Obesity, Inflammation, Toll-Like Receptor 4 and Fatty Acids

Abstract

Obesity leads to an inflammatory condition that is directly involved in the etiology of cardiovascular diseases, type 2 diabetes mellitus, and certain types of cancer. The classic inflammatory response is an acute reaction to infections or to tissue injuries, and it tends to move towards resolution and homeostasis. However, the inflammatory process that was observed in individuals affected by obesity and metabolic syndrome differs from the classical inflammatory response in certain respects. This inflammatory process manifests itself systemically and it is characterized by a chronic low-intensity reaction. The toll-like receptor 4 (TLR4) signaling pathway is acknowledged as one of the main triggers of the obesity-induced inflammatory response. The aim of the present review is to describe the role that is played by the TLR4 signaling pathway in the inflammatory response and its modulation by saturated and omega-3 polyunsaturated fatty acids. Studies indicate that saturated fatty acids can induce inflammation by activating the TLR4 signaling pathway. Conversely, omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid and docosahexaenoic acid, exert anti-inflammatory actions through the attenuation of the activation of the TLR4 signaling pathway by either lipopolysaccharides or saturated fatty acids.

Lipopolysaccharide Alters Thermogenic and Inflammatory Genes in White Adipose Tissue in Mice Fed Diets with Distinct 18‐Carbon Fatty‐Acid Composition

“…Our work (Ajuwon and Spurlock, 2005) and those of others (Glass and Olefsky, 2012;Kim et al, 2015) have shown that dietary fatty acids play key roles in regulating inflammation and thermogenesis. Saturated fatty acids (SFA) and n-6 polyunsaturated fatty acids (PUFA) activate inflammatory signals (Ajuwon and Spurlock, 2005;Glass and Olefsky, 2012), whereas long-chain n-3 PUFA exert anti-inflammatory effects by inhibiting production of proinflammatory eicosanoids and by stimulating production of eicosanoids with lower inflammatory potency (Rogero and Calder, 2018). Therefore, consumption of diets with a low n-6:n-3 ratio could decrease the risk of inflammation-associated diseases (Alvheim et al, 2013;Jeyapal et al, 2018).…”

The impact of nutrition on COVID-19 susceptibility and long-term consequences

“…This triggers activation of canonical inflammatory signaling pathways that produce proinflammatory mediators and other effectors of the innate immune system (Rogero and Calder, 2018). Furthermore, consumption of a HFD in mice increased macrophage infiltration to lung tissue, specifically in the alveoli (Tashiro et al, 2017).…”

Protective Effects of Anthocyanins in Obesity‐Associated Inflammation and Changes in Gut Microbiome

“…[9] TLR4 is similarly activated by saturated fatty acids, commonly also increased in obesity through dietary intakes or endogenous fatty acid synthesis. [10] The gut microbiome is currently one of the most rapidly growing areas of research due to its ability to modulate many signaling effects in the body that contribute to important local and systemic health implications. [21] Gut microbiota contributes to maintaining nutrition level in the body by taking part in food digestion, especially the fermentation of indigestible polysaccharides, as well Table 4.…”

“…These, in turn, induce inflammatory responses in adipose tissue via toll‐like receptors (TLRs) . TLR4 is similarly activated by saturated fatty acids, commonly increased in obesity through dietary intake or endogenous fatty acid synthesis . Figure shows the modulatory effects of anthocyanins on gut microbiota and adipose tissue inflammation.…”