Why fish oil fails: a comprehensive 21st century lipids-based physiologic analysis

The effect of high doses of ω-3 fatty acid on the structure of the gastrocnemius muscle and on the lipidic profile of Wistar rats submitted to swimming

OBJECTIVES

Evidence suggests that ω-3 fatty acids (FA) may have an anabolic effect on skeletal muscle. However, questions about dosage, frequency, combined protein supplementation, or different physical exercises remain unanswered. The aim of this study was to quantify by stereology whether supplementation with high dosages of ω-3 FA combined with swimming has an anabolic effect on the skeletal musculature and on the lipid profile of rats.

METHODS

Sixty male Wistar rats were divided into four groups: placebo sedentary (PS), ω-3 FA sedentary (ω-3 S), placebo exercise (PE), and ω-3 FA exercise (ω-3 E). The animals in the PE and ω-3 E groups were submitted to swimming 5 d/wk, with an overload of 15% of body weight. The animals received ω-3 FA or olive oil (placebo) by gavage. After sacrifice, blood samples and the gastrocnemius muscle were collected for analysis.

RESULTS

Results from this study did not show a difference in the cross-sectional areas of the gastrocnemius muscle between groups. The administration of high doses of ω-3 FA reduced plasmatic concentrations of low-density lipoprotein. Additionally, an interaction effect was observed between physical exercise and supplementation with ω-3 on levels of high-density lipoprotein. Therefore, the association between these two treatments increased high-density lipoprotein levels.

CONCLUSIONS

The administration of high doses of ω-3 associated with physical activity may be beneficial in the treatment of dyslipidemia. High doses of ω-3 FA do not cause muscle mass alteration.

N-3 polyunsaturated fatty acids decrease levels of doxorubicin-induced reactive oxygen species in cardiomyocytes -- involvement of uncoupling protein UCP2

BACKGROUND

Use of the chemotherapeutic drug doxorubicin (DOX) is associated with serious cardiotoxicity, as it increases levels of reactive oxygen species (ROS). N-3 polyunsaturated fatty acid dietary supplements can be of benefit to patients undergoing cancer therapy. The aims of this study were to determine whether DOX-induced cardiotoxicity is related to mitochondrial uncoupling proteins and whether eicosapentaenoic acid (EPA, C20:5 n-3) or docosahexaenoic acid (DHA, C22:6 n-3) affects DOX-induced cardiomyocyte toxicity.

RESULTS

Treatment of H9C2 cells with DOX resulted in decreased cell viability and UCP2 expression. Treatment with 100 μM EPA or 50 μM DHA for 24 h resulted in a maximal mitochondria concentration of these fatty acids and increased UCP2 expression. Pretreatment with 100 μM EPA or 50 μM DHA prevented the DOX-induced decrease in UCP2 mRNA and protein levels, but these effects were not seen with EPA or DHA and DOX cotreatment. In addition, the DOX-induced increase in ROS production and subsequent mitochondrial membrane potential change (∆ψ) were significantly attenuated by pretreatment with EPA or DHA.

CONCLUSION

EPA or DHA pre-treatment inhibits the DOX-induced decrease in UCP2 expression, increase in ROS production, and subsequent mitochondrial membrane potential change that contribute to the cardiotoxicity of DOX.

Endocannabinoids, related compounds and their metabolic routes

Endocannabinoids are lipid mediators able to bind to and activate cannabinoid receptors, the primary molecular targets responsible for the pharmacological effects of the Δ⁹-tetrahydrocannabinol. These bioactive lipids belong mainly to two classes of compounds: N-acylethanolamines and acylesters, being N-arachidonoylethanolamine (AEA) and 2-arachidonoylglycerol (2-AG), respectively, their main representatives. During the last twenty years, an ever growing number of fatty acid derivatives (endocannabinoids and endocannabinoid-like compounds) have been discovered and their activities biological is the subject of intense investigations. Here, the most recent advances, from a therapeutic point of view, on endocannabinoids, related compounds, and their metabolic routes will be reviewed.