A Way to Slow Parkinson's?
Blocking Specific Form of a Brain Chemical Could Slow Brain Cell Loss, 
Researchers Find 
By Daniel DeNoon
 WebMD Medical News   Reviewed By Louise Chang, MD
 on Tuesday, September 12, 2006 

 Nicotine Slows Parkinson's Disease 

 
  Sept. 12, 2006 -- Blocking a specific form of a brain chemical slows brain 
cell loss in an animal model of Parkinson's disease, Texas researchers 
report.
In the animal model, the researchers found they could slow the death of 
affected brain cells by about half by blocking the chemical, called soluble 
TNF.
The finding offers a target for new drugs that could slow the progression of 
the debilitating and deadly disease. And it may apply to Alzheimer's disease 
as well, suggest University of Texas Southwestern Medical Center researchers 
Melissa K. McCoy, Malú G. Tansey, PhD, and colleagues.
The finding "may unveil opportunities for development of new … therapeutics to 
treat human neurodegenerative diseases like Parkinson's disease and 
Alzheimer's disease," McCoy and colleagues say.
The researchers report their study in the Sept. 13 issue of The Journal of 
Neuroscience.
Parkinson's Culprit Found?
Parkinson's happens when about 80% of a specific kind of brain cell 
mysteriously dies off. McCoy and colleagues note that this seems to involve 
one of the body's most basic immune responses -- inflammation.
Messenger chemicals trigger this process. One of those chemical messengers is 
tumor necrosis factor, or TNF.
You may have read about TNF before. It's involved in the haywire immune 
responses that cause rheumatoid arthritis.
The UTSW researchers decided to look at a specific form of TNF called soluble 
TNF. That's because the kind of brain cells that die off during Parkinson's 
disease are highly sensitive to that brain chemical.
Sure enough, in an animal model of Parkinson's disease, they found that by 
blocking soluble TNF, the rate of brain cell death could be about cut in 
half.
That, they suggest, would be enough to significantly slow the inexorable, 
deadly progression of Parkinson's disease.
Current arthritis drugs Enbrel and Remicade block TNF. But they block a form 
of the chemical important to immune function and infection resistance.
For Parkinson's disease, McCoy and colleagues suggest a drug that specifically 
blocks soluble TNF would be safer.
There's also evidence from mice studies that TNF signaling may be important in 
Alzheimer's disease, too. McCoy and colleagues say a drug that blocks soluble 
TNF might kill two birds with one stone.
Blocking soluble TNF does not stop the death of important brain cells -- it 
only slows the process. But the researchers say this could be enough to make 
a major impact.
"A reduction of [brain-cell] death by 50% with delivery of [TNF-blockers] into 
the central nervous system would have a significant and positive impact on 
delaying progression of [brain cell] loss in individuals with Parkinson's 
disease, should these results in animal models be realized in clinical 
trials," they say.
SOURCES: McCoy, M. The Journal of Neuroscience, Sept. 13, 2006; vol 26: draft 
copy received in advance of publication.

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