Increased serum
urotensin II (UII) levels in human cirrhotic populations have been recently shown, but the long-term effects of UII receptor antagonist on the
cirrhosis have not been investigated. To investigate the
therapeutic effects of
urotensin II receptor (UT) antagonist
palosuran on rats with
carbon tetrachloride (CCl4)-induced
cirrhosis, the hepatic and systemic hemodynamics,
liver fibrosis, the metalloproteinase-13 (
MMP-13)/
tissue inhibitor of metalloproteinase-1 (TIMP-1) ratio, hepatic
Rho-kinase activity, and the
endothelial nitric oxide synthase (eNOS) activity are measured in CCl4-cirrhotic rats treated with
palosuran or vehicle for 4 weeks. Primary hepatic stellate cells (HSCs) are used to investigate the changes in UII/UT expression and the in vitro effect of
palosuran. Compared with the vehicle-treated cirrhotic rats, treatment with
palosuran can reduce the portal pressure (PP), decrease the risk of
liver fibrosis and the level of α smooth muscle actin,
collagen-I (COL-I), and
transforming growth factor β expression. However, treatment with
palosuran can increase
MMP-13/TIMP-1, pvasodilator-stimulated
phosphoprotein (p-VASP), and p-eNOS expression. Moreover, in vitro UII/UT
mRNA expression increases during HSC activation.
MMP-13/TIMP-1, COL-I, and p-VASP are inhibited after
palosuran treatment. Our data indicate that long-term administration of
palosuran can decrease PP in
cirrhosis, which results from decreased hepatic
fibrosis and enhanced eNOS-dependent HSC vasodilatation.