Perinatal hypoxic-ischemic damage: review of the current treatment possibilities

Lasting mesothalamic dopamine imbalance and altered exploratory behavior in rats after a mild neonatal hypoxic event

Introduction

Adversities during the perinatal period can decrease oxygen supply to the fetal brain, leading to various hypoxic brain injuries, which can compromise the regularity of brain development in different aspects. To examine the catecholaminergic contribution to the link between an early-life hypoxic insult and adolescent behavioral aberrations, we used a previously established rat model of perinatal hypoxia but altered the hypobaric to normobaric conditions.

Methods

Exploratory and social behavior and learning abilities were tested in 70 rats of both sexes at adolescent age. Inherent vertical locomotion, sensory-motor functions and spatial learning abilities were explored in a subset of animals to clarify the background of altered exploratory behavior. Finally, the concentrations of dopamine (DA) and noradrenaline in midbrain and pons, and the relative expression of genes for DA receptors D1 and D2, and their down-stream targets (DA- and cAMP-regulated phosphoprotein, Mr 32 kDa, the regulatory subunit of protein kinase A, and inhibitor-5 of protein phosphatase 1) in the hippocampus and thalamus were investigated in 31 rats.

Results

A lesser extent of alterations in exploratory and cognitive aspects of behavior in the present study suggests that normobaric conditions mitigate the hypoxic injury compared to the one obtained under hypobaric conditions. Increased exploratory rearing was the most prominent consequence, with impaired spatial learning in the background. In affected rats, increased midbrain/pons DA content, as well as mRNA levels for DA receptors and their down-stream elements in the thalamus, but not the hippocampus, were found.

Conclusion

We can conclude that a mild hypoxic event induced long-lasting disbalances in mesothalamic DA signaling, contributing to the observed behavioral alterations. The thalamus was thereby indicated as another structure, besides the well-established striatum, involved in mediating hypoxic effects on behavior through DA signaling.

Farrerol Alleviates Hypoxic-Ischemic Encephalopathy by Inhibiting Ferroptosis in Neonatal Rats via the Nrf2 Pathway

Farrerol (FA) is a traditional Chinese herbal medicine known for its anti-inflammatory and anti-oxidative properties in various diseases. Ferroptosis is an iron-dependent oxidative stress-induced cell death. It is characterized by lipid peroxidation and glutathione depletion and is involved in neuronal injury. However, the role of FA in inhibiting ferroptosis in hypoxic-ischemic encephalopathy (HIE) and its underlying mechanisms are not yet completely elucidated. This study aimed to investigate whether FA could mediate ferroptosis and explore its function and molecular mechanism in HIE. A neonatal rat model of HIE was used, and rats were treated with FA, ML385 (a specific inhibitor of nuclear factor erythroid 2-related factor 2 [Nrf2]), or a combination of both. Neurological deficits, infarction volume, brain water content, pathological changes, and iron ion accumulation in the brain tissues were measured using the Zea-Longa scoring system and triphenyl tetrazolium chloride (TTC), hematoxylin-eosin (HE), and Perls' staining. The expression levels of GSH-Px, MDA, SOD, and ROS in brain tissues were also evaluated. Western blot analysis was performed to analyze the expression of the Nrf2 pathway and ferroptosis-related proteins. The results showed that FA administration significantly reduced neuronal damage, infarct volume, cerebral edema, and iron ion accumulation and inhibited MDA and ROS levels while promoting GSH-Px and SOD levels. FA also increased the expression levels of glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), Nrf2, and HO-1. Moreover, the combination of ML385 and FA in HIE abolished the FA protective effects. Therefore, the study concludes that FA exerts a neuroprotective effect after HIE by inhibiting oxidative stress and ferroptosis via the Nrf2 signaling pathway.

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

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

Effect of environmental enrichment on behavioral and morphological outcomes following neonatal hypoxia-ischemia in rodent models: A systematic review and meta-analysis

Neonatal hypoxia-ischemia (HI) is a major cause of mortality and morbidity in newborns and, despite recent advances in neonatal intensive care, there is no definitive treatment for this pathology. Once preclinical studies have shown that environmental enrichment (EE) seems to be a promising therapy for children with HI, the present study conducts a systematic review and meta-analysis of articles with EE in HI rodent models focusing on neurodevelopmental reflexes, motor and cognitive function as well as brain damage. The protocol was registered a priori at PROSPERO. The search was conducted in PubMed, Embase and PsycINFO databases, resulting in the inclusion of 22 articles. Interestingly, EE showed a beneficial impact on neurodevelopmental reflexes (SMD= -0.73, CI= [-0.98; -0.47], p< 0.001, I²= 0.0%), motor function (SMD= -0.55, CI= [-0.81; -0.28], p< 0.001, I²= 62.6%), cognitive function (SMD= -0.93, CI= [-1.14; -0.72], p< 0.001, I²= 27.8%) and brain damage (SMD= -0.80, CI= [-1.03; -0.58], p< 0.001, I²= 10.7%). The main factors that potentiate EE positive effects were enhanced study quality, earlier age at injury as well as earlier start and longer duration of EE exposure. Overall, EE was able to counteract the behavioral and histological damage induced by the lesion, being a promising therapeutic strategy for HI.

Neural Function Recovery and Safety of Mild Hypothermia Therapy Combined with Monosialotetrahexosylganglioside on Neonatal Asphyxia Complicated by Hypoxic Ischemic Encephalopathy

Objective

To explore the effect and safety of mild hypothermia therapy combined with monosialotetrahexosylganglioside (GM1) on neural function recovery of neonatal asphyxia complicated by hypoxic ischemic encephalopathy (HIE).

Methods

The clinical data of 90 neonates with HIE were retrospectively analyzed. According to the treatment methods, the neonates were divided into a routine group, a mild hypothermia group, and a combination group, with 30 cases in each group. The differences in neural function recovery, biochemical indexes, clinical signs recovery, efficacy, and complications were observed in the three groups after treatment.

Results

After treatment, the score of neonatal behavioral neurological assessment (NBNA) and level of superoxide dismutase (SOD) in the combination group were higher than those of the other two groups (P < 0.05). The levels of neuron-specific enolase (NSE), S-100β protein, and plasma neuropeptide Y (NPY) in the combination group were lower than those in the other two groups, and the recovery time of consciousness, muscle tension, and reflex was shorter (P < 0.05). The combination group showed higher total effective rate and lower incidence of complications as compared with the other two groups (P < 0.05).

Conclusion

Mild hypothermia therapy combined with GM1 for the treatment of neonatal asphyxia complicated by HIE can promote the recovery of neural function and reduce the incidence of complications in neonates.

[Modern possibilities of diagnosing lesions of the visual analyzer in perinatal lesions of the central nervous system in full-term and premature infants]

The article provides an overview of current neuro-ophthalmological diagnostic capabilities in patients with perinatal lesions. The main attention is paid to the diagnosis of patients with periventricular leukomalacia and peri- and intraventricular hemorrhages. The most relevant methods of neuro-ophthalmological diagnosis in hypoxic-ischemic CNS lesions are covered. The functions and peculiarities of blood supply of the germinal matrix are described. The importance of the use of optical coherence tomography and visual evoked potential recording in full-term and premature infants with visual pathway and/or visual cortex lesions in brain lesions is discussed. The conclusion emphasizes the need for an interdisciplinary approach in the examination of children with perinatal CNS lesions.

The Effect of Sulphoraphane on Brain Glucose Uptake during Neonatal Hypoxic-Ischemic Encephalopathy in Newborn Rats

Neonatal hypoxic-ischemic insult (HII) is one of the leading causes of morbidity and mortality in newborns. It has long-term consequences and represents a socioeconomic burden. It is an urgent issue in current neonatology. The aim of the present pilot study was to evaluate the possible effect of sulforaphane on brain glucose uptake expressed as 18F-fluorodeoxyglucose (18F-FDG) activity at the acute, subacute, and subchronic time intervals after the experimental perinatal HII in rats. Significant protection has been observed in the hippocampus 5 weeks after the insult as represented by normalisations of interhemispheric ratio of measured 18F-FDG activity. In conclusion, positron emission tomography (PET) with 18F-FDG revealed a protective effect of SFN on glucose metabolism in the subchronic phase after HII. Further research within the field of neonatal HII in newborn rats will be necessary.

The pharmacological treatment of epilepsy: recent advances and future perspectives

The pharmacological armamentarium against epilepsy has expanded considerably over the last three decades, and currently includes over 30 different antiseizure medications. Despite this large armamentarium, about one third of people with epilepsy fail to achieve sustained seizure freedom with currently available medications. This sobering fact, however, is mitigated by evidence that clinical outcomes for many people with epilepsy have improved over the years. In particular, physicians now have unprecedented opportunities to tailor treatment choices to the characteristics of the individual, in order to maximize efficacy and tolerability. The present article discusses advances in the drug treatment of epilepsy in the last 5 years, focusing in particular on comparative effectiveness trials of second-generation drugs, the introduction of new pharmaceutical formulations for emergency use, and the results achieved with the newest medications. The article also includes a discussion of potential future developments, including those derived from advances in information technology, the development of novel precision treatments, the introduction of disease modifying agents, and the discovery of biomarkers to facilitate conduction of clinical trials as well as routine clinical management.