Purpose of Review
In non-alcoholic fatty liver disease (NAFLD), an increased portal pressure is observed before signs of cirrhosis or even inflammation or fibrosis are histologically present. This review describes the differences between the mechanisms of cirrhotic portal hypertension (PHT) and PHT in non-cirrhotic NAFLD.
Recent Findings
The increased portal pressure in NAFLD is primarily a result of an increased intrahepatic vascular resistance. Vasodilation is decreased by endothelial dysfunction and the sensitivity to vasoconstrictors is increased. Furthermore, the activation of hepatic stellate cells and the presence of microvascular thrombosis could also be involved in the pathogenesis of PHT in NAFLD.
Summary
Although the increased portal pressure in early NAFLD is not considered clinically significant PHT, it might play a role in the pathophysiology of NAFLD. Due to the increased intrahepatic vascular resistance, the hepatic blood flow is impaired and hence the oxygen delivery is decreased, potentially triggering transition to steatohepatitis. The underlying mechanisms of these alterations therefore represent promising targets for pharmacological treatment.