Serum Mitochondrial Aspartate-Aminotransferase In Extrahepatic Cholestasis - Evolution After Bile-Duct Endoscopic Clearance

Aspartate aminotransferase (tAspAT) activity in the serum depends on two isozymes, mitochondrial (mAspAT) and cytosolic (cAspAT). We recently noted that the ratio of serum mitochondrial to total aspartate aminotransferase levels (mAspAT/tAspAT) is raised after biliary obstruction, and in alcoholic liver disease. The aim of this study was to establish whether these serum disturbances induced by biliary obstruction are reversible when the obstruction is relieved. A group of 186 patients with various liver diseases were studied. In patients with extrahepatic cholestasis, mAspAT serum concentration and mAspAT/tAspAT ratio were measured before and after endoscopic clearance. Levels of mAspAT were increased in 60% of the patients with extrahepatic liver cholestasis, in 91% with alcoholic liver disease and in 20% with non-alcoholic, non-cholestatic liver disease. The mAspAT/tAspAT ratio was 6 +/- 4, 8 +/- 4 and 2 +/- 1%, respectively, for each group. After endoscopic clearance in cholestatic patients, mAspAT and mAspAT/tAspAT normalized in < 48 h. This rapid decrease contrasted with a slower decrease recorded after alcohol intake was stopped. This observation is consistent with an immediately reversible hepatocyte injury of mechanical cause during extrahepatic cholestasis.