Exercise and Adipose Tissue Immunity: Outrunning Inflammation

Abstract

Chronic inflammation is considered a precipitating factor and possibly an underlying cause of many noncommunicable diseases, including cardiovascular disease, metabolic diseases, and some cancers. Obesity, which manifests in more than 650 million people worldwide, is the most common chronic inflammatory condition, with visceral adiposity thought to be the major inflammatory hub that links obesity and chronic disease. Adipose tissue (AT) inflammation is triggered or heightened in large part by (1) accelerated immune cell recruitment, (2) reshaping of the AT stromal‐immuno landscape (e.g., immune cells, endothelial cells, fibroblasts, adipocyte progenitors), and (3) perturbed AT immune cell function. Exercise, along with diet management, is a cornerstone in promoting weight loss and preventing weight regain. This review focuses on evidence that increased physical activity reduces AT inflammation caused by hypercaloric diets or genetic obesity. The precise cell types and mechanisms responsible for the therapeutic effects of exercise on AT inflammation remain poorly understood. This review summarizes what is known about obesity‐induced AT inflammation and immunomodulation and highlights mechanisms by which aerobic exercise combats inflammation by remodeling the AT immune landscape. Furthermore, key areas are highlighted that require future exploration and novel discoveries into the burgeoning field of how the biology of exercise affects AT immunity.

Obesity and Adipose Tissue Dysfunction: From Pediatrics to Adults

“…Animal models demonstrated that as little as 4 weeks of aerobic exercise prevents conformational changes in adipose tissue [ 112 ]. In an early systematic review, physical activity with aerobic exercise inhibits adipose tissue paracrine and endocrine inflammatory responses [ 113 ]. This may result in children being less susceptible to infections.…”

“…Interestingly, leptin levels were increased in the obese pediatric populations [ 117 ] and seen in blood as early as 12 years of age [ 118 ]. In patients who had weight loss by physical activity including aerobic exercise, M1 macrophages along with inflammatory cytokines are decreased [ 113 ] proving how early interventions can diminish this inflammatory cascade.…”

The Influence of Obesity and Weight Loss on the Bioregulation of Innate/Inflammatory Responses: Macrophages and Immunometabolism

“…In general, inflammatory activation of various immune cells is associated with a marked shift toward glycolytic metabolism and lower reliance on fat oxidation. The increase in glycolysis triggers HIF1α-mediated gene transcription and cytokine production [50]. However, in a basal situation or in long-term regenerative processes after acute inflammatory responses, immune cells can use fat as an energy substrate.…”

The effect of exercise training on adipose tissue insulin sensitivity: A systematic review and meta‐analysis

“…Pharmacologically, agents targeting improvements in adipose tissue insulin sensitivity (e.g., thiazolidinediones) reduce circulating NEFA, liver fat, and hepatic fibro‐inflammatory activity 10 . Alternatively, exercise is a lifestyle therapy that may be able to improve adipose tissue insulin sensitivity through morphological and biochemical alterations within adipocytes 11–13 . Although studies have examined the impact of exercise on the sensitivity of adipose tissue to insulin, no attempt has previously been made to systematically aggregate data in this area, and it is unknown whether factors such as exercise mode, duration, intensity, and weight loss influence exercise training responses.…”