高碳酸血症诱导的颈内动脉剪切介导扩张在健康老年人中减弱。
Hypercapnia-induced shear-mediated dilation in the internal carotid artery is blunted in healthy older adults.
机构信息
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 , Japan.
出版信息
Am J Physiol Heart Circ Physiol. 2018 Nov 1;315(5):H1279-H1286. doi: 10.1152/ajpheart.00335.2018. Epub 2018 Aug 17.
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 Pco, +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.
本研究旨在阐明衰老对颈总动脉（CCA）和颈内动脉（ICA）剪切介导扩张的影响。在 10 名年轻（女性 5 名，男性 5 名，23 ± 1 岁）和 10 名老年（女性 6 名，男性 4 名，68 ± 1 岁）健康成年人中，评估了高碳酸血症诱导的 CCA 和 ICA 的剪切介导扩张。通过两种水平的高碳酸血症（目标呼气末 Pco2 比个体基础值分别增加+5 和+10 mmHg）诱导剪切介导扩张，并计算为峰直径相对于基线直径的上升百分比。在较低水平的高碳酸血症下，年轻和老年成年人的动脉之间的剪切介导扩张没有差异（CCA：2.8 ± 0.6%对 2.0 ± 0.3%，P = 0.35；ICA：4.6 ± 0.8%对 3.6 ± 0.4%，P = 0.37）。然而，与年轻成年人相比，高碳酸血症时 ICA 的剪切介导扩张在老年成年人中减弱（4.5 ± 0.5%对 7.9 ± 1.2%，P < 0.01），但在 CCA 中没有（3.7 ± 0.6%对 4.5 ± 0.8%，P = 0.35）。ICA 中的剪切介导扩张与剪切率的变化百分比显著相关（年轻组：r = 0.55，P = 0.01；老年组：r = 0.49，P = 0.03），但在年轻或老年成年人的 CCA 中没有（年轻组：r = -0.30，P = 0.90；老年组：r = 0.16，P = 0.50）。这些数据表明，衰老会减弱高碳酸血症时 ICA 的剪切介导扩张，并且剪切率是年轻和老年成年人 ICA 高碳酸血症性血管扩张的重要刺激因素。本研究结果可能为健康成年人脑循环调节的年龄相关变化提供新的见解。新的和值得注意的是：我们探讨了衰老对健康成年人颈总动脉（CCA）和颈内动脉（ICA）剪切介导扩张的影响。我们的发现表明：1）衰老会减弱 ICA 的剪切介导扩张，但不会减弱 CCA；2）剪切率是年轻和老年成年人 ICA 高碳酸血症性血管扩张的重要刺激因素。这些发现可能为健康成年人脑血管调节的年龄相关变化提供新的见解。
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