Park Mina, Lee Hong Pyo, Kim Junghyeob, Kim Dong Hyun, Moon Yeonsil, Moon Won-Jin
Department of Radiology, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea.
Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
J Neuroimaging. 2022 May;32(3):521-529. doi: 10.1111/jon.12960. Epub 2021 Dec 29.
Apolipoprotein E4 (APOE4) is a major genetic risk factor for Alzheimer's disease. However, the effect of APOE4 status on myelin remains unclear. This study investigated the effect of APOE4 on myelin content in cognitively impaired individuals using T2* gradient echo (GRE)-based myelin water fraction (MWF) imaging.
Between August 2017 and January 2019, we evaluated 39 cognitively impaired patients (median age, 75 years; male:female = 8:31; Alzheimer's disease: mild cognitive impairment = 11:28). We obtained brain MWF values from white matter hyperintensities (WMHs) and normal-appearing white matter (NAWM). Linear regression analysis was performed to investigate the relationship between the APOE4 status and MWF and cognitive function and MWF.
Among the 39 cognitively impaired patients, nine (23.1%) were APOE4 carriers and 30 (76.9%) were noncarriers. APOE4 carriers had a lower hippocampal volume than noncarriers (p = .045), but other brain volume parameters were not differed. After age adjustment, the APOE4 status was significantly associated with reduced MWF in NAWM (β = -0.310 per allele; p = .049) but not in WMH (β = -0.258 per allele; p = .113). After age adjustment, MWF in NAWM was significantly associated with Mini-Mental State Examination score (β = 0.313, p = .031).
T2* GRE-based MWF imaging can reveal myelin loss, particularly in NAWM, in cognitively impaired patients among APOE4 carriers. In vivo MWF in NAWM might be a novel imaging marker of Alzheimer's disease, for clarifying the interactions between the white matter and cognitive dysfunction with respect to the APOE4 status.
载脂蛋白E4（APOE4）是阿尔茨海默病的主要遗传风险因素。然而，APOE4状态对髓磷脂的影响尚不清楚。本研究使用基于T2*梯度回波（GRE）的髓磷脂水分数（MWF）成像，调查了APOE4对认知受损个体髓磷脂含量的影响。
在2017年8月至2019年1月期间，我们评估了39例认知受损患者（中位年龄75岁；男性:女性 = 8:31；阿尔茨海默病:轻度认知障碍 = 11:28）。我们从脑白质高信号（WMH）和正常脑白质（NAWM）中获取脑MWF值。进行线性回归分析以研究APOE4状态与MWF以及认知功能与MWF之间的关系。
在39例认知受损患者中，9例（23.1%）为APOE4携带者，30例（76.9%）为非携带者。APOE4携带者的海马体积低于非携带者（p = 0.045），但其他脑容量参数无差异。年龄校正后，APOE4状态与NAWM中MWF降低显著相关（每个等位基因β = -0.310；p = 0.049），但与WMH中MWF无关（每个等位基因β = -0.258；p = 0.113）。年龄校正后，NAWM中的MWF与简易精神状态检查表评分显著相关（β = 0.313，p = 0.031）。
基于T2* GRE的MWF成像可揭示APOE4携带者中认知受损患者的髓磷脂丢失，尤其是在NAWM中。NAWM中的活体MWF可能是阿尔茨海默病的一种新型成像标志物，用于阐明白质与认知功能障碍之间关于APOE4状态的相互作用。
