Evaluation of Hepatic Expression of VEGF and α-SMA in normal dogs and dogs with Congenital Portosystemic Shunt.

Abstract

In dogs with congenital portosystemic shunts (CPSS) portal venous blood is diverted around the liver and occlusion of the anomalous vessel is the treatment of choice. Patients that do not respond well to surgery after complete closure of the shunt may show portal hypertension, acute shock, death or evidence of continued hepatic dysfunction. Hepatic proliferation and development of the portal vein and its branches are probably important for recovery of patients after shunt closure. Certain factors, like VEGF and α-SMA, may play a significant role in these processes. Therefore livers of normal dogs and dogs with CPSS were investigated immunohistochemically for VEGF and α-SMA expression. Liver tissue of dogs with CPSS had increased VEGF and α-SMA expression. It seemed that only in patients that did not fully recover, VEGF expression was elevated. In the portal tracts of affected liver tissue also proliferation of hepatic arteries and less normal sized portal veins were present. An elevated level of VEGF might result from aberrant function or distribution of VEGF-receptors. The results of this study are promising for more extensive research of expression of VEGF and VEGF-receptors in dogs with CPSS.