Abstract 16009: Frequent, Episodic Alcohol Consumption Alters Macro-and Micro-Vascular Reactivity in Young Adults
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 the 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 (RA) 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=15) and those that reported binge drinking (n=13) were studied. Binge drinkers (BD) were classified as recent BD (within 24-72 hrs of study enrollment) or late BD (more than 96 hours post a BD episode relative to study enrollment). Ultrasonography was used to determine brachial artery flow-mediated (endothelium- dependent [ED] vasodilation) and endothelium-independent [EID] vasodilation to nitroglycerin (NTG, 0.4 mg). To evaluate vascular reactivity to vascular derived substances, gluteal fat biopsies were obtained and RAs were isolated. Videomicroscopy was used to measure RA 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 was similar among the 3 groups. In contrast, NTG dilation tended to be lower in recent BD (12.5±3%) compared to late BD (19.5±3%) (p=.111). In RA, ACh dilations were reduced in BD compared to A (p=.028), regardless of time lapsed since binge drinking episode. The NOS inhibitor L-NAME reduced ACh- dilations in A (p=.071) but not in late BD or recent BD. There was no effect of binge drinking SNP dilations in RA. In contrast, constrictor responses to ET-1 tended to be enhanced in BD compared to A (p=.143). These results suggest that binge drinking 1) reduces NTG -mediated dilations in conduit arteries; 2) reduces ACh- dilations in resistance arteries; and 3) alters the mechanism of dilation to ACh in humans.
- © 2011 by American Heart Association, Inc.