The Level of Connective Tissue Growth Factor in Sera of Patients with Hepatitis B Virus Strongly Correlates with Stage of Hepatic Fibrosis

Abstract

Connective tissue growth factor (CTGF) plays a crucial role in the formation and development of hepatic fibrosis. The aim of this study was to establish a method for CTGF determination in order to investigate the level of CTGF in the sera of patients with hepatitis B virus, and to assess the correlation between CTGF concentration and stage of hepatic fibrosis. A CTGF C-terminal region gene was obtained by RT-PCR of human mesangial kidney cells and inserted into pET-32a((+)) vector. Recombinant protein was obtained by expression and purification of the fused protein. Polyclonal and monoclonal antibodies were prepared to establish a sandwich ELISA method. CTGF levels in 18 healthy serum samples and 83 serum samples from patients with hepatitis B virus were assessed. A simple, sensitive, and noninvasive method of determining CTGF levels was successfully established. CTGF levels in the sera of patients with hepatitis B were significantly increased compared controls (p < 0.001). There was a strong correlation between CTGF concentration and fibrotic stage (r = 0.8906, p < 0.005). No significant association was found between CTGF level and the grade of hepatic inflammation (p > 0.05). The area under the receiver operating characteristic (ROC) curves of CTGF was 0.681 for identification of significant fibrosis, and 0.759 for the diagnosis of middle- and late-stage fibrosis. Accuracy of CTGF assessment was independent of age, renal function, liver function, platelet count, or other biochemical markers of liver fibrosis (all p > 0.05). No significant correlation was found between CTGF and several humoral factors associated with liver fibrosis (all p > 0.05). The levels of CTGF in the sera of patients with hepatitis B were strongly associated with the stages of hepatic fibrosis, and CTGF may become a useful diagnostic aid in assessing hepatic fibrosis.