A cross-sectional study of lipids and ApoC levels in Alzheimer's patients with and without cardiovascular disease

Background. There is increasing evidence supporting the role of atherogenic phenomena in Alzheimer's disease (AD). The possible significance of specific plasma lipid levels in the pathogenesis of AD remains controversial. While lipids such as cholesterol or chaperons such as apolipoprotein (Apo) E2 to ApoE4 have been assessed in AD, ApoC2 and ApoC3 have not been studied before. The present study investigated possible differences in levels of these lipids in AD patients, with or without cardiovascular diseases or risk factors. Methods. This is a cross-sectional study. The medical charts of patients diagnosed with probable AD were screened for the presence of cardiovascular disease and cardiovascular risk factors. Included in the study were 105 AD patients: 53 with cardiovascular risk factors (AD(+CVD)) and 52 without risk factors (AD(-CVD)). Blood samples were analyzed for lipoproteins, ApoC2, and ApoC3. We used t tests, chi-square tests, and regression analyses to identify significant differences and to compare the relationships of variables among the groups. Results. ApoC2 levels (3.5 +/- 0.3 and 3.4 +/- 0.4 mg/dl, respectively), ApoC3 (13.7 +/- 0.9 and 14.7 +/- 1.1 mg/dl, respectively), and high-density lipoprotein (HDL)/non-HDL ApoC3 ratios (1.6 +/- 0.2 and 1.3 +/- 0.2, respectively) were similar for the AD patients with and without cardiovascular risk factors. Levels of total cholesterol, triglycerides, low-density lipoproteins (LDL), very LDLs, and HDLs were similar in the two groups. A substantial proportion of both AD+CVD and AD-CVD patients showed high levels of total cholesterol and LDL, as well as low levels of HDL, ApoC2, and ApoC3, compared to normative values. Surprisingly, patients treated by cognitive enhancers showed significantly higher cholesterol (p = .002) and triglyceride (p = .015) levels, independent of age, gender, and cognitive level. Conclusions. There was no difference between AD patients, either with or without cardiovascular diseases or risk factors, with respect to plasma lipid profile, including ApoC2 and ApoC3. This could indicate that lipid metabolism may play a role in AD, whether with or without cardiovascular risk factors. The higher levels of some lipids, observed in a subset of patients treated by cognitive enhancers, deserves further investigation.