Hepatic Expression of Fibroblast Growth Factor 19 Significantly Correlates With Serum Bile Acids in Neonatal Cholestasis.

Background: Bile acids in the ileum act as a feedback regulator of their own synthesis by inducing the release of ileal fibroblast growth factor 19 (FGF19), which inhibits the cholesterol-7-alpha hydroxylase enzyme. In cholestasis, this feedback mechanism is dysregulated. FGF19 is not expressed in the healthy liver. We aimed to assess the hepatic expression of FGF19 in neonatal cholestasis (NC) and its relation to serum bile acids.

Methods: The study included 41 patients with NC. FGF19 immunohistochemical staining in liver tissue (hepatocytes, endothelial cells, bile ducts, and bile canaliculi) was evaluated as negative, weak, moderate, and strong staining. FGF19 staining in 6 liver samples from explants of children with Crigler-Najjar syndrome type-1 served as controls.

Results: Hepatocyte, endothelial, and canalicular FGF19 expression was significantly higher in cholestasis group compared to controls (P = .039, .006, and .028 respectively). Serum bile acids had significant correlation with hepatocyte FGF19, endothelial, and bile duct FGF19 expressions (P = .002, .003, and .01, respectively) but not with canalicular FGF19 expression. Hepatocyte FGF19 expression significantly associated with cholestasis severity in terms of serum total bilirubin, direct bilirubin, and aspartate transaminase levels (P = .01, .02, and .02, respectively).

Conclusion: Hepatic FGF19 expression significantly upregulated in NC and correlated with cholestasis severity.