Journal article
Hypercapnia-induced shear-mediated dilation in the internal carotid artery is blunted in healthy older adults
American journal of physiology. Heart and circulatory physiology, Vol.315(5), pp.H1279-H1286
11/01/2018
DOI: 10.1152/ajpheart.00335.2018
PMID: 30118339
Abstract
This study aimed to elucidate the effect of aging on shear-mediated dilation of the common and internal carotid arteries (CCA and ICA, respectively). Hypercapnia-induced shear-mediated dilation in the CCA and ICA were assessed in 10 young (5 women and 5 men, 23 ± 1 yr) and 10 older (6 women/4 men, 68 ± 1 yr) healthy adults. Shear-mediated dilation was induced by two levels of hypercapnia (target end-tidal Pco2, +5 and +10 mmHg from individual baseline values) and was calculated as the percent rise in peak diameter from baseline diameter. There were no differences in shear-mediated dilation between young and older adults in either artery under lower levels of hypercapnia (CCA: 2.8 ± 0.6 vs. 2.0 ± 0.3%, P = 0.35; ICA: 4.6 ± 0.8 vs 3.6 ± 0.4%, P = 0.37). However, shear-mediated dilation in response to higher levels of hypercapnia was attenuated in older compared with young adults in the ICA (4.5 ± 0.5 vs. 7.9 ± 1.2%, P < 0.01) but not in the CCA (3.7 ± 0.6 vs. 4.5 ± 0.8%, P = 0.35). Shear-mediated dilation was significantly correlated to the percent change in shear rate in the ICA (young: r = 0.55, P = 0.01; older: r = 0.49, P = 0.03) but not in the CCA in either young or older adults (young: r = −0.30, P = 0.90; older: r = 0.16, P = 0.50). These data indicate that aging attenuates shear-mediated dilation of the ICA in response to higher levels of hypercapnia, and shear rate is an important stimulus for hypercapnic vasodilation of the ICA in both young and older adults. The present results may provide insights into age-related changes in the regulation of cerebral circulation in healthy adults. NEW & NOTEWORTHY We explored the effect of aging on shear-mediated dilation in the common and internal carotid arteries (CCA and ICA, respectively) in healthy adults. Our findings suggest that 1) aging attenuates shear-mediated dilation of the ICA but not the CCA and 2) shear rate is an important stimulus for hypercapnic vasodilation of the ICA in young and older adults. These findings may provide insights into the age-related changes in cerebrovascular regulation of healthy adults.
Details
- Title: Subtitle
- Hypercapnia-induced shear-mediated dilation in the internal carotid artery is blunted in healthy older adults
- Creators
- Erika Iwamoto - Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa, School of Health Sciences, Sapporo Medical University, Sapporo, JapanJoshua M Bock - Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IowaDarren P Casey - Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa, Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa, Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa
- Resource Type
- Journal article
- Publication Details
- American journal of physiology. Heart and circulatory physiology, Vol.315(5), pp.H1279-H1286
- DOI
- 10.1152/ajpheart.00335.2018
- PMID
- 30118339
- NLM abbreviation
- Am J Physiol Heart Circ Physiol
- ISSN
- 0363-6135
- eISSN
- 1522-1539
- Language
- English
- Date published
- 11/01/2018
- Academic Unit
- Physical Therapy and Rehabilitation Science; Fraternal Order of Eagles Diabetes Research Center
- Record Identifier
- 9984046925902771
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