Background: Details of the internal hippocampal structure visible at 4 T allow for in vivo volumetry of subfields. The aims of this study were: 1. To determine if Apo e4 has subfield specific effects in controls. 2. To study the influence of Apo e4 on hippocampal subfields in AD.
Methods: 81 subjects (66 controls, mean age 60.8+/-13.6, range: 28-85 years), and 15 AD (mean age 67.5+/-9.3) were studied. Entorhinal cortex, subiculum, CA1, CA1-CA2 transition zone, CA3-4 and dentate gyrus (CA3&DG) and total hippocampal volume were determined using a manual marking strategy.
Results: Significant effects for Apo e4 on the CA3&DG were found in the total control population (p=0.042) and in older controls (61-85 years) (p=0.036) but not in younger (28-60 years) controls. Significant effects for Apo e4 (p=0.0035) on CA3&DG were also found in a subgroup of older subjects and AD subjects. AD with Apo e4 had smaller CA3&DG than AD without Apo e4 (p=0.027).
Conclusions: These findings suggest that Apo e4 exerts a regionally selective effect on CA3&DG in normal aging and AD.