Effects of fatty acids and dietary lipids on cells of the immune system

Abstract

Effets des acides gras et des lipides de l'alimentation sur les cellules du systi2me immunitaire R E S U M ELa synthkse des acides gras de novo fournit de l'acide palmitique. Celui-ci peut Ctre allongC jusqu'h l'acide stCarique, un substrat de Pa Ay-dCsaturase, donnant ainsi de l'acide olkique (18:ln-9). Les animaux ne posskdent pas les enzymes A12-ou A15-dCsaturase qui produisent les acides linolCic (18:2n-6) et a-1inolCique (18:3n-3) respectivement; ces enzymes se trouvent dans des plantes qui contiennent donc des proportions ClevCes d'acides gras polyinsaturks n-6 et/ou n-3 (AGPI). Etant donn6 que ces acides gras son nkcessaires pour la structure et la fonction de la membrane, elles doivent Ctre consommkes dans le regime des animaux, et sont donc appelkes acides gras essentiels. Aussi bien les animaux que les plantes posskdent les enzymes pour allonger et dksaturer les acides dksaturks palmitique, olkique, linolkique et a-linolknique. I1 rksulte des actions de ces enzymes que quatre familles distinctes de AGPI existent (n-7, n-9, n-6 et n-3

Immunomodulatory and anti-inflammatory effects of n-3 polyunsaturated fatty acids

“…Studies concerning eicosanoid synthesis by lymphocytes have proved controversial (see Goldyne, 1988). Many studies indicate that lymphocytes do not synthesize cyclooxygenase or lipoxygenase products (for references, see Goldyne, 1988;Calder, 1996b). Nevertheless, lymphocytes contain similar amounts of arachidonic acid in their membrane phospholipids to macrophages and mitogen-stimulated lymphocytes release arachidonic acid extracellularly.…”

Polyunsaturated Fatty Acids, Ulcerative Colitis and Cancer Prevention

“…On the other hand, an excessive amount of n-6 PUFA, in diet poor in n-3 PUFA, can contribute to PGE 2 , TXA2 and LTB 4 overproduction -potent inflammatory mediators. Eicosanoids produced from EPA (n-3 PUFA) are, in general, less active in inflammatory process than derived AA eicosanoids (Calder 1996, Kikuchi et al 1998. The inflammatory response is designed to remove the inciting stimulus and resolve tissue damage.…”

Production of TNF-α, nitric oxide and hydrogen peroxide by macrophages from mice with paracoccidioidomycosis that were fed a linseed oil-enriched diet

“…Similar results have been observed in regard to H 2 O 2 production. It has previously been demonstrated that peritoneal macrophages from mice that were fed on a diet supplemented with fish oil over a period of eight weeks produced more H 2 O 2 in response to stimulation by a phorbol ester than peritoneal macrophages from mice fed on a diet supplemented with coconut oil (Calder 1996).…”

“…Because n-3 PUFA-rich diets can affect the production of these eicosanoids, it is expected that these fatty acids can directly affect cytokine production (Calder 1996(Calder , 2002.…”