Department of Psychiatry, University of Bonn, Bonn, Germany.
Psychol Med. 2011 Sep;41(9):1997-2006. doi: 10.1017/S0033291711000067. Epub 2011 Feb 2.
The apolipoprotein E4 allele (ApoE4) is an established genetic risk factor for Alzheimer's disease (AD). However, its effects on cognitive performance and brain structure in healthy individuals are complex. We investigated the effect of ApoE4 on cognitive performance and medial temporal lobe volumetric measures in cognitively unimpaired young elderly with and without subjective memory impairment (SMI), which is an at-risk condition for dementia.MethodAltogether, 40 individuals with SMI and 62 without were tested on episodic memory and on tasks of speed and executive function. All participants were ApoE genotyped. 21 subjects with SMI and 47 without received additional structural magnetic resonance imaging. Volumetric measures of the hippocampus, the entorhinal cortex and the amygdala were obtained manually.
In the SMI group, ApoE4 carriers performed worse on the episodic memory (p=0.049) and showed smaller left hippocampal volumes (p=0.030). In the individuals without SMI, the ApoE4 carriers performed better on episodic memory (p=0.018) and had larger right hippocampal volumes (p=0.039). The interaction of group (SMI/no SMI) and ApoE genotype was significant for episodic memory (p=0.005) and right and left hippocampal volumes (p=0.042; p=0.035). There were no within-group differences or interaction effects on speed and executive function composite measures or other volumetric measures.
The negative effect of ApoE4 on episodic memory and hippocampal volume in SMI supports SMI as a prodromal condition of AD. The positive effects of ApoE4 in subjects without SMI adds to a number of reports on positive ApoE4 effects in young and very old individuals.
载脂蛋白 E4 等位基因（ApoE4）是阿尔茨海默病（AD）的既定遗传风险因素。然而，它对认知表现和健康个体的大脑结构的影响是复杂的。我们研究了 ApoE4 对认知表现和内侧颞叶体积测量的影响，这些测量是认知未受损的年轻老年人（即痴呆的高危人群）中存在和不存在主观记忆障碍（SMI）的情况。
共有 40 名 SMI 患者和 62 名无 SMI 患者接受了情景记忆和速度及执行功能任务的测试。所有参与者均进行了 ApoE 基因分型。21 名 SMI 患者和 47 名无 SMI 患者接受了额外的结构磁共振成像。手动获得海马体、内嗅皮质和杏仁核的体积测量值。
在 SMI 组中，ApoE4 携带者在情景记忆测试中表现更差（p=0.049），且左侧海马体体积较小（p=0.030）。在无 SMI 的个体中，ApoE4 携带者在情景记忆测试中表现更好（p=0.018），且右侧海马体体积较大（p=0.039）。组（SMI/无 SMI）和 ApoE 基因型的交互作用对情景记忆（p=0.005）和右侧和左侧海马体体积（p=0.042；p=0.035）具有显著影响。在速度和执行功能综合测量或其他体积测量中，没有组内差异或交互作用。
ApoE4 对 SMI 患者的情景记忆和海马体体积的负面影响支持 SMI 是 AD 的前驱期。ApoE4 在无 SMI 患者中的积极影响增加了许多关于年轻和非常老年个体中 ApoE4 积极影响的报告。
