Neuroprotective agents for neonatal hypoxic-ischemic brain injury

Neuroinflammation mediates the progression of neonate hypoxia-ischemia brain damage to Alzheimer's disease: a bioinformatics and experimental study

Background

Traumatic brain injury (TBI) can generally be divided into focal damage and diffuse damage, and neonate Hypoxia-Ischemia Brain Damage (nHIBD) is one of the causes of diffuse damage. Patients with nHIBD are at an increased risk of developing Alzheimer's disease (AD). However, the shared pathogenesis of patients affected with both neurological disorders has not been fully elucidated.

Purpose

We here aim to identify the shared molecular signatures between nHIBD and AD. We used an integrated analysis of the cortex gene expression data, targeting differential expression of genes related to the mechanisms of neurodegeneration and cognitive impairment following traumatic brain injury.

Methods

The gene expression profiles of Alzheimer's disease (GSE203206) and that of Neonate Hypoxia-Ischemia Brain Damage (GSE23317) were obtained from the Gene Expression Omnibus (GEO) database. After identifying the common differentially expressed genes (DEGs) of Alzheimer's disease and neonate Hypoxia-Ischemia Brain Damage by limma package analysis, five kinds of analyses were performed on them, namely Gene Ontology (GO) and pathway enrichment analysis, protein-protein interaction network, DEG-transcription factor interactions and DEG-microRNA interactions, protein-drug interactions and protein-disease association analysis, and gene-inflammation association analysis and protein-inflammation association analysis.

Results

In total, 12 common DEGs were identified including HSPB1, VIM, MVD, TUBB4A, AACS, ANXA6, DIRAS2, RPH3A, CEND1, KALM, THOP1, AREL1. We also identified 11 hub proteins, three central regulatory transcription factors, and three microRNAs encoded by the DEGs. Protein-drug interaction analysis showed that CYC1 and UQCRFS1 are associated with different drugs. Gene-disease association analysis shows Mammary Neoplasms, Neoplasm Metastasis, Schizophrenia, and Brain Ischemia diseases are the most relevant to the hub proteins we identified. Gene-inflammation association analysis shows that the hub gene AREL1 is related to inflammatory response, while the protein-inflammation association analysis shows that the hub proteins AKT1 and MAPK14 are related to inflammatory response.

Conclusion

This study provides new insights into the shared molecular mechanisms between AD and nHIBD. These common pathways and hub genes could potentially be used to design therapeutic interventions, reducing the likelihood of Alzheimer's disease development in survivors of neonatal Hypoxic-Ischemia brain injury.

Proinflammatory factors inhibition and fish oil treatment: A promising therapy for neonatal seizures

Brain injury is one of the most important causes of infant mortality and chronic neurological disabilities. Hypoxia is an acute brain injury which led to various cognitive, behavioral, and memory disorders throughout life. Previous studies reported neuroprotective possibilities for fish oil (FO) in brain-injured situations. In this study, we evaluated the effect of the FO diet during the lactation period on seizure activity, behavioral performance, histomorphometry, and inflammatory changes in the brains of hypoxia rats. Male Wistar rats were randomly divided in to 4 groups: Sham (intact rats), hypoxia, FO and FO+hypoxia groups. Hypoxia was induced by keeping neonate rats at PND12 in a hypoxic chamber (7 % oxygen and 93 % nitrogen intensity) for 15 minutes. In the FO groups, rats received oral FO (1 ml/day) for 12 days during the lactation period. Seizure activity was assessed by measuring the number of tonic-clonic seizures and seizure thresholds. Novel object recognition tests (NORT), rotarod, and open field tests were used to measure behavioral performances. A Histological study was performed to evaluate histomorphometric changes in the hippocampus and cerebellum. The gene expression of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) was measured using RT-PCR. Findings showed that the number of tonic-clonic seizures, atrophy, and cell death in the hippocampus and cerebellum, the gene expression of TNF-α and IL-1β in the hippocampus, and behavioral disorders were significantly increased in the hypoxia rats compared to the sham group. Administration of FO in the hypoxia groups significantly decreased the gene expression of TNF-α and IL-1β, the number of tonic-clonic seizures, and neuronal cell death in the hippocampus and cerebellum compared to the hypoxia groups. Furthermore, it can improve behavioral tasks and cognitions.

Melatonin-mediated IGF-1/GLP-1 activation in experimental OCD rats: Evidence from CSF, blood plasma, brain and in-silico investigations

Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by intrusive, repetitive thoughts and behaviors. Our study uses a validated 8-OH-DPAT-induced experimental model of OCD in rodents. We focus on the modulatory effects of Insulin-like growth factor-1 (IGF-1) and glucagon-like peptide-1 (GLP-1), which are linked to neurodevelopment and survival. Current research investigates melatonin, a molecule with neuroprotective properties and multiple functions. Melatonin has beneficial effects on various illnesses, including Alzheimer's, Parkinson's, and depression, indicating its potential efficacy in treating OCD. In the present study, we employed two doses of melatonin, 5 mg/kg and 10 mg/kg, demonstrating a dose-dependent effect on 8-OH-DPAT-induced rat changes. In addition, the melatonin antagonist luzindole 5 mg/kg was utilized to compare and validate the efficacy of melatonin. In-silico studies alsocontribute to understanding the activation of IGF-1/GLP-1 pathways by melatonin. Current research indicates restoring neurochemical measurements on various biological samples (brain homogenates, CSF, and blood plasma) and morphological and histological analyses. In addition, the current research seeks to increase understanding of OCD and investigate potential new treatment strategies. Therefore, it is evident from the aforementioned research that the protective effect of melatonin can serve as a strong basis for developing a new OCD treatment by upregulating IGF-1 and GLP-1 levels. The primary focus of current study revolves around the examination of melatonin as an activator of IGF-1/GLP-1, with the aim of potentially mitigating behavioral, neurochemical, and histopathological abnormalities in an experimental model of obsessive-compulsive disorder caused by 8-OH-DPAT in adult Wistar rats.

Progress in the treatment of neonatal hypoxic-ischemic encephalopathy with umbilical cord blood mononuclear cells

Neonatal hypoxic-ischemic encephalopathy (HIE) is a common disease among newborns, which is a leading cause of neonatal death and permanent neurological sequelae. Therapeutic hypothermia (TH) is the only method for the treatment of HIE that has been recognized effective clinically at home and abroad, but the efficacy is limited. Recent research suggests that the cord blood-derived mononuclear cells (CB-MNCs), which the refer to blood cells containing one nucleus in the cord blood, exert anti-oxidative, anti-inflammatory, anti-apoptotic effects and play a neuroprotective role in HIE. This review focuses on safety and efficacy, the route of administration, dose, timing and combination treatment of CB-MNCs in HIE.

Evaluation of syringin's neuroprotective effect in a model of neonatal hypoxic-ischemic brain injury

BACKGROUND/AIM

A significant cause of mortality and morbidity in the neonatal era is hypoxic-ischemic encephalopathy (HIE). This study examined the histopathological analysis and neuroprotective impact of syringin (SYR) in an experimental HIE rat model.

MATERIAL AND METHODS

On the 7th postnatal day, 24 Wistar albino rats were evaluated in 3 groups using the HIE model under gas anesthesia. In the experiment, Group A received 10 mg/kg SYR plus dimethyl sulfoxide (DMSO), Group B received DMSO only, and Group C served as a sham group. Immunohistochemical techniques were used to assess apoptotic cell measurement and proinflammatory cytokines (TNF-α and IL-1β primary antibodies).

RESULTS

Rats suffering from hypoxic-ischemic brain damage had their apoptosis assessed. The SYR and sham groups had statistically fewer cells undergoing apoptosis (p < 0.001). There was no difference between the groups in terms of IL-1β and TNF-α during immunohistochemical staining. Neuronal degeneration was significantly lower in the histological evaluation of the hippocampus in the SYR group (p = 0.01). A statistically significant difference (p = 0.01) was observed between the SYR and the control groups regarding pericellular and perivascular edema.

CONCLUSION

SYR reduced apoptosis, perivascular and pericellular edema, and neuronal degeneration in rat cerebral tissue. These results raise the possibility that SYR may have a neuroprotective effect on the harm brought on by HIE. This is the first investigation of SYR's function within the HIE paradigm.

PVT1 alleviates hypoxia-induced endothelial apoptosis by enhancing autophagy via the miR-15b-5p/ATG14 and miR-424-5p/ATG14 axis

Endothelial dysfunction plays a crucial role in the pathogenesis of vascular disease. Long noncoding RNA (lncRNA) and microRNA (miRNA) play important roles in various cellular processes and are involved in several vascular endothelial cells (VECs) biological processes, including cell growth, migration, autophagy, and apoptosis. The functions of plasmacytoma variant translocation 1 (PVT1) in VECs have been progressively investigated in recent years, mainly with regard to proliferation and migration of endothelial cells (ECs). However, the mechanism underlying the regulation of autophagy and apoptosis in human umbilical vein endothelial cells (HUVEC) by PVT1 remains unclear. The present study showed that PVT1 knockdown accelerated apoptosis induced by oxygen and glucose deprivation (OGD) through suppression of cellular autophagy. Bioinformatic prediction of PVT1 target miRNAs revealed that PVT1 interacts with miR-15b-5p and miR-424-5p. The study further showed that miR-15b-5p and miR-424-5p inhibit the functions of autophagy related 14 (ATG14) and suppress cellular autophagy. The results showed that PVT1 can function as a competing endogenous RNA (ceRNA) of miR-15b-5p and miR-424-5p and promote cellular autophagy by competitive binding, which down-regulates apoptosis. The results showed that PVT1 can function as a competing endogenous RNA (ceRNA) of miR-15b-5p and miR-424-5p and promote cellular autophagy through competitive binding, which down-regulates apoptosis. The study provides insight into a novel therapeutic target that may be explored in the future for the treatment of cardiovascular disease.

Chloroquine Protects Hypoxia/Ischemia-Induced Neonatal Brain Injury in Rats by Mitigating Blood-Brain Barrier Disruption

Neonatal hypoxic-ischemic (H/I) brain damage (HIBD) is a devastating condition for which there are presently no effective therapeutic strategies against its severe neurological deficits in neonates and young children. Traditionally, H/I induces the compromise of the blood-brain barrier (BBB), which causes neuronal cell death, eventually resulting in brain secondary injury. In addition to neonatal HIBD, chloroquine (CQ) has been proved to exert a protective effect on BBB disruption in several brain injury models. The main purpose of this research was to study whether CQ protects the BBB from H/I insult and confers beneficial neuroprotection in the neonatal Rice-Vannucci rat model. Herein, we reported that CQ administration significantly reduced brain damage and improved behavioral dysplasia after H/I injury. Moreover, we demonstrated the protective effects of CQ on BBB integrity, evidenced by ameliorating brain edema and Evans blue extravasation, inhibiting the degeneration of the tight junction and adherens junction proteins, and improving pericyte survival in neonatal rats after HIBD. These findings indicated that CQ administration protected the BBB against H/I injury, thereby ameliorating brain damage and promoting neurofunctional recovery. Collectively, our data demonstrated that CQ played a crucial role in BBB integrity after neonatal H/I injury, which sheds light on the development of therapeutic agents to treat HIBD.

Melatonin: A Potential Candidate for the Treatment of Experimental and Clinical Perinatal Asphyxia

Perinatal asphyxia is considered to be one of the major causes of brain neurodegeneration in full-term newborns. The worst consequence of perinatal asphyxia is neurodegenerative brain damage, also known as hypoxic-ischemic encephalopathy. Hypoxic-ischemic encephalopathy is the leading cause of mortality in term newborns. To date, due to the complex mechanisms of brain damage, no effective or causal treatment has been developed that would ensure complete neuroprotection. Although hypothermia is the standard of care for hypoxic-ischemic encephalopathy, it does not affect all changes associated with encephalopathy. Therefore, there is a need to develop effective treatment strategies, namely research into new agents and therapies. In recent years, it has been pointed out that natural compounds with neuroprotective properties, such as melatonin, can be used in the treatment of hypoxic-ischemic encephalopathy. This natural substance with anti-inflammatory, antioxidant, anti-apoptotic and neurofunctional properties has been shown to have pleiotropic prophylactic or therapeutic effects, mainly against experimental brain neurodegeneration in hypoxic-ischemic neonates. Melatonin is a natural neuroprotective hormone, which makes it promising for the treatment of neurodegeneration after asphyxia. It is supposed that melatonin alone or in combination with hypothermia may improve neurological outcomes in infants with hypoxic-ischemic encephalopathy. Melatonin has been shown to be effective in the last 20 years of research, mainly in animals with perinatal asphyxia but, so far, no clinical trials have been performed on a sufficient number of newborns. In this review, we summarize the advantages and limitations of melatonin research in the treatment of experimental and clinical perinatal asphyxia.

Effect of Hypoxia-Ischemia on the Expression of Iron-Related Proteins in Neonatal Rat Brains

Hypoxic-ischemic white matter injury (WMI) pathogenesis in preterm infants is not well established, and iron-related proteins in the brain may play an important role in imbalanced iron metabolism. We aimed to investigate the iron-related protein changes in neonatal rats after hypoxia-ischemia (HI), clarify the role of iron-related proteins in hypoxic-ischemic WMI, and potentially provide a new target for the clinical treatment of hypoxic-ischemic WMI in preterm infants. We adopted a WMI animal model of bilateral common carotid artery electrocoagulation combined with hypoxia in neonatal 3-day-old Sprague-Dawley rats. We observed basic myelin protein (MBP) and iron-related protein expression in the brain (ferritin, transferrin receptor [TfR], and membrane iron transporter 1 [FPN1]) via Western blot and double immunofluorescence staining. The expression of MBP in the WMI group was significantly downregulated on postoperative days (PODs) 14, 28, and 56. Ferritin levels were significantly increased on PODs 3, 7, 14, and 28 and were most significant on POD 28, returning to the sham group level on POD 56. FPN1 levels were significantly increased on PODs 7, 28, and 56 and were still higher than those in the sham group on POD 56. TfR expression was significantly upregulated on PODs 1, 7, and 28 and returned to the sham group level on POD 56. Immunofluorescence staining showed that ferritin, TfR, and FPN1 were expressed in neurons, blood vessels, and oligodendrocytes in the cortex and corpus callosum on POD 28. Compared with the sham group, the immune-positive markers of three proteins in the WMI group were significantly increased. The expression of iron-related proteins in the brain (ferritin, FPN1, and TfR) showed spatiotemporal dynamic changes and may play an important role in hypoxic-ischemic WMI.

Bioinformatics-based analysis reveals IDR-1018-mediated ceRNA regulation network for protective effect on hypoxia-ischemic brain injury in neonatal mice

Activation of an innate immune response serves as a key, contributing factor in perinatal brain injury. The current study sought to evaluate the clinical significance of innate defense regulatory peptide 1018 (IDR-1018)-derived peptide mediating ceRNA regulation network as a biomarker in neonatal mice with hypoxic-ischemic brain damage (HIBD). Firstly, bioinformatics analyses were performed to screen the HIBD-related candidate genes, miRNAs, and lncRNAs. The StarBase, miRDB, and LncBase databases were retrieved to obtain the lncRNA-miRNA-mRNA network, which revealed the ceRNA regulatory network mediated by IDR-1018. Subsequently, RT-qPCR was adopted to determine the expression patterns of MIAT, miR-7a-5p, and Plp2 in neonatal mice with HIBD after treatment with IDR-1018. Moreover, the relationship among mRNA, miRNA, and lncRNA in primary hippocampal neurons was verified by means of dual-luciferase reporter assay and RIP assay. Initial findings demonstrated that Plp2, mmu-miR-7a-5p, and three lncRNAs (MIAT, XIST, and 1700020I14RIK) were related to HIBD. Moreover, IDR-1018 could relieve HIBD in neonatal mice. Plp2 and MIAT were down-regulated, while mmu-miR-7a-5p was up-regulated in the striatum, hippocampus, and cortical tissues of the neonatal mice with HIBD, whereas treatment with the IDR-1018 could revere these trends. Additionally, MIAT acted as a ceRNA of miR-7a-5p to elevate Plp2 expression. In conclusion, our findings highlighted that IDR-1018 relieved HIBD in neonatal mice via the MIAT/miR-7a-5p/Plp2 axis.

Early Blood Glucose Level Post-Admission Correlates with the Outcomes and Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy

The antioxidant defense system is involved in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (HIE). To analyze the relationship between first serum blood glucose levels and outcomes in neonatal HIE, seventy-four patients were divided, based on the first glucose level, into group 1 (>0 mg/dL and <60 mg/dL, n =11), group 2 (≥60 mg/dL and <150 mg/dL, n = 49), and group 3 (≥150 mg/dL, n = 14). Abnormal glucose levels had poor outcomes among three groups in terms of the clinical stage (p = 0.001), brain parenchymal lesion (p = 0.004), and neurodevelopmental outcomes (p = 0.029). Hearing impairment was more common in group 3 than in group 1 (p = 0.062) and group 2 (p = 0.010). The MRI findings of group 3 exhibited more thalamus and basal ganglion lesions than those of group 1 (p = 0.012). The glucose level was significantly correlated with clinical staging (p< 0.001), parenchymal brain lesions (p = 0.044), hearing impairment (p = 0.003), and neurodevelopmental outcomes (p = 0.005) by Pearson’s test. The first blood glucose level in neonatal HIE is an important biomarker for clinical staging, MRI findings, as well as hearing and neurodevelopment outcomes. Hyperglycemic patients had a higher odds ratio for thalamus, basal ganglia, and brain stem lesions than hypoglycemic patients with white matter and focal ischemic injury. Hyperglycemia can be due to prolonged or intermittent hypoxia and can be associated with poor outcomes.

Hydrogen Attenuated Inflammation Response and Oxidative in Hypoxic Ischemic Encephalopathy via Nrf2 Mediated the Inhibition of NLRP3 and NF-κB

Hypoxia and ischemia cause neonatal encephalopathy and brain injury and can further result in cerebral palsy, cognitive impairment, growth restriction, and epilepsy. Induction of neuroprotection is a crucial therapeutic strategy for the treatment of perinatal hypoxic-ischaemic encephalopathy (HIE). Hydrogen has neuroprotective effects against brain-related diseases. Inflammation and oxidative stress are the two main pathophysiological mechanisms in neonatal hypoxic-ischaemic injury. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an endogenous redox-sensitive transcription factor that participates in the antioxidant defence system through its effects on inflammation and oxidative stress. Herein, the research focuses on the mechanisms by which Nrf2 participates in the protection of hydrogen against HIE. The model of HIE was established by ligation of the right carotid artery and hypoxia in wild-type (WT) and Nrf2-/- mice. First, Nrf2 pathway activity was detected after hypoxia-ischaemia (HI) followed or not by hydrogen treatment. Brain injury, apoptosis, the inflammatory response, oxidative stress injury, and learning and memory function were assayed. We found that HI induced Nrf2 expression and signalling activation. Hydrogen alleviated the infarction volume, brain water content, neurological scores, apoptosis and long-term learning and memory functions after HI in WT mice but not in Nrf2-/- mice. Moreover, the oxidative products reactive oxygen species (ROS) and malondialdehyde (MDA) and the cytokines tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and High mobility group box 1 (HMGB1) were reduced and the antioxidant enzymes Superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) were upregulated by hydrogen treatment after HI in WT mice, but not in Nrf2-/- mice. In addition, the absence of Nrf2 abolished the suppressive effect of hydrogen on the expression of Nacht, Lrr, and Pyd domains-containing protein 3 (NLRP3) pathway members and p65 NF-κB after HI. Taken together, our findings showed that hydrogen alleviated cellular injury and apoptosis, neurobehavioural deficits, the inflammatory response and oxidative stress via the Nrf2-mediated NLRP3 and NF-κB pathways.

Therapies for neonatal encephalopathy: Targeting the latent, secondary and tertiary phases of evolving brain injury

In term and near-term neonates with neonatal encephalopathy, therapeutic hypothermia protocols are well established. The current focus is on how to improve outcomes further and the challenge is to find safe and complementary therapies that confer additional protection, regeneration or repair in addition to cooling. Following hypoxia-ischemia, brain injury evolves over three main phases (latent, secondary and tertiary), each with a different brain energy, perfusion, neurochemical and inflammatory milieu. While therapeutic hypothermia has targeted the latent and secondary phase, we now need therapies that cover the continuum of brain injury that spans hours, days, weeks and months after the initial event. Most agents have several therapeutic actions but can be broadly classified under a predominant action (e.g., free radical scavenging, anti-apoptotic, anti-inflammatory, neuroregeneration, and vascular effects). Promising early/secondary phase therapies include Allopurinol, Azithromycin, Exendin-4, Magnesium, Melatonin, Noble gases and Sildenafil. Tertiary phase agents include Erythropoietin, Stem cells and others. We review a selection of promising therapeutic agents on the translational pipeline and suggest a framework for neuroprotection and neurorestoration that targets the evolving injury.

Sodium 4-Phenylbutyrate Protects Hypoxic-Ischemic Brain Injury via Attenuating Endoplasmic Reticulum Stress in Neonatal Rats

Neonatal hypoxic-ischemic (HI) brain injury is associated with long-term neurological disorders, and protective strategies are presently scarce. Sodium 4-phenylbutyrate (4-PBA) reportedly acts as a chemical chaperone that alleviates endoplasmic reticulum (ER) stress, which plays a critical role in neurological diseases. The present study aimed to evaluate the neuroprotective effects of 4-PBA on HI-induced neonatal brain injury in a rat model, and to characterize possible underlying mechanisms. The HI brain injury model was established by ligating the left common carotid artery in 7-day-old rats, followed by exposure to 8% oxygen for 2 h. The 4-PBA or vehicle was administered by an intracerebroventricular injection 30 min before HI. The protein expression levels of ER stress markers (GRP78, ATF6, and CHOP) were detected by western blotting at 24 h after HI insult. The activation of cAMP-response element-binding protein (CREB) was evaluated by western blotting and immunofluorescence. TUNEL and Nissl staining were performed to detect the histomorphological changes in the hippocampal neurons at 24 h and 7 days, respectively, after HI injury. From days 29 to 34 after brain HI, rats underwent Morris water maze tests to assess cognitive functioning. The results showed that pretreatment with 4-PBA decreased HI-induced excessive ER stress and neuronal injury. Moreover, CREB activation might be involved in the beneficial effects of 4-PBA on HI-induced learning and memory deficits in rats. In conclusion, the present study suggested a potential therapeutic approach of ER stress inhibition in the treatment of neonatal HI brain injury.

Drug delivery platforms for neonatal brain injury

Hypoxic-ischemic encephalopathy (HIE), initiated by the interruption of oxygenated blood supply to the brain, is a leading cause of death and lifelong disability in newborns. The pathogenesis of HIE involves a complex interplay of excitotoxicity, inflammation, and oxidative stress that results in acute to long term brain damage and functional impairments. Therapeutic hypothermia is the only approved treatment for HIE but has limited effectiveness for moderate to severe brain damage; thus, pharmacological intervention is explored as an adjunct therapy to hypothermia to further promote recovery. However, the limited bioavailability and the side-effects of systemic administration are factors that hinder the use of the candidate pharmacological agents. To overcome these barriers, therapeutic molecules may be packaged into nanoscale constructs to enable their delivery. Yet, the application of nanotechnology in infants is not well examined, and the neonatal brain presents unique challenges. Novel drug delivery platforms have the potential to magnify therapeutic effects in the damaged brain, mitigate side-effects associated with high systemic doses, and evade mechanisms that remove the drugs from circulation. Encouraging pre-clinical data demonstrates an attenuation of brain damage and increased structural and functional recovery. This review surveys the current progress in drug delivery for treating neonatal brain injury.

A Review of Plant Extracts and Plant-Derived Natural Compounds in the Prevention/Treatment of Neonatal Hypoxic-Ischemic Brain Injury

Neonatal hypoxic-ischemic (HI) brain injury is one of the major drawbacks of mortality and causes significant short/long-term neurological dysfunction in newborn infants worldwide. To date, due to multifunctional complex mechanisms of brain injury, there is no well-established effective strategy to completely provide neuroprotection. Although therapeutic hypothermia is the proven treatment for hypoxic-ischemic encephalopathy (HIE), it does not completely chang outcomes in severe forms of HIE. Therefore, there is a critical need for reviewing the effective therapeutic strategies to explore the protective agents and methods. In recent years, it is widely believed that there are neuroprotective possibilities of natural compounds extracted from plants against HIE. These natural agents with the anti-inflammatory, anti-oxidative, anti-apoptotic, and neurofunctional regulatory properties exhibit preventive or therapeutic effects against experimental neonatal HI brain damage. In this study, it was aimed to review the literature in scientific databases that investigate the neuroprotective effects of plant extracts/plant-derived compounds in experimental animal models of neonatal HI brain damage and their possible underlying molecular mechanisms of action.

White matter injury in the neonatal hypoxic-ischemic brain and potential therapies targeting microglia

Neonatal hypoxic-ischemic (H-I) injury, which mainly causes neuronal damage and white matter injury (WMI), is among the predominant causes of infant morbidity (cerebral palsy, cognitive and persistent motor disabilities) and mortality. Disruptions to the oxygen and blood supply in the perinatal brain affect the cerebral microenvironment and may affect microglial activation, excitotoxicity, and oxidative stress. Microglia are significantly associated with axonal damage and myelinating oligodendrocytes, which are major pathological components of WMI. However, the effects of H-I injury on microglial functions and underlying transformation mechanisms remain poorly understood. The historical perception that these cells are major risk factors for ischemic stroke has been questioned due to our improved understanding of the diversity of microglial phenotypes and their alterable functions, which exacerbate or attenuate injuries in different regions in response to environmental instability. Unfortunately, although therapeutic hypothermia is an efficient treatment, death and disability remain the prognosis for a large proportion of neonates with H-I injury. Hence, novel neuroprotective therapies to treat WMI following H-I injury are urgently needed. Here, we review microglial mechanisms that might occur in the developing brain due to neonatal H-I injury and discuss whether microglia function as a double-edged sword in WMI. Then, we emphasize microglial heterogeneity, notably at the single-cell level, and sex-specific effects on the etiology of neurological diseases. Finally, we discuss current knowledge of strategies aiming to improve microglia modulation and remyelination following neonatal H-I injury. Overall, microglia-targeted therapy might provide novel and valuable insights into the treatment of neonatal H-I insult.

Pathophysiology of hypoxic-ischemic encephalopathy: a review of the past and a view on the future

Hypoxic-ischemic encephalopathy, also referred as HIE, is a type of brain injury or damage that is caused by a lack of oxygen to the brain during neonatal period. The incidence is approximately 1.5 cases per 1000 live births in developed countries. In low and middle-income countries, the incidence is much higher (10‒20 per 1000 live births). The treatment for neonatal HIE is hypothermia that is only partially effective (not more than 50% of the neonates treated achieve an improved outcome). HIE pathophysiology involves oxidative stress, mitochondrial energy production failure, glutaminergic excitotoxicity, and apoptosis. So, in the last years, many studies have focused on peptides that act somewhere in the pathway activated by severe anoxic injury leading to HIE. This review describes the pathophysiology of perinatal HIE and the mechanisms that could be the target of innovative HIE treatments.

lncRNA NEAT1 Binds to MiR-339-5p to Increase HOXA1 and Alleviate Ischemic Brain Damage in Neonatal Mice

Hypoxic-ischemic brain damage (HIBD) is a major cause of fatality and morbidity in neonates. However, current treatment approaches to alleviate HIBD are not effective. Various studies have highlighted the role of microRNAs (miRNAs) in various biological functions in multiple diseases. This study investigated the role of miR-339-5p in HIBD progression. Neonatal HIBD mouse model was induced by ligation of the right common carotid artery. Neuronal cell model exposed to oxygen-glucose deprivation (OGD) was also established. The miR-339-5p expression in mouse brain tissues and neuronal cells was quantified, and the effects of miR-339-5p on neuronal cell activity and apoptosis induced by hypoxia-ischemia were explored. The overexpression or knockdown of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in hippocampal neurons was used to determine the effect of lncRNA NEAT1 on the expression of miR-339-5p and homeobox A1 (HOXA1) and apoptosis. Short hairpin RNA targeting lncRNA NEAT1 and miR-339-5p antagomir were used in neonatal HIBD mice to identify their roles in HIBD. Our results revealed that miR-339-5p was downregulated in neonatal HIBD mice and neuronal cells exposed to OGD. Downregulated miR-339-5p promoted neuronal cell viability and suppressed apoptosis during hypoxia-ischemia. Moreover, lncRNA NEAT1 competitively bound to miR-339-5p to increase HOXA1 expression and inhibited neuronal cell apoptosis under hypoxic-ischemic conditions. The key observations of the current study present evidence demonstrating that lncRNA NEAT1 upregulated HOXA1 to alleviate HIBD in mice by binding to miR-339-5p.

Update on the current management of newborns with neonatal encephalopathy

Hypoxic-ischemic encephalopathy is a subtype of neonatal encephalopathy and a major contributor to global neonatal morbidity and mortality. Despite advances in obstetric and neonatal care there are still challenges in accurate determination of etiology of neonatal encephalopathy. Thus, identification of intrapartum risk factors and comprehensive evaluation of the neonate is important to determine the etiology and severity of neonatal encephalopathy. In developed countries, therapeutic hypothermia as a standard of care therapy for neonates with hypoxic-ischemic encephalopathy has proven to decrease incidence of death and neurodevelopmental disabilities, including cerebral palsy in surviving children. Advances in neuroimaging, brain monitoring modalities, and biomarkers of brain injury have improved the ability to diagnose, monitor, and treat newborns with encephalopathy. However, challenges remain in early identification of neonates at risk for hypoxic-ischemic brain injury, and determination of the timing and extent of brain injury. Using imaging studies such as Neonatal MRI and MR spectroscopy have proven to be most useful in predicting outcomes in infants with encephalopathy within the first week of life, although comprehensive neurodevelopmental assessments still remains the gold standard for determining long term outcomes. Future studies are needed to identify other newborns with encephalopathy that might benefit from therapeutic hypothermia and to determine the efficacy of other adjunctive neuroprotective strategies. This review focuses on newer evidence and advances in diagnoses and management of infants with neonatal encephalopathy, including novel therapies, as well as prognostication of outcomes to childhood.

Mechanism and Treatment Related to Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy

Hypoxic ischemic encephalopathy (HIE) is a type of neonatal brain injury, which occurs due to lack of supply and oxygen deprivation to the brain. It is associated with a high morbidity and mortality rate. There are several therapeutic strategies that can be used to improve outcomes in patients with HIE. These include cell therapies such as marrow mesenchymal stem cells (MSCs) and umbilical cord blood stem cells (UCBCs), which are being incorporated into the new protocols for the prevention of ischemic brain damage. The focus of this review is to discuss the mechanism of oxidative stress in HIE and summarize the current available treatments for HIE. We hope that a better understanding of the relationship between oxidative stress and HIE will provide new insights on the potential therapy of this devastating condition.

Recent Advances in Rational Diagnosis and Treatment of Normal Pressure Hydrocephalus: A Critical Appraisal on Novel Diagnostic, Therapy Monitoring and Treatment Modalities

BACKGROUND

Normal pressure hydrocephalus (NPH) is a critical brain disorder in which excess Cerebrospinal Fluid (CSF) is accumulated in the brain's ventricles causing damage or disruption of the brain tissues. Amongst various signs and symptoms, difficulty in walking, slurred speech, impaired decision making and critical thinking, and loss of bladder and bowl control are considered the hallmark features of NPH.

OBJECTIVE

The current review was aimed to present a comprehensive overview and critical appraisal of majorly employed neuroimaging techniques for rational diagnosis and effective monitoring of the effectiveness of the employed therapeutic intervention for NPH. Moreover, a critical overview of recent developments and utilization of pharmacological agents for the treatment of hydrocephalus has also been appraised.

RESULTS

Considering the complications associated with the shunt-based surgical operations, consistent monitoring of shunting via neuroimaging techniques hold greater clinical significance. Despite having extensive applicability of MRI and CT scan, these conventional neuroimaging techniques are associated with misdiagnosis or several health risks to patients. Recent advances in MRI (i.e., Sagittal-MRI, coronal-MRI, Time-SLIP (time-spatial-labeling-inversion-pulse), PC-MRI and diffusion-tensor-imaging (DTI)) have shown promising applicability in the diagnosis of NPH. Having associated with several adverse effects with surgical interventions, non-invasive approaches (pharmacological agents) have earned greater interest of scientists, medical professional, and healthcare providers. Amongst pharmacological agents, diuretics, isosorbide, osmotic agents, carbonic anhydrase inhibitors, glucocorticoids, NSAIDs, digoxin, and gold-198 have been employed for the management of NPH and prevention of secondary sensory/intellectual complications.

CONCLUSION

Employment of rational diagnostic tool and therapeutic modalities avoids misleading diagnosis and sophisticated management of hydrocephalus by efficient reduction of Cerebrospinal Fluid (CSF) production, reduction of fibrotic and inflammatory cascades secondary to meningitis and hemorrhage, and protection of brain from further deterioration.

MicroRNA-210 Downregulates ISCU and Induces Mitochondrial Dysfunction and Neuronal Death in Neonatal Hypoxic-Ischemic Brain Injury

Neonatal hypoxic-ischemic (HI) brain injury causes significant mortality and long-term neurologic sequelae. We previously demonstrated that HI significantly increased microRNA-210 (miR-210) in the neonatal rat brain and inhibition of brain endogenous miR-210 was neuroprotective in HI brain injury. However, the molecular mechanisms underpinning this neuroprotection remain unclear. Using both in vivo and in vitro models, herein we uncover a novel mechanism mediating oxidative brain injury after neonatal HI, in which miR-210 induces mitochondrial dysfunction via downregulation of iron-sulfur cluster assembly protein (ISCU). Inhibition of miR-210 significantly ameliorates mitochondrial dysfunction, oxidative stress, and neuronal loss in the neonatal brain subjected to HI, as well as in primary cortical neurons exposed to oxygen-glucose deprivation (OGD). These effects are mediated through ISCU, in that miR-210 mimic decreases ISCU abundance in the brains of rat pups and primary cortical neurons, and inhibition of miR-210 protects ISCU against HI in vivo or OGD in vitro. Deletion of miR-210 binding sequences at the 3'UTR of ISCU transcript ablates miR-210-induced downregulation of ISCU protein abundance in PC12 cells. In primary cortical neurons, miR-210 mimic or silencing ISCU results in mitochondrial dysfunction, reactive oxygen species production, and activation of caspase-dependent death pathways. Of importance, knockdown of ISCU increases HI-induced injury in the neonatal rat brain and counteracts the neuroprotection of miR-210 inhibition. Therefore, miR-210 by downregulating ISCU and inducing mitochondrial dysfunction in neurons is a potent contributor of oxidative brain injury after neonatal HI.

Neuroprotective Role of Hypothermia in Hypoxic-ischemic Brain Injury: Combined Therapies using Estrogen

Hypoxic-ischemic brain injury is a complex network of factors, which is mainly characterized by a decrease in levels of oxygen concentration and blood flow, which lead to an inefficient supply of nutrients to the brain. Hypoxic-ischemic brain injury can be found in perinatal asphyxia and ischemic-stroke, which represent one of the main causes of mortality and morbidity in children and adults worldwide. Therefore, knowledge of underlying mechanisms triggering these insults may help establish neuroprotective treatments. Selective Estrogen Receptor Modulators and Selective Tissue Estrogenic Activity Regulators exert several neuroprotective effects, including a decrease of reactive oxygen species, maintenance of cell viability, mitochondrial survival, among others. However, these strategies represent a traditional approach of targeting a single factor of pathology without satisfactory results. Hence, combined therapies, such as the administration of therapeutic hypothermia with a complementary neuroprotective agent, constitute a promising alternative. In this sense, the present review summarizes the underlying mechanisms of hypoxic-ischemic brain injury and compiles several neuroprotective strategies, including Selective Estrogen Receptor Modulators and Selective Tissue Estrogenic Activity Regulators, which represent putative agents for combined therapies with therapeutic hypothermia.

Caspase-3 Inhibition Attenuates the Cytopathic Effects of EV71 Infection

Previous studies demonstrate that human enterovirus 71 (EV71), a primary causative agent for hand, foot, and mouth disease, activates caspase-3 through the non-structural viral 3C protein to induce host cell apoptosis; however, until now it was unclear how 3C activates caspase-3 and how caspase-3 activation affects viral production. Our results demonstrate that 3C binds caspase-8 and caspase-9 but does not directly bind caspase-3 to activate them, and that the proteolytic activity of 3C is required by the activation of caspase-8, caspase-9, and caspase-3. Inhibition of caspase-3 activity attenuates apoptosis in 3C-transfected cells. Furthermore, caspase-3 inhibitor protects host cells from the cytopathic effect of EV71 infection and prevents cell cycle arrest, which is known to be favored for EV71 viral replication. Inhibition of caspase-3 activity decreases EV71 viral protein expression and viral production, but has no effect on viral entry, replication, even polyprotein translation. Therefore, caspase-3 is exploited functionally by EV71 to facilitate its production, which suggests a novel therapeutic approach for the treatment and prevention of hand, foot, and mouth disease.

Protection of melatonin in experimental models of newborn hypoxic-ischemic brain injury through MT1 receptor

The function of melatonin as a protective agent against newborn hypoxic-ischemic (H-I) brain injury is not yet well studied, and the mechanisms by which melatonin causes neuroprotection in neurological diseases are still evolving. This study was designed to investigate whether expression of MT1 receptors is reduced in newborn H-I brain injury and whether the protective action of melatonin is by alterations of the MT1 receptors. We demonstrated that there was significant reduction in MT1 receptors in ischemic brain of mouse pups in vivo following H-I brain injury and that melatonin offers neuroprotection through upregulation of MT1 receptors. The role of MT1 receptors was further supported by observation of increased mortality in MT1 knockout mice following H-I brain injury and the reversal of the inhibitory role of melatonin on mitochondrial cell death pathways by the melatonin receptor antagonist, luzindole. These data demonstrate that melatonin mediates its neuroprotective effect in mouse models of newborn H-I brain injury, at least in part, by the restoration of MT1 receptors, the inhibition of mitochondrial cell death pathways and the suppression of astrocytic and microglial activation.

Apurinic/apyrimidinic endonuclease 1 (APE1) contributes to resveratrol‑induced neuroprotection against oxygen‑glucose deprivation and re‑oxygenation injury in HT22 cells: Involvement in reducing oxidative DNA damage

Resveratrol, a naturally occurring polyphenolic compound, exhibits a neuroprotective role in models of central nervous system diseases, including cerebral ischemia/reperfusion injury. Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunctional enzyme that contributes to base excision repair of oxidative DNA damage and redox activation of transcription factors, associated with neuronal survival against hypoxic‑ischemic injury. It was hypothesized that resveratrol protects HT22 cells against oxygen‑glucose deprivation and re‑oxygenation (OGD/R)‑induced injuries through upregulation of APE1. It was demonstrated that resveratrol pretreatment significantly increased the viability of HT22 cells and decreased the release of lactate dehydrogenase (LDH), accompanied by the upregulation of APE1 mRNA, and protein levels, as well as the activity of APE1 under OGD/R conditions. In addition, resveratrol reversed OGD/R‑induced oxidative DNA damage as evidenced by the decreases in the levels of 8‑hydroxy‑2'‑deoxyguanosine and APE sites. However, APE1 knockdown using short hairpin RNA sequence targeting APE1 abolished resveratrol‑elicited beneficent effects against OGD/R‑induced cytotoxicity and oxidative stress. This was indicated by decreased cell viability, superoxide dismutase activity and glutathione levels, and increased LDH release and reactive oxygen species levels. The results of the present study indicate that APE1 contributes to the protective effects of resveratrol against neonatal hypoxic‑ischemic brain injuries, and suggest that DNA repair enzymes, including APE1, may be a unique strategy for neuroprotection against this disease.

A Controversial Medicolegal Issue: Timing the Onset of Perinatal Hypoxic-Ischemic Brain Injury

Perinatal hypoxic-ischemic brain injury, as a result of chronic, subacute, and acute insults, represents the pathological consequence of fetal distress and birth or perinatal asphyxia, that is, “nonreassuring fetal status.” Hypoxic-ischemic injury (HII) is typically characterized by an early phase of damage, followed by a delayed inflammatory local response, in an apoptosis-necrosis continuum. In the early phase, the cytotoxic edema and eventual acute lysis take place; with reperfusion, additional damage should be assigned to excitotoxicity and oxidative stress. Finally, a later phase involves all the inflammatory activity and long-term neural tissue repairing and remodeling. In this model mechanism, loss of mitochondrial function is supposed to be the hallmark of secondary injury progression, and autophagy which is lysosome-mediated play a role in enhancing brain injury. Early-induced molecules driven by hypoxia, as chaperonins HSPs and ORP150, besides common markers for inflammatory responses, have predictive value in timing the onset of neonatal HII; on the other hand, clinical biomarkers for HII diagnosis, as CK-BB, LDH, S-100beta, and NSE, could be useful to predict outcomes.

Therapeutic effects of L-Cysteine in newborn mice subjected to hypoxia-ischemia brain injury via the CBS/H2S system: Role of oxidative stress and endoplasmic reticulum stress

Neonatal hypoxic-ischemic (HI) injury is a major cause of neonatal death and neurological dysfunction. H₂S has been shown to protect against hypoxia-induced injury and apoptosis of neurons. L-Cysteine is catalyzed by cystathionine-β-synthase (CBS) in the brain and sequentially produces endogenous H₂S. The present study was designed to investigate whether L-Cysteine could attenuate the acute brain injury and improve neurobehavioral outcomes following HI brain injury in neonatal mice by releasing endogenous H₂S. L-Cysteine treatment significantly attenuated brain edema and decreased infarct volume and neuronal cell death, as shown by a decrease in the Bax/Bcl-2 ratio, suppression of caspase-3 activation, and reduced phosphorylation of Akt and ERK at 72 h after HI. Additionally, L-Cysteine substantially up-regulated NF-E2-related factor 2 and heme oxygenase-1 expression. L-Cysteine also decreased endoplasmic reticulum (ER) stress-associated pro-apoptotic protein expression. Furthermore, L-Cysteine had long-term effects by protecting against the loss of ipsilateral brain tissue and improving neurobehavioral outcomes. Importantly, pre-treatment with a CBS inhibitor significantly attenuated the neuroprotection of L-Cysteine on HI insult. Thus, L-Cysteine exerts neuroprotection against HI-induced injury in neonates via the CBS/H₂S pathway, mediated in part by anti-apoptotic effects and reduced oxidative stress and ER stress. Thus, L-Cysteine may be a promising treatment for HI.

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L-Cysteine administration at 24 h after HI insult has neuroprotective effect.

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L-Cysteine administration attenuated HI-induced oxidative stress and ER stress.

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L-Cysteine administration had long-term effects in improving neurobehavioral function at 14 and 28 days after HI insult.

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Pre-treatment with a CBS inhibitor significantly attenuated the neuroprotection of L-Cysteine on HI in neonatal mice.

Inhibition of endoplasmic reticulum stress is involved in the neuroprotective effect of aFGF in neonatal hypoxic-ischaemic brain injury

Acidic fibroblast growth factor (aFGF) has been shown to exert neuroprotective effects in experimental models and human patients. In this study, we investigated whether aFGF intranasal-treatment protected against neonatal hypoxic-ischaemic brain injury and evaluated the role of endoplasmic reticulum stress. The Rice-Vannucci model of neonatal hypoxic-ischaemic brain injury was used in 7-day-old rats, which were subjected to unilateral carotid artery ligation followed by 2.5 h of hypoxia. Intranasal aFGF or vehicle was administered immediately after hypoxic-ischaemic injury (100 ng/g) and then twice a day for 1 week to evaluate the long-term effects. Here we reported that intranasal-treatment with aFGF significantly reduced hypoxic-ischaemic brain infarct volumes and the protective effects were at least partially via inhibiting endoplasmic reticulum stress. In addition, aFGF exerted long-term neuroprotective effects against brain atrophy and neuron loss at 7-day after injury. Our data indicate that therapeutic strategies targeting endoplasmic reticulum stress may be promising to the treatment of neonatal hypoxic-ischaemic brain injury.

Rheum emodin inhibits enterovirus 71 viral replication and affects the host cell cycle environment

Human enterovirus 71 (EV71) is the primary causative agent of recent large-scale outbreaks of hand, foot, and mouth disease (HFMD) in Asia. Currently, there are no drugs available for the prevention and treatment of HFMD. In this study, we compared the anti-EV71 activities of three natural compounds, rheum emodin, artemisinin and astragaloside extracted from Chinese herbs Chinese rhubarb, Artemisia carvifolia and Astragalus, respectively, which have been traditionally used for the treatment and prevention of epidemic diseases. Human lung fibroblast cell line MRC5 was mock-infected or infected with EV71, and treated with drugs. The cytotoxicity of the drugs was detected with MTT assay. The cytopathic effects such as cell death and condensed nuclei were morphologically observed. The VP1-coding sequence required for EV71 genome replication was assayed with qRT-PCR. Viral protein expression was analyzed with Western blotting. Viral TCID50 was determined to evaluate EV71 virulence. Flow cytometry analysis of propidium iodide staining was performed to analyze the cell cycle distribution of MRC5 cells. Rheum emodin (29.6 μmol/L) effectively protected MRC5 cells from EV71-induced cytopathic effects, which resulted from the inhibiting viral replication: rheum emodin treatment decreased viral genomic levels by 5.34-fold, viral protein expression by less than 30-fold and EV71 virulence by 0.33107-fold. The fact that inhibition of rheum emodin on viral virulence was much stronger than its effects on genomic levels and viral protein expression suggested that rheum emodin inhibited viral maturation. Furthermore, rheum emodin treatment markedly diminished cell cycle arrest at S phase in MRC5 cells, which was induced by EV71 infection and favored the viral replication. In contrast, neither astragaloside (50 μmol/L) nor artemisinin (50 μmol/L) showed similar anti-EV71 activities. Among the three natural compounds tested, rheum emodin effectively suppressed EV71 viral replication, thus is a candidate anti-HFMD drug.

25 years of research on global asphyxia in the immature rat brain

Hypoxic-ischemic encephalopathy remains a common cause of brain damage in neonates. Preterm infants have additional complications, as prematurity by itself increases the risk of encephalopathy. Currently, therapy for this subset of asphyxiated infants is limited to supportive care. There is an urgent need for therapies in preterm infants - and for representative animal models for preclinical drug development. In 1991, a novel rodent model of global asphyxia in the preterm infant was developed in Sweden. This method was based on the induction of asphyxia during the birth processes itself by submerging pups, still in the uterine horns, in a water bath followed by C-section. This insult occurs at a time-point when the rodent brain maturity resembles the brain of a 22-32 week old human fetus. This model has developed over the past 25 years as an established model of perinatal global asphyxia in the early preterm brain. Here we summarize the knowledge gained on the short- and long-term neuropathological and behavioral effects of asphyxia on the immature central nervous system.

Role of Antioxidants in Neonatal Hypoxic-Ischemic Brain Injury: New Therapeutic Approaches

Hypoxic-ischemic brain damage is an alarming health and economic problem in spite of the advances in neonatal care. It can cause mortality or detrimental neurological disorders such as cerebral palsy, motor impairment and cognitive deficits in neonates. When hypoxia-ischemia occurs, a multi-faceted cascade of events starts out, which can eventually cause cell death. Lower levels of oxygen due to reduced blood supply increase the production of reactive oxygen species, which leads to oxidative stress, a higher concentration of free cytosolic calcium and impaired mitochondrial function, triggering the activation of apoptotic pathways, DNA fragmentation and cell death. The high incidence of this type of lesion in newborns can be partly attributed to the fact that the developing brain is particularly vulnerable to oxidative stress. Since antioxidants can safely interact with free radicals and terminate that chain reaction before vital molecules are damaged, exogenous antioxidant therapy may have the potential to diminish cellular damage caused by hypoxia-ischemia. In this review, we focus on the neuroprotective effects of antioxidant treatments against perinatal hypoxic-ischemic brain injury, in the light of the most recent advances.

Neuroprotective Effects of a Smoothened Receptor Agonist against Early Brain Injury after Experimental Subarachnoid Hemorrhage in Rats

The sonic hedgehog (Shh) signaling pathway plays a fundamental role in the central nervous system (CNS) development, but its effects on neural cell survival and brain repair after subarachnoid hemorrhage (SAH) has not been well-investigated. The present study was undertaken to evaluate the influence of an agonist of the Shh co-receptor Smoothened (Smo), purmorphamine (PUR), on early brain injury (EBI) as well as the underlying mechanisms after SAH. PUR was administered via an intraperitoneal injection with a dose of 0.5, 1, and 5 mg/kg at 2, 6, 24, and 46 h after SAH in rat model. The results showed that PUR treatment significantly ameliorated brain edema, improved neurobehavioral function, and attenuated neuronal cell death in the prefrontal cortex (PFC), associated with a decrease in Bax/Bcl-2 ratio and suppression of caspase-3 activation at 48 h after SAH. PUR also promoted phospho-ERK levels. Additionally, PUR treatment markedly decreased MDA concentration accompanied with the elevation in the expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase-1 in PFC. Notably, PUR treatment significantly reversed the changes of Shh pathway mediators containing Patched, Gli1, and Shh by SAH insult, and the neuroprotection of PUR on SAH was blocked by Smo antagonist cyclopamine. These results indicated that PUR exerts neuroprotection against SAH-evoked injury in rats, mediated in part by anti-apoptotic and anti-oxidant mechanism, up-regulating phospho-ERK levels, mediating Shh signaling molecules in the PFC.

Characterisation of neuroprotective efficacy of modified poly-arginine-9 (R9) peptides using a neuronal glutamic acid excitotoxicity model

In a recent study, we highlighted the importance of cationic charge and arginine residues for the neuroprotective properties of poly-arginine and arginine-rich peptides. In this study, using cortical neuronal cultures and an in vitro glutamic acid excitotoxicity model, we examined the neuroprotective efficacy of different modifications to the poly-arginine-9 peptide (R9). We compared an unmodified R9 peptide with R9 peptides containing the following modifications: (i) C-terminal amidation (R9-NH2); (ii) N-terminal acetylation (Ac-R9); (iii) C-terminal amidation with N-terminal acetylation (Ac-R9-NH2); and (iv) C-terminal amidation with D-amino acids (R9D-NH2). The three C-terminal amidated peptides (R9-NH2, Ac-R9-NH2, and R9D-NH2) displayed neuroprotective effects greater than the unmodified R9 peptide, while the N-terminal acetylated peptide (Ac-R9) had reduced efficacy. Using the R9-NH2 peptide, neuroprotection could be induced with a 10 min peptide pre-treatment, 1-6 h before glutamic acid insult, or when added to neuronal cultures up to 45 min post-insult. In addition, all peptides were capable of reducing glutamic acid-mediated neuronal intracellular calcium influx, in a manner that reflected their neuroprotective efficacy. This study further highlights the neuroprotective properties of poly-arginine peptides and provides insight into peptide modifications that affect efficacy.

Repression of neuronal nitric oxide (nNOS) synthesis by MTA1 is involved in oxidative stress-induced neuronal damage

The Metastasis-associated protein 1 (MTA1) coregulator, an essential component of the nucleosome remodeling and deacetylase (NuRD) complex, potentiates neuroprotective effects against ischemia/reperfusion (I/R) injury. But the underlying mechanism(s) remain largely unknown. Here, we discovered that neuronal MTA1 was a target of oxidative stress, and stimulation of neurons with oxygen glucose deprivation (OGD) treatment significantly inhibited MTA1 expression. Additionally, MTA1 depletion augmented ischemic oxidative stress and thus promoted oxidative stress-induced neuronal cell death by OGD. While studying the impact of MTA1 status on global neuronal gene expression, we unexpectedly discovered that MTA1 may modulate OGD-induced neuronal damage via regulation of distinct nitric oxide synthase (NOS) (namely neuronal NOS, nNOS) signaling. We provided in vitro evidence that NOS1 is a chromatin target of MTA1 in OGD-insulted neurons. Mechanistically, neuronal ischemia-mediated repression of NOS1 expression is accompanied by the enhanced recruitment of MTA1 along with histone deacetylases (HDACs) to the NOS1 promoter, which could be effectively blocked by a pharmacological inhibitor of the HDACs. These findings collectively reveal a previously unrecognized, critical homeostatic role of MTA1, both as a target and as a component of the neuronal oxidative stress, in the regulation of acute neuronal responses against brain I/R damage. Our study also provides a molecular mechanistic explanation for the previously reported neurovascular protection by selective nNOS inhibitors.

[Prevention and treatment of energy failure in neonates with hypoxic-ischemic encephalopathy]

Hypoxic-ischemic encephalopathy (HIE) in neonates is the brain injury caused by perinatal asphyxia or hypoxia and is a major cause of death in neonates and nervous system dysfunction in infants and young children. Although to a certain degree, mild hypothermia therapy reduces the mortality of infants with moderate to severe HIE, it cannot achieve the expected improvements in nervous system dysfunction. Hence, it is of vital importance to search for effective therapeutic methods for HIE. The search for more therapies and better preventive measures based on the pathogenesis of HIE has resulted in much research. As an important link in the course of HIE, energy failure greatly affects the development and progression of HIE. This article reviews the research advances in the treatment and prevention of energy failure in the course of HIE.

Preventing deaths from complications of labour and delivery

The process of labour and delivery remains an unnecessary and preventable cause of death of women and babies around the world. Although the rates of maternal and perinatal death are declining, there are large disparities between rich and poor countries, and sub-Saharan Africa has not seen the scale of decline as seen elsewhere. In many areas, maternity services remain sparse and under-equipped, with insufficient and poorly trained staff. Priorities for reducing the mortality burden are provision of safe caesarean section, prevention of sepsis and appropriate care of women in labour in line with the current best practices, appropriately and affordably delivered. A concern is that large-scale recourse to caesarean delivery has its own dangers and may present new dominant causes for maternal mortality. An area of current neglect is newborn care. However, innovative training methods and appropriate technologies offer opportunities for affordable and effective newborn resuscitation and follow-up management in low-income settings.

Erythropoietin Pathway: A Potential Target for the Treatment of Depression

During the past decade, accumulating evidence from both clinical and experimental studies has indicated that erythropoietin may have antidepressant effects. In addition to the kidney and liver, many organs have been identified as secretory tissues for erythropoietin, including the brain. Its receptor is expressed in cerebral and spinal cord neurons, the hypothalamus, hippocampus, neocortex, dorsal root ganglia, nerve axons, and Schwann cells. These findings may highlight new functions for erythropoietin, which was originally considered to play a crucial role in the progress of erythroid differentiation. Erythropoietin and its receptor signaling through JAK2 activate multiple downstream signaling pathways including STAT5, PI3K/Akt, NF-κB, and MAPK. These factors may play an important role in inflammation and neuroprogression in the nervous system. This is particularly true for the hippocampus, which is possibly related to learning, memory, neurocognitive deficits and mood alterations. Thus, the influence of erythropoietin on the downstream pathways known to be involved in the treatment of depression makes the erythropoietin-related pathway an attractive target for the development of new therapeutic approaches. Focusing on erythropoietin may help us understand the pathogenic mechanisms of depression and the molecular basis of its treatment.

Nonsurgical therapy for hydrocephalus: a comprehensive and critical review

Pharmacological interventions have been tested experimentally and clinically to prevent hydrocephalus and avoid the need for shunting beginning in the 1950s. Clinical trials of varied quality have not demonstrated lasting and convincing protective effects through manipulation of cerebrospinal fluid production, diuresis, blood clot fibrinolysis, or manipulation of fibrosis in the subarachnoid compartment, although there remains some promise in the latter areas. Acetazolamide bolus seems to be useful for predicting shunt response in adults with hydrocephalus. Neuroprotection in the situation of established hydrocephalus has been tested experimentally beginning more recently. Therapies designed to modify blood flow or pulsation, reduce inflammation, reduce oxidative damage, or protect neurons are so far of limited success; more experimental work is needed in these areas. As has been recommended for preclinical studies in stroke and brain trauma, stringent conditions should be met for preclinical studies in hydrocephalus.

Anticytokine Autoantibodies: Association with Infection and Immune Dysregulation

The association of autoantibodies to cytokines with immune deficiency, autoimmunity and/or immune dysregulation is increasingly being recognized. For example, autoantibodies to interferon gamma have been found to be associated with chronic, treatment refractory infections with intracellular organisms such as mycobacteria, autoantibodies to interleukin 17 with chronic mucocutaneous candidiasis, and anti-interferon alpha autoantibodies with systemic lupus erythematosus. While low titer autoantibodies to these and other cytokines may be detected in normal individuals, patients with infectious or autoimmune manifestations tend to have high titer autoantibodies that may block or potentiate the function of the respective cytokine. Recognition of these autoantibodies is important because it may direct treatment toward a combination of adjunctive immunotherapy to modulate the autoantibody level while continuing with appropriate anti-microbial therapy. This review focuses on the anti-cytokine autoantibodies documented to date, their autoimmune, immune dysregulation and infectious disease associations, methods for detection of these antibodies and potential treatment options.