Division of Kinesiology, School of Health and Human Performance, Faculty of Health, Dalhousie University, Halifax, Nova Scotia, Canada.
Division of Kinesiology, School of Health and Human Performance, Faculty of Health, Dalhousie University, Halifax, Nova Scotia, Canada.
Exp Gerontol. 2021 Mar;145:111221. doi: 10.1016/j.exger.2020.111221. Epub 2020 Dec 30.
Lower-limb arteries, such as the popliteal artery, are a common site of atherosclerosis. These arteries are habitually exposed to large fluctuations in blood flow during physical and sedentary activities. Low-flow-mediated constriction (L-FMC) and flow-mediated dilation (FMD) provide indices of endothelial-dependent vasoconstriction and vasodilation, respectively. Age and sex both impact upper-limb FMD. However, it is unclear whether these factors also influence popliteal endothelial-dependent function. Popliteal endothelial function was compared between younger and older males and females (n=14 per group) matched for age- and sex-specific relative aerobic fitness levels (each group's normative percentile: 45%). Nitroglycerin-mediated dilation (NMD) was also assessed as a measure of endothelial-independent vasodilation. Ageing reduced relative popliteal FMD in both males (older: 4.3±1.8% versus younger 5.7±1.9%) and females (older: 2.9±1.8% versus younger: 6.1±1.6%, both: P<0.046). FMD was also lower in older females versus older males (P=0.04). Popliteal NMD findings followed the same pattern as FMD. Compared to younger adults, relative L-FMC responses were blunted among older males (older: -1.2±1.1% versus younger: -2.2±1.0%) and females (older: -1.0±1.2% versus younger: -2.1±1.3%, both P<0.03) with no sex-differences observed in either age group (all, P>0.60). The adverse age- and sex-related (older adults only) declines in popliteal FMD were mediated, in part, by reduced vascular smooth muscle sensitivity to nitric oxide. Endothelial-dependent vasoconstriction was also attenuated with age, but unaffected by sex. Despite similar normative aerobic fitness percentiles (45%), older adults exhibited attenuated popliteal endothelial function than their younger counterparts. This was particularly evident in older females who exhibited the lowest endothelial-dependent vasodilatory responses.
下肢动脉，如腘动脉，是动脉粥样硬化的常见部位。这些动脉在体力活动和久坐不动时经常会经历血流的大幅波动。低流介导的收缩（L-FMC）和血流介导的扩张（FMD）分别提供了内皮依赖性血管收缩和扩张的指标。年龄和性别都会影响上肢 FMD。然而，目前尚不清楚这些因素是否也会影响腘动脉内皮依赖性功能。我们比较了年龄匹配的年轻和老年男性和女性（每组 14 人）的腘动脉内皮依赖性功能，这些人在年龄和性别特异性相对有氧健身水平上相匹配（每组的标准百分位数：45%）。还评估了硝酸甘油介导的扩张（NMD）作为内皮非依赖性血管扩张的指标。在男性（老年人：4.3±1.8%比年轻人：5.7±1.9%，均 P<0.046）和女性（老年人：2.9±1.8%比年轻人：6.1±1.6%，均 P<0.046）中，衰老都会降低相对腘动脉 FMD。与老年男性相比，老年女性的 FMD 也较低（P=0.04）。腘动脉 NMD 的发现与 FMD 相同。与年轻成年人相比，老年男性（老年人：-1.2±1.1%比年轻人：-2.2±1.0%）和女性（老年人：-1.0±1.2%比年轻人：-2.1±1.3%，均 P<0.03）的相对 L-FMC 反应较为迟钝，并且在任何一个年龄组中都没有观察到性别差异（均 P>0.60）。在老年人中，与年龄相关的不良变化（仅在老年人中）与一氧化氮引起的血管平滑肌敏感性降低有关。内皮依赖性血管收缩也随年龄而减弱，但不受性别影响。尽管具有相似的正常有氧健身百分位数（45%），但与年轻同龄人相比，老年人的腘动脉内皮功能减弱。这在老年女性中尤为明显，她们表现出最低的内皮依赖性血管舒张反应。
