Serum concentrations of the carboxyterminal cross-linking domain of procollagen type IV (NC1) and the aminoterminal propeptide of procollagen type III (PIIIP) in chronic liver disease

Serum concentrations of both the carboxyterminal cross-linking domain (NC1) of procollagen type IV and the aminoterminal propeptide of procollagen type III (PIIIP) were measured by specific radioimmunoassays in 60 patients with chronic liver disease and 50 healthy controls. Compared with controls (5.3 +/- 1.3 ng/ml, mean +/- S.D.), NC1 concentrations were significantly elevated in patients with chronic active hepatitis (10.2 +/- 2.0 ng/ml) and liver cirrhosis (13.5 +/- 3.0 ng/ml), but not in chronic persistent hepatitis (6.0 +/- 0.9 ng/ml). The concentrations in patients with active liver cirrhosis were significantly higher than those in patients with inactive cirrhosis. Serum concentrations of PIIIP in controls, parients with chronic persistent hepatitis, chronic active hepatitis and cirrhosis were 5.8 (4.3-7.9), 5.3 (3.5-7.9), 17.5 (10.6-28.9), 16.7 (10.4-26.7) ng/ml, respectively (logarithmic mean and range of mean +/- S.D. after retransformation). Patients with liver cirrhosis had significantly higher concentrations of NC1 in serum than those with chronic active hepatitis, but there was no difference in serum PIIIP concentrations between the two groups. These data suggest an alteration of type IV collagen metabolism in chronic liver disease. In liver cirrhosis, the metabolism of collagen IV is apparently different from that of collagen type III; serum NC1 determinations may therefore provide additional information on chronic liver disease, particularly in patients with cirrhosis with a normal level of serum PIIIP. Further follow-up studies as well as investigations related to the basic mechanism of the elevation of these peptides in serum are needed in order to understand their clinical significance fully.