The impact of dietary fatty acids on macrophage cholesterol homeostasis.

The impact of dietary fatty acids in atherosclerosis development may be partially attributed to their effect on macrophage cholesterol homeostasis. This process is the result of interplay between cholesterol uptake and efflux, which are permeated by inflammation and oxidative stress. Although saturated fatty acids (SAFAs) do not influence cholesterol efflux, they trigger endoplasmic reticulum stress, which culminates in increased lectin-like oxidized LDL (oxLDL) receptor (LOX1) expression and, consequently, oxLDL uptake, leading to apoptosis. Unsaturated fatty acids prevent most SAFAs-mediated deleterious effects and are generally associated with reduced cholesterol efflux, although α-linolenic acid increases cholesterol export. Trans fatty acids increase macrophage cholesterol content by reducing ABCA-1 expression, leading to strong atherosclerotic plaque formation. As isomers of conjugated linoleic acid (CLAs) are strong PPAR gamma ligands, they induce cluster of differentiation (CD36) expression, increasing intracellular cholesterol content. Considering the multiple effects of fatty acids on intracellular signaling pathways, the purpose of this review is to address the role of dietary fat in several mechanisms that control macrophage lipid content, which can determine the fate of atherosclerotic lesions.

The role of dietary fatty acids in the pathology of metabolic syndrome.

Dysfunctional lipid metabolism is a key component in the development of metabolic syndrome, a very frequent condition characterized by dyslipidemia, insulin resistance, abdominal obesity and hypertension, which are related to an elevated risk for type 2 diabetes mellitus. The prevalence of metabolic syndrome is strongly associated with the severity of obesity; its physiopathology is related to both genetics and food intake habits, especially the consumption of a high-caloric, high-fat and high-carbohydrate diet. With the progress of scientific knowledge in the field of nutrigenomics, it was possible to elucidate how the majority of dietary fatty acids influence plasma lipid metabolism and also the genes expression involved in lipolysis and lipogenesis within hepatocytes and adipocytes. The aim of this review is to examine the relevant mechanistic aspects of dietary fatty acids related to blood lipids, adipose tissue metabolism, hepatic fat storage and inflammatory process, all of them closely related to the genesis of metabolic syndrome.