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The effect of low-level laser therapy (LLLT) on the cardiovascular system is not fully established. Since the endothelium is an important endocrine element, establishing the mechanisms of LLLT action is an important issue.The aim of the study was to evaluate the effect of transdermal LLLT on endothelial function.In this study, healthy volunteers (n = 40, age = 20-40 years) were enrolled. N = 30 (14 female, 16 male, mean age 30 ± 5 years) constituted the laser-irradiated group (LG). The remaining 10 subjects (6 women, 4 men, mean age 28 ± 5 years) constituted the control group (CG). Participants were subjected to LLLT once a day for three consecutive days. Blood for biochemical assessments was drawn before the first irradiation and 24 h after the last session. In the LG, transdermal illumination of radial artery was conducted (a semiconductor laser λ = 808 nm, irradiation 50 mW, energy density 1.6 W/cm(2) and a dose 20 J/day, a total dose of 60 J). Biochemical parameters (reflecting angiogenesis: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiostatin; antioxidative status: glutathione (GSH) and the nitric oxide metabolic pathway: symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA) and L-arginine) were assessed. In the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation. [ABSTRACT FROM AUTHOR]

Acute hypoxia increases cerebral blood flow (CBF) and ventilation (...E). It is unknown if these responses are impacted with normal aging, or in patients with enhanced oxidative stress, such as (COPD). The purpose of the study was to 1) investigate the effects of aging and COPD on the cerebrovascular and ventilatory responses to acute hypoxia, and 2) to assess the effect of vitamin C on these responses during hypoxia. In 12 Younger, 14 Older, and 12 COPD, we measured peak cerebral blood flow velocity (...P; index of CBF), and ...E during two 5-min periods of acute isocapnic hypoxia, under conditions of 1) saline-sham; and 2) intravenous vitamin C. Antioxidants [vitamin C, superoxide dismutase (SOD), glutathione peroxidase, and catalase], oxidative stress [malondialdehyde (MDA) and advanced protein oxidation product], and nitric oxide metabolism end products (NOx) were measured in plasma. Following the administration of vitamin C, vitamin C, SOD, catalase, and MDA increased, while NOx decreased. ...P and ...E sensitivity to hypoxia was reduced in Older by ~60% (P < 0.02). COPD patients exhibited similar ...P and ...E responses to Older (P > 0.05). Vitamin C did not have an effect on the hypoxic ...E response but selectively decreased the ...P sensitivity in Younger only. These findings suggest a reduced integrative reflex (i.e., cerebrovascular and ventilatory) during acute hypoxemia in healthy older adults. Vitamin C does not appear to have a large influence on the cerebrovascular or ventilatory responses during acute hypoxia. [ABSTRACT FROM AUTHOR]

Our aim was to investigate the effects of an exercise test on some indices of oxidative status and endothelial function, in trained and untrained subjects. We examined lipid peroxidation, nitric oxide metabolites (NOx) and their ratio before and after a cardiopulmonary test, using a cycloergometer. We enrolled 60 male subjects who practiced sport unprofessionally, subdivided in two groups (A and B) according to the values of VO2max. Group A included sportsmen with poor or fair aerobic fitness (VO2max <39 ml/Kg/min), group B sportsmen with average to excellent aerobic fitness (VO2max >39 ml/Kg/min). The control group included 19 male sedentary subjects. Lipid peroxidation was evaluated by detection of the thiobarbituric acid-reactive substances (TBARS); the NOx were evaluated employing the Griess reagent. At rest, in comparison with sedentary controls, an increase in TBARS, NOx and TBARS/NOx ratio was found in all sportsmen and partially in the two groups. After the cardiopulmonary test, the increase of TBARS and TBARS/NOx ratio was significantly more evident in sedentary controls than in sportsmen. No variation was observed for NOx in any group. These data suggest that sportsmen are protected against the acute oxidative stress induced by an exercise test, and that protection is not strictly dependent on the aerobic fitness. [ABSTRACT FROM AUTHOR]

Aim Alpha-thalassaemia is known to reduce intra-erythrocyte Hb S (sickle haemoglobin) concentration in sickle cell trait ( SCT) subjects. Because Hb S was shown to increase oxidative stress, the purpose of this study was to assess the effects of the coexistence of α-thalassaemia and SCT on oxidative stress markers and nitric oxide ( NO) metabolism after an acute physical exercise. Methods Forty subjects (age: 23.5 ± 2.21 years), SCT carriers ( Hb AS) or healthy subjects ( Hb AA), with (-α T) or without (- Nα T) an associated α-thalassaemia took part in the study. Plasma markers of oxidative stress [advanced oxidation protein products ( AOPP), protein carbonyl, malondialdehyde ( MDA) and nitrotyrosine], anti-oxidant defences and NO metabolism ( NOx) were measured at rest ( Trest), immediately following an incremental maximal exercise test ( Tex) and during recovery ( T1h, T2h and T24h). Results Malondialdehyde expressed as the percentage of changes from baseline was significantly higher in the Hb AS- Nα T compared with Hb AS-α T during recovery (+36.3 ± 14.1% vs. −1.8 ± 13.2% at T1h, P = 0.02; +36.6 ± 13.4% vs. −11.4 ± 12.5% at T2h, P = 0.004 and +24.1 ± 12.3% vs. −14.4 ± 11.5% at T24h, P = 0.02 in Hb AS- Nα T vs. Hb AS-α T). Compared with Hb AS- Nα T, Hb AS-α T had a higher NOx change from baseline at Tex (−23.4 ± 20.6% vs. +57.7 ± 19.3%, respectively; P = 0.005) and lower nitrotyrosine change from baseline at T1h (+7.2 ± 22.2% vs. +93.5%±29.3%, respectively; P = 0.04). Conclusion All these data suggest that the presence of α-thalassaemia may blunt the higher level of oxidative stress and the impaired bioavailability of NO observed in the SCT carriers. [ABSTRACT FROM AUTHOR]