Low Km ALDH isozyme and alcoholic liver injury.

To assess the relationship between the polymorphism of aldehyde dehydrogenase (ALDH) isozyme and alcoholic liver injury, ALDH isozyme was analyzed by isoelectric focusing electrophoresis in hair roots from normal volunteers and alcoholics with chronic liver disease. Liver biopsy specimens from alcoholics and non-alcoholics with chronic liver disease were also analyzed. It was found that (1) the frequency of low Km ALDH isozyme in hair roots from chronic alcoholics with liver injury was 90%, which was significantly higher than those from normal volunteers (44%) and from non-alcoholics with chronic liver disease (56%); (2) the isozyme pattern of liver specimens analyzed coincided with that of hair roots; (3) the low Km ALDH isozyme-positive subjects including alcoholics showed no facial flushing, and negative subjects showed facial flushing after drinking alcohol. It is concluded that a much higher frequency of low Km ALDH isozyme was found in chronic alcoholics with liver injury. There was no apparent difference in hepatic biochemical and histological findings between chronic alcoholics with and without low Km ALDH isozyme, suggesting that acetaldehyde does not play a primary role in the pathogenesis of alcoholic liver injury.