Metabolic complications of hepatitis C virus infection

Abstract

Hepatitis C virus (HCV) infection is a systemic disease that is implicated in multiple extrahepatic organ dysfunction contributing to its protean manifestations. HCV is associated with diverse extrahepatic disorders including atherosclerosis, glucose and lipid metabolic disturbances, alterations in the iron metabolic pathways, and lymphoproliferative diseases over and above the traditional liver manifestations of cirrhosis and hepatocellular carcinoma. The orchestration between HCV major proteins and the liver-muscle-adipose axis, poses a major burden on the global health of human body organs, if not adequately addressed. The close and inseparable associations between chronic HCV infection, metabolic disease, and cardiovascular disorders are specifically important considering the increasing prevalence of obesity and metabolic syndrome, and their economic burden to patients, the healthcare systems, and society. Cellular and molecular mechanisms governing the interplay of these organs and tissues in health and disease are therefore of significant interest. The coexistence of metabolic disorders and chronic hepatitis C infection also enhances the progression to liver fibrosis and hepatocellular carcinoma. The presence of metabolic disorders is believed to influence the chronicity and virulence of HCV leading to liver disease progression. This comprehensive review highlights current knowledge on the metabolic manifestations of hepatitis C and the potential pathways in which these metabolic changes can influence the natural history of the disease.

Keywords: Chronic hepatitis C infection; Insulin resistance; Metabolic syndrome; Cardiovascular diseases; Fatty liver; Diabetes mellitus

Core Tip: Available evidence proves a strong association between hepatitis C virus (HCV) and metabolic complications such as hyperlipidemia, hepatic steatosis, insulin resistance, metabolic syndrome, and diabetes mellitus. De novo development of insulin resistance and hepatic steatosis in chronic HCV infection influences the disease progression in the liver and enhances overall morbidity and mortality. The influence of metabolic diseases on HCV infection can increase disease severity. The interplay between HCV major proteins and the liver-muscle-adipose axis is complex and still not fully elucidated. Coexistence of metabolic diseases such as diabetes mellitus and HCV infection are also known to result in adverse outcomes of both disorders. There is evidence that successful treatment halts the progression of liver disease, but more studies are required on how treatment influences the metabolic manifestations.