Pioglitazone upregulates hepatic angiotensin converting enzyme 2 expression in rats with steatohepatitis.

OBJECTIVE: Angiotensin II, one component of renin-angiotensin system (RAS), is formed from Ang I by the catalysing of angiotensin converting enzyme (ACE). Angiotensin II plays an important role in the development of insulin resistance. ACE2, a homologue of ACE, couterregulate the actions of angiotensin II by facilitating its breakdown to angiotensin-(1-7). RAS has been implicated in the pathogenesis of non-alcoholic steatohepatitis (NASH). Earlier demonstration that thiazolidinediones (TZDs) improve steatohepatitis promoted us to evaluate the change of hepatic ACE2 expression in rats with high fat diet (HFD)-induced NASH and the effects of TZDs on the hepatic ACE2 expression. MATERIAL AND METHODS: Rats were divided into normal control group, high fat diet (HFD) group, and pioglitazone group. After 24 weeks of treatment with pioglitazone, a TZD, we evaluated changes in liver histology, insulin sensitivity, lipid metabolism, circulating RAS levels and hepatic ACE2 expression. RESULTS: Compared with normal controls, the concentrations of serum lipid, aminotransaminase, glucose, insulin, ACE, angiotensin II, ACE2, angiotensin-(1-7) and the degree of hepatic ACE2 expression were significantly higher in rats with HFD-induced NASH. Pioglitazone significantly reduced the concentrations of serum lipid, aminotransaminase, glucose, insulin, ACE, angiotensin II while markedly raised the concentrations of serum ACE2, angiotensin-(1-7) and the degree of hepatic ACE2 expression. CONCLUSION: Hepatic ACE2 expression markedly increased in rats with HFD-induced NASH and was further upregulated by pioglitazone. Hepatic ACE2 may be a new target of pioglitazone treatment for NASH.