A Proteomic Approach To Alzheimer’s Disease Diagnosis

The diagnosis of Alzheimer’s disease is fraught with difficulties stemming from its similarity to other types of cognitive impairment and the large, estimated time lag between the onset of neurodegeneration and the manifestation of clinical symptoms. To address this problem, an international group of scientists working with a development-stage diagnostics company, Satoris, screened blood samples that had been drawn from 259 individuals with Alzheimer’s disease or in a control group 2 to 6 years ago. Half of the samples were examined for 120 proteins known to be involved in cellular communication. This identified 18 plasma proteins that were expressed at significantly different levels and had predictive value in distinguishing between the two groups.

Application of the biomarker analysis to the other half of the archived blood samples demonstrated that the test was able to correctly identify 20 of the 22 patients (91% accuracy) with cognitive impairments who developed Alzheimer’s disease 2 to 5 years after the blood was drawn and to discern all eight patients who later developed other dementias.

An evaluation of the proteins that comprise the biomarker assay segregated them into two independent regulatory pathways: One network involves tumor necrosis factor-alpha (TNF-a) and monocyte-colony stimulating factor (M-CSF), while the other pathway is centered on epidermal growth factor (EGF). This was consistent with a separate analysis that characterized the proteins as involved in immune response, hematopoiesis, and apoptosis.

The reported blood test underpins an effort at Satoris to commercialize proteomic-based diagnostic tests for Alzheimer’s disease and mild cognitive impairments. The results will require verification, and additional development work will be needed to finalize a commercial product.

Message posted by: Keith Markey