Document Detail


Impact of aging on conduit artery retrograde and oscillatory shear at rest and during exercise: role of nitric oxide.
MedLine Citation:
PMID:  21263118     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Aging has been recently associated with increased retrograde and oscillatory shear in peripheral conduit arteries, a hemodynamic environment that favors a proatherogenic endothelial cell phenotype. We evaluated whether nitric oxide (NO) bioavailability in resistance vessels contributes to age-related differences in shear rate patterns in upstream conduit arteries at rest and during rhythmic muscle contraction. Younger (n=11, age 26 ± 2 years) and older (n=11, age 61 ± 2 years) healthy subjects received intra-arterial saline (control) and the NO synthase inhibitor N(G)-Monomethyl-L-arginine. Brachial artery diameter and velocities were measured via Doppler ultrasound at rest and during a 5-minute bout of rhythmic forearm exercise. At rest, older subjects exhibited greater brachial artery retrograde and oscillatory shear (-13.2 ± 3.0 s(-1) and 0.11 ± .0.02 arbitrary units, respectively) compared with young subjects (-4.8 ± 2.3 s(-1) and 0.04 ± 0.02 arbitrary units, respectively; both P<0.05). NO synthase inhibition in the forearm circulation of young, but not of older, subjects increased retrograde and oscillatory shear (both P<0.05), such that differences between young and old at rest were abolished (both P>0.05). From rest to steady-state exercise, older subjects decreased retrograde and oscillatory shear (both P<0.05) to the extent that no exercise-related differences were found between groups (both P>0.05). Inhibition of NO synthase in the forearm circulation did not affect retrograde and oscillatory shear during exercise in either group (all P>0.05). These data demonstrate for the first time that reduced NO bioavailability in the resistance vessels contributes, in part, to age-related discrepancies in resting shear patterns, thus identifying a potential mechanism for increased risk of atherosclerotic disease in conduit arteries.
Authors:
Jaume Padilla; Grant H Simmons; Paul J Fadel; M Harold Laughlin; Michael J Joyner; Darren P Casey
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2011-01-24
Journal Detail:
Title:  Hypertension     Volume:  57     ISSN:  1524-4563     ISO Abbreviation:  Hypertension     Publication Date:  2011 Mar 
Date Detail:
Created Date:  2011-02-17     Completed Date:  2011-04-14     Revised Date:  2012-03-07    
Medline Journal Info:
Nlm Unique ID:  7906255     Medline TA:  Hypertension     Country:  United States    
Other Details:
Languages:  eng     Pagination:  484-9     Citation Subset:  IM    
Affiliation:
Department of Biomedical Sciences, University of Missouri, Columbia, MO 65211, USA. padillaja@missouri.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Age Factors
Aged
Aging / physiology*
Analysis of Variance
Blood Flow Velocity / drug effects,  physiology
Brachial Artery / drug effects,  physiology*,  ultrasonography
Enzyme Inhibitors / pharmacology
Exercise / physiology*
Humans
Middle Aged
Nitric Oxide / physiology*
Nitric Oxide Synthase / antagonists & inhibitors
Regional Blood Flow / physiology
omega-N-Methylarginine / pharmacology
Grant Support
ID/Acronym/Agency:
AR-55819/AR/NIAMS NIH HHS; F32 AR055819-01A1/AR/NIAMS NIH HHS; HL-093167/HL/NHLBI NIH HHS; HL-46493/HL/NHLBI NIH HHS; R01 HL036088-24/HL/NHLBI NIH HHS; R01 HL036088-25/HL/NHLBI NIH HHS; R01 HL046493-08/HL/NHLBI NIH HHS; R01 HL093167-01S1/HL/NHLBI NIH HHS; R01 HL093167-04/HL/NHLBI NIH HHS; RR-024150/RR/NCRR NIH HHS; T32-AR048523/AR/NIAMS NIH HHS
Chemical
Reg. No./Substance:
0/Enzyme Inhibitors; 10102-43-9/Nitric Oxide; 17035-90-4/omega-N-Methylarginine; EC 1.14.13.39/Nitric Oxide Synthase

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