An interesting theory would be that, in patients with liver cirrhosis, BNP is elevated partly as a compensatory reaction to liver injury since BNP hyperexpression in mice protects against liver fibrosis, and BNP in rats with liver cirrhosis had a significant effect on reducing the pressure in the portal vein despite a weaker natriuretic effect compared with healthy rats (83,86). Here, NPPB is linked to cirrhosis of liver.