Department of Neuroscience, Biomedicine, and Movement Sciences, University of Verona, Verona, Italy.
Italian Institute for Cardiovascular Research (INRC), Bologna, Italy.
Biol Sex Differ. 2022 Jun 25;13(1):33. doi: 10.1186/s13293-022-00444-0.
The in-vivo regulation of vascular conductance (VC) is a continuous balance between endothelial vasodilation and sympathetic vasoconstriction. Although women may report blunted sympathetic vasoconstriction along with higher endothelial vasodilation than men, it is currently unknown whether the interaction between vasoconstriction and vasodilation leads to different regulation of VC between sexes. This study assessed sex differences in sympathetic-mediated blunting of endothelial vasodilation after a brief period of ischemia and whether any restriction of vasodilation blunts tissue blood flow (BF) and re-oxygenation.
13 young women and 12 young men underwent two 5-min forearm circulatory occlusions followed by reperfusion, one in basal conditions and the other during cold pressor test-induced sympathetic activation (SYMP). Brachial artery diameter and BF, mean arterial pressure, total peripheral resistance (TPR), and thenar eminence oxygenation were collected. Percent changes normalized to baseline values of forearm VC, brachial artery BF and flow-mediated dilation (FMD), TPR, and hand oxygenation after circulatory reperfusion were calculated.
TPR increased during SYMP in men (p = 0.019) but not in women (p = 0.967). Women showed a greater brachial artery FMD than men (p = 0.004) at rest, but sex differences disappeared after normalization to shear rate and baseline diameter (p > 0.11). The percent increases from baseline of peak and average forearm VC after circulatory reperfusion did not differ between sexes in basal conditions (p > 0.98) or during SYMP (p > 0.97), and were restrained by SYMP similarly in both sexes (p < 0.003) without impairing the hand re-oxygenation (p > 0.08) or average hyperemic response (p > 0.09).
Although women may report blunted sympathetic vasoconstriction than men when assessed separately, the similar sympathetic-mediated restriction of vasodilation suggests a similar dynamic regulation of VC between sexes. SYMP-mediated restrictions of the normal forearm vasodilation do not impair the average hyperemic response and hand re-oxygenation in both sexes.
血管传导（VC）的体内调节是内皮舒张和交感缩血管之间的持续平衡。尽管女性可能报告说交感缩血管作用减弱，内皮舒张作用增强，但目前尚不清楚血管收缩和舒张之间的相互作用是否会导致两性之间 VC 的不同调节。本研究评估了短暂缺血后交感介导的内皮舒张功能减弱的性别差异，以及任何血管舒张受限是否会减弱组织血流（BF）和再氧合。
13 名年轻女性和 12 名年轻男性接受了两次 5 分钟的前臂循环闭塞，随后再灌注，一次在基础条件下，另一次在冷加压试验诱导的交感激活（SYMP）期间。采集肱动脉直径和 BF、平均动脉压、总外周阻力（TPR）和鱼际氧合。计算前臂 VC、肱动脉 BF 和血流介导的扩张（FMD）、TPR 和再灌注后手部氧合的基础值归一化后的百分比变化。
在 SYMP 期间，男性的 TPR 增加（p = 0.019），而女性则没有（p = 0.967）。女性在休息时的肱动脉 FMD 大于男性（p = 0.004），但在归一化至剪切率和基础直径后，性别差异消失（p > 0.11）。在基础条件下（p > 0.98）或在 SYMP 期间（p > 0.97），循环再灌注后峰值和平均前臂 VC 从基础值的百分比增加在两性之间没有差异，并且在两性中 SYMP 同样限制了血管舒张（p < 0.003），而不损害手部再氧合（p > 0.08）或平均充血反应（p > 0.09）。
尽管女性在单独评估时可能报告说交感缩血管作用比男性减弱，但相似的交感介导的血管舒张限制表明两性之间 VC 的调节相似。SYMP 介导的正常前臂血管舒张受限不会损害两性的平均充血反应和手部再氧合。
Zotero 插件
