Changes in systemic and subcutaneous adipose tissue inflammation and oxidative stress in response to exercise training in obese black African women

Abstract

Key points: Inflammation and oxidative stress are interrelated during obesity and contribute to the development of insulin resistance; and exercise training represents a key component in the management of these conditions. Black African women, despite high gluteal subcutaneous adipose tissue (SAT) and less visceral fat, are less insulin sensitive than their white counterparts. Exercise training improved systemic oxidative stress in obese black women, which was related to gynoid fat reduction and not insulin sensitivity. Inflammatory markers changed depot-specifically in response to exercise training, increasing in gluteal SAT without changing in abdominal SAT. The increase of inflammatory state in gluteal SAT after exercise training is suggested to result from tissue remodelling consecutive to the reduction of gynoid fat but does not contribute to the improvement of whole-body insulin sensitivity in obese black South African women.

Abstract: Inflammation and oxidative stress are interrelated during obesity and contribute to the development of insulin resistance. Exercise training represents a key component in the management of obesity. We evaluated the effects of 12 weeks' combined resistance and aerobic exercise training on systemic and abdominal vs. gluteal subcutaneous adipose tissue (SAT) inflammatory and oxidative status in obese black South African women. Before and after the intervention, body composition (dual energy X-ray absorptiometry), cardio-respiratory fitness ( ${\mathrm{VO}}_{2\mathrm{peak}}$ ), serum and SAT inflammatory and oxidative stress markers were measured from 15 (control group) and 20 (exercise group) women and insulin sensitivity (S_I ; frequently sampled intravenous glucose tolerance test) was estimated. Following the intervention, ${\mathrm{VO}}_{2\mathrm{peak}}$ (9.8%), body fat composition (1-3%) and S_I (9%) improved, serum thiobarbituric acid reactive substances (TBARS) decreased (6.5%), and catalase activity increased (23%) in the exercise compared to the control group (P < 0.05), without changes in circulating inflammatory markers. The mRNA content of interleukin-10, tumour necrosis factor α, nuclear factor κB and macrophage migration inhibitory factor increased in the gluteal SAT exercise compared to the control group P < 0.05), with no changes in abdominal SAT. These changes of inflammatory profile in gluteal SAT, in addition to the reduction of circulating TBARS, correlated with the reduction of gynoid fat, but not with the improvement of S_I . The changes in systemic oxidative stress markers and gluteal SAT inflammatory genes correlated with the reduction in gynoid fat but were not directly associated with the exercise-induced improvements in S_I .

Keywords: adipose tissue; exercise training; inflammation; insulin resistance; obesity; oxidative stress.