Connective tissue polypeptides in serum as parameters to monitor antifibrotic treatment in hepatic fibrogenesis.

With the potential to specifically inhibit hepatic collagen synthesis a demand for serum tests to monitor the effectiveness of such treatment is expected. Serum assays for connective tissue polypeptides offer the potential to assess the dynamics of accumulation, i.e., fibrogenesis, and removal, i.e., fibrolysis, of the hepatic connective tissue on a regular and frequent basis. Several assays for circulating connective tissue polypeptides may be of use in fibrogenic liver diseases. Whereas an increase of the aminoterminal propeptide of type III procollagen (PIIINP) appears to be related to fibrogenesis, the propeptides of type IV procollagen (PIVNP, PIVCP) and laminin mirror enhanced basement membrane turnover in active fibrosis. Collagen type VI (CVI) and undulin (Un) rather reflect fibrolysis and remodelling of the interstitial connective tissue. Although the circulating antigens measured by these assays are heterogeneous, which often complicates the interpretation of elevated serum levels, it is likely that firm conclusions can be drawn as to the ongoing fibrogenesis, fibrolysis or both, once individual patients are followed with a combined measurement of two or three of these connective tissue parameters. Since 'easy to perform' assays are currently developed, such as therapy control seems practicable.