Perinatal hypoxic-ischemic encephalopathy

Clinical outcome prediction with an automated EEG trend, Brain State of the Newborn, after perinatal asphyxia

OBJECTIVE

To evaluate the utility of a fully automated deep learning -based quantitative measure of EEG background, Brain State of the Newborn (BSN), for early prediction of clinical outcome at four years of age.

METHODS

The EEG monitoring data from eighty consecutive newborns was analyzed using the automatically computed BSN trend. BSN levels during the first days of life (a of total 5427 hours) were compared to four clinical outcome categories: favorable, cerebral palsy (CP), CP with epilepsy, and death. The time dependent changes in BSN-based prediction for different outcomes were assessed by positive/negative predictive value (PPV/NPV) and by estimating the area under the receiver operating characteristic curve (AUC).

RESULTS

The BSN values were closely aligned with four visually determined EEG categories (p < 0·001), as well as with respect to clinical milestones of EEG recovery in perinatal Hypoxic Ischemic Encephalopathy (HIE; p < 0·003). Favorable outcome was related to a rapid recovery of the BSN trend, while worse outcomes related to a slow BSN recovery. Outcome predictions with BSN were accurate from 6 to 48 hours of age: For the favorable outcome, the AUC ranged from 95 to 99% (peak at 12 hours), and for the poor outcome the AUC ranged from 96 to 99% (peak at 12 hours). The optimal BSN levels for each PPV/NPV estimate changed substantially during the first 48 hours, ranging from 20 to 80.

CONCLUSIONS

We show that the BSN provides an automated, objective, and continuous measure of brain activity in newborns.

SIGNIFICANCE

The BSN trend discloses the dynamic nature that exists in both cerebral recovery and outcome prediction, supports individualized patient care, rapid stratification and early prognosis.

Diabetes drugs activate neuroprotective pathways in models of neonatal hypoxic-ischemic encephalopathy

Hypoxic-ischaemic encephalopathy (HIE) arises from diminished blood flow and oxygen to the neonatal brain during labor, leading to infant mortality or severe brain damage, with a global incidence of 1.5 per 1000 live births. Glucagon-like Peptide 1 Receptor (GLP1-R) agonists, used in type 2 diabetes treatment, exhibit neuroprotective effects in various brain injury models, including HIE. In this study, we observed enhanced neurological outcomes in post-natal day 10 mice with surgically induced hypoxic-ischaemic (HI) brain injury after immediate systemic administration of exendin-4 or semaglutide. Short- and long-term assessments revealed improved neuropathology, survival rates, and locomotor function. We explored the mechanisms by which GLP1-R agonists trigger neuroprotection and reduce inflammation following oxygen-glucose deprivation and HI in neonatal mice, highlighting the upregulation of the PI3/AKT signalling pathway and increased cAMP levels. These findings shed light on the neuroprotective and anti-inflammatory effects of GLP1-R agonists in HIE, potentially extending to other neurological conditions, supporting their potential clinical use in treating infants with HIE.

NF-κB as an Inducible Regulator of Inflammation in the Central Nervous System

The NF-κB (nuclear factor K-light-chain-enhancer of activated B cells) transcription factor family is critical for modulating the immune proinflammatory response throughout the body. During the resting state, inactive NF-κB is sequestered by IκB in the cytoplasm. The proteasomal degradation of IκB activates NF-κB, mediating its translocation into the nucleus to act as a nuclear transcription factor in the upregulation of proinflammatory genes. Stimuli that initiate NF-κB activation are diverse but are canonically attributed to proinflammatory cytokines and chemokines. Downstream effects of NF-κB are cell type-specific and, in the majority of cases, result in the activation of pro-inflammatory cascades. Acting as the primary immune responders of the central nervous system, microglia exhibit upregulation of NF-κB upon activation in response to pathological conditions. Under such circumstances, microglial crosstalk with other cell types in the central nervous system can induce cell death, further exacerbating the disease pathology. In this review, we will emphasize the role of NF-κB in triggering neuroinflammation mediated by microglia.

Human Placenta Derived Mesenchymal Stem Cells Transplantation Reducing Cellular Apoptosis in Hypoxic-Ischemic Neonatal Rats by Down-Regulating Semaphorin 3A/Neuropilin-1

Neonatal hypoxic-ischemic encephalopathy (HIE) is an abnormal neurological condition caused by hypoxic-ischemic damage during the perinatal period. Human placenta derived mesenchymal stem cells (hPMSCs) have been shown to have protective and reparative effects in various neurological diseases; however, the research on HIE is insufficient. This study aimed to establish a rat model of HIE and transplant hPMSCs through the lateral ventricle after hypoxic-ishcemic (HI) brain damage to observe its protective effects and mechanisms, with a focus on brain apoptosis compared among groups. Differentially expressed apoptosis-related proteins were screened using a rat cytokine array and subsequent verification. Neuropilin-1 (NRP-1) and Semaphorin 3A (Sema 3A) were selected for further investigation. Western blotting was used to quantify the expression of Sema 3A and the proteins related to PI3K/Akt/mTOR signaling pathway. Exogenous Sema 3A was added to evaluate the effects of Sema 3A/NRP-1 on hPMSCs following HI injury. hPMSCs transplantation ameliorated HI-induced pathological changes, reduced apoptosis, and improved long-term neurological prognosis. Furthermore, Sema 3A/NRP-1 was a key regulator in reducing HI-induced apoptosis after hPMSCs transplantation. hPMSCs inhibited the expression of Sema 3A/NRP-1 and activated the PI3K/Akt/mTOR signaling pathway. Additionally, exogenous Sema 3A abolished the protective effects of hPMSCs against HI. In conclusion, hPMSCs transplantation reduced apoptosis and improved long-term neurological prognosis after HI by downregulating Sema 3A/NRP-1 expression and activating the PI3K/Akt/mTOR signaling pathway.

Calpain as a Therapeutic Target for Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a complex pathophysiological process with multiple links and factors. It involves the interaction of inflammation, oxidative stress, and glucose metabolism, and results in acute and even long-term brain damage and impairment of brain function. Calpain is a family of Ca2+-dependent cysteine proteases that regulate cellular function. Calpain activation is involved in cerebral ischemic injury, and this involvement is achieved by the interaction among Ca2+, substrates, organelles, and multiple proteases in the neuronal necrosis and apoptosis pathways after cerebral ischemia. Many calpain inhibitors have been developed and tested in the biochemical and biomedical fields. This study reviewed the potential role of calpain in the treatment of HIE and related mechanism, providing new insights for future research on HIE.

Exploring the Neuroprotective Effects of Lithium in Ischemic Stroke: A literature review

Ischemic stroke ranks among the foremost clinical causes of mortality and disability, instigating neuronal degeneration, fatalities, and various sequelae. While standard treatments, such as intravenous thrombolysis and endovascular thrombectomy, prove effective, they come with limitations. Hence, there is a compelling need to develop neuroprotective agents capable of improving the functional outcomes of the nervous system. Numerous preclinical studies have demonstrated that lithium can act in multiple molecular pathways, including glycogen synthase kinase 3(GSK-3), the Wnt signaling pathway, the mitogen-activated protein kinase (MAPK)/ extracellular signal-regulated kinase (ERK) signaling pathway, brain-derived neurotrophic factor (BDNF), mammalian target of rapamycin (mTOR), and glutamate receptors. Through these pathways, lithium has been shown to affect inflammation, autophagy, apoptosis, ferroptosis, excitotoxicity, and other pathological processes, thereby improving central nervous system (CNS) damage caused by ischemic stroke. Despite these promising preclinical findings, the number of clinical trials exploring lithium's efficacy remains limited. Additional trials are imperative to thoroughly ascertain the effectiveness and safety of lithium in clinical settings. This review delineates the mechanisms underpinning lithium's neuroprotective capabilities in the context of ischemic stroke. It elucidates the intricate interplay between these mechanisms and sheds light on the involvement of mitochondrial dysfunction and inflammatory markers in the pathophysiology of ischemic stroke. Furthermore, the review offers directions for future research, thereby advancing the understanding of the potential therapeutic utility of lithium and establishing a theoretical foundation for its clinical application.

Neuroquantification enhances the radiological evaluation of term neonatal hypoxic-ischaemic cerebral injuries

Background

Injury patterns in hypoxic-ischaemic brain injury (HIBI) are well recognised but there are few studies evaluating cerebral injury using neuroquantification models.

Objectives

Quantification of brain volumes in a group of patients with clinically determined cerebral palsy.

Method

In this retrospective study, 297 children with cerebral palsy were imaged for suspected HIBI with analysis of various cerebral substrates. Of these, 96 children over the age of 3 years with a clinical diagnosis of cerebral palsy and abnormal MRI findings underwent volumetric analyses using the NeuroQuant® software solution. The spectrum of volumetric changes and the differences between the various subtypes (and individual subgroups) of HIBI were compared.

Results

Compared with the available normative NeuroQuant® database, the average intracranial volume was reduced to the 1st percentile in all patient groups (p < 0.001). Statistically significant differences were observed among the types and subgroups of HIBI. Further substrate volume reductions were identified and described involving the thalami, brainstem, hippocampi, putamina and amygdala. The combined volumes of five regions of interest (frontal pole, putamen, hippocampus, brainstem and paracentral lobule) were consistently reduced in the Rolandic basal ganglia-thalamus (RBGT) subtype.

Conclusion

This study determined a quantifiable reduction of intracranial volume in all subtypes of HIBI and predictable selective cerebral substrate volume reduction in subtypes and subgroups. In the RBGT subtype, a key combination of five substrate injuries was consistently noted, and thalamic, occipital lobe and brainstem volume reduction was also significant when compared to the watershed subtype.

Contribution

This study demonstrates the value of integrating an artificial intelligence programme into the radiologists' armamentarium serving to quantify brain injuries more accurately in HIBI. Going forward this will be an inevitable evolution of daily radiology practice in many fields of medicine, and it would be beneficial for radiologists to embrace these technological innovations.

Effects of prenatal mobile phone radiation exposure on MMP9 expression: Implications for inflammation, oxidative stress, and sensory-motor impairment after neonatal hypoxia- ischemia in rats

Objective

Non-ionizing radiofrequency radiation, which finds application in various sectors such as industry, commerce, medicine, and particularly in mobile phone technology, has emerged as a topic of significant concern during pregnancy. The aim of this study was to investigate the effect of cell phone radio-frequency (RF) radiation during pregnancy on the Matrix metalloproteinase 2 (MMP-2) and (MMP-9) 9 expressions after neonatal hypoxia-ischemia (HI) in rats.

Materials and methods

Two groups were formed by randomly assigning female Wistar rats: Group 1 consisted of female rats that were not exposed to RF radiation during pregnancy, while Group 2 comprised female rats that were exposed to RF radiation during pregnancy. After delivery, male offspring were divided into four groups including: (a) SHAM, (b) Exposure (EXP), (c) hypoxia-ischemia (HI), (d) HI/Exposure (HI/EXP). Seven days after HI induction, neurobehavioral tests were performed, and then brain tissue was taken from the skull to measure MMP-2 and MMP-9 expressions, inflammation, oxidative stress, infarct volume and cerebral edema.

Results

MMP-9 mRNA expression in the HI/EXP group was significantly higher than the HI, SHAM and EXP groups. MMP-2 mRNA expression levels in the HI group were significantly higher than Sham and the EXP groups.TNF-α and Total oxidant capacity (TOC) levels in the HI/EXP group were significantly higher than HI, EXP and SHAM groups. Total antioxidant capacity (TAC) level in the HI/EXP group were significantly lower than HI, EXP and SHAM groups. Cerebral edema and infarct volume in the HI/EXP group were significantly greater than the HI group. Sensory-motor function was significantly weaker in HI/EXP as compared HI group.

Conclusion

Our findings indicate that during pregnancy, exposure to mobile phone RF radiation intensifies damage from HI in rat pups by elevating MMP-9 activity.

Consequences of oxygen deprivation on myelination and sex-dependent alterations

Oxygen deprivation is one of the main causes of morbidity and mortality in newborns, occurring with a higher prevalence in preterm infants, reaching 20 % to 50 % mortality in newborns in the perinatal period. When they survive, 25 % exhibit neuropsychological pathologies, such as learning difficulties, epilepsy, and cerebral palsy. White matter injury is one of the main features found in oxygen deprivation injury, which can lead to long-term functional impairments, including cognitive delay and motor deficits. The myelin sheath accounts for much of the white matter in the brain by surrounding axons and enabling the efficient conduction of action potentials. Mature oligodendrocytes, which synthesize and maintain myelination, also comprise a significant proportion of the brain's white matter. In recent years, oligodendrocytes and the myelination process have become potential therapeutic targets to minimize the effects of oxygen deprivation on the central nervous system. Moreover, evidence indicate that neuroinflammation and apoptotic pathways activated during oxygen deprivation may be influenced by sexual dimorphism. To summarize the most recent research about the impact of sexual dimorphism on the neuroinflammatory state and white matter injury after oxygen deprivation, this review presents an overview of the oligodendrocyte lineage development and myelination, the impact of oxygen deprivation and neuroinflammation on oligodendrocytes in neurodevelopmental disorders, and recent reports about sexual dimorphism regarding the neuroinflammation and white matter injury after neonatal oxygen deprivation.

Citicoline in hypoxic ischemic encephalopathy in neonates: a randomized controlled trial

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is one of the major complications that can lead to death or disability in neonates. We assessed the effect of citicoline as a neuroprotector in neonates with moderate and severe HIE.

METHODS

This clinical trial was carried on 80 neonates with moderate to severe HIE who were not candidates for therapeutic cooling. They were subdivided randomly into two groups; citicoline treatment group which included 40 neonates who received citicoline 10 mg / kg /12 h IV for 4 weeks plus other supportive measures and the control group which included 40 neonates who were managed with placebo and the same supportive measures. All patients were evaluated for duration of mechanical ventilation (MV), need for inotropes, seizures (type, frequency, and duration), and duration of NICU. Cranial ultrasounds and brain magnetic resonance image (MRI) were performed for all included neonates after 4 weeks of treatment. Follow- ups of all neonates for the neurodevelopmental outcomes were done at 3, 6, 9, and 12 months.

RESULTS

There was a significant reduction in the number of neonates having seizures after discharge in the citicoline-treated group (2 neonates) compared to the control group (11 neonates). Cranial ultrasound and MRI findings at 4 weeks were significantly better in the treatment group compared to the control group. Moreover, neurodevelopmental outcome showed significant improvement at 9 and 12 months in the citicoline treated neonates compared to the control group. There was statistically significant reduction in the duration of seizures, NICU stay, inotrope use, and MV in the treatment group compared to the control group. Citicoline was well tolerated with no remarkable side effects.

CONCLUSION

Citicoline could be a promising neuroprotector drug in neonates with HIE.

TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT03949049). Registered at 14 May 2019, https://clinicaltrials.gov/ct2/show/NCT03949049.

Perinatal Stressors as a Factor in Impairments to Nervous System Development and Functions: Review of In Vivo Models

The human body is faced with stress throughout ontogeny. At the stage of intrauterine development, the mother’s body serves as a source of resources and most of the humoral factors supporting the development of the fetus. In normal conditions, maternal stress-related humoral signals (e.g., cortisol) regulate fetal development; however, distress (excessive pathological stress) in the perinatal period leads to serious and sometimes irreversible changes in the developing brain. The mother being in an unfavorable psychoemotional state, toxins and teratogens, environmental conditions, and severe infectious diseases are the most common risk factors for the development of perinatal nervous system pathology in the modern world. In this regard, the challenge of modeling situations in which prenatal or early postnatal stresses lead to serious impairments to brain development and functioning is extremely relevant. This review addresses the various models of perinatal pathology used in our studies (hypoxia, exposure to valproate, hyperserotoninemia, alcoholization), and assesses the commonality of the mechanisms of the resulting disorders and behavioral phenotypes forming in these models, as well as their relationship with models of perinatal pathology based on the impact of psychoemotional stressors.

Myricetin attenuates hypoxic-ischemic brain damage in neonatal rats via NRF2 signaling pathway

Introduction: Hypoxic-ischemic encephalopathy (HIE) is a crucial cause of neonatal death and neurological sequelae, but currently there is no effective therapy drug for HIE. Both oxidative stress and apoptosis play critical roles in the pathological development of HIE. Myricetin, a naturally extracted flavonol compound, exerts remarkable effects against oxidative stress, apoptosis, and inflammation. However, the role and underlying molecular mechanism of myricetin on HIE remain unclear. Methods: In this study, we established the neonatal rats hypoxic-ischemic (HI) brain damage model in vivo and CoCl₂ induced PC1₂ cell model in vitro to explore the neuroprotective effects of myricetin on HI injury, and illuminate the potential mechanism. Results: Our results showed that myricetin intervention could significantly reduce brain infarction volume, glia activation, apoptosis, and oxidative stress marker levels through activating NRF2 (Nuclear factor-E2-related factor 2) and increase the expressions of NRF2 downstream proteins NQO-1 and HO-1. In addition, the NRF2 inhibitor ML385 could significantly reverse the effects of myricetin. Conclusion: This study found that myricetin might alleviate oxidative stress and apoptosis through NRF2 signaling pathway to exert the protective role for HI injury, which suggested that myricetin might be a promising therapeutic agent for HIE.

The Role of Melatonin in Pregnancy and the Health Benefits for the Newborn

In the last few years, there have been significant evolutions in the understanding of the hormone melatonin in terms of its physiology, regulatory role, and potential utility in various domains of clinical medicine. Melatonin's properties include, among others, the regulation of mitochondrial function, anti-inflammatory, anti-oxidative and neuro-protective effects, sleep promotion and immune enhancement. As it is also bioavailable and has little or no toxicity, it has been proposed as safe and effective for the treatment of numerous diseases and to preserve human health. In this manuscript, we tried to evaluate the role of melatonin at the beginning of human life, in pregnancy, in the fetus and in newborns through newly published literature studies.

Transcriptional regulation of NRF1 on metabotropic glutamate receptors in a neonatal hypoxic‑ischemic encephalopathy rat model

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE) is a kind of brain injury that causes severe neurological disorders in newborns. Metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors (iGluRs) are significantly associated with HIE and are involved in ischemia-induced excitotoxicity. This study aimed to investigate the upstream mechanisms of mGluRs and the transcriptional regulation by nuclear respiratory factor 1 (NRF1).

METHODS

The rat model of neonatal HIE was created using unilateral carotid artery ligation and in vitro oxygen-glucose deprivation paradigm. We used western blot, immunofluorescence, Nissl staining, and Morris water maze to investigate the impact of NRF1 on brain damage and learning memory deficit by HIE. We performed ChIP and luciferase activities to identify the transcriptional regulation of NRF1 on mGluRs.

RESULTS

The neuronal NRF1 and some glutamatergic genes expression synchronously declined in infarcted tissues. The NRF1 overexpression effectively restored the expression of some glutamatergic genes and improved cognitive performance. NRF1 regulated some members of mGluRs and iGluRs in hypoxic-ischemic neurons. Finally, NRF1 is bound to the promoter regions of Grm1, Grm2, and Grm8 to activate their transcription.

CONCLUSIONS

NRF1 is involved in the pathology of the neonatal HIE rat model, suggesting a novel therapeutic approach to neonatal HIE.

IMPACT

NRF1 and some glutamatergic genes were synchronously downregulated in the infarcted brain of the neonatal HIE rat model. NRF1 overexpression could rescue cognitive impairment caused by the neonatal HIE rat model. NRF1 regulated the expressions of Grm1, Grm2, and Grm8, which activated their transcription by binding to the promoter regions.

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.

The effect of sulforaphane on perinatal hypoxic-ischemic brain injury in rats

Perinatal hypoxic-ischemic insult (HII) is one of the main devastating causes of morbidity and mortality in newborns. HII induces brain injury which evolves to neurological sequelae later in life. Hypothermia is the only therapeutic approach available capable of diminishing brain impairment after HII. Finding a novel therapeutic method to reduce the severity of brain injury and its consequences is critical in neonatology. The present paper aimed to evaluate the effect of sulforaphane (SFN) pre-treatment on glucose metabolism, neurodegeneration, and functional outcome at the acute, sub-acute, and sub-chronic time intervals in the experimental model of perinatal hypoxic-ischemic insult in rats. To estimate the effect of SFN on brain glucose uptake we have performed 18F-deoxyglucose (FDG) microCT/PET. The activity of FDG was determined in the hippocampus and sensorimotor cortex. Neurodegeneration was assessed by histological analysis of Nissl-stained brain sections. To investigate functional outcomes a battery of behavioral tests was employed. We have shown that although SFN possesses a protective effect on glucose uptake in the ischemic hippocampus 24 h and 1 week after HII, no effect has been observed in the motor cortex. We have further shown that the ischemic hippocampal formation tends to be thinner in HIE and SFN treatment tends to reverse this pattern. We have observed subtle chronic movement deficit after HII detected by ladder rung walking test with no protective effect of SFN. SFN should be thus considered as a potent neuroprotective drug with the capability to interfere with pathophysiological processes triggered by perinatal hypoxic-ischemic insult.

Dihydroartemisinin attenuates hypoxic-ischemic brain damage in neonatal rats by inhibiting oxidative stress

Neonatal hypoxic-ischemic encephalopathy (HIE) induced by perinatal asphyxia is a major cause of neurological disability among infants. Dihydroartemisinin (DHA), derived from artemisinin, well known as an anti-malarial medicine, was proved to be able to inhibit oxidative stress and inflammation. However, whether those functions of DHA play roles in hypoxic-ischemic brain damage (HIBD), an animal model of HIE in patient which also been observed to have oxidative stress and inflammation, is unknown. In this study, we demonstrated that the DHA treatment on newborn rats significantly relieved the neuron loss and motor and cognitive impairment caused by HIBD. One of the underlying mechanisms is that DHA enhanced the anti-oxidant capacity of HIBD rats by up-regulating the total antioxidant capacity (T-AOC), gluathione reductase (GR) and catalase (CAT) while down regulating the pro-oxidative substances including hydrogen peroxide (H₂O₂), total nitric oxide synthase (T-NOS) and inducible nitric oxide synthase (iNOS). Thus, our study illustrated that DHA could alleviate the damage of brains and improve the cognitive and motor function of HIBD rats by inhibiting oxidative stress, provided an opportunity to interrogate potential therapeutics for affected HIE patients.

Asymmetry Index Evaluation of Cerebral Volume and Cerebral Blood Flow in Neonatal Hypoxic–Ischemic Encephalopathy

The aim of the present study was to longitudinally evaluate the differences in cerebral volume and cerebral blood flow (CBF) on the right and left sides in rats with neonatal hypoxic–ischemic encephalopathy (HIE) using magnetic resonance imaging and the Rice–Vannucci model. Unilateral ligation of the left common carotid artery was performed on 8-day-old rats, followed by mild (1 h, n = 6) or severe (2 h, n = 7) hypoxic exposure. T2-weighted (T2W) and CBF images were obtained at 1 h and 1, 3, and 7 days following the HI insult. The cerebral volume (Vlesion and Vcontrol), CBF in both hemispheres (lesion and control sides), and asymmetry indices of the cerebral volume (AIvolume) and CBF (AICBF) were calculated for each group. Slight hyperintensities were noted in the lesion-side hemispheres on T2W images at 1 h and 1 day in both groups, as were pronounced hyperintensities at days 3 and 7 in the severe group. AIvolume was positive (Vlesion > Vcontrol) in the mild and severe groups until days 1 and 3, respectively, and changed to negative on days 3 and 7 in the mild and severe groups. These results suggest that the prolonged positive AIvolume prior to day 3 in the severe group was caused by long-term cell swelling following severe HI insult.

Role of Nuclear-Receptor-Related 1 in the Synergistic Neuroprotective Effect of Umbilical Cord Blood and Erythropoietin Combination Therapy in Hypoxic Ischemic Encephalopathy

Neonatal hypoxic–ischemic encephalopathy (HIE) results in neurological impairments; cell-based therapy has been suggested as a therapeutic avenue. Previous research has demonstrated the synergistically potentiated therapeutic efficacy of human umbilical cord blood (UCB) by combining recombinant human erythropoietin (EPO) treatment for recovery from HIE. However, its molecular mechanism is not entirely understood. In the present study, we analyzed the mechanisms underlying the effect of combination treatment with EPO and UCB by transcriptomic analysis, followed by gene enrichment analysis. Mouse HIE model of the neonate was prepared and randomly divided into five groups: sham, HIE, and UCB, EPO, and UCB+EPO treatments after HIE. A total of 376 genes were differentially expressed when |log2FC| ≥ 1-fold change expression values were considered to be differentially expressed between UCB+EPO and HIE. Further assessment through qRT-PCR and gene enrichment analysis confirmed the expression and correlation of its potential target, Nurr1, as an essential gene involved in the synergistic effect of the UCB+EPO combination. The results indicated the remarkable activation of Wnt/β-catenin signaling by reducing the infarct size by UCB+EPO treatment, accompanied by Nurr1 activity. In conclusion, these findings suggest that the regulation of Nurr1 through the Wnt/β-catenin pathway exerts a synergistic neuroprotective effect in UCB and EPO combination treatment.

Plinia trunciflora Extract Administration Prevents HI-Induced Oxidative Stress, Inflammatory Response, Behavioral Impairments, and Tissue Damage in Rats

The disruption of redox homeostasis and neuroinflammation are key mechanisms in the pathogenesis of brain hypoxia–ischemia (HI); medicinal plants have been studied as a therapeutic strategy, generally associated with the prevention of oxidative stress and inflammatory response. This study evaluates the neuroprotective role of the Plinia trunciflora fruit extract (PTE) in neonatal rats submitted to experimental HI. The HI insult provoked a marked increase in the lipoperoxidation levels and glutathione peroxidase (GPx) activity, accompanied by a decrease in the brain concentration of glutathione (GSH). Interestingly, PTE was able to prevent most of the HI-induced pro-oxidant effects. It was also observed that HI increased the levels of interleukin-1β in the hippocampus, and that PTE-treatment prevented this effect. Furthermore, PTE was able to prevent neuronal loss and astrocyte reactivity induced by HI, as demonstrated by NeuN and GFAP staining, respectively. PTE also attenuated the anxiety-like behavior and prevented the spatial memory impairment caused by HI. Finally, PTE prevented neural tissue loss in the brain hemisphere, the hippocampus, cerebral cortex, and the striatum ipsilateral to the HI. Taken together our results provide good evidence that the PTE extract has the potential to be investigated as an adjunctive therapy in the treatment of brain insult caused by neonatal hypoxia–ischemia.

Cause of Death in Neonates With Neurological Insults in the Neonatal Intensive Care Unit: Insights From A MITS Pilot Study

Background

Minimally invasive tissue sampling (MITS) of organs has been used as an alternative to complete diagnostic autopsy in countries where refusal for autopsy in newborns is common for sociocultural reasons. There is a paucity of literature regarding the diagnostic utility of MITS of the brain after death in neonates with neurological insults, especially in India.

Methods

This was a prospective, preliminary single-center tertiary care hospital study in India, focused specifically on MITS of the brain after neonatal death as a diagnostic tool to identify the various neurological insults. All neonatal deaths with neurological symptoms occurring within the first 30 days of life were enrolled, irrespective of the suspected clinical diagnosis.

Results

Sixteen neonates were enrolled after death for MITS of the brain, performed for diagnostic purposes, during the study period from February 2020 to March 2021. Their gestational ages ranged from 26 to 38 weeks. All neonates had either a history of seizures and/or respiratory distress or clinical evidence of sepsis and were on ventilator support. Histopathology in all 16 neonates showed evidence of anoxia, with or without reactive astrogliosis or microgliosis. In 5 neonates with cranial ultrasound evidence of brain hemorrhage, MITS of the brain showed intraventricular hemorrhage, subdural hemorrhage, or intraparenchymal white matter microhemorrhages. Premortem blood culture–proven sepsis was seen in 9 neonates. In all cases (100%), MITS had a good diagnostic yield and was useful to establish the neurological insult in the brain.

Conclusions

MITS of the brain provides an accurate and adequate diagnosis and can be an alternative to complete diagnostic autopsy for establishing the cause of death due to neurological insults, especially in low-resource settings where obtaining consent for more invasive procedure is often challenging.

A new Hypoxic Ischemic Encephalopathy model in neonatal rats

BACKGROUND

Hypoxic-Ischemic Encephalopathy (HIE) occurs when an infant's brain does not receive adequate blood and oxygen supply, resulting in ischemic and hypoxic brain damage during delivery. Currently, supportive care and hypothermia have been the standard treatment for HIE. However, there are still a 20% mortality and most of the survivors are associated with significant neurodevelopmental disability. HIE animal model was first established by Vannucci et al., in 1981, and has been used extensively to explore the mechanisms of brain damage and its potential treatment. The Vannucci model involves the unilateral common carotid artery occlusion followed by 90 min hypoxia (8% oxygen). The purpose of this study is to define and validate a modified HIE model which mimics closely that of the human neonatal HIE.

METHOD

The classic Vannucci HIE model occludes one common carotid artery followed by 90 min hypoxia. In the new model, common carotid arteries were occluded bilaterally followed by breathing 8% oxygen in a hypoxic chamber for 90, 60 and 30 min, followed by the release of the common carotid artery ligatures, mimicking a reperfusion.

RESULT

We studied 110 neonatal rats in detail, following the modified in comparison with the classical Vannucci models. The classical Vannucci model has a consistent surgical mortality of 18% and the new modified models have a 20%-46%. While mortality depended on the duration of hypoxia, fifty-two animals survived for behavioral assessments and standard histology. The modified HIE model with 60 min of transient carotid occlusion is associated with a moderate brain damage, and has a 30% surgical mortality. This modified experimental model is regarded closer to the human situation than the classical Vannucci model.

Brief Report: Pregnancy, Birth and Infant Feeding Practices: A Survey-Based Investigation into Risk Factors for Autism Spectrum Disorder

A succession of interconnected environmental factors is believed to contribute substantially to the development of autism spectrum disorder (ASD). This exploratory study therefore aims to identify potential risk factors for ASD that are associated with pregnancy, birth and infant feeding. Demographic and health-related data on children aged 3-13 years (N = 4306) was collected through an online survey completed by biological mothers. A fitted logistic regression model identified advanced maternal age, prenatal bleeding, pre-eclampsia, perinatal pethidine usage, foetal distress before birth and male sex of child as associated with an increased risk of ASD, whereas longer gestational duration demonstrated a protective effect. These findings highlight potential risk factors and predictor interrelationships which may contribute to overall ASD risk.

Genetic Polymorphisms, Gene-Gene Interactions and Neurologic Sequelae at Two Years Follow-Up in Newborns with Hypoxic-Ischemic Encephalopathy Treated with Hypothermia

Inflammation and oxidative stress after hypoxic-ischemic brain injury may be modified by genetic variability in addition to therapeutic hypothermia. The aim of our study was to evaluate the association between the polymorphisms in genes of antioxidant and inflammatory pathways in newborns treated with therapeutic hypothermia and the development of epilepsy or CP at two years follow-up. The DNA of 55 subjects was isolated from buccal swabs. Genotyping using competitive allele-specific PCR was performed for polymorphisms in antioxidant (SOD2 rs4880, CAT rs1001179, GPX1 rs1050450) and inflammatory (NLRP3 rs35829419, CARD8 rs2043211, IL1B rs1143623, IL1B rs16944, IL1B rs10716 76, TNF rs1800629) pathways. Polymorphic CARD8 rs2043211 T allele was less frequent in patients with epilepsy, but the association was not statistically significant. The interaction between CARD8 rs2043211 and IL1B rs16944 was associated with epilepsy after HIE: CARD8 rs2043211 was associated with lower epilepsy risk, but only in carriers of two normal IL1B rs16944 alleles (OR_adj = 0.03 95% CI = 0.00–0.55; p_adj = 0.019). Additionally, IL1B rs16944 was associated with higher epilepsy risk only in carriers of at least one polymorphic CARD8 rs2043211 (OR_adj = 13.33 95% CI = 1.07–166.37; p_adj = 0.044). Our results suggest that gene–gene interaction in inflammation pathways might contribute to the severity of brain injury in newborns with HIE treated with therapeutic hypothermia.

Mitochondrial dysfunction in perinatal asphyxia: role in pathogenesis and potential therapeutic interventions

Perinatal asphyxia (PA)-induced brain injury may present as hypoxic-ischemic encephalopathy in the neonatal period, and long-term sequelae such as spastic motor deficits, intellectual disability, seizure disorders and learning disabilities. The brain injury is secondary to both the hypoxic-ischemic event and oxygenation-reperfusion following resuscitation. Following PA, a time-dependent progression of neuronal insult takes place in terms of transition of cell death from necrosis to apoptosis. This transition is the result of time-dependent progression of pathomechanisms which involve excitotoxicity, oxidative stress, and ultimately mitochondrial dysfunction in developing brain. More precisely mitochondrial respiration is suppressed and calcium signalling is dysregulated. Consequently, Bax-dependent mitochondrial permeabilization occurs leading to release of cytochrome c and activation of caspases leading to transition of cell death in developing brain. The therapeutic window lies within this transition process. At present, therapeutic hypothermia (TH) is the only clinical treatment available for treating moderate as well as severe asphyxia in new-born as it attenuates secondary loss of high-energy phosphates (ATP) (Solevåg et al. in Free Radic Biol Med 142:113-122, 2019; Gunn et al. in Pediatr Res 81:202-209, 2017), improving both short- and long-term outcomes. Mitoprotective therapies can offer a new avenue of intervention alone or in combination with therapeutic hypothermia for babies with birth asphyxia. This review will explore these mitochondrial pathways, and finally will summarize past and current efforts in targeting these pathways after PA, as a means of identifying new avenues of therapeutic intervention.

Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures

Epilepsy is associated with a multitude of acquired or genetic neurological disorders characterized by a predisposition to spontaneous recurrent seizures. An estimated 15 million patients worldwide have ongoing seizures despite optimal management and are classified as having refractory epilepsy. Early-life seizures like those caused by perinatal hypoxic ischemic encephalopathy (HIE) remain a clinical challenge because although transient, they are difficult to treat and associated with poor neurological outcomes. Pediatric epilepsy syndromes are consistently associated with intellectual disability and neurocognitive comorbidities. HIE and arterial ischemic stroke are the most common causes of seizures in term neonates and account for 7.5-20% of neonatal seizures. Standard first-line treatments such as phenobarbital (PB) and phenytoin fail to curb seizures in ~50% of neonates. In the long-term, HIE can result in hippocampal sclerosis and temporal lobe epilepsy (TLE), which is the most common adult epilepsy, ~30% of which is associated with refractory seizures. For patients with refractory TLE seizures, a viable option is the surgical resection of the epileptic foci. Novel insights gained from investigating the developmental role of Cl- cotransporter function have helped to elucidate some of the mechanisms underlying the emergence of refractory seizures in both HIE and TLE. KCC2 as the chief Cl- extruder in neurons is critical for enabling strong hyperpolarizing synaptic inhibition in the brain and has been implicated in the pathophysiology underlying both conditions. More recently, KCC2 function has become a novel therapeutic target to combat refractory seizures.

Anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor encephalitis: A case report

INTRODUCTION

: Anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) is a subtype of glutamate receptor that mediates most of the fast excitatory neurotransmission in the brain. Anti-AMPAR encephalitis is an autoimmune-mediated neurological disorder, frequently accompanied by the presence of neoplasms, comprising a spectrum of paraneoplastic syndrome.

PATIENT CONCERNS

A 56-year-old man was admitted for deterioration in memory and aberrant psychological behaviors, which lasted for at least 20 days.

DIAGNOSIS

The patient was diagnosed as anti-AMPAR encephalitis and 4 months later, he was diagnosed with small cell lung cancer.

INTERVENTIONS

Once diagnosis for anti-AMPAR encephalitis was confirmed, methylprednisolone was prescribed with initial dose 500 mg/d for 14 days until the patient returned to pre-illness state. Then he was discharged with oral treatment with corticosteroids. Following the diagnosis of small cell lung cancer, he received 5 rounds of chemotherapy, including carboplatin and etoposide.

OUTCOMES

After taken the prescription of Methylprednisolone for anti-AMPAR encephalitis, he returned to pre-illness state and was discharged. In April 21, 2017, after symptoms of respiratory system showed up, he was diagnosed with small cell lung cancer and he eventually died of respiratory failure.

CONCLUSION

Though progress has been made in recent years in diagnosis and treatment for autoimmune encephalitis, it is challenging to diagnose due to the similarity in clinical findings with other autoimmune or infectious encephalitis. In addition, it is necessary for these patients to regularly have tumor screening, considering AMPAR antibody encephalitis is closely associated with neoplasm, and the incidence of paraneoplastic syndrome is 63% to 70%.

Metabolic adaptations to hypoxia in the neonatal mouse forebrain can occur independently of the transporters SLC7A5 and SLC3A2

Neonatal encephalopathy due to hypoxia-ischemia is associated with adverse neurodevelopmental effects. The involvement of branched chain amino acids (BCAAs) in this is largely unexplored. Transport of BCAAs at the plasma membrane is facilitated by SLC7A5/SLC3A2, which increase with hypoxia. We hypothesized that hypoxia would alter BCAA transport and metabolism in the neonatal brain. We investigated this using an organotypic forebrain slice culture model with, the SLC7A5/SLC3A2 inhibitor, 2-Amino-2-norbornanecarboxylic acid (BCH) under normoxic or hypoxic conditions. We subsequently analysed the metabolome and candidate gene expression. Hypoxia was associated with increased expression of SLC7A5 and SLC3A2 and an increased tissue abundance of BCAAs. Incubation of slices with 13C-leucine confirmed that this was due to increased cellular uptake. BCH had little effect on metabolite abundance under normoxic or hypoxic conditions. This suggests hypoxia drives increased cellular uptake of BCAAs in the neonatal mouse forebrain, and membrane mediated transport through SLC7A5 and SLC3A2 is not essential for this process. This indicates mechanisms exist to generate the compounds required to maintain essential metabolism in the absence of external nutrient supply. Moreover, excess BCAAs have been associated with developmental delay, providing an unexplored mechanism of hypoxia mediated pathogenesis in the developing forebrain.

Moderately Inducing Autophagy Reduces Tertiary Brain Injury after Perinatal Hypoxia-Ischemia

Recent studies of cerebral hypoxia-ischemia (HI) have highlighted slowly progressive neurodegeneration whose mechanisms remain elusive, but if blocked, could considerably improve long-term neurological function. We previously established that the cytokine transforming growth factor (TGF)β1 is highly elevated following HI and that delivering an antagonist for TGFβ receptor activin-like kinase 5 (ALK5)-SB505124-three days after injury in a rat model of moderate pre-term HI significantly preserved the structural integrity of the thalamus and hippocampus as well as neurological functions associated with those brain structures. To elucidate the mechanism whereby ALK5 inhibition reduces cell death, we assessed levels of autophagy markers in neurons and found that SB505124 increased numbers of autophagosomes and levels of lipidated light chain 3 (LC3), a key protein known to mediate autophagy. However, those studies did not determine whether (1) SB was acting directly on the CNS and (2) whether directly inducing autophagy could decrease cell death and improve outcome. Here we show that administering an ALK5 antagonist three days after HI reduced actively apoptotic cells by ~90% when assessed one week after injury. Ex vivo studies using the lysosomal inhibitor chloroquine confirmed that SB505124 enhanced autophagy flux in the injured hemisphere, with a significant accumulation of the autophagic proteins LC3 and p62 in SB505124 + chloroquine treated brain slices. We independently activated autophagy using the stimulatory peptide Tat-Beclin1 to determine if enhanced autophagy is directly responsible for improved outcomes. Administering Tat-Beclin1 starting three days after injury preserved the structural integrity of the hippocampus and thalamus with improved sensorimotor function. These data support the conclusion that intervening at this phase of injury represents a window of opportunity where stimulating autophagy is beneficial.

Cell-based treatment for perinatal hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is a major cause of acute neonatal brain injury and can lead to disabling long-term neurological complications. Treatment for HIE is limited to supportive care and hypothermia within 6 h injury which is reserved for full-term infants. Preclinical studies suggest the potential for cell-based therapies as effective treatments for HIE. Some clinical trials using umbilical cord blood cells, placenta-derived stem cells, mesenchymal stem cells (MSCs), and others have yielded promising results though more studies are needed to optimize protocols and multi-center trials are needed to prove safety and efficacy. To date, the therapeutic effects of most cell-based therapies are hypothesized to stem from the bystander effect of donor cells. Transplantation of stem cells attenuate the aberrant inflammation cascade following HIE and provide a more ideal environment for endogenous neurogenesis and repair. Recently, a subset of MSCs, the multilineage-differentiating stress-enduring (Muse) cells have shown to treat HIE and other models of neurologic diseases by replacing dead or ischemic cells and have reached clinical trials. In this review, we examine the different cell sources used in clinical trials and evaluate the underlying mechanism behind their therapeutic effects. Three databases–PubMed, Web of Science, and ClinicalTrials.gov–were used to review preclinical and clinical experimental treatments for HIE.

Caffeine and Its Neuroprotective Role in Ischemic Events: A Mechanism Dependent on Adenosine Receptors

Ischemia is characterized by a transient, insufficient, or permanent interruption of blood flow to a tissue, which leads to an inadequate glucose and oxygen supply. The nervous tissue is highly active, and it closely depends on glucose and oxygen to satisfy its metabolic demand. Therefore, ischemic conditions promote cell death and lead to a secondary wave of cell damage that progressively spreads to the neighborhood areas, called penumbra. Brain ischemia is one of the main causes of deaths and summed with retinal ischemia comprises one of the principal reasons of disability. Although several studies have been performed to investigate the mechanisms of damage to find protective/preventive interventions, an effective treatment does not exist yet. Adenosine is a well-described neuromodulator in the central nervous system (CNS), and acts through four subtypes of G-protein-coupled receptors. Adenosine receptors, especially A₁ and A_2A receptors, are the main targets of caffeine in daily consumption doses. Accordingly, caffeine has been greatly studied in the context of CNS pathologies. In fact, adenosine system, as well as caffeine, is involved in neuroprotection effects in different pathological situations. Therefore, the present review focuses on the role of adenosine/caffeine in CNS, brain and retina, ischemic events.

The effect of magnetic guiding BMSCs on hypoxic-ischemic brain damage via magnetic resonance imaging evaluation

Hypoxic-ischemic brain damage (HIBD) is a critical disease in pediatric neurosurgery with high mortality rate and frequently leads to neurological sequelae. The role of bone marrow mesenchymal stem cells (BMSCs) in neuroprotection has been recognized. However, using the imaging methods to dynamically assess the neuroprotective effects of BMSCs is rarely reported. In this study, BMSCs were isolated, cultured and identified. Flow cytometry assay had shown the specific surface molecular markers of BMSCs, which indicated that the cultivated cells were purified BMSCs. The results demonstrated that CD29 and CD90 were highly expressed, whilst CD45 and CD11b were negatively expressed. Further, BMSCs were transplanted into Sprague Dawley (SD) rats established HIBD via three ways, including lateral ventricle (LV) injection, tail vein (TV) injection, and LV injection with magnetic guiding. Magnetic resonance imaging (MRI) was used to monitor and assess the treatment effect of super paramagnetic iron oxide (SPIO)-labeled BMSCs. The mean kurtosis (MK) values from diffusion kurtosis imaging (DKI) exhibited the significant differences. It was found that the MK value of HIBD group increased compared with that in Sham. At the meantime, the MK values of LV + HIBD, TV + HIBD and Magnetic+LV + HIBD groups decreased compared with that in HIBD group. Among these, the MK value reduced most significantly in Magnetic+LV + HIBD group. MRI illustrated that the treatment effect of Magnetic+LV + HIBD group was best. In addition, HE staining and TUNEL assay measured the pathological changes and apoptosis of brain tissues, which further verified the MRI results. All data suggest that magnetic guiding BMSCs, a targeted delivery way, is a new strategic theory for HIBD treatment. The DKI technology of MRI can dynamically evaluate the neuroprotective effects of transplanted BMSCs in HIBD.

Neuroprotective Treatment of Postanoxic Encephalopathy: A Review of Clinical Evidence

Postanoxic encephalopathy is the key determinant of death or disability after successful cardiopulmonary resuscitation. Animal studies have provided proof-of-principle evidence of efficacy of divergent classes of neuroprotective treatments to promote brain recovery. However, apart from targeted temperature management (TTM), neuroprotective treatments are not included in current care of patients with postanoxic encephalopathy after cardiac arrest. We aimed to review the clinical evidence of efficacy of neuroprotective strategies to improve recovery of comatose patients after cardiac arrest and to propose future directions. We performed a systematic search of the literature to identify prospective, comparative clinical trials on interventions to improve neurological outcome of comatose patients after cardiac arrest. We included 53 studies on 21 interventions. None showed unequivocal benefit. TTM at 33 or 36°C and adrenaline (epinephrine) are studied most, followed by xenon, erythropoietin, and calcium antagonists. Lack of efficacy is associated with heterogeneity of patient groups and limited specificity of outcome measures. Ongoing and future trials will benefit from systematic collection of measures of baseline encephalopathy and sufficiently powered predefined subgroup analyses. Outcome measurement should include comprehensive neuropsychological follow-up, to show treatment effects that are not detectable by gross measures of functional recovery. To enhance translation from animal models to patients, studies under experimental conditions should adhere to strict methodological and publication guidelines.

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.

CARD8 and IL1B Polymorphisms Influence MRI Brain Patterns in Newborns with Hypoxic-Ischemic Encephalopathy Treated with Hypothermia

Inflammation and oxidative stress are recognized as important contributors of brain injury in newborns due to a perinatal hypoxic-ischemic (HI) insult. Genetic variability in these pathways could influence the response to HI and the outcome of brain injury. The aim of our study was to evaluate the impact of common single-nucleotide polymorphisms in the genes involved in inflammation and response to oxidative stress on brain injury in newborns after perinatal HI insult based on the severity and pattern of magnetic resonance imaging (MRI) findings. The DNA of 44 subjects was isolated from buccal swabs. Genotyping was performed for NLRP3 rs35829419, CARD8 rs2043211, IL1B rs16944, IL1B rs1143623, IL1B rs1071676, TNF rs1800629, CAT rs1001179, SOD2 rs4880, and GPX1 rs1050450. Polymorphism in CARD8 was found to be protective against HI brain injury detected by MRI overall findings. Polymorphisms in IL1B were associated with posterior limb of internal capsule, basal ganglia, and white matter brain patterns determined by MRI. Our results suggest a possible association between genetic variability in inflammation- and antioxidant-related pathways and the severity of brain injury after HI insult in newborns.

Prenatal Hypoxia Induces Premature Aging Accompanied by Impaired Function of the Glutamatergic System in Rat Hippocampus

Prenatal hypoxia is among leading causes of progressive brain pathologies in postnatal life. This study aimed to analyze the characteristics of the hippocampal glutamatergic system and behavior of rats in early (2 weeks), adult (3 months) and advanced (18 months) postnatal ontogenesis after exposure to prenatal severe hypoxia (PSH, 180 Torr, 5% O2, 3 h) during the critical period in the formation of the hippocampus (days 14-16 of gestation). We have shown an age-dependent progressive decrease in the hippocampal glutamate levels, a decrease of the neuronal cell number in the CA1 hippocampal region, as well as impairment of spatial long-term memory in the Morris water navigation task. The gradual decrease of glutamate was accompanied by decreased expression of the genes that mediate glutamate metabolism and recycling in the hippocampus. That deficiency apparently correlated with an increase of the metabotropic glutamate receptor type 1 (mGluR1) and synaptophysin expression. Generation of the lipid peroxidation products in the hippocampus of adult rats subjected to prenatal severe hypoxia (PSH rats) was not increased compared to the control animals when tested in a model of glutamate excitotoxicity induced by severe hypoxia. This demonstrates that excessive glutamate sensitivity in PSH rats does not compensate for glutamate deficiency. Our results show a significant contribution of the glutamate system dysfunction to age-associated decrease of this mediator, cognitive decline, and early neuronal loss in PSH rats.

Neuroprotective Effects of Growth Hormone (GH) and Insulin-Like Growth Factor Type 1 (IGF-1) after Hypoxic-Ischemic Injury in Chicken Cerebellar Cell Cultures

It has been reported that growth hormone (GH) and insulin-like growth factor 1 (IGF-1) exert protective and regenerative actions in response to neural damage. It is also known that these peptides are expressed locally in nervous tissues. When the central nervous system (CNS) is exposed to hypoxia-ischemia (HI), both GH and IGF-1 are upregulated in several brain areas. In this study, we explored the neuroprotective effects of GH and IGF-1 administration as well as the involvement of these endogenously expressed hormones in embryonic chicken cerebellar cell cultures exposed to an acute HI injury. To induce neural damage, primary cultures were first incubated under hypoxic-ischemic (<5% O₂, 1g/L glucose) conditions for 12 h (HI), and then incubated under normal oxygenation and glucose conditions (HI + Ox) for another 24 h. GH and IGF-1 were added either during or after HI, and their effect upon cell viability, apoptosis, or necrosis was evaluated. In comparison with normal controls (Nx, 100%), a significant decrease of cell viability (54.1 ± 2.1%) and substantial increases in caspase-3 activity (178.6 ± 8.7%) and LDH release (538.7 ± 87.8%) were observed in the HI + Ox group. On the other hand, both GH and IGF-1 treatments after injury (HI + Ox) significantly increased cell viability (77.2 ± 4.3% and 72.3 ± 3.9%, respectively) and decreased both caspase-3 activity (118.2 ± 3.8% and 127.5 ± 6.6%, respectively) and LDH release (180.3 ± 21.8% and 261.6 ± 33.9%, respectively). Incubation under HI + Ox conditions provoked an important increase in the local expression of GH (3.2-fold) and IGF-1 (2.5-fold) mRNAs. However, GH gene silencing with a specific small-interfering RNAs (siRNAs) decreased both GH and IGF-1 mRNA expression (1.7-fold and 0.9-fold, respectively) in the HI + Ox group, indicating that GH regulates IGF-1 expression under these incubation conditions. In addition, GH knockdown significantly reduced cell viability (35.9 ± 2.1%) and substantially increased necrosis, as determined by LDH release (1011 ± 276.6%). In contrast, treatments with GH and IGF-1 stimulated a partial recovery of cell viability (45.2 ± 3.7% and 53.7 ± 3.2%) and significantly diminished the release of LDH (320.1 ± 25.4% and 421.7 ± 62.2%), respectively. Our results show that GH, either exogenously administered and/or locally expressed, can act as a neuroprotective factor in response to hypoxic-ischemic injury, and that this effect may be mediated, at least partially, through IGF-1 expression.

Clinical significance of electroencephalography power spectrum density and functional connection analysis in neonates with hypoxic-ischemic encephalopathy

OBJECTIVE

To investigate the effects of electroencephalography (EEG) power and functional connectivity analysis on cerebral cortex function in neonates with hypoxic-ischemic encephalopathy (HIE), and to identify the neurobiological indicators of neural development in HIE.

METHODS

We recruited 20 mild HIE neonates, 15 moderate HIE neonates, and 30 controls. EEG was performed about 72 hr after birth. The power spectral density (PSD) and imaginary part of coherency (ICOH) were analyzed. Gesell developmental schedule (GDS) was used to evaluate the neural development in the mild and moderate HIE groups at 1 year of age, and the correlation between the quantitative EEG results and the state of neural development was analyzed.

RESULTS

Compared with the controls, FP1, FP2, C3, C4, Fz, Cz, Pz , F3, and P4 of moderate HIE neonates showed that the PSD of theta, alpha and beta bands decreased significantly. In terms of the mean whole-brain PSD, the moderate HIE group showed a significant decrease in all frequency bands. ICOH of the moderate HIE group showed that functional connectivity was significantly less than that in the controls mainly in the delta band, and the functional connectivity of the delta, theta, alpha1, and alpha2 bands was markedly reduced compared with the mild HIE. GDS test at 1 year old showed that two infants in the moderate HIE group had suspected neurological delay in gross motor and language. The developmental quotient(DQ) of gross motor, language, and personal-social ability in the moderate HIE group were significantly lower than in the mild HIE group. And there was a significant positive correlation between PSD in each EEG frequency band and GDS score in the moderate HIE group.

CONCLUSION

PSD and ICOH can be used to evaluate brain function. PSD can detect the delayed neurological development in infants with moderate HIE, and can be a neurobiomarker of brain development in HIE.

Study on serum Tau protein level and neurodevelopmental outcome of placental abruption with neonatal hypoxic-ischemic encephalopathy

Objective: The aim of this study was to explore differences in serum Tau protein levels and neurodevelopmental prognoses of placental abruption or umbilical cord around neck with hypoxic-ischemic encephalopathy (HIE).Methods: Forty neonates with moderate/severe HIE divided into placental abruption with HIE group (placental abruption with hypoxic-ischemic encephalopathy (PA-HIE) group) (n = 18) and umbilical cord around the neck with HIE group (umbilical cord around the neck with hypoxic-ischemic encephalopathy (UCAN-HIE) group) (n = 22). Healthy term newborns comprised the control group (n = 35). Serum Tau protein levels were measured using an enzyme-linked immunosorbent assay 24 hours (3.50 hours [1.00-24.00]) after birth. Neurodevelopment outcomes were assessed based on the Gesell Developmental Scale at 9 months of age.Results: Serum Tau protein levels were significantly higher in 40 cases (1013 pg/ml [538.04-1190.42]) than in the control group (106.41 pg/ml [64.55-154.71], p = .0001). Serum Tau protein levels in the PA-HIE group (1024.46 pg/ml [657.88-1190.42]) were significantly higher than those in the UCAN-HIE group (892.78 pg/ml [538.04-1179.50], p = .0149). The development quotient score in the PA-HIE group (67.0 [47.0-90.0]) was significantly lower than that in the UCAN-HIE group (81.5 [52.6-100.0]) (p = .0028). The component ratio of neurodevelopmental retardation in the PA-HIE group (44.45%) was significantly higher than that in the UCAN-HIE group (22.73%) (X² = 13.3138, p = .0013).Conclusions: Compared with the UCAN-HIE group, the serum Tau protein level and the component ratio of neurodevelopmental retardation were significantly higher in the PA-HIE group.

A pictorial review of the pathophysiology and classification of the magnetic resonance imaging patterns of perinatal term hypoxic ischemic brain injury - What the radiologist needs to know…

This article provides a correlation of the pathophysiology and magnetic resonance imaging (MRI) patterns identified on imaging of children with hypoxic ischemic brain injury (HIBI). The purpose of this pictorial review is to empower the reading radiologist with a simplified classification of the patterns of cerebral injury matched to images of patients demonstrating each subtype. A background narrative literature review was undertaken of the regional, continental and international databases looking at specific patterns of cerebral injury related to perinatal HIBI. In addition, a database of MRI studies accumulated over a decade (including a total of 314 studies) was analysed and subclassified into the various patterns of cerebral injury. Selected cases were annotated to highlight the areas involved and for ease of identification of the affected substrate in daily practice.

KEYWORDS

Hypoxic ischemic encephalopathy; Magnetic resonance imaging; Acute profound; Partial prolonged; Hypoxic ischemic brain injury; Ulegyria; Multicystic; Encephalopathy.

The Function of the NMDA Receptor in Hypoxic-Ischemic Encephalopathy

Hypoxic-ischemic encephalopathy (HIE) is one of the main forms of neonatal brain injury which could lead to neonatal disability or even cause neonatal death. Therefore, HIE strongly affects the health of newborns and brings heavy burden to the family and society. It has been well studied that N-methyl-D-aspartate (NMDA) receptors are involved in the excitotoxicity induced by hypoxia ischemia in adult brain. Recently, it has been shown that the NMDA receptor also plays important roles in HIE. In the present review, we made a summary of the molecular mechanism of NMDA receptor in the pathological process of HIE, focusing on the distinct role of GluN2A- and GluN2B-containing NMDA receptor subtypes and aiming to provide some insights into the clinical treatment and drug development of HIE.

Evaluation of Magnetic Resonance (MR) Findings in Patients with Refractory Epilepsy

Objectives:

Epilepsy is characterized as a tendency towards recurrent seizures and it is a significant health problem in the world and one of the most common severe neurologic disorders among children. This study aims to evaluate the outcome of magnetic resonance imaging in determining the etiology in patients with refractory epilepsy and to reveal pathologies that may have the potential to be treated with methods, such as epileptic surgery.

Methods:

Data were obtained from the patient files of the patients diagnosed with epilepsy and monitored for at least two years between 01.01.2009-12.31.2012 in the Uludag Faculty of Medicine, the Division of the Pediatric Neurology. File records of the patients, age, sex and MRI findings of the patients were recorded.

Results:

One hundred twenty were girls (49%) and 125 were male (51%) of the cases. The age range ranged from 1 to 18 years and the median value was 8.3 (1-18) years. One hundred twenty of the 245 patients who met the diagnostic criteria for resistant epilepsy was found as well controlled. In patients with resistant epilepsy, the findings of these two groups of patients were compared concerning MR findings. Among all patients, 154 (62.8%) patients were found to have MR pathology. Of these patients, 83 (53.9%) were in the resistant group and 71 (46.1%) were in the well-controlled group. There was no significant difference in the presence of MR findings between the two groups (p=0.354). The highest incidence (24.8%) of the encephalomalacia in patients in the resistant group may explain the association of perinatal hypoxia with resistance development.

Conclusion:

If patients with epilepsy can be predicted early in the disease, which group of the patients will not respond well to medical treatment; unlike other patients, different treatment modalities, such as antiepileptic use, vagal nerve stimulation, ketogenic diet and epilepsy surgery, can be applied to this group of the patients. We think that clinicians can guide the planning of treatment of the MR findings.

Neuroprotection of hypoxic/ischemic preconditioning in neonatal brain with hypoxic-ischemic injury

The neonatal brain is susceptible to hypoxic-ischemic injury due to its developmental characteristics. Hypoxia-ischemia means a decreased perfusion of oxygen and glucose, which can lead to severe encephalopathy. Although early initiation of therapeutic hypothermia was reported to provide neuroprotection for infants after HI, hypothermia administered alone after the acute insult cannot reverse the severe damage that already has occurred or improve the prognosis of severe hypoxic-ischemic encephalopathy. Therefore, exploring new protective mechanisms for treating hypoxic-ischemic brain damage are imperative. Until now, many studies reported the neuroprotective mechanisms of hypoxic/ischemic preconditioning in protecting the hypoxic-ischemic newborn brains. After hypoxia and ischemia, hypoxia-inducible factor signaling pathway is involved in the transcriptional regulation of many genes and is also play a number of different roles in protecting brains during hypoxic/ischemic preconditioning. Hypoxic/ischemic preconditioning could protect neonatal brain by several mechanisms, including vascular regulation, anti-apoptosis, anti-oxidation, suppression of excitotoxicity, immune regulation, hormone levels regulation, and promote cell proliferation. This review focused on the protective mechanisms underlying hypoxic/ischemic preconditioning for neonatal brain after hypoxia-ischemia and emphasized on the important roles of hypoxia inducible factor 1 signaling pathway.

Temporally Altered miRNA Expression in a Piglet Model of Hypoxic Ischemic Brain Injury

Hypoxic ischemic encephalopathy (HIE) is the most frequent cause of acquired infant brain injury. Early, clinically relevant biomarkers are required to allow timely application of therapeutic interventions. We previously reported early alterations in several microRNAs (miRNA) in umbilical cord blood at birth in infants with HIE. However, the exact timing of these alterations is unknown. Here, we report serial changes in six circulating, cross-species/bridging biomarkers in a clinically relevant porcine model of neonatal HIE with functional analysis. Six miRNAs—miR-374a, miR-181b, miR-181a, miR-151a, miR-148a and miR-128—were significantly and rapidly upregulated 1-h post-HI. Changes in miR-374a, miR-181b and miR-181a appeared specific to moderate-severe HI. Histopathological injury and five miRNAs displayed positive correlations and were predictive of MRS Lac/Cr ratios. Bioinformatic analysis identified that components of the bone morphogenic protein (BMP) family may be targets of miR-181a. Inhibition of miR-181a increased neurite length in both SH-SY5Y cells at 1 DIV (days in vitro) and in primary cultures of rat neuronal midbrain at 3 DIV. In agreement, inhibition of miR-181a increased expression of BMPR2 in differentiating SH-SY5Y cells. These miRNAs may therefore act as early biomarkers of HIE, thereby allowing for rapid diagnosis and timely therapeutic intervention and may regulate expression of signalling pathways vital to neuronal survival.

Microglia enhances proliferation of neural progenitor cells in an in vitro model of hypoxic-ischemic injury

Microglial cells are the primary immune cells in the central nervous system. In the mature brain, microglia perform functions that include eliminating pathogens and clearing dead/dying cells and cellular debris through phagocytosis. In the immature brain, microglia perform functions that include synapse development and the regulation of cell production through extensive contact with and phagocytosis of neural progenitor cells (NPCs). However, the functional role of microglia in the proliferation and differentiation of NPCs under hypoxic-ischemic (HI) injury is not clear. Here, we tested the hypothesis that microglia enhance NPCs proliferation following HI insult. Primary NPCs cultures were divided into four treatment groups: 1) normoxic NPCs (NN); 2) normoxic NPCs cocultured with microglia (NN+M); 3) hypoxic NPCs (HN); and 4) hypoxic NPCs cocultured with microglia (HN+M). Hypoxic-ischemic injury was induced by pretreatment of the cell cultures with 100 µM deferoxamine mesylate (DFO). NPCs treated with 100 µM DFO (HN groups) for 24 hours had significantly increased expression of hypoxia-inducible factor 1 alpha (HIF-1α), a marker of hypoxic cells. Cell number, protein expression, mitosis, and cell cycle phase were examined, and the data were compared between the four groups. We found that the number of cells expressing the NPCs marker Sox2 increased significantly in the HN+M group and that the number of PH3-positive cells increased in the HN+M group; flow cytometry analysis showed a significant increase in the percentage of cells in the G2/M phase in the HN+M group. In summary, these results support the concept that microglia enhance the survival of NPCs under HI injury by increasing NPCs proliferation, survival, and differentiation. These results further suggest that microglia may induce neuroprotective effects after hypoxic injury that can be explored to develop novel therapeutic strategies for the treatment of HI injury in the immature brain.

Long-Term Effects of Hypoxia-Reoxygenation on Thioredoxins in Rat Central Nervous System

BACKGROUND

Oxidative stress induced by the oxidative pathway dysregulation following ischemia/ reperfusion has been proposed as an important cause of neuronal death and brain damage. The proteins of the thioredoxin (Trx) family are crucial mediators of protein function regulating the intracellular hydrogen peroxide levels and redox-sensitive post-translational protein changes.

AIM

To analyze the expression and distribution of fourteen members of the Trx family, potentially essential for the regeneration upon long-term brain damage, in a perinatal hypoxia-ischemia rat model induced by common carotid artery ligation.

METHODS

The right common carotid artery (CCA) was exposed by an incision on the right side of the neck, isolated from nerve and vein, and permanently ligated. Sham-surgery rats underwent right CCA surgical exposure but no ligation. Euthanasia was administered to all rats at 30, 60, and 90 days of age. Protein expression and distribution of fourteen members of the Trx family and related proteins (Grx1, Grx2, Grx3, Grx5, Prx1, Prx2, Prx3, Prx4, Prx5, Prx6, Trx1, Trx2, TrxR1, TrxR2) was examined in the most hypoxia susceptible rat brain areas, namely, cerebellum, corpus striatum, and the hippocampus.

RESULTS

The thioredoxin proteins displayed a complex, cell-type, and tissue-specific expression pattern following ischemia/reperfusion. Even 60 days after ischemia/reperfusion, Western blot analysis showed a persistent expression of Trx1 and Grx2 in several brain areas.

CONCLUSION

The Trx family of proteins might contribute to long-term survival and recovery supporting their therapeutic use to curtail ischemic brain oxidative damage following an ischemia/reperfusion insult. Characterization of ischemia/reperfusion oxidative brain damage and analysis of the involved mechanisms are required to understand the underneath processes triggered by ischemia/reperfusion and to what extent and in what way thioredoxins contribute to recovery from brain hypoxic stress.

Expression profile of circular RNAs in the peripheral blood of neonates with hypoxic‑ischemic encephalopathy

Circular RNAs (circRNAs) are a class of non-coding RNAs that participate in various biological processes. However, the function of circRNAs in neonatal hypoxic‑ischemic encephalopathy (HIE) is not fully understood. In the present study, the differentially expressed circRNAs in the peripheral blood of neonates with HIE and control samples were characterized by a microarray assay. A total of 456 circRNAs were significantly differentially expressed in the peripheral blood of neonates with HIE, with 250 upregulated and 206 downregulated circRNAs in HIE compared with the control samples. Reverse transcription‑quantitative PCR was used to investigate specific circRNAs. Gene Ontology, and Kyoto Encyclopedia of Genes and Genomes pathway analyses were used to determine the function of the parent genes of the dysregulated circRNAs. In addition, microRNAs that may be associated with specific circRNAs were predicted using miRanda. Collectively, the present results indicated the potential importance of circRNAs in the peripheral blood of neonates with HIE.