1.
Exercise-mediated vasodilation in human obesity and metabolic syndrome: effect of acute ascorbic acid infusion.
Limberg, JK, Kellawan, JM, Harrell, JW, Johansson, RE, Eldridge, MW, Proctor, LT, Sebranek, JJ, Schrage, WG
American journal of physiology. Heart and circulatory physiology. 2014;(6):H840-7
Abstract
We tested the hypothesis that infusion of ascorbic acid (AA), a potent antioxidant, would alter vasodilator responses to exercise in human obesity and metabolic syndrome (MetSyn). Forearm blood flow (FBF, Doppler ultrasound) was measured in lean, obese, and MetSyn adults (n = 39, 32 ± 2 yr). A brachial artery catheter was inserted for blood pressure monitoring and local infusion of AA. FBF was measured during dynamic handgrip exercise (15% maximal effort) with and without AA infusion. To account for group differences in blood pressure and forearm size, and to assess vasodilation, forearm vascular conductance (FVC = FBF/mean arterial blood pressure/lean forearm mass) was calculated. We examined the time to achieve steady-state FVC (mean response time, MRT) and the rise in FVC from rest to steady-state exercise (Δ, exercise - rest) before and during acute AA infusion. The MRT (P = 0.26) and steady-state vasodilator responses to exercise (ΔFVC, P = 0.31) were not different between groups. Intra-arterial infusion of AA resulted in a significant increase in plasma total antioxidant capacity (174 ± 37%). AA infusion did not alter MRT or steady-state FVC in any group (P = 0.90 and P = 0.85, respectively). Interestingly, higher levels of C-reactive protein predicted longer MRT (r = 0.52, P < 0.01) and a greater reduction in MRT with AA infusion (r = -0.43, P = 0.02). We concluded that AA infusion during moderate-intensity, rhythmic forearm exercise does not alter the time course or magnitude of exercise-mediated vasodilation in groups of young lean, obese, or MetSyn adults. However, systemic inflammation may limit the MRT to exercise, which can be improved with AA.
2.
[Estimation of plasma vitamin A, C and E levels in patients with metabolic syndrome].
Godala, M, Materek-Kuśmierkiewicz, I, Moczulski, D, Rutkowski, M, Szatko, F, Gaszyńska, E, Kowalski, J
Polski merkuriusz lekarski : organ Polskiego Towarzystwa Lekarskiego. 2014;(215):320-3
Abstract
UNLABELLED Metabolic syndrome (MS) is a coexistence of metabolic risk factors affecting development of cardiovascular diseases. In the pathogenesis of MS there participate reactive oxygen species which are excessively produced in such elements of MS as hyperglycemia, insulin resistance and obesity. Vitamins A, C and E are an important part of the non-enzymatic antioxidative barrier in humans. The aim of the study was to estimate plasma vitamin A, C and E levels in patients with symptoms of MS. MATERIAL AND METHODS The study included 68 patients with symptoms of MS according to International Diabetes Federation criteria (2005), 37 men and 31 women, aged 34-65 years (mean age 57, 76 +/- 8, 29 years). The control group consisted of 24 healthy individuals without MS, 18 men and 6 women, aged 49-67 (mean age 58, 5 +/- 5, 6 years). Plasma vitamin A, C and E levels were estimated in patients and the control group with spectrophotometry using T60V spectrophotometer (PG Instruments). RESULTS The plasma vitamin A, C and E levels were significantly lower (p < 0.05) in MS patients than in the healthy individuals without symptoms of MS. The most significant differences in the level of antioxidative vitamins in both groups were related to vitamin C and vitamin E. CONCLUSIONS The decreased level of vitamins A, C and E points to the weakening of antioxidative barrier in patients with MS.