Differentially charged isoforms of apolipoprotein E from human blood are potential biomarkers of Alzheimer's disease.

INTRODUCTION: Alzheimer's disease (AD) is the major cause of dementia among the elderly. Finding blood-based biomarkers for disease diagnosis and prognosis is urgently needed. METHODS: We studied protein distributions in brain tissues, cerebrospinal fluid (CSF), and blood of AD patients by using proteomics and a new proteomic method that we call "2D multiplexed Western blot" (2D mxWd). This method allows us to determine in multiple samples the electrophoretic patterns of protein isoforms with different isoelectric points. RESULTS: Apolipoprotein E (ApoE) displays a unique distribution of electrophoretic isoforms in the presence of AD and also a unique pattern specific to the APOE genotype. CONCLUSIONS: The isoelectric distribution of differentially charged ApoE isoforms was used to determine the presence of AD in a small group of samples. Further studies are needed to validate their use as predictors of disease onset and progression, and as biomarkers for determining the efficacy of therapeutic treatments.