Relationship of circulating spexin with markers of cardiovascular disease: a pilot study in adolescents with obesity.

PURPOSE: Spexin, a novel peptide, has potential implications in obesity, satiety and energy homeostasis. The current study examined the relationship of spexin with various biomarkers of cardiovascular disease and endothelial function in adolescents with obesity. METHODS: Nineteen adolescents with obesity (age, 15.8 ± 1.7 years) were studied. Spexin, leptin and various cardiovascular disease biomarkers were measured. Endothelial function was assessed by high-resolution Doppler ultrasonography of the right brachial artery. RESULTS: Spexin concentration (median [interquartile range] 0.38 ng/mL [0.29-0.59 ng/mL]) was inversely correlated (r = -0.50, P = 0.03) with leptin. When participants were clustered into two groups ('high spexin and low leptin' vs. 'low spexin and high leptin'), the odds of having 'low spexin and high leptin' in participants with higher hs-CRP (≥ 3 mg/L) were 12.25 times (95 per cent CI -1 to139, P = 0.026) higher than those of participants with lower hs-CRP (<3 mg/L). Spexin levels, however, were not associated with measures of endothelial function. CONCLUSIONS: The inverse association between spexin and leptin and the presence of higher concentrations of hs-CRP in adolescents with obesity in the setting of 'low spexin and high leptin' suggest a potential role for spexin in the regulation of satiety and certain cardiovascular risk factors in children with obesity.

Does exercise intensity affect blood pressure and heart rate in obese adolescents? A 6-month multidisciplinary randomized intervention study.

BACKGROUND: Aerobic exercise improves cardiovascular health in general, but whether the impact varies with exercise intensity is not clear. OBJECTIVE: The aim of the current study was to compare the effects of a high-intensity aerobic exercise training (HIT) vs. a low-intensity aerobic exercise training (LIT) on blood pressure (BP), heart rate (HR) and heart rate variability (HRV) in obese adolescents. METHODS: Forty-three (13-18 years) Tanner stage (III-IV) matched obese adolescents were studied in a randomized trial of either HIT (corresponding to the ventilatory threshold I; n = 20) or LIT (corresponding to 20% below the ventilatory threshold I; n = 23) programme for a period of 6 months. All participants also received a multidisciplinary therapy that included nutritional, psychological and clinical counselling. Both HIT and LIT sessions were isocaloric, with energy expenditure set at 350 kcal. BP, HR and HRV were measured along with markers of body adiposity and insulin resistance before and after the respective interventions. RESULTS: The participants in both groups had similar physical and clinical characteristics. After the 6-month intervention, systolic, diastolic and mean BP decreased (P < 0.05, for all) similarly in both groups, whereas waist circumference, HR and HRV showed beneficial changes only in the HIT group (P < 0.05). CONCLUSION: Aerobic exercise training set at a high intensity compared with the low intensity appears to have additional benefits on abdominal obesity and cardiovascular health in that it enhances the parasympathetic and autonomic modulation of the heart in obese adolescents.