Impairment of moment-to-moment adjustment of cerebral blood flow (CBF) to the increased oxygen and energy requirements of active brain regions via neurovascular coupling (NVC) contributes to the genesis of age-related cognitive impairment. Aging is associated with marked deficiency in the vasoprotective hormone insulin-like growth factor-1 (IGF-1). Preclinical studies on animal models of aging suggest that circulating IGF-1 deficiency is causally linked to impairment of NVC responses. The present study was designed to test the hypotheses that decreases in circulating IGF-1 levels in older adults also predict the magnitude of age-related decline of NVC responses. In a single-center cross-sectional study, we enrolled healthy young (n = 31, 11 female, 20 male, mean age: 28.4 + / − 4.2 years) and aged volunteers (n = 32, 18 female, 14 male, mean age: 67.9 + / − 4.1 years). Serum IGF-1 level, basal CBF (phase contrast magnetic resonance imaging (MRI)), and NVC responses during the trail making task (with transcranial Doppler sonography) were assessed. We found that circulating IGF-1 levels were significantly decreased with age and associated with decreased basal CBF. Age-related decline in IGF-1 levels predicted the magnitude of age-related decline in NVC responses. In conclusion, our study provides additional evidence in support of the concept that age-related circulating IGF-1 deficiency contributes to neurovascular aging, impairing CBF and functional hyperemia in older adults.

通过神经血管耦合（NVC），脑血流量（CBF）对活跃大脑区域增加的氧气和能量需求的即时调节受损，导致与年龄相关的认知障碍的发生。衰老与血管保护激素胰岛素样生长因子-1 (IGF-1) 的明显缺乏有关。对衰老动物模型的临床前研究表明，循环 IGF-1 缺乏与 NVC 反应受损存在因果关系。本研究旨在检验以下假设：老年人循环 IGF-1 水平的降低也可以预测 NVC 反应与年龄相关的下降程度。在一项单中心横断面研究中，我们招募了健康年轻人（n  = 31，其中 11 名女性，20 名男性，平均年龄：28.4 + / − 4.2 岁）和老年志愿者（n  = 32，18 名女性，14 名男性，平均年龄：年龄：67.9+/-4.1岁）。评估了试验过程中的血清 IGF-1 水平、基础 CBF（相衬磁共振成像 (MRI)）和 NVC 反应（使用经颅多普勒超声检查）。我们发现循环 IGF-1 水平随着年龄的增长而显着降低，并与基础 CBF 降低相关。IGF-1 水平与年龄相关的下降预示着 NVC 反应与年龄相关的下降程度。总之，我们的研究提供了额外的证据来支持这样的观点：年龄相关的循环 IGF-1 缺乏会导致老年人的神经血管老化、CBF 受损和功能性充血。