Abstract
Previous findings demonstrated an altered pattern of amyloid-β protein precursor (AβPP) expression in platelets of Alzheimer's disease (AD) patients compared with either healthy control subjects or patients with non-Alzheimer-type dementia. In an attempt to explore the diagnostic potential of platelet AβPP metabolism, we have generated monoclonal antibodies directed to the N-terminal part of AβPP. We have observed two different antibody recognition patterns of AβPP: one resembling previously described 130 kDa and 105 kDa species and a novel AβPP 115 kDa form. This form was significantly increased in platelets of the mild cognitive impairment and AD group as compared to control subjects. The abundance of AβPP 115 kDa species correlated with the previously described AβPP 130/105 kDa ratio as well as with Mini-Mental State Examination score. Despite the inability of these particular monoclonal antibodies to recognize native forms of AβPP, identification of a new AβPP isoform in platelets as a potential AD biomarker can provide an additional tool for the development of a reliable diagnostic test to detect preclinical stages of AD.