“We are close to developing a blood test that will be able to detect Alzheimer’s before clinical diagnosis is possible,” says Dimitrios Kapogiannis, a neuroscientist at the National Institute on Aging and professor at Johns Hopkins University in the US state of Maryland, who unveiled the results of his research to the public last week. The new method promises to detect the disease as many as 10 years before the first symptoms appear.
Speaking after a presentation at the Society for Neuroscience conference in Washington, where he presented the new test procedure, Kapogiannis told Kathimerini about the progress of his research and his hope that a commercial version of the test will be ready in less than three years from now.
The Greek neuroscientist, who graduated from the University of Athens Medical School in 1998, has been living and working in the United States for the past 14 years. At the same time, Kapogiannis works as a researcher at the country’s National Institute of Health. Although the test has been tried out on just 174 individuals so far, its diagnosis has been 100 percent accurate.
Ever since the disease was first diagnosed by German psychiatrist and neuropathologist Alois Alzheimer in 1906, scientists have been trying to come up with ways to detect it before the onset. One problem is that when the first signs of Alzheimer’s begin to appear, it is already too late as up to 50 percent of the subject’s brain cells have been lost or severely damaged.
Alzheimer’s is partly defined by the accumulation of proteins called amyloid beta and tau in the brain. Meanwhile, a third protein, IRS-1, which is involved in insulin signaling, appears to be defective in Alzheimer’s patients.
“When a brain cell is affected by Alzheimer’s, it is deprived of the energy to remove the protein deposits on the surface of the cell,” Kapogiannis said. However, those accumulations start as many as 10 years before the first signs of the disease, which makes scientists optimistic that they can speed up the diagnostic process.
The researchers examined blood samples from healthy individuals as well as Alzheimer’s patients that had been collected 10 years before the first symptoms. From these samples, the scientists isolated exosomes, small lipid sacs which are released by different cell types and which travel between cells transferring information. Kapogiannis’s team managed to isolate these nano-sized vesicles and examined whether they carried the three protein types associated with Alzheimer’s.
“Looking at exosomes in the blood is like looking at brain cells which no one would be able to see unless they carried out a brain biopsy, which is too invasive a procedure,” he said. “Looking at these exosomes one can see what is inside the brain cell of an Alzheimer’s patient while he is still alive,” he said.
Despite early signs that the test can be very effective for an early Alzheimer’s diagnosis, this is very hard to prove, he said, adding that tests are carried out by a small group of researchers.
“We are planning to conduct the test on samples of hundreds or even thousands of people. Nevertheless, the results so far are clear enough to create a lot of hope.”