Anti-inflammatory effect of exercise training through reducing inflammasome activation-related inflammatory cytokine levels in overweight/obese populations: A systematic review and meta-analysis.

Background And Purpose: Exercise has been found to reduce chronic inflammation in obesity, however, whether exercise exerts an anti-inflammatory effect through regulating the inflammasome activation signaling in obesity remains unclear. This study aimed to investigate the effect of exercise training on circulating levels of inflammasome activation-related inflammatory cytokines in overweight/obese populations using a systematic review and meta-analysis approach.

Methods: Six databases were searched from their inception to June 12th 2021, and randomized controlled trials (RCTs) investigating the effect of exercise training on two end-products of inflammasome activation signaling IL-1β and IL-18 in overweight/obese populations were included. Data were extracted and meta-analyses were performed. Risk of bias was assessed using the Cochrane Collaboration risk assessment tool and the certainty of evidence was graded using Grading of Recommendations, Assessment, Development and Evaluation (GRADE).

Results: Of 3737 studies identified, 16 RCTs with 779 participants were included. The results demonstrated that exercise training could reduce circulating levels of inflammasome activation-related inflammatory cytokines IL-1β and IL-18 in overweight/obese populations. Subgroup analyses showed that the regulatory effect of exercise on inflammasome activation was more significant in the obese but not overweight population, in females but not in males, with low-to-moderate exercise intensity, and with the duration of exercise intervention longer than eight weeks.

Conclusion: Exercise training could regulate inflammation through reducing levels of inflammasome activation-related inflammatory cytokines in overweight/obese populations. Further research investigating the effect of exercise on other key molecules involved in the inflammasome activation signaling is highly needed.