INS and fatty liver disease: In a human cohort study, PAA was found to be most strongly associated with hepatic steatosis and proved to induce the lipid accumulation in primary human hepatocytes by reducing the response to insulin via lowering AKT phosphorylation.46 Our results suggested that the increased bacterial production of SCFAs and PAA may contribute to the insulin resistance and liver lipid accumulation in the LKO mice, and their detailed effects and underlying mechanisms need to be further studied.