[The parameters of collagen proteolytic and metabolic systems in chronic liver diseases of viral and toxic etiologies].

AIM: To study a relationship of the plasma activity of elastase-like and collagenase-like proteinases and their inhibitors to hepatic collagen metabolism and to detect the serum markers of fibrosis severity.

SUBJECTS AND

METHODS

Three hundred and fifty-nine patients with chronic liver diseases (CLD), including 118 patients with chronic viral hepatitis (CVH), 113 with CVH concurrent with alcoholic liver disease (ALD), 109 with ALD, and 19 with CLD in the presence of opiomania were examined. The activities of alpha1-proteinase inhibitor and alpha2-macroglobulin (alpha2-MG) were determined by the unified spectrophometric assay from the inhibition of N-benzoyl-arginine ethyl ester hydrolysis. The activity of elastase-like proteinases was determined by enzymatic assay from the hydrolysis of the synthetic substrate N-butyloxycarbonyl-L-alanine-para-nitrophenyl ester. That of collagenase-like proteinases was determined, by using a collagen type 1 substrate and expressed in terms of micromoles of the resultant hydroxyproline. The content of hydroxyproline was determined by a color reaction with demethylbenzaldehyde, a free, peptide- and protein-bound hydroxyproline; their fraction was obtained under various conditions of plasma protein isolation and hydrolysis. Plasma fibronectin levels were measured by solid-phase immunoassay. Liver biopsy specimens were morphologically studied in the majority of patients to determine the histological hepatitis activity index and the stage of fibrosis.

RESULTS

Fibrois formation in the liver in its chronic diseases was attended by a significant reduction in the activity of collagenase-like proteinases hydrolyzing collagen and by the lower activity of alpha2-MG, an inhibitor limiting collagen formation.

CONCLUSION

The identified changes make themselves evident just in early fibrosis, which suggests the rapid onset of imbalance in the mechanisms responsible for regulation of connective tissue synthesis and promotes intensified fibrosis formation.