Effect of fatty acids on leukocyte function

Fatty acids have various effects on immune and inflammatory responses, acti ng as intracellular and intercellular mediators. Polyunsaturated Fatty acid s (PUFAs) of the omega-3 family have overall suppressive effects, inhibitin g lymphocyte proliferation, antibody and cytokine production, adhesion mole cule expression, natural killer cell activity and triggering cell death. Th e omega-6 PUFAs have both inhibitory and stimulatory effects. The most stud ied of these is arachidonic acid that can be oxidized to eicosanoids, such as prostaglandins, leukotrienes and thromboxanes, all of which are potent m ediators of inflammation. Nevertheless, it has been found that many of the effects of PUFA on immune and inflammatory responses are not dependent on e icosanoid generation. Fatty acids have also been found to modulate phagocyt osis, reactive oxygen species production, cytokine production and leukocyte migration, also interfering with antigen presentation by macrophages. The importance of fatty acids in immune function has been corroborated by many clinical trials in which patients show improvement when submitted to fatty acid supplementation. Several mechanisms have been proposed to explain fatt y acid modulation of immune response, such as changes in membrane fluidity and signal transduction pathways, regulation of gene transcription, protein acylation, and calcium release. In this review, evidence is presented to s upport the proposition that changes in cell metabolism also Flay an importa nt role in the effect of fatty acids on leukocyte functioning, as fatty aci ds regulate glucose and glutamine metabolism and mitochondrial depolarizati on.