Washio Takuro, Sasaki Hiroyuki, Ogoh Shigehiko
Department of Biomedical Engineering, Toyo University, Kawagoe, Saitama, Japan.
Physiol Rep. 2017 May;5(10):e13288. doi: 10.14814/phy2.13288.
Previous studies have suggested that the risk of ischemic stroke increases immediately after drinking coffee. Indeed, drinking coffee, that is, caffeine, acutely increases arterial stiffness as well as blood pressure and peripheral vascular resistance. On the other hand, it has been reported that arterial stiffening is associated with elevation in the pulsatility index (PI) of cerebral blood flow (CBF), which increases the risk of brain disease. However, the effect of drinking coffee on the PI of the CBF and its interaction with arterial stiffness remain unknown. Against this background, we hypothesized that an acute increase in arterial stiffness induced by drinking coffee augments cerebral pulsatile stress. To test this hypothesis, in 10 healthy young men we examined the effects of drinking coffee on the PI of middle cerebral artery blood velocity (MCAv) and brachial-ankle pulse wave velocity (baPWV) as indices of cerebral pulsatile stress and arterial stiffness, respectively. Mean arterial blood pressure and baPWV were higher ( < 0.01 and = 0.02), whereas mean MCA and mean cerebrovascular conductance index were lower upon drinking coffee ( = 0.02 and < 0.01) compared with a placebo (decaffeinated coffee). However, there was no difference in the PI of MCAv between drinking coffee and the placebo condition. These findings suggest that drinking coffee does not increase cerebral pulsatile stress acutely despite an elevation in arterial stiffness in the systemic circulation.
以往的研究表明，饮用咖啡后缺血性中风的风险会立即增加。事实上，饮用咖啡，即摄入咖啡因，会急性增加动脉僵硬度以及血压和外周血管阻力。另一方面，据报道动脉僵硬度与脑血流（CBF）搏动指数（PI）升高有关，这会增加脑部疾病的风险。然而，饮用咖啡对CBF的PI的影响及其与动脉僵硬度的相互作用仍不清楚。在此背景下，我们假设饮用咖啡引起的动脉僵硬度急性增加会增强脑搏动应力。为了验证这一假设，我们对10名健康年轻男性进行了研究，分别以大脑中动脉血流速度（MCAv）的PI和臂踝脉搏波速度（baPWV）作为脑搏动应力和动脉僵硬度的指标，检测饮用咖啡对它们的影响。与安慰剂（脱咖啡因咖啡）相比，饮用咖啡后平均动脉血压和baPWV更高（<0.01和=0.02），而平均MCA和平均脑血管传导指数更低（=0.02和<0.01）。然而，饮用咖啡与安慰剂条件下MCAv的PI没有差异。这些发现表明，尽管体循环中的动脉僵硬度升高，但饮用咖啡并不会急性增加脑搏动应力。
