Cellular and molecular players in adipose tissue inflammation in the development of obesity-induced insulin resistance

Abstract

There is increasing evidence showing that inflammation is an important pathogenic mediator of the development of obesity-induced insulin resistance. It is now generally accepted that tissue-resident immune cells play a major role in the regulation of this obesity-induced inflammation. The roles that adipose tissue (AT)-resident immune cells play have been particularly extensively studied. AT contains most types of immune cells and obesity increases their numbers and activation levels, particularly in AT macrophages (ATMs). Other pro-inflammatory cells found in AT include neutrophils, Th1 CD4 T cells, CD8 T cells, B cells, DCs, and mast cells. However, AT also contains anti-inflammatory cells that counter the pro-inflammatory immune cells that are responsible for the obesity-induced inflammation in this tissue. These anti-inflammatory cells include regulatory CD4 T cells (Tregs), Th2 CD4 T cells, and eosinophils. Hence, AT inflammation is shaped by the regulation of pro- and anti-inflammatory immune cell homeostasis, and obesity skews this balance towards a more pro-inflammatory status. Recent genetic studies revealed several molecules that participate in the development of obesity-induced inflammation and insulin resistance. In this review, the cellular and molecular players that participate in the regulation of obesity-induced inflammation and insulin resistance are discussed, with particular attention being placed on the roles of the cellular players in these pathogeneses.

Increased fat cell size: a major phenotype of subcutaneous white adipose tissue in non-obese individuals with type 2 diabetes

“…CD8 + T cells, B cells, neutrophils, dendritic cells and mast cells [5,6]. The overall consequence of these changes is alteration of adipokine and cytokine secretion, which contributes to the development of systemic insulin resistance and type 2 diabetes [7,8].…”

Examination of myeloperoxidase activity, as an indicator of inflammation in obese participants with metabolic syndrome

“…Body Mass Index, BMI) preko 30 kg/m2 [1]. Gojaznost je povezana sa razvojem najčešćih savremenih humanih bolesti, kao što su koronarna srčana bolest, hipertenzija, diabetes mellitus tip 2 i dr. Brojna istraživanja ukazuju na udruženost perzistentne hronične inflamacije niskog stepena i gojaznosti [2]. Masno tkivo funkcioniše i kao endokrini organ, zbog sposobnosti adipocita da produkuju brojne biološki aktivne supstance -adipocitokine.…”

A weighty problem…

“…7 In addition, inflammation is important in the pathogenesis of obesity-induced insulin resistance. 8 So, depression could arise from inflammation and other biochemical changes resulting from obesity's metabolic abnormalities. 6 • Obese people often endure considerable stigma and withdraw from rewarding or pleasurable activities, which potentially triggers or exacerbates depression.…”