1Department of Psychology, Georgia State University, Atlanta, GA USA.
2Departments of Neurology, Emory University, 615 Michael Street, Suite 505, Atlanta, GA 30322 USA.
Transl Neurodegener. 2020 Feb 19;9:8. doi: 10.1186/s40035-020-0186-4. eCollection 2020.
Older African Americans are more likely to develop Alzheimer's disease (AD) than older Caucasians, and this difference cannot be readily explained by cerebrovascular and socioeconomic factors alone. We previously showed that mild cognitive impairment and AD dementia were associated with attenuated increases in the cerebrospinal fluid (CSF) levels of total and phosphorylated tau in African Americans compared to Caucasians, even though there was no difference in beta-amyloid 1-42 level between the two races.
We extended our work by analyzing early functional magnetic resonance imaging (fMRI) biomarkers of the default mode network in older African Americans and Caucasians. We calculated connectivity between nodes of the regions belonging to the various default mode network subsystems and correlated these imaging biomarkers with non-imaging biomarkers implicated in AD (CSF amyloid, total tau, and cognitive performance).
We found that race modifies the relationship between functional connectivity of default mode network subsystems and cognitive performance, tau, and amyloid levels.
These findings provide further support that race modifies the AD phenotypes downstream from cerebral amyloid deposition, and identifies key inter-subsystem connections for deep imaging and neuropathologic characterization.
与老年白人相比，老年非裔美国人更易患阿尔茨海默病（AD），而这种差异不能仅用脑血管和社会经济因素来解释。我们之前的研究表明，与白人相比，非裔美国人的轻度认知障碍和 AD 痴呆与脑脊液（CSF）中总tau 和磷酸化 tau 水平的增加幅度降低有关，尽管两种族之间β-淀粉样蛋白 1-42 水平没有差异。
我们通过分析老年非裔美国人和白种人的默认模式网络的早期功能磁共振成像（fMRI）生物标志物来扩展我们的工作。我们计算了属于不同默认模式网络子系统的区域节点之间的连接，并将这些成像生物标志物与 AD 相关的非成像生物标志物（CSF 淀粉样蛋白、总 tau 和认知表现）进行了关联。
我们发现，种族改变了默认模式网络子系统的功能连接与认知表现、tau 和淀粉样蛋白水平之间的关系。
这些发现进一步支持种族改变了大脑淀粉样蛋白沉积下游的 AD 表型，并确定了用于深入成像和神经病理学特征描述的关键子系统间连接。
