Navigation Links
Multiple research teams unable to confirm high-profile Alzheimer's study
Date:5/24/2013

Teams of highly respected Alzheimer's researchers failed to replicate what appeared to be breakthrough results for the treatment of this brain disease when they were published last year in the journal Science.

Those results, presented online Feb. 9, 2012, suggested that the drug bexarotene (marketed as Targretin) could rapidly reverse the buildup of beta amyloid plaques (Aβ) a pathological hallmark of Alzheimer's disease in the brains of mice. According to the authors of the 2012 report, drug treatment quickly removed most of the plaques and brought rapid reversal of the pathological, cognitive and memory deficits related to the onset of Alzheimer's.

However, the new reports from extensive and carefully controlled studies did not show any reduction in the number of plaques or total area occupied by the plaques during or after treatment. These results are described in three "technical comments" one of which comes from researchers at the University of Chicago, Northwestern University, Massachusetts General Hospital, Washington University in St Louis and University of Tubingen in Germany to be published in the May 24, 2013, issue of Science.

"The drug has no impact on plaque burden in three strains that exhibit Aβ amyloidosis," according to that group's comment. "We have failed to support earlier findings by Cramer et al that Targretin is efficacious in reducing plaque burden in transgenic mouse models of cerebral Aβ deposition."

Comment co-author Sangram Sisodia, PhD, professor of neurosciences at the University of Chicago, said he and his colleagues were curious about the initial report in 2012.

"We were surprised and excited, even stunned, when we first saw these results presented at a small conference," said Sisodia. "The mechanism of action made some sense, but the assertion that they could reduce the areas of plaque by 50 percent within three days, and by 75 percent in two weeks, seemed too good to be true."

"We all went back to our labs and tried to confirm these promising findings," Sisodia added. "We repeated the initial experiments a standard process in science. Combined results are really important in this field. None of us found anything like what they described in the 2012 paper."

The researchers found no effects on plaque burden in three different strains of mice that were treated with bexarotene.

The discrepancy, besides being disappointing, also raises concerns about patient safety. The Food and Drug Administration approved bexarotene in December 1999 for a very specific use: treatment of refractory cutaneous T-cell lymphoma, a type of skin cancer. Once approved, the drug became legally available by prescription for "off-label" uses as well.

"Anecdotally, we have all heard that physicians are treating their Alzheimer's patients with bexarotene, a cancer drug with severe side effects," said co-author Robert Vassar, PhD, professor of cell and molecular biology at Northwestern University Feinberg School of Medicine. "This practice should be ended immediately, given the failure of three independent research groups to replicate the plaque-lowering effects of bexarotene."

Bexarotene has never been tested as a treatment for Alzheimer's disease in humans, not even to determine the optimal dose or duration of treatment. This drug has significant side effects, including major blood-lipid abnormalities, pancreatitis, liver function test abnormalities, thyroid axis alterations, leucopenia, headaches, fatigue, weight gain, depression, nausea, vomiting, constipation and rash.

The two other technical comments came from research teams led by Kevin Felsenstein, Todd Golde, David Borchelt and colleagues at the University of Florida and by Bart DeStrooper and colleagues at the University of Leuven, Belgium.

There is no cure or effective treatment for Alzheimer's disease, which is a progressive type of dementia that occurs when nerve cells in the brain die. When Alzheimer's was first identified in 1906, it was considered a rare disorder. Today, Alzheimer's is the most common cause of dementia. An estimated 5.3 million Americans have the disease.


'/>"/>

Contact: John Easton
john.easton@uchospitals.edu
773-795-5225
University of Chicago Medical Center
Source:Eurekalert

Related medicine news :

1. Multiple System Atrophy (MSA) Research Grant Program Announced
2. Multiple Head Injuries Raise Soldiers Suicide Risk, Study Finds
3. Imprelis Lawsuit Filed by Wright & Schulte LLC on Behalf of Multiple Lawn Care Companies and Property Owners Who Allege Imprelis Use Caused Extensive Tree Damage
4. Dr. Gary M. Levin's Multiple Sclerosis Treatment Review and MS Research Revealed by SclerosisTreatment.com
5. Weill Cornell Medical School Teams with MediGait to Get the Elderly, Sufferers of Parkinson’s and Multiple Sclerosis “Back on their Feet”
6. Imprelis Lawsuit Representing Multiple Property Owners Alleging Imprelis Seriously Damaged Their Trees and Other Plant Life Filed By Wright & Schulte
7. Multiple Vaginal Mesh Lawsuits Filed Against Ethicon, Inc. on Behalf of Women Seriously Injured Allegedly Due to Vaginal Mesh Sling Defects, Reports Wright & Schulte
8. Class Action Imprelis Lawsuit Filed on Behalf of Multiple Property Owners Who Allege Imprelis Use Caused Extensive Tree Damage and Death, Reports Wright & Schulte
9. Shrinkage of Brain Region May Signal Onset of Multiple Sclerosis
10. Atrophy in key region of brain associated with multiple sclerosis
11. Multiple Imprelis Lawsuits Filed by Wright & Schulte Alleging Imprelis Use Resulted in Extensive Tree Damage and Death
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/27/2016)... , ... June 27, 2016 , ... ... edge technology to revolutionize the emergency ambulance transport experience for the millions of ... of how Uber has disrupted the taxi industry through the use of technology. ...
(Date:6/26/2016)... , ... June 26, 2016 , ... Pixel Film Studios ... X. , "Film editors can give their videos a whole new perspective by using ... - CEO of Pixel Film Studios. , ProSlice Levels contains over 30 Different ...
(Date:6/25/2016)... D.C. (PRWEB) , ... June 25, 2016 , ... ... discuss health policy issues and applications at AcademyHealth’s Annual Research Meeting June 26-28, ... their work on several important health care topics including advance care planning, healthcare ...
(Date:6/25/2016)... ... June 25, 2016 , ... First Choice Emergency Room , the ... Ogunleye, as the Medical Director of its new Mesquite-Samuell Farm facility. , “We ... new Mesquite location,” said Dr. James M. Muzzarelli, Executive Medical Director of First Choice ...
(Date:6/25/2016)... ... ... Conventional wisdom preaches the benefits of moderation, whether it’s a matter of indulgence ... high can result in disappointment, perhaps even self-loathing. However, those who set the bar ... from PsychTests.com reveals that behind the tendency to set low expectations is ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... SOUTH SAN FRANCISCO, Calif. , June 24, ... GBT ), a biopharmaceutical company developing novel ... with significant unmet needs, today announced the closing ... 6,400,000 shares of common stock, at the public ... the shares in the offering were offered by ...
(Date:6/24/2016)... , June 24, 2016 The Academy of ... recommendations that would allow biopharmaceutical companies to ... entities that make formulary and coverage decisions, a move ... of new medicines. The recommendations address restrictions ... appear on the drug label, a prohibition that hinders ...
(Date:6/24/2016)... -- According to a new market research ... Safety Pen Needles), Needle Length (4mm, 5mm, 6mm, 8mm, ... Purchase (Retail, Non-Retail) - Trends & Global Forecasts to ... for the forecast period of 2016 to 2021. This ... 2021 from USD 1.65 Billion in 2016, growing at ...
Breaking Medicine Technology: