Injections of stem cells ease brain ailment in mice

Researchers hope technique might someday help humans


In a possible glimpse at the brain surgery of the future, biologists have partly cured mice of a disease resembling multiple sclerosis by injecting restorative cells into their brains.

The cells migrated all over the brain and took the correct action to repair the neural disease, in this case a lack of the sheath that covers certain nerve cells and helps speed their conduction of electrical signals.

The approach is founded on the use of stem cells, the regenerative cells with which organs renew and repair themselves. Dr. Evan Y. Snyder and his colleagues at Harvard Medical School worked with neural stem cells, the progenitor cells that develop into all of the other specialized cells of the brain.

Snyder said his experiment showed, in principle, that neural stem cells can migrate all over the brain and develop into the right kinds of specialized cells. Hence human neural stem cells might serve to treat diseases that affect the whole brain, such as Alzheimer's and multiple sclerosis.

The subjects of Snyder's study, reported in today's issue of the Proceedings of the National Academy of Science, were "shiverer" mice, so called because they shiver uncontrollably throughout their generally short adult life.

The mice's problem is a mutation in the gene that makes myelin, the material that sheathes the long extensions of certain nerve cells. Because the gene is disrupted, the oligodendrocytes, the special cells that do the cladding, are ineffective.

In his experiment, Snyder injected neural stem cells from a normal mouse into newborn shiverer mice, into the brain region from which the stem cells originate. The new stem cells spread all over the brain, transformed themselves into oligodendrocytes and churned out myelin to wrap around the cells.

The shivering abated in more than half the treated mice, and some seemed fully normal.

For a next step, Snyder plans to repeat his experiment in adult mice, then perhaps with monkeys, and then in an appropriate clinical setting. Snyder envisions a new approach to many brain diseases, based on the use of neural stem cells.

Pub Date: 6/08/99

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