Selective vulnerability in the developing central nervous system

Seeing beyond words: Visualizing autism spectrum disorder biomarker insights

Objective

This study employs bibliometric and visual analysis to elucidate global research trends in Autism Spectrum Disorder (ASD) biomarkers, identify critical research focal points, and discuss the potential integration of diverse biomarker modalities for precise ASD assessment.

Methods

A comprehensive bibliometric analysis was conducted using data from the Web of Science Core Collection database until December 31, 2022. Visualization tools, including R, VOSviewer, CiteSpace, and gCLUTO, were utilized to examine collaborative networks, co-citation patterns, and keyword associations among countries, institutions, authors, journals, documents, and keywords.

Results

ASD biomarker research emerged in 2004, accumulating a corpus of 4348 documents by December 31, 2022. The United States, with 1574 publications and an H-index of 213, emerged as the most prolific and influential country. The University of California, Davis, contributed significantly with 346 publications and an H-index of 69, making it the leading institution. Concerning journals, the Journal of Autism and Developmental Disorders, Autism Research, and PLOS ONE were the top three publishers of ASD biomarker-related articles among a total of 1140 academic journals. Co-citation and keyword analyses revealed research hotspots in genetics, imaging, oxidative stress, neuroinflammation, gut microbiota, and eye tracking. Emerging topics included "DNA methylation," "eye tracking," "metabolomics," and "resting-state fMRI."

Conclusion

The field of ASD biomarker research is dynamically evolving. Future endeavors should prioritize individual stratification, methodological standardization, the harmonious integration of biomarker modalities, and longitudinal studies to advance the precision of ASD diagnosis and treatment.

Short-term hyperoxia-induced functional and morphological changes in rat hippocampus

Excess oxygen (O2) levels may have a stimulating effect, but in the long term, and at high concentrations of O2, it is harmful to the nervous system. The hippocampus is very sensitive to pathophysiological changes and altered O2 concentrations can interfere with hippocampus-dependent learning and memory functions. In this study, we investigated the hyperoxia-induced changes in the rat hippocampus to evaluate the short-term effect of mild and severe hyperoxia. Wistar male rats were randomly divided into control (21% O2), mild hyperoxia (30% O2), and severe hyperoxia groups (100% O2). The O2 exposure lasted for 60 min. Multi-channel silicon probes were used to study network oscillations and firing properties of hippocampal putative inhibitory and excitatory neurons. Neural damage was assessed using the Gallyas silver impregnation method. Mild hyperoxia (30% O2) led to the formation of moderate numbers of silver-impregnated "dark" neurons in the hippocampus. On the other hand, exposure to 100% O2 was associated with a significant increase in the number of "dark" neurons located mostly in the hilus. The peak frequency of the delta oscillation decreased significantly in both mild and severe hyperoxia in urethane anesthetized rats. Compared to normoxia, the firing activity of pyramidal neurons under hyperoxia increased while it was more heterogeneous in putative interneurons in the cornu ammonis area 1 (CA1) and area 3 (CA3). These results indicate that short-term hyperoxia can change the firing properties of hippocampal neurons and network oscillations and damage neurons. Therefore, the use of elevated O2 concentration inhalation in hospitals (i.e., COVID treatment and surgery) and in various non-medical scenarios (i.e., airplane emergency O2 masks, fire-fighters, and high altitude trekkers) must be used with extreme caution.

Neuroprotective efficacy of hypothermia and Inter-alpha Inhibitor Proteins after hypoxic ischemic brain injury in neonatal rats

Therapeutic hypothermia is the standard of care for hypoxic-ischemic (HI) encephalopathy. Inter-alpha Inhibitor Proteins (IAIPs) attenuate brain injury after HI in neonatal rats. Human (h) IAIPs (60 ​mg/kg) or placebo (PL) were given 15 ​min, 24 and 48 ​h to postnatal (P) day-7 rats after carotid ligation and 8% oxygen for 90 ​min with (30 ​°C) and without (36 ​°C) exposure to hypothermia 1.5 ​h after HI for 3 ​h. Hemispheric volume atrophy (P14) and neurobehavioral tests including righting reflex (P8-P10), small open field (P13-P14), and negative geotaxis (P14) were determined. Hemispheric volume atrophy in males was reduced (P ​< ​0.05) by 41.9% in the normothermic-IAIP and 28.1% in the hypothermic-IAIP compared with the normothermic-PL group, and in females reduced (P ​< ​0.05) by 30.3% in the normothermic-IAIP, 45.7% in hypothermic-PL, and 55.2% in hypothermic-IAIP compared with the normothermic-PL group after HI. Hypothermia improved (P ​< ​0.05) the neuroprotective effects of hIAIPs in females. The neuroprotective efficacy of hIAIPs was comparable to hypothermia in female rats (P ​= ​0.183). Treatment with hIAIPs, hypothermia, and hIAIPs with hypothermia decreased (P ​< ​0.05) the latency to enter the peripheral zone in the small open field test in males. We conclude that hIAIPs provide neuroprotection from HI brain injury that is comparable to the protection by hypothermia, hypothermia increases the effects of hIAIPs in females, and hIAIPs and hypothermia exhibit some sex-related differential effects.

Metabolic Syndrome: A Narrative Review from the Oxidative Stress to the Management of Related Diseases

Metabolic syndrome (MS) is a growing disorder affecting thousands of people worldwide, especially in industrialised countries, increasing mortality. Oxidative stress, hyperglycaemia, insulin resistance, inflammation, dysbiosis, abdominal obesity, atherogenic dyslipidaemia and hypertension are important factors linked to MS clusters of different pathologies, such as diabesity, cardiovascular diseases and neurological disorders. All biochemical changes observed in MS, such as dysregulation in the glucose and lipid metabolism, immune response, endothelial cell function and intestinal microbiota, promote pathological bridges between metabolic syndrome, diabesity and cardiovascular and neurodegenerative disorders. This review aims to summarise metabolic syndrome's involvement in diabesity and highlight the link between MS and cardiovascular and neurological diseases. A better understanding of MS could promote a novel strategic approach to reduce MS comorbidities.

Early Neuroprotective Effects of Bovine Lactoferrin Associated with Hypothermia after Neonatal Brain Hypoxia-Ischemia in Rats

Neonatal hypoxic-ischemic (HI) encephalopathy (HIE) in term newborns is a leading cause of mortality and chronic disability. Hypothermia (HT) is the only clinically available therapeutic intervention; however, its neuroprotective effects are limited. Lactoferrin (LF) is the major whey protein in milk presenting iron-binding, anti-inflammatory and anti-apoptotic properties and has been shown to protect very immature brains against HI damage. We hypothesized that combining early oral administration of LF with whole body hypothermia could enhance neuroprotection in a HIE rat model. Pregnant Wistar rats were fed an LF-supplemented diet (1 mg/kg) or a control diet from (P6). At P7, the male and female pups had the right common carotid artery occluded followed by hypoxia (8% O2 for 60') (HI). Immediately after hypoxia, hypothermia (target temperature of 32.5-33.5 °C) was performed (5 h duration) using Criticool®. The animals were divided according to diet, injury and thermal condition. At P8 (24 h after HI), the brain neurochemical profile was assessed using magnetic resonance spectroscopy (1H-MRS) and a hyperintense T2W signal was used to measure the brain lesions. The mRNA levels of the genes related to glutamatergic excitotoxicity, energy metabolism and inflammation were assessed in the right hippocampus. The cell markers and apoptosis expression were assessed using immunofluorescence in the right hippocampus. HI decreased the energy metabolites and increased lactate. The neuronal-astrocytic coupling impairments observed in the HI groups were reversed mainly by HT. LF had an important effect on astrocyte function, decreasing the levels of the genes related to glutamatergic excitotoxicity and restoring the mRNA levels of the genes related to metabolic support. When combined, LF and HT presented a synergistic effect and prevented lactate accumulation, decreased inflammation and reduced brain damage, pointing out the benefits of combining these therapies. Overall, we showed that through distinct mechanisms lactoferrin can enhance neuroprotection induced by HT following neonatal brain hypoxia-ischemia.

Predictive Value of MRI in Hypoxic-Ischemic Encephalopathy Treated with Therapeutic Hypothermia

Background: Hypoxic-ischemic encephalopathy (HIE) is a severe pathology, and no unique predictive biomarker has been identified. Our aims are to identify associations of perinatal and outcome parameters with morphological anomalies and ADC values from MRI. The secondary aims are to define a predictive ADC threshold value and detect ADC value fluctuations between MRIs acquired within 7 days (MR0) and at 1 year (MR1) of birth in relation to perinatal and outcome parameters. Methods: Fifty-one term children affected by moderate HIE treated with hypothermia and undergoing MRI0 and MRI1 were recruited. Brain MRIs were evaluated through the van Rooij score, while ADC maps were co-registered on a standardized cerebral surface, on which 29 ROIs were drawn. Statistical analysis was performed in Matlab, with the statistical significance value at 0.05. Results: ADC0 < ADC1 in the left and right thalami, left and right frontal white matter, right visual cortex, and the left dentate nucleus of children showing abnormal perinatal and neurodevelopmental parameters. At ROC analysis, the best prognostic ADC cut-off value was 1.535 mm2/s × 10−6 (sensitivity 80%, specificity 86%) in the right frontal white matter. ADC1 > ADC0 in the right visual cortex and left dentate nucleus, positively correlated with multiple abnormal perinatal and neurodevelopmental parameters. The van Rooij score was significantly higher in children presenting with sleep disorders. Conclusions: ADC values could be used as prognostic biomarkers to predict children’s neurodevelopmental outcomes. Further studies are needed to address these crucial topics and validate our results. Early and multidisciplinary perinatal evaluation and the subsequent re-assessment of children are pivotal to identify physical and neuropsychological disorders to guarantee early and tailored therapy.

An infantile traumatic brain injury with a bright tree appearance detected before the late seizure

INDRODUCTION

Infantile traumatic brain injury (TBI) rarely follows a biphasic clinical course and exhibits a bright tree appearance (BTA) on magnetic resonance imaging (MRI). This is termed infantile traumatic brain injury with a biphasic clinical course and late reduced diffusion (TBIRD). TBIRD has clinical features similar to those of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD). It remains to be clarified which patients with infantile TBI will develop TBIRD and the prevention and treatment of TBIRD.

CASE AND REVIEW

We report a case of TBIRD that exhibited BTA 1 day before the late seizure and review 12 cases of TBIRD. All patients developed a subdural hematoma (SDH), were younger than 2 years, and presented with a biphasic phase within 3-6 days. The median interval between BTA and TBI was 5 days. Of the 5 cases examined with MRI before the biphasic phase, only our case was detected with BTA 4 days after TBI.

CONCLUSION

Predicting the biphasic clinical course may be possible by examining MRI after TBI in patients under 2 years of age who develop SDH with unconsciousness, seizure, or hemiplegia, and these patients should be strictly followed up for 1 week.

Effect of Hypothermia on Serum Myelin Basic Protein and Tumor Necrosis Factor-α in Neonatal Hypoxic-Ischemic Encephalopathy

OBJECTIVE

Multiple randomized controlled trials have shown that hypothermia is a safe and effective treatment for neonatal moderate or severe hypoxic-ischemic encephalopathy (HIE). The neuroprotective mechanisms of hypothermia need further study. The aim of this study was to investigate the effect of hypothermia on the serum levels of myelin basic protein (MBP) and tumor necrosis factor-α (TNF-α) as well as neurodevelopmental outcomes in neonatal HIE.

STUDY DESIGN

Eighty-five neonates with moderate-to-severe HIE were divided into a hypothermia group (n = 49) and a control group (n = 36). Serum levels of MBP and TNF-α within 6 hours after birth and after 3 days of treatment were determined by enzyme-linked immunosorbent assay, and neurodevelopmental outcome at the age of 12 to 15 months was assessed by using the Gesell development scale.

RESULTS

After 3 days of treatment, serum levels of MBP and TNF-α in the control group were not significantly different from levels before treatment (p > 0.05), and serum levels of MBP and TNF-α in the hypothermia group were significantly lower than levels before treatment (p < 0.05). Serum levels of MBP and TNF-α were significantly negatively correlated with developmental quotient (DQ; r =  - 0.7945, p = 0.0000; r =  - 0.7035, p = 0.0000, respectively). Serum levels of MBP and TNF-α in neurodevelopmentally impaired infants were significantly higher than those in infants with suspected neurodevelopmental impairment and those in neurodevelopmentally normal infants (both p < 0.01). The rate of reduction of neurodevelopmental impairment was higher among infants in the hypothermia group than among those in the control group (χ² = 16.3900, p < 0.05).

CONCLUSION

Hypothermia can reduce serum levels of MBP and TNF-α in neonates with HIE. Inhibiting the release of TNF-α may be one of the mechanisms by which hypothermia protects the myelin sheath.

KEY POINTS

· Hypothermia can reduce serum levels of MBP and TNF-α in neonatal HIE.. · Hypothermia improves neurodevelopmental outcomes and reduces the rate of neurodevelopmental impairment.. · Hypothermia is a feasible and effective treatment for neonates with moderate or severe HIE..

Novel injury scoring tool for assessing brain injury following neonatal hypoxia-ischemia in mice

The variability of severity in hypoxia ischemia (HI) induced brain injury among research subjects is a major challenge in developmental brain injury research. Our laboratory developed a novel injury scoring tool based on our gross pathological observations during hippocampal extraction. The hippocampi received scores of 0-6 with 0 being no injury and 6 being severe injury post-HI. The hippocampi exposed to sham surgery were grouped as having no injury. We have validated the injury scoring tool with T2-weighted MRI analysis of percent hippocampal/hemispheric tissue loss and cell survival/death markers after exposing the neonatal mice to Vannucci's rodent model of neonatal HI. In addition, we have isolated hippocampal nuclei and quantified the percent good quality nuclei to provide an example of utilization of our novel injury scoring tool. Our novel injury scores correlated significantly with percent hippocampal and hemispheric tissue loss, cell survival/death markers, and percent good quality nuclei. Caspase-3 and Poly (ADP-ribose) polymerase-1 (PARP1) have been implicated in different cell death pathways in response to neonatal HI. Another gene, sirtuin1 (SIRT1), has been demonstrated to have neuroprotective and anti-apoptotic properties. To assess the correlation between the severity of injury and genes involved in cell survival/death, we analyzed caspase-3, PARP1, and SIRT1 mRNA expressions in hippocampi 3 days post-HI and sham surgery, using RT-qPCR. The ipsilateral (IL) hippocampal caspase-3 and SIRT1 mRNA expressions post-HI were significantly higher than sham IL hippocampi, and positively correlated with the novel injury scores in both males and females. We detected a statistically significant sex difference in IL hippocampal caspase-3 mRNA expression with comparable injury scores between males and females with higher expression in females.

Re-evaluation of medical findings in alleged shaken baby syndrome and abusive head trauma in Norwegian courts fails to support abuse diagnoses

AIM

The criteria for diagnosing abusive head trauma (AHT) are not well defined and this condition might be diagnosed on failing premises. Our aim was to review criminal AHT cases in Norwegian courts by scrutinising the underlying medical documentation.

METHODS

Cases were identified in the data registry for Norwegian courts from 2004 to 2015. Documentation was obtained from relevant health institutions. The medical co-authors first made independent evaluations of the documentation for each child, followed by a consensus evaluation.

RESULTS

A total of 17 children (11 boys) were identified, all diagnosed as AHT by court appointed experts, 15 were infants (mean age 2.6 months). A high proportion (41.2%) was born to immigrant parents and 31.3% were premature. The medical findings could be explained by alternative diagnoses in 16 of the 17 children; 8 boys (7 infants - mean age 2.9 months) had clinical and radiological characteristics compatible with external hydrocephalus complicated by chronic subdural haematoma. Six children (five infants with mean age 2.1 months) had a female preponderance and findings compatible with hypoxic ischaemic insults.

CONCLUSION

The medical condition in most children had not necessarily been caused by shaking or direct impact, as was originally concluded by the court experts.

Inter-alpha Inhibitor Proteins Ameliorate Brain Injury and Improve Behavioral Outcomes in a Sex-Dependent Manner After Exposure to Neonatal Hypoxia Ischemia in Newborn and Young Adult Rats

Hypoxic-ischemic (HI) brain injury is a major contributor to neurodevelopmental morbidities. Inter-alpha inhibitor proteins (IAIPs) have neuroprotective effects on HI-related brain injury in neonatal rats. However, the effects of treatment with IAIPs on sequential behavioral, MRI, and histopathological abnormalities in the young adult brain after treatment with IAIPs in neonates remain to be determined. The objective of this study was to examine the neuroprotective effects of IAIPs at different neurodevelopmental stages from newborn to young adults after exposure of neonates to HI injury. IAIPs were given as 11-sequential 30-mg/kg doses to postnatal (P) day 7-21 rats after right common carotid artery ligation and exposure to 90 min of 8% oxygen. The resulting brain edema and injury were examined by T2-weighted magnetic resonance imaging (MRI) and cresyl violet staining, respectively. The mean T2 values of the ipsilateral hemisphere from MRI slices 6 to 10 were reduced in IAIP-treated HI males + females on P8, P9, and P10 and females on P8, P9, P10, and P14. IAIP treatment reduced hemispheric volume atrophy by 44.5 ± 29.7% in adult male + female P42 rats and improved general locomotor abilities measured by the righting reflex over time at P7.5, P8, and P9 in males + females and males and muscle strength/endurance measured by wire hang on P16 in males + females and females. IAIPs provided beneficial effects during the learning phase of the Morris water maze with females exhibiting beneficial effects. IAIPs confer neuroprotection from HI-related brain injury in neonates and even in adult rats and beneficial MRI and behavioral benefits in a sex-dependent manner.

Melatonin Reduces Neuroinflammation and Improves Axonal Hypomyelination by Modulating M1/M2 Microglia Polarization via JAK2-STAT3-Telomerase Pathway in Postnatal Rats Exposed to Lipopolysaccharide

Microglia activation and associated inflammation are implicated in the periventricular white matter damage (PWMD) in septic postnatal rats. This study investigated whether melatonin would mitigate inflammation and alleviate the axonal hypomyelination in the corpus callosum in septic postnatal rats. We further explored if this might be related to the modulation of microglial polarization from M1 phenotype to M2 through the JAK2/STAT3/telomerase pathway. We reported here that indeed melatonin not only can it reduce the neurobehavioral disturbances in LPS-injected rats, but it can also dampen microglia-mediated inflammation. Thus, in LPS + melatonin group, the expression of proinflammatory mediators in M1 phenotype microglia was downregulated. As opposed to this, M2 microglia were increased which was accompanied by upregulated expression of anti-inflammatory mediators along with telomerase reverse transcriptase or melatonin receptor 1(MT1). In parallel to this was decreased NG2 expression but increased expression of myelin and neurofilament proteins. Melatonin can improve hypomyelination which was confirmed by electron microscopy. In vitro in primary microglia stimulated by LPS, melatonin decreased the expression of proinflammatory mediators significantly; but it increased the expression of anti-inflammatory mediators. Additionally, the expression levels of p-JAK2 and p-STAT3 were significantly elevated in microglia after melatonin treatment. Remarkably, the effect of melatonin on LPS-treated microglia was blocked by melatonin receptor, JAK2, STAT3 and telomerase reverse transcriptase inhibitors, respectively. Taken together, it is concluded that melatonin can attenuate PWMD through shifting M1 microglia towards M2 via MT1/JAK2/STAT3/telomerase pathway. The results suggest a new therapeutic strategy whereby melatonin may be adopted to convert microglial polarization from M1 to M2 phenotype that would ultimately contribute to the attenuation of PWMD.

Sildenafil-Mediated Neuroprotection from Adult to Neonatal Brain Injury: Evidence, Mechanisms, and Future Translation

Cerebral stroke, traumatic brain injury, and hypoxic ischemic encephalopathy are among the most frequently occurring brain injuries. A complex pathogenesis, characterized by a synergistic interaction between alterations of the cerebrovascular system, cell death, and inflammation, is at the basis of the brain damage that leads to behavioral and neurodevelopmental disabilities in affected subjects. Sildenafil is a selective inhibitor of the enzyme phosphodiesterase 5 (PDE5) that is able to cross the blood-brain barrier. Preclinical data suggest that sildenafil may be a good candidate for the prevention or repair of brain injury in both adults and neonates. The aim of this review is to summarize the evidence supporting the neuroprotective action of sildenafil and discuss the possible benefits of the association of sildenafil with current therapeutic strategies.

All Roads Lead to Rome: Different Molecular Players Converge to Common Toxic Pathways in Neurodegeneration

Multiple neurodegenerative diseases (NDDs) such as Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) and Huntington’s disease (HD) are being suggested to have common cellular and molecular pathological mechanisms, characterized mainly by protein misfolding and aggregation. These large inclusions, most likely, represent an end stage of a molecular cascade; however, the soluble misfolded proteins, which take part in earlier steps of this cascade, are the more toxic players. These pathological proteins, which characterize each specific disease, lead to the selective vulnerability of different neurons, likely resulting from a combination of different intracellular mechanisms, including mitochondrial dysfunction, ER stress, proteasome inhibition, excitotoxicity, oxidative damage, defects in nucleocytoplasmic transport, defective axonal transport and neuroinflammation. Damage within these neurons is enhanced by damage from the nonneuronal cells, via inflammatory processes that accelerate the progression of these diseases. In this review, while acknowledging the hallmark proteins which characterize the most common NDDs; we place specific focus on the common overlapping mechanisms leading to disease pathology despite these different molecular players and discuss how this convergence may occur, with the ultimate hope that therapies effective in one disease may successfully translate to another.

Developmental and Interventional Plasticity of Motor Maps after Perinatal Stroke

Within the perinatal stroke field, there is a need to establish preclinical models where putative biomarkers for motor function can be examined. In a mouse model of perinatal stroke, we evaluated motor map size and movement latency following optogenetic cortical stimulation against three factors of post-stroke biomarker utility: (1) correlation to chronic impairment on a behavioral test battery; (2) amenability to change using a skilled motor training paradigm; and (3) ability to distinguish individuals with potential to respond well to training. Thy1-ChR2-YFP mice received a photothrombotic stroke at postnatal day 7 and were evaluated on a battery of motor tests between days 59 and 70. Following a cranial window implant, mice underwent longitudinal optogenetic motor mapping both before and after 3 weeks of skilled forelimb training. Map size and movement latency of both hemispheres were positively correlated with impaired spontaneous forelimb use, whereas only ipsilesional hemisphere map size was correlated with performance in skilled reaching. Map size and movement latency did not show groupwise changes with training; however, mice with the smallest pretraining map sizes and worst impairments demonstrated the greatest expansion of map size in response to skilled forelimb training. Overall, motor map size showed utility as a potential biomarker for impairment and training-induced modulation in specific individuals. Future assessment of the predictive capacity of post-stroke motor representations for behavioral outcome in animal models opens the possibility of dissecting how plasticity mechanisms contribute to recovery following perinatal stroke.SIGNIFICANCE STATEMENT We investigated the utility of two cortical motor representation measures (motor map size and movement onset latency) as potential biomarkers for post-stroke motor recovery in a mouse model of perinatal stroke. Both motor map size and movement latency were associated with functional recovery after perinatal stroke, with map size showing an additional association between training responsiveness and severity of impairment. Overall, both motor map size and movement onset latency show potential as neurophysiological correlates of recovery. As such, future studies of perinatal stroke rehabilitation and neuromodulation should include these measures to help explain neurophysiological changes that might be occurring in response to treatment.

The General Movements Assessment in Neonates With Hypoxic Ischemic Encephalopathy

BACKGROUND

Clinical measures after birth and studies such as electroencephalogram (EEG) and brain imaging do not fully predict neurodevelopmental outcomes of infants with hypoxic-ischemic encephalopathy. Early detection of adverse neurologic outcomes, and cerebral palsy in particular, in high-risk infants is essential for ensuring timely management. The General Movements Assessment is a tool that can be used in the early detection of cerebral palsy in infants with brain injury. The majority of studies on the General Movements Assessment in the late preterm and term population were performed prior to the introduction of therapeutic hypothermia.

AIMS

To apply the General Movements Assessment in late preterm and term infants with hypoxic-ischemic encephalopathy (including those who received therapeutic hypothermia), to determine if clinical markers of hypoxic-ischemic encephalopathy predict abnormal General Movements Assessment findings, and to evaluate interrater reliability of the General Movements Assessment in this population. Study design: Pilot prospective cohort study Subjects: We assessed 29 late preterm and full-term infants with mild, moderate, and severe hypoxic-ischemic encephalopathy in Philadelphia, PA.

RESULTS

Most infants' general movements normalized by the fidgety age. Only infants with moderate or severe hypoxic-ischemic encephalopathy had abnormal general movements in both the writhing and the fidgety ages (n = 6). Seizure at any point during the initial hospitalization was the clinical sign most predictive of abnormal general movements in the fidgety age (sensitivity 100%, specificity 55%, positive predictive value 40%, negative predictive value 100%). Interrater reliability was greatest during the fidgety age (κ = 0.67).

CONCLUSIONS

Seizures were the clinical predictor most closely associated with abnormal findings on the General Movements Assessment. However, clinical markers of hypoxic-ischemic encephalopathy are not fully predictive of abnormal General Movements Assessment findings. Larger future studies are needed to evaluate the associations between the General Movements Assessment and childhood neurologic outcomes in patients with hypoxic-ischemic encephalopathy who received therapeutic hypothermia.

Paeoniflorin treatment regulates TLR4/NF-κB signaling, reduces cerebral oxidative stress and improves white matter integrity in neonatal hypoxic brain injury

Neonatal hypoxia/ischemia (H/I), injures white matter, results in neuronal loss, disturbs myelin formation, and neural network development. Neuroinflammation and oxidative stress have been reported in neonatal hypoxic brain injuries. We investigated whether Paeoniflorin treatment reduced H/I-induced inflammation and oxidative stress and improved white matter integrity in a neonatal rodent model. Seven-day old Sprague–Dawley pups were exposed to H/I. Paeoniflorin (6.25, 12.5, or 25 mg/kg body weight) was administered every day via oral gavage from postpartum day 3 (P3) to P14, and an hour before induction of H/I. Pups were sacrificed 24 h (P8) and 72 h (P10) following H/I. Paeoniflorin reduced the apoptosis of neurons and attenuated cerebral infarct volume. Elevated expression of cleaved caspase-3 and Bad were regulated. Paeoniflorin decreased oxidative stress by lowering levels of malondialdehyde and reactive oxygen species generation and while, and it enhanced glutathione content. Microglial activation and the TLR4/NF-κB signaling were significantly down-regulated. The degree of inflammatory mediators (interleukin 1β and tumor necrosis factor-α) were reduced. Paeoniflorin markedly prevented white matter injury via improving expression of myelin binding protein and increasing O1-positive olidgodendrocyte and O4-positive oligodendrocyte counts. The present investigation demonstrates the potent protective efficiency of paeoniflorin supplementation against H/I-induced brain injury by effectually preventing neuronal loss, microglial activation, and white matter injury via reducing oxidative stress and inflammatory pathways.

Mitochondrial dysfunction and traffic jams in amyotrophic lateral sclerosis

Neurodegenerative diseases are characterized by progressive neuronal loss anatomically or physiologically and accumulation of protein in the cells. Mitochondria provide energy to these neuronal cells consuming 20% of the body's oxygen. Mitochondria are the dynamic membrane-bound cell organelles that function to generate ATP, regulate calcium homeostasis, and produce reactive oxygen species. Because of alterations in the electron transport chain, mutation, and environmental toxins, there is reduced ATP production, calcium dyshomeostasis, and increased oxidative stress, resulting in mitochondrial dysfunction, leading to the pathogenesis of neurodegenerative diseases such as ALS. ALS is described as the loss of upper and lower motor neurons resulting in progressive muscle denervation and loss of voluntary movements. There are multiple shreds of evidence in the literature regarding the mechanism involved in mitochondrial dysfunction and possible therapeutic targets to treat the condition. Moreover, different studies reported the role of different gene mutations and malfunctions in transport system responsible for the accumulation and aggregation of the proteins inside the brain cells. This accumulation and/or aggregation of proteins in the neuronal cells is known as neuronal traffic jam, which also plays the leading role in the progressive neurodegenerative diseases. In this review, we have elucidated the critical insights into mitochondrial dysfunction and neuronal traffic jam; and its role in the initiation and progression of ALS. Moreover, the pharmacological targets and possible conducts to this scenario are also brought together.

Inhibition of NOD1 Attenuates Neonatal Hypoxia-Ischemia Induced Long-Term Cognitive Impairments in Mice Through Modulation of Autophagy-Related Proteins

BACKGROUND

Autophagy is implicated in neonatal hypoxia-ischemia (HI) induced cognitive impairment. The nucleotide-oligomerizing domain-1 (NOD1), a protein involved in inflammatory responses, has been shown to activate autophagy to promote progression of other diseases. We aimed to investigate whether and how NOD1 is involved in HI-induced brain injury using an HI mouse model.

METHODS

We induced HI in neonatal mice and examined levels of NOD1 and genes associated with autophagy. We then inhibited NOD1 by intracerebroventricular injection of si-NOD1 following HI induction and tested the effects on autophagy, inflammatory responses and long-term behavioral outcomes through Morris water maze and open field tests.

RESULTS

We found that HI induction significantly elevated mRNA levels of NOD1 (3.54 folds change) and autophagy-related genes including Atg5 (3.89 folds change) and Beclin-1 (3.34 folds change). NOD1 inhibition following HI induction suppressed autophagy signaling as well as HI induced proinflammatory cytokine production. Importantly, NOD1 inhibition after HI improved long-term cognitive function, without impacting exploratory and locomotor activities.

CONCLUSION

We show here that NOD1 is involved in the pathogenesis of HI-induced brain injury through modulation of autophagy-related proteins and inflammatory responses. Our findings suggest that NOD1 may be a potent target for developing therapeutic strategies for treating HI-induced brain injury.

Mitohormesis; Potential implications in neurodegenerative diseases

Mitochondrial dysfunction is known to be associated with neurodegenerative diseases (NDDs), which is a major burden on the society. Therefore, understanding the regulation of mitochondrial dysfunctions and its implication in neurodegeneration has been major goal for exploiting these mechanisms to rescue neuronal death. The crosstalk between mitochondria and nucleus is important for different neuronal functions including axonal branching, energy homeostasis, neuroinflammation and neuronal survival. The decreased mitochondria capacity during progressive neurodegeneration leads to the altered OXPHOS activity and generation of ROS. The ROS levels in narrow physiological range can reprogram nuclear gene expression to enhance the cellular survival by phenomenon called mitohormesis. Here, we have systematically reviewed the existing reports of mitochondrial dysfunctions causing altered ROS levels in NDDs. We further discussed the role of ROS in regulating mitohormesis and emphasized the importance of mitohormesis in neuronal homeostasis. The emerging role of mitohormesis highlights its importance in future studies on intracellular ROS mediated rescue of mitochondrial dysfunction along with other prevailing mechanisms to alleviate neurodegeneration.

Memory-Like Responses of Brain Microglia Are Controlled by Developmental State and Pathogen Dose

Microglia, the innate immune cells of the central nervous system, feature adaptive immune memory with implications for brain homeostasis and pathologies. However, factors involved in the emergence and regulation of these opposing responses in microglia have not been fully addressed. Recently, we showed that microglia from the newborn brain display features of trained immunity and immune tolerance after repeated contact with pathogens in a dose-dependent manner. Here, we evaluate the impact of developmental stage on adaptive immune responses of brain microglia after repeated challenge with ultra-low (1 fg/ml) and high (100 ng/ml) doses of the endotoxin LPS in vitro. We find that priming of naïve microglia derived from newborn but not mature and aged murine brain with ultra-low LPS significantly increased levels of pro-inflammatory mediators TNF-α, IL-6, IL-1β, MMP-9, and iNOS as well as neurotrophic factors indicating induction of trained immunity (p < 0.05). In contrast, stimulation with high doses of LPS led to a robust downregulation of pro-inflammatory cytokines and iNOS independent of the developmental state, indicating induced immune tolerance. Furthermore, high-dose priming with LPS upregulated anti-inflammatory mediators IL-10, Arg-1, TGF- β, MSR1, and IL-4 in newborn microglia (p < 0.05). Our data indicate pronounced plasticity of the immune response of neonate microglia compared with microglia derived from mature and aged mouse brain. Induced trained immunity after priming with ultra-low LPS doses may be responsible for enhanced neuro-inflammatory susceptibility of immature brain. In contrast, the immunosuppressed phenotype following high-dose LPS priming might be prone to attenuate excessive damage after recurrent systemic inflammation.

Effects of inter-alpha inhibitor proteins on brain injury after exposure of neonatal rats to severe hypoxia-ischemia

Hypoxic-ischemic (HI) brain injury is one of the most common neurological problems occurring in premature and full-term infants after perinatal complications. Hypothermia is the only treatment approved for HI encephalopathy in newborns. However, this treatment is only partially protective, cannot be used to treat premature infants, and has limited efficacy to treat severe HI encephalopathy. Inflammation contributes to the evolution of HI brain injury in neonates. Inter-alpha Inhibitor Proteins (IAIPs) are immunomodulatory proteins that have neuroprotective properties after exposure to moderate HI in neonatal rats. The objective of the current study was to determine the neuroprotective efficacy of treatment with IAIPs starting immediately after or with a delay of one hour after exposure to severe HI of 120 min duration. One hundred and forty-six 7-day-old rat pups were randomized to sham control, HI and immediate treatment with IAIPs (60 mg/kg) or placebo (PL), and sham, HI and delayed treatment with IAIPs or PL. IAIPs or PL were given at zero, 24, and 48 h after HI or 1, 24 and 48 h after HI. Total brain infarct volume was determined 72 h after exposure to HI. Treatment with IAIPs immediately after HI decreased (P < 0.05) infarct volumes by 58.0% and 44.5% in male and female neonatal rats, respectively. Delayed treatment with IAIPs after HI decreased (P < 0.05) infarct volumes by 23.7% in male, but not in female rats. We conclude that IAIPs exert neuroprotective effects even after exposure to severe HI in neonatal rats and appear to exhibit some sex-related differential effects.

Effects of delayed intraventricular TLR7 agonist administration on long-term neurological outcome following asphyxia in the preterm fetal sheep

In the preterm brain, accumulating evidence suggests toll-like receptors (TLRs) are key mediators of the downstream inflammatory pathways triggered by hypoxia-ischemia (HI), which have the potential to exacerbate or ameliorate injury. Recently we demonstrated that central acute administration of the TLR7 agonist Gardiquimod (GDQ) confers neuroprotection in the preterm fetal sheep at 3 days post-asphyxial recovery. However, it is unknown whether GDQ can afford long-term protection. To address this, we examined the long-term effects of GDQ. Briefly, fetal sheep (0.7 gestation) received sham asphyxia or asphyxia induced by umbilical cord occlusion, and were studied for 7 days recovery. Intracerebroventricular (ICV) infusion of GDQ (total dose 3.34 mg) or vehicle was performed from 1-4 hours after asphyxia. GDQ was associated with a robust increase in concentration of tumor necrosis factor-(TNF)-α in the fetal plasma, and interleukin-(IL)-10 in both the fetal plasma and cerebrospinal fluid. GDQ did not significantly change the number of total and immature/mature oligodendrocytes within the periventricular and intragyral white matter. No changes were observed in astroglial and microglial numbers and proliferating cells in both white matter regions. GDQ increased neuronal survival in the CA4 region of the hippocampus, but was associated with exacerbated neuronal injury within the caudate nucleus. In conclusion, our data suggest delayed acute ICV administration of GDQ after severe HI in the developing brain may not support long-term neuroprotection.

Neonatal Neuroimaging

Significant advances in the field of neonatal imaging has resulted in the generation of large complex data sets of relevant information for routine daily clinical practice, and basic and translational research. The evaluation of this data is a complex task for the neonatal imager who must distinguish normal and incidental findings from clinically significant abnormalities which are often adjunctive data points applicable to clinical evaluation and treatment. This review provides an overview of the imaging manifestations of disease processes commonly encountered in the neonatal brain. Since MRI is currently the highest yield technique for the diagnosis and characterization of the normal and abnormal brain, it is therefore the focus of the majority of this review. When applicable, discussion of some of the pertinent known pathophysiology and neuropathological aspects of disease processes are reviewed.

Free radicals and neonatal encephalopathy: mechanisms of injury, biomarkers, and antioxidant treatment perspectives

Neonatal encephalopathy (NE), most commonly a result of the disruption of cerebral oxygen delivery, is the leading cause of neurologic disability in term neonates. Given the key role of free radicals in brain injury development following hypoxia-ischemia-reperfusion, several oxidative biomarkers have been explored in preclinical and clinical models of NE. Among these, antioxidant enzyme activity, uric acid excretion, nitric oxide, malondialdehyde, and non-protein-bound iron have shown promising results as possible predictors of NE severity and outcome. Owing to high costs and technical complexity, however, their routine use in clinical practice is still limited. Several strategies aimed at reducing free radical production or upregulating physiological scavengers have been proposed for NE. Room-air resuscitation has proved to reduce oxidative stress following perinatal asphyxia and is now universally adopted. A number of medications endowed with antioxidant properties, such as melatonin, erythropoietin, allopurinol, or N-acetylcysteine, have also shown potential neuroprotective effects in perinatal asphyxia; nevertheless, further evidence is needed before these antioxidant approaches could be implemented as standard care.

The fluctuations of metabotropic glutamate receptor subtype 5 (mGluR5) in the amygdala in fear conditioning model of male Wistar rats following sleep deprivation, reverse circadian and napping

Sleep is involved in metabolic system, mental health and cognitive functions. Evidence shows that sleep deprivation (SD) negatively affects mental health and impairs cognitive functions, including learning and memory. Furthermore, the metabotropic glutamate receptor subtype 5 (mGluR5) is a metabolic biomarker, which is affected by various conditions, including stress, sleep deprivation, and cognitive and psychiatric disorders. In this research, we investigated the effect of SD and reverse circadian (RC), and two models of napping (continuous and non-continuous) combined with SD or RC on fear-conditioning memory, anxiety-like behavior and mGluR5 fluctuations in the amygdala. 64 male Wistar rats were used in this study. The water box apparatus was used to induce SD/RC for 48 h, and fear-conditioning memory apparatus was used to assess fear memory. The results showed, fear-conditioning memory was impaired following SD and RC, especially in contextual stage. However, anxiety-like behavior was increased. Furthermore, mGluR5 was increased in the left amygdala more than the right amygdala. Additionally, continuous napping significantly improved fear-conditioning memory, especially freezing behavior. In conclusion, following SD and RC, fear-conditioning memory in contextual stage is more vulnerable than in auditory stage. Furthermore, increase in anxiety-like behavior is related to increase in the activity of left amygdala and mGluR5 receptors.

Transient effect of melatonin treatment after neonatal hypoxic-ischemic brain injury in rats

Melatonin has potential neuroprotective capabilities after neonatal hypoxia-ischemia (HI), but long-term effects have not been investigated. We hypothesized that melatonin treatment directly after HI could protect against early and delayed brain injury. Unilateral HI brain injury was induced in postnatal day 7 rats. An intraperitoneal injection of either melatonin or vehicle was given at 0, 6 and 25 hours after hypoxia. In-vivo MRI was performed 1, 7, 20 and 43 days after HI, followed by histological analysis. Forelimb asymmetry and memory were assessed at 12–15 and at 36–43 days after HI. More melatonin treated than vehicle treated animals (54.5% vs 15.8%) developed a mild injury characterized by diffusion tensor values, brain volumes, histological scores and behavioral parameters closer to sham. However, on average, melatonin treatment resulted only in a tendency towards milder injury on T₂-weighted MRI and apparent diffusion coefficient maps day 1 after HI, and not improved long-term outcome. These results indicate that the melatonin treatment regimen of 3 injections of 10 mg/kg within the first 25 hours only gave a transient and subtle neuroprotective effect, and may not have been sufficient to mitigate long-term brain injury development following HI.

Neuroprotection Strategies for Term Encephalopathy

Brain injury in the full-term and near-term neonates is a significant cause of mortality and long-term morbidity, resulting in injury patterns distinct from that seen in premature infants and older patients. Therapeutic hypothermia improves long-term outcomes for many of these infants, but there is a continued search for therapies to enhance the plasticity of the newborn brain, resulting in long-term repair. It is likely that a combination strategy utilizing both early and late interventions may have the most benefit, capitalizing on endogenous mechanisms triggered by hypoxia or ischemia. Optimizing care of these critically ill newborns in the acute setting is also vital for improving both short- and long-term outcomes.

Disrupted Visual Cortex Neurophysiology Following Very Preterm Birth

BACKGROUND

Visual regions develop rapidly in utero and throughout early childhood, but very preterm (VPT) birth can disrupt the typical maturation of primary cortices, with VPT children exhibiting mild visual impairments in early life and throughout development. This is thought to be due to dysfunctional maturation of occipital cortices. A way to readily index brain function is to examine neural oscillations; these mechanisms play a central role in the modeling and pruning of connections, providing an intrinsic temporal structure that refines the precise alignment of spiking, processing information in the brain, and coordinating networks.

METHODS

Using magnetoencephalography, we examined regional oscillatory patterns and functional coupling in VPT and full-term children. Five minutes of eyes-open resting-state data were acquired from 27 VPT and 32 full-term children at 8 years of age.

RESULTS

As hypothesized, the VPT group, when compared with control children, had elevated theta-band power, while alpha amplitude envelope coupling, a marker of connectivity, was found to be decreased.

CONCLUSIONS

These results support the hypothesis of spectral slowing in VPT children and more broadly suggest that the developmental arc of visual neurophysiology is disrupted by VPT birth. We conclude that these deficits underlie difficulties in complex visual perceptual processing evident during childhood and beyond.

Advanced nanotherapies to promote neuroregeneration in the injured newborn brain

Neonatal brain injury affects thousands of babies each year and may lead to long-term and permanent physical and neurological problems. Currently, therapeutic hypothermia is standard clinical care for term newborns with moderate to severe neonatal encephalopathy. Nevertheless, it is not completely protective, and additional strategies to restore and promote regeneration are urgently needed. One way to ensure recovery following injury to the immature brain is to augment endogenous regenerative pathways. However, novel strategies such as stem cell therapy, gene therapies and nanotechnology have not been adequately explored in this unique age group. In this perspective review, we describe current efforts that promote neuroprotection and potential targets that are unique to the developing brain, which can be leveraged to facilitate neuroregeneration.

Mild Neonatal Brain Hypoxia-Ischemia in Very Immature Rats Causes Long-Term Behavioral and Cerebellar Abnormalities at Adulthood

Systemic hypoxia-ischemia (HI) often occurs during preterm birth in human. HI induces injuries to hinder brain cells mainly in the ipsilateral forebrain structures. Such HI injuries may cause lifelong disturbances in the distant regions, such as the contralateral side of the cerebellum. We aimed to evaluate behavior associated with the cerebellum, to acquire cerebellar abundant metabolic alterations using in vivo 1H magnetic resonance spectroscopy (1H MRS), and to determine GFAP, NeuN, and MBP protein expression in the left cerebellum, in adult rats after mild early postnatal HI on the right forebrain at day 3 (PND3). From PND45, HI animals exhibited increased locomotion in the open field while there is neither asymmetrical forelimb use nor coordination deficits in the motor tasks. Despite the fact that metabolic differences between two cerebellar hemispheres were noticeable, a global increase in glutamine of HI rats was observed and became significant in the left cerebellum compared to the sham-operated group. Furthermore, increases in glutamate, glycine, the sum of glutamate and glutamine and total choline, only occurred in the left cerebellum of HI rats. Remarkably, there were decreased expression of MBP and NeuN but no detectable reactive astrogliosis in the contralateral side of the cerebellum of HI rats. Taken together, the detected alterations observed in the left cerebellum of HI rats may reflect disequilibrium in the glutamate-glutamine cycle and a delay in the return of glutamine from astrocytes to neurons from hypoxic-ischemic origin. Our data provides in vivo evidence of long-term changes in the corresponding cerebellum following mild neonatal HI in very immature rats, supporting the notion that systemic HI could cause cell death in the cerebellum, a distant region from the expected injury site.

HIGHLIGHTS

-Neonatal hypoxia-ischemia (HI) in very immature rats induces hyperactivity toward adulthood.-1H magnetic resonance spectroscopy detects long-term cerebellar metabolic changes in adult rats after neonatal HI at postnatal day 3.-Substantial decreases of expression of neuronal and myelin markers in adult rats cerebellum after neonatal cortical mild HI.

Oxidative Stress: A Key Modulator in Neurodegenerative Diseases

Oxidative stress is proposed as a regulatory element in ageing and various neurological disorders. The excess of oxidants causes a reduction of antioxidants, which in turn produce an oxidation-reduction imbalance in organisms. Paucity of the antioxidant system generates oxidative-stress, characterized by elevated levels of reactive species (oxygen, hydroxyl free radical, and so on). Mitochondria play a key role in ATP supply to cells via oxidative phosphorylation, as well as synthesis of essential biological molecules. Various redox reactions catalyzed by enzymes take place in the oxidative phosphorylation process. An inefficient oxidative phosphorylation may generate reactive oxygen species (ROS), leading to mitochondrial dysfunction. Mitochondrial redox metabolism, phospholipid metabolism, and proteolytic pathways are found to be the major and potential source of free radicals. A lower concentration of ROS is essential for normal cellular signaling, whereas the higher concentration and long-time exposure of ROS cause damage to cellular macromolecules such as DNA, lipids and proteins, ultimately resulting in necrosis and apoptotic cell death. Normal and proper functioning of the central nervous system (CNS) is entirely dependent on the chemical integrity of brain. It is well established that the brain consumes a large amount of oxygen and is highly rich in lipid content, becoming prone to oxidative stress. A high consumption of oxygen leads to excessive production of ROS. Apart from this, the neuronal membranes are found to be rich in polyunsaturated fatty acids, which are highly susceptible to ROS. Various neurodegenerative diseases such as Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), among others, can be the result of biochemical alteration (due to oxidative stress) in bimolecular components. There is a need to understand the processes and role of oxidative stress in neurodegenerative diseases. This review is an effort towards improving our understanding of the pivotal role played by OS in neurodegenerative disorders.

Rodent Models of Developmental Ischemic Stroke for Translational Research: Strengths and Weaknesses

Cerebral ischemia can occur at any stage in life, but clinical consequences greatly differ depending on the developmental stage of the affected brain structures. Timing of the lesion occurrence seems to be critical, as it strongly interferes with neuronal circuit development and determines the way spontaneous plasticity takes place. Translational stroke research requires the use of animal models as they represent a reliable tool to understand the pathogenic mechanisms underlying the generation, progression, and pathological consequences of a stroke. Moreover, in vivo experiments are instrumental to investigate new therapeutic strategies and the best temporal window of intervention. Differently from adults, very few models of the human developmental stroke have been characterized, and most of them have been established in rodents. The models currently used provide a better understanding of the molecular factors involved in the effects of ischemia; however, they still hold many limitations due to matching developmental stages across different species and the complexity of the human disorder that hardly can be described by segregated variables. In this review, we summarize the key factors contributing to neonatal brain vulnerability to ischemic strokes and we provide an overview of the advantages and limitations of the currently available models to recapitulate different aspects of the human developmental stroke.

Developmental Outcome in Infants with Cardiovascular Disease After Cardiopulmonary Resuscitation: A Pilot Study

Unfavorable neurological outcome in children after cardiopulmonary resuscitation in infancy is frequent. However, few studies have investigated the development of these patients using comprehensive developmental tests and the feasibility of the Bayley Scales of Infant Development, 3rd Edition (BSID-III) has not been reported for this population. In this cross-sectional pilot study, we assessed the cognitive, language, and motor development in infants after cardiopulmonary resuscitation of ≥ 5 min with the BSID-III at the age of 12 or 24 months, depending on recruitment age. For analysis, 11 patients with in-hospital (n = 8) and out-of-hospital (n = 3) cardiac arrest were included. BSID-III results could not be quantified in three patients because of visual/hearing and/or motor impairment. In patients with quantifiable scores, 50.0% scored average in composite BSID-III scores, while the other 50.0% showed developmental delays, scoring distinctly below average. We conclude that the BSID-III is feasible for developmental assessment in the majority of the study population, but the use of instruments suitable for hearing/visually impaired and/or severely disabled infants is crucial to avoid biased results. Accurate characterization of developmental deficits is important to facilitate early identification and therapy of deficits.

EEG sharp waves are a biomarker of striatal neuronal survival after hypoxia-ischemia in preterm fetal sheep

The timing of hypoxia-ischemia (HI) in preterm infants is often uncertain and there are few biomarkers to determine whether infants are in a treatable stage of injury. We evaluated whether epileptiform sharp waves recorded from the parietal cortex could provide early prediction of neuronal loss after HI. Preterm fetal sheep (0.7 gestation) underwent acute HI induced by complete umbilical cord occlusion for 25 minutes (n = 6) or sham occlusion (control, n = 6). Neuronal survival was assessed 7 days after HI by immunohistochemistry. Sharp waves were quantified manually and using a wavelet-type-2-fuzzy-logic-system during the first 4 hours of recovery. HI resulted in significant subcortical neuronal loss. Sharp waves counted by the automated classifier in the first 30 minutes after HI were associated with greater neuronal survival in the caudate nucleus (r = 0.80), whereas sharp waves between 2–4 hours after HI were associated with reduced neuronal survival (r = −0.83). Manual and automated counts were closely correlated. This study suggests that automated quantification of sharp waves may be useful for early assessment of HI injury in preterm infants. However, the pattern of evolution of sharp waves after HI was markedly affected by the severity of neuronal loss, and therefore early, continuous monitoring is essential.

THE EFFECT OF HYPOXIC BRAIN DAMAGE ON THE SURVIVAL OF PREMATURE INFANTS

The central nervous system injuries are a common neonatal pathology, hypoxia being one of the main causes of cerebral dysfunction. The purpose of this study was studying the incidence of hypoxic cerebral disorders in premature infants with an extremely low body weight and a very low birth weight and revealing the risk factors that adversely affected the disease outcome. The subject of the study was preterm infants whose gestational age did not exceed 31 weeks. The main criterion for inclusion into the study was the presence of hypoxic-ischemic and hypoxic-hemorrhagic brain damage. To reveal the perinatal risk factors, the somatic health of mothers, and pregnancy and childbirth peculiarities were studied. The structure of children’s pathology and intensive care techniques were analyzed. Cerebral disorders were verified in 42 out of 176 patients (23.5 %). 2–3rd-degree intraventricular hemorrhage was diagnosed in 34 newborns (80.9 %), severe ischemia in 8 children (19.1 %). To determine the structure of the disease outcome, all children were divided into deceased and survivors. A fatal outcome was observed in 14 cases (33.3 %). The mothers of deceased children were more likely to have obstetric and concomitant extragenital pathologies. Analysis of pediatric pathology showed that the hemodynamically significant functioning arterial duct and severe asphyxia in childbirth were much more frequent in deceased children. Intensive therapy of deceased children included «hard» parameters of artificial ventilation and high doses of cardiotonic drugs. Thus the presented risk factors can be considered as predictors of an unfavorable outcome in children with this pathology.

Thalamus Controls Development and Expression of Arousal States in Visual Cortex

Two major checkpoints of development in cerebral cortex are the acquisition of continuous spontaneous activity and the modulation of this activity by behavioral state. Despite the critical importance of these functions, the circuit mechanisms of their development remain unknown. Here we use the rodent visual system as a model to test the hypothesis that the locus of circuit change responsible for the developmental acquisition of continuity and state dependence measured in sensory cortex is relay thalamus, rather than the local cortical circuitry or the interconnectivity of the two structures. We conducted simultaneous recordings in the dorsal lateral geniculate nucleus (dLGN) and primary visual cortex (VC) of awake, head-fixed male and female rats using linear multielectrode arrays throughout early development. We find that activity in dLGN becomes continuous and positively correlated with movement (a measure of state dependence) on P13, the same day as VC, and that these properties are not dependent on VC activity. By contrast, silencing dLGN after P13 causes activity in VC to become discontinuous and movement to suppress, rather than augment, cortical firing, effectively reversing development. Thalamic bursting, a core characteristic of non-aroused states, emerged later, on P16, suggesting these processes are developmentally independent. Together our results indicate that cellular or circuit changes in relay thalamus are critical drivers for the maturation of background activity, which occurs around term in humans.SIGNIFICANCE STATEMENT The developing brain acquires two crucial features, continuous spontaneous activity and its modulation by arousal state, around term in humans and before the onset of sensory experience in rodents. This developmental transition in cortical activity, as measured by electroencephalogram (EEG), is an important milestone for normal brain development and indicates a good prognosis for babies born preterm and/or suffering brain damage such as hypoxic-ischemic encephalopathy. By using the awake rodent visual system as a model, we identify changes occurring at the level of relay thalamus, the major input to cortex, as the critical driver of EEG maturation. These results could help understand the circuit basis of human EEG development to improve diagnosis and treatment of infants in vulnerable situations.

Pseudobulbar Affect in Survivors of Extreme Prematurity With Cerebellar Injury: Support for the Cerebellar Link in Pathologic Laughter and Crying

Pseudobulbar affect, that is, pathologic laughter and crying is being increasingly recognized in adults and is seen in association with a number of diseases like Parkinson disease, dementia, traumatic encephalopathy, and others, but has not previously been described in children with cerebral palsy. The condition pseudobulbar affect may be due to lesions in (or degeneration of) the cerebro-ponto-cerebellar pathways. Here we report 2 children with cerebral palsy who have structural cerebellar injury because of their being born extremely premature who have pathologic crying and probably laughter.

Antenatal and Neonatal Antecedents of Executive Dysfunctions in Extremely Preterm Children

To find out why children born extremely preterm are at heightened risk of executive dysfunctions, the authors assessed 716 children who were 10 years old born extremely preterm whose IQ was ≥ 70. A working memory dysfunction (n = 169), an inhibition dysfunction (n = 360), a switching dysfunction (355), and all 3 (executive dysfunction; n = 107) were defined on the basis of Z-scores ≤ -1 on the Differential Ability Scales-II Working Memory composite, and/or on the NEPSY-II Inhibition-Inhibition and Inhibition-Switching subtests. All risk profiles include an indicator of socioeconomic disadvantage. The risk profile of each of the 3 individual dysfunctions includes an indicator of the newborn's immaturity, and the risk profiles of the inhibition dysfunction and switching dysfunction also include an indicator of inflammation. Only the switching dysfunction was associated with fetal growth restriction. The risk factors for executive dysfunction can be subsumed under the 4 themes of socioeconomic disadvantage, immaturity/vulnerability, inflammation, and fetal growth restriction.

MRI Changes in the Thalamus and Basal Ganglia of Full-Term Neonates with Perinatal Asphyxia

BACKGROUND

Magnetic resonance imaging (MRI) is the standard neuroimaging technique to assess perinatal asphyxia-associated brain injury in full-term infants. Diffusion-weighted imaging (DWI) is most informative when assessed during the first week after the insult.

OBJECTIVES

To study the DWI abnormalities of the thalamus and basal ganglia in full-term infants with perinatal asphyxia.

METHODS

Fifty-five (near) term infants (normothermia n = 23; hypothermia n = 32) with thalamus and/or basal ganglia injury were included. MRI findings were assessed visually and quantitatively calculating apparent diffusion coefficient (ADC) values. Thalamus/basal ganglia ADC ratios were calculated to analyze the differences between these areas. Infants with an early MRI (days 1-3) or later MRI (days 4-7) were compared.

RESULTS

Isolated extensive thalamic injury was seen early, and focal thalamic and basal ganglia injury was seen later. On the early MRI, visual assessment underestimated abnormalities in the basal ganglia (59% abnormal vs. 90% abnormal on quantitative assessment; p = 0.015), suggesting the need for quantitative assessment. In infants treated with hypothermia, the thalamus/basal ganglia ADC ratio was lower.

CONCLUSIONS

Both visual analysis and quantitative evaluation of cerebral MRI after perinatal asphyxia are needed, especially during the first few days after birth. Timing of ADC changes is influenced by therapeutic hypothermia.

Pretreatment with N-acetyl cysteine suppresses chronic reactive astrogliosis following maternal nanoparticle exposure during gestational period

Early pregnant employees are potentially and unintendedly exposed to industrial chemicals including nanoparticles. Developmental toxicity of nanoparticle exposure has been concerned because exposure to fine particle including carbon black nanoparticle (CB-NP) during the brain developmental stage enhances the risk of brain disorders. Maternal CB-NP exposure dose-dependently induces astrogliosis, which is an abnormal increase in the reactive astrocytes with glial fibrillary acidic protein (GFAP) and aquaporin-4 overexpression due to the destruction of nearby neurons and blood vessels. The present study aimed to investigate protective effects of antioxidants on the histopathological denaturation with astrogliosis following maternal CB-NP exposure in offspring mice, thereby to evaluate the role of oxidative stress on the developmental toxicity. Pregnant ICR mice were treated with CB-NP by intranasal instillation on gestational days 5 and 9. N-acetyl cysteine (NAC) or ascorbic acid was intraperitoneally administered to the pregnant mice 1 h prior to CB-NP instillation. The brains were collected from 6- to 12-week-old offspring mice and analyzed using western blotting and immunohistochemistry. NAC suppressed GFAP overexpression in 6- and 12-week-old offspring mice following maternal CB-NP exposure. However, NAC did not suppress aquaporin-4 overexpression following maternal CB-NP exposure. Ascorbic acid did not suppress, but rather slightly and significantly enhanced the expression of GFAP and aquaporin-4. These results indicate that astrogliosis by maternal CB-NP exposure is partially prevented by NAC pretreatment. Oxidative stress is a possible key factor of developmental neurotoxicity of maternal NP exposure. This study will contribute to elucidating the mechanisms underlying the effects of developmental neurotoxicity of NPs.

A preliminary evaluation of glial cell line-derived neurotrophic factor (GDNF) levels in cerebrospinal fluid across various gestational ages and clinical conditions of the neonate

BACKGROUND

This study aims to investigate glial cell derived neurotrophic factor (GDNF) levels in newborns' umbilical cord blood and cerebrospinal fluid across various perinatal growth parameters and clinical conditions.

METHODS

Cord blood from 20 newborns and 58 residual CSF samples (stored after completion of clinical testing) were collected. GDNF levels were determined using GDNF ELISA kits from R&D Systems in triplicates with appropriate controls to eliminate background.

RESULTS

Cord blood GDNF levels were significantly higher (p=0.004) in preterm newborns (n=6) (115.05±57.17,pg/ml) when compared to term newborns (n=14) (19.67±10.67,pg/ml). GDNF levels in CSF trended (p=0.07) higher in term newborns (n=10) (19.56±9.11,pg/ml) when compared to preterm newborns at term or post term corrected gestational ages (n=5) (14.49±3.53,pg/ml).

CONCLUSIONS

GDNF levels in preterm newborns were higher in cord blood and lower in CSF as compared to term newborns. It is important to further study circulating and CSF-GDNF levels in newborns at different gestational ages and clinical conditions.

Effects of therapeutic hypothermia on white matter injury from murine neonatal hypoxia-ischemia

BackgroundTherapeutic hypothermia (TH) is the standard of care for neonates with hypoxic-ischemic encephalopathy, but it is not fully protective in the clinical setting. Hypoxia-ischemia (HI) may cause white matter injury (WMI), leading to neurological and cognitive dysfunction.MethodsP9 mice were subjected to HI as previously described. Pups underwent 3.5 h of systemic hypothermia or normothermia. Cresyl violet and Perl's iron staining for histopathological scoring of brain sections was completed blindly on all brains. Immunocytochemical (ICC) staining for myelin basic protein (MBP), microglia (Iba1), and astrocytes (glia fibrillary acidic protein (GFAP)) was performed on adjacent sections. Volumetric measurements of MBP coverage were used for quantitative analysis of white matter.ResultsTH provided neuroprotection by injury scoring for the entire group (n=44; P<0.0002). ICC analysis of a subset of brains showed that the lateral caudate was protected from WMI (P<0.05). Analysis revealed decreased GFAP and Iba1 staining in hippocampal regions, mostly CA2/CA3. GFAP and Iba1 directly correlated with injury scores of normothermic brains.ConclusionTH reduced injury, and qualitative data suggest that hippocampus and lateral caudate are protected from HI. Mildly injured brains may better show the benefits of TH. Overall, these data indicate regional differences in WMI susceptibility and inflammation in a P9 murine HI model.

The novel cannabinoid receptor GPR55 mediates anxiolytic-like effects in the medial orbital cortex of mice with acute stress

The G protein-coupled receptor 55 (GPR55) is a novel cannabinoid receptor, whose exact role in anxiety remains unknown. The present study was conducted to explore the possible mechanisms by which GPR55 regulates anxiety and to evaluate the effectiveness of O-1602 in the treatment of anxiety-like symptoms. Mice were exposed to two types of acute stressors: restraint and forced swimming. Anxiety behavior was evaluated using the elevated plus maze and the open field test. We found that O-1602 alleviated anxiety-like behavior in acutely stressed mice. We used lentiviral shRNA to selective ly knockdown GPR55 in the medial orbital cortex and found that knockdown of GPR55 abolished the anxiolytic effect of O-1602. We also used Y-27632, a specific inhibitor of ROCK, and U73122, an inhibitor of PLC, and found that both inhibitors attenuated the effectiveness of O-1602. Western blot analysis revealed that O-1602 downregulated the expression of GluA1 and GluN2A in mice. Taken together, these results suggest that GPR55 plays an important role in anxiety and O-1602 may have therapeutic potential in treating anxiety-like symptoms.

Neurovascular toxicity of N-methyl-d-aspartate is markedly enhanced in the developing mouse central nervous system

Penumbral perfusion is critical to brain viability. Proximal arterial occlusion and deep brain stroke has variable effect on cortical dysfunction. Cortical microvessel collaterals may be recruited and at times sufficient for partial parenchymal perfusion. Postnatal neural and endothelial cells are markedly vulnerable to glutamate excitotoxicity. Early vascular cell stress may promote partial protective neural preconditioning though postnatally a developmental window of the cerebral microvasculature may be particularly vulnerable to injury. We tested the hypothesis that postnatal NMDA excitotoxic injury, when cerebral endothelial cells' central energy source is via glycolysis, is age specific. Neurovascular responses of cortical viability were directly identified with diffuse reflectance patterns of perfusion properties in a non-invasive manner, over time. Histological evaluation for neural and vascular cytoarchitectonic abnormalities were evaluated 4- 7days post injury. Optical diffuse reflectance recordings were obtained at the injection site prior to, immediately after and 48h post injury. Extent of neurovascular injury at the infarct zone was greatest at PND 5 and cortical perfusion responses identified with recordings of pattern change. These data further suggest excitotoxic injury to both neural and vascular cells, in vivo, can enhance CNS injury in the young and neuroprotective strategies may benefit from vascular directed therapies.

Neuroprotection in Schizophrenia and Its Therapeutic Implications

Schizophrenia is a chronic and debilitating mental disorder. The persisting negative and cognitive symptoms that are unresponsive to pharmacotherapy reveal the impairment of neuroprotective aspects of schizophrenia. In this review, of the several neuroprotective factors, we mainly focused on neuroinflammation, neurogenesis, and oxidative stress. We conducted a narrative and selective review. Neuroinflammation is mainly mediated by pro-inflammatory cytokines and microglia. Unlike peripheral inflammatory responses, neuroinflammation has a role in various neuronal activities such as neurotransmission neurogenesis. The cross-talk between neuroinflammation and neurogenesis usually has beneficial effects in the CNS under physiological conditions. However, uncontrolled and chronic neuroinflammation exert detrimental effects such as neuronal loss, inhibited neurogenesis, and excessive oxidative stress. Neurogenesis is also a major component of neuroprotection. Adult neurogenesis mainly occurs in the hippocampal region, which has an important role in memory formation and processing. Impaired neurogenesis and an ineffective response to antipsychotics may be thought to indicate a deteriorating course of schizophrenia. Oxidative stress and excessive dopaminergic neurotransmission may create a vicious cycle and consequently disturb NMDA receptor-mediated glutamatergic neurotransmission. Based on the current evidences, several neuroprotective therapeutic approaches have been reported to be efficacious for improving psychopathology, but further longitudinal and large-sample based studies are needed.

Neonatal Hypoxia Ischaemia: Mechanisms, Models, and Therapeutic Challenges

Neonatal hypoxia-ischaemia (HI) is the most common cause of death and disability in human neonates, and is often associated with persistent motor, sensory, and cognitive impairment. Improved intensive care technology has increased survival without preventing neurological disorder, increasing morbidity throughout the adult population. Early preventative or neuroprotective interventions have the potential to rescue brain development in neonates, yet only one therapeutic intervention is currently licensed for use in developed countries. Recent investigations of the transient cortical layer known as subplate, especially regarding subplate's secretory role, opens up a novel set of potential molecular modulators of neonatal HI injury. This review examines the biological mechanisms of human neonatal HI, discusses evidence for the relevance of subplate-secreted molecules to this condition, and evaluates available animal models. Neuroserpin, a neuronally released neuroprotective factor, is discussed as a case study for developing new potential pharmacological interventions for use post-ischaemic injury.

Dose-dependent induction of astrocyte activation and reactive astrogliosis in mouse brain following maternal exposure to carbon black nanoparticle

Background

Recent studies indicate that maternal exposure to ambient ultrafine particles and nanoparticles has adverse effects of on the central nervous system. Quantitative dose–response data is required to better understand the developmental neurotoxicity of nanoparticles. The present study investigated dose-dependent effects of maternal exposure to carbon black nanoparticle (CB-NP) on astrocyte in the brains of mouse offspring.

Methods

A CB-NP suspension (2.9, 15, or 73 μg/kg) was intranasally administered to pregnant ICR mice on gestational days 5 and 9. Cerebral cortex samples were collected from 6-week-old offspring and examined by Western blotting, immunostaining, microarray analysis, and quantitative reverse transcriptase-polymerase chain reaction. Placentae were collected from pregnant dams on gestational day 13 and examined by microarray analysis.

Results

Maternal exposure to CB-NP induced a dose-dependent increase in glial fibrillary acidic protein (GFAP) expression in the cerebral cortex; this increase was particularly observed in astrocytic end-feet attached to denatured perivascular macrophages. Moreover, maternal CB-NP exposure dose-dependently increased aquaporin-4 expression in the brain parenchyma region around blood vessels. The changes in the expression profiles of GFAP and Aqp4 in offspring after maternal CB-NP exposure were similar to those observed in mice of a more advanced age. The expression levels of mRNAs associated with angiogenesis, cell migration, proliferation, chemotaxis, and growth factor production were also altered in the cerebral cortex of offspring after maternal CB-NP exposure. Differentially expressed genes in placental tissues after CB-NP exposure did not populate any specific gene ontology category.

Conclusions

Maternal CB-NP exposure induced long-term activation of astrocytes resulting in reactive astrogliosis in the brains of young mice. Our observations suggest a potentially increased risk of the onset of age-related neurodegenerative diseases by maternal NP exposure. In this study, we report for the first time a quantitative dose–response relationship between maternal NP exposure and phenotypic changes in the central nervous system of the offspring. Moreover, our findings indicate that cortical GFAP and Aqp4 are useful biomarkers that can be employed in further studies aiming to elucidate the underlying mechanism of nanoparticle-mediated developmental neurotoxicity.