Their multiyear study, published March 9, 2014, in Nature Medicine, offers hope for a test that can read the signature of Alzheimer’s in the blood before the onset of symptoms. A laboratory test could scan blood samples searching for declining levels of 10 chemicals that indicate damage to nerve-cell membranes, which are made of phospholipids. The researchers showed that this 10-phospholipids panel can predict who will develop Alzheimer’s nine times in 10—a prediction rate better than many standard diagnostic exams in use today. For example, mammography accurately predicts breast cancer roughly eight in 10 times, according to the National Cancer Institute.
“We wanted to be able to identify individuals at risk of Alzheimer’s disease with the long-term goal of being able to develop a therapeutic strategy to prevent, restrict or delay the onset of cognitive deficits associated with this devastating disease,” said Susan Fisher, chair of the Department of Clinical Sciences in Temple’s School of Medicine.
The research team arrived at the 10-metabolite panel by comparing the blood of people who developed Alzheimer’s, or a mild cognitive impairment that often leads to Alzheimer’s, to those who did not. The researchers recruited 525 people ages 70 and older, collected blood samples and administered annual cognitive testing. In year three, 74 participants showed signs of cognitive impairment, including 28 who developed the memory problems during the course of the study. The remaining 46 began the study with some form of impairment. By comparing blood samples from those who developed impairment to samples from those who did not, researchers found 10 phospholipids that differed between the two groups.
Fisher played a critical role in designing the study. She examined it for places where bias might interfere with the research and found ways to prevent it. She also guided decisions about selecting trial participants and how to keep them involved throughout the years of the study.
“We recruited patients from family-physician practices,” Fisher explained. “Had we recruited only from neurology practices, the study population would likely have had more cases of Alzheimer’s disease. Such a skewed population would have muddled the research results.”
Among the many challenges for Alzheimer’s researchers is finding a way to detect the disease before its damage has gone too far. Typically, by the time the first overt symptoms appear, patients’ brains are riddled with damage.
If physicians could detect the disease earlier, existing or new medications could slow, and even eventually halt, further dramatic harm. Fisher noted that more studies on a larger, more diverse group of subjects is necessary before the test is proven for use in patients.
“The results are striking,” Fisher said, “but we’d like to know if they’re sustainable and can be replicated in a larger sample.”
For more information about this study, contact Rebecca Harmon at 215-707-8229 or [email protected].