Author(s): RUVIRA HERNANDO, S., RUVIRA, S., WARNIER, G., SIMON, E., DELDICQUE, L., Institution: UNIVERSITÉ CATHOLIQUE DE LOUVAIN, Country: BELGIUM, Abstract-ID: 1030

INTRODUCTION:
Subcutaneous adipose tissue (SAT) dysfunction is the primary cause of increased ectopic fat deposition (1, 2). Exacerbated production of prooxidant species and capillary rarefaction are considered among the main drivers of adipose tissue dysfunction (3). Conversely, exercise is a well-known regulator of systemic and skeletal redox balance and angiogenesis. Thus, our main aim is to elucidate whether exercise reverses unhealthy adipose tissue expansion.
METHODS:
Twenty-three sedentary male participants (aged 30-55) were recruited and separated according to their fat percentage (<25%: lean; >25% obese) after DXA scan (HOLOGIC, DiscoveryW[S/N 84165]). The subjects were enrolled in a supervised training on a cycle ergometer (Cyclus II; RBM Electronics, Leipzig, Germany) for 12 weeks. The training consisted of three sessions of 30 min per week at 60% of VO2 peak, then increased to 70% and 80% from baseline at week 4 and 8. Three abdominal SAT biopsies were taken at different time points: 1) baseline 2) post exercise (immediately after the first bout of exercise) and, 3) post-training (after 12-week training). mRNA and protein levels were measured using RT-qPCR and Western Blotting techniques. A mixed-effects analysis was performed, with Tukey's or Sidak's post hoc tests used for multiple comparisons between groups and timepoints respectively.
RESULTS:
No anthropometric changes were found after 12-week of training, in either the lean or obese groups. Exercise training reduced the mRNA levels of nuclear factor erythroid 2-related factor 2 (Nrf2; P=0.030), glutathione peroxidase 1 (GPx= P:0.016), catalase (CAT; P= 0.002) and superoxide dismutase 1 (SOD1; P=0.009) in both groups. Vascular endothelial growth factor (VEGF) mRNA levels showed a group effect (P=0.049) with higher levels observed in the lean group compared to the obese group. Meanwhile, NADPH oxidase 2 (NOX2) tended to decrease (P=0.084) after training in both groups. Regarding protein expression, no effect was found in peroxiredoxin 6 (PRDX6), SOD2, SOD3 and CAT protein levels. Increased PRDX1 levels (P=0.025) were found in lean participants compared to obese participants, independently of the timepoint of the study. Higher lipid oxidation was found in the obese group (P=0.011) and was reduced after training (P=0.005). Levels of CD31 remained constant in both groups prior to and following the training period.
CONCLUSION:
This study demonstrates that three 30-min sessions of low-intensity aerobic exercise per week for twelve weeks are sufficient to promote redox adaptations and reduce lipid peroxidation in obese individuals. However, low-intensity exercise demonstrated no effect on SAT capillarisation.
(1) Ioannidou A. Obes Rev. 2022; (2) Luo J. Obesity (Silver Spring). 2025; (3) AlZaim I. Nat Rev Endocrinol. 2023.