[Research advances of sarcopenia in chronic liver disease]

Sarcopenia is the main constituent of malnutrition and is a frequent complication of chronic liver diseases, which affects up to 70% of patients with advanced liver diseases. It has been associated with adverse clinical outcomes and prognosis, including poor quality of life, development of other complications and reduction in survival rate of non-transplant patients and transplant recipients. Chronic liver disease causes alteration in glucose metabolism, lipid oxidation, ketogenesis and protein catabolism, leading to the loss of adipose and muscle tissue. In addition, inadequate nutrients intake and limited or lack of physical activity perpetuate the reduction of muscle mass. Recently, the roles and mechanisms of muscle growth-related hormones, hyperammonemia-mediated signaling pathways and gut microbiota have been recognized. In view of its impact in chronic liver disease, sarcopenia can be considered as a powerful prognostic factor and a useful additional tool in the global assessment of patients with advanced liver disease. Rational nutritional intervention, appropriate physical exercise, effective ammonia lowering strategies, hormone supplements and targeted molecular therapy (use of myostatin blockers), and liver transplantation, may improve sarcopenia, but still needs more studies for validation.