Impact of aging on conduit artery retrograde and oscillatory shear at rest and during exercise: Role of nitric oxide

Jaume Padilla, Grant H. Simmons, Paul J. Fadel, M. Harold Laughlin, Michael Joseph Joyner, Darren P. Casey

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

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-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 and 0.11±.0.02 arbitrary units, respectively) compared with young subjects (-4.8±2.3 s 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.

Original languageEnglish (US)
Pages (from-to)484-489
Number of pages6
JournalHypertension
Volume57
Issue number3
DOIs
StatePublished - Mar 2011

Fingerprint

Nitric Oxide
Brachial Artery
Arteries
Exercise
Forearm
Nitric Oxide Synthase
Biological Availability
Doppler Ultrasonography
Muscle Contraction
Arginine
Healthy Volunteers
Endothelial Cells
Hemodynamics
Phenotype

Keywords

  • age
  • nitric oxide bioavailability
  • oscillatory shear stress
  • retrograde shear stress
  • vascular conductance

ASJC Scopus subject areas

  • Internal Medicine

Cite this

Impact of aging on conduit artery retrograde and oscillatory shear at rest and during exercise : Role of nitric oxide. / Padilla, Jaume; Simmons, Grant H.; Fadel, Paul J.; Laughlin, M. Harold; Joyner, Michael Joseph; Casey, Darren P.

In: Hypertension, Vol. 57, No. 3, 03.2011, p. 484-489.

Research output: Contribution to journalArticle

Padilla, Jaume ; Simmons, Grant H. ; Fadel, Paul J. ; Laughlin, M. Harold ; Joyner, Michael Joseph ; Casey, Darren P. / Impact of aging on conduit artery retrograde and oscillatory shear at rest and during exercise : Role of nitric oxide. In: Hypertension. 2011 ; Vol. 57, No. 3. pp. 484-489.
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