Discovery: Bone Marrow Cell Can Morph Into Liver, Lung, Gut, Skin, More
A New Rule Book continued...
Sharkis knew that the adult stem cell everyone has been looking for has an interesting property: When placed in the body, it quickly goes back to its home in the bone marrow. So he took bone marrow from a male mouse and injected it into a female mouse whose own marrow had been destroyed by radiation.
After two days, he looked inside bone from the female mouse and found some of the cells he had injected. He then gave 30 new marrow-depleted female mice a transplant with just one of these male cells. The transplant rescued five of the animals.
The male cells divided quickly and repopulated the females' marrow. They also turned into cells that, to a greater or lesser extent, repopulated the animals' lungs, liver, skin, and digestive tract. The greatest repopulation was seen in the lung -- possibly because the cells were repairing damage caused by the original radiation.
"This is the final nail in the coffin of the idea that cells have such rigid restrictions on what they can do," Theise says. "A new paradigm is required to accommodate this data."
If these versatile stem cells exist in mice, they should exist in humans. But if we already have them, why don't they repair damaged organs?
Probably they do. But researchers hope that if they can figure out what makes these cells tick, they can make them do even more repair work.
"Maybe we can get these cells to go to the damaged organs and repair them -- that's the trick," Theise says. "They are doing this as we speak, but in some cases they don't accomplish the job. If we can figure out what the mechanisms are that make them do this, we could stimulate the body to repair itself in a way it wouldn't otherwise."
For people whose organs are damaged too much for repair, the new cells could be used as part of an artificial organ. And the possibilities are enormous for people with genetic diseases.
"You could take the cell from a patient, put in a gene or correct a defective one, and then put it back in the patient," Theise speculates. "Gradually, through normal cell turnover, you could correct genetic defects in one or more organs."
Not the End of Fetal-Cell Research
Even though the new adult cells can do things once thought impossible, it doesn't mean there isn't more to learn from research into the ultimate stem cell: the embryonic cell.
"I don't want our data to be used as an argument against continuing fetal cell research," Krause says. "I don't think you will find a single person in our field who will say we are finished with this kind of research. This is a beginning -- an exciting beginning, but a beginning all the same."