Human Vascular Physiology Laboratory, Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas.
Department of Surgery, University of North Texas Health Science Center, Fort Worth, Texas.
Am J Physiol Regul Integr Comp Physiol. 2022 May 1;322(5):R360-R367. doi: 10.1152/ajpregu.00336.2021. Epub 2022 Feb 24.
Nonpharmacological therapies that protect against endothelial ischemia-reperfusion injury (I/R) remain limited in aged adults. Acute heat exposure protects against endothelial I/R injury in young adults, but its efficacy has never been explored in aged adults. Therefore, we tested the hypothesis that acute heat exposure would prevent the attenuation of endothelium-dependent vasodilation after I/R injury in aged adults. Nine (2 men, 69 ± 8 yr) aged adults were exposed to a thermoneutral control condition or whole body passive heating (water-perfused suit) sufficient to increase body core temperature by 1.2°C. Experiments were separated by at least 7 days. Heat exposure was always performed first to time match the thermoneutral control condition. Endothelium-dependent vasodilation was assessed via flow-mediated dilation of the brachial artery before (pre-I/R) and after I/R injury (post-I/R), which was induced by 20 min of arm ischemia followed by 20 min of reperfusion. Flow-mediated dilation was reduced following I/R injury for the thermoneutral control condition (pre-I/R, 4.5 ± 2.9% vs. post-I/R, 0.9 ± 2.8%, < 0.01), but was well maintained with prior heat exposure (pre-I/R, 4.4 ± 2.8% vs. post-I/R, 3.5 ± 2.8%, = 0.5). Taken together, acute heat exposure protects against endothelial I/R injury in aged adults. These results highlight the therapeutic potential of heat therapy to prevent endothelial dysfunction associated with I/R injury in aged adults who are most at risk for an ischemic event.
非药物疗法可预防内皮细胞缺血再灌注损伤（I/R），但在老年人中应用受限。急性热暴露可预防年轻成年人的内皮细胞 I/R 损伤，但尚未在老年人中进行研究。因此，我们假设急性热暴露可预防老年人 I/R 损伤后内皮依赖性血管舒张功能减弱。9 名（2 名男性，69±8 岁）老年人分别处于常温对照或全身被动加热（水灌注服）条件下，后者足以使核心体温升高 1.2°C。实验至少间隔 7 天。为了与常温对照条件相匹配，总是先进行热暴露。通过肱动脉血流介导的舒张来评估内皮依赖性血管舒张功能，在 I/R 损伤之前（I/R 前）和之后（I/R 后）进行，I/R 损伤通过 20 分钟的手臂缺血和 20 分钟的再灌注来诱导。在常温对照条件下，I/R 损伤后血流介导的舒张功能降低（I/R 前，4.5±2.9% vs. I/R 后，0.9±2.8%，<0.01），但在热暴露之前可得到良好维持（I/R 前，4.4±2.8% vs. I/R 后，3.5±2.8%，=0.5）。总之，急性热暴露可预防老年人的内皮细胞 I/R 损伤。这些结果突出了热疗预防与 I/R 损伤相关的内皮功能障碍的治疗潜力，I/R 损伤是老年人最易发生缺血事件的原因。
