Is neuropathological heterogeneity in Alzheimer's disease related to apolipoprotein genotype?

The abundance of senile plaques (SP) and neurofibrillary tangles (NFT) was studied in cortical and subcortical regions from 30 patients with Alzheimer 's disease (AD) expressing different apolipoprotein E (apoE) genotypes. Pri ncipal components analysis (PCA) was used to identify the most important ne uropathological variations between individual patients and to determine whe ther these variations were related to apoE genotype. The first two principa l components (PC) accounted for 60% and 40% of the total variance of the SP and NFT data respectively. The abundance of SP in the frontal and occipita l cortex and NFT in the frontal cortex, amygdala and substantia nigra were positively correlated with the first principal component (PC1). Analysis of the SP data revealed that the apoE score of the patient (the sum of the tw o alleles) was positively correlated with PC1 while analysis of the NFT dat a revealed no significant correlations between apoE score and the PC. The d ata suggest that apoE genotype was more closely related to variations in th e distribution and abundance of SP than of NFT. In addition, a more rapid s pread of SP into the frontal and occipital cortex may occur in patients wit h a high apoE score.