDI) score were 95% and 85.7%, respectively, for MRI; 90.5% and 80% for GMA; and 91.9% and 50% for HINE. The sensitivity and specificity in determining CP diagnosis at the age of 2 years were 83.3% and 95%, respectively, for MRI; 83.3% and 100% for GMA; and 83.3% and 87.8% for HINE.

CONCLUSION

The interpretation of MRI, GMA, and HINE that are performed within the early period of life may be the gold standard for the early detection of neurodevelopmental risks in 2-year-old infants with HIE. Clinical implementation of these methods in the early period in the follow-up of these infants offers useful information for the early identification of neurodevelopmental risk and for planning early intervention.

Neuroprotective strategies of cerebrolysin for the treatment of infants with neonatal hypoxic-ischemic encephalopathy

BACKGROUND

Perinatal asphyxia (PA) is a devastating neonatal condition characterized by a lack of oxygen supporting the organ systems. PA can lead to hypoxic-ischemic encephalopathy (HIE), a brain dysfunction due to oxygen deprivation with a complex neurological sequela. The pathophysiology of HIE and PA is not entirely understood, with therapeutic hypothermia being the standard treatment with only limited value. However, alternative neuroprotective therapies can be a potential treatment modality.

METHODS

In this review, we will characterize the biochemical mechanisms of PA and HIE, while also giving insight into cerebrolysin, a neuroprotective treatment used for HIE and PA.

RESULTS

We found that cerebrolysin has up to 6-month treatment window post-ischemic insult. Cerebrolysin injections of 0.1 ml/kg of body weight twice per week were found to provide gross motor and speech deficit improvement.

CONCLUSION

Our literature search emphasizes the positive effects of cerebrolysin for general improvement outcomes. Nevertheless, biomarker establishment is warranted to improve patient outcomes.

Prognostic Risk Factors for Severe Outcome in the Acute Phase of Neonatal Hypoxic-Ischemic Encephalopathy: A Prospective Cohort Study

In the first days after birth, a major focus of research is to identify infants with hypoxic-ischemic encephalopathy at higher risk of death or severe neurological impairment, despite therapeutic hypothermia (TH). This is especially crucial to consider redirection of care, according to neonatal outcome severity. We aimed to seek associations between some neonatal routine parameters, usually recorded in Neonatal Intensive Care Units, and the development of severe outcomes. All consecutive patients prospectively recruited for TH for perinatal asphyxia, born between February 2009 and July 2016, were eligible for this study. Severe outcome was defined as death or major neurological sequelae at one year of age. Among all eligible neonates, the final analysis included 83 patients. Severe outcome was significantly associated with pH and base excess measured in the first hour of life, mode of delivery, Apgar score, Sarnat and Sarnat score, electroencephalogram-confirmed neonatal epileptic seizures, and antiepileptic therapy. Studying univariate analysis by raw relative risk (RR) and 95% confidence intervals (CI), severe outcome was significantly associated with pH (p = 0.011), Apgar score (p = 0.003), Sarnat score (p < 0.001), and Caesarian section (p = 0.015). Conclusions. In addition to clinical examination, we suggest a clinical-electroencephalographic protocol useful to identify neonates at high neurological risk, available before rewarming from TH.

Can we improve our ability to interpret category II fetal heart rate tracings using additional clinical parameters?

OBJECTIVES

This study examined predictive factors, in addition to Category II Fetal Herat Rate (FHR) monitoring that might imply fetal acidosis and risk of asphyxia.

METHODS

This retrospective cohort study compared three groups of patients with Category II FHR monitoring indicating need for imminent delivery. Groups were divided based on fetal cord blood pH: pH≤7.0, 7.0<pH<7.2 and pH≥7.2. Demographics, medical history, delivery data and early neonatal outcomes were reviewed.

RESULTS

The cohort included 417 women. Nine (2.2%) had cord pH≤7.0, 105 (25.2%) pH 7.0 to 7.2 and 303 (72.6%) ad pH≥7.2. Background characteristics, pregnancy follow-up and intrauterine fetal evaluation prior to delivery were similar in all groups. As expected, more patients in the low pH group had cesarean section (55.6%), than vaginal delivery or vacuum extraction (p=0.02). Five-minute Apgar scores were similar in all groups.

CONCLUSIONS

This retrospective study did not detect a specific parameter that could help predict the prognosis of fetal acidosis and risk of asphyxia. As we only included patients with a Category II tracing that was worrisome enough to lead to imminent delivery, it is reasonable to believe that this is due to patient selection, meaning that when the Category II FHR results in decision for prompt delivery, there is no added value in additional clinical characteristics. The evaluation should be expanded to all patients with Category II tracing for better interpretation tools for Category II FHR monitors, as well as a larger study population.

Hypothermia modulates myeloid cell polarization in neonatal hypoxic-ischemic brain injury

Background

Neonatal encephalopathy due to hypoxia–ischemia (HI) is a leading cause of death and disability in term newborns. Therapeutic hypothermia (HT) is the only recommended therapy. However, 30% still suffer from neurological deficits. Inflammation is a major hallmark of HI pathophysiology with myeloid cells being key players, participating either in progression or in resolution of injury-induced inflammation. In the present study, we investigated the impact of HT on the temporal and spatial dynamics of microglia/macrophage polarization after neonatal HI in newborn mice.

Methods

Nine-day-old C57BL/6 mice were exposed to HI through occlusion of the right common carotid artery followed by 1 h hypoxia. Immediately after HI, animals were cooled for 4 h or kept at physiological body core temperature. Analyses were performed at 1, 3 and 7 days post HI. Brain injury, neuronal cell loss, apoptosis and microglia activation were assessed by immunohistochemistry. A broad set of typical genes associated with classical (M1) and alternative (M2) myeloid cell activation was analyzed by real time PCR in ex vivo isolated CD11b⁺ microglia/macrophages. Purity and composition of isolated cells was determined by flow cytometry.

Results

Immediate HT significantly reduced HI-induced brain injury and neuronal loss 7 days post HI, whereas only mild non-significant protection from HI-induced apoptosis and neuronal loss were observed 1 and 3 days after HI. Microglia activation, i.e., Iba-1 immunoreactivity peaked 3 days after HI and was not modulated by HT. However, ex vivo isolated CD11b⁺ cells revealed a strong upregulation of the majority of M1 but also M2 marker genes at day 1, which was significantly reduced by HT and rapidly declined at day 3. HI induced a significant increase in the frequency of peripheral macrophages in sorted CD11b⁺ cells at day 1, which deteriorated until day 7 and was significantly decreased by HT.

Conclusion

Our data demonstrate that HT-induced neuroprotection is preceded by acute suppression of HI-induced upregulation of inflammatory genes in myeloid cells and decreased infiltration of peripheral macrophages, both representing potential important effector mechanisms of HT.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02314-9.

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.

Classical complement pathway inhibition reduces brain damage in a hypoxic ischemic encephalopathy animal model

Perinatal hypoxic ischemic encephalopathy (HIE) remains a major contributor of infant death and long-term disability worldwide. The role played by the complement system in this ischemia-reperfusion injury remains poorly understood. In order to better understand the role of complement activation and other modifiable mechanisms of injury in HIE, we tested the dual-targeting anti-inflammatory peptide, RLS-0071 in an animal model of HIE. Using the well-established HIE rat pup model we measured the effects of RLS-0071 during the acute stages of the brain injury and on long-term neurocognitive outcomes. Rat pups subject to hypoxia-ischemia insult received one of 4 interventions including normothermia, hypothermia and RLS-0071 with and without hypothermia. We measured histopathological effects, brain C1q levels and neuroimaging at day 1 and 21 after the injury. A subset of animals was followed into adolescence and evaluated for neurocognitive function. On histological evaluation, RLS-0071 showed neuronal protection in combination with hypothermia (P = 0.048) in addition to reducing C1q levels in the brain at 1hr (P = 0.01) and at 8 hr in combination with hypothermia (P = 0.005). MRI neuroimaging demonstrated that RLS-0071 in combination with hypothermia reduced lesion volume at 24 hours (P<0.05) as well as decreased T2 signal at day 21 in combination with hypothermia (P<0.01). RLS-0071 alone or in combination with hypothermia improved both short-term and long-term memory. These findings suggest that modulation by RLS-0071 can potentially decrease brain damage resulting from HIE.

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.

Long-term outcome in a noninvasive rat model of birth asphyxia with neonatal seizures: Cognitive impairment, anxiety, epilepsy, and structural brain alterations

OBJECTIVE

Birth asphyxia is a major cause of hypoxic-ischemic encephalopathy (HIE) in neonates and often associated with mortality, neonatal seizures, brain damage, and later life motor, cognitive, and behavioral impairments and epilepsy. Preclinical studies on rodent models are needed to develop more effective therapies for preventing HIE and its consequences. Thus far, the most popular rodent models have used either exposure of intact animals to hypoxia-only, or a combination of hypoxia and carotid occlusion, for the induction of neonatal seizures and adverse outcomes. However, such models lack systemic hypercapnia, which is a fundamental constituent of birth asphyxia with major effects on neuronal excitability. Here, we use a recently developed noninvasive rat model of birth asphyxia with subsequent neonatal seizures to study later life adverse outcome.

METHODS

Intermittent asphyxia was induced for 30 min by exposing male and female postnatal day 11 rat pups to three 7 + 3-min cycles of 9% and 5% O₂ at constant 20% CO₂ . All pups exhibited convulsive seizures after asphyxia. A set of behavioral tests were performed systematically over 14 months following asphyxia, that is, a large part of the rat's life span. Video-electroencephalographic (EEG) monitoring was used to determine whether asphyxia led to the development of epilepsy. Finally, structural brain alterations were examined.

RESULTS

The animals showed impaired spatial learning and memory and increased anxiety when tested at an age of 3-14 months. Video-EEG at ~10 months showed an abundance of spontaneous seizures, which was paralleled by neurodegeneration in the hippocampus and thalamus, and by aberrant mossy fiber sprouting.

SIGNIFICANCE

The present model of birth asphyxia recapitulates several of the later life consequences associated with human HIE. This model thus allows evaluation of the efficacy of novel therapies designed to prevent HIE and seizures following asphyxia, and of how such therapies might alleviate long-term adverse consequences.

Prevalence and risk factors associated with birth asphyxia among neonates delivered in Ethiopia: A systematic review and meta-analysis

BACKGROUND

A number of primary studies in Ethiopia address the prevalence of birth asphyxia and the factors associated with it. However, variations were seen among those studies. The main aim of this systematic review and meta-analysis was carried out to estimate the pooled prevalence and explore the factors that contribute to birth asphyxia in Ethiopia.

METHODS

Different search engines were used to search online databases. The databases include PubMed, HINARI, Cochrane Library and Google Scholar. Relevant grey literature was obtained through online searches. The funnel plot and Egger's regression test were used to see publication bias, and the I-squared was applied to check the heterogeneity of the studies. Cross-sectional, case-control and cohort studies that were conducted in Ethiopia were also be included. The Joanna Briggs Institute checklist was used to assess the quality of the studies and was included in this systematic review. Data entry and statistical analysis were carried out using RevMan 5.4 software and Stata 14.

RESULT

After reviewing 1,125 studies, 26 studies fulfilling the inclusion criteria were included in the meta-analysis. The pooled prevalence of birth asphyxia in Ethiopia was 19.3%. In the Ethiopian context, the following risk factors were identified: Antepartum hemorrhage(OR: 4.7; 95% CI: 3.5, 6.1), premature rupture of membrane(OR: 4.0; 95% CI: 12.4, 6.6), primiparas(OR: 2.8; 95% CI: 1.9, 4.1), prolonged labor(OR: 4.2; 95% CI: 2.8, 6.6), maternal anaemia(OR: 5.1; 95% CI: 2.59, 9.94), low birth weight(OR = 5.6; 95%CI: 4.7,6.7), meconium stained amniotic fluid(OR: 5.6; 95% CI: 4.1, 7.5), abnormal presentation(OR = 5.7; 95% CI: 3.8, 8.3), preterm birth(OR = 4.1; 95% CI: 2.9, 5.8), residing in a rural area (OR: 2.7; 95% CI: 2.0, 3.5), caesarean delivery(OR = 4.4; 95% CI:3.1, 6.2), operative vaginal delivery(OR: 4.9; 95% CI: 3.5, 6.7), preeclampsia(OR = 3.9; 95% CI: 2.1, 7.4), tight nuchal cord OR: 3.43; 95% CI: 2.1, 5.6), chronic hypertension(OR = 2.5; 95% CI: 1.7, 3.8), and unable to write and read (OR = 4.2;95%CI: 1.7, 10.6).

CONCLUSION

According to the findings of this study, birth asphyxia is an unresolved public health problem in the Ethiopia. Therefore, the concerned body needs to pay attention to the above risk factors in order to decrease the country's birth asphyxia.

REVIEW REGISTRATION

PROSPERO International prospective register of systematic reviews (CRD42020165283).

Neurodevelopmental outcome in neonates with hypoxic-ischaemic encephalopathy managed with therapeutic hypothermia in a tertiary-level public hospital outside an intensive care unit setting

BACKGROUND

Management of hypoxic-ischaemic encephalopathy (HIE) by therapeutic hypothermia (TH) is a major challenge in low- and middle-income countries (LMIC) because of the limited resources. Clinicians in LMIC offer this intervention outside neonatal intensive care units (NICU). The effect of this practice on neurodevelopmental outcome is not well known.

AIM

To determine neurodevelopmental outcome in neonates with HIE managed with TH outside NICU settings.

METHODS

: This was a retrospective descriptive study of neonates with HIE managed with TH and followed up for neurodevelopmental assessment at 12 and 18-24 months postnatal age. Patients were reviewed over a 24-month period. Outcome at 12 and 18-24 months was compared.

RESULTS

Of 178 neonates with HIE attending the clinic, there was information on TH for 155 (87.1%), 113 of whom (72.9%) received TH. HIE was moderate in 88% and severe in 10%. Twenty-seven (23.9%) and 16 (14.1%) were assessed at one time-point at 12 or 18-24 months, respectively, 40 (35.3%) at both time-points, and 30 (26.6%) were not assessed. At 18-24 months, 32% had moderate-to-severe disability compared with 6% at 12 months, with the sensitivity and specificity of assessment at 12 months being 50% and 100%, respectively. The disability attrition rate at 18-24 months was 50%.

CONCLUSIONS

The relatively low prevalence of disability (32%) at 18-24 months suggests that use of TH in a Level 2 nursery is feasible and possibly beneficial. More studies are needed to confirm these findings.

ABBREVIATIONS

aEEG: amplitude electroencephalogram; CP: cerebral palsy; GMDS: Griffiths mental developmental scales; GQ: general quotient; HIC: high-income countries; HIE: hypoxic-ischaemic encephalopathy; LMIC: low- and middle-income countries; LTFU: loss to follow-up; NICU: neonatal intensive care unit; TH: therapeutic hypothermia; TOBY: total body hypothermia.

Relationship between Apgar scores and long-term cognitive outcomes in individuals with Down syndrome

This study examined the contribution of the Apgar score at 1 and 5 min after birth to later cognitive functioning in 168 individuals with Down syndrome who were between 6 and 25 years of age at time of cognitive testing. Our results showed that a lower Apgar score at 1 min was related to a worse performance in later cognitive measures of receptive vocabulary, verbal comprehension and production, visual memory and working memory. Results also showed that a lower Apgar score at 5 min was only related to worse later outcomes of verbal comprehension and production and auditory working memory. Our findings suggest a need for future studies investigating how specific perinatal events reflected in the Apgar score are linked to later cognitive functioning in individuals with Down syndrome.

Brief hypoxia in late gestation sheep causes prolonged disruption of fetal electrographic, breathing behaviours and can result in early labour

KEY POINTS

Brief episodes of severe fetal hypoxia can arise in late gestation as a result of interruption of normal umbilical blood flow Systemic parameters and blood chemistry indicate complete recovery within 1-2 hours, although the long-term effects on fetal brain functions are unknown Fetal sheep were subjected to umbilical cord occlusion (UCO) for 10 min at 131 days of gestation, and then monitored intensively until onset of labour or delivery (<145 days of gestation) Normal patterns of fetal behaviour, including breathing movements, episodes of high and low voltage electorcortical activity, eye movements and postural (neck) muscle activity, were disrupted for 3-10 days after the UCO Preterm labour and delivery occurred in a significant number of the pregnancies after UCO compared to the control (sham-UCO) cohort.

ABSTRACT

Complications arising from antepartum events such as impaired umbilical blood flow can cause significant fetal hypoxia. These complications can be unpredictable, as well as difficult to detect, and thus we lack a detailed understanding of the (patho)physiological changes that occur between the antenatal in utero event and birth. In the present study, we assessed the consequences of brief (∼10 min) umbilical cord occlusion (UCO) in fetal sheep at ∼0.88 gestation on fetal plasma cortisol concentrations and fetal behaviour [electrocortical (EcoG), electo-oculargram (EOG), nuchal muscle electromyography (EMG) and breathing activities] in the days following UCO. UCO caused a rapid onset of fetal hypoxaemia, hypercapnia, and acidosis; however, by 6 h, all blood parameters and cardiovascular status were normalized and not different from the control (Sham-UCO) cohort. Subsequently, the incidence of fetal breathing movements decreased compared to the control group, and abnormal behavioural patterns developed over the days following UCO and leading up to the onset of labour, which included increased high voltage and sub-low voltage ECoG and EOG activities, as well as decreased nuchal EMG activity. Fetuses subjected to UCO went into labour 7.9 ± 3.6 days post-UCO (139.5 ± 3.2 days of gestation) compared to the control group fetuses at 13.6 ± 3.3 days post-sham UCO (144 ± 2.2 days of gestation; P < 0.05), despite comparable increases in fetal plasma cortisol and a similar body weight at birth. Thus, a single transient episode of complete UCO late in gestation in fetal sheep can result in prolonged effects on fetal brain activity and premature labour, suggesting persisting effects on fetal cerebral metabolism.

Biphalin, a dimeric opioid peptide, reduces neonatal hypoxia-ischemia brain injury in mice by the activation of PI3K/Akt signaling pathway

Previous studies have demonstrated that the activation of delta opioid receptors is neuroprotective against neonatal hypoxia-ischemia (HI) brain injury. The aim of this study was to investigate the neuroprotective effects of biphalin, a dimeric opioid peptide, in a mouse model of neonatal HI and the underlying mechanisms. On postnatal day 10, mouse pups were subjected to unilateral carotid artery ligation followed by 1 h of hypoxia (10 % O₂ in N₂). For treatment, biphalin (5 mg/kg, 10 mg/kg, 20 mg/kg) was administered intraperitoneally immediately after HI. The opioid antagonist naloxone or phosphatidylinositol-3-kinase inhibitor Ly294002 was administered to determine the underlying mechanisms. Infarct volume, brain edema, phosphorylated Akt and apoptosis-related proteins levels were evaluated by using a combination of 2,3,5-triphenyltetrazolium chloride staining, brain water content and Western blotting at 24 h after HI. The long-term effects of biphalin were evaluated by brain atrophy measurement, Nissl staining and neurobehavioral tests at 3 weeks post-HI. Biphalin (10 mg/kg) significantly reduced the infarct volume and ameliorated brain edema. Biphalin also had long-term protective effects against the loss of ipsilateral brain tissue and resulted in improvements in neurobehavioral outcomes. However, naloxone or Ly294002 abrogated the neuroprotective effects of biphalin. Furthermore, biphalin treatment significantly preserved phosphorylated Akt expression, increased Bcl-2 levels, and decreased Bax and cleaved caspase 3 levels after HI. These effects were also reversed by naloxone and Ly294002 respectively. In conclusion, biphalin protects against HI brain injury in neonatal mice, which might be through activation of the opioid receptor/phosphatidylinositol-3-kinase/Akt signaling pathway.

Multitarget neuroprotection by quercetin: Changes in gene expression in two perinatal asphyxia models

Hypoxic-ischemic encephalopathy (HIE) causes mortality and long-term neurologic morbidities in newborns, affecting pathways related to energy failure, excitotoxicity and oxidative stress that often lead to cell death. The whole process of HIE injury is coupled to changes in the expression of a great array of proteins. A nanoliposomal preparation of the flavonoid quercetin has been shown to exert neuroprotective effects in perinatal asphyxia models. This study aimed to identify neonatal HIE markers and explore the effect of quercetin administration in two perinatal asphyxia models: newborn rats and piglets. In the rat model, nanoliposomal quercetin administration reduced mortality after asphyxia. In the piglet model, quercetin partially overrode the reduction of HIF-1α mRNA levels in the cortex induced by asphyxia. Quercetin administration also reduced increased level of HO-1 mRNA in asphyctic piglets. These results suggest that quercetin neuroprotection might be involved in the regulation of HIF-1α, HO-1 and their targets. A proteomic approach revealed that the glycolytic pathway is strongly regulated by quercetin in both species. We also identified a set of proteins differentially expressed that could be further considered as markers. In piglets, this set includes Acidic Leucine-rich nuclear phosphoprotein 32 (ANP32A), associated with nervous system differentiation, proteins related with death pathways and alpha-enolase which can be converted to neuron-specific enolase, a glycolytic enzyme that may promote neuroprotection. In newborn rats, other promising proteins associated with neurogenesis and neuroprotection emerged, such as dihydropyrimidinase-related proteins, catalytic and regulatory subunits of phosphatases and heterogeneous nuclear ribonucleoprotein K (hnRNPK). Our results show that a nanoliposomal preparation of quercetin, with protective effect in two HIE mammal models, modulates the expression of proteins involved in energy metabolism and other putative neuroprotective signals in the cortex. Identification of these signals could reveal potential molecular pathways involved in disease onset and the novel quercetin neuroprotective strategy.

Predictive factors of death in neonates with hypoxic-ischemic encephalopathy receiving selective head cooling

BACKGROUND

Severe perinatal asphyxia results in multiple organ involvement, neonate hospitalization, and eventual death.

PURPOSE

This study aimed to investigate the predictive factors of death in newborns with hypoxic-ischemic encephalopathy (HIE) receiving selective head cooling.

METHODS

This cross-sectional descriptive-retrospective study was conducted from 2013 to 2018 in Fatemieh Hospital of Hamadan and included 51 newborns who were admitted to the neonatal intensive care unit with a diagnosis of HIE. Selective head cooling for patients with moderate to severe HIE began within 6 hours of birth and continued for 72 hours. The required data for the predictive factors of death were extracted from the patients' medical files, recorded on a premade form, and analyzed using SPSS ver. 16.

RESULTS

Of the 51 neonates with moderate to severe HIE who were treated with selective head cooling, 16 (31%) died. There were significant relationships between death and the need for advanced neonatal resuscitation (P=0.002), need for mechanical ventilation (P=0.016), 1-minute Apgar score (P=0.040), and severely abnormal amplitude-integrated electroencephalography (a-EEG) (P=0.047). Multiple regression of variables or data showed that the need for advanced neonatal resuscitation was an independent predictive factor of death (P=0.0075) and severely abnormal a-EEG was an independent predictive factor of asphyxia severity (P=0.0001).

CONCLUSION

All cases of neonatal death in our study were severe HIE (stage 3). Advanced neonatal resuscitation was an independent predictor of death, while a severely abnormal a-EEG was an independent predictor of asphyxia severity in infants with HIE.

Neonatal Mesenchymal Stem Cell Treatment Improves Myelination Impaired by Global Perinatal Asphyxia in Rats

The effect of perinatal asphyxia (PA) on oligodendrocyte (OL), neuroinflammation, and cell viability was evaluated in telencephalon of rats at postnatal day (P)1, 7, and 14, a period characterized by a spur of neuronal networking, evaluating the effect of mesenchymal stem cell (MSCs)-treatment. The issue was investigated with a rat model of global PA, mimicking a clinical risk occurring under labor. PA was induced by immersing fetus-containing uterine horns into a water bath for 21 min (AS), using sibling-caesarean-delivered fetuses (CS) as controls. Two hours after delivery, AS and CS neonates were injected with either 5 μL of vehicle (10% plasma) or 5 × 10⁴ MSCs into the lateral ventricle. Samples were assayed for myelin-basic protein (MBP) levels; Olig-1/Olig-2 transcriptional factors; Gglial phenotype; neuroinflammation, and delayed cell death. The main effects were observed at P7, including: (i) A decrease of MBP-immunoreactivity in external capsule, corpus callosum, cingulum, but not in fimbriae of hippocampus; (ii) an increase of Olig-1-mRNA levels; (iii) an increase of IL-6-mRNA, but not in protein levels; (iv) an increase in cell death, including OLs; and (v) MSCs treatment prevented the effect of PA on myelination, OLs number, and cell death. The present findings show that PA induces regional- and developmental-dependent changes on myelination and OLs maturation. Neonatal MSCs treatment improves survival of mature OLs and myelination in telencephalic white matter.

Determinants of birth asphyxia among newborns delivered in public hospitals of West Shoa Zone, Central Ethiopia: A case-control study

Birth asphyxia is one of the leading causes of death in low and middle-income countries and the prominent cause of neonatal mortality in Ethiopia. Early detection and managing its determinants would change the burden of birth asphyxia. Thus, this study identified determinants of birth asphyxia among newborns delivered in public hospitals of West Shoa Zone, central Ethiopia. A hospital-based unmatched case-control study was conducted from May to July 2020. Cases were newborns with APGAR (appearance, pulse, grimaces, activity, and respiration) score of <7 at first and fifth minute of birth and controls were newborns with APGAR score of ≥ 7 at first and fifth minute of birth. All newborns with birth asphyxia during the study period were included in the study while; two comparable controls were selected consecutively after each birth asphyxia case. A pre-tested and structured questionnaire was used to collect maternal socio-demographic and antepartum characteristics. The pre-tested checklist was used to retrieve intrapartum and fetal related factors from both cases and controls. The collected data were entered using Epi-Info and analyzed by SPSS. Bi-variable logistic regression analysis was done to identify the association between each independent variable with the outcome variable. Adjusted odds ratio (AOR) with a 95% CI and a p-value of <0.05 was used to identify determinants of birth asphyxia. In this study, prolonged labor (AOR = 4.15, 95% CI: 1.55, 11.06), breech presentation (AOR = 5.13, 95% CI: 1.99, 13.21), caesarean section delivery (AOR = 3.67, 95% CI: 1.31, 10.23), vaginal assisted delivery (AOR = 5.69, 95% CI: 2.17, 14.91), not use partograph (AOR = 3.36, 95% CI: 1.45, 7.84), and low birth weight (AOR = 3.74, 95% CI:1.49, 9.38) had higher odds of birth asphyxia. Prolonged labor, breech presentation, caesarean and vaginal assisted delivery, fails to use partograph and low birth weights were the determinants of birth asphyxia. Thus, health care providers should follow the progress of labor with partograph to early identify prolonged labor, breech presentation and determine the mode of delivery that would lower the burden of birth asphyxia.

Recombinant Human Growth Hormone Activates Neuroprotective Growth Factors in Hypoxic Brain Injury in Neonatal Mice

Perinatal hypoxia severely disrupts cerebral metabolic and maturational programs beyond apoptotic cell death. Antiapoptotic treatments such as erythropoietin are suggested to improve outcomes in hypoxic brain injury; however, the results are controversial. We analyzed the neuroprotective effects of recombinant human growth hormone (rhGH) on regenerative mechanisms in the hypoxic developing mouse brain in comparison to controls. Using an established model of neonatal acute hypoxia (8% O2, 6 hours), P7 mice were treated intraperitoneally with rhGH (4000 µg/kg) 0, 12, and 24 hours after hypoxic exposure. After a regeneration period of 48 hours, expression of hypoxia-inducible neurotrophic factors (erythropoietin [EPO], vascular endothelial growth factor A [VEGF-A], insulin-like growth factors 1 and 2 [IGF-1/-2], IGF binding proteins) and proinflammatory markers was analyzed. In vitro experiments were performed using primary mouse cortical neurons (E14, DIV6). rhGH increased neuronal gene expression of EPO, IGF-1, and VEGF (P < .05) in vitro and diminished apoptosis of hypoxic neurons in a dose-dependent manner. In the developing brain, rhGH treatment led to a notable reduction of apoptosis in the subventricular zone and hippocampus (P < .05), abolished hypoxia-induced downregulation of IGF-1/IGF-2 expression (P < .05), and led to a significant accumulation of endogenous EPO protein and anti-inflammatory effects through modulation of interleukin-1β and tumor necrosis factor α signaling as well as upregulation of cerebral phosphorylated extracellularly regulated kinase 1/2 levels (ERK1/2). Indicating stabilizing effects on the blood-brain barrier (BBB), rhGH significantly modified cerebrovascular occludin expression. Thus, we conclude that rhGH mediates neuroprotective effects by the activation of endogenous neurotrophic growth factors and BBB stabilization. In addition, the modification of ERK1/2 pathways is involved in neuroprotective actions of rhGH. The present study adds further evidence that pharmacologic activation of neurotrophic growth factors may be a promising target for neonatal neuroprotection.

What is the Best Predictor of Phenobarbital Pharmacokinetics to Use for Initial Dosing in Neonates?

Phenobarbital is a first-line treatment of various seizure types in newborns. Dosage individualization maximizing the proportion of patients with drug levels in therapeutic range or sufficient treatment response is still challenging. The aim of this review was to summarize the available evidence on phenobarbital pharmacokinetics in neonates and to identify its possible covariates suitable for individualization of initial drug dosing. Several covariates have been considered: body weight and height, body surface area, gestational and postnatal age, laboratory parameters of renal and hepatic functions, asphyxia, therapeutic hypothermia, extracorporeal membrane oxygenation (ECMO), drug interactions, and genetic polymorphisms. The most frequently studied and well-founded covariate for the estimation of phenobarbital dosing is actual body weight. Loading dose of 15-20 mg/kg followed by a maintenance dose of 3-5 mg/kg/day seems to be accurate. However, the evidence for the other covariates with respect to dosing individualization is not sufficient. Doses at the lower limit of suggested range should be preferred in patients with severe asphyxia, while the upper limit of the range should be targeted in neonates receiving ECMO support.

Redox Effects of Molecular Hydrogen and Its Therapeutic Efficacy in the Treatment of Neurodegenerative Diseases

Oxidative stress (OS) and neuroinflammatory stress affect many neurological disorders. Despite the clinical significance of oxidative damage in neurological disorders, still, no effective and safe treatment methods for neuro diseases are available. With this, molecular hydrogen (H2) has been recently reported as an antioxidant and anti-inflammatory agent to treat several oxidative stress-related diseases. In animal and human clinical trials, the routes for H2 administration are mainly categorized into three types: H2 gas inhalation, H2 water dissolving, and H2-dissolved saline injection. This review explores some significant progress in research on H2 use in neurodegenerative diseases (NDs), including Alzheimer’s disease, Parkinson’s disease, neonatal disorders of the brain, and other NDs (retinal ischemia and traumatic brain injury). Even though most neurological problems are not currently curable, these studies have shown the therapeutic potential for prevention, treatment, and mitigation of H2 administration. Several possible H2-effectors, including cell signaling molecules and hormones, which prevent OS and inflammation, will also be addressed. However, more clinical and other related studies are required to evaluate the direct H2 target molecule.

Hearing Impairment in Infants with Hypoxic Ischemic Encephalopathy Treated with Hypothermia

Therapeutic hypothermia acts as the standard of care for infants with moderate to severe hypoxic ischemic encephalopathy (HIE). A proportion of neonates who undergo hypothermia due to HIE have shown to develop various degrees of hearing impairment. Analyzing and identifying infants at high risk of developing hearing difficulties is fundamental for early intervention of such auditory complications. The aim was to assess clinical factors in the development of hearing impairment following therapeutic hypothermia in HIE infants. A retrospective analysis was performed on infants hospitalized in our neonatology department in Poznan University of Medical Sciences, Poland. All infants experienced moderate to severe HIE, and were treated with therapeutic hypothermia. Risk factors for hearing impairment were identified in all infants included in the study. Clinical data during hospital stay and follow-up hearing status were analyzed. A total of 87 HIE infants were included in the study. Seventy-six infants (40 male and 36 female) had otoacoustic emission (OAE) examination following birth, of which 14 (18.4%) demonstrated abnormal (positive) results. Infants with abnormal OAE results had significantly lower blood pH (6.86 ± 0.16, p = 0.001) and base excess (BE) (-22.46 ± 2.59, p = 0.006). Of the 49 infants who returned for follow-up assessment, 4 (8.2%) were diagnosed with sensorineural bilateral hearing impairment (1 infant, mild [<40 dB], 2 moderate [41-70 dB], and 1 profound [>90 dB]). The biochemical analysis following birth revealed significantly lower umbilical BE levels (-23.90 ± 4.99, p = 0.041) and higher lactate levels (160.67 ± 4.93, p = 0.019) in the infants with eventual sensorineural hearing deficit. Infants with moderate or severe HIE are at risk of delayed onset hearing loss. Diligent efforts to monitor auditory status are required, even if early screening results for hearing are insignificant. Exploring biochemical parameters, such as lactate, BE, and blood pH, can prove beneficial in identifying HIE infants at risk of developing a hearing impairment.

Quantitative approach to early neonatal EEG visual analysis in hypoxic-ischemic encephalopathy severity: Bridging the gap between eyes and machine

OBJECTIVES

To identify relevant quantitative parameters for early classification of neonatal hypoxic-ischemic encephalopathy (HIE) severity from conventional EEGs.

METHODS

Ninety EEGs, recorded in full-term infants within 6 h of life after perinatal hypoxia, were visually classified according to the French EEG classification into three groups of increasing HIE severity. Physiologically significant EEG features (signal amplitude, continuity and frequency content) were automatically quantified using different parameters. The EEG parameters selection was based on their ability to reproduce the visual EEG classification. Post hoc analysis based on clinical outcome was performed.

RESULTS

Six EEG parameters were selected, with overall EEG classification performances between 61% and 70%. All parameters differed significantly between group 3 (severe) and groups 1 (normal-mildly abnormal) and 2 (moderate) EEGs (p < 0.001). Amplitude and discontinuity parameters were different between the 3 groups (p < 0.01) and were also the best predictors of clinical outcome. Conversely, pH and lactate did not differ between groups.

DISCUSSION

This study provides quantitative EEG parameters that are complementary to visual analysis as early markers of neonatal HIE severity. These parameters could be combined in a multiparametric algorithm to improve their classification performance. The absence of relationship between pH lactate and HIE severity reinforces the central role of early neonatal EEG.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Reduce Neuroinflammation, Promote Neural Cell Proliferation and Improve Oligodendrocyte Maturation in Neonatal Hypoxic-Ischemic Brain Injury

Background: Neonatal encephalopathy caused by hypoxia-ischemia (HI) is a major cause of childhood mortality and disability. Stem cell-based regenerative therapies seem promising to prevent long-term neurological deficits. Our previous work in neonatal HI revealed an unexpected interaction between mesenchymal stem/stromal cells (MSCs) and the brains' microenvironment leading to an altered therapeutic efficiency. MSCs are supposed to mediate most of their therapeutic effects in a paracrine mode via extracellular vesicles (EVs), which might be an alternative to cell therapy. In the present study, we investigated the impact of MSC-EVs on neonatal HI-induced brain injury.

Methods: Nine-day-old C57BL/6 mice were exposed to HI through ligation of the right common carotid artery followed by 1 h hypoxia (10% oxygen). MSC-EVs were injected intraperitoneally 1, 3, and 5 days after HI. One week after HI, brain injury was evaluated by regional neuropathological scoring, atrophy measurements and immunohistochemistry to assess effects on neuronal, oligodendrocyte and vessel densities, proliferation, oligodendrocyte maturation, myelination, astro-, and microglia activation. Immunohistochemistry analyses were complemented by mRNA expression analyses for a broad set of M1/M2- and A1/A2-associated molecules and neural growth factors.

Results: While total neuropathological scores and tissue atrophy were not changed, MSC-EVs significantly protected from HI-induced striatal tissue loss and decreased micro- and astroglia activation. MSC-EVs lead to a significant downregulation of the pro-inflammatory cytokine TNFa, accompanied by a significant upregulation of the M2 marker YM-1 and the anti-inflammatory cytokine TGFb. MSC-EVs significantly decreased astrocytic expression of the A1 marker C3, concomitant with an increased expression of neural growth factors (i.e., BDNF, VEGF, and EGF). These alterations were associated with an increased neuronal and vessel density, coinciding with a significant increase of proliferating cells in the neurogenic sub-ventricular zone juxtaposed to the striatum. MSC-EV-mediated neuroprotection went along with a significant improvement of oligodendrocyte maturation and myelination.

Conclusion: The present study demonstrates that MSC-EVs mediate anti-inflammatory effects, promote regenerative responses and improve key developmental processes in the injured neonatal brain. The present results suggest different cellular target mechanisms of MSC-EVs, preventing secondary HI-induced brain injury. MSC-EV treatment may be a promising alternative to risk-associated cell therapies in neonatal brain injury.

Umbilical cord lactate compared with pH as predictors of intrapartum asphyxia

Despite advances in fetal monitoring during labor, one of the most critical causes of neonatal death and neurologic injuries remains intrapartum asphyxia. Umbilical cord gases can be used to detect acidosis and fetal distress. We conducted a retrospective, multicenter study to evaluate umbilical cord blood pH and lactate as a mean of evaluating the degree of intrapartum hypoxia and also to establish which of the two is more reliable in predicting morbidity in term neonates. The present study utilized a total of 124 cases that met the criteria for intrapartum asphyxia and 150 normal term newborns that were randomly selected as case control. Both umbilical cord lactate and pH proved to be accurate predictors of neonatal morbidity caused by intrapartum hypoxia. Lactate proved to be superior to pH in predicting adverse neonatal outcome. The greatest sensibility and specificity in predicting intrapartum asphyxia were achieved in our study by using a cutoff value of 3.75 mmol/l for lactate and 7.24 for pH.