In contrast, during hepatic arterial ligation-induced ischemia of the biliary system, the PVP collapses, and the biliary epithelia show increased apoptosis and decreased VEGF secretion [3,17], suggesting a close link between biliary epithelial proliferation and secretion of VEGF from biliary epithelial cells and proliferation of PVP. This evidence concerns the gene VEGFA and ischemia.