Scientists were able to detect that RPE cells indeed appear to be naturally replenished in the test animals by transplanting bone marrow cells from normal male mice into albino females with two different types of acute RPE injury.
Bone marrow contains stem cells, which have the extraordinary abilities to home in on injuries and possibly regenerate other cell types in the body. In this case, the cells were transplanted to confirm that bone marrow does regenerate the injured RPE. It was easier to track male, pigment-producing cells in female, albino recipients, Harris said.
Chemical and microscopic analysis showed the cells that traveled to the injury site and transformed into RPE indeed had male genetic characteristics. Furthermore, these cells were capable of producing pigment - a colorful indication that the RPE could only have arisen from the donor bone marrow stem cells.
"We did not use a direct model of age-related macular degeneration," Scott said. "But we now know that when RPE is injured, it can be replaced in certain situations. It gives us growth factors, cell pathways and other different places to look at to find reasons why the disease is occurring."
Researchers want to discover ways to mobilize an elderly patient's own cells to travel to the injury site to make repairs.
"The dogma has been that we're born with a fixed amount of RPE, but there is growing evidence retinal progenitor cells exist in the adult," said Lawrence Rizzolo, Ph.D., a Yale University associate prof
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Contact: John D. Pastor
jpastor@vpha.health.ufl.edu
352-273-5815
University of Florida
8-Jun-2006