Interleukin-15 and Other Myokines in Chronic Alcoholics

Aims: Interleukin (IL)-15 is highly expressed in skeletal muscle, where it exerts anabolic effects, increasing protein content in muscle fibres and promoting muscle growth. Alcoholics frequently suffer myopathy. Therefore, we analyse the behaviour of IL-15 (and other myokines, such as IL-6, IL-8 and tumour necrosis factor alpha (TNF-alpha)) in alcoholics. Methods: These myokines and also malondialdehyde (MDA)-a lipid peroxidation product-were determined by radioimmunoanalytic techniques in blood samples of 35 chronic alcoholics and 13 age- and sex-matched controls, and compared with body composition, nutritional status, liver function, amount of ethanol and routine biochemical variables. Results: IL-15, IL-6, TNF-alpha, IL-8 and MDA were all higher in alcoholics than in controls; MDA and IL-6 were clearly related with liver function impairment and short-term prognosis, whereas IL-15 was higher among those who died and was related to serum bilirubin. No relation was found between IL-15 and lean mass. Conclusion: IL-15 levels were higher in alcoholics than in controls, especially among those who died within 18 months after admission. They are not related with muscle mass, intensity of alcoholism or nutritional status, but only with serum bilirubin. IL-6 showed inverse correlations with liver function, intensity of alcoholism, nutritional status, left arm muscle mass and short-term mortality.