- The Washington Times - Monday, July 29, 2002

Stem cells taken from bone marrow can grow new blood vessels in the eyes of mice, a development researchers say raises the chance of treating some diseases that often lead to blindness in humans.
In tests in mice, injected stem cells became incorporated into the eye's structure and formed new blood vessels.
If the process turns out to work in humans, the scientists hope to use it to treat eye diseases affecting the blood vessels in the retina. They include diabetic retinopathy and age-related macular degeneration, two leading causes of blindness.
The stem cells in question are "adult" cells from bone marrow available from living donors; they need not be harvested from human embryos, a process that kills the embryo.
Dr. Martin Friedlander, who headed the research team at the Scripps Research Institute in La Jolla, Calif., said the process may be used to rescue sick blood vessels or, in a modified form, to inhibit the growth of abnormal vessels in the eye.
His research will be published in the September issue of the journal Nature Medicine.
Peter A. Dudley, director of the retinal diseases program the National Eye Institute, said it is "extremely interesting" that the team was able to take certain precursor stem cells that can form blood vessels and then target them.
He said it seems reasonable this could lead to human treatments, but he cautions that the work involves only mice and that many details need to be worked out before researchers move on to humans.
Dr. John S. Penn, who teaches ophthalmology at Vanderbilt University, said the work adds to the fundamental understanding of biology, calling the finding that the cells can home in on specific parts of the eye "pretty cool stuff."
He also cautioned that the work is in mice, so much more work needs to be done before it can be applied to humans.
Stem cells can differentiate into many different cells depending on what is needed. Dr. Friedlander's team used a type of stem cell called an endothelial precursor cell taken from mouse bone marrow.
When these cells were injected into the eyes of mice, they attached to cells in the retina called astrocytes and then formed new blood vessels.
"What's exciting about this, and surprising to us, is they don't target mature vessels; they go where vessels are going to form," Dr. Friedlander said.
Newborn mice, for example, do not have blood vessels in their retinas but have astrocytes forming a sort of template for future vessels, Dr. Friedlander explained.
In adult mice, he said, if the retina is injured, it encourages the development of astrocytes. By injecting the stem cells, the researchers can help stabilize a degenerating blood vessel system.
Dr. Friedlander said he was "flabbergasted" at the improvement when the stem cells were injected into the eyes of a type of mouse with eye degeneration, which usually causes the animal to go blind within 30 days of birth.

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