Cytokine Response to Resistance Exercise in Children with Excess Fat and Prader-Willi Syndrome
Authors: Vuong Vincent , Haqq Andrea , Rubin Daniela 
Published: May 2024

Background: Tumor necrosis factor alpha (TNF-α) is a proinflammatory cytokine that is secreted from adipose tissue and macrophages; interleukin-6 (IL-6), secreted from adipose tissue, macrophages and skeletal muscle, has both proinflammatory and anti-inflammatory properties. Previous research showed excess adiposity leads to an increased concentration of both cytokines at rest while there is limited research on resistance exercise. Purpose: To compare IL-6 and TNF-α responses to resistance exercise in children with Prader-Willi Syndrome (PWS), a genetic cause for obesity, vs. children with normal fat mass (lean), or excess body fat (obesity) Methods: Nine children with PWS (11.4 ± 3.3 years, 45.6 ± 5.2% body fat), 11 lean children (9.2 ± 1.4 years, 18.6 ± 5.0% bodyfat), and 12 children with obesity (9.6 ± 1.3 years, 40.4 ± 5.4% body fat) participated. Children stepped onto an elevated platform wearing a weighted vest for 6 sets of 10 repetitions per leg (sets separated by 1 min of rest). Children with PWS, stepped to a platform height of 23.0 cm and wore a vest load that was computed as (20% of stature* 50% of lean body mass)/23.0 cm. For the controls, the platform height was 20% of the stature and the vest load was 50% of the lean body mass. Blood samples were obtained before (pre), immediately after (post), and during recovery from exercise (+15 and +60 min). Areas under the curve (AUC) were computed for IL-6 and TNF-α. Results: There was no group by time interaction for IL-6 ( p=0.378) but a group effect ( p=0.011) and a time effect ( p<0.001). Pairwise comparisons showed 60+ (1.065 ± 0.10 pg/mL) was higher than pre (0.660 ± 0.05 pg/mL), post (0.728 ± 0.06 pg/mL), and +15 (0.764 ± 0.066 pg/mL), p<0.001 for all. Children with PWS and children with obesity had higher IL-6 concentrations than lean children (0.943 ± 0.12 pg/mL and 0.951 ± 0.10 pg/mL vs. 0.519 ± 0.11 pg/mL, p≤0.038 for both). For TNF-α, there were no group by time interaction, time or group effects ( p≥0.420 for all). IL-6 AUC ( p=0.013) but not TNF-α AUC ( p=0.404) were different between groups. Children with PWS and children with obesity showed a higher IL-6 AUC than lean children (85.106 ± 41.81 pg/mL, 86.796 ± 33.60 pg/mL vs. 47.611 ± 21.00 pg/mL, p≤ 0.041 for both). Conclusion: There were no differences in IL-6 or TNF-α responses to exercise based on having PWS or having excess body fat in children. However, excess body fat was associated with higher IL-6 concentration and AUC. Peak concentrations for IL-6 were observed at 60 minutes after exercise similar to other studies. Potentially, IL-6 concentrations immediately post-exercise were not elevated because the exercise protocol was not of high intensity or long enough. Study funded by the US Army Medical Research and Material Command Contract W81XWH-08-1-0025 (DAR). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.