Background: The prevalence of obesity has been increasing worldwide. Obesity is an independent risk factor for cardiovascular morbidity and mortality (1, 2). On the other hand, the reduced central arterial distensibility has implications in the pathophysiology of cardiovascular disease and has been identified as an independent risk factor for cardiovascular disease (3, 4). However, the effect of weight loss on central arterial distensibility and endothelial function in obese subjects has not yet been clarified.
Objective: The present study examined whether low-calorie diet-induced weight loss affects central arterial distensibility and endothelial function in middle-aged obese men.
Methods: Seven healthy obese men (age: 48 ± 4 yrs, body mass index: 29 ± 2 kg/m2) completed a 12-week low-calorie dietary intervention program (1,680 kcal/day). Before and after the program, we measured carotid arterial compliance (via simultaneous B-mode ultrasound and arterial applanation tonometry on the common carotid artery); β-stiffness index, an index of arterial compliance adjusted for distending pressure; aortic pulse-wave velocity (PWV), a traditional index of arterial stiffness; and plasma endothelin-1 (ET-1), a potent vasoconstrictor peptide produced by vascular endothelial cells, and nitric oxide (NO) [measured as the stable end product (nitrite/nitrate)], a potent vasodilator produced by vascular endothelial cells, concentrations in obese men.
Results: Caloric restriction significantly reduced body weight and resulted in a significant decrease in body mass index. After the weight reduction program, carotid arterial compliance significantly increased and β-stiffness index significantly decreased. In addition, PWV remarkably decreased after weight loss. Thus, weight reduction by a low-calorie diet in obese men increased central arterial distensibility. The plasma ET-1 concentration significantly decreased after the weight reduction program. The plasma concentration of NO significantly increased with weight loss. The decreased ET-1 and increased NO suggest an improvement in endothelial function. Therefore, weight reduction by a low-calorie diet in healthy obese men not only increased central arterial distensibility, but also improved their endothelial function.
Conclusions: Low-calorie diet-induced weight reduction increased central arterial distensibility in middle-aged healthy obese men. The improvements in arterial distensibility were associated with a reduction in plasma ET-1 and an increase in plasma NO, and consequently, improved endothelial function. Thus, weight loss improves central arterial distensibility and endothelial function in middle-aged healthy obese men. We propose that weight loss has a great significance for vascular function in obese men.
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