Test Shows Promise for Early Detection of Alzheimer’s

New Alzheimer research could lead to blood or urine screening test

(RxWiki News) Researchers continue to look for new ways to detect Alzheimer’s disease before symptoms like dementia take shape. Reliable diagnostics may increase the effectiveness of treatments.

New research into tiny protein fragments contained in cerebrospinal fluid offers the promise of eventually providing a better method of early Alzheimer’s detection.

This brain condition, marked by memory loss, dementia and other impacts, is primarily diagnosed after symptoms have started.

This new research could ultimately lead to blood or urine screening tests for Alzheimer’s disease.

"Talk to your doctor about early detection of Alzheimer’s disease."

Claudio Soto, PhD, of the University of Texas Medical School Houston’s Department of Neurology, co-authored this study.

His team adapted for Alzheimer’s diagnosis a technique called protein misfolding cyclic amplification or PCMA. They had previously used the PCMA method to detect misfolded proteins responsible for conditions like mad cow disease.

The researchers analyzed cerebrospinal fluid from 50 patients diagnosed with probable Alzheimer’s disease and found higher-than-normal levels of Aβ oligomers, a type of molecule which plays a key role in the development of Alzheimer's disease.

"This is the key molecule and could be the best, most reliable way to make an early diagnosis,” Dr. Soto said.

“That's been the biggest problem in the field: you can't identify patients until they are already sick," he said.

Testing Aβ oligomers as signs of Alzheimer's, the researchers also analyzed the cerebrospinal fluid of 39 cognitively normal patients with non-degenerative neurological diseases and 37 patients with neurodegenerative diseases other than Alzheimer’s.

When comparing the probable Alzheimer’s patients with those diagnosed with neurodegenerative diseases other than Alzheimer’s, Dr. Soto’s group found the PCMA test showed 100 percent sensitivity and 94.6 percent specificity.

Sensitivity is the ability of a test to correctly classify an individual as having a particular condition, in this case Alzheimer’s. Specificity is the ability of a test to classify an individual without the condition.

"These findings provide the proof-of-principle basis for developing a highly sensitive and specific biochemical test,” to diagnose Alzheimer’s, according to Dr. Soto and team.

Dr. Soto said the Aβ oligomer now thought to be an Alzheimer’s indicator “may be circulating in the body years if not decades before cognitive symptoms arise.”

Dr. Soto said the next step is to adapt the test for use with blood or urine samples instead of cerebrospinal fluid. The blood or urine test could be used to screen people for Alzheimer’s disease.

In their study, the authors wrote that when treating diseases affecting the brain like Alzheimer’s disease, “It is crucial to intervene before irreversible neuropathological changes occur. Early diagnosis … is of utmost importance.”

This research was published March 20 in Cell Reports, a peer-reviewed life sciences journal.

Funding was provided through grants from the Alzheimer’s Association, CART Foundation, Mitchell foundation and the Italian Ministry of Health.

Dr. Soto holds several patents related to his research into brain disorders and also founded a biotech company focusing on commercial neurological diagnostic methods.

Review Date: 
March 23, 2014