A definitive understanding of the role of dietary lipids in determining cardio-protection (or cardio-detriment) has been elusive. Randomized trial findings have been variable and sex- specificity of dietary interventions has not been determined. In this investigation the sex-selective cardiac functional effects of three diets enriched by omega-3 or omega-6 polyunsaturated fatty acids (PUFA) or enriched to an equivalent extent in saturated fatty acid components were examined in rats after an 8 week treatment period. In females the myocardial membrane omega-6:omega-3 PUFA ratio was two-fold higher than male in the omega-6 diet replacement group. In diets specified to be high in omega-3 PUFA or in saturated fat, this sex difference was not apparent. Isolated cardiomyocyte and heart Langendorff perfusion experiments were performed, and molecular measures of cell viability assessed. Under basal conditions the contractile performance of omega-6 fed female cardiomyocytes and hearts was reduced compared with males. Omega-6 fed females exhibited impaired systolic resilience after ischemic insult. This response was associated with increased post ischemia necrotic cell damage evaluated by coronary lactate dehydrogenase during reperfusion in omega-6 fed females. Cardiac and myocyte functional parameters were not different between omega-3 and saturated fat dietary groups and within these groups there were no discernible sex differences. Our data provide evidence at both cardiac and cardiomyocyte level that dietary saturated fatty acid intake replacement with an omega-6 (but not omega-3) enriched diet has selective adverse cardiac effect in females. This finding has potential relevance in relation to women, cardiac risk and dietary management.
- dietary polyunsaturated fatty acids
- sex difference
- Copyright © 2015, American Journal of Physiology - Heart and Circulatory Physiology