Researchers find existing brain cells -- not transplants -- may replenish dead counterparts
Boston, MA -- June 22, 2000 -- Healing a human brain from the inside out was supposed to be impossible. The evolutionary choice for mammals was believed to be between a brain that was fixable and a brain that was too complex to tinker with after it was formed, especially from the inside. Now comes the discovery from a Children's Hospital research group, published today in the journal Nature, that our brain's nerve cells or neurons could one day be induced into healing themselves.
The paper from Jeffrey Macklis, Harvard Medical School associate professor of neurology at Children's Hospital, and his associates Sanjay Magavi and Blair Leavitt, flies in the face of a century of neuroscience conviction that in mammals the brain and particularly the cerebral cortex is incapable of healing itselfa dogma that a series of recent experiments has shaken.
"Somewhere during evolution it was believed," Macklis says, "our brain, unlike the brains of other lower vertebrates, decided it would no longer do self-repair. The assumption has been that because we as mammals build a very complex brain, we don't want to mess around with it. We know now that this view isn't correct."
The Macklis group was able to induce stem cells deep in the cerebral cortex of adult mice to replace damaged neurons. These new neurons grew from already present immature precursor cells into fully formed, connected, and mature replacements. These home grown neurons demonstrate for the first time that the brain can heal itself from the inside out, without transplantation.
This breakthrough in fundamental neural cell biology is a long way from clinical application but Macklis says that if the mechanisms at work here can be understood and controlled, it may open a new avenue someday for treatment of degenerative brain diseases and central nervous system injuries.