Arterial Stiffness Associated with Sympathetic Hyperactivity in Obese Individuals with Moderate to Severe Obstructive Sleep Apnea.

INTRODUCTION: Obstructive Sleep Apnea (OSA) is a chronic disorder associated with several risk factors, and increased Body Mass Index (BMI) and waist circumference are correlated with it is severity. AIM: To evaluate vascular function, central hemodynamics, and autonomic modulation in obese individuals with moderate and severe OSA. METHODS: Individuals of both sexes, aged 40-70 years and BMI ≥ 30 and < 40 kg/m2, were submitted to assessment of heart rate variability, endothelial function by flow-mediated dilatation, central parameters by oscillometry and carotid ultrasound. The sleep study was performed through a portable home sleep test device (WatchPAT). RESULTS: Patients (n = 76) were divided according to Apnea-Hypopnea Index (AHI): absent-mild group (AHI < 15 events/h, n = 30) and Moderate-Severe (MS) group (AHI ≥ 15 events/h, n = 46). The Low/High Frequency (LF/HF) ratio (0.81 ± 0.48 vs 1.39 ± 1.08 ms2, p = 0.035), Pulse Wave Velocity (PWV; 6.9 ± 0.7 vs 7.7 ± 1.6m/s, p = 0.004), vascular age (48 ± 6 vs 53 ± 9 years, p = 0.05) and mean intima-media thickness (0.59 ± 0.08 vs 0.66 ± 0.13 mm, p = 0.011) were significantly higher in the MS group. AHI was significantly correlated with PWV (r = 0.26, p = 0.024) and LF/HF ratio (r = 0.40, p < 0.001). Only in the MS group, PWV was significantly correlated with SD2/SD1 ratio (r = 0.611, p ≤ 0.001), and flow-mediated dilation with central systolic blood pressure (r = 0.364, p = 0.018), even after adjustment for age and sex. CONCLUSION: In this sample of obese individuals, moderate to severe OSA was associated with sympathetic hyperactivity and evidence of accelerated vascular aging with arterial stiffness and subclinical atherosclerosis.

Association of urinary sodium/potassium ratio with structural and functional vascular changes in non-diabetic hypertensive patients.

Studies aiming to associate the sodium/potassium (Na/K) ratio with hypertension use 24-hour urinary excretion as a daily marker of ingestion. The objective of this study was to evaluate the association between urinary Na/K ratio and structural and functional vascular alterations in non-diabetic hypertensive patients. In hypertensive patients (n = 72), aged between 40 and 70 years, both sexes (61% women), in use of hydrochlorothiazide, we measured blood pressure, 24-hour urine sample collection, assessment of carotid-femoral pulse wave velocity (cf-PWV, Complior), central hemodynamic parameters (SphygmoCor), and post-occlusive reactive hyperemia (PORH). The participants were divided according to the tertile of 24-hour urinary Na/K ratio. Each group contained 24 patients. Systolic blood pressure was higher in T2 (133 ± 9 vs 140 ± 9 mmHg, P = .029). C-reactive protein (CRP) presented higher values in T3 as compared to T1 [0.20(0.10-0.34) vs 1.19 (0.96-1.42) mg/dL, P < .001]. Higher values in T3 were also observed for aortic systolic pressure (aoSP) [119(114-130) vs 135(125-147) mmHg, P = .002] and cf-PWV (9.2 ± 1.6 vs 11.1 ± 1.5 m/s, P < .001). The urinary Na/K ratio presented significant correlations with proteinuria (r = .27, P = .023), CRP (r = .77, P < .001), cf-PWV (r = .41, P < .001), and post-occlusive reactive hyperemia on cutaneous vascular conductance (PORH CVC) (r = -.23, P = .047). By multivariate linear regression, it was detected an independent and significant association of cf-PWV with urinary Na/K ratio (R2  = 0.17, P < .001) and PORH CVC with CRP (R2  = 0.30, P = .010). Our data indicated that increased urinary Na/K ratio in non-diabetic hypertensive patients was associated with higher degree of inflammation, raised peripheral and central pressure levels, and changes suggestive of endothelial dysfunction and arterial stiffness.

Effects of Nutrients and Exercises to Attenuate Oxidative Stress and Prevent Cardiovascular Disease.

BACKGROUND: In recent years, it has become more evident that oxidative stress is involved in the development of cardiovascular disease. Indeed, reactive oxygen species seems to be the common mechanism for endothelial dysfunction, vascular inflammation and arterial stiffness, resulting in a blood pressure increase and early vascular aging. METHODS: This review presents the potential role of antioxidant nutrients and exercise for cardiovascular protection. RESULTS: Flavonoids, vitamins and minerals present in some fruits and foliage are considered natural antioxidants. In fact, fruits and vegetables contain large amounts of antioxidants. Several clinical trials have extensively studied vitamin E, beta-carotene, vitamin C, polyphenols, plus selenium and zinc. In addition, many authors have been carried out clinical trials to evaluate the mechanisms of oxidative stress attenuation after exercise. Exercise responses may vary according to the Frequency, Intensity, Time and Type (FITT) principle, making it difficult to obtain a consensus concerning the exercise properties and redox status. High-intensity interval training (HIIT) has been reported as an efficient option for metabolic adaptations in a short time. Aerobic exercises must be performed at least three times a week, for two months or more, using moderate to vigorous intensity to promote a positive effect on oxidative stress and vascular function. CONCLUSION: The recognition of appropriate nutrients and exercise with antioxidant properties may be an important supportive approach to impair early vascular aging and to prevent cardiovascular disease.