[ad_1]
Scientists said Monday they had developed a way to predict whether patients will develop Alzheimer’s disease by testing their blood, in what experts hailed as a possible “game changer” in the fight against the debilitating disease.
About 50 million people live with Alzheimer’s, a degenerative brain disease that accounts for more than half of dementia cases worldwide. Although its precise mechanism is not fully understood, Alzheimer’s appears to be the result of protein build-up in the brain that is believed to lead to the death of neurons. Some of these proteins can be traced in the blood of patients and tests based on their concentrations can be used to diagnose the disease.
Scientists from Sweden and Britain now believe that blood tests can be used to predict Alzheimer’s years before symptoms appear.
Writing in the journal Nature Aging, they described how they developed and validated individual risk models based on the levels of two key proteins in blood samples taken from more than 550 patients with minor cognitive impairments.
The model based on these two proteins had an 88% success rate in predicting the onset of Alzheimer’s disease in the same patients over the course of four years.
They said that while more research is needed, their prediction method could have a significant impact on Alzheimer’s cases, given that “plasma biomarkers” from blood tests are “promising due to their high accessibility and low cost.”
Richard Oakley, head of research at the Alzheimer’s Society, said the main fight to combat the disease was to diagnose cases early enough to intervene with experimental treatments.
“If these blood biomarkers can predict Alzheimer’s disease in larger and more diverse groups, we could see a revolution in the way we test new drugs for dementia,” he said.
Musaid Husain, a professor of neurology at the University of Oxford, described Monday’s research as a “potential game changer.”
“For the first time, we have a blood test that can predict well the risk of later development of Alzheimer’s disease in people who have mild cognitive symptoms,” said Husain, who was not involved in the study.
“We need further validation (of the results), but in the context of other recent findings, this could be a transformative step towards an earlier diagnosis, as well as testing new treatments in the earlier stages of the disease.”
Test goes on sale
Meanwhile, blood tests have also been released, although the reactions have been mixed.
Independent experts are suspicious because key test results have not been published and the test has not been approved by the US Food and Drug Administration (FDA); It is sold under more general rules for commercial laboratories. But they agree that a simple test that can be performed in a doctor’s office has long been needed.
To be diagnosed with Alzheimer’s, people must have symptoms like memory loss plus evidence of a build-up of a protein called beta-amyloid in the brain.
The best way now to measure protein is an expensive PET brain scan that is generally not covered by insurance either. That means most people don’t have one and wonder if their problems are due to normal aging, Alzheimer’s, or something else.
The C2N Diagnostics of St. Louis blood test aims to fill that gap. The founders of the company include Drs. David Holtzman and Randall Bateman of the Washington University School of Medicine, who led the research that led to the trial and are included in a patent that St. Louis University licensed to C2N.
About the test
The test is not designed for general screening or for people without symptoms; is for people 60 years of age and older who have trouble thinking and are being evaluated for Alzheimer’s disease. It is not covered by insurance; the company charges $ 1,250 and offers discounts based on income. Only doctors can request the test and the results are obtained within 10 days. It is sold in every state in the US except a few, and has just been licensed for sale in Europe.
It measures two types of amyloid particles plus various forms of a protein that reveal whether someone has a gene that increases the risk of getting the disease. These factors are combined into a formula that includes age, and patients receive a score that suggests a low, medium, or high probability of having amyloid accumulation in the brain.
If the test puts them in the low category, “it’s a compelling reason to look for other things” besides Alzheimer’s, Bateman said.
“There are thousands of things that can cause someone to suffer cognitive decline,” from vitamin deficiencies to medications, Holtzman said.
“I don’t think this is any different than the tests we do now,” except that it involves a blood test rather than a brain scan, he said. “And those aren’t 100% accurate either.”
