Evaluation of Apolipoprotein E Fragmentation as a Biomarker for Alzheimer's Disease.

Recent studies have supported a role for the proteolytic cleavage of apolipoprotein as a potential mechanism for the enhanced dementia risk associated with Alzheimer's disease. To determine whether fragmentation is correlated with AD, ELISA assays were performed with cerebral spinal fluid (CSF) and plasma samples utilizing an antibody that specifically detects a 17 kDa amino-terminal fragment (p17) of (nApoECF antibody). In CSF samples, levels of fragmentation were minimal in both neuropathological normals (NPNs) and AD cases and there were no significant differences between the two cohorts across genotypes. Similar results were found in plasma samples where the p17 fragment comprised only 8.4% of the total level of identified APOE. As with CSF, there were no significant differences found between NPNs and AD cases in terms of the amount of nApoECF quantified. Taken together, these results suggest that the p17 amino-terminal fragment of is not correlated with AD or genotype in the plasma or CSF.