Background & aims: Although in cirrhosis with portal hypertension levels of the vasoconstrictor angiotensin II are increased, this is accompanied by increased production of angiotensin (Ang)-(1-7), the endogenous ligand of the Mas receptor (MasR), which blunts hepatic fibrosis and decreases hepatic vascular resistance. Therefore, we investigated the effects of the non-peptidic Ang-(1-7) agonist, AVE0991, in experimental cirrhosis.
Methods: Cirrhosis was induced by bile duct ligation (BDL) or carbon tetrachloride (CCl4) intoxication. The coloured microsphere technique assessed portal and systemic hemodynamic effects of AVE0991 in vivo. Hepatic expression of eNOS, p-eNOS, iNOS, JAK2, ROCK and p-Moesin were analyzed by western blots. Activities of ACE and ACE2 were investigated fluorometrically. Moreover, fibrosis was assessed in BDL rats receiving AVE0991.
Results: In vivo, AVE0991 decreased portal pressure (PP) in both rat models of cirrhosis. Importantly, systemic effects were not observed. The hepatic effects of AVE0991 were based on upregulation of vasodilating pathways involving p-eNOS and iNOS, as well as by downregulation of the vasoconstrictive pathways (ROCK, p-Moesin). Short-term treatment with AVE0991 decreased the activity of ACE2, long-term treatment did not affect hepatic fibrosis in BDL rats.
Conclusions: The non-peptidic agonist of Ang-(1-7), AVE0991, decreases portal pressure without influencing systemic pressure. Thus, although it does not inhibit fibrosis, AVE0991 may represent a promising new therapeutic strategy for lowering portal pressure.