[tabi] Fw: Scientists program blood stem cells to become vision cells
- From: "Laurie Davis" <davisllb@xxxxxxxxxxxxxx>
- To: <tabi@xxxxxxxxxxxxx>
- Date: Tue, 4 Aug 2009 17:18:41 -0400
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Subbject: Scientists program blood stem cells to become vision cells
Scientists program blood stem cells to become vision cells
ScienceDaily (July 30, 2009) University of Florida researchers were able to
program bone marrow stem cells to repair damaged retinas in mice, suggesting a
potential treatment for one of the most common causes of vision loss in older
people.
The success in repairing a damaged layer of retinal cells in mice implies that
blood stem cells taken from bone marrow can be programmed to restore a variety
of cells and tissues, including ones involved in cardiovascular disorders such
as atherosclerosis and coronary artery disease.
"To our knowledge, this is the first report using targeted gene manipulation to
specifically program an adult stem cell to become a new cell type," said Maria
B. Grant, M.D., a professor of pharmacology and therapeutics at UF's College of
Medicine. "Although we used genes, we also suggest you can do the same thing
with drugs but ultimately you would not give the drugs to the patient, you
would give the drugs to their cells. Take the cells out, activate certain
chemical pathways, and put the cells back into the patient."
In a paper slated to appear in the September issue of the journal Molecular
Therapy, scientists describe how they used a virus carrying a gene that gently
pushed cultured adult stem cells from mice toward a fate as retinal cells. Only
after the stem cells were reintroduced into the mice did they completely
transform into the desired type of vision cells, apparently taking
environmental cues from the damaged retinas.
After studying the cell-transformation process, scientists were able to bypass
the gene manipulation step entirely and instead use chemical compounds that
mirrored environmental conditions in the body, thus pointing the stem cells
toward their ultimate identities as vision cells.
"First we were able to show you can overexpress a protein unique to a retinal
cell type and trick the stem cell into thinking it is that kind of cell," said
Grant, who collaborated with Edward Scott, Ph.D., the director of the Program
in Stem Cell Biology and Regenerative Medicine at UF's McKnight Brain
Institute. "As we proceeded, we found we could activate the stem cells by
mimicking the body's natural signaling channels with chemicals. This implies a
whole new field of stem cell research that uses drug manipulation rather than
genetic manipulation to send these immature cells along new pathways."
Scientists chose to build retinal pigment epithelial cells, which form the
outer barrier of the retina. In addition to being very specialized and easy to
identify, RPE cells are faulty in many retinal diseases, including age-related
macular degeneration, which affects nearly 2 million people in the United
States, and some forms of blindness related to diabetes.
"This work applies to 85 percent of patients who have age-related macular
degeneration," Grant said. "There are no therapies for this devastating
disease."
The work was supported by the National Eye Institute. Researchers removed blood
stem cells from the bone marrow of mice, modified the cells in cultures, and
injected them back into the animals' circulatory systems. From there, the stem
cells were able to home in on the eye injury and become retinal cells.
At 28 days after receiving the modified stem cells, mice that had previously
demonstrated no retinal function were no different than normal mice in
electrical measures of their response to light.
Grant and UF have patented some technology involved in the research.
http://www.sciencedaily.com/releases/2009/07/090731085823.htm
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