* Department of Geriatric Medicine (925), Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
Exp Physiol. 2014 Mar;99(3):586-98. doi: 10.1113/expphysiol.2013.076455. Epub 2013 Dec 20.
With ageing, cerebral blood flow velocity (CBFV) decreases; however, to what extent dynamic cerebral autoregulation and cerebrovascular CO2 reactivity are influenced by ageing is unknown. The aim was to examine the dynamic responses of CBFV and cortical oxygenation to changes in blood pressure (BP) and arterial CO2 across different ages. Fifty-eight participants in three age groups were included, as follows: young (n = 20, 24 ± 2 years old), elderly (n = 20, 66 ± 1 years old), and older elderly (n = 18, 78 ± 3 years old). The CBFV was measured using transcranial Doppler ultrasound, simultaneously with oxyhaemoglobin (O2Hb) using near-infrared spectroscopy and beat-to-beat BP measurements using Finapres. Postural manoeuvres were performed to induce haemodynamic fluctuations. Cerebrovascular CO2 reactivity was tested with hyperventilation and CO2 inhalation. With age, CBFV decreased (young 59 ± 12 cm s(-1), elderly 48 ± 7 cm s(-1) and older elderly 42 ± 9 cm s(-1), P < 0.05) and cerebrovascular resistance increased (1.46 ± 0.58, 1.81 ± 0.36 and 1.98 ± 0.52 mmHg cm(-1) s(-1), respectively, P < 0.05). Normalized gain (autoregulatory damping) increased with age for BP-CBFV (0.88 ± 0.18, 1.31 ± 0.30 and 1.06 ± 0.34, respectively, P < 0.05) and CBFV-O2Hb (0.10 ± 0.09, 0.12 ± 0.04 and 0.17 ± 0.08, respectively, P < 0.05) during the repeated sit-stand manoeuvre at 0.05 Hz. Even though the absolute changes in CBFV and cerebrovascular resistance index during the cerebrovascular CO2 reactivity were higher in the young group, the percentage changes in CBFV, cerebrovascular resistance index and O2Hb were similar in all age groups. In conclusion, there was no decline in dynamic cerebral autoregulation and cerebrovascular CO2 reactivity with increasing age up to 86 years. Despite the decrease in cerebral blood flow velocity and increase in cerebrovascular resistance with advancing age, CBFV and cortical oxygenation were not compromised in these elderly humans during manoeuvres that mimic daily life activities.
随着年龄的增长，大脑血流速度（CBFV）会下降；然而，动态脑自动调节和脑血管二氧化碳反应性受年龄影响的程度尚不清楚。目的是研究 CBFV 和皮质氧合在不同年龄时对血压（BP）和动脉二氧化碳变化的动态反应。将 58 名参与者分为三组：年轻组（n=20，24±2 岁）、老年组（n=20，66±1 岁）和老年老年组（n=18，78±3 岁）。使用经颅多普勒超声测量 CBFV，同时使用近红外光谱测量氧合血红蛋白（O2Hb），使用 Finapres 测量逐搏血压。进行体位操作以诱导血液动力学波动。通过过度通气和二氧化碳吸入测试脑血管二氧化碳反应性。随着年龄的增长，CBFV 下降（年轻组 59±12cm/s，老年组 48±7cm/s，老年老年组 42±9cm/s，P<0.05），脑血管阻力增加（分别为 1.46±0.58、1.81±0.36 和 1.98±0.52mmHg·cm-1·s-1，P<0.05）。归一化增益（自动调节阻尼）随年龄增加而增加，用于 BP-CBFV（分别为 0.88±0.18、1.31±0.30 和 1.06±0.34，P<0.05）和 CBFV-O2Hb（分别为 0.10±0.09、0.12±0.04 和 0.17±0.08，P<0.05）在 0.05Hz 的重复坐站操作期间。尽管在年轻组中，CBFV 和脑血管阻力指数在脑血管二氧化碳反应性期间的绝对变化较高，但在所有年龄组中，CBFV、脑血管阻力指数和 O2Hb 的百分比变化相似。结论：在 86 岁之前，年龄的增加并没有导致动态脑自动调节和脑血管二氧化碳反应性的下降。尽管随着年龄的增长，大脑血流速度下降，脑血管阻力增加，但在这些老年人进行模拟日常生活活动的操作时，CBFV 和皮质氧合并未受到影响。
