Low-grade chronic inflammation is attenuated by exercise training in obese adults through down-regulation of ASC gene in peripheral blood: a pilot study

Abstract

Background: Obesity is characterized by low-grade chronic inflammation and an excess of adipose tissue. The ASC gene encodes a protein that is part of the NLRP3 inflammasome, a cytosolic multiprotein complex that is associated with inflammation and metabolic alterations. To our knowledge, there is no evidence regarding ASC gene activity in obese adults in response to lifestyle modifications.

Purpose: To evaluate the effect of hypocaloric diet and moderate-intensity structured exercise intervention on ASC gene expression and inflammatory markers in obese adults.

Methods: Thirty-seven obese individuals aged 25 to 50 years were randomized to the hypocaloric diet exercise group or hypocaloric diet group. The participants underwent a 4-month follow-up. Electrical bioimpedance was used for body composition analysis. Biochemical data were analyzed by dry chemistry and insulin levels by ELISA. ASC gene expression from peripheral blood was performed using real-time PCR. Dietary data was collected through questionnaires and analyzed using the Nutritionist Pro™ software. Quantification of cytokines was conducted using Bio-Plex Pro™ Human cytokine. The Astrand-Ryhming test was used to estimate the maximum oxygen volume and design the moderate-intensity structured exercise program ~ 75% heart rate (HR) RESULTS: After the intervention, both study groups significantly improved body composition (decreased weight, fat mass, waist circumference and abdominal obesity, p < 0.05). Besides, the diet-exercise group significantly decreased ASC mRNA expression, MCP-1, and MIP-1β inflammatory cytokines compared to the diet group (p < 0.05). While in the diet group, MCP-1 and IL-8 exhibited significantly decreased levels (p < 0.05). In the diet-exercise group, a positive correlation between the atherogenic index and waist circumference was found (r = 0.822, p = 0.011), and a negative correlation was observed between the delta of ASC mRNA expression and IL-10 levels at the end of the intervention (r = - 0.627, p = 0.019).

Conclusion: Low-grade chronic inflammation was attenuated through individualized exercise prescription and our findings highlight the role of the ASC gene in the inflammation of obese adults.

Trial registration: ClinicalTrials.gov , number NCT04315376 . Registered 20 March 2020-retrospectively registered.

Keywords: Diet; Exercise; Inflammation; Nutrition.

Fig. 1

Flowchart of patient selection

Fig. 2

ASC mRNA expression by group over time. The results are shown as mean ± standard error of the mean. a ASC mRNA expression at baseline (time 0) between groups. b ASC mRNA at fourth month of intervention (time 4) between groups. c Change post-pre of each study group. *p = 0.043, **p = 0.030

Fig. 3

Post-intervention cytokine levels. The results are shown as mean ± standard error mean. a The diet group significantly decreased IL-8 levels after 4 months of diet intervention (time 4) (*p = 0.005). b Both groups significantly decreased MCP-1 levels after 4 months of the intervention (control group *p = 0.021, exercise group *p = 0.011). c Only the diet-exercise group significantly decreased MIP-1β after 4 months of the intervention (*p = 0.008)

Fig. 4

Correlation coefficients within the exercise-diet group. a The exercise-diet group showed a positive correlation between the atherogenic index and waist circumference (p = 0.011). b The same intervention group showed a negative correlation between the delta of ASC mRNA expression and the delta of IL-10 levels after the intervention (p = 0.035). Statistical analysis was adjusted for age, gender, and final fat percentage