MONDAY, Sept. 13 (HealthDay News) -- New research suggests that
biomarkers in the blood may help diagnose Alzheimer's disease
before it progresses, potentially opening the door to better
While there are currently no treatments that can halt or delay
the onset of the disease, the hope is that being able to diagnose
Alzheimer's earlier could provide clues about what medication might
prevent it from getting worse, the study authors said.
"Most of the research to this point has been done on those who already have Alzheimer's disease," said study author Sid O'Bryant, director of research for the F. Marie Hall Institute for Rural and Community Health at Texas Tech University Health Sciences Center. "We need to be able to identify those at greatest risk."
In the study, researchers analyzed 100 biomarkers in the blood
serum drawn from 197 patients with Alzheimer's and 203 people
Participants were assigned a "risk score" based on levels of the
various biomarkers, including C-reactive protein and
interleukin-10, which have been associated with inflammation. About
22 of the 100 biomarkers emerged as the most significant, according
to the study.
The biomarker risk score accurately identified 80 percent of
those who had Alzheimer's disease. When Alzheimer's risk factors,
such as age, sex, education and genetic information, were included,
the test's accuracy was 94 percent.
Conversely, the biomarker risk score accurately identified who
did not have the disease 91 percent of the time. When the other
Alzheimer's risk factors were included in the score, accuracy was
The study is published in the September issue of the
Archives of Neurology.
The study is promising but has limitations, said Dr. Ralph
Nixon, director of the NYU Center of Excellence on Brain Aging.
The people in the study already had Alzheimer's, so more
research is needed to determine if the test is sensitive and
specific enough to be used in people with symptoms such as mild
cognitive impairment, a risk factor for Alzheimer's.
Diagnosing Alzheimer's disease is typically done through a
clinical examination with a neurologist. Neuroimaging tests are
done to rule out other conditions causing the mental declines, such
as stroke or brain tumors, Nixon said.
Other methods include a spinal tap or specialized MRIs that can
detect amyloid protein, but these are not typically available
outside of large metropolitan hospitals or as part of medical
studies, O'Bryant noted.
"The real major bottleneck in the field is not so much to detect Alzheimer's, which we can do reasonably well once it has progressed, but to detect the earliest signs of the disease, or to be able to distinguish subtle memory impairment that is related to Alzheimer's from other causes of mild memory impairment," Nixon said.
Currently, several medications can help treat the symptoms of
memory loss, but none do anything about the underlying causes of
the disease, Nixon said.
"The purpose of the biomarkers is to find a way to identify those changes that happen at the very early stage, so that we can nip it in the bud before things get so advanced in the brain; that's [when] it's very difficult to find a medication to reverse it," Nixon said.
Researchers developed the blood test in conjunction with
Rules-Based Medicine in Austin, Texas. It has applied for a patent,
In a second study from the same journal, researchers from
University of Virginia Health System conducted an 18-month trial to
test the safety of pioglitazone (Actos), a diabetes drug, for use
in Alzheimer's patients.
Though the drug did not improve Alzheimer's symptoms, there were
few side effects, according to the study.
Researchers stressed the trial involved only 25 patients and was
designed only to test safety, not efficacy, researchers stressed.
The next step will be larger trials to test effectiveness.
"There is a lot of encouraging preclinical data that the pathways and the mechanisms this drug would be targeting are highly relevant to the development of Alzheimer's disease," said Nixon, who was not involved in the research. "There is a quite strong rationale for looking at drugs with this type of action."
The study was funded by the National Institutes of
Health/National Institute on Aging.
National Institute on Aging has more on
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