Bone marrow may restore cells lost in vision diseasesJune 09, 2006UF finding could lead to approaches to treat macular degeneration GAINESVILLE, Fla.—University of Florida scientists conducting experiments with mice have found evidence that the body naturally replenishes small amounts of cells in the eye essential for healthy vision. The finding may shatter the belief that a cell layer vital for eyesight called the retinal pigment epithelium, or RPE, is a nonrenewable resource, say researchers writing in a recent issue of Investigative Ophthalmology & Visual Science. RPE plays a vital role in our visual health by forming the outer barrier of the retina and supporting the function of cells that receive light. Damage to RPE is present in many diseases of the retina, including age-related macular degeneration, which affects more than 1.75 million people in the United States. With evidence that the body does indeed regenerate these cells in small amounts, scientists can focus on ways to accelerate natural healing processes to treat sight-robbing injuries or diseases. "What this tells us is for problems such as age-related macular degeneration, we should be able to harvest stem cells to help repair the damage," said senior author Edward Scott, Ph.D., a professor of molecular genetics at the UF Shands Cancer Center and director of the Program in Stem Cell Biology and Regenerative Medicine at UF's College of Medicine. "The question is whether we can do it in a patient." Scientists widely believe that RPE is a finite resource. The same belief used to be held about brain cells—people who suffered from trauma, stroke or disease formerly faced no hope of growing new cells to replace dead ones. Then, in the late 1990s, when scientists began to report findings of brain cell growth in humans and monkeys later in life, focus turned toward understanding the mechanisms to regenerate cells in the brain. Now, UF researchers believe it may be possible to also grow new cells in the retina to replace cells lost to injury or disease. "In people, retinal pigment epithelium can become damaged with age," said Jeffrey Harris, a graduate student in the department of molecular cell biology in UF's College of Medicine and first author of the paper. "Factors like smoking and diet also come into play. The problem is without these cells, the rods and cones—our primary cells for vision—die. If we can regenerate the retinal pigment epithelium, it could make a big difference in our visual health." 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 professor of anatomy and experimental surgery and of ophthalmology and visual science who was not involved in the research. "To derive cells of neuronal lineage from cells of bone-marrow lineage is significant, if the finding stands up to the test of time. Compared to RPE transplantation, there are a lot of advantages if someone's own bone marrow could supply the cells, because it's a ready source and the cells would not be rejected by the patient. Further, if bone-marrow progenitors circulating in the blood could be attracted to sites of disease, surgery could be avoided." University of Florida |
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| Related Bone Marrow Current Events and Bone Marrow News Articles New stem cell technology developed at Hebrew University A novel technology involving use of stem cells, developed by Hebrew University of Jerusalem researchers, has been applied to provide better and rapid healing for patients suffering from complicated bone fractures. Physician-scientist proves stem cells heal lungs of newborn animals Dr. Bernard Thébaud lives in two very different worlds. As a specialist in the Stollery Children's Hospital's Neonatal Intensive Care Unit at the Royal Alexandra Hospital, he cares for tiny babies, many of whom struggle for breath after being born weeks before they are due. Too much physical activity may lead to arthritis Middle-aged men and women who engage in high levels of physical activity may be unknowingly causing damage to their knees and increasing their risk for osteoarthritis, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA). Gene mismatch influences success of bone marrow transplants A commonly inherited gene deletion can increase the likelihood of immune complications following bone marrow transplantation, an international team of researchers reports in the November 22 advance online issue of Nature Genetics. New cancer target for non-Hodgkin's lymphoma Physician-scientists from Weill Cornell Medical College have discovered a molecular mechanism that may prove to be a powerful target for the treatment of non-Hodgkin's lymphoma, a type of cancer that affects lymphocytes, or white blood cells. Bone Implant Offers Hope for Skull Deformities A synthetic bone matrix offers hope for babies born with craniosynostosis, a condition that causes the plates in the skull to fuse too soon. U of M researchers find 2 units of umbilical cord blood reduce risk of leukemia recurrence A new study from the Masonic Cancer Center, University of Minnesota shows that patients who have acute leukemia and are transplanted with two units of umbilical cord blood (UCB) have significantly reduced risk of the disease returning. Scientists successfully reprogram blood cells Researchers have transplanted genetically modified hematopoietic stem cells into mice so that their developing red blood cells produce a critical lysosomal enzyme -preventing or reducing organ and central nervous system damage from the often-fatal genetic disorder Hurler's syndrome. Immune therapy can protect against or treat later lymphoma Specially developed immune system cells that target the common Epstein-Barr virus can protect immune-suppressed bone marrow transplant recipients against lymph system disease and cancers that arise from the viral infection. Stem cell therapy may offer hope for acute lung injury Researchers at the University of Illinois at Chicago College of Medicine have shown that adult stem cells from bone marrow can prevent acute lung injury in a mouse model of the disease. More Bone Marrow Current Events and Bone Marrow News Articles |
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