Blood Test May Detect Alzheimer's In Patients 16 Years Before Symptoms Appear
SAN FRANCISCO (CBS SF) - Scientists have found a way to diagnose Alzheimer's disease in patients long before symptoms appear by measuring a protein found in brain and spinal cord fluid, and blood serum.
The protein is called neurofilament light chain, or NfL.
The study, titled "Serum neurofilament dynamics predicts neurodegeneration and clinical progression in presymptomatic Alzheimer's disease" was published in the January issue of Nature Medicine.
Alzheimer's disease patients first show symptoms of short-term memory loss, and become increasingly confused, exhibiting more and more behavioral problems. There is no cure.
Older people are at greatest risk, but certain genes are associated with an even higher risk factor for the disease. Participants in the study were members of families in the so-called Dominantly Inherited Alzheimer Network (DIAN), who carry such gene mutations.
"Since the age of symptom onset tends to be consistent for a given mutation, it is possible to calculate for participants an estimated years to symptom onset from the known onset of individuals with the same mutation," according to the study.
Currently, blood tests for Alzheimers measure so-called amyloid proteins to determine the progression of the disease. Not so, with the with the patients in the study.
"Our blood test does not look at the amyloid, but at what it does in the brain, namely neurodegeneration. In other words, we look at the death of neurons," says lead researcher Mathias Jucker, professor of cell biology of neurological diseases at the German Center for Neurodegenerative Diseases, in Science News.
When brain cells die, proteins remain in the blood and they degrade quickly, but not all of them.
"An exception, however, is a small piece of so-called neurofilament that is surprisingly resistant to this degradation," says Jucker.
The researchers monitored levels of NfL in some 405 patients over the course of 7 years, and found "noticeable changes in the blood" as early as "16 years before the (predicted) onset of dementia symptoms."
According to the study, levels of NfL in the blood can "sensitively" predict the course of the disease in patients.
"The more neurofilament you have in the blood, the more brain damage you have," says Jucker.
The correlation is a considerable breakthrough for the more than 5 million people who suffer from Alzheimer's disease in the U.S., and 24 million worldwide. For those patients who are presymptomatic, the study has even more impact.
Treatment for the disease could start much earlier then the onset of symptoms by measuring the NfL in cerebro-spinal fluid and serum.
Also, using blood tests to monitor the progression of the disease instead of tests like PET/MRI brain scans may be more reliable and far less expensive.
"The fact that there is still no effective treatment for Alzheimer's is partly because current therapies start much too late," said Jucker.
The research is ongoing, but the NhL test is available for commercial use.
CBSSF.com writer, producer Jan Mabry is also executive producer Bay Sunday, Black Renaissance and host of The Bronze Report. She lives in Northern California. Follow her on Twitter @janmabr.
