Abnormality in membrane fatty acid compositions of cells measured on erythrocyte in alcoholic liver disease.

It has been proven that the fatty acids of esterified phospholipids in the cell membrane play an important role in membrane fluidity. Our previous in vitro experiment indicated that the impairment of erythrocyte membrane fluidity might be largely because of the change in fatty acids. The aim of this study is to clarify changes of cell membrane fatty acids in more detail in relation to various stages and pathology of alcoholic liver disease. For the analysis, erythrocyte membranes were exploited on the assumption that their fatty acid compositions may be similar to those of other organs. In alcoholic liver disease, unsaturated fatty acids in the erythrocyte membrane decreased and saturated fatty acids increased. Consequently, the unsaturated fatty acid/saturated fatty acid ratio decreased significantly. When fractions of saturated fatty acids were studied, myristic acid (C14:0) increased markedly in the alcoholic group, and the increase was striking particularly in the cases of alcoholic hepatitis concurrently with hemolysis. Palmitic acid (C16:0) also tended to increase in the alcoholic liver disease group. A longer chain saturated fatty acid, stearic acid (C18:0), showed a moderate but significant increase in the alcoholic fatty liver and hepatic fibrosis group, but it decreased significantly in the alcoholic liver cirrhosis, as with the finding in viral liver cirrhosis. As with unsaturated fatty acids, linoleic acid (C18:2), arachidonic acid (C20:4), and eicosapentanoic acid (C20:5) decreased significantly. The arachidonic acid/linoleic acid ratio, which indicates microsomal elongation activity of liver cells, was found to be broadly distributed. No significant change was found in each group of alcoholic liver disease. However, the cases showing a decrease in this ratio had severe hepatic dysfunction concurrently. Thrombogenic Index, serving as an indicator for fatty acids in food, and that is concerned with formation of thrombus, was studied, using fatty acid fractions of the erythrocyte membrane. The index was significantly increased in alcoholic liver disease. It was suggested that the chronic alcohol intake and the resultant liver diseases might enhance the abnormality of the membrane fatty acid composition. These changes may affect cell membrane fluidity and eventually metabolic functions of the cell.