Alcoholic liver disease is characterized by the accumulation of fat and inflammatory changes in the liver. Because free fatty acids, the precursors of triglycerides, can damage biological membranes, accumulation of free fatty acids in the liver might be in part responsible for the functional and morphological changes seen in alcoholic liver disease. We, therefore, determined the hepatic lipid composition in biopsies from 31 patients with alcoholic liver disease, 18 patients with morbid obesity, and 5 patients without evidence of liver disease. Free fatty acids were found in all liver biopsies. Patients with morbid obesity or alcoholic liver disease had significantly higher fatty acid and triglyceride levels than did controls (p < 0.01). Patients with alcoholic liver disease had significantly higher fatty acid levels than did patients with morbid obesity (p < 0.05), while there was no difference in the triglyceride concentrations between these two groups. The distribution of the fatty acids in the free fatty acid fraction differed significantly from that in the triglyceride fraction indicating a preferential incorporation of unsaturated fatty acids into triglycerides. This difference in the distribution pattern was lost in patients with the most severe forms of alcoholic liver disease. The data are consistent with the hypothesis that accumulation of free fatty acids in patients with alcoholic liver disease may be responsible for or contribute to the observed functional and morphological damages.
Hepatic accumulation of fat is frequently associated with impairment of liver function tests and morphologic evidence of liver cell injury and inflammation (1). Most commonly, this association is found in alcoholic liver disease (ALD) (1, a), but liver cell injury in association with hepatic steatosis can be observed in diabetes mellitus (1,3), obesity before or after intestinal bypass surgery (1, 4, 5), Reye's syndrome (6), during parenteral hyperalimentation (7), and in the fatty liver of pregnancy (8). The predominant hepatic lipids in these conditions are triglycerides. Fatty acids, the precursors of triglycerides, have only on rare occasions been quantitatively determined in liver tissue (6, 4 9 ) . Since fatty acids can cause tissue injury (10-12), it is possible that significant accumulation of fatty acids in the liver might contribute to the observed hepatocyte injury. We therefore studied