Backgrounds/aims: Serum retinol-binding protein 4 (RBP4) is known to be a specific transport protein for retinol, and has recently been reported to be associated with insulin resistance. Hyaluronic acid (HA) is a well-known marker of liver fibrosis. In this study, the degree to which serum RBP4 levels can be used to predict disease severity in patients with chronic liver disease (CLD) was evaluated.
Methods: Serum levels of RBP4 and HA were measured in 573 CLD patients [235 with chronic hepatitis (CH), 230 with liver cirrhosis Child-Pugh grade (Child) A, and 108 with liver cirrhosis with Child B and C] and 40 normal controls.
Results: The mean age of the whole cohort was 53.1 years and the causes of CLD were hepatitis B virus (61.9%), hepatitis C virus (9.8%), alcohol (9.0%), and nonalcoholic steatohepatitis (3.8%). Serum levels of RBP4 significantly reduced and HA increased with disease condition, from none (normal controls) to advanced cirrhosis (normal control: RBP4 4.3+/-0.1 mg/dL, HA 25.3+/-28.1 ng/mL; CH: RBP4 3.6+/-0.1 mg/dL, HA 75.5+/-7.8 ng/mL; cirrhosis with Child A: RBP4 2.6+/-0.1 mg/dL, HA 184.4+/-14.5 ng/mL; and cirrhosis with Child B and C: RBP4 1.6+/-0.1 mg/dL, HA 656.5+/-86.7 ng/mL; P<0.001, respectively). Serum RBP4 level was a distinguishing factor at the early stage of CLD between CH and Child A cirrhosis (post-hoc test; P<0.001) and was correlated with histological fibrosis score (n=80, P<0.05) and several biochemical factors. Antiviral therapy (n=45, median interval 1,205 days) resulted in an improvement in serum RBP4 levels (P=0.001).
Conclusions: The results of our study suggest that RBP4 is a serologic marker for disease severity in patients with CLD. It could also be useful as an early marker of CLD and of the relative success of antiviral therapy.