Perinatal brain damage: The term infant

Regulated cell death in hypoxic-ischaemic encephalopathy: recent development and mechanistic overview

Hypoxic-ischaemic encephalopathy (HIE) in termed infants remains a significant cause of morbidity and mortality worldwide despite the introduction of therapeutic hypothermia. Depending on the cell type, cellular context, metabolic predisposition and insult severity, cell death in the injured immature brain can be highly heterogenous. A continuum of cell death exists in the H/I-injured immature brain. Aside from apoptosis, emerging evidence supports the pathological activation of necroptosis, pyroptosis and ferroptosis as alternative regulated cell death (RCD) in HIE to trigger neuroinflammation and metabolic disturbances in addition to cell loss. Upregulation of autophagy and mitophagy in HIE represents an intrinsic neuroprotective strategy. Molecular crosstalk between RCD pathways implies one RCD mechanism may compensate for the loss of function of another. Moreover, mitochondrion was identified as the signalling "hub" where different RCD pathways converge. The highly-orchestrated nature of RCD makes them promising therapeutic targets. Better understanding of RCD mechanisms and crosstalk between RCD subtypes likely shed light on novel therapy development for HIE. The identification of a potential RCD converging node may open up the opportunity for simultaneous and synergistic inhibition of cell death in the immature brain.

Plasmatic profiles of cytokines/chemokines, glial fibrillary acidic protein (GFAP) and MRI brain damage in neonates with hypoxic ischemic encephalopathy (HIE)

BACKGROUND

Perinatal hypoxia triggers the release of cytokines and chemokines by neurons, astrocytes and microglia. In response to hypoxia-ischemia resting/ramified microglia proliferate and undergo activation, producing proinflammatory molecules. The brain damage extension seems to be related to both the severity of hypoxia and the balance between pro and anti-inflammatory response and can be explored with neuroimaging.

AIMS

The aim of this preliminary study was to explore possible relationships between plasma levels of inflammatory cytokines/chemokines and the severe brain damage detectable by Magnetic Resonance Imaging (MRI), performed during the hospitalization.

METHODS

In 10 full terms neonates with hypoxic ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH), divided into cases and controls, according to MRI results, we measured and compared the plasma levels of CCL2/MCP-1, CXCL8, GFAP, IFN y, IL-10, IL-18, IL-6, CCL3, ENOLASE2, GM-CSF, IL-1b, IL-12p70, IL-33, TNFα, collected at four different time points during TH (24, 25-48, 49-72 h of life, and 7-10 days from birth). Five of enrolled babies had pathological brain MRI (cases) and 5 had a normal MRI examination (controls). Cytokines were measured by Magnetic Luminex Assay. MRI images were classified according to Barkovich's score.

RESULTS

Mean levels of all cytokines and molecules at time T1 were not significantly different in the two groups. Comparing samples paired by day of collection, the greatest differences between cases and controls were found at times T2 and T3, during TH. At T4, levels tended to get closer again (except for IL-6, IL10 and IL18). Infants with worse MRI showed higher plasmatic GFAP levels than those with normal MRI, while their IL-18 was lower. The mean levels of CCL3MIP1alpha, GMCSF, IL1BETA overlapped throughout the observation period in both groups.

CONCLUSION

In a small number of infants with worse brain MRI, we found higher levels of GFAP and of IL-10 at T4 and a trend toward low IL-18 levels than in infants with normal MRI, considered early biomarker of brain damage and a predictor of adverse outcome, respectively. The greatest, although not significant, difference between the levels of molecules was found in cases and controls at time points T2 and T3, during TH.

Stability of the Motor Optimality Score Revised (MOS-R) in medically complex infants

BACKGROUND

The Motor Optimality Score-Revised (MOS-R) is a clinical test of infant spontaneous movement at 3-5 months of age and has been associated with neurodevelopmental outcomes in infants with medical complexity. However the stability of the MOS-R tested at different developmental ages is not yet known.

AIM

To determine if the repeated scoring of the MOS-R remained consistent when tested at two developmental ages in young infants.

STUDY DESIGN

In this prospective cohort study, infants were tested twice with the MOS-R between 12 and 13 weeks corrected age (CA) and 14-16 weeks CA. Bland Altman Plots were used to calculate agreement between the scores. Infants were grouped as having higher or lower medical complexity. MOS-R threshold scores were analyzed to assess changes over time within each group using Fisher's exact test.

SUBJECTS

85 infants with history of hospitalization in a neonatal intensive care unit (NICU).

RESULTS

The MOS-R scores had a high agreement with negligible bias (0.058) between timepoints (95 % CI -1.10, 1.22). Using a MOS-R cut point of 19, infants with higher medical complexity were more likely to change groups between timepoints than infants with lower medical complexity (p = 0.008), but this was not significantly different using cut points of 20 or 21.

CONCLUSION

The MOS-R scores were stable when measured repeatedly in infants who were hospitalized in a NICU. Infants with high medical complexity had less stable MOS-R scores using certain cut points than infants with lower medical complexity.

Clinical-functional correlation with brain volumetry in severe perinatal asphyxia: a case report

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) appears in neurological conditions where some brain areas are likely to be injured, such as deep grey matter, basal ganglia area, and white matter subcortical periventricular áreas. Moreover, modeling these brain areas in a newborn is challenging due to significant variability in the intensities associated with HIE conditions. This paper aims to evaluate functional measurements and 3D machine learning models of a given HIE case by correlating the affected brain areas with the pathophysiology and clinical neurodevelopmental.

CASE PRESENTATION

A comprehensive analysis of a term infant with perinatal asphyxia using longitudinal 3D brain information from Machine Learning Models is presented. The clinical analysis revealed the perinatal asphyxia diagnosis with APGAR <5 at 5 and 10 minutes, umbilical arterial pH of 7.0 BE of -21.2 mmol / L), neonatal seizures, and invasive ventilation mechanics. Therapeutic interventions: physical, occupational, and language neurodevelopmental therapies. Epilepsy treatment: vagus nerve stimulation, levetiracetam, and phenobarbital. Furthermore, the 3D analysis showed how the volume decreases due to age, exhibiting an increasing asymmetry between hemispheres. The results of the basal ganglia area showed that thalamus asymmetry, caudate, and putamen increase over time while globus pallidus decreases.

CLINICAL OUTCOMES

spastic cerebral palsy, microcephaly, treatment-refractory epilepsy.

CONCLUSIONS

Slight changes in the basal ganglia and cerebellum require 3D volumetry for detection, as standard MRI examinations cannot fully reveal their complex shape variations. Quantifying these subtle neurodevelopmental changes helps in understanding their clinical implications. Besides, neurophysiological evaluations can boost neuroplasticity in children with neurological sequelae by stimulating new neuronal connections.

Blood and CSF levels of brain-derived neurotrophic factor in patients with encephalopathy/encephalitis: a systematic review and meta-analysis

BACKGROUND

Brain-derived neurotrophic factor (BDNF) is critical for enhancing the survival and growth of neurons and modulating the synaptic plasticity. BDNF levels have been demonstrated to be changed in plasma and cerebrospinal fluid (CSF) following brain insults such as inflammation or ischemia or infection in several studies. Currently, there is no systematic review regarding BDNF levels in encephalitis or encephalopathy patients. Considering inconsistency between studies, we aimed to pool the data from existing studies to determine whether blood or CSF levels of BDNF are different in patients with encephalopathy/encephalitis.

METHODS

We comprehensively searched Web of Science, PubMed, Scopus, and Embase databases to identify eligible studies. The last search occurred in December 2022.

RESULTS

12 studies met our inclusion criteria and ten studies including 283 patients and 323 healthy controls were enrolled in this meta-analysis. In comparison to controls, patients with encephalitis/encephalopathy had higher levels of BDNF in their CSF [standardized mean difference (SMD) = 1.48, 95% CI 0.18-2.77; P = 0.03)], while their blood levels of BDNF did not differ significantly [standardized mean difference (SMD) = 0.27, 95% CI = - 0.71 to 1.25; P = 0.58)]. Moreover, regarding the heterogeneity among studies reporting BDNF blood levels, we performed two subgroup analyses based on the disease etiology and the specimen (plasma and serum); none of them indicated statistically significant difference in BDNF levels between the subgroups (P = 0.41 and 0.20, respectively).

CONCLUSION

Meta-analysis provides evidence that patients with encephalopathy/encephalitis have higher CSF levels of BDNF compared to controls.

Brain Maturation as a Fundamental Factor in Immune-Neurovascular Interactions in Stroke

Injuries in the developing brain cause significant long-term neurological deficits. Emerging clinical and preclinical data have demonstrated that the pathophysiology of neonatal and childhood stroke share similar mechanisms that regulate brain damage, but also have distinct molecular signatures and cellular pathways. The focus of this review is on two different diseases-neonatal and childhood stroke-with emphasis on similarities and distinctions identified thus far in rodent models of these diseases. This includes the susceptibility of distinct cell types to brain injury with particular emphasis on the role of resident and peripheral immune populations in modulating stroke outcome. Furthermore, we discuss some of the most recent and relevant findings in relation to the immune-neurovascular crosstalk and how the influence of inflammatory mediators is dependent on specific brain maturation stages. Finally, we comment on the current state of treatments geared toward inducing neuroprotection and promoting brain repair after injury and highlight that future prophylactic and therapeutic strategies for stroke should be age-specific and consider gender differences in order to achieve optimal translational success.

Intranasal insulin attenuates hypoxia-ischemia-induced short-term sensorimotor behavioral disturbances, neuronal apoptosis, and brain damage in neonatal rats

There is a significant need for additional therapy to improve outcomes for newborns with acute Hypoxic-ischemic (HI) encephalopathy (HIE). New evidence suggests that insulin could be neuroprotective. This study aimed to investigate whether intranasal insulin attenuates HI-induced brain damage and neurobehavioral dysfunction in neonatal rats. Postnatal day 10 (P10), Sprague-Dawley rat pups were randomly divided into Sham + Vehicle, Sham + Insulin, HI + Vehicle, and HI + Insulin groups with equal male-to-female ratios. Pups either had HI by permanent ligation of the right common carotid artery followed by 90 min of hypoxia (8% O2) or sham surgery followed by room air exposure. Immediately after HI or Sham, pups were given fluorescence-tagged insulin (Alex-546-insulin)/vehicle, human insulin (25 μg), or vehicle in each nare under anesthesia. Shortly after administration, widespread Alex-546-insulin-binding cells were detected in the brain, primarily co-localized with neuronal nuclei-positive neurons on double-immunostaining. In the hippocampus, phospho-Akt was activated in a subset of Alex-546-insulin double-labeled cells, suggesting activation of the Akt/PI3K pathway in these neurons. Intranasal insulin (InInsulin) reduced HI-induced sensorimotor behavioral disturbances at P11. InInsulin prevented HI-induced increased Fluoro-Jade C+ degenerated neurons, cleaved caspase 3+ neurons, and volume loss in the ipsilateral brain at P11. There was no sex-specific response to HI or insulin. The findings confirm that intranasal insulin provides neuroprotection against HI brain injury in P10 rats associated with activation of intracellular cell survival signaling. If further pre-clinical research shows long-term benefits, intranasal insulin has the potential to be a promising non-invasive therapy to improve outcomes for newborns with HIE.

Effect of maternal serum magnesium and calcium levels on umbilical glial fibrillary acidic protein levels in preterm labor

Magnesium can prevent astrocyte cell death and Glial Fibrillary Acidic Protein (GFAP) secretion as inflammatory marker in preterm delivery. This study was performed to analyze differences in umbilical cord GFAP levels in preterm labor given magnesium sulfate (MgSO4) as treatment group and control group and analyze the correlation between magnesium and calcium levels with umbilical GFAP levels. This quasi-experimental study was performed on 68 patients at Dr. Hasan Sadikin General Hospital from February-June 2021 consisting of 34 patients in each group. Maternal-umbilical cord magnesium levels, calcium levels, and GFAP levels were examined using ELISA test. The result was statistically measured by IBM SPSS 24.0. We found that there was a significant difference between maternal and umbilical magnesium levels and GFAP umbilical cord blood levels between the treatment and the control group (P < 0.05) in which GFAP level was higher in the control group. The multivariate analysis showed no significant relevance between mother magnesium and calcium level to umbilical cord GFAP level in the MgSO4 group. As conclusions, umbilical cord blood GFAP levels in preterm labor given MgSO4 were lower than in preterm deliveries who were not given MgSO4. There was no correlation between magnesium, calcium, and GFAP levels in the treatment group.

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

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

Capsaicin attenuates excitotoxic-induced neonatal brain injury and brain mast cell-mediated neuroinflammation in newborn rats

Excitotoxicity and neuroinflammation are key contributors to perinatal brain injuries. Capsaicin, an active ingredient of chili peppers, is a potent exogenous agonist for transient receptor potential vanilloid 1 receptors. Although the neuroprotective and anti-inflammatory effects of capsaicin are well-documented, its effects on excitotoxic-induced neonatal brain injury and neuroinflammation have not previously been investigated. The aim of this study was to investigate the effects of capsaicin on brain damage, brain mast cells, and inflammatory mediators in a model of ibotenate-induced excitotoxic brain injury in neonatal rats. P5 rat-pups were intraperitoneally injected with vehicle, 0.2-, 1-, and 5-mg/kg doses of capsaicin, or the NMDA (N-methyl-d-aspartate) receptor antagonist MK-801 (dizocilpine), 30 min before intracerebral injection of 10 μg ibotenate. The naive-control group received no substance administration. The rat pups were sacrificed one or five days after ibotenate injection. Levels of activin A and interleukin (IL)-1β, IL-6, and IL-10 in brain tissue were measured using the enzyme-linked immunosorbent assay method. Cortex and white matter thicknesses, white matter lesion size, and mast cells were evaluated in brain sections stained with cresyl-violet or toluidine-blue. Capsaicin improved ibotenate-induced white matter lesions and cerebral white and gray matter thicknesses in a dose-dependent manner. In addition, it suppressed the degranulation and increased number of brain mast cells induced by ibotenate. Capsaicin also reduced the excitotoxic-induced production of neuronal survival factor activin A and of the pro-inflammatory cytokines IL-1β, and IL-6 in brain tissue. However, IL-10 levels were not altered by the treatments. MK-801, as a positive control, reversed all these ibotenate-induced changes, further confirming the success of the model. Our findings provide, for the first time, evidence for the therapeutic effects of capsaicin against excitotoxic-induced neonatal brain injury and brain mast cell-mediated neuroinflammation. Capsaicin may therefore be a promising candidate in the prevention and/or reduction of neonatal brain damage.

Stem cell programming - prospects for perinatal medicine

Recreating human cell and organ systems in vitro has tremendous potential for disease modeling, drug discovery and regenerative medicine. The aim of this short overview is to recapitulate the impressive progress that has been made in the fast-developing field of cell programming during the past years, to illuminate the advantages and limitations of the various cell programming technologies for addressing nervous system disorders and to gauge their impact for perinatal medicine.

Necroptosis Blockade Potentiates the Neuroprotective Effect of Hypothermia in Neonatal Hypoxic-Ischemic Encephalopathy

Neonatal encephalopathy (NE) caused by hypoxia-ischemia (HI) affects around 1 per 1000 term newborns and is the leading cause of acquired brain injury and neurodisability. Despite the use of hypothermia (HT) as a standard of care, the incidence of NE and its devastating outcomes remains a major issue. Ongoing research surrounding add-on neuroprotective strategies against NE is important as HT effects are limited, leaving 50% of treated patients with neurological sequelae. Little is known about the interaction between necroptotic blockade and HT in neonatal HI. Using a preclinical Lewis rat model of term human NE induced by HI, we showed a neuroprotective effect of Necrostatin-1 (Nec-1: a compound blocking necroptosis) in combination with HT. The beneficial effect of Nec-1 added to HT against NE injuries was observed at the mechanistic level on both pMLKL and TNF-α, and at the anatomical level on brain volume loss visualized by magnetic resonance imaging (MRI). HT alone showed no effect on activated necroptotic effectors and did not preserve the brain MRI volume. This study opens new avenues of research to understand better the specific cell death mechanisms of brain injuries as well as the potential use of new therapeutics targeting the necroptosis pathway.

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

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

The Role of Music Therapy with Infants with Perinatal Brain Injury

Perinatal brain injury occurs in 5.14/1000 live births in England. A significant proportion of these injuries result from hypoxic ischaemic encephalopathy (HIE) in term infants and intracranial haemorrhage (IVH) or periventricular leukomalacia (PVL) in preterm infants. Standardised care necessitates minimal handling from parents and professionals to reduce the progression of injury. This can potentially increase parental stress through the physical inability to bond with their baby. Recent research highlights the ability of music therapy (MT) to empower parental bonding without handling, through sharing culturally informed personal music with their infant. This review therefore aimed to systematically evaluate the use of MT with infants diagnosed with perinatal brain injury in a neonatal intensive care unit (NICU). Search terms were combined into three categories (audio stimulation (MT), population (neonates) and condition (brain injury), and eight electronic databases were used to identify relevant studies following PRISMA guidelines. Eleven studies using music or vocal stimulation with infants diagnosed with perinatal brain injury were identified and quality assessed using Cochrane ROB2, the ROBINSI Tool and the Newcastle Ottawa Scale. Studies used either voice as live (n = 6) or pre-recorded (n = 3) interventions or pre-recorded instrumental music (n = 2). Studies had two primary areas of focus: developmental outcomes and physiological effects. Results suggested the use of music interventions led to a reduction of infants' pain scores during procedures and cardiorespiratory events, improved feeding ability (increase oral feeding rate, volume intake and feeds per day) and resulted in larger amygdala volumes than control groups. Additionally, MT intervention on the unit supported long-term hospitalised infants in the acquisition of developmental milestones. Vocal soothing was perceived to be an accessible intervention for parents. However, infants with PVL showed signs of stress in complex interventions, which also potentially resulted in an increase in maternal anxiety in one study. MT with infants diagnosed with perinatal brain injury can have positive effects on infants' behavioural and neurological parameters and support parental involvement in their infants' developmental care. Further feasibility studies are required using MT to determine appropriate outcome measures for infants and the support required for parents to allow future comparison in large-scale randomised control trials.

CeRebrUm and CardIac Protection with ALlopurinol in Neonates with Critical Congenital Heart Disease Requiring Cardiac Surgery with Cardiopulmonary Bypass (CRUCIAL): study protocol of a phase III, randomized, quadruple-blinded, placebo-controlled, Dutch multicenter trial

Background

Neonates with critical congenital heart disease (CCHD) undergoing cardiac surgery with cardiopulmonary bypass (CPB) are at risk of brain injury that may result in adverse neurodevelopment. To date, no therapy is available to improve long-term neurodevelopmental outcomes of CCHD neonates. Allopurinol, a xanthine oxidase inhibitor, prevents the formation of reactive oxygen and nitrogen species, thereby limiting cell damage during reperfusion and reoxygenation to the brain and heart. Animal and neonatal studies suggest that allopurinol reduces hypoxic-ischemic brain injury and is cardioprotective and safe. This trial aims to test the hypothesis that allopurinol administration in CCHD neonates will result in a 20% reduction in moderate to severe ischemic and hemorrhagic brain injury.

Methods

This is a phase III, randomized, quadruple-blinded, placebo-controlled, multicenter trial. Neonates with a prenatal or postnatal CCHD diagnosis requiring cardiac surgery with CPB in the first 4 weeks after birth are eligible to participate. Allopurinol or mannitol-placebo will be administered intravenously in 2 doses early postnatally in neonates diagnosed antenatally and 3 doses perioperatively of 20 mg/kg each in all neonates. The primary outcome is a composite endpoint of moderate/severe ischemic or hemorrhagic brain injury on early postoperative MRI, being too unstable for postoperative MRI, or mortality within 1 month following CPB. A total of 236 patients (n = 188 with prenatal diagnosis) is required to demonstrate a reduction of the primary outcome incidence by 20% in the prenatal group and by 9% in the postnatal group (power 80%; overall type 1 error controlled at 5%, two-sided), including 1 interim analysis at n = 118 (n = 94 with prenatal diagnosis) with the option to stop early for efficacy. Secondary outcomes include preoperative and postoperative brain injury severity, white matter injury volume (MRI), and cardiac function (echocardiography); postnatal and postoperative seizure activity (aEEG) and regional cerebral oxygen saturation (NIRS); neurodevelopment at 3 months (general movements); motor, cognitive, and language development and quality of life at 24 months; and safety and cost-effectiveness of allopurinol.

Discussion

This trial will investigate whether allopurinol administered directly after birth and around cardiac surgery reduces moderate/severe ischemic and hemorrhagic brain injury and improves cardiac function and neurodevelopmental outcome in CCHD neonates.

Trial registration

EudraCT 2017-004596-31. Registered on November 14, 2017. ClinicalTrials.gov NCT04217421. Registered on January 3, 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06098-y.

C3a Receptor Signaling Inhibits Neurodegeneration Induced by Neonatal Hypoxic-Ischemic Brain Injury

Hypoxic-ischemic neonatal encephalopathy due to perinatal asphyxia is the leading cause of brain injury in newborns. Clinical data suggest that brain inflammation induced by perinatal insults can persist for years. We previously showed that signaling through the receptor for complement peptide C3a (C3aR) protects against cognitive impairment induced by experimental perinatal asphyxia. To investigate the long-term neuropathological effects of hypoxic-ischemic injury to the developing brain and the role of C3aR signaling therein, we subjected wildtype mice, C3aR deficient mice, and mice expressing biologically active C3a in the CNS to mild hypoxic-ischemic brain injury on postnatal day 9. We found that such injury triggers neurodegeneration and pronounced reactive gliosis in the ipsilesional hippocampus both of which persist long into adulthood. Transgenic expression of C3a in reactive astrocytes reduced hippocampal neurodegeneration and reactive gliosis. In contrast, neurodegeneration and microglial cell density increased in mice lacking C3aR. Intranasal administration of C3a for 3 days starting 1 h after induction of hypoxia-ischemia reduced neurodegeneration and reactive gliosis in the hippocampus of wildtype mice. We conclude that neonatal hypoxic-ischemic brain injury leads to long-lasting neurodegeneration. This neurodegeneration is substantially reduced by treatment with C3aR agonists, conceivably through modulation of reactive gliosis.

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.

BMP-6 Attenuates Oxygen and Glucose Deprivation-Induced Apoptosis in Human Neural Stem Cells through Inhibiting p38 MAPK Signaling Pathway

Background and Objectives

Neural stem cells (NSCs) remain in the mammalian brain throughout life and provide a novel therapeutic strategy for central nervous system (CNS) injury. Bone morphogenetic protein-6 (BMP-6) had shown a protective effect in different types of cells. However, the role of BMP-6 in NSCs is largely unclear. The present study was aimed to investigate whether BMP-6 could protect human NSCs (hNSCs) against the oxygen and glucose deprivation (OGD)-induced cell death.

Methods and Results

Upon challenge with OGD treatment, cell viability was significantly decreased in a time-dependent manner, as indicated by the CCK-8 assay. BMP-6 could attenuate the OGD-induced cell injury in a dose-dependent manner and decrease the number of TUNEL-positive cells. Moreover, BMP-6 markedly weakened the OGD-induced alterations in the expression of procaspase-8/9/3 and reversed the expression of cleaved-caspase-3. Interestingly, noggin protein (the BMP-6 inhibitor) attenuated the neuroprotective effect of BMP-6 in cultured hNSCs. Furthermore, the p38 MAPK signaling pathway was activated by OGD treatment and BMP-6 markedly inhibited the phosphorylation of p38 in a concentration-dependent manner. Pretreatment with noggin abolished the effect of BMP-6 on p38 activation. SB239063, a selective p38 inhibitor, exerted similar effects with BMP-6 in protecting hNSCs against the OGD-induced apoptosis. These results indicated that blocking the phosphorylation of p38 might contribute to the neuroprotective effect of BMP-6 against the OGD-induced injury in hNSCs.

Conclusions

These findings suggested that BMP-6 might be a therapeutic target in the OGD-induced cell death, which provides a novel therapeutic strategy for enhancing host and graft NSCs survival in hypoxic-ischemic brain injury.

Cortical Visual Impairment in Childhood: 'Blindsight' and the Sprague Effect Revisited

The paper discusses and provides support for diverse processes of brain plasticity in visual function after damage in infancy and childhood in comparison with injury that occurs in the adult brain. We provide support and description of neuroplastic mechanisms in childhood that do not seemingly exist in the same way in the adult brain. Examples include the ability to foster the development of thalamocortical connectivities that can circumvent the lesion and reach their cortical destination in the occipital cortex as the developing brain is more efficient in building new connections. Supporting this claim is the fact that in those with central visual field defects we can note that the extrastriatal visual connectivities are greater when a lesion occurs earlier in life as opposed to in the neurologically mature adult. The result is a significantly more optimized system of visual and spatial exploration within the ‘blind’ field of view. The discussion is provided within the context of “blindsight” and the “Sprague Effect”.

Apoptosis and necroptosis occur in the different brain regions of hippocampus in a rat model of hypoxia asphyxia

AIM OF THE STUDY

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain injury. Apoptosis and necroptosis are two forms of cell death which may occur in HIE but reported data are yet limited. This study investigates the expression of receptor interacting protein kinase (RIPK) 1 and 3, and caspase3, the key modulators of necroptosis and apoptosis, respectively, in a model of HIE to determine whether both forms of cell death occur in the corresponding brain regions.

MATERIALS AND METHODS

Postneonatal day 7 Sprague-Dawley rats were subjected to right carotid artery ligation followed by hypoxia or subjected to skin incision under surgical anesthesia without ligation and hypoxia. Neuroglioma (H4) cell was cultured and subjected to 24 h hypoxic insults. Necrostatin-1, a RIPK1 inhibitor, was administered in both in vivo and in vitro settings before insult.

RESULTS

After hypoxic-ischemic insults, both RIPK1 and RIPK3 expression were significantly increased in the region of hippocampal dentate gyrus in the injurious hemisphere. However, cleaved caspase3 was significantly increased in the hippocampal cornu ammonis 1 region in the injurious hemisphere. After hypoxic insults, RIPK1 and RIPK3 expression was also found in H4 cells. In addition, it was identified that the increased RIPK1 and RIPK3 can be inhibited by necrostatin-1 in both in vivo and in vitro.

CONCLUSIONS

These data indicated that apoptosis and necroptosis occur in different brain regions of hippocampus in a model of HIE which may suggest that strategies to prevent each form of neuronal death is valuable to be developed.

Traumatic Injury to the Developing Brain: Emerging Relationship to Early Life Stress

Despite the high incidence of brain injuries in children, we have yet to fully understand the unique vulnerability of a young brain to an injury and key determinants of long-term recovery. Here we consider how early life stress may influence recovery after an early age brain injury. Studies of early life stress alone reveal persistent structural and functional impairments at adulthood. We consider the interacting pathologies imposed by early life stress and subsequent brain injuries during early brain development as well as at adulthood. This review outlines how early life stress primes the immune cells of the brain and periphery to elicit a heightened response to injury. While the focus of this review is on early age traumatic brain injuries, there is also a consideration of preclinical models of neonatal hypoxia and stroke, as each further speaks to the vulnerability of the brain and reinforces those characteristics that are common across each of these injuries. Lastly, we identify a common mechanistic trend; namely, early life stress worsens outcomes independent of its temporal proximity to a brain injury.

The Complement System: A Powerful Modulator and Effector of Astrocyte Function in the Healthy and Diseased Central Nervous System

The complement system, an effector arm of the innate immune system that plays a critical role in tissue inflammation, the elimination of pathogens and the clearance of dead cells and cell debris, has emerged as a regulator of many processes in the central nervous system, including neural cell genesis and migration, control of synapse number and function, and modulation of glial cell responses. Complement dysfunction has also been put forward as a major contributor to neurological disease. Astrocytes are neuroectoderm-derived glial cells that maintain water and ionic homeostasis, and control cerebral blood flow and multiple aspects of neuronal functioning. By virtue of their expression of soluble as well as membrane-bound complement proteins and receptors, astrocytes are able to both send and receive complement-related signals. Here we review the current understanding of the multiple functions of the complement system in the central nervous system as they pertain to the modulation of astrocyte activity, and how astrocytes use the complement system to affect their environment in the healthy brain and in the context of neurological disease.

Fetal Neuroprotective Strategies: Therapeutic Agents and Their Underlying Synaptic Pathways

Synaptic signaling is integral for proper brain function. During fetal development, exposure to inflammation or mild hypoxic-ischemic insult may lead to synaptic changes and neurological damage that impairs future brain function. Preterm neonates are most susceptible to these deleterious outcomes. Evaluating clinically used and novel fetal neuroprotective measures is essential for expanding treatment options to mitigate the short and long-term consequences of fetal brain injury. Magnesium sulfate is a clinical fetal neuroprotective agent utilized in cases of imminent preterm birth. By blocking N-methyl-D-aspartate receptors, magnesium sulfate reduces glutamatergic signaling, which alters calcium influx, leading to a decrease in excitotoxicity. Emerging evidence suggests that melatonin and N-acetyl-L-cysteine (NAC) may also serve as novel putative fetal neuroprotective candidates. Melatonin has important anti-inflammatory and antioxidant properties and is a known mediator of synaptic plasticity and neuronal generation. While NAC acts as an antioxidant and a precursor to glutathione, it also modulates the glutamate system. Glutamate excitotoxicity and dysregulation can induce perinatal preterm brain injury through damage to maturing oligodendrocytes and neurons. The improved drug efficacy and delivery of the dendrimer-bound NAC conjugate provides an opportunity for enhanced pharmacological intervention. Here, we review recent literature on the synaptic pathways underlying these therapeutic strategies, discuss the current gaps in knowledge, and propose future directions for the field of fetal neuroprotective agents.

Epilepsy-Related Outcomes in Children With Neonatal Cerebellar Injury

OBJECTIVE

Acute brain injury is a frequent perinatal neurologic complication that can involve the cerebellum. Although short-term outcomes of infants with neonatal cerebellar injury are well described, neurologic sequelae in older children are underreported. Here, we describe epilepsy-related outcomes in young children who suffered from neonatal cerebellar injuries.

METHODS

In-house automated software identified patients with neonatal brain injuries who were evaluated at our institution both as neonates (≤28 days) and as children (≥1 year). Neonatal hospital course, neuroimaging, and outcomes related to epilepsy were reviewed from the medical record. Patients were stratified into 2 groups based on neonatal brain injuries: those with cerebellar injury and those without cerebellar involvement.

RESULTS

Of the 282 neonates followed through childhood over the decade-long study period, 33 (12%) experienced neonatal brain injury. All 33 cases involved supratentorial injury, and 5 (15%) also included cerebellar injury. The development of epilepsy was significantly less likely in the group with cerebellar involvement (40%) compared to that with cerebellar sparing (82%; P = 0.043). In some cases, children with cerebellum-sparing injuries required admission for seizure control and developed drug-resistant epilepsy as well as status epilepticus. These outcomes occurred less frequently in the group with cerebellar involvement.

CONCLUSIONS

Epilepsy-related sequelae may occur less frequently when the cerebellum is involved in neonatal brain injury. Larger prospective studies are needed to clarify how cerebellocortical networks impact functional brain connectivity and epilepsy longitudinally.

The clinical effects of cerebral near-infrared spectroscopy monitoring (NIRS) versus no monitoring: a protocol for a systematic review with meta-analysis and trial sequential analysis

BACKGROUND

Multiple clinical conditions are associated with cerebral hypoxia/ischaemia and thereby an increased risk of hypoxic-ischaemic brain injury. Cerebral near-infrared spectroscopy monitoring (NIRS) is a tool to monitor brain oxygenation and perfusion, and the clinical uptake of NIRS has expanded over recent years. Specifically, NIRS is used in the neonatal, paediatric, and adult perioperative and intensive care settings. However, the available literature suggests that clinical benefits and harms of cerebral NIRS monitoring are uncertain. As rates of clinically significant hypoxic-ischaemic brain injuries are typically low, it is difficult for randomised clinical trials to capture a sufficiently large number of events to evaluate the clinical effect of cerebral NIRS monitoring, when focusing on specific clinical settings. The aim of this systematic review will be to evaluate the benefits and harms of clinical care with access to cerebral NIRS monitoring versus clinical care without cerebral NIRS monitoring in children and adults across all clinical settings.

METHODS

We will conduct a systematic review with meta-analysis and trial sequential analysis. We will only include randomised clinical trials. The primary outcomes are all-cause mortality, moderate or severe persistent cognitive or neurological deficit, and proportion of participants with one or more serious adverse events. We will search CENTRAL, EMBASE, MEDLINE, and the Science Citation Index Expanded from their inception and onwards. Two reviewers will independently screen all citations, full-text articles, and extract data. The risk of bias will be appraised using the Cochrane risk of bias tool version 2.0. If feasible, we will conduct both random-effects meta-analysis and fixed-effect meta-analysis of outcome data. Additional analysis will be conducted to explore the potential sources of heterogeneity (e.g. risk of bias, clinical setting).

DISCUSSION

As we include trials across multiple clinical settings, there is an increased probability of reaching a sufficient information size. However, heterogeneity between the included trials may impair our ability to interpret results to specific clinical settings. In this situation, we may have to depend on subgroup analyses with inherent increased risks of type I and II errors.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020202986 . This systematic review protocol has been submitted for registration in the International Prospective Register of Systematic Reviews (PROSPERO) (http://www.crd.york.ac.uk/prospero) on the 12th of October 2020 and published on the 12th of November 2020 (registration ID CRD42020202986 ).

Resting-state brain networks in neonatal hypoxic-ischemic brain damage: a functional near-infrared spectroscopy study

Significance: There is an emerging need for convenient and continuous bedside monitoring of full-term newborns with hypoxic-ischemic brain damage (HIBD) to determine whether early intervention is required. Functional near-infrared spectroscopy (fNIRS)-based resting-state brain network analysis, which could provide an effective evaluation method, remains to be extensively studied. Aim: Our study aims to verify the feasibility of fNIRS-based resting-state brain networks for evaluating brain function in infants with HIBD to provide a new and effective means for clinical research in neonatal HIBD. Approach: Thirteen neonates with HIBD were scanned using fNIRS in the resting state. The brain network properties were explored to attempt to extract effective features as recognition indicators. Results: Compared with healthy controls, newborns with HIBD showed decreased brain functional connectivity. Specifically, there were severe losses of long-range functional connectivity of the contralateral parietal-temporal lobe, contralateral parietal-frontal lobe, and contralateral parietal lobe. The node degree showed a widespread decrease in the left frontal middle gyrus, left superior frontal gyrus dorsal, and right central posterior gyrus. However, newborns with HIBD showed a significantly higher local network efficiency (* p < 0.05 ). Subsequently, network indicators based on small-worldness, local efficiency, modularity, and normalized clustering coefficient were extracted for HIBD identification with the accuracy observed as 79.17%. Conclusions: Our findings indicate that fNIRS-based resting-state brain network analysis could support early HIBD diagnosis.

Neonatal Encephalopathy: Beyond Hypoxic-Ischemic Encephalopathy

Neonatal encephalopathy is a clinical syndrome of neurologic dysfunction that encompasses a broad spectrum of symptoms and severity, from mild irritability and feeding difficulties to coma and seizures. It is vital for providers to understand that the term "neonatal encephalopathy" is simply a description of the neonate's neurologic status that is agnostic to the underlying etiology. Unfortunately, hypoxic-ischemic encephalopathy (HIE) has become common vernacular to describe any neonate with encephalopathy, but this can be misleading. The term should not be used unless there is evidence of perinatal asphyxia as the primary cause of encephalopathy. HIE is a common cause of neonatal encephalopathy; the differential diagnosis also includes conditions with infectious, vascular, epileptic, genetic/congenital, metabolic, and toxic causes. Because neonatal encephalopathy is estimated to affect 2 to 6 per 1,000 term births, of which HIE accounts for approximately 1.5 per 1,000 term births, (1)(2)(3)(4)(5)(6) neonatologists and child neurologists should familiarize themselves with the evaluation, diagnosis, and treatment of the diverse causes of neonatal encephalopathy. This review begins by discussing HIE, but also helps practitioners extend the differential to consider the broad array of other causes of neonatal encephalopathy, emphasizing the epidemiology, neurologic presentations, diagnostics, imaging findings, and therapeutic strategies for each potential category.

Bedside functional monitoring of the dynamic brain connectivity in human neonates

Clinicians have long been interested in functional brain monitoring, as reversible functional losses often precedes observable irreversible structural insults. By characterizing neonatal functional cerebral networks, resting-state functional connectivity is envisioned to provide early markers of cognitive impairments. Here we present a pioneering bedside deep brain resting-state functional connectivity imaging at 250-μm resolution on human neonates using functional ultrasound. Signal correlations between cerebral regions unveil interhemispheric connectivity in very preterm newborns. Furthermore, fine-grain correlations between homologous pixels are consistent with white/grey matter organization. Finally, dynamic resting-state connectivity reveals a significant occurrence decrease of thalamo-cortical networks for very preterm neonates as compared to control term newborns. The same method also shows abnormal patterns in a congenital seizure disorder case compared with the control group. These results pave the way to infants' brain continuous monitoring and may enable the identification of abnormal brain development at the bedside.

Therapeutic potential of stem cells for preterm infant brain damage: Can we move from the heterogeneity of preclinical and clinical studies to established therapeutics?

Acquired perinatal brain injuries are a set of conditions that remains a key challenge for neonatologists and that have significant social, emotional and financial implications for our communities. In our perspective article, we will introduce perinatal brain injury focusing specifically on the events leading to brain damage in preterm born infants and outcomes for these infants. Then we will summarize and discuss the preclinical and clinical studies testing the efficacy of stem cells as neuroprotectants in the last ten years in perinatal brain injury. There are no therapies to treat brain damage in preterm born infants and a primary finding from this review is that there is a scarcity of stem cell trials focused on overcoming brain injuries in these infants. Overall, across all forms of perinatal brain injury there is a remarkable heterogeneity in previous and on-going preclinical and clinical studies in terms of the stem cell type, animal models/patient selection, route and time of administration. Despite the quality of many of the studies this variation makes it difficult to reach a valid consensus for future developments. However, it is clear that stem cells (and stem cell derived exosomes) can reduce perinatal brain injury and our field needs to work collectively to refine an effective protocol for each type of injury. The use of standardized stem cell products and testing these products across multiple models of injury will provide a stronger framework for clinical trials development.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Role of apoptosis-inducing factor in perinatal hypoxic-ischemic brain injury

Perinatal complications, such as asphyxia, can cause brain injuries that are often associated with subsequent neurological deficits, such as cerebral palsy or mental retardation. The mechanisms of perinatal brain injury are not fully understood, but mitochondria play a prominent role not only due to their central function in metabolism but also because many proteins with apoptosis-related functions are located in the mitochondrion. Among these proteins, apoptosis-inducing factor has already been shown to be an important factor involved in neuronal cell death upon hypoxia-ischemia, but a better understanding of the mechanisms behind these processes is required for the development of more effective treatments during the early stages of perinatal brain injury. In this review, we focus on the molecular mechanisms of hypoxic-ischemic encephalopathy, specifically on the importance of apoptosis-inducing factor. The relevance of apoptosis-inducing factor is based not only because it participates in the caspase-independent apoptotic pathway but also because it plays a crucial role in mitochondrial energetic functionality, especially with regard to the maintenance of electron transport during oxidative phosphorylation and in oxidative stress, acting as a free radical scavenger. We also discuss all the different apoptosis-inducing factor isoforms discovered, focusing especially on apoptosis-inducing factor 2, which is only expressed in the brain and the functions of which are starting now to be clarified. Finally, we summarized the interaction of apoptosis-inducing factor with several proteins that are crucial for both apoptosis-inducing factor functions (pro-survival and pro-apoptotic) and that are highly important in order to develop promising therapeutic targets for improving outcomes after perinatal brain injury.

Neonatal hypoxic-ischemic brain injury leads to sex-specific deficits in rearing and climbing in adult mice

The study examined the morphological and long-term behavioral impacts of neonatal hypoxic-ischemic brain injury in a mouse model. We investigated the modification of different behavioral domains, such as spontaneous climbing, which represents fine motor skills. We also focused on sex-dependent differences during hypoxic-ischemic encephalopathy. The Rice-Vannucci model of hypoxia-ischemia was used, adjusted and adapted to 7-day-old C57BL/6NTac mice. The effects of induced hypoxia and ischemia were also studied separately. At postnatal day 60, mice underwent behavioral testing using the LABORAS apparatus. The perfusion for histological evaluation was performed one day after the behavioral analyses. In groups with separately induced hypoxia or ischemia, the observed alterations in behavior were not accompanied by morphological changes in the cortex or hippocampal formation. Female mice naturally climbed significantly more and hypoxic females reared less than hypoxic males (p<0.05). Male mice postnatally exposed to hypoxia-ischemia exhibited significantly lower vertical activity and higher horizontal activity (p<0.05). Mild hypoxic damage may not be morphologically detectable but may induce substantial behavioral changes in adult mice. There were significant differences between horizontal and vertical activity in reaction to hypoxia-ischemia. Our study indicates that the importance of behavioral testing is irreplaceable and may be reflected in neonatal medicine.

Applications of functional near-infrared spectroscopy (fNIRS) in neonates

Functional near-infrared spectroscopy (fNIRS) is a method of monitoring brain oxygenation. This technique investigates hemodynamic changes in the cerebral cortex. fNIRS is widely used in clinical and scientific research. In this review, we focus on the applications of fNIRS on neonates. Here, applications form two distinct categories: task associated studies, and hemoglobin phase change studies. fNIRS is non-invasive, easily performed, and repeatable. However, it has limited monitoring depth and spatial resolution when used in newborns. Moreover, with recent technological advances, it is now possible to explore neuronal activity patterns using fNIRS in both healthy and pathological conditions. For more than 20 years, fNIRS has enabled clinicians to gain insight into cerebral development and mechanisms of injury in neonates. fNIRS is a useful supplement to existing technologies due to its ability to interrogate the neonatal brain function.

[Modern non-drug technologies for medical rehabilitation of children with consequences of perinatal affection of the central nervous system]

The article is devoted to the issues of medical rehabilitation of children with consequences of perinatal affection of the central nervous system (CNS). An important and principal aspect of the medical rehabilitation of children with perinatal pathology is the minimization of drugs, in this regard, in children in the first year of life, the leading role is given to non-drug methods of exposure. Among the important challenges of the medical rehabilitation of children with perinatal pathology are: improvement of blood supply and metabolic processes in the brain tissue, normalization of the central and peripheral regulation of muscle tone, improvement of neuromuscular conduction, stimulation of psychomotor development. In this case, kinesitherapy technologies are of leading importance: massotherapy, therapeutic exercises, reflex kinesitherapy according to V. Vojta; fitball gymnastics, method of fine finger training, dry floatation, etc. Along with physical rehabilitation methods, physiotherapy methods are actively used, which makes it possible to increase the effectiveness of treatment. The analysis of the literature showed that the use of modern non-drug technologies in children with perinatal CNS pathology, and their introduction into practice can significantly increase the effectiveness of medical rehabilitation of such children.

Midkine: The Who, What, Where, and When of a Promising Neurotrophic Therapy for Perinatal Brain Injury

Midkine (MK) is a small secreted heparin-binding protein highly expressed during embryonic/fetal development which, through interactions with multiple cell surface receptors promotes growth through effects on cell proliferation, migration, and differentiation. MK is upregulated in the adult central nervous system (CNS) after multiple types of experimental injury and has neuroprotective and neuroregenerative properties. The potential for MK as a therapy for developmental brain injury is largely unknown. This review discusses what is known of MK's expression and actions in the developing brain, areas for future research, and the potential for using MK as a therapeutic agent to ameliorate the effects of brain damage caused by insults such as birth-related hypoxia and inflammation.

Long-term therapeutic effects of Katona therapy in moderate-to-severe perinatal brain damage

AIM

To determine the long-term efficacy of Katona therapy and early rehabilitation of infants with moderate-to-severe perinatal brain damage (PBD).

METHODS

Thirty-two participants were recruited (7-16 years) and divided into 3 groups: one Healthy group (n = 11), one group with PBD treated with Katona methodology from 2 months of corrected age, and with long-term follow-up (n = 12), and one group with PBD but without treatment in the first year of life due to late diagnosis of PBD (n = 9). Neuropediatric evaluations, motor evoked potentials (MEPs) and magnetic resonance images (MRI) were made. The PBD groups were matched by severity and topography of lesion.

RESULTS

The patients treated with Katona had better motor performance when compared to patients without early treatment (Gross Motor Function Classification System levels; 75% of Katona group were classified in levels I and II and 78% of patients without early treatment were classified in levels III and IV). Furthermore, independent k-means cluster analyses of MRI, MEPs, and neuropediatric evaluations data were performed. Katona and non-treated early groups were classified in the same MRI cluster which is the expected for PBD population patients. However, in MEPs and neuropediatric evaluations clustering, the 67% of Katona group were assigned into Healthy group showing the impact of Katona therapy over the patients treated with it. These results highlight the Katona therapy benefits in early rehabilitation of infants with moderate-to-severe PBD.

CONCLUSIONS

Katona therapy and early rehabilitation have an important therapeutic effect in infants with moderate-to-severe PBD by decreasing the severity of motor disability in later stages of life.

Preterm birth and sustained inflammation: consequences for the neonate

Almost half of all preterm births are caused or triggered by an inflammatory process at the feto-maternal interface resulting in preterm labor or rupture of membranes with or without chorioamnionitis (“first inflammatory hit”). Preterm babies have highly vulnerable body surfaces and immature organ systems. They are postnatally confronted with a drastically altered antigen exposure including hospital-specific microbes, artificial devices, drugs, nutritional antigens, and hypoxia or hyperoxia (“second inflammatory hit”). This is of particular importance to extremely preterm infants born before 28 weeks, as they have not experienced important “third-trimester” adaptation processes to tolerate maternal and self-antigens. Instead of a balanced adaptation to extrauterine life, the delicate co-regulation between immune defense mechanisms and immunosuppression (tolerance) to allow microbiome establishment is therefore often disturbed. Hence, preterm infants are predisposed to sepsis but also to several injurious conditions that can contribute to the onset or perpetuation of sustained inflammation (SI). This is a continuing challenge to clinicians involved in the care of preterm infants, as SI is regarded as a crucial mediator for mortality and the development of morbidities in preterm infants. This review will outline the (i) role of inflammation for short-term consequences of preterm birth and (ii) the effect of SI on organ development and long-term outcome.

Neuroprotective Effects of Diabetes Drugs for the Treatment of Neonatal Hypoxia-Ischemia Encephalopathy

The perinatal period represents a time of great vulnerability for the developing brain. A variety of injuries can result in death or devastating injury causing profound neurocognitive deficits. Hypoxic-ischemic neonatal encephalopathy (HIE) remains the leading cause of brain injury in term infants during the perinatal period with limited options available to aid in recovery. It can result in long-term devastating consequences with neurologic complications varying from mild behavioral deficits to severe seizure, intellectual disability, and/or cerebral palsy in the newborn. Despite medical advances, the only viable option is therapeutic hypothermia which is classified as the gold standard but is not used, or may not be as effective in preterm cases, infection-associated cases or low resource settings. Therefore, alternatives or adjunct therapies are urgently needed. Ongoing research continues to advance our understanding of the mechanisms contributing to perinatal brain injury and identify new targets and treatments. Drugs used for the treatment of patients with type 2 diabetes mellitus (T2DM) have demonstrated neuroprotective properties and therapeutic efficacy from neurological sequelae following HIE insults in preclinical models, both alone, or in combination with induced hypothermia. In this short review, we have focused on recent findings on the use of diabetes drugs that provide a neuroprotective effect using in vitro and in vivo models of HIE that could be considered for clinical translation as a promising treatment.

Inhibiting the interaction between apoptosis-inducing factor and cyclophilin A prevents brain injury in neonatal mice after hypoxia-ischemia

The interaction between apoptosis-inducing factor (AIF) and cyclophilin A (CypA) has been shown to contribute to caspase-independent apoptosis. Blocking the AIF/CypA interaction protects against glutamate-induced neuronal cell death in vitro, and the purpose of this study was to determine the in vivo effect of an AIF/CypA interaction blocking peptide (AIF(370-394)-TAT) on neonatal mouse brain injury after hypoxia-ischemia (HI). The pups were treated with AIF (370-394)-TAT peptide intranasally prior to HI. Brain injury was significantly reduced at 72 h after HI in the AIF(370-394)-TAT peptide treatment group compared to vehicle-only treatment for both the gray matter and the subcortical white matter, and the neuroprotection was more pronounced in males than in females. Neuronal cell death was evaluated in males at 8 h and 24 h post-HI, and it was decreased significantly in the CA1 region of the hippocampus and the nucleus habenularis region after AIF(370-394)-TAT treatment. Caspase-independent apoptosis was decreased in the cortex, striatum, and nucleus habenularis after AIF(370-394)-TAT treatment, but no significant change was found on caspase-dependent apoptosis as indicated by the number of active caspase-3-labeled cells. Further analysis showed that both AIF and CypA nuclear accumulation were decreased after treatment with the AIF(370-394)-TAT peptide. These results suggest that AIF(370-394)-TAT inhibited AIF/CypA translocation to the nucleus and reduced HI-induced caspase-independent apoptosis and brain injury in young male mice, suggesting that blocking AIF/CypA might be a potential therapeutic target for neonatal brain injury.

Methylprednisolone Reduces Persistent Post-ischemic Inflammation in a Rat Hypoxia-Ischemia Model of Perinatal Stroke

In perinatal stroke, the initial injury results in a chronic inflammatory response caused by the release of proinflammatory cytokines, gliosis and microglia activation. This chronic and ongoing inflammatory response exacerbates the brain injury, often resulting in encephalopathy and cerebral palsy (CP). Using a neonatal rat model of hypoxia-ischemia (HI) at postnatal day (P)7, we demonstrated that chronic inflammation is persistent and continues into the tertiary phase of perinatal stroke and can be attenuated by the administration of methylprednisolone sodium-succinate (MPSS, 30 mg/kg), a US Food and Drug Administration (FDA) approved anti-inflammatory agent. The inflammatory response was assessed by real-time quantitative PCR and ELISA for markers of inflammation (CCL3, CCL5, IL18 and TNFα). Structural changes were evaluated by histology (LFB/H&E), while cellular changes were assessed by Iba-1, ED1, GFAP, NeuN, Olig2 and CC1 immunostaining. Functional deficits were assessed with the Cylinder test and Ladder Rung Walking test. MPSS was injected 14 days after HI insult to attenuate chronic inflammation. In neonatal conditions such as CP, P21 is a clinically relevant time-point in rodents, corresponding developmentally to a 2-year-old human. Administration of MPSS resulted in reduced structural damage (corpus callosum, cortex, hippocampus, striatum), gliosis and reactive microglia and partial restoration of the oligodendrocyte population. Furthermore, significant behavioural recovery was observed. In conclusion, we demonstrated that administration of MPSS during the tertiary phase of perinatal stroke results in attenuation of the chronic inflammatory response, leading to pathophysiological and functional recovery. This work validates the high clinical impact of MPSS to treat neonatal conditions linked to chronic inflammation.

Pharmacokinetics and short-term safety of the selective NOS inhibitor 2-iminobiotin in asphyxiated neonates treated with therapeutic hypothermia

BACKGROUND

Neonatal encephalopathy following perinatal asphyxia is a leading cause for neonatal death and disability, despite treatment with therapeutic hypothermia. 2-Iminobiotin is a promising neuroprotective agent additional to therapeutic hypothermia to improve the outcome of these neonates.

METHODS

In an open-label study, pharmacokinetics and short-term safety of 2-iminobiotin were investigated in neonates treated with therapeutic hypothermia. Group A (n = 6) received four doses of 0.16 mg/kg intravenously q6h. Blood sampling for pharmacokinetic analysis and monitoring of vital signs for short-term safety analysis were performed. Data from group A was used to determine the dose for group B, aiming at an AUC_0-48 h of 4800 ng*h/mL.

RESULTS

Exposure in group A was higher than targeted (median AUC_0-48 h 9522 ng*h/mL); subsequently, group B (n = 6) received eight doses of 0.08 mg/kg q6h (median AUC_0-48 h 4465 ng*h/mL). No changes in vital signs were observed and no adverse events related to 2-iminobiotin occurred.

CONCLUSION

This study indicates that 2-iminobiotin is well tolerated and not associated with any adverse events in neonates treated with therapeutic hypothermia after perinatal asphyxia. Target exposure was achieved with eight doses of 0.08 mg/kg q6h. Optimal duration of therapy for clinical efficacy needs to be determined in future clinical trials.

GM1 Ganglioside Is A Key Factor in Maintaining the Mammalian Neuronal Functions Avoiding Neurodegeneration

Many species of ganglioside GM1, differing for the sialic acid and ceramide content, have been characterized and their physico-chemical properties have been studied in detail since 1963. Scientists were immediately attracted to the GM1 molecule and have carried on an ever-increasing number of studies to understand its binding properties and its neurotrophic and neuroprotective role. GM1 displays a well balanced amphiphilic behavior that allows to establish strong both hydrophobic and hydrophilic interactions. The peculiar structure of GM1 reduces the fluidity of the plasma membrane which implies a retention and enrichment of the ganglioside in specific membrane domains called lipid rafts. The dynamism of the GM1 oligosaccharide head allows it to assume different conformations and, in this way, to interact through hydrogen or ionic bonds with a wide range of membrane receptors as well as with extracellular ligands. After more than 60 years of studies, it is a milestone that GM1 is one of the main actors in determining the neuronal functions that allows humans to have an intellectual life. The progressive reduction of its biosynthesis along the lifespan is being considered as one of the causes underlying neuronal loss in aged people and severe neuronal decline in neurodegenerative diseases. In this review, we report on the main knowledge on ganglioside GM1, with an emphasis on the recent discoveries about its bioactive component.

Closed circuit xenon delivery for 72h in neonatal piglets following hypoxic insult using an ambient pressure automated control system: Development, technical evaluation and pulmonary effects

BACKGROUND

Therapeutic hypothermia (TH) for 72h is the standard treatment following neonatal encephalopathy (NE). However, one-third do not benefit and adjunctive therapies are urgently needed. Xenon enhances neuroprotection with TH when administered at 50% concentration within 5hours of hypoxia in experimental studies. Delayed initiation (~10 hours of age) of 30% xenon for 24 hours during TH did not improve early adverse biomarkers in a clinical trial of Xenon+TH vs TH. After hypoxia-ischemia, excitotoxic injury via N-methyl-D-aspartate receptor overactivation lasts days. Since xenon partially inhibits this receptor, we hypothesised that giving 50% xenon throughout the entire 72h TH and rewarming periods would enhance neuroprotection. Xenon costs $30/litre, so a closed-circuit breathing system is desirable with automated fresh gas delivery.

METHODS

Seven mechanically ventilated newborn pigs were randomized to receive 50% inhaled xenon for 72h during hypothermia (rectal-temperature 35°C) and subsequent rewarming following a global hypoxic-ischemic insult (XeHT, N = 4) or under normothermia for 72h (rectal-temperature 38.5°C) following sham insult (XeNT, N = 3). An automated fresh gas delivery system injected oxygen/air/xenon boluses into a closed-circuit based on measured gas concentrations.

RESULTS AND DISCUSSION

Median (IQR) xenon consumption was 0.31 L/h (0.18, 0.50) and 0.34L/h (0.32, 0.49) for hypothermic and normothermic groups respectively, 0.34L/h (0.25, 0.53) overall. 92% of 9626 xenon and 69% of 9635 oxygen measurements were within 20% variation from targets. For xenon concentration, the median absolute performance errors for the XeHT and XeNT groups were 6.14% and 3.84% respectively and 4.31% overall. For oxygen these values were 13.42%, 15.05% and 12.4% respectively. There were no adverse pulmonary pathophysiology findings. Clinical problems over the total period included three related to sensors, seven breathing system leaks, ten partial and one complete tracheal tube occlusion episodes.

CONCLUSION

The automated controller functioned as intended maintaining an inhaled xenon concentration close to the 50% target for 72-78h at a xenon cost of $11.1/h.

Decreased body temperature during anoxia affects the endogenous BDNF level in tertiary phase of injury

Asphyxia before, during, or after birth is an important cause of perinatal mortality and morbidity. The mechanism underlying neurological damage resulting from anoxia episode is complex and is not limited to the anoxia episode. Although the benefits of therapeutic hypothermia in secondary failure of oxidative metabolism have long been known, the principle of this therapy in tertiary phase of repair and reorganization have not yet to be fully elucidated. Currently brain-derived neurotrophic factor (BDNF) is also considered to be beneficial to neuronal survival. Therefore, our experiments aimed at determining the effects of low body temperature during simulated perinatal anoxia on the level of the neurotrophic brain-derived factor (BDNF) and on the correlation between the level of BDNF (proBDNF and mBDNF) and the level of active caspase-3 (marker of apoptosis) in developing brain in tertiary phase after exposure. The results demonstrated that the ability of BDNF to inhibit caspase-3 activation and subsequent apoptosis likely accounts in large part for its protection against neuronal damage only in rats maintaining the low body temperature.

The Role of Mitochondrial and Endoplasmic Reticulum Reactive Oxygen Species Production in Models of Perinatal Brain Injury

Significance: Perinatal brain injury is caused by hypoxia-ischemia (HI) in term neonates, perinatal arterial stroke, and infection/inflammation leading to devastating long-term neurodevelopmental deficits. Therapeutic hypothermia is the only currently available treatment but is not successful in more than 50% of term neonates suffering from hypoxic-ischemic encephalopathy. Thus, there is an urgent unmet need for alternative or adjunct therapies. Reactive oxygen species (ROS) are important for physiological signaling, however, their overproduction/accumulation from mitochondria and endoplasmic reticulum (ER) during HI aggravate cell death. Recent Advances and Critical Issues: Mechanisms underlying ER stress-associated ROS production have been primarily elucidated using either non-neuronal cells or adult neurodegenerative experimental models. Findings from mature brain cannot be simply transferred to the immature brain. Therefore, age-specific studies investigating ER stress modulators may help investigate ER stress-associated ROS pathways in the immature brain. New therapeutics such as mitochondrial site-specific ROS inhibitors that selectively inhibit superoxide (O2•-)/hydrogen peroxide (H2O2) production are currently being developed. Future Directions: Because ER stress and oxidative stress accentuate each other, a combinatorial therapy utilizing both antioxidants and ER stress inhibitors may prove to be more protective against perinatal brain injury. Moreover, multiple relevant targets need to be identified for targeting ROS before they are formed. The role of organelle-specific ROS in brain repair needs investigation. Antioxid. Redox Signal. 31, 643-663.

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.

Sex differences in neonatal mouse brain injury after hypoxia-ischemia and adaptaquin treatment

Hypoxia-inducible factor prolyl 4-hydroxylases (HIF-PHDs) are important targets against oxidative stress. We hypothesized that inhibition HIF-PHD by adaptaquin reduces hypoxic-ischemic brain injury in a neonatal mouse model. The pups were treated intraperitoneally immediately with adaptaquin after hypoxia-ischemia (HI) and then every 24 h for 3 days. Adaptaquin treatment reduced infarction volume by an average of 26.3% at 72 h after HI compared to vehicle alone, and this reduction was more pronounced in males (34.8%) than in females (11.7%). The protection was also more pronounced in the cortex. The subcortical white matter injury as measured by tissue loss volume was reduced by 24.4% in the adaptaquin treatment group, and this reduction was also more pronounced in males (28.4%) than in females (18.9%). Cell death was decreased in the cortex as indicated by Fluoro-Jade labeling, but not in other brain regions with adaptaquin treatment. Furthermore, in the brain injury area, adaptaquin did not alter the number of cells positive for caspase-3 activation or translocation of apoptosis-inducing factor to the nuclei. Adaptaquin treatment increased glutathione peroxidase 4 mRNA expression in the cortex but had no impact on 3-nitrotyrosine, 8-hydroxy-2 deoxyguanosine, or malondialdehyde production. Hif1α mRNA expression increased after HI, and adaptaquin treatment also stimulated Hif1α mRNA expression, which was also more pronounced in males than in females. However, nuclear translocation of HIF1α protein was decreased after HI, and adaptaquin treatment had no influence on HIF1α expression in the nucleus. These findings demonstrate that adaptaquin treatment is neuroprotective, but the potential mechanisms need further investigation. Read the Editorial Highlight for this article on page 645.

The Long-Term Impairment in Redox Homeostasis Observed in the Hippocampus of Rats Subjected to Global Perinatal Asphyxia (PA) Implies Changes in Glutathione-Dependent Antioxidant Enzymes and TIGAR-Dependent Shift Towards the Pentose Phosphate Pathways: Effect of Nicotinamide

We have recently reported that global perinatal asphyxia (PA) induces a regionally sustained increase in oxidized glutathione (GSSG) levels and GSSG/GSH ratio, a decrease in tissue-reducing capacity, a decrease in catalase activity, and an increase in apoptotic caspase-3-dependent cell death in rat neonatal brain up to 14 postnatal days, indicating a long-term impairment in redox homeostasis. In the present study, we evaluated whether the increase in GSSG/GSH ratio observed in hippocampus involves changes in glutathione reductase (GR) and glutathione peroxidase (GPx) activity, the enzymes reducing glutathione disulfide (GSSG) and hydroperoxides, respectively, as well as catalase, the enzyme protecting against peroxidation. The study also evaluated whether there is a shift in the metabolism towards the penthose phosphate pathway (PPP), by measuring TIGAR, the TP53-inducible glycolysis and apoptosis regulator, associated with delayed cell death, further monitoring calpain activity, involved in bax-dependent cell death, and XRCC1, a scaffolding protein interacting with genome sentinel proteins. Global PA was induced by immersing fetus-containing uterine horns removed by a cesarean section from on term rat dams into a water bath at 37 °C for 21 min. Asphyxia-exposed and sibling cesarean-delivered fetuses were manually resuscitated and nurtured by surrogate dams. Animals were euthanized at postnatal (P) days 1 or 14, dissecting samples from hippocampus to be assayed for glutathione, GR, GPx (all by spectrophotometry), catalase (Western blots and ELISA), TIGAR (Western blots), calpain (fluorescence), and XRCC1 (Western blots). One hour after delivery, asphyxia-exposed and control neonates were injected with either 100 μl saline or 0.8 mmol/kg nicotinamide, i.p., shown to protect from the short- and long-term consequences of PA. It was found that global PA produced (i) a sustained increase of GSSG levels and GSSG/GSH ratio at P1 and P14; (ii) a decrease of GR, GPx, and catalase activity at P1 and P14; (iii) a decrease at P1, followed by an increase at P14 of TIGAR levels; (iv) an increase of calpain activity at P14; and (v) an increase of XRCC1 levels, but only at P1. (vi) Nicotinamide prevented the effect of PA on GSSG levels and GSSG/GSH ratio, and on GR, GPx, and catalase activity, also on increased TIGAR levels and calpain activity observed at P14. The present study demonstrates that the long-term impaired redox homeostasis observed in the hippocampus of rats subjected to global PA implies changes in GR, GPx, and catalase, and a shift towards PPP, as indicated by an increase of TIGAR levels at P14.