Knockdown of NADPH oxidase 4 reduces mitochondrial oxidative stress and neuronal pyroptosis following intracerebral hemorrhage

Intracerebral hemorrhage is often accompanied by oxidative stress induced by reactive oxygen species,which causes abnormal mitochondrial function and secondary reactive oxygen species generation.This creates a vicious cycle leading to reactive oxygen species accumulation,resulting in progression of the pathological process.Therefore,breaking the cycle to inhibit reactive oxygen species accumulation is critical for reducing neuronal death after intracerebral hemorrhage.Our previous study found that increased expression of nicotinamide adenine dinucleotide phosphate oxidase 4(NADPH oxidase 4,NOX4)led to neuronal apoptosis and damage to the blood-brain barrier after intracerebral hemorrhage.The purpose of this study was to investigate the role of NOX4 in the circle involving the neuronal tolerance to oxidative stress,mitochondrial reactive oxygen species and modes of neuronal death other than apoptosis after intracerebral hemorrhage.We found that NOX4 knockdown by adeno-associated virus(AAV-NOX4)in rats enhanced neuronal tolerance to oxidative stress,enabling them to better resist the oxidative stress caused by intracerebral hemorrhage.Knockdown of NOX4 also reduced the production of reactive oxygen species in the mitochondria,relieved mitochondrial damage,prevented secondary reactive oxygen species accumulation,reduced neuronal pyroptosis and contributed to relieving secondary brain injury after intracerebral hemorrhage in rats.Finally,we used a mitochondria-targeted superoxide dismutase mimetic to explore the relationship between reactive oxygen species and NOX4.The mitochondria-targeted superoxide dismutase mimetic inhibited the expression of NOX4 and neuronal pyroptosis,which is similar to the effect of AAV-NOX4.This indicates that NOX4 is likely to be an important target for inhibiting mitochondrial reactive oxygen species production,and NOX4 inhibitors can be used to alleviate oxidative stress response induced by intracerebral hemorrhage.

Lung-protective Ventilation in Patients with Brain Injury： A Multicenter Cross-sectional Study and Questionnaire Survey in China

Background： Over the years, the mechanical ventilation （MV） strategy has changed worldwide. The aim of the present study was to describe the ventilation practices, particularly lung-protective ventilation （LPV）, among brain-injured patients in China. Methods： This study was a multicenter, 1-day, cross-sectional study in 47 Intensive Care Units （ICUs） across China. Mechanically ventilated patients （18 years and older） with brain injury in a participating ICU during the time of the study, including traumatic brain injury, stroke, postoperation with intracranial tumor, hypoxic-ischemic encephalopathy, intracranial infection, and idiopathic epilepsy, were enrolled. Demographic data, primary diagnoses, indications for MV, MV modes and settings, and prognoses on the 60th day were collected. Multivariable logistic analysis was used to assess factors that might affect the use of LPV. Results： A total of 104 patients were enrolled in the present study, 87 （83.7%） of whom were identified with severe brain injury based on a Glasgow Coma Scale 〈8 points. Synchronized intermittent mandatory ventilation （SIMV） was the most frequent ventilator mode, accounting for 46.2% of the entire cohort. The median tidal volume was set to 8.0 ml/kg （interquartile range [IQR], 7.0-8.9 ml/kg） of the predicted body weight; 50 （48.1%） patients received LPV. The median positive end-expiratory pressure （PEEP） was set to 5 cmH20 （IQR, 5-5 cmH20）. No PEEP values were higher than 10 cmH20. Compared with partially mandatory ventilation, supportive and spontaneous ventilation practices were associated with LPV. There were no significant differences in mortality and MV duration between patients subjected to LPV and those were not. Conclusions： Among brain-injured patients in China, SIMV was the most frequent ventilation mode. Nearly one-half of the brain-injured patients received LPV. Patients under supportive and spontaneous ventilation were more likely to receive LPV.