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

Abstract

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 ultra- sound 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 hydro- gen on intracellular lipid accumulation. Collectively, hydrogen/oxygen inhalation al- leviated NAFLD in moderate–severe patients. This protective effect of hydrogen was possibly by activating hepatic autophagy.

Study details

Article type

Original Research

Disease / injury model

Non-alcoholic fatty liver disease (NAFLD), MCD diet-induced NASH (animal), FFA/PA-induced steatosis (cell)

Duration

13 weeks

Dose-dependent effect

No

Outcome

Positive

Findings

Hydrogen/oxygen inhalation for 13 weeks improved serum lipid and liver enzymes, and significantly improved liver fat content in moderate–severe NAFLD patients. Animal and in vitro studies supported the beneficial effect, showing reduced inflammation, improved liver histology, and promoted autophagy. The protective effect is possibly mediated by activating hepatic autophagy.