Blood tests are starting to show real potential as a way of detecting Alzheimer’s disease in its early stages, with a number of studies producing highly promising results in the past couple of years. Joining them is a new test that can analyze markers in the blood of those with mild memory loss to determine the risk of them going on to develop Alzheimer’s within two to four years.
Because Alzheimer’s disease is difficult to diagnose through current methods, it is often not picked up until the cognitive decline associated with the condition is well progressed. So the search is on for alternatives to the expensive and invasive PET scans and fluid sampling currently used to measure markers of the diseases, and blood tests are emerging as an exciting possibility.
These tests are designed to scan the blood for early signs of the disease, such as toxic proteins called tau and amyloid, while others search for proteins that have misfolded or are released into the blood as a result of brain cell damage. While there is further work to be done, these tests have demonstrated the potential to identify the disease anywhere from years to more than a decade before clinical symptoms appear, leaving the door open for more effective treatments and management of the condition.
Led by scientists at Sweden’s Lund University, the team behind the latest breakthrough is also working to pick up the disease during its early stages and before it develops into dementia. The research focuses on two proteins in the blood called phosphorylated tau and neurofilamet light, which have both featured as part of the aforementioned blood testing technologies.
The study involved 573 subjects with mild memory loss and an average age of 71. Using the blood test to analyze levels of these two proteins in the blood, the team developed a model that combined these two bits of data and used them to predict which subjects would go on to develop dementia caused by Alzheimer’s, which accounts for 50 to 70 percent of all dementia cases.
“Many people with Alzheimer’s disease currently seek care when they have only developed mild memory impairment, meaning many years before the dementia stage of the disease,” explains Oskar Hansson, who led the research. “It is often difficult for doctors to give the correct diagnosis in people with mild memory impairment, as many different conditions other than Alzheimer’s can be the cause. In this study we developed a model that is based on the results of a simple blood test and that with a high degree of validity can predict who will develop Alzheimer’s dementia within four years.”
Taking things one step further, the team built an online tool that incorporates data like age, gender and results from cognitive tests and combines them with results from the blood test. This more complete picture of an individual’s circumstances can be used to predict their risk of developing Alzheimer’s within two years or four years, though the tool is only intended for use in research in its current form.
“Our goal over the last few years has been to find simple methods that can be used in primary care to make an early diagnosis and to begin treatment to relieve symptoms at an earlier stage,” says Hansson. “This will require more studies, but we have absolutely come one major step closer to our goal.”
The research was published in the journal Nature Aging.
Source: Lund University
