In a breakthrough study, researchers at the University of Pennsylvania School of Medicine have pioneered a biomarker test that can confirm or rule out Alzheimer''s disease.
The test measures cerebrospinal fluid (CSF) concentrations of two of the disease''s biochemical hallmarks – amyloid beta42 peptide and tau protein.
With this information in hand, the scientists also predict whether a person''s mild cognitive impairment would convert to Alzheimer''s disease over time.
The research team, led by Dr. Leslie M. Shaw, Co-Director of the Penn Alzheimer''s Disease Neuroimaging Initiative (ADNI) Biomarker Core, could detect this devastating disease at the earliest stages, before dementia symptoms appeared and widespread irreversible damage occurred.
By improving upon a previously suggested pathological CSF biomarker signature, the researchers found evidence of neuron degeneration – marked by an increase in CSF concentration of tau proteins – and plaque deposition, indicated by a decrease in amyloid beta42 concentration.
Also, people with two copies of the genetic risk factor for Alzheimer''s disease, APOE å4 , had the lowest concentrations of amyloid beta42, compared to those with one or no copies.
"With this test, we can reliably detect and track the progression of Alzheimer''s disease," said Shaw.
He added: "Validated biomarker tests will improve the focus of Alzheimer''s clinical trials, enrolling patients at earlier stages of the disease to find treatments that can at least delay –and perhaps stop– neurodegeneration. In addition, prevention trials can test methods to delay or block mild cognitive impairment from converting to full-blown Alzheimer''s."
Currently, researchers are conducting further validation studies of the research test system.
Additional work is needed to develop additional biomarkers, as well as identify more genetic risk factors that will help distinguish Alzheimer''s from other neurodegenerative diseases characterized by cognitive impairments.
The study appears in the online edition of the Annals of Neurology.