THE ROLE OF ESTROGEN AND EFFECT OF ANTI-ESTROGEN THERAPY ON EXPERIMENTAL HEPATOPULMONARY SYNDROME

Abstract

Background: Hepatopulmonary syndrome consists of a triad of liver dysfunction, intrapulmonary vascular dilatation, and hypoxemia. The loss of vascular tone in patients with intrapulmonary vascular dilatation is unexplained. Many studies in liver cirrhosis and pregnancy revealed that the cause of cutaneous vascular dilatation (spider nevi) is estrogen.

Aim: We tried to explain the effects of estrogen in intrapulmonary vascular dilatation.

Material-Methods: We used an animal model for the study of hepatopulmonary syndrome by ligating the common bile duct in rats and inducing biliary cirrhosis over 5 week period. Six groups each consist ten rats (1 :Sham-control, 2: Common bile duct ligation, 3: Common bile duct ligation and oophorectomy, 4: Common bile duct ligation and exogenous estrogen, 5:Common bile duct ligation and tamoxifen, 6: Exogenous estrogen groups) were studied. Arterial blood gases, hepatic biochemical and histological features, and oculometric measurements of intrapulmonary vascular dilatation were assessed.

Results: In common bile duct ligated rats we obtained biliary cirrhosis, hypoxemia and intrapulmonary vascular dilatation. Compared with only common bile duct ligated group, degree of hypoxemia and intropulmonary vasculary dilatation were more evident in cirrhosis plus exogenous estrogen administrated group however those were less in cirrhosis plus tamoxifen and cirrhosis plus oophorectomy groups.

Conclusion: We consider that estrogen has a potential role in intrapulrnonary vasculary dilatation and hypoxemia in hepatopulmonary syndrome and anti-estrogen therapy may prevent the development of intrapulmonary vascular dilatation in cirrhosis.