Non-alcoholic steatohepatitis caused by oral bacteria

Background: Liver damage caused by excessive nutrient intake without a history of alcohol consumption is collectively referred to as nonalcoholic fatty liver disease, while progressive inflammatory changes and fibrosis of the liver are defined as non-alcoholic steatohepatitis (NASH). Recently, the mechanisms by which oral bacteria are involved in systemic diseases have been uncovered, though few reports of their association with fatty liver have been reported. Objective: This review aimed to summarize relevant current knowledge related to the detailed mechanisms of oral bacteria-associated NASH development. Main results: Recent reports have noted detection of highly pathogenic oral bacteria in NASH patients. In addition, NASH-like symptoms have been reported following administration of oral bacteria in a mouse model of obesity induced by a high-fat diet. Conclusions: These results reveal important details regarding the mechanism of NASH development by oral bacterial infection.