Dietary conjugated linoleic acids promote fatty streak formation in the C57BL/6 mouse atherosclerosis model

Abstract

Conjugated linoleic acids (CLA) are positional isomers of linoleic acid which have been suggested by some to possess antiatherosclerotic properties. To test this hypothesis, three groups of twenty C57BL/6 mice were fed on atherogenic diets containing: 5 g CLA/kg, 2⋅5 g CLA + 2⋅5 g linoleic acid/kg or 5 g linoleic acid/kg. All diets were fed for 15 weeks and contained (g/kg): triacylglycerol 145, free fatty acids 5, cholesterol 10 and cholic acid 5. At the completion of the experimental period, when data from both groups fed on CLA were combined, dietary CLA did not produce significant differences in body weight, serum total cholesterol concentration or serum HDL-cholesterol concentration. However, mice receiving CLA developed a significantly higher serum HDL-cholesterol : total cholesterol ratio and a significantly lower serum triacylglycerol concentration than controls. Despite causing a serum lipoprotein profile considered to be less atherogenic, the addition of CLA to the atherogenic diet increased the development of aortic fatty streaks. Considering the increased atherogenesis associated with dietary CLA in the present study, and the failure to demonstrate a significant beneficial effect of CLA in other animal studies, there is currently no conclusive evidence to support the hypothesis that CLA protect against atherogenesis.

Dietary fatty acids and human health

“…A more recent study in mice, fed an atherogenic diet with addition of either 2.5 or 5.0 g CLA . kg -1 , suggested greater lipid accumulation in CLA fed animals [85]. At the present time these data make it difficult to conclude anything with respect to possible effects of CLA against atherogenesis in humans.…”

Anti-obesity Effect of Monascus pilosus Mycelial Extract in High Fat Diet-induced Obese Rats

“…While, FER in MPM (0.13) was slightly lower than those of HF and CLA (0.18~0.19), fecal weight in all experimental groups were not significantly different. Many studies reported that conjugated linoleic acid (CLA), which is widely distributed in nature, could have antimutagenicity, anti-cancer, anti-hypertension and anti-dibetic effect, and anti-obese effect via inhibition of body fat [Ip and Scimeca 1997;Munday et al, 1999;Park et al, 1999]. On the other hand, immunostimulatory response growth factor-induced catabolic response is decreased by CLA [Miller et al, 1994].…”

Os efeitos do ácido linoléico conjugado no metabolismo animal: avanço das pesquisas e perspectivas para o futuro

“…Os autores encontraram redução não somente de LDL-colesterol, mas também de lipoporoteína de alta densidade (HDL-colesterol), além de um aumento de lipoproteína de muito baixa densidade (VLDL-triacilglicerol), quando 1,5% do isômero trans-10, cis-12 foi administrado durante 8 semanas, associado a uma dieta hipercolesterolê-mica. Também contraditoriamente, Munday et al 70 não observaram redução de aterosclerose em camundongos. Aparentemente os motivos pelos quais os resultados são diferentes é desconhecido.…”