g. deranged metabolic homeostasis such as diabetes and hyperlipidemia, as well as in obesity and peripheral artery disease, but has not as yet been studied during smoke exposure in presumably healthy subjects with the scope to study a presumed counteractive effect by https://www.selleckchem.com/screening/chemical-library.html oral antioxidants. In this study, TtP was prolonged after smoking, demonstrating a prompt adverse effect of smoking on the microcirculation, consistent with findings in other studies [19,32,37,73]. However, two weeks of oral treatment with ascorbate significantly reduced TtP (p < 0.002) and also prevented the prolongation of TtP beyond baseline after smoking
(p < 0.03). Treatment with vitamin E had no significant effect on TtP either before or after smoking. Differences between these vitamins have previously been shown and may be an effect of the different solubilities of the two antioxidants . Ascorbate, a potent major water-soluble antioxidant, may scavenge free radicals in the circulation, intercellular fluid, and cytosol. It is also important for the maintenance and regeneration of other antioxidants. Vitamin E, by contrast, is a lipid-soluble micronutrient able to prevent
formation selleck of lipid hydroperoxides and to scavenge peroxynitrite radicals, with a potential to exert its actions within lipoproteins or within the vessel wall. Some previous studies have reported on the positive effects of oral ascorbate treatment on FMD [50,60,64]. It is reasonable to ascribe such an effect to the antioxidative capacity of ascorbate, although this has
not formally been proven. Oral vitamin E has also been reported Cepharanthine to improve FMD [41,44]. However, in animal studies, it has been shown that supplementing the diet of hamsters with vitamin C prevented microcirculatory dysfunction when subsequently exposed to cigarette smoke, but that no such inhibitory effect was observed with vitamin E . Overall, the reported results of treatment with antioxidants have been variable in the literature and the majority of studies with positive results used acute administration of supraphysiological doses [20,25,34,42]. It is thus of interest to study the in vivo effects of more clinically relevant doses  as in this study after a period of moderately increased circulating antioxidative micronutrients and moderate doses of vitamin E with less concerns for potential adverse effects . In the present study, the experimental setting entails an expected demand for immediate available antioxidative response capacity due to the fast exposure to reactive oxygen species during inhalation of cigarette smoke. Effects of oral antioxidants is of particular interest with regard to the microvascular response in view of the reported low circulating levels of antioxidants in smokers [1,53,68], possibly reflecting increased consumption and thus a potential for beneficial replenishment.