MORPHOLOGICAL ADAPTATIONS OF HUMAN LIVER PEROXISOMES IN CHOLESTASIS

Part of the bile acid synthesis takes place in peroxisomes. An altered enterohepatic circulation of bile acids might influence peroxisomal b eta-oxidation enzymes and peroxisomal morphology. We performed a morph ological and morphometric investigation of peroxisomes in liver biopsy samples of eight patients with cholestasis of different origin: graft versus host reaction (n=1), obstruction of the bile flow (n=3), and d rug-induced cholestatic hepatitis (n=4). Peroxisomes were identified u sing catalase cytochemistry. They were regularly shaped and showed ind ividual differences in electron density. A perinuclear distribution wa s observed in a variable number of hepatocytes in each sample. Morphom etric analysis of peroxisomes revealed an increase in numerical densit y and surface density in all, and a decreased mean diameter in four li ver samples. Based on previously obtained data in experimental animals , we hypothesize that the observed alterations in peroxisomal morpholo gy indicate an enhanced metabolic activity of the enzymes in the perox isomal matrix. Among them are enzymes involved in bile acid synthesis.