Evidence of apoptosis in chronic alcoholic skeletal myopathy

Apoptosis is a common mechanism of programmed cell death that has been implicated in the pathogenesis of alcohol-induced organ damage. Experimental studies have suggested alcohol-mediated apoptosis in cardiac muscle. The relationship between skeletal and cardiac muscle damage in alcoholism led us to consider the possible role of apoptosis in the pathogenesis of skeletal myopathy. We prospectively evaluated apoptosis in skeletal muscle biopsies of 30 consecutively selected male high-dose well-nourished chronic alcohol consumers and 12 nonalcoholic controls. Alcohol consumption, evaluation of muscle strength by myometry, and deltoid muscle biopsy with immunohistochemical and morphometric analysis were performed. Apoptosis was assessed by TUNEL, BAX, and BCL-2 immunohistochemical assays. Chronic alcoholics compared with controls showed a significantly higher apoptotic index in TUNEL (2.35% +/- 0.25% versus 0.18% +/- 0.03%, P < 0.001), BAX (9.16% +/- 2.00% versus 0.66% +/- 0.22%, P < 0.001), and BCL-2 muscle assays (8.08% +/- 0.20% versus 0.83% +/- 0.20%, P = 0.001), respectively. In addition, these apoptotic indexes were higher in alcoholics with skeletal myopathy compared with in those without skeletal myopathy (3.04% +/- 0.36% versus 1.65% +/- 0.26%, P = 0.004 for TUNEL; 17.00% +/- 2.78% versus 1.33% +/- 0.22%, P < 0.001 for BAX; and 15.13% +/- 3.2% versus 1.03% +/- 0.33%, P < 0.001 for BCL-2 assays, respectively). We conclude that apoptosis is present in the skeletal muscle of high-dose alcohol consumers, mainly in those affected by myopathy. However, the specific pathogenic mechanism of apoptosis in chronic skeletal myopathy in alcoholics remains to be elucidated.