Fwd: [S-A] New Data Challenges Understanding of MS

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" Misty L. Trepke "

Sat, 06 Mar 2004 04:43:33 -0000

[s-A] New Data Challenges Understanding of MS

 

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Misty L. Trepke

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New Data Challenge Theories Of Multiple

Sclerosis

 

http://www.sciencedaily.com/releases/2004/02/040223075914.htm

 

Source: American Neurological Association

2004-02-23

URL:

http://www.sciencedaily.com/releases/2004/02/040223075914.htm

 

 

New Data Challenge Theories Of Multiple Sclerosis

A new view of multiple sclerosis (MS) may arise from the first

extensive study of brain tissue from the earliest hours during a

bout of the disease. The results, published February 23, 2004, in

the advance on-line edition of the Annals of Neurology, suggest that

the earliest event is not, as previously believed, a misguided

immune system attack on a brain substance called myelin.

 

Instead, the first event appears to be the death of the brain cells

that produce myelin, triggering a subsequent immune system mop-up

operation to clean up the cells and the myelin, said author John W.

Prineas, MBBS, of the University of Sydney in Australia.

 

Multiple sclerosis is an enigmatic disorder of the nerve fibers of

the brain and spinal cord. Scarring (sclerosis) replaces myelin,

which normally insulates the nerves from damage and speeds

electrical conduction through the fibers.

 

Depending on which nerve fibers are hindered, patients can

experience problems ranging from weakness and clumsiness to

numbness, visual disturbances, and even emotional and intellectual

alterations. In some patients, MS manifests itself in cycles of

relapse and remission; in other patients, the disease may progress

to a stage of severe debilitation, either slowly or rapidly.

 

According to Prineas, the study he conducted with coauthor Michael

H. Barnett, MBBS, began several years ago while he was working at

the New Jersey Medical School in Newark. A fellow neuropathologist

in Manhattan asked whether Prineas and his colleagues would be

interested in examining brain tissue from a 14-year-old girl who

died unexpectedly 17 hours into a relapse.

 

Sudden death can occur in MS if the damage (or lesion) occurs in

parts of the brain that control vital functions such as breathing

and blood circulation.

 

" This patient proved to be unique in the history of multiple

sclerosis in that there was lesion available for study that was less

than a day old, " said Prineas.

 

According to the dominant theory of MS, when the researchers

examined the hours-old lesion, they should have found the beginnings

of an immune system attack.

 

But Prineas and Barnett noticed that the myelin in the lesion was

still intact, and there was no evidence that the typical armada of

immune system cells and molecules had moved into the area yet.

Instead, oligodendrocytes cells, which produce the myelin, were

dying. Myelin is, in fact, an extension of oligodendrocytes that

wraps itself around nearby nerve fibers.

 

" This encouraged us to re-examine other early MS cases in our brain

bank, " said Prineas. " Similar lesions, albeit extremely rare, were

identified in a number of other early MS cases, which allowed us to

conclude that the changes observed probably occur at the onset of

any typical new lesion. "

 

The results could have significant consequences for MS research,

much of which is focused on understanding why the immune system

attacks myelin. The focus may have to shift to understanding why the

myelin-producing cells begin to die.

 

" The important point, at this stage of our investigation, seems to

be that we have no laboratory model for this sort of pathology, "

said Prineas.

 

The Annals of Neurology, the preeminent neurological journal

worldwide, is published by the American Neurological Association,

the world's oldest and most prestigious neurological association.

The 1,400 members of the ANA--selected from among the most respected

academic neurologists and neuroscientists in North America and other

countries--are devoted to furthering the understanding and treatment

of nervous system disorders. For more information, visit

http://www.aneuroa.org.

 

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