Lipocytes and transitional cells in alcoholic liver disease: A morphometric study

Abstract

Lipocytes and transitional cells in alcoholic liver disease were analyzed by quantitative morphometry in liver biopsy specimens of 17 alcoholic patients. In fatty livers, 93% of the perisinusoidal cells were lipocytes with a volume of lipid droplets occupying more than 20% of the individual cell volume. In fatty livers with perivenular fibrosis, 83% of the cells were lipocytes and 17% were transitional cells with lipid droplets of less than 20% of the cell volume. In cirrhosis, 45% of the cells were lipocytes and 55% of the cells were transitional cells. Thus, the process of hepatic fibrosis was associated with a shift from lipocytes to transitional cells. The percentage of transitional cells (expressed as total perisinusoidal cells) was 5.1% in fatty livers, 16.5% in fatty livers with perivenular fibrosis (not significantly different when compared to fatty livers) and 59.7% in cirrhotic livers (p < 0.025) when compared to fatty livers or fatty livers with perivenular fibrosis). The number of transitional cells per 100 hepatocytes was estimated to be 0.5 in fatty livers, 1.3 in fatty livers with perivenular fibrosis and 2.1 in cirrhotic livers. The appearance of transitional cells was associated with a corresponding decrease in the number of lipocytes, supporting the hypothesis that transitional cells were derived from lipocytes. In comparison to lipocytes, the surface area of transitional cells (as measured by digitized morphometry) was 30 to 46% smaller (p < 0.01). When expressed as the percentage of the total cell area, the lipid droplet compartment in transitional cells was 34% smaller (p < 0.001) than that in lipocytes, whereas the nonlipid cytoplasmic and nuclear compartments in transitional cells were 18 to 20% (p < 0.01) and 15% (p < 0.05) larger than those in lipocytes, respectively. The rough endoplasmic reticulum in transitional cells became better developed than that in lipocytes, but only at the cirrhotic stage, confirmed by quantitative morphometry. We found a significantly higher collagen score in the Disse space surrounding transitional cells in fatty livers with perivenular fibrosis or cirrhosis compared to that of lipocytes. In two cases of alcoholic hepatitis with cirrhosis, virtually all perisinusoidal cells exhibited structural features and morphometric values comparable to those of transitional cells in the livers without hepatitis. In the liver of one nonalcoholic subject, perisinusoidal cells exhibited structural features and morphometric values comparable to those of lipocytes in the livers of alcoholics.