In a study to be published in the August 28 issue of the journal Neurology, scientists have taken a step toward developing a blood test for Alzheimer's, finding a group of markers that hold up in statistical analyses in three independent groups of patients.
"Reliability and failure to replicate initial results have been the biggest challenge in this field," says lead author William Hu, MD, PhD, assistant professor of neurology at Emory University School of Medicine. "We demonstrate here that it is possible to show consistent findings."
Hu and his collaborators at the University of Pennsylvania and Washington University, St. Louis, measured the levels of 190 proteins in the blood of 600 study participants at those institutions. Study participants included healthy volunteers and those who had been diagnosed with Alzheimer's disease or mild cognitive impairment (MCI). MCI, often considered a harbinger for Alzheimer's disease, causes a slight but measurable decline in cognitive abilities.
A subset of the 190 protein levels (17) were significantly different in people with MCI or Alzheimer's. When those markers were checked against data from 566 people participating in the multicenter Alzheimer's Disease Neuroimaging Initiative, only four markers remained: apolipoprotein E, B-type natriuretic peptide, C-reactive protein and pancreatic polypeptide.
Changes in levels of these four proteins in blood also correlated with measurements from the same patients of the levels of proteins [beta-amyloid] in cerebrospinal fluid that previously have been connected with Alzheimer's. The analysis grouped together people with MCI, who are at high risk of developing Alzheimer's, and full Alzheimer's.
"We were looking for a sensitive signal," says Hu. "MCI has been hypothesized to be an early phase of AD, and sensitive markers that capture the physiological changes in both MCI and AD would be most helpful clinically."
"The specificity of this panel still needs to be determined, since only a small number of patients with non-AD dementias were included," Hu says. "In addition, the differing proportions of patients with MCI in each group make it more difficult to identify MCI- or AD-specific changes."
Neurologists currently diagnose Alzheimer's disease based mainly on clinical symptoms. Additional information can come from PET brain imaging, which tends to be expensive, or analysis of a spinal tap, which can be painful.
"Though a blood test to identify underlying Alzheimer's disease is not quite ready for prime time given today's technology, we now have identified ways to make sure that a test will be reliable," says Hu. "In the meantime, the combination of a clinical exam and cerebrospinal fluid analysis remains the best tool for diagnosis in someone with mild memory or cognitive troubles."
Hu's research began while he was a fellow at the University of Pennsylvania. Collaborators included David Holtzman, MD, from Washington University at St Louis, Leslie Shaw, PhD and John Trojanowski, MD, PhD from the University of Pennsylvania, and Holly Soares, PhD from Bristol Myers Squibb.
The Alzheimer's Disease Neuroimaging Initiative is administered by UCLA, and is supported by the National Institutes of Health and several pharmaceutical companies. Hu's research is supported by the Viretta Brady Discovery Fund.
Reference: W.T. Hu et al. Plasma multianalyte profiling in mild cognitive impairment and Alzheimer disease. Neurology 79, 897-905 (2012).
Kerry Ludlam | EurekAlert!
Cholesterol-lowering drugs may fight infectious disease
22.08.2017 | Duke University
Once invincible superbug squashed by 'superteam' of antibiotics
22.08.2017 | University at Buffalo
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences