Hepatic sonic hedgehog protein expression measured by computer assisted morphometry significantly correlates with features of non-alcoholic steatohepatitis

Abstract

BackgroundHepatic expression of Sonic Hedgehog (SHH) is associated with Non-alcoholic fatty liver disease (NAFLD) and development of Non-alcoholic steatohepatitis (NASH). Hepatic SHH detection increases with the diagnosis of NASH. This pilot study was designed to confirm that staining for SHH is useful in NASH diagnosis and determine whether quantification of staining by computer assisted morphometry (CAM) can be used to assess severity of ballooning degeneration.MethodsSHH was detected by immunohistochemistry (IHC) on paraffin-embedded liver sections in subjects (N = 69) with biopsy proven NAFLD and no liver disease (control). Serum samples were also available for these subjects. Post-staining, a digitized image of the section was acquired and an area quantification algorithm was used to quantify the degree of SHH expression. Additionally, circulating M30, M65, and SHH were measured by ELISA.ResultsNotably, hepatic SHH expression correlated with histologic ballooning degeneration (rho = 0.62, p < 0.0001), steatosis grade (rho = 0.554, P < 0.001), Mallory-Denk bodies (rho = 0.54, P < 0.001), pericellular fibrosis (rho = 0.527, P < 0.001), and lymphocytic infiltration (rho = 0.435, P < 0.0002). Additionally, hepatic SHH expression correlated with circulating M65 (rho = 0.588, p < 0.0001), and circulating M30 (rho = 0.375, p = 0.001), as well as AST and ALT (rho = 0.43, p = 0.0004, and rho = 0.27, p = 0.03, respectively). Further, serum M30 was almost twice as high in NASH patients compared to non-NASH (539.1 ± 290.8 U/L vs. 287.6 ± 190.5 U/L; p = 0.0002), while M65 was almost three times higher in NASH patients compared to non-NASH (441.2 ± 464.2 U/L vs. 162.8 ± 353.1 U/L, P = 0.0006). Logistic modeling indicates hepatic SHH expression and presence of type 2 diabetes as independent predictors of advanced fibrosis (defined as portal and pericellular fibrosis > 2: OR = 1.986, p = 0.01, and OR = 3.280, p = 0.03, respectively).ConclusionThus, our findings show quantitation of SHH expression by CAM can provide a tool for quantifying changes in hepatocyte injury and assist in unambiguous staging/grading of NASH. Our study showed minimal interobserver variability using CAM based quantification. Once validated, CAM assessment of hepatic SHH could benefit clinical trials or long term outcomes studies of NASH subjects.