Researchers at the National Institute of Neurological Disorders and Stroke published an article in Science in December 2000 reporting on a very surprising finding — bone marrow injected into mice were able to transform themselves into brain cells.
Bone marrow consists of a couple of different types of stem cells which are the source of blood cells in the body. Scientists knew that neural stem cells can transform themselves into muscle, but the accidental discovery that bone marrow stem cells can transform into neurons was a major surprise.
In fact the researchers weren’t even investigating that possibility in their initial experiments. They had injected mice with a genetically altered form of bone marrow that contained a gene that made the stem cells glow in the dark. The researchers were investigating whether or not the stem cells would convert themselves to muscle cells in the mice.
When they performed the dissection of the mice, however, they were surprised to find the animals’ brains contained neurons that now glowed in the dark. Several other experiments, some involving a second laboratory, were done to confirm that in fact the bone marrow was replacing neurons.
Helen M. Blau, senior author of the Science article, told the Associated Press that, “It may be a repair mechanism that is going all the time at a low level.” The bone marrow probably doesn’t work at a high enough level to repair serious brain damage or disease, but it may be on ongoing way that the body replace dying or defective neurons.
A lot more research will need to be done to better understand what is going on here, and this may never lead directly to any treatment for neurological disorders, but it does add an important piece of the puzzle on how adult stem cells can differentiate into a wide variety of other cells which is of great importance in many current efforts to find treatments for Alzheimer’s, spinal cord injuries, and a whole host of other ailments.
Source:
Mice marrow can net neurons. Associated Press, December 1, 2000.