Bone marrow produces cells that not only help fight infection but also permanently heal wounds, according to research at the University of Washington. Previously, researchers had not known that bone marrow contributed to the development of new skin in wounds.
The findings will be published in the Sept. 3 issue of Stem Cells.
"Wounds may not heal the way we thought they did," says Dr. Richard Ikeda, a biochemist at the National Institute of General Medical Sciences, one of the National Institutes of Health, which supported the work. "This study shows that bone marrow stem cells, in addition to cells from the surrounding tissue, may actually contribute to the healing process. If this is the case, it could lead to completely new ways of treating serious wounds."
When a body is wounded, the body immediately tries to form a clot in order to stop the bleeding. The seal is formed with the help of cells that circulate in your blood all the time and are on the spot immediately. The body also has an inflammatory response: signals direct white blood cells to the area of the wound. The white blood cells arrive to fight off foreign bacteria and infection. This inflammatory response is responsible for the red area around a wound. The inflammatory response goes away within a few days to a week, assuming there is no continued infection.
"Scientists have long assumed that once the inflammatory response concludes, the white blood cells mostly either then die or go into circulation in the bloodstream. We did not know, until now, that the bone marrow-derived cells go on to become a significant part of the new skin," said Dr. Frank Isik, professor of surgery at the University of Washington. "We've known that bone marrow cells are involved in wound healing and inflammation -- now we have data that shows bone marrow cells are involved in normal skin maintenance, in maintaining the matrix environment and integrity of the skin."
Bone marrow has been studied for a number of purposes in recent years because it is rich in stem cells -- cells that can go on to become many different kinds of cells. In order to conduct this research, Isik and colleagues obtained a strain of mice whose bodies glow green under fluorescent light. The researchers removed bone marrow from the mice and then performed a stem cell transplant into a genetically identical strain of normal mice, whose cells do not glow green. Afterward, only the bone marrow of the transplanted mice glowed green inside the bodies of the mice, allowing researchers to track the bone marrow cells throughout the body. Researchers found green cells throughout the body, but observed that the highest concentration of bone marrow cells was in normal skin.