Navigation Links
Brain damage found in cognitively normal people with Alzheimer's marker

March 10, 2009 -- Researchers at Washington University School of Medicine in St. Louis have linked a potential indicator of Alzheimer's disease to brain damage in humans with no signs of mental impairment.

Although their cognitive and neurological assessments were normal, study participants with lower levels of a substance known as amyloid beta 42 (A-beta 42) in their cerebrospinal fluid (CSF) had reduced whole brain volumes, suggesting that Alzheimer's changes might already be damaging their brains. Scientists previously showed that low CSF levels of A-beta 42 mark the presence of amyloid deposition in the brain, a key diagnostic marker of the amyloid plaques that characterize Alzheimer's disease.

Evidence is mounting that Alzheimer's harms the brain for many years before physicians and family members can detect symptoms, and this has led many to conclude that successful Alzheimer's treatments may only be possible if scientists find ways to identify pre-symptomatic sufferers.

The results are an encouraging sign that this search for new indicators, known as antecedent biomarkers, may be succeeding, according to senior author David M. Holtzman, M.D., the Andrew and Gretchen Jones Professor and chair of the Department of Neurology at the School of Medicine and neurologist-in-chief at Barnes-Jewish Hospital.

"We still need to confirm with long-term follow-up studies that subjects with this biomarker and brain damage go on to develop the cognitive changes characteristic of Alzheimer's," says Holtzman. "For now, the evidence we've uncovered further proves that identification and treatment prior to the start of the symptoms of Alzheimer's disease are likely going to be essential to preventing irreversible brain injury."

The results were published in the February issue of Annals of Neurology.

A-beta 42 is a protein fragment that clumps together in the brain to form the plaques that have long been the diagnostic hallmark of the disease. In an earlier study, the same Washington University researchers showed that when A-beta 42 decreases in CSF, it begins to build up in the brain.

"The new results show that something associated with amyloid deposition in the brain − either the amyloid itself or some toxic product of it − is causing brain damage in people who are still cognitively normal," says Holtzman.

For the study, led by Anne Fagan, Ph.D., research associate professor of neurology, scientists analyzed CSF samples and brain scans of two groups of subjects at the university's Alzheimer's Disease Research Center. The first group of 29 volunteers had very mild cognitive impairment; the remaining 69 volunteers were cognitively normal. Their ages ranged from 60 to 91.

Researchers analyzed CSF samples and took magnetic resonance imaging (MRI) scans of subjects' brains. They used a computer program to analyze the MRI scans and determine whole brain volume, a measurement of the amount of space taken up by a patient's gray and white matter minus the CSF fluid circulating in the skull.

Participants with normal levels of A-beta 42 in their CSF had whole brain volumes within expected ranges. But in both the cognitively impaired subjects and in cognitively normal volunteers with decreased CSF A-beta 42, the size of the brain was smaller.

In addition to A-beta 42, researchers analyzed CSF levels of a family of proteins called tau proteins. These proteins are a component of structures called neurofibrillary tangles that increase as Alzheimer's disease progresses. Scientists believe increased levels of tangles in the brain lead to increased CSF tau levels.

Researchers found CSF tau levels did not increase until subjects became mentally impaired.

"We've thought for some time that in Alzheimer's disease, amyloid builds up first followed by an increase in tangle accumulation," Holtzman says. "This is some of the first evidence in living people that this idea may be right: large scale changes in amyloid seem to precede large scale changes in tau, which are then linked to the onset of clinical dementia symptoms."

Researchers will follow cognitively normal subjects with reduced CSF amyloid levels and brain volumes to see if they eventually become demented, potentially confirming A-beta 42 as an antecedent biomarker for Alzheimer's disease. They continue to look for additional Alzheimer's biomarkers in CSF samples and brain scans.


Contact: Michael C. Purdy
Washington University School of Medicine

Related medicine news :

1. UH research team developing new noninvasive brain-mapping technology
2. Combo Treatment for Aggressive Brain Tumor May Lengthen Life
3. Think About It. Barry Spiegelman Memorial Golf Classic Benefits Brain Cancer Research
4. Brain tumors: New therapy surprisingly successful
5. Brain Tumor Drug May Help Spur Cancers Return
6. Brain tumor treatment may increase number of cancer stem-like cells
7. European Commission and United States Food and Drug Administration (FDA) Both Approve New Options for Patients With Certain Primary Brain Tumors
8. Now Hear This: Brain Fitness Exercises Improve Listening
9. Nearly 1.4 Million Sustain Traumatic Brain Injuries Each Year
10. National Council on Disability Says More Needs to be Done for Service Members and Veterans With Post Traumatic Stress Disorder and Traumatic Brain Injury
11. Brain Adapts to Age-Related Eye Disease
Post Your Comments:
(Date:11/27/2015)... CO (PRWEB) , ... November 27, 2015 , ... According ... cities are not changing the way that they are handling security in light of ... police and security presence in an attempt to stop an attack from reaching U.S. ...
(Date:11/27/2015)... County, CA (PRWEB) , ... November 27, 2015 , ... ... season , The company is offering customers 10% off of their purchase of lice ... any treatment at full price. According to a company spokesperson. “Finding lice is a ...
(Date:11/27/2015)... ... November 27, 2015 , ... Intellitec ... Dynamics SL User Group (MSDSLUG). Recognized as Microsoft’s official group for end users ... Dynamics SL software users, partners, industry experts and representatives. Intellitec Solutions’ membership status ...
(Date:11/27/2015)... IL (PRWEB) , ... November 27, 2015 , ... ... of the largest, most successful and prominent nonprofit healthcare organizations in the country. ... governance involvement with various organizations, and helped advance the healthcare industry as a ...
(Date:11/26/2015)... ... ... Inevitably when people think Thanksgiving, they also think Holiday sales and start ... and Cyber Monday massage chair sales to receive the best pricing on ... find the best massage chair deals, they can see all of the coupons in ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... , November 26, 2015 /PRNewswire/ ... --> adds "Global ... and "Investigation Report on China Repaglinide ... 2021 forecasts data and information to ... . --> ...
(Date:11/26/2015)... 26, 2015 ... "Radioimmunoassay Market by Type (Reagents & ... Academics, Clinical Diagnostic Labs), Application (Research, Clinical ... 2020" report to their offering. ... addition of the "Radioimmunoassay Market by ...
(Date:11/25/2015)...  The total global healthcare industry is expected to grow ... Latin America has the highest projected growth at ... Japan ), is second with growth projected at 11.5%. ... healthcare expenditure. In 2013-2014, total government funded healthcare was nearly ... to 41.2% in 2013-2014. In real terms, out of pocket ...
Breaking Medicine Technology: