Umbilical cord blood therapy modulates neonatal hypoxic ischemic brain injury in both females and males.

Preclinical and clinical studies have shown that sex is a significant risk factor for perinatal morbidity and mortality, with males being more susceptible to neonatal hypoxic ischemic (HI) brain injury. No study has investigated sexual dimorphism in the efficacy of umbilical cord blood (UCB) cell therapy. HI injury was induced in postnatal day 10 (PND10) rat pups using the Rice-Vannucci method of carotid artery ligation. Pups received 3 doses of UCB cells (PND11, 13, 20) and underwent behavioural testing. On PND50, brains were collected for immunohistochemical analysis. Behavioural and neuropathological outcomes were assessed for sex differences. HI brain injury resulted in a significant decrease in brain weight and increase in tissue loss in females and males. Females and males also exhibited significant cell death, region-specific neuron loss and long-term behavioural deficits. Females had significantly smaller brains overall compared to males and males had significantly reduced neuron numbers in the cortex compared to females. UCB administration improved multiple aspects of neuropathology and functional outcomes in males and females. Females and males both exhibited injury following HI. This is the first preclinical evidence that UCB is an appropriate treatment for neonatal brain injury in both female and male neonates.

Sex differences in Hippocampal Memory and Learning following Neonatal Brain Injury: Is There a Role for Estrogen Receptor-α?

Neonatal encephalopathy due to hypoxia-ischemia (HI) leads to severe, life-long morbidities in thousands of neonates born in the USA and worldwide each year. Varying capacities of long-term episodic memory, verbal working memory, and learning can present without cerebral palsy and have been associated with the severity of neonatal encephalopathy sustained at birth. Among children who sustain a moderate degree of HI at birth, girls have larger hippocampal volumes compared to boys. Clinical studies indicate that female neonatal brains are more resistant to the effects of neonatal HI, resulting in better long-term cognitive outcomes compared to males with comparable brain injury. Our most recent mechanistic studies have addressed the origins and cellular basis of sex differences in hippocampal neuroprotection following neonatal HI-related brain injury and implicate estrogen receptor-α (ERα) in the neurotrophin receptor-mediated hippocampal neuroprotection in female mice. This review summarizes the recent findings on ERα-dependent, neurotrophin-mediated hippocampal neuroprotection and weighs the evidence that this mechanism plays an important role in preservation of long-term memory and learning following HI in females.

FGF21 promotes functional recovery after hypoxic-ischemic brain injury in neonatal rats by activating the PI3K/Akt signaling pathway via FGFR1/ß-klotho.

Perinatal asphyxia often results in neonatal cerebral hypoxia-ischemia (HI), which is associated with high mortality and severe long-term neurological deficits in newborns. Currently, there are no effective drugs to mitigate the functional impairments post-HI. Previous studies have shown that fibroblast growth factor 21 (FGF21) has a potential neuroprotective effect against brain injury. However, the effect of FGF21 on neonatal HI brain injury is unclear. In the present study, both in vivo and in vitro models were used to assess whether recombinant human FGF21 (rhFGF21) could exert a neuroprotective effect after HI and explore the associated mechanism. The results showed that the rhFGF21 treatment remarkably reduced the infarct volume, ameliorated the body weight and improved the tissue structure after HI in neonatal rats. In addition, the rhFGF21 treatment lengthened the running endurance times in the rotarod test and decreased the mean escape latencies and increased the number of platform crossings in the Morris water maze test at 21 d post-HI insult. In contrast, the FGFR1 inhibitor PD173074 and PI3K inhibitor LY294002 partially reversed these therapeutic effects. In isolated primary cortical neurons, the rhFGF21 treatment protected primary neurons from oxygen-glucose deprivation (OGD) insult by inhibiting neuronal apoptosis and promoting neuronal survival. Both our in vivo and in vitro results reveal that rhFGF21 could inhibit neuronal apoptosis by activating the PI3K/Akt signaling pathway via FGF21/FGFR1/ß-klotho complex formation. Therefore, rhFGF21 may be a promising therapeutic agent for promoting functional recovery after HI-induced neonatal brain injury.

Ginkgolide B ameliorates NLRP3 inflammasome activation after hypoxic-ischemic brain injury in the neonatal male rat.

INTRODUCTION: Perinatal hypoxic-ischemic (HI) insult is an important cause of brain injury in neonates. The development of novel treatment strategies for neonates with HI brain injury is urgently needed. Ginkgolide B (GB) is a main component of Ginkgo biloba extracts with a long history of use in traditional Chinese medicine. However, it is unknown whether GB could play a protective role in hypoxic stress in immature animals. METHODS: Using neonatal hypoxic-ischemic (HI) brain injury model of rat pups, neurological score, infarct size, and brain edema were evaluated after HI injury. The activation of microglia and the production of IL-1ß and IL-18 were detected by immunohistochemistry and ELISA, respectively. A priming signal (NF-κB P65) and an activation signal (Caspase-1) of NLRP3 inflammasome activation were detected by western blot analyses. RESULTS: GB administrated 30 min prior to ischemia induction can improve neurological disorder, reduce infarct volume and alleviate cerebral edema. Compared with the HI groups, GB inhibited the activation of microglia and decreased the production of IL-1ß and IL-18 in neocortex. Furthermore, GB reduced NLRP3 expression mainly in microglia, and significantly inhibited the expression of Caspase-1 and the nuclear translocation of NF-κB P65, preventing NLRP3 inflammasome activation. CONCLUSIONS: GB ameliorates hypoxic-ischemic brain injury in the neonatal male rat via inhibiting NLRP3 inflammasome activation.

The paracrine effect of cobalt chloride on BMSCs during cognitive function rescue in the HIBD rat.

Hypoxia-ischemia (HI)-induced perinatal encephalopathy frequently causes chronic neurological morbidities and acute mortality. Bone mesenchymal stem cell (BMSC) transplantation could potentially promote functional and anatomical recovery of ischemic tissue. In vitro hypoxic preconditioning is an effective strategy to improve the survival of BMSCs in ischemic tissue. In this study, cobalt chloride (CoCl2) preconditioned medium from BMSC cultures was injected into the left lateral ventricle of HI rats using a micro-osmotic pump at a flow rate 1.0µl/h for 7 days. The protein levels of HIF-1α and its target genes, vascular endothelial growth factor and erythropoietin, markedly increased after CoCl2 preconditioning in BMSCs. In 7-week-old rats that received CoCl2 preconditioned BMSC medium, results of the Morris water maze test indicated ameliorated spatial working memory function following hypoxia-ischemia damage. Neuronal loss, cellular disorganization, and shrinkage in brain tissue were also ameliorated. Extracellular field excitatory postsynaptic potentials (fEPSPs) in the brain slices of 8-week-old rats were recorded; administration of CoCl2 preconditioned BMSC culture medium induced a progressive increment of baseline and amplitude of the fEPSPs. Immunohistochemical quantification showed that GluR2 protein expression increased. In conclusion, CoCl2 activates HIF-1α signals in BMSCs. CoCl2 preconditioned BMSC culture medium likely effects neuroprotection by inducing long-term potentiation (LTP), which could be associated with GluR2 expression. The paracrine effects of hypoxia preconditioning on BMSCs could have applications in novel cell-based therapeutic strategies for hypoxic and ischemic brain injury.

Vitamin D improves functional outcomes in neonatal hypoxic ischemic male rats treated with N-acetylcysteine and hypothermia.

Hypothermia treatment neuroprotects approximately 50% of neonates who present with moderate to severe hypoxic ischemic encephalopathy (HIE). N-acetylcysteine (NAC), a potent antioxidant, is neuroprotective in combination with hypothermia in neonatal hypoxia-ischemia (HI) female rats, but less protective in males. Vitamin D is a neurosteroid, which may provide immunomodulation and improve outcomes for both sexes. We investigated the efficacy of this combination of drugs with hypothermia after severe HI, as well as potential mechanisms of vitamin D effects in the transition to chronic inflammation. DOL 7 rats were randomized to sham, or HI and hypothermia treated with either saline (HYPO), NAC (50 mg/kg/d, HNAC), or HNAC plus 1,25-dihydroxy-vitamin D3 (0.1 µg/kg/d, HNAC + VitD) daily for 2 weeks. A second set of animals were randomized and treated for 11 days to investigate vitamin D metabolism and inflammatory mediators. Rats treated with HNAC + VitD performed significantly better on tests of strength and use of affected limb, adaptive sensorimotor skills, motor sequence learning, and working memory than either HYPO or HNAC, particularly benefiting male rats. Significantly fewer rats in the HNAC + VitD group had severe hemispheric volume loss. HI injury decreased serum vitamin D at 11 days and induced the enzyme that deactivates vitamin D in the hippocampus, particularly in males. Persistent vitamin D dysregulation was seen in both hippocampi in males, which was not reversed by hypothermia. Vitamin D in combination with hypothermia and NAC supports functional recovery in both sexes of neonatal rats significantly better than hypothermia alone or hypothermia and NAC in this severe HI model.

Association of Catastrophic Neonatal Outcomes With Increased Rate of Subsequent Cesarean Deliveries.

OBJECTIVE: To evaluate whether full-term deliveries resulting in neonates diagnosed with hypoxic-ischemic encephalopathy are associated with a significant increase in the rate of subsequent unscheduled cesarean deliveries. METHODS: We conducted a retrospective chart review study and examined all deliveries in the Department of Obstetrics and Gynecology at Hadassah University Hospital, Mt. Scopus campus, Jerusalem, Israel, during 2009-2014. We reviewed all cases of hypoxic-ischemic encephalopathy in singleton, term, liveborn neonates and identified seven such cases, three of which were attributed to obstetric mismanagement and four that were not. We measured the rate of unscheduled cesarean deliveries before and after the events and their respective hazard ratio. RESULTS: Before a mismanaged delivery resulting in hypoxic-ischemic encephalopathy, the baseline rate of unscheduled cesarean deliveries was approximately 80 unscheduled cesarean deliveries for every 1,000 deliveries. In the first 4 weeks immediately after each of the three identified cases, there was a significant increase in the rate of unscheduled cesarean deliveries by an additional 48 unscheduled cesarean deliveries per 1,000 deliveries (95% confidence interval [CI] 27-70/1,000). This increase was transient and lasted approximately 4 weeks. We estimated that each case was associated with approximately 17 additional unscheduled cesarean deliveries (95% CI 8-27). There was no increase in the rate of unscheduled cesarean deliveries in cases of hypoxic-ischemic encephalopathy that were not associated with mismanagement. CONCLUSION: The increase in the rate of unscheduled cesarean deliveries after a catastrophic neonatal outcome may result in short-term changes in obstetricians' risk evaluation.

Overexpression of HIF-1α in mesenchymal stem cells contributes to repairing hypoxic-ischemic brain damage in rats.

Preclinical researches on mesenchymal stem cells (MSCs) transplantation, which is used to treat hypoxic-ischemic (HI) brain damage, have received inspiring achievements. However, the insufficient migration of active cells to damaged tissues has limited their potential therapeutic effects. There are some evidences that hypoxia inducible factor-1 alpha (HIF-1α) promotes the viability and migration of the cells. Here, we aim to investigate whether overexpression of HIF-1α in MSCs could improve the viability and migration capacity of cells, and its therapeutic efficiency on HI brain damage. In the study, MSCs with HIF-1α overexpression was achieved by recombinant lentiviral vector and transplanted to the rats subsequent to HI. Our data indicated that overexpression of HIF-1α promoted the viability and migration of MSCs, HIF-1α overexpressed MSCs also had a stronger therapeutic efficiency on HI brain damaged treatment by mitigating the injury on behavioral and histological changes evoked by HI insults, accompanied with more MSCs migrating to cerebral damaged area. This study demonstrated that HIF-1α overexpression could increase the MSCs' therapeutic efficiency in HI and the promotion of the cells' directional migration to cerebral HI area by overexpression may be responsible for it, which showed that transplantation of MSCs with HIF-1α overexpression is an attractive therapeutic option to treat HI-induced brain injury in the future.

Neurodevelopmental outcome in hypoplastic left heart syndrome: Impact of perioperative cerebral tissue oxygenation of the Norwood procedure.

OBJECTIVES: Patients with hypoplastic left heart syndrome are at risk for neurodevelopmental impairment. Hypoxic-ischemic brain injury during neonatal treatment might be a relevant cause. We evaluated the association between cerebral oxygenation in the perioperative course of the Norwood procedure and neurodevelopmental outcome. METHODS: Cerebral tissue oxygen saturation (ScO2) was obtained by near-infrared spectroscopy for 24 hours before and 48 hours after surgery in 43 patients. Full-scale, verbal, and performance IQ scores were evaluated with the Wechsler Preschool and Primary Scale of Intelligence at a median of 4.5 years (range, 3.5-6.8 years). Cognitive functions were assessed with the German Kognitiver Entwicklungstest für das Kindergartenalter (KET-KID). RESULTS: Mean IQ scores and KET-KID percentile ranks were in the lower-normal range (full-scale IQ, 94 ± 11; verbal IQ, 97 ± 13; performance IQ, 93 ± 9; KET-KID global, 42 ± 27; verbal, 48 ± 29; nonverbal, 37 ± 23). Scores were below average (full scale IQ <85 or KET-KID <16th percentile) in 12 cases. Mean preoperative ScO2 was lower in patients scoring below average (56.8% ± 7.1% vs 61.7% ± 5.8%; P = .028) and was correlated with full-scale IQ (r = 0.495; P = .001), verbal IQ (r = 0.524; P = .001), and performance IQ (r = 0.386; P = .012) scores, and with global (r = 0.360; P = .018) and verbal (r = 0.395, P = .009) KET-KID scores. A relationship between IQ or KET-KID scores and postoperative ScO2 was not found. Gestational age, head circumference z-score, age at surgery, and postoperative length of stay were associated with IQ and KET-KID scores. CONCLUSIONS: Neurodevelopmental outcome was in the lower-normal range. Along with innate patient factors, preoperative cerebral tissue oxygenation is likely an important determinant of cognitive development.

Endogenous IL-6 of mesenchymal stem cell improves behavioral outcome of hypoxic-ischemic brain damage neonatal rats by supressing apoptosis in astrocyte.

Mesenchymal stem cell (MSC) transplantation reduces the neurological impairment caused by hypoxic-ischemic brain damage (HIBD) via immunomodulation. In the current study, we found that MSC transplantation improved learning and memory function and enhanced long-term potentiation in neonatal rats subjected to HIBD and the amount of IL-6 released from MSCs was far greater than that of other cytokines. However, the neuroprotective effect of MSCs infected with siIL-6-transduced recombinant lentivirus (siIL-6 MSCs) was significantly weakened in the behavioural tests and electrophysiological analysis. Meanwhile, the hippocampal IL-6 levels were decreased following siIL-6 MSC transplantation. In vitro, the levels of IL-6 release and the levels of IL-6R and STAT3 expression were increased in both primary neurons and astrocytes subjected to oxygen and glucose deprivation (OGD) following MSCs co-culture. The anti-apoptotic protein Bcl-2 was upregulated and the pro-apoptotic protein Bax was downregulated in OGD-injured astrocytes co-cultured with MSCs. However, the siIL-6 MSCs suppressed ratio of Bcl-2/Bax in the injured astrocytes and induced apoptosis number of the injured astrocytes. Taken together, these data suggest that the neuroprotective effect of MSC transplantation in neonatal HIBD rats is partly mediated by IL-6 to enhance anti-apoptosis of injured astrocytes via the IL-6/STAT3 signaling pathway.

Sevoflurane postconditioning improves long-term learning and memory of neonatal hypoxia-ischemia brain damage rats via the PI3K/Akt-mPTP pathway.

BACKGROUND: Volatile anesthetic postconditioning has been documented to provide neuroprotection in adult animals. Our aim was to investigate whether sevoflurane postconditioning improves long-term learning and memory of neonatal hypoxia-ischemia brain damage (HIBD) rats, and whether the PI3K/Akt pathway and mitochondrial permeability transition pore (mPTP) opening participate in the effect. METHODS: Seven-day-old Sprague-Dawley rats were subjected to brain HI and randomly allocated to 10 groups (n=24 each group) and treated as follows: (1) Sham, without hypoxia-ischemia; (2) HI/Control, received cerebral hypoxia-ischemia; (3) HI+Atractyloside (Atr), (4) HI+Cyclosporin A (CsA), (5) HI+sevoflurane (Sev), (6) HI+Sev+ LY294002 (LY), (7) HI+Sev+ L-NAME (L-N), (8) HI+Sev+ SB216763 (SB), (9) HI+Sev+Atr, and (10) HI+Sev+CsA. Twelve rats in each group underwent behavioral testing and their brains were harvested for hippocampus neuron count and morphology study. Brains of the other 12 animals were harvested 24h after intervention to examine the expression of Akt, p-Akt, eNOS, p-eNOS, GSK-3ß, p-GSK-3ß by Western bolting and mPTP opening. RESULTS: Sevoflurane postconditioning significantly improved the long-term cognitive performance of the rats, increased the number of surviving neurons in CA1 and CA3 hippocampal regions, and protected the histomorphology of the left hippocampus. These effects were abolished by inhibitors of PI3K/eNOS/GSK-3ß. Although blocking mPTP opening simulated sevoflurane postconditioning-induced neuroprotection, it failed to enhance it. CONCLUSIONS: Sevoflurane postconditioning exerts a neuroprotective effect against HIBD in neonatal rats via PI3K/Akt/eNOS and PI3K/Akt/GSK-3ß pathways, and blockage of mPTP opening may be involved in attenuation of histomorphological injury.

Sex differences in cell genesis, hippocampal volume and behavioral outcomes in a rat model of neonatal HI.

Hypoxia-ischemia (HI) of the brain in near-term and term infants is a leading cause of infant mortality and lifelong disability but current therapeutic approaches remain limited. Males consistently display greater vulnerability to the deleterious consequences of HI in both humans and animal models. Neurogenesis increases after neonatal HI and offers a potential therapeutic target for recovery. The steroid hormone estradiol has been extensively explored as a neuroprotectant in adult models of stroke but with mixed results. Less consideration has been afforded to this naturally occurring agent in the developing brain, which has unique challenges from the adult. Using a model of term HI in the rat we have explored the impact of this insult on cell genesis in the hippocampus of males and females and the ability of estradiol treatment immediately after insult to restore function. Both short-term (3 days) and long-term (7 days) post-injury were assessed and revealed that only females had markedly increased cell genesis on the short-term but both sexes were increased long-term. A battery of behavioral tests revealed motor impairment in males and compromised episodic memory while both sexes were modestly impaired in spatial memory. Juvenile social play was also depressed in both sexes after HI. Estradiol therapy improved behavioral performance in both sexes but did not reverse a deficit in hippocampal volume ipsilateral to the insult. Thus the effects of estradiol do not appear to be via cell death or proliferation but rather involve other components of neural functioning.

Resveratrol Reverses the Synaptic Plasticity Deficits in a Chronic Cerebral Hypoperfusion Rat Model.

BACKGROUND: Dementia is the most prevalent neurological disease in aged people. Chronic cerebral hypoperfusion (CCH) is one of the causes of vascular dementia (VaD) and is also an etiological factor for Alzheimer's disease (AD). However, effective therapy for those two diseases is still missing. Resveratrol is a polyphenol produced by plants that have multiple biological functions, such as increased life span and delay in the onset of diseases associated with aging. It is known supplement with resveratrol could exert neuroprotection against multiple injury factors induced neuronal death and degeneration, as well as the cognitive decline of CCH rat model. METHODS: The morris water maze was used to evaluate the learning and memory, electrophysiological recording was used to detect the synaptic plasticity, the Golgi staining was used to examine the change of dendritic spines, the western blot was used to detect the proteins levels. RESULTS: We reported that resveratrol pretreatment effectively restore the synaptic plasticity in CCH rats both functional and structural. We also found that the PKA-CREB activation may be a major player in resveratrol-mediated neuroprotection in CCH model. CONCLUSIONS: Our data provide the mechanistic evidence for the neuroprotective effects of resveratrol in vascular dementia.

Pretreatment with Resveratrol Prevents Neuronal Injury and Cognitive Deficits Induced by Perinatal Hypoxia-Ischemia in Rats.

Despite advances in neonatal care, hypoxic-ischemic brain injury is still a serious clinical problem, which is responsible for many cases of perinatal mortality, cerebral palsy, motor impairment and cognitive deficits. Resveratrol, a natural polyphenol with important anti-oxidant and anti-inflammatory properties, is present in grapevines, peanuts and pomegranates. The aim of the present work was to evaluate the possible neuroprotective effect of resveratrol when administered before or immediately after a hypoxic-ischemic brain event in neonatal rats by analyzing brain damage, the mitochondrial status and long-term cognitive impairment. Our results indicate that pretreatment with resveratrol protects against brain damage, reducing infarct volume, preserving myelination and minimizing the astroglial reactive response. Moreover its neuroprotective effect was found to be long lasting, as behavioral outcomes were significantly improved at adulthood. We speculate that one of the mechanisms for this neuroprotection may be related to the maintenance of the mitochondrial inner membrane integrity and potential, and to the reduction of reactive oxygen species. Curiously, none of these protective features was observed when resveratrol was administered immediately after hypoxia-ischemia.

Assessment of long-term safety and efficacy of intranasal mesenchymal stem cell treatment for neonatal brain injury in the mouse.

BACKGROUND: For clinical translation, we assessed whether intranasal mesenchymal stem cell (MSC) treatment after hypoxia-ischemia (HI) induces neoplasia in the brain or periphery at 14 mo. Furthermore, the long-term effects of MSCs on behavior and lesion size were determined. METHOD: HI was induced in 9-d-old mice. Pups received an intranasal administration of 0.5 × 10(6) MSCs or vehicle at 10 d post-HI. Full macroscopical and microscopical pathological analysis of 39 organs per mouse was performed. Sensorimotor behavior was assessed in the cylinder-rearing test at 10 d, 28 d, 6 mo, and 9 mo. Cognition was measured with the novel object recognition test at 3 and 14 mo post-HI. Lesion size was determined by analyzing mouse-anti-microtubule-associated protein 2 (MAP2) and mouse-anti-myelin basic protein (MBP) staining at 5 wk and 14 mo. RESULTS: At 14 mo post-HI, we did not observe any neoplasia in the nasal turbinates, brain, or other organs of HI mice treated with MSCs. Furthermore, our results show that MSC-induced improvement of sensorimotor and cognitive function is long lasting. In contrast, HI-vehicle mice showed severe behavioral impairment. Recovery of MAP2- and MBP-positive area lasted up to 14 mo following MSC treatment. CONCLUSION: Our results provide strong evidence of the long-term safety and positive effects of MSC treatment following neonatal HI in mice.

Intraventricular injection of human dental pulp stem cells improves hypoxic-ischemic brain damage in neonatal rats.

OBJECTIVE: To investigate the effect of intraventricular injection of human dental pulp stem cells (DPSCs) on hypoxic-ischemic brain damage (HIBD) in neonatal rats. METHODS: Thirty-six neonatal rats (postnatal day 7) were assigned to control, HIBD, or HIBD+DPSC groups (n = 12 each group). For induction of HIBD, rats underwent left carotid artery ligation and were exposed to 8% to 10% oxygen for 2 h. Hoechst 33324-labeled human DPSCs were injected into the left lateral ventricle 3 days after HIBD. Behavioral assays were performed to assess hypoxic-ischemic encephalopathy (HIE), and on postnatal day 45, DPSC survival was assessed and expression of neural and glial markers was evaluated by immunohistochemistry and Western blot. RESULTS: The HIBD group showed significant deficiencies compared to control on T-maze, radial water maze, and postural reflex tests, and the HIBD+DPSC group showed significant improvement on all behavioral tests. On postnatal day 45, Hoechst 33324-labeled DPSC nuclei were visible in the injected region and left cortex. Subsets of DPSCs showed immunostaining for neuronal (neuron-specific enolase [NSE], Nestin) and glial markers (glial fibrillary acidic protein [GFAP], O4). Significantly decreased staining/expression for NSE, GFAP, and O4 was found in the HBID group compared to control, and this was significantly increased in the HBID+DPSC group. CONCLUSION: Intraventricular injection of human DPSCs improves HIBD in neonatal rats.

Are the consequences of neonatal hypoxia-ischemia dependent on animals' sex and brain lateralization?

Hypoxia-ischemia on 3-day-old rats (HIP3) allows the investigation of HI damage in the immature brain. HIP3 is characterized for neurological disabilities caused by white matter injury. This study investigates the relationship between animals' sex and injured hemisphere on HIP3 consequences. Male and female Wistar rats had their right or left common carotid artery occluded under halotane anesthesia and exposed to 8% O2 for 1.5 h. Control rats received sham surgery and exposure to 1.5 h of room air in isolation of their mothers. Sex and injured hemisphere influence in Na+/K+ -ATPase activity 24h after lesion: females and the right brain hemispheres showed decreased enzymatic activity after HIP3. Cognitive impairment was observed in step-down inhibitory avoidance, in which females HIP3 left injured were the most damaged. Histological analysis showed a trend to white matter damage in females left injured without hemispherical nor hippocampal volume decrease in HIP3 rats at postnatal day 21. However, at PND90, hemisphere and sex effects were noted in hemispherical volume and myelination: left brain hemisphere and the females evidenced higher histological damage. Our results points to an increased resistance of male rats and right brain hemisphere to support the impairment caused in Na+/K+ -ATPase activity early after HIP3, and evidencing more discrete behavioral impairments and histological damage at adulthood. Present data adds new evidence of distinct effects of brain lateralization and sex vulnerability on biochemical, behavioral and histological parameters after hypoxia-ischemia.

Perioperative cerebral oxygen saturation in neonates with hypoplastic left heart syndrome and childhood neurodevelopmental outcome.

OBJECTIVES: Neonates with hypoplastic left heart syndrome have significant hemodynamic threats to cerebral perfusion and are at risk of reduced neurodevelopmental performance. We hypothesized that cerebral hypoxia, detectable by near-infrared spectroscopy in the early postoperative period, would be related to later neurodevelopmental performance. METHODS: The study population was a sequential cohort of patients who had undergone stage 1 palliation of hypoplastic left heart syndrome under standard conditions, including neonatal perioperative monitoring with cerebral near-infrared spectroscopy, and who had undergone a neurodevelopmental assessment at age 4 to 5 years. The neonatal demographic and 48-hour perioperative hemodynamic parameters, including cerebral oxygen saturation, were tested for their relationship to 4 domains of neurodevelopmental performance, including visual-motor integration in childhood in univariate and multivariate models. The neurodevelopmental scores were classified as low if less than 85 (-1 standard deviation) and abnormal if less than 70 (-2 standard deviations). RESULTS: For the 51 patients in the surgical cohort, the early survival was 94%, the cumulative survival was 86%, and the neurodevelopmental assessment was completed by 21 (48%) of the survivors, without evidence of an ascertainment bias. At the test age of 56.3 ± 5.5 months, the composite neurodevelopmental index, constructed from equally weighted measures in 4 domains, was 97.6 ± 9.6, not different from the age-based norms, with 3 of 21 in the low range and none abnormal. The mean visual-motor integration was 93.4 ± 14, slightly less than the population norm (P < .05), with 2 of 21 having low scores and 1 abnormal scores. In patients with low to abnormal visual-motor integration, the perioperative stage 1 palliation cerebral oxygenation saturation was significantly lower (63.6 ± 8.1 vs 67.8 ± 8.1, P < .05). Two patients had discrete embolic strokes after their initial hospitalization; the occurrence of late stroke reduced the visual-motor integration performance but was not related to the early cerebral oxygen saturation. Nonlinear relationships of cerebral oxygen saturation to the neurodevelopmental measures found cerebral oxygen saturation thresholds of 49% to 62%. The hours at a cerebral oxygen saturation less than 45% and 55% were related to low visual-motor integration and neurodevelopmental index scores in the univariate and multivariate models. A multivariate model of age and weight at stage 1 palliation, cerebral oxygen saturation, arterial oxygen saturation, cardiopulmonary bypass and deep hypothermic circulatory arrest times, and later stroke predicted visual-motor integration to an important degree (R(2) = 0.53, P < .001). The actual and predicted visual-motor integration and neurodevelopmental index were normal when a cerebral oxygen saturation less than 45% and other risk conditions were avoided. CONCLUSIONS: Neurodevelopmental performance was related to demographic, neonatal perioperative physiologic, and later factors. Perioperative cerebral oxygenation assessed by near-infrared spectroscopy can detect hypoxic-ischemic conditions associated with injury and reduced neurodevelopmental performance and was the most significant physiologic factor identified. These data suggest that efforts to avoid cerebral hypoxia are likely to improve the outcomes in this high-risk population.

Sodium pyruvate reduces hypoxic-ischemic injury to neonatal rat brain.

BACKGROUND: Neonatal hypoxia-ischemia (HI) remains a major cause of severe brain damage and is often associated with high mortality and lifelong disability. Immature brains are extremely sensitive to HI, shown as prolonged mitochondrial neuronal death. Sodium pyruvate (SP), a substrate of the tricarboxylic acid cycle and an extracellular antioxidant, has been considered as a potential treatment for hypoxic-ischemic encephalopathy, but its effects have not been evaluated in appropriate animal models for hypoxic-ischemic encephalopathy. METHODS: This investigation used primary cortical neuron cultures derived from neonatal rats subjected to oxygen and glucose deprivation (OGD) and a well-established neonatal rat HI model. RESULTS: HI caused brain tissue loss and impaired sensorimotor function and spatial memory whereas SP significantly reduced brain damage and improved neurological performance. These neuroprotective effects of SP are likely the result of improved cerebral metabolism as demonstrated by maintaining adenosine triphosphate (ATP) levels and preventing an increase in intracellular reactive oxygen species (ROS) levels. SP treatment also decreased levels of Bax, a death signal for immature neurons, blocked caspase-3 activation, and activated a key survival signaling kinase, Akt, both in vitro and in vivo. CONCLUSION: SP protected neonatal brain from hypoxic-ischemic injury through maintaining cerebral metabolism and mitochondrial function.

Long-term neuroprotective effects of allopurinol after moderate perinatal asphyxia: follow-up of two randomised controlled trials.

OBJECTIVE: Free-radical-induced reperfusion injury has been recognised as an important cause of brain tissue damage after birth asphyxia. Allopurinol reduces the formation of free radicals, thereby potentially limiting the amount of hypoxia-reperfusion damage. In this study the long-term outcome of neonatal allopurinol treatment after birth asphyxia was examined. DESIGN: Follow-up of 4 to 8 years of two earlier performed randomised controlled trials. SETTING: Leiden University Medical Center, University Medical Center Groningen and University Medical Center Utrecht, The Netherlands. PATIENTS: Fifty-four term infants were included when suffering from moderate-to-severe birth asphyxia in two previously performed trials. INTERVENTION: Infants either received 40 mg/kg allopurinol (with an interval of 12 h) starting within 4 h after birth or served as controls. MAIN OUTCOME MEASURES: Children, who survived, were assessed with the Wechsler Preschool and Primary Scales of Intelligence test or Wechsler Intelligence Scale for Children and underwent a neurological examination. The effect of allopurinol on severe adverse outcome (defined as mortality or severe disability at the age of 4-8 years) was examined in the total group of asphyxiated infants and in a predefined subgroup of moderately asphyxiated infants (based on the amplitude integrated electroencephalogram). RESULTS: The mean age during follow-up (n=23) was 5 years and 5 months (SD 1 year and 2 months). There were no differences in long-term outcome between the allopurinol-treated infants and controls. However, subgroup analysis of the moderately asphyxiated group showed significantly less severe adverse outcome in the allopurinol-treated infants compared with controls (25% vs 65%; RR 0.40, 95%CI 0.17 to 0.94). CONCLUSIONS: The reported data may suggest a (neuro)protective effect of neonatal allopurinol treatment in moderately asphyxiated infants.