A diet supplemented with ALA-rich flaxseed prevents cardiomyocyte apoptosis by regulating caveolin-3 expression

Aims: n-3 polyunsaturated fatty acids (PUFAs) induce beneficial effects on the heart, but the mechanisms through which these effects are operated are not completely clarified yet. Among others, cardiac diseases are often associated with increased levels of cytokines, such as tumour necrosis factor-a(TNF), that cause degeneration and death of cardiomyocytes. The present study has been carried out to investigate (i) the potential anti-apoptotic effects induced by the n-3 polyunsatur-ated a-linolenic acid (ALA) in experimental models of cardiac diseases characterized by high levels of TNF, and (ii) the potential role of caveolin-3 (Cav-3) in the mechanisms involved in this process. Methods and results: An ALA-rich flaxseed diet, administered from weaning to hereditary cardiomyopathic hamsters, prevented the onset of myocardial apoptosis associated with high plasma and tissue levels of TNF preserving caveolin-3 expression. To confirm these findings, isolated neonatal mouse cardiomyocytes were exposed to TNF to induce apoptosis. ALA pre-treatment greatlyenhanced Cav-3 expression hampering the internalization of the caveolar TNF receptor and, thus, determining the abortion of the apoptotic vs. survival cascade. Conclusion" This study unveiled the Cav-3 pivotal rolein defending cardiomyocytes against the TNF pro-apoptotic action and the ALA capacity to regulate this mechanism preventing cardiac degenerative diseases.