Serum and tissue transforming [corrected] growth factor β1 in children with biliary atresia

Biliary atresia (BA) is an infantile disorder characterized by the obstruction of a portion or the entirety of the extrahepatic bile ducts, leading to hepatic fibrosis and loss of liver function. The gold standard for diagnosing and grading fibrosis is liver biopsy, but there are many groups searching for noninvasive biomarkers that could replace and/or complement this procedure.

In this study, we evaluated serum and tissue transforming growth factor β1 (TGFβ1) and aspartate aminotransferase [AST]-to-platelet ratio index (APRI) in patients with BA at the time of diagnosis and at liver transplantation and correlated these data with tissue collagen density, to verify if they could act as biomarkers for BA.

At the time of diagnosis, TGFβ1 levels were highly variable in BA patients. However, serum values at transplantation were significantly decreased (13.75 ± 3.68 ng/mL) as compared to controls (34.36 ± 9.35 ng/mL) (P = .01). No correlation was found between serum TGF1β1 and collagen density in both groups analyzed. Serum TGFβ1 showed no correlation with APRI at diagnosis. At the time of liver transplantation, all patients had low serum TGFβ1 and variable APRI, although all higher than 2.0. However, when platelet count was used, an inverse correlation with serum TGFβ1 was observed at the time of diagnostics (r(2) = 0.749; P = .03).

Our findings suggest that at the time of diagnosis the fibrogenic process is active, with higher levels of TGFβ1, whereas later on, there is scar tissue, with reduced TGFβ1 expression. Although our results should be confirmed in larger sets of patients with BA, the lack of TGFβ1 at the time of liver transplantation may have important consequences for the patient because it is a pleiotropic molecule, responsible for many functions in the body, mainly those related to immune response and cell growth.