Serum type I collagen and N-terminal peptide of type III procollagen in chronic hepatitis: Relationship to liver histology and conventional liver tests

Abstract

The aim of this study was to compare serum N-terminal peptide of type III procollagen to aminotransferases and γ-globulins as a marker for histological activity in patients with chronic hepatitis and to assess the role of type I collagen, a new serum marker, as a marker of fibrosis in these patients. Sixty patients with biopsy-proven chronic hepatitis were included in this study. Liver disease was virus B-related in 29, autoimmune in five, drug-induced in five, and of unknown etiology in 21. Each biopsy was independently assessed by two liver pathologists. Two histological scores, a score of activity and a score of fibrosis, were established. Serum N-terminal peptide of type III procollagen and type I collagen were assayed by liquid phase RIA. Significant correlations were noted between serum N-terminal peptide of type III procollagen and scores of activity ( r = 0.70, p < 10 −4) and fibrosis ( r = 0.45, p < 0.0005), and between serum type I collagen and scores of activity ( r = 0.46, p = 0.0004) and fibrosis ( r = 0.67, p < 10 −4). When the correlation between scores of activity and fibrosis ( r = 0.52, p = 10 −4) was considered by partial correlation, serum N-terminal peptide of type III procollagen was correlated with the score of activity ( r = 0.63, p < 10 −4) but not with the score of fibrosis, and serum type I collagen was correlated with the score of fibrosis ( r = 0.58, p < 10 −3), but not with the score of activity. Correlations between the score of activity and serum alanine aminotransferase ( r = 0.50, p = 10 −4) and γ-globulins ( r = 0.37, p = 0.004) ware significant, but less than for serum N-terminal peptide of type III procollagen. In conclusion, our study demonstrated a correlation between serum N-terminal peptide of type III procollagen and histological activity independent of liver fibrosis in patients with chronic hepatitis. It suggested that in these patients, serum N-terminal peptide of type III procollagen might be a better marker of activity than serum alanine aminotransferase or γ-globulins. Moreover, serum type I collagen, a novel marker of collagen metabolism, was correlated with liver fibrosis. Serum markers of collagen metabolism may represent an alternative to liver biopsy for the assessment of activity and liver fibrosis in these patients, particularly during clinical trials.