A high omega-3 fatty acid diet rapidly changes the lipid composition of cardiac tissue and results in cardioprotection

Abstract

The present study was designed to ascertain the effects of 3 diets with different omega-3/6 fatty acid ratios on infarct size and the modifications that these diets induce in the lipid composition of cardiac tissue. Sprague-Dawley rats were fed omega-3/6 fatty acid diets with 1:1, 1:5, or 1:20 ratios for at least 10 days, followed by occlusion of the left anterior descending artery for 40 min and 24 h of reperfusion. Infarct size was significantly smaller in the 1:1 group than in the other groups. Significantly higher concentrations of the omega-3 fatty acids eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid were found in the 1:1 group than in the other groups. Omega-6 polyunsaturated fatty acid levels were similar between groups, although they were higher in the 1:5 and 1:20 groups than in the 1:1 group. Margaric acid concentrations were higher in the 1:1 group than in the other groups. Docosahexaenoic acid levels in cardiac tissue and infarct size were significantly correlated with no other significant links being apparent. The present study indicated that a 1:1 omega-3/6 fatty acid ratio protected against ischemia and was associated with increased omega-3 fatty acid composition of cardiac tissue.

Cardioprotective Effects of Omega-3 Polyunsaturated Fatty Acids: Dichotomy between Experimental and Clinical Studies

“…Although the mechanisms by which omega-3 PUFA are cardioprotective are essentially unknown, multiple hypotheses have been proposed in the literature ( Figure 1 ). First, omega-3 PUFA have anti-inflammatory properties owing to their incorporation in cell membrane phospholipids [ 15 ], can be transformed into 3-series prostaglandins and 5-series leukotrienes. They have been identified as less aggressive biological molecules than Arachidonic acid-derived metabolites.…”

“…The presence of EPA and DHA decreases cyclooxygenase-2 (COX-2) gene expression [ 20 ], although this has not been universally observed [ 21 ], by a mechanism involving the inhibition of NF-κB [ 20 ]. This effect results in a reduction of the inflammatory response, which could be beneficial for the ischemic myocardium [ 12 , 13 , 15 ].…”

“…Others argue that omega-6 and omega-3 PUFA are metabolized by the same desaturation/elongation pathway and could thus influence long-chain PUFA content, which could reduce the beneficial effect of omega-3 PUFA. In a rat MI model, we observed that increased omega-6 and decreased omega-3 PUFA resulted in infarct size augmentation, indicating that the omega-3/6 fatty acid ratio may alter infarct size [ 15 ]. These findings are similar to what we have observed previously [ 13 ] and suggest that omega-6 PUFA may nullify the beneficial effect of omega-3 PUFA.…”

Heart Histopathology and Mitochondrial Ultrastructure in Aged Rats Fed for 24 Months on Different Unsaturated Fats (Virgin Olive Oil, Sunflower Oil or Fish Oil) and Affected by Different Longevity

“…Anti-inflammatory and cardioprotective properties have been attributed to fish oil, especially because of its high content of n-3 fatty acids [48,49,50]. This effect could be due to the incorporation of fatty acids to cell membrane phospholipids that can be further transformed into prostanoids endowed with anti-inflammatory properties or less pro-inflammatory effect, or just because the promotion of a lower n-6/n-3 ratio in the membranes of animals fed on this dietary treatment [13,51]. Other mechanisms concerning the anti-inflammatory properties of n-3 PUFA have been described, such as the modulation of gene expression of mediators involved in inflammation [13] or reduced production of inflammatory cytokines [52].…”

“…Dietary fatty acids upon ingestion are incorporated into biological membranes, including the mitochondrial membrane, contributing to cell structure and at the same time modulating many of its properties. In addition, they are utilized in energy production or converted into longer and more unsaturated fatty acids, which may give rise to biological compounds that may affect a variety of biological processes [13,14,15,16]. Besides, changes in mitochondrial fatty acid profile can modulate its susceptibility to oxidation in aging [17].…”