Apolipoprotein E levels in the cerebrospinal fluid of north Indian patients with Alzheimer's disease

Abstract

The etiology of Alzheimer's disease (AD) is multifactorial involving both genetic and environmental factors. Apolipoprotein E (ApoE) gene plays a pivotal role in risk and age of onset of AD. Although it is broadly accepted that ApoE genotype is linked to the pathogenesis of AD, there are still controversial results regarding the association of ApoE levels in cerebrospinal fluid (CSF) with the occurrence of AD. Some studies have shown a positive correlation between CSF ApoE levels and AD, whereas others showed no link. In this study, we measured ApoE levels to assess the usefulness of CSF ApoE as a diagnostic marker of AD by comparing the levels in 3 patient groups and in control participants. No significant difference was observed in CSF ApoE concentrations between the patients with AD and the controls. So, it appears that CSF ApoE measurement does not offer any diagnostic advantage for AD.

Figure 1.

In NAD, NC, HC as well as in the AD subpopulation, the CSF ApoE concentration was not significantly modified by the phenotype, even if a minor increase in ApoE level for individuals having 2 copies of the ∊4 allele was observed. The mean values are no copy of ∊4 allele, 22.7 ± 3.41 µg/mL; 1 copy of ∊ allele, 21.30 ± 2.08 µg/mL; 2 copies of ∊4 allele, 21.96 ± 1.20µg/mL. NAD indicates patients with dementias other than AD; NC, patients with neurological illnesses other than dementia; HC, age-matched healthy controls; AD, Alzheimer’s disease; CSF, cerebrospinal fluid; ApoE, apolipoprotein E.

Figure 2.

The CSF ApoE values are plotted according to the pathology. The statistical analysis with the Mann-Whitney U and Kruskal-Wallis tests did not show any significant differences between the different subpopulations. The mean values are AD group, 22.36 ± 2.35 µg/mL; NAD, 22.10 ± 3.49 µg/mL; NC, 22.55 ± 2.93 µg/mL; HC, 23.22 ± 2.21µg/mL. CSF indicates cerebrospinal fluid; ApoE, apolipoprotein E; AD, Alzheimer’s disease; NAD, patients with dementias other than AD; NC, patients with neurological illnesses other than dementia; HC, age-matched healthy controls.