Molecular and structural basis of portal hypertension.

Portal hypertension is a complication of diseases that obstruct portal blood flow, such as cirrhosis or portal vein thrombosis. In these diseases, increased vascular resistance to portal blood flow is the primary mechanism that increases portal pressure. In cirrhosis, increased intrahepatic vascular resistance is a result of both intrahepatic vasoconstriction and surrounding mechanical factors including collagen deposition and regenerative nodules. This article summarizes recent progress in the understanding of molecular mechanisms underlying the portal hypertension-associated arterial alterations in splanchnic systemic territories and those involved in the development of portal-systemic collateral circulation.