Background
Possession of APOEɛ4 is a strong risk factor for late-onset Alzheimer's disease and is associated with loss of synaptic proteins in the elderly even in the absence of Alzheimer's disease.
Conclusions
People with an APOEɛ32 genotype have a reduced risk of Alzheimer's disease. It may be relevant that they have a higher level of post-synaptic proteins in the hippocampus even in earlier adulthood.
Methods
We measured synaptophysin, PSD95, drebrin, SNAP-25, and septin 7 by ELISA in hippocampus and superior temporal gyrus from 103 adults aged <75 without dementia. Corresponding gene expression was measured by RT-PCR.
Objective
We hypothesized that ɛ4 allele possession in non-demented adults aged under-75 would also be associated with alterations in the levels of synaptic proteins.
Results
There was no evidence that ɛ4 affected levels of the proteins measured. Instead we found an increase in post-synaptic proteins in the hippocampi of those with an ɛ32 genotype. The evidence was strongest for drebrin (p = 0.011). There was some evidence of increased synaptic protein gene expression in ɛ4 carriers. Conclusions: People with an APOEɛ32 genotype have a reduced risk of Alzheimer's disease. It may be relevant that they have a higher level of post-synaptic proteins in the hippocampus even in earlier adulthood.