Acute limb heating improves macro-and microvascular dilator function in the leg of aged humans
Acute limb heating improves macro-and microvascular dilator function in the leg of aged humans
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DOI：
10.1152/ajpheart.00519.2016
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发表时间：
2017-01-01
影响因子：
4.8
通讯作者：
Crandall, Craig G.
中科院分区：
文献类型：
--
作者：
Romero, Steven A.;Gagnon, Daniel;Crandall, Craig G.
肢体局部加热会增加整个动脉树的血流量和血管剪切应力。局部加热通过剪切应力依赖机制显著改善健康青年上肢的大血管扩张功能，但对该年龄组的下肢无此作用。急性肢体加热对老年人下肢动脉粥样硬化血管扩张功能的影响尚不清楚。因此，本研究的目的是验证急性下肢加热改善老年人腿部血管内大血管和微血管扩张功能的假设。九名年轻人和九名老年人将他们的下肢浸在大约33厘米深的温水（大约42摄氏度）循环水浴中45分钟。加热前和加热后30分钟，在动脉闭塞5分钟后，通过多普勒超声评估下肢宏观（血流介导的扩张）和微血管（反应性充血）扩张功能。与预热相比，年轻人加热后大血管扩张功能没有变化（P = 0.6），而老年人加热后大血管扩张功能有所改善（P = 0.04）。同样，通过峰值反应性充血来评估的微血管扩张功能，在年轻人中加热后没有变化（P = 0.1），但在老年人中有所改善（P < 0.01）。综上所述，这些数据表明急性下肢加热以年龄依赖的方式改善宏观和微血管扩张功能。新的和值得注意的是，我们证明，下肢加热可以显著改善老年人腿部动脉粥样硬化易发血管中的大血管和微血管扩张功能。这些发现为慢性下肢加热在原发性衰老和各种疾病条件下改善血管健康的潜在治疗用途提供了证据。
Local heating of an extremity increases blood flow and vascular shear stress throughout the arterial tree. Local heating acutely improves macrovascular dilator function in the upper limbs of young healthy adults through a shear stress-dependent mechanism but has no such effect in the lower limbs of this age group. The effect of acute limb heating on dilator function within the atherosclerotic prone vasculature of the lower limbs of aged adults is unknown. Therefore, the purpose of this study was to test the hypothesis that acute lower limb heating improves macro-and microvascular dilator function within the leg vasculature of aged adults. Nine young and nine aged adults immersed their lower limbs at a depth of similar to 33 cm into a heated (similar to 42 degrees C) circulated water bath for 45 min. Before and 30 min after heating, macro (flow-mediated dilation)and microvascular (reactive hyperemia) dilator functions were assessed in the lower limb, following 5 min of arterial occlusion, via Doppler ultrasound. Compared with preheat, macrovascular dilator function was unchanged following heating in young adults (P = 0.6) but was improved in aged adults (P = 0.04). Similarly, microvascular dilator function, as assessed by peak reactive hyperemia, was unchanged following heating in young adults (P = 0.1) but was improved in aged adults (P < 0.01). Taken together, these data suggest that acute lower limb heating improves both macro-and microvascular dilator function in an age dependent manner.NEW & NOTEWORTHY We demonstrate that lower limb heating acutely improves macro- and microvascular dilator function within the atherosclerotic prone vasculature of the leg in aged adults. These findings provide evidence for a potential therapeutic use of chronic lower limb heating to improve vascular health in primary aging and various disease conditions.