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Aortic stiffness is associated with changes in retinal arteriole flow pulsatility mediated by local vasodilation in healthy young/middle-age adults.

Authors
  • Holwerda, Seth W1, 2, 3
  • Kardon, Randy H4, 5, 6
  • Hashimoto, Ryuya6
  • Full, Jan M6
  • Nellis, Julie K6
  • DuBose, Lyndsey E7
  • Fiedorowicz, Jess G2, 8, 9, 10
  • Pierce, Gary L1, 2
  • 1 Department of Health and Human Physiology, University of Iowa, Iowa City, Iowa.
  • 2 Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.
  • 3 Department of Anesthesiology, University of Kansas Medical Center, Kansas City, Kansas.
  • 4 Iowa City Veterans Affairs Center for Prevention and Treatment of Visual Loss, Iowa City, Iowa.
  • 5 Department of Veteran Affairs Hospital Iowa City, Iowa City, Iowa.
  • 6 Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa.
  • 7 Division of Geriatric Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado.
  • 8 Department of Psychiatry, University of Iowa, Iowa City, Iowa.
  • 9 Department of Epidemiology, University of Iowa, Iowa City, Iowa.
  • 10 Department of Internal Medicine, University of Iowa, Iowa City, Iowa.
Type
Published Article
Journal
Journal of Applied Physiology
Publisher
American Physiological Society
Publication Date
Jul 01, 2020
Volume
129
Issue
1
Pages
84–93
Identifiers
DOI: 10.1152/japplphysiol.00252.2020
PMID: 32437246
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

Aortic stiffness is associated with augmented pressure pulsatility in large conduit arteries and remodeling of the microcirculation. However, studies in humans examining the relation between aortic stiffness and end-organ microvascular flow pulsatility are limited. Therefore, we used the retinal microvasculature as an end-organ in vivo model to examine the hypothesis that aortic stiffness would be positively associated with microvascular flow pulsatility index (PI) (flow pulse amplitude/mean flow) in humans. In 40 young/middle-age healthy adults (25-60 yr old, 50% women), aortic stiffness (carotid-femoral pulse wave velocity, CFPWV) and retinal arteriole flow (laser speckle flowgraphy) were examined at rest and during metabolic vasodilation (light flicker). CFPWV and related increases in central pulse pressure (PP) were inversely correlated with arteriole lumen diameter independent of age (CFPWV: R = -0.52, P = 0.001; Central PP: R = -0.39, P = 0.014). Accordingly, microvascular resistance was positively related to CFPWV independent of age (R = 0.35, P = 0.031). Multiple linear regression showed that CFPWV was not a significant determinant of resting arteriole flow PI (β = -0.10, P = 0.64). However, during reduced retinal microvascular resistance using light flicker (P < 0.001), CFPWV was a significant determinant of the percent change in arteriole flow PI (β = 0.58, P = 0.046), but not mean flow (β = -0.17, P = 0.54), where reductions in arteriole flow PI were associated with lower CFPWV. In summary, our findings suggest that higher aortic stiffness and the related increase in central PP in healthy young/middle-age adults are associated with retinal arteriole narrowing and smaller reductions in arteriole flow pulsatility in response to dynamic conditions such as local metabolic vasodilation.NEW & NOTEWORTHY By using the human retinal microvasculature as an end-organ in vivo model, we confirm that aortic stiffness and related increases in central pulse pressure are inversely correlated with retinal arteriole lumen diameter and increased microvascular resistance among heathy young/middle-age adults. Additionally, higher aortic stiffness is not associated with excessive flow pulsatility in the retinal microvasculature under tonic conditions but may be related to limited reductions in retinal arteriole flow pulsatility in response to local vasodilation.

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