Mammalian collagenase increases in early alcoholic liver disease and decreases with cirrhosis

Abstract

To determine if alterations in collagen degradation may contribute to the pathogenesis of fibrosis and cirrhosis, we studied the hepatic collagenase activity of 20 baboons given alcohol containing diets or control diets under carefully controlled experimental conditions. We also studied 28 patients whose livers were biopsied for diagnostic purposes.

Hepatic collagenase activity was significantly increased in baboons with fatty liver compared to levels in normal, control fed animals [(1.98±0.19 vs 1.20±0.08 units (μg collagen digested/ hour/mg liver protein) ± S.E.M., p<0.001)]. The increase in hepatic collagenase activity persisted at the stage of fibrosis when compared to the activity in control baboons (2.16±0.07 vs 1.20±0.08 units ± S.E.M., p/s0.001). A single cirrhotic baboon available for study had an hepatic collagenase activity of 1.58 units.

Patients with hepatic fibrosis had significantly higher hepatic collagenase activity than those with fatty livers [(9.12±0.94 (n=14) vs 4.52±0.54 (n=7) units±S.E.M., p<0.001)]. However, in the group with cirrhosis, hepatic collagenase was lower [(3.92±0.61 (n=7) units ± E.S.M., p<0.001)] than in the group with fibrosis.

Our findings suggest that the development of cirrhosis is coincident with, or favored by a failure of hepatic collagen degradative enzymes to keep pace with hepatic collagen synthesis.