Gene polymorphisms of CETP and apolipoprotein E in elderly subjects with cognitive impairment

The association of cholesteryl ester transfer protein (CETP) and apolipoprotein E (APOE) gene polymorphisms with mild cognitive impairment (MCI) is under debate. Our aim was to evaluate the relationship between APOE and CETP genotypes with healthy ageing. We analysed 267 elderly subjects (55 to 80+ years), 163 with MCI and 104 healthy, and 50 healthy control subjects (35 to 55 years) from a Romanian population. Biochemical parameters and thyroid hormones were assayed in plasma. APOE and CETP TaqIB gene polymorphisms were determined. Elderly subjects had higher frequency of ɛ3/ɛ2 genotype (14.6% vs. 4%, P<0.001) than controls. Elderly subjects with MCI had lower high density lipoproteins (HDL) cholesterol (P=0.031), apoA-I (P=0.018), T3 (P=0.002), T4 (P=0.028) and TSH (P=0.001) hormone levels, higher systolic blood pressure (P=0.005), lower frequency of CETP B2 allele than the age-matched subjects. Healthy elderly subjects had CETP B2 allele associated with higher plasma apoA-I (P=0.021), lower circulating collagen (P=0.001) levels, and an increased frequency of the combined APOE ɛ2- CETP B2 genotype (18.3%) relative to MCI elderly subjects (7.6%, P=0.011). Healthy elderly subjects are characterized by higher HDL cholesterol, apoA-I levels and higher frequency of the combined APOE ɛ2 and CETP B2 alleles, indicating this pattern as representative for healthy ageing.