Apolipoprotein E genotype and Lewy body disease

Area of Science:

• Neuroscience
• Genetics
• Pathology

Background:

• Lewy body disease (LBD) is a neurodegenerative disorder characterized by alpha-synuclein aggregation.
• The role of apolipoprotein E (APOE) genotype in LBD neuropathology remains incompletely understood.
• Excluding concurrent Alzheimer's disease is crucial for isolating LBD-specific pathological changes.

Purpose of the Study:

• To investigate the association between APOE genotype and specific neuropathological features in Lewy body disease (LBD).
• To determine if APOE alleles modify the density of beta-amyloid plaques and Lewy bodies.
• To assess the impact of APOE genotype on neuritic degeneration and other pathological markers in LBD.

Main Methods:

• Analysis of 18 LBD cases without concurrent Alzheimer's disease (CERAD criteria).
• Genotyping for APOE alleles (epsilon 2, epsilon 3, epsilon 4).
• Quantification of diffuse beta-amyloid plaque (A beta P) and Lewy body densities.
• Grading of CA2-3 neuritic degeneration, vacuolar change, nigral pathology, amyloid angiopathy, and subpial amyloid deposition.

Main Results:

• APOE allele frequencies: epsilon 2 (0.14), epsilon 3 (0.64), epsilon 4 (0.22).
• Mean A beta P density was significantly lower in APOE epsilon 3/3 cases compared to those with APOE epsilon 2 or epsilon 4 alleles (p < 0.02).
• CA2-3 neuritic degeneration was significantly greater in individuals with the APOE epsilon 4 allele compared to APOE epsilon 3/3 genotype (p < 0.05).

Conclusions:

• APOE genotype appears to influence neuropathological features in Lewy body disease.
• The APOE epsilon 4 allele is associated with increased CA2-3 neuritic degeneration.
• APOE epsilon 2 and epsilon 4 alleles may be linked to higher beta-amyloid plaque burden in LBD.