Importance of hepatitis C virus-associated insulin resistance:Therapeutic strategies for insulin sensitization

Insulin resistance is one of the pathological features in patients with hepatitis C virus(HCV) infection.Generally,persistence of insulin resistance leads to an increase in the risk of life-threatening complications such as cardiovascular diseases.However,these complications are not major causes of death in patients with HCV-associated insulin resistance.Indeed,insulin resistance plays a crucial role in the development of various complications and events associated with HCV infection.Mounting evidence indicates that HCV-associated insulin resistance may cause(1) hepatic steatosis;(2) resistance to anti-viral treatment;(3) hepatic f ibrosis and esophageal varices;(4) hepatocarcinogenesis and proliferation of hepatocellular carcinoma;and(5) extrahepatic manifestations.Thus,HCV-associated insulin resistance is a therapeutic target at any stage of HCV infection.Although the risk of insulin resistance in HCV-infected patients has been documented,therapeutic guidelines for preventing the distinctive complications of HCV-associated insulin resistance have not yet been established.In addition,mechanisms for the development of HCV-associated insulin resistance differ from lifestyle-associated insulin resistance.In order to ameliorate HCV-associated insulin resistance and its complications,the eff icacy of the following interventions is discussed:a late evening snack,coffee consumption,dietary iron restriction,phlebotomy,and zinc supplements.Little is known regarding the effect of anti-diabetic agents on HCV infection,however,a possible association between use of exogenous insulin or a sulfonylurea agent and the development of HCC has recently been reported.On the other hand,insulin-sensitizing agents are reported to improve sustained virologic response rates.In this review,we summarize distinctive complications of,and therapeutic strategies for,HCVassociated insulin resistance.Furthermore,we discuss supplementation with branched-chain amino acids as a unique insulin-sensitizing strategy for patients with HCVassociated insulin resistance.