Document Detail


Acute and chronic angiotensin-1 receptor antagonism reverses endothelial dysfunction in atherosclerosis.
MedLine Citation:
PMID:  10821809     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: The renin-angiotensin system may contribute to atherogenesis through the promotion of endothelial dysfunction. The present study was performed to determine whether angiotensin-1 (AT(1)) receptor inhibition improves endothelial dysfunction. METHODS AND RESULTS: In the femoral circulation of 19 patients with atherosclerosis and of 9 control subjects, we studied microvascular responses to reactive hyperemia, angiotensin II, acetylcholine, and sodium nitroprusside before and after the administration of intra-arterial losartan (10 mg). Femoral artery flow velocity was measured with a Doppler flow wire, and the femoral vascular resistance index (FVRI) was calculated as mean arterial pressure divided by flow velocity. Losartan induced a minor (5.9+/-2%, P=0. 02) reduction in FVRI and inhibited angiotensin II-mediated vasoconstriction in both patient groups (P<0.01). After the administration of losartan, acetylcholine-mediated vasodilation was augmented in patients (44+/-5% to 58+/-4% reduction in FVRI with infusion at a rate of 150 microgram/min, P<0.001) but not control subjects. Vasodilation during reactive hyperemia was also greater after AT(1) receptor inhibition (P=0.03) in patients, but the response to sodium nitroprusside remained unchanged. In a separate group of 31 patients with atherosclerosis, we investigated the effect of 8 weeks of oral losartan therapy on brachial artery flow-mediated vasodilation with the use of high-resolution ultrasound. Oral losartan therapy improved flow-mediated brachial artery dilation (1.4+/-0.9% to 3.2+/-0.8%, P=0.03) but had no effect on the nitroglycerin response. Serum nitrogen oxide levels increased from 21.6+/-1.7 to 26.7+/-2.4 micromol/L (P=0.008). CONCLUSIONS: The results of the present study indicate that inhibition of the AT(1) receptor in patients with atherosclerosis reverses endothelial dysfunction by improving NO availability and therefore may have long-term therapeutic benefits.
Authors:
A Prasad; T Tupas-Habib; W H Schenke; R Mincemoyer; J A Panza; M A Waclawin; S Ellahham; A A Quyyumi
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Publication Detail:
Type:  Clinical Trial; Journal Article    
Journal Detail:
Title:  Circulation     Volume:  101     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2000 May 
Date Detail:
Created Date:  2000-06-21     Completed Date:  2000-06-21     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  2349-54     Citation Subset:  AIM; IM    
Affiliation:
Cardiology Branch, Office of Biostatistics Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
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MeSH Terms
Descriptor/Qualifier:
Acetylcholine / pharmacology
Angiotensin II / pharmacology
Arteriosclerosis / complications,  drug therapy*,  physiopathology
Brachial Artery / physiopathology
Endothelium, Vascular / drug effects*,  physiopathology
Female
Femoral Artery / physiopathology
Humans
Hyperemia / etiology,  physiopathology
Losartan / therapeutic use*
Male
Middle Aged
Nitroprusside / pharmacology
Receptor, Angiotensin, Type 1
Receptor, Angiotensin, Type 2
Receptors, Angiotensin / antagonists & inhibitors*
Regional Blood Flow / drug effects
Single-Blind Method
Time Factors
Vascular Resistance / drug effects
Vasodilation / drug effects
Vasodilator Agents / pharmacology
Chemical
Reg. No./Substance:
0/Receptor, Angiotensin, Type 1; 0/Receptor, Angiotensin, Type 2; 0/Receptors, Angiotensin; 0/Vasodilator Agents; 11128-99-7/Angiotensin II; 114798-26-4/Losartan; 15078-28-1/Nitroprusside; 51-84-3/Acetylcholine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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