Exercise reduces plasma lipid levels by downregulating tumor necrosis factor-alpha production by peripheral blood mononuclear cells

Tumor necrosis factor alpha (TNF-alpha), a proinflammatory/proatherogenic cytokine, has been implicated as the cause hyperlipidemia in patients with chronic inflammatory joint disease including rheumatoid arthritis, psoriatic arthritis and ankylosing spondylitis. In this study, we have measured the effect of long-term moderate intensity exercise training on blood lipid levels and on the ex vivo production of TNF-alpha by mitogen-stimulated peripheral blood mononuclear cells. Study participants underwent six-months of tri-weekly supervised training sessions, each consisted of a combination of aerobic (52%), resistance (40%), and flexibility (8%) exercises. Forty-three subjects, 25 women average age 49.7 years and 18 men average age 48.1 years, successfully completed the study. Both men and women exercised an average of 2.5 hours per week. Exercise training resulted in a 10% decrease in total cholesterol levels (P=0.0136), an 18% decrease in low density lipoprotein cholesterol levels (P=0.0043), a 20.1% decrease in total cholesterol/high density lipoprotein cholesterol ratios (P=0.0030), and a 51.5% decrease in the production of TNF-alpha (P <0.0001). On multiple regression analysis reductions in TNF-alpha correlated linearly with reductions in total cholesterol (R=0.4185, F=8.4931, P=0.0058) and low density lipoprotein cholesterol (R=0.3562, F=5.8138, P=0.0206). We conclude that exercise-related reductions in blood lipids may occur as the result of reductions in immune cell production of TNF-alpha, a cytokine with known potential to influence hepatic, adipocyte, and monocyte/macrophage regulation of lipid metabolism.  
ClinicalTrials.gov identifier: NCT04195932