An early diagnosis is necessary to intervene and slow down
the progression of neurodegenerative disease, such as Alzheimer’s disease (AD).
Unfortunately, the disease typically isn’t spotted until symptoms have already
appeared and amyloid plaques have begun to accumulate and cause damage to the
brain. A new blood test claims to be able to accurately identify Alzheimer’s
disease 10 years before the onset of symptoms.
The paper was published in The Journal of the Federation of American Societies for Experimental Biology. Lead author Dimitrios Kapogiannis
from the National Institute on Aging in Baltimore presented the research this
week at the 2014 meeting of the Society for Neuroscience in Washington, DC.
The blood test was performed on 174 patients with various
degrees of neurological health: 84 of the participants were healthy adults, 20
were elderly adults with no dementia, and 70 had been diagnosed with AD. The
researchers also had access to frozen blood samples from 20 of the AD patients
that had been taken anywhere from 1-10 years prior to the diagnosis.
AD patients are believed to have decreased levels of the
active form of protein insulin receptor substrate 1 (IRS-1), which is used to
facilitate insulin signals to the brain. The blood test targets that protein,
searching for signs of insulin resistance. Not only did they find that the
individuals with AD have higher levels of inactive IRS-1 (as was expected based
on prior research), but they were even able to detect that defective imbalance
in the blood samples taken 10 years before the AD diagnosis. The test was 100%
accurate in separating the controls from those with AD, and also identified
over 97% of the patients with type 2 diabetes.
“This study shows that insulin resistance is a major central
nervous system metabolic abnormality in AD that contributes to neural cell
damage,” senior author Edward Goetzl of the National Institute on Aging said in
a press release. “As insulin resistance is a known condition in type 2 diabetes
mellitus and is treatable with several classes of existing drugs, these
treatments may be useful as part of a multi-agent program for AD.”
There have been other AD tests announced this year that use
different biomarkers to predict disease. Based on 10 proteins found in the
blood, a team from Oxford predicted onset of AD within a year for over 1,100
participants, with 87% accuracy. A team from Georgetown University screened for
10 lipids in 525 participants, and was 90% accurate in predicting disease in
three years.
This current test is still in its early stages, and larger
studies will be needed to replicate and validate these findings. The
researchers are confident that using IRS-1 as a biomarker will be able to stand
up to that scrutiny and will allow for early intervention of AD in the future.
“We believe our assays will prove instrumental in
identifying early-stage AD patients for entry in clinical trials and thereby
help to enrich the study population. We invite pharmaceutical companies and
university researchers to contact us about collaborating or partnering to
generate additional data,” commented John Osth. Osth is President and CEO of NanoSomiX, a California-based biotech company that helped fund the research and
hopes to make the test commercially viable in the future.
Source:iflscience.com
