Fatty acid metabolism in macrophages: a target in cardio-metabolic diseases

Purpose of review Recent studies have highlighted that macrophages dynamically and autonomously handle all the facets of fatty acid (FA) metabolism including FA oxidation and FA synthesis as well as the synthesis of monounsaturated FAs and long chain n-3 and n-6 polyunsaturated FAs. Recent findings Macrophage M2 polarization is associated with an increase of FA oxidation. However, whether increased FA oxidation simply correlates with or is required for M2 polarization needs to be further evaluated. Macrophage M1 polarization is associated with the activation of FA synthesis, which directly contributes to the inflammatory response and affects cholesterol homeostasis and neutral lipid accumulation. Finally, recent evidences suggest that macrophages are able to autonomously produce signaling monounsaturated FAs, such as palmitoleic acid (C16 : 1 n-7), and long chain n-3 and n-6 polyunsaturated FAs, such as arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. This pathway is regulated by liver X receptors and has significant consequences on inflammation and on the FA composition of atheroma plaques. Summary These studies shed new light on the tight relationship between FA metabolism, macrophage polarization, and M1/M2 macrophage functions. These processes may have major consequences for atherosclerosis pathogenesis as well as other metabolic disorders.