Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX, USA.
Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
J Cereb Blood Flow Metab. 2020 Mar;40(3):600-610. doi: 10.1177/0271678X19828327. Epub 2019 Feb 15.
Age is the strongest risk factor for cerebrovascular disease; however, age-related changes in cerebrovascular function are still not well understood. The objective of this study was to measure cerebral vasomotor reactivity (CVMR) during hypo- and hypercapnia across the adult lifespan. One hundred fifty-three healthy participants (21-80 years) underwent measurements of cerebral blood flow velocity (CBFV) via transcranial Doppler, mean arterial pressure (MAP) via plethysmograph, and end-tidal CO (EtCO) via capnography during hyperventilation (hypocapnia) and a modified rebreathing protocol (hypercapnia). Cerebrovascular conductance (CVCi) and resistance (CVRi) indices were calculated from the ratios of CBFV and MAP. CVMRs were assessed by the slopes of CBFV and CVCi in response to changes in EtCO. The baseline CBFV and CVCi decreased and CVRi increased with age. Advanced age was associated with progressive declines in CVMR during hypocapnia indicating reduced cerebral vasoconstriction, but increases in CVMR during hypercapnia indicating increased vasodilation. A negative correlation between hypo- and hypercapnic CVMRs was observed across all subjects (CBFV%/ EtCO: = -0.419, CVCi%/ EtCO: = -0.442, < 0.0001). Collectively, these findings suggest that aging is associated with decreases in CBFV, increases in cerebrovascular resistance, reduced vasoconstriction during hypocapnia, but increased vasodilatory responsiveness during hypercapnia.
年龄是脑血管疾病的最强危险因素；然而，年龄相关的脑血管功能变化仍不清楚。本研究的目的是在成年期测量低碳酸血症和高碳酸血症期间的脑血管血流速度反应性（CVMR）。153 名健康参与者（21-80 岁）通过经颅多普勒测量脑血流速度（CBFV），通过体积描记法测量平均动脉压（MAP），通过二氧化碳描记法测量呼气末 CO（EtCO），在过度通气（低碳酸血症）和改良重呼吸协议（高碳酸血症）期间。从 CBFV 和 MAP 的比值计算脑血管传导率（CVCi）和阻力（CVRi）指数。通过 CBFV 和 CVCi 对 EtCO 变化的响应斜率评估 CVMR。基础 CBFV 和 CVCi 随年龄下降，CVRi 随年龄增加而增加。随着年龄的增长，CVMR 在低碳酸血症期间逐渐下降，表明大脑血管收缩减少，但在高碳酸血症期间增加，表明血管扩张增加。所有受试者的低碳酸血症和高碳酸血症 CVMR 呈负相关（CBFV%/EtCO：= -0.419，CVCi%/EtCO：= -0.442，<0.0001）。综上所述，这些发现表明，衰老与 CBFV 下降、脑血管阻力增加、低碳酸血症时血管收缩减少、高碳酸血症时血管扩张反应性增加有关。
