Fecal Microbiota Transplantation for Treating Hepatic Encephalopathy: Experimental and Clinical Evidence and Possible Underlying Mechanisms

Gut microbiota changes play a key role in the pathogenesis of hepatic encephalopathy (HE). Fecal microbiota transplantation (FMT) is an efficient way to manipulate the gut microbiota. This review collects the experimental and clinical evidence that supports the use of FMT in the treatment of HE. Animal experiments showed that the blood ammonia level, mortality and cognitive impairment were decreased when animals with HE were transplanted with the selected gut microbiota or the fecal material from human donor. Successful clinical application of FMT for treating HE was first reported in 2016. A subsequent randomized clinical trial demonstrated further that FMT from a “rationally selected donor” reduced hospitalizations and improved cognition and dysbiosis in patients with recurrent HE. Possible underlying mechanisms of FMT treating HE include restoration of the impaired gut-liver-brain axis, as well as reduction of ammonia production, systemic inflammation and blood-brain barrier permeability.