Low-dose valine attenuates diet-induced metabolic dysfunction-associated steatotic liver disease (MASLD) in mice by enhancing leptin sensitivity and modulating the gut microbiome.

Elevated circulating branched-chain amino acids (BCAAs) have been associated with obesity, insulin resistance, and MASLD, yet BCAA supplementation has been shown to provide protective outcomes towards the intervention of MASLD. Currently, there is a lack of study towards the contribution of the BCAA: valine on MASLD. This study investigates the effects of low-dose valine supplementation on MASLD in a high-fat/high-cholesterol diet (HFD) model. Low-dose valine was found to attenuate the progression of MASLD, significantly reducing body weight, liver weight, and eWAT weight, attenuating hyperglycemia and improving serum lipid profiles. It also decreased hyperleptinemia and enhanced hypothalamic leptin sensitivity, leading to reduced food intake. In the eWAT, metabolic flexibility was improved, as indicated by upregulated adipogenesis-related gene expressions and suppressed leptin expression. In the liver, valine improved hepatic leptin sensitivity, alleviated hepatic steatosis, and reduced triglycerides, cholesterol, TNFα, and IL-6 levels. Mechanistically, valine increased hepatic antioxidant capacity and modulated lipid metabolism and antioxidant pathways, downregulating de novo lipogenesis and cholesterol synthesis while increasing fatty acid oxidation, autophagy-related gene expressions. Moreover, hepatic AMPK pathway activity was enhanced, contributing to improved leptin sensitivity and signalling. Additionally, low-dose valine supplementation also modulated the gut microbiome, suggesting a multifaceted approach to managing MASLD.