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Researchers may be closer to developing a new blood test that screens the blood for markers of Alzheimer's disease, according to a new study.
Unlike previous attempts at making blood tests for the disease, which mainly used tiny protein molecules called peptides, this test uses peptoids, which are synthetic molecules that can bind to human antibodies (proteins that the body produces to ward off disease).
"I think that looking at natural peptides is probably not a great place to look for things that will bind these disease-specific antibodies ," said study researcher Thomas Kodadek, a professor of chemistry and cancer biology at The Scripps Research Institute in Florida. "[Peptoids] don't occur in the body. They have different shapes, properties, chemistry than peptides do."
How the test works
The researchers took blood samples from 18 study participants, ages 62 to 91, including six patients diagnosed with Alzheimerâs disease , six healthy people and six patients diagnosed with Parkinson's disease.
They screened the blood, looking for peptoids that would bind to antibodies in people with Alzheimer's disease, but would not bind to antibodies in people who didn't have the condition.
They found three peptoids that distinguished the Alzheimer's patients from the healthy participants. These peptoids were three times more likely to bind to antibodies from the Alzheimer’s patients than antibodies from the healthy people or Parkinson's patients .
The researchers confirmed their finding by testing the blood of 38 participants, including 16 with Alzheimer's disease, 16 healthy people and six patients with lupus. They found that by screening the blood samples with the three peptoids, they could distinguish between the Alzheimer's patients , 14 of the healthy subjects and the six lupus patients.
The test could be beneficial to pharmaceutical companies recruiting Alzheimer's patients for clinical trials, Kodadek said, and that may lead to better treatments for the condition.
"I think that the problem that they are having right now — and there have been a lot of high-profile failures in Alzheimer’s trials — is they are getting people that are too far gone," Kodadek told MyHealthNewsDaily. Once there is a therapy in place, then this blood test could be used as a screening tool for catching the disease in its early stages, he said.
The future treatment of Alzheimer’s disease
Though there are advantages to such a screening tool for Alzheimer's disease, some physicians urged caution in reviewing the study's findings.
Small studies like this one tend to report better results for predicting and diagnosing the disease than those done in the general population, where there are more shades of grey across a wider spectrum of cognitive abilities, said Joe Verghese, a professor of neurology at Albert Einstein College of Medicine.
"The diagnostic ability would have to be established in the general population," Verghese said.
Further studies will measure biomarkers in patients with mild cognitive impairment (MCI) — a condition that can be precursor to Alzheimer's disease — and different types of cancers, the researchers said.
This test could become a commonly used in patients over age 50, Kodadek said. "I really see no reason why, in the future, this couldn't be a completely broad-based blood test that you can get in the doctor's office whenever you go for your annual physical," he said.
Approximately 5.1 million Americans may have Alzheimer's disease, according to the National Institute on Aging.
The study was published Jan. 7 in the journal Cell.