Bile duct matrix metalloproteinase-7 expression: a new modality for diagnosis of biliary atresia

Biliary atresia (BA) is an obliterative cholangiopathy of infancy that results in cholestasis and liver fibrosis. This fibrosis is due to an imbalance in extracellular matrix (ECM) breakdown and deposition. The mechanism by which the progressive injury occurs is not fully elucidated. Matrix metalloproteinases (MMPs) are involved in ECM turnover but also have non-ECM-related functions. Matrix metalloproteinase 7 (MMP7) has been suggested as a promising biomarker in diagnosing BA.

The aim of this study was to assess the hepatic expression of MMP-7 in infants with BA.

The study was a retrospective-prospective case–control study that included 50 patients who were categorized into two groups, BA group (25 patients) and non-BA cholestatic patients as a control group (25 patients). Liver biochemistry, liver biopsy, histopathology, and immunohistochemical staining for primary antibody MMP-7 were performed for all studied patients.

Bile duct MMP7 expression was significantly higher in infants with BA than in non-BA cholestasis (P = 0.003), While the hepatic MMP-7 intensity did not differ significantly between both groups (P > 0.05). Bile duct expression of MMP-7 had a significant positive correlation with the BA Score (P = 0.017), while hepatic MMP-7 intensity had a significant positive correlation with alanine transaminase levels (P = 0.007) and a significant negative correlation with γ glutamyl transferase in the BA group (P = 0. 038). There was no statistically significant difference among different stages of fibrosis as regards the median of the hepatic MMP-7 intensity score and MMP-7 bile duct expression in infants with BA. There was no statistically significant difference between infants with successful and failed Kasai as regard the hepatic MMP-7 intensity and its bile duct expression.

Bile duct expression of MMP-7 measured by immunohistochemistry is useful for the diagnosis of BA, but it is limited in predicting the stage of liver fibrosis and the outcome of Kasai portoenterostomy (KPE).