A randomized,placebo‐controlled clinical trial of hydrogen/oxygen inhalation for non‐alcoholic fatty liver disease

Non‐alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide with increasing incidence consistent with obesity, type 2 diabetes and cardiovascular diseases. No approved medication was currently available for NAFLD treatment. Molecular hydrogen (H₂), an anti‐oxidative, anti‐inflammatory biomedical agent is proved to exhibit therapeutic and preventive effect in various diseases. The purpose of this study was to investigate the effect of hydrogen/oxygen inhalation on NAFLD subjects and explore the mechanism from the perspective of hepatocyte autophagy. We conducted a randomized, placebo‐controlled clinical trial of 13‐week hydrogen/oxygen inhalation (China Clinical Trial Registry [#ChiCTR‐IIR‐16009114]) including 43 subjects. We found that inhalation of hydrogen/oxygen improved serum lipid and liver enzymes. Significantly improved liver fat content detected by ultrasound and CT scans after hydrogen/oxygen inhalation was observed in moderate–severe cases. We also performed an animal experiment based on methionine and choline‐deficient (MCD) diet‐induced mice model to investigate effect of hydrogen on mouse NASH. Hydrogen/oxygen inhalation improved systemic inflammation and liver histology. Promoted autophagy was observed in mice inhaled hydrogen/oxygen and treatment with chloroquine blocked the beneficial effect of hydrogen. Moreover, molecular hydrogen inhibited lipid accumulation in AML‐12 cells. Autophagy induced by palmitic acid (PA) incubation was further promoted by 20% hydrogen incubation. Addition of 3‐methyladenine (3‐MA) partially blocked the inhibitory effect of hydrogen on intracellular lipid accumulation. Collectively, hydrogen/oxygen inhalation alleviated NAFLD in moderate–severe patients. This protective effect of hydrogen was possibly by activating hepatic autophagy.