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Aim:To compare the acute effects of ascorbic acid on vasodilation of veins andarteries in vivo.Methods:Twenty-six healthy non-smokers and 23 healthy moder-ate smokers were recruited in this study.The dorsal hand vein compliance tech-nique and flow-mediated dilation were used.Dose-response curves to bradykininand sodium nitroprusside were constructed to test the endothelium-dependentand-independent relaxation before and after acute infusion of ascorbic acid.Results:Smokers had an impaired venodilation with bradykinin compared withnon-smokers(68.3%±13.2% vs 93.7%±20.1%,respectively;P<0.05).Ascorbic acidadministration in the dorsal hand vein significantly increased the venodilationwith bradykinin in smokers(68.3%±13.2% vs 89.5%±6.3% before and after infusion,respectively;P<0.05)but not in non-smokers(93.7%±20.1% vs 86.4%±12.4% be-fore and after infusion,respectively).Similarly,the arterial response in smokershad an impaired endothelium-dependent dilation compared with that in non-smok-ers(8.8%±2.7% vs 15.2%±2.3%,respectively;P<0.05)and ascorbic acid restoredthis response in smokers(8.8%±2.7% vs 18.7%±6.5% before and after infusion,respectively;P<0.05),but no difference was seen in non-smokers(15.2%±2.3% vs14.0%±4.4% before and after infusion,respectively).The endothelium-indepen-dent dilation did not differ in both the groups studied.No important hemody-namic change was detected using the Portapress device.Conclusion:Smokershad impaired endothelium-dependent vasodilation responsiveness in both arte-rial and venous systems.Ascorbic acid restores this responsiveness in smokers.
Aim: To compare the acute effects of ascorbic acid on vasodilation of veins and arteries in vivo. Methods: Twenty-six healthy non-smokers and 23 healthy moder-ate smokers were recruited in this study. Dorsal hand vein compliance tech-nique and flow -mediated dilation were used. Dose-response curves to bradykinin and sodium nitroprusside were constructed to test the endothelium-dependent and-independent relaxation before and after acute infusion of ascorbic acid. Results: Smokers had an impaired venodilation with bradykinin compared with non-smokers (68.3% ± 13.2% vs 93.7% ± 20.1%, respectively; P <0.05) .Ascorbic acid administration in the dorsal hand vein significantly increased the venodilation with bradykinin in smokers (68.3% ± 13.2% vs 89.5% ± 6.3% before and after infusion, respectively; Respectively, the arterial response in smokershad an impaired endothelium-dependent dilation compared with that in non-smokers (93.7% ± 20.1% vs 86.4% ± 12.4% be-fore and after infusion, respectively) -sm (8.8% ± 2.7% vs 15.2% ± 2.3%, respectively; P <0.05) and ascorbic acid restored in response to smokers (8.8% ± 2.7% vs 18.7% ± 6.5% before and after infusion, respectively; P < 0.05), but no difference was seen in non-smokers (15.2% ± 2.3% vs 14.0% ± 4.4% before and after infusion, respectively). The endothelium-indepen-dent dilation did not differ in both the groups studied. important hemody-namic change was detected using the Portapress device. Confc: Smokershad impaired endothelium-dependent vasodilation responsiveness in both arte-rial and venous systems. Ascorbic acid restores this responsiveness in smokers.