Frequent-Episodic Alcohol Consumption Impairs Macro-and Microvascular Function in Young Adults
thesisposted on 2012-12-13, 00:00 authored by Melissa M. Goslawski
Introduction: Previous studies have shown that individuals who engage in binge drinking (≥5 alcohol drinks/ 2 hours: men; ≥4 alcohol drinks/2 hours: women) at least once every two weeks have similar negative cardiovascular risk profiles as chronic drinkers. Altered vasoreactivity to dilator and constrictor stimuli may contribute to the negative effects of alcohol consumption on cardiovascular health. Therefore, the objective of this study was to test the hypothesis that binge drinking impairs brachial artery flow- mediated dilation (FMD) and vasoactive responses of resistance arteries to constrictor (endothelin-1; ET-I) and dilator(acetylcholine; ACh, sodium nitroprusside; SNP). Methods: Young men and women (mean age 25 years) who were abstainers (A; n=19) and those that reported binge drinking (n=17) were studied. Ultrasonography was used to determine brachial artery flow-mediated (endothelium- dependent [ED] vasodilation) and endothelium-independent [EI] vasodilation to nitroglycerin (NTG, 0.4 mg). To evaluate vascular reactivity to vascular derived substances, gluteal fat biopsies were obtained and resistance arterioles were isolated. Videomicroscopy was used to measure resistance arteriole diameter in the presence and absence of ACh (10-9 to 10-4 M), SNP (10-9 to 10-4 M) and ET-1 (10-11 to 10-8 M). Results: All groups were normocholesterolemic and normotensive. Brachial FMD (p=0.022) and NTG dilation (p=0.009) were significantly lower in binge drinkers compared to abstainers. In resistance arterioles, ACh dilations were similar in binge drinkers compared to abstainers. The nitric oxide synthase inhibitor L-NAME reduced ACh- dilations in abstainers (p=0.007) but not in BD. There was no effect of binge drinking SNP dilations in resistance arterioles. In contrast, constrictor responses to ET-1 was enhanced in binge drinkers compared to abstainers (p=0.002). Conclusions: These results suggest that binge drinking leads to 1) impaired ED and EI dilation in the brachial artery; 2) nitric oxide-mediated vasodilation in resistance arterioles of abstainers but not binge drinkers and 3) enhanced constriction in resistance arterioles of binge drinkers.