MONTREAL — Dr. Freda Miller has a vision. It is that someday she could take a bit of someone's skin and transform its "blank slate" stem cells into brain tissue to alleviate that person's Parkinson's symptoms, or pancreatic cells to cure a patient's diabetes. (No cloning necessary.)
Miller and her research team at McGill University's Montreal Neurological Institute unveiled the first step toward that vision last week when they announced that they have discovered stem cells deep in the skin of rats and humans that can become fat, muscle or even brain cells.
The discovery, detailed in the September issue of the journal Nature Cell Biology, is a significant step in research showing that stem cells of adults--not just those found in embryos--can change into many types of tissue. If adult stem cells can be used to treat diseases, they might provide a way to sidestep the moral dilemma of whether a tiny cluster of cells from an embryo represents human life. President Bush grappled with that question this month in deciding to limit federal funding for embryonic stem cell research.
As potentially valuable as it is politically charged, stem cell research is one of the fastest-moving areas in molecular biology. A few years ago, scientists thought that adult stem cells could change only into the same class of tissue as their place of origin. Only stem cells found in the brain, according to this reasoning, could become neural cells, while only those found in bone marrow could help make blood.
In the past year and a half, however, studies have shown that these powerful cells can be coaxed into quite different fates. Stem cells found in the brain can be changed into muscle, and those in bone marrow can turn into liver cells. Unlike their embryonic counterparts, though, adult stem cells are painful to harvest and difficult to divide, and their cell lines--the sets, or colonies, derived from them--are generally short-lived.
But the stem cells found at McGill, which seem to be exceptionally versatile, are easy to generate and simple to collect--the practical beauty of the discovery is that it is only skin deep. Miller's study is the first to claim that a single adult stem cell can give rise to two of three of the basic classes of cells in the body. The McGill lab is working to confirm that it can generate cells for all three, and preliminary results are encouraging, Miller says.
