Angiopoietin 1 and angiopoietin 2 are associated with medial thickening of hepatic arterial branches in biliary atresia.

BACKGROUND: Biliary atresia (BA) is an infantile disorder characterized by progressive sclerosing cholangiopathy leading to biliary obstruction. First-line treatment of BA is hepatoportoenterostomy, the prognosis of which is related to age at surgery and to histological variables such as extent of fibrosis and ductular reaction. Hepatic arterial medial thickening (MT) suggests an arteriopathy in BA pathogenesis. We evaluated the expression of angiopoietin (ANGPT)/tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 2 (TIE2) system in liver samples obtained from patients with BA, correlating it with MT, variables associated with disease severity, and postoperative prognosis. METHODS: ANGPT1, ANGPT2, and TIE2 expression levels were assessed by quantitative PCR in liver samples obtained from BA patients (n = 23) at portoenterostomy and age-matched infants with intrahepatic cholestasis (IHC; n = 7). Histological variables were morphometrically assessed. RESULTS: ANGPT1 and ANGPT2 were overexpressed in BA in comparison with IHC (P = 0.024 and P = 0.029, respectively). In BA, ANGPTs expression was positively correlated with MT (ANGPT1: rs = 0.59, P = 0.013; ANGPT2: rs = 0.52, P = 0.032), not with the variables associated with disease severity. TIE2 and ANGPTs expression levels were negatively correlated (ANGPT1: rs = -0.73, P < 0.001; ANGPT2: rs = -0.54, P = 0.007). CONCLUSION: In BA, there is overexpression of both ANGPT1 and ANGPT2, which is correlated with MT but not with age at portoenterostomy or with the histological variables associated with disease severity at the time of procedure.