The impact of aerobic exercise training on novel adipokines, apelin and ghrelin, in patients with type 2 diabetes

BACKGROUND Accumulating data support the atheroprotective role of the novel adipokines, apelin and ghrelin. The aim of the present randomized study was to investigate the effects of aerobic exercise training on these adipokines in patients with type 2 diabetes mellitus (T2DM). MATERIAL/METHODS Fifty-four overweight (BMI >25 kg/m²) patients with T2DM, but without vascular complications, were randomized to either the aerobic exercise training group (EG, N=27), 4 times/week, 45-60 min/session; or to the control group (CG, N=27), orally instructed to increase physical activity. Clinical glycemic and lipid parameters, exercise capacity (VO₂peak), insulin, HOMA-IR, and serum levels of apelin and ghrelin were assessed at baseline and after 12 weeks. RESULTS Aerobic exercise significantly improved lipid and glycemic profile and insulin sensitivity compared to CG (p<0.05). Furthermore, between-groups comparison showed a considerable exercise-induced upregulation in apelin (p=0.007) and VO₂peak (p<0.001) levels. Negligible changes in body-weight, waist-hip ratio and ghrelin concentrations were detected within and between groups after the completion of the study (p>0.05). However, subgroup analysis revealed a considerable increment in ghrelin levels only in the exercise-treated women compared to their control counterparts (p=0.038). LDL and HOMA-IR reduction were found to be independent predictors of apelin increment in multiple regression analysis (R²=0.391, p=0.011). CONCLUSIONS In patients with T2DM, systemic, long-term, aerobic exercise exerts positive effects on apelin and ghrelin (only in women), even in the absence of significant weight loss, suggesting its pleiotropic effects.