MULTIPLE sclerosis begins with the death of brain cells that produce the insulating myelin sheath around nerve cells, not with an immune attack on the sheath, as most researchers believe. That鈥檚 the conclusion of a study of brain tissue from 300 MS sufferers by John Prineas and Michael Barnett of the University of Sydney, Australia.
Their findings back the view that the reason for the lack of progress in this field is that most MS research is done on mice with a disease that is actually quite different (New 杏吧原创, 16 November 2002, p 12).
The latest work began after Prineas examined the brain of a 14-year-old girl who had died 17 hours into an MS relapse. He found no signs of an immune attack, and the myelin was intact. But oligodendrocytes, the cells that produce the insulating myelin sheath, were dying.
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Studies of other patients who had died in the early stages of MS revealed the same thing, the pair report in Annals of Neurology online. They conclude that MS starts with the death of oligodendrocytes. Immune cells then move in to clean up the debris, stripping nerve cells of myelin at the same time. Brain cells without myelin can no longer conduct impulses properly.
This raises the question of what is triggering the death of oligodendrocytes. 鈥淭he pattern of death that we observed provides little clue to the cause,鈥� Prineas says.