Abstract

The effect of APOE e4 allele on brain perfusion SPECT in late onset Alzheimers disease by an automated program, 3DSRT

Author(s): Seiju Kobayashi, Takao Ishii, Masaru Tateno, Hitoshi Sohma, Yasuo Kokai, Yoichi M Ito, Tomo Iwamoto, Kengo Furuse, Hanako Tsujino, Hidetoshi Morii, Wataru Ukai, Eri Hashimoto, Kumiko Utsumi, Chiaki Kawanishi

Aim: The Apolipoprotein E (APOE) ε4 allele is a risk factor for developing Alzheimer’s disease (AD), however its impact on cerebral functional changes in AD remains controversial. Previous studies reported conflicting results or failed to confirm any association, possibly because they failed to consider either the effect of patient age at onset or that of clinical stage. We performed functional neuroimaging studies using current improved techniques to re-examine the effect of APOE ε4 allele, taking both the age at onset and clinical stage into account.

Methods: 111 late onset AD (LOAD) subjects were divided into 3 subgroups based on Clinical Dementia Rating (CDR). We investigated the influence of ε4 allele on functional cerebral changes in each group of LOAD by using cutting-edge analysis software, 3DSRT.

Results: The APOE ε4 allele was significantly associated with relatively preserved cerebral blood flow in the cerebral cortices. The influence of APOE ε4 allele is not apparent in the mild stage, but is significantly demonstrable in the moderate stage.

Conclusion: Dividing AD subjects into subgroups based on the severity as well as the age at onset is important for precise outcomes. This study may help resolve the uncertainties of previous studies which reported conflicting results or failed to confirm any association. We believe this is the first study focused on the effect of APOE ε4 allele on functional cerebral changes at each stage of AD.