The effects of exercise on macrophage function

Abstract

Innate immunity is our first line of defense against infectious pathogens. One of the major constituents of the innate immune system is macrophages that perform important phagocytic, regulatory and antigen presentation functions. Physically active individuals are reportedly less susceptible than sedentary individuals to viral and bacterial infections, suggesting that exercise improves immune function. Exercise increases the release of catecholamines, glucocorticoids and other factors that have immunomodulatory effects. For example, proinflammatory cytokine production from macrophages was inhibited by β 2 -adrenergic receptor (β 2 AR) agonist catecholamines, but exercise training down-regulated the expression of β 2 AR in macrophages, improving innate immune functions. In addition, the generation of suppressor macrophages by glucocorticoids that are normally induced during acute cold stress was inhibited in swimming-trained mice. Also, an inactive lifestyle leads to the accumulation of visceral fat, which is accompanied by adipose tissue infiltration by pro-inflammatory immune cells, mainly macrophages, and the development of a low-grade systemic inflammatory state. Exercise decreases chronic low-grade systemic inflammation and improves insulin sensitivity in obese individuals. Although the mechanisms behind these favorable effects of exercise are not fully understood, recent studies have shown that exercise training prevents adipose tissue infiltration by pro-inflammatory macrophages and that ghrelin expressed in macrophages functions as a mediator of the anti-inflammatory effects of exercise training. In this Review, the authors focus on the known mechanisms by which exercise exerts its effects on macrophages, and discuss the implications of these effects for the prevention and treatment of disease.

The Effects of Exercise on Spleen Fibrosis and Macrophage Number in D-Galactose-Induced Aging Rat Model

“…30,31 Other than that, increased SNS activity also initiates the release of catecholamine (adrenaline and noradrenaline), which is known as a down-regulator of lipopolysaccharides (LPS). 29 This study has some limitations. The fibrosis and macrophage data presented in the Results section showed down-trend patterns when given low and moderate-intensity treadmill exercise.…”

“…28 Exercise also causes motor center and afferent impulses to release some hypothalamic-releasing factors that will increase the secretion of ACTH. 29 Glucocorticoid, especially cortisol, is known to affect immunological processes by suppressing inflammation. 30,31 Other than that, increased SNS activity also initiates the release of catecholamine (adrenaline and noradrenaline), which is known as a down-regulator of lipopolysaccharides (LPS).…”

Physical Activity Maintain Immune Response Through TLR-2/TLR-4 Gene Expression in Type-2 Diabetes Mellitus Patient at Medan City

“…It proved that exercise could prevent macrophage pro-inflammatory infiltration to adipose tissue. But so far, there are not many research had been done to find out how was the physical activity, expression of TLR2 gene, TLR4 gene and mononuclear cell as natural immune response to T2DM patients ( 6 ).…”

Macrophage Meets the Circadian Clock: Implication of the Circadian Clock in the Role of Macrophages in Acute Lower Respiratory Tract Infection

“…Macrophage functions are reprogramed by cues derived from our daily lifestyle. Diet (i.e., nutrition), physical exercise, and aging progression has been revealed to modulate the phenotype of macrophages, defining systemic inflammatory status (Olefsky and Glass, 2010;Dall'Asta et al, 2012;Kizaki et al, 2012;Linehan and Fitzgerald, 2015;Davanso et al, 2020;Sitlinger et al, 2020;De Maeyer and Chambers, 2021;Duong et al, 2021). It has begun to be accepted that both the quantity and quality of immune cells including monocytes/macrophages exhibit a robust daily oscillation (Curtis et al, 2014;Leach and Suzuki, 2020;Shimba and Ikuta, 2020;Waggoner, 2020;Cermakian et al, 2021).…”