The impact of menstrual phase on brachial artery flow-mediated dilatation during handgrip exercise in healthy premenopausal women
The impact of menstrual phase on brachial artery flow-mediated dilatation during handgrip exercise in healthy premenopausal women
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DOI：
10.1113/ep086311
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发表时间：
2018-02-01
影响因子：
2.7
通讯作者：
Pyke, Kyra E.
中科院分区：
文献类型：
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作者：
D'Urzo, Katrina A.;King, Trevor J.;Pyke, Kyra E.
新发现这项研究的中心问题是什么？本研究的目的是确定运动引起的剪应力持续增加时，月经时相对血流介导的血管扩张的影响。主要发现和重要性是什么？我们首次发现，在健康的绝经前女性中，运动引起的剪应力增加所刺激的血流介导的扩张不会在月经周期的两个阶段波动，尽管雌激素有显著的波动。这表明，在高雌激素阶段，内皮功能并不是持续增强的。血流介导的扩张(FMD)响应于持续的切应力刺激(例如，通过握手运动；HGEX)正在成为评估内皮功能的有用工具；然而，月经阶段对HGEX-FMD的影响尚不清楚。这项研究的目的是确定在月经周期的两个离散阶段(低雌激素和高雌激素)，HGEX-FMD是否随着雌激素浓度的周期性变化而波动。分别用二维超声和多普勒超声测量肱动脉内径和血流速度。用切变率(SR=BA血流速度/BA内径)估算切应力。参与者(12名健康、经常骑自行车的女性，21+/-2岁)完成了两次实验：(I)低雌激素(早期卵泡，EF)；(Ii)高雌激素(晚期卵泡，LF)。在每次访问中评估反应性充血刺激的FMD(RH-FMD)和HGEX-FMD(6min握力运动)。结果是平均值+/-SD。雌激素水平从EF期到LF期逐渐升高(EF，33+/-9pgml(-1)；LF，161+/-113pgml(-1)，P=0.003)。然而，SR刺激(HGEX，P=0.501；RH，P=0.173)和FMD反应在不同时相均无差异(EF和LF：HGEX-FMD4.8+/-2.8vs4.6+/-2.2%，P=0.601；RH-FMD7.9+/-4.3vs6.4+/-3.1%，P=0.071)。这些结果扩展了现有的RH-FMD发现，表明并不是所有的女性都会经历FMD随月经周期的波动。需要进一步的研究来研究月经期对FMD影响的可变性的机制。
New Findings What is the central question of this study? The aim of this study was to determine the influence of menstrual phase on flow-mediated dilatation in response to sustained, exercise-induced increases in shear stress.What is the main finding and its importance? We showed, for the first time, that in healthy, premenopausal women the flow-mediated dilatation stimulated by exercise-induced increases in shear stress did not fluctuate across two phases of the menstrual cycle, despite significant fluctuations in oestrogen. This suggests that endothelial function is not consistently augmented in the high-oestrogen phase.Flow-mediated dilatation (FMD) in response to a sustained shear-stress stimulus (e.g. via handgrip exercise; HGEX) is emerging as a useful tool for assessing endothelial function; however, the impact of menstrual phase on HGEX-FMD is unknown. The purpose of this study was to determine whether HGEX-FMD fluctuates with cyclical changes in oestrogen concentrations over two discrete phases (low and high oestrogen) of the menstrual cycle. Brachial artery (BA) diameter and blood velocity were assessed with two-dimesional and Doppler ultrasound, respectively. Shear stress was estimated using shear rate (SR=BA blood velocity/BA diameter). Participants (12 healthy, regularly cycling women, 21 +/- 2years of age) completed two experimental visits: (i) low oestrogen (early follicular, EF); and (ii) high oestrogen (late follicular, LF). Reactive hyperaemia-stimulated FMD (RH-FMD) and HGEX-FMD (6min of handgrip exercise) were assessed during each visit. Results are mean values +/- SD. Oestrogen increased from the EF to LF phase (EF, 33 +/- 9pgml(-1); LF, 161 +/- 113pgml(-1), P=0.003). However, neither the SR stimuli (HGEX, P=0.501; RH, P=0.173) nor the FMD responses differed between phases (EF versus LF: HGEX-FMD, 4.8 +/- 2.8 versus 4.6 +/- 2.2%, P=0.601; RH-FMD, 7.9 +/- 4.3 versus 6.4 +/- 3.1%, P=0.071). These results extend existing RH-FMD findings indicating that not all women experience fluctuations in FMD with the menstrual cycle. Further research is needed to investigate the mechanisms that underlie variability in the impact of menstrual phase on FMD.