Brain injury patterns in hypoxic ischemic encephalopathy of term neonates

Neuroprotective strategies for neonatal hypoxic-ischemic brain damage: Current status and challenges

Neonatal hypoxic-ischemic brain damage (HIBD) is a prominent contributor to both immediate mortality and long-term impairment in newborns. The elusive nature of the underlying mechanisms responsible for neonatal HIBD presents a significant obstacle in the effective clinical application of numerous pharmaceutical interventions. This comprehensive review aims to concentrate on the potential neuroprotective agents that have demonstrated efficacy in addressing various pathogenic factors associated with neonatal HIBD, encompassing oxidative stress, calcium overload, mitochondrial dysfunction, endoplasmic reticulum stress, inflammatory response, and apoptosis. In this review, we conducted an analysis of the precise molecular pathways by which these drugs elicit neuroprotective effects in animal models of neonatal hypoxic-ischemic brain injury (HIBD). Our objective was to provide a comprehensive overview of potential neuroprotective agents for the treatment of neonatal HIBD in animal experiments, with the ultimate goal of enhancing the feasibility of clinical translation and establishing a solid theoretical foundation for the clinical management of neonatal HIBD.

Clinical characteristics and long-term neurodevelopmental outcomes of leukomalacia in preterm infants and term infants: a cohort study

BACKGROUND

Leukomalacia is a serious form of neonatal brain injury that often leads to neurodevelopmental impairment, and studies on neonatal leukomalacia and its long-term outcomes are lacking. The aim of this study was to analyze the clinical manifestations, imaging features, and long-term neurodevelopmental outcomes in preterm infants and term infants with leukomalacia.

METHODS

Newborns diagnosed with leukomalacia by head magnetic resonance imaging (MRI) and who were admitted to intensive care units from January 2015 to June 2020 were enrolled. All infants were followed up to June 2022 (2-7 years old), and their neurodevelopmental outcomes were evaluated. The clinical data and long- term outcomes of preterm infants and term infants was analyzed by Chi-square tests.

RESULTS

A total of 218 surviving infants with leukomalacia including 114 preterm infants and 104 term infants completed the follow-up. The major typesof leukomalacia on MRI were periventricular leukomalacia in the preterm group and subcortical cystic leukomalacia in the term group, respectively (χ2 = 55.166; p < 0.001). When followed up to 2-7 years old, the incidence of neurodevelopmental impairment in the preterm group and term group was not significantly different (χ2 = 0.917; p = 0.338). However, the incidence of cerebral palsy (CP) in the preterm group was significantly higher (χ2 = 4.896; p = 0.027), while the incidence of intellectual disability (ID) (χ2 = 9.445; p = 0.002), epilepsy (EP) (χ2 = 23.049; p < 0.001), and CP combined with ID andEP (χ2 = 4.122; p = 0.042) was significantly lower than that in the term group.

CONCLUSIONS

Periventricular leukomalacia mainly occurred in preterm infants while subcortical cystic leukomalacia was commonly seen in term infants. Although the long-term neurodevelopmental outcomes of leukomalacia were both poor, preterm infants were more prone to CP, while term infants were more prone to ID, EP, and the combination of CP with ID and EP.

Selectively compromised inner retina function following hypoxic-ischemic encephalopathy in mice: A noninvasive measure of severity of the injury

The intricate system of connections between the eye and the brain implies that there are common pathways for the eye and brain that get activated following injury. Hypoxia-ischemia (HI) related encephalopathy is a consequence of brain injury caused by oxygen and blood flow deprivation that may result in visual disturbances and neurodevelopmental disorders in surviving neonates. We have previously shown that the tyrosine receptor kinase B (TrkB) agonist/modulator improves neuronal survival and long-term neuroprotection in a sexually differential way. In this study, we tested the hypotheses that; 1) TrkB agonist therapy improves the visual function in a sexually differential way; 2) Visual function detected by electroretinogram (ERG) correlates with severity of brain injury detected by magnetic resonance (MRI) imaging following neonatal HI in mice. To test our hypotheses, we used C57/BL6 mice at postnatal day (P) 9 and subjected them to either Vannucci's rodent model of neonatal HI or sham surgery. ERG was performed at P 30, 60, and 90. MRI was performed following the completion of the ERG. ERG in these mice showed that the a-wave is normal, but the b-wave amplitude is severely abnormal, reducing the b/a wave amplitude ratio. Inner retina function was found to be perturbed as we detected severely attenuated oscillatory potential after HI. No sex differences were detected in the injury and severity pattern to the retina as well as in response to 7,8-DHF therapy. Strong correlations were detected between the percent change in b/a ratio and percent hemispheric/hippocampal tissue loss obtained by MRI, suggesting that ERG is a valuable noninvasive tool that can predict the long-term severity of brain injury.