High liver RBP4 protein content is associated with histological features in patients with genotype 1 chronic hepatitis C and with nonalcoholic steatohepatitis

Background and aim To investigate the hepatic expression of retinol-binding protein-4 (RBP4) in chronic hepatitis C (CHC) and nonalcoholic steatohepatitis (NASH) patients, and its association with biochemical and histological patterns of liver damage. Materials and methods Sixty-six genotype 1 CHC and 32 NASH patients were tested for hepatic RBP4 expression. Liver expression at immunostaining was scored as 0 (slight), 1 (mild), 2 (moderate), and 3 (intense). In addition, the mRNA and the quantitative protein expressions of RBP4 were tested by PCR and by western blot, respectively, in 12 NASH and 28 CHC patients. Twelve subjects undergoing elective cholecystectomy served as controls. Results Ten (31%), 16 (50%) and 6 (19%) NASH patients, and 21 (32%), 31 (47%) and 14 (21%) CHC patients had scores of 1, 2 and 3, respectively. All control subjects scored 0. In both CHC and NASH liver RBP4 scores were directly related to western blot ( p = 0.001 and p = 0.03), not to mRNA expression ( p = 0.77 and p = 0.40). Older age (OR, 1.07; 95%CI, 1.01–1.13), RBP4 score (4.26; 1.27–14.21) and HOMA (2.26; 1.15–4.42) were independently associated with steatosis ≥10% in CHC patients. In NASH lobular inflammation (OR, 3.77; 95%CI, 1.01–24.22) and RBP4 score (4.87; 1.003–23.65) were the only risk factors for fibrosis ≥2 at logistic regression analysis. Conclusion Hepatic storage of RBP4, unrelated to its expression, could cause liver damage both in NASH and CHC.