Abstract: Objective To explore the pathogenesis of age?related white matter changes (ARWMC), and to investigate the correlation between ARWMC and the number of circulating endothelial progenitor cells (EPCs) and cognitive function in order to provide evidence for early prevention and treatment of ARWMC and cognitive impairment in elderly people. Methods Forty patients with ARWMC were confirmed by CT or MRI. The number of circulating EPCs was measured by flow cytometry. The cognitive function was evaluated by Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). One way analysis of variance (ANOVA) of completely random design and χ2 test of R × C tabular data were used to select single factor. Logistic regression (backward) was performed to determine the risk factors for ARWMC. Results Flow cytometry showed that the number of circulating EPCs reduced in patients with ARWMC, especially in severe group (29.50 ± 6.26), and there was statistically significant difference compared with control group (70.50 ± 8.71) and mild-to-moderate group (58.99 ± 7.78; P = 0.000, for all). The number of circulating EPCs was negatively correlated with the severity of ARWMC (r =-0.562, P = 0.001). The scores of MMSE (23.85 ± 2.35) and the scores of MoCA (19.80 ± 3.38) in severe group were significantly lower than control group (27.10 ± 1.80, 26.60 ± 1.23, respectively) and mild-to-moderate group (25.80 ± 2.02, 23.30 ± 2.87, respectively), and there was statistically significant difference between groups (P < 0.05, for all). Cognitive impairment was mainly presented on visuoconstructional and executive functions, delayed recall and orientation. Conclusion The change of the number of circulating EPCs can be a predictive factor for ARWMC, and it is a potential predictor of the severity of ARWMC. The decrease of the circulating EPCs may be an important pathogenesis of ARWMC, and also the important causation of cognitive impairment in elderly people.

Key words: Endothelial cells, Stem cells, Leukoaraiosis, Flow cytometry, Magnetic resonance imaging, Neuropsychological tests

摘要： 目的   探讨年龄相关性脑白质改变的形成机制，以及与循环血内皮祖细胞数目变化和认知功能之间的关系，为年龄相关性脑白质改变及老年人群认知功能障碍的早期防治提供理论依据。方法   经CT 或MRI 明确诊断的年龄相关性脑白质改变患者40 例，采用流式细胞术检测循环血内皮祖细胞数目，简易智能状态检查量表（MMSE）和蒙特利尔认知评价量表（MoCA）评价认知功能。采用完全随机设计的单因素方差分析和R × C 表格资料的χ2检验进行单因素筛查，Logistic回归分析（向后剔除法）确定年龄相关性脑白质改变危险因素。结果   流式细胞术检测显示，年龄相关性脑白质改变组患者循环血内皮祖细胞数目减少，且以病情严重者（29.50 ± 6.26）减少更为显著，与正常对照组（70.50 ± 8.71）和轻至中度组（58.99 ± 7.78）比较，差异具有统计学意义（均P = 0.000）；循环血内皮祖细胞数目变化与年龄相关性脑白质改变严重程度呈负相关（r = -0.562，P = 0.001）。重度组患者MMSE 评分（23.85 ± 2.35）和MoCA 评分（19.80 ± 3.38）显著低于正常对照组（27.10 ± 1.80，26.60 ± 1.23）和轻至中度组（25.80 ± 2.02，23.30 ± 2.87），组间差异有统计学意义（均P < 0.05）。年龄相关性脑白质改变组患者主要表现为视空间及执行能力、延迟回忆及定向力障碍（均P < 0.05）。结论   循环血内皮祖细胞数目变化可作为年龄相关性脑白质改变发生的预测因素，并是反映疾病严重程度的有效指标。其数目减少可能是形成年龄相关性脑白质改变的重要机制，并是导致老年人群认知功能障碍的重要病因。

关键词: 内皮细胞, 干细胞, 脑白质疏松症, 流式细胞术, 磁共振成像, 神经心理学测验