Navigation Links
Eye Cells Believed to Be Retinal Stem Cells Are Misidentified
Date:3/30/2009

St. Jude study findings suggest that therapies to restore vision in people with retinal degeneration should emphasize the use of other types of stem cells

MEMPHIS, Tenn., March 30 /PRNewswire-USNewswire/ -- Cells isolated from the eye that many scientists believed were retinal stem cells are, in fact, normal adult cells, investigators at St. Jude Children's Research Hospital have found. If retinal stem cells could be obtained, they might provide the basis for treatments to restore sight to millions of people with blindness caused by retinal degeneration. Stem cells are immature cells capable of producing large numbers of adult cells, such as retinal cells. Researchers believe that stem cells offer the promise of regenerating tissue in organs such as the eye, brain and heart, damaged by trauma or disease.

The new findings suggest that research on cell therapies to restore blindness should not concentrate on these eye cells previously believed to be retinal stem cells. More promising, the scientists said, is research aimed at re-engineering stem cells to develop into the light-sensitive photoreceptor cells that are lost as a result of retinal degeneration. Such studies could lead to implantation of such engineered photoreceptor cells into the eye to restore sight.

Led by Michael Dyer, Ph.D., the researchers published their findings March 30, 2009, in the online early edition of the Proceedings of the National Academy of Sciences. Dyer is a member of the St. Jude Department of Developmental Neurobiology.

In studies reported in 2000, scientists proposed that the layer of ciliary epithelial cells lining the inside of the eye, contains retinal stem cells because when grown in culture dishes these cells formed tiny spheres of about a thousand cells, said Dyer, the paper's senior author. These spheres, in turn, could be cultured to give rise to more spheres, reminiscent of the self-renewing capability of stem cells. Also, the cultured sphere cells showed activation of genes characteristic of adult eye cells.

"The first clue that these cells were not stem cells was that they were pigmented," Dyer said. "Neural stem cells, in general, and retinal progenitor cells, in particular, are not pigmented. Nevertheless, the previous finding was met with a tremendous amount of enthusiasm because of the promise of introducing these cells into the eye to regenerate photoreceptors lost to blindness."

In their studies, Dyer and his colleagues analyzed the sphere-forming cells in detail to determine whether they were really retinal stem cells. Painstaking microscopy studies of each cell in the spheres revealed all were pigmented and had features of ciliary epithelial cells. The researchers also compared the structure of the sphere-forming cells with those of confirmed stem cells and other immature cells in the developing retina called progenitor cells. That comparison revealed fundamental differences between the sphere-forming cells and established stem or progenitor cells.

The researchers also found that simply culturing the sphere-forming cells in the same growth medium as is used for stem cells caused them to activate genes characteristic of stem cells, yet remain adult ciliary epithelial cells.

Dyer said that a particularly promising alternative is the possibility of taking samples of adult cells - such as fibroblasts that form connective tissue - from a patient with retinal degeneration and exposing them to genetic cues that induce them to revert to stem cells. Those induced pluripotent stem cells could then be manipulated to develop into light-sensing photoreceptor cells that could then be transplanted into the patient's eyes to restore vision.

"This approach would solve many problems of developing cell-based therapy for blindness," Dyer said. "First, these cells are immortal, so they can be grown indefinitely to produce large amounts of cells for treatment. And secondly, they would be immunologically matched to the patient, so there would be no danger of rejection. And thanks to some excellent research during the past 15 years, we know a lot about how to reprogram such stem cells to make them into photoreceptors."

Other authors of this paper are Samantha Cicero, Sharon Frase, Samuel Connell, Lionel Chow, Suzanne Baker and Brian Sorrentino (St. Jude); Dianna Johnson (University of Tennessee Health Sciences Center); and Steve Reyntjens (FEI Helios Nanolab, Netherlands).

This research was supported in part by the National Institutes of Health, Cancer Center Support from the National Cancer Institute, American Cancer Society, Research to Prevent Blindness, Pearle Vision Foundation, International Retinal Research Foundation and ALSAC.

St. Jude Children's Research Hospital

St. Jude Children's Research Hospital is internationally recognized for its pioneering work in finding cures and saving children with cancer and other catastrophic diseases. Founded by late entertainer Danny Thomas and based in Memphis, Tenn., St. Jude freely shares its discoveries with scientific and medical communities around the world. No family ever pays for treatments not covered by insurance, and families without insurance are never asked to pay. St. Jude is financially supported by ALSAC, its fundraising organization. For more information, please visit www.stjude.org.


'/>"/>
SOURCE St. Jude Children's Research Hospital
Copyright©2009 PR Newswire.
All rights reserved

Related medicine news :

1. After heart attack, bone marrow stem cells increase blood flow within heart
2. Scientists Capture HIV Transfer Among T-Cells on Video
3. Study Links Sugar Production in Yeast Cells to Longevity
4. Physician Group Opposes FDA's Position on Adult Stem Cells
5. TV crime drama compound highlights immune cells misdeeds
6. Biotech company cofounded by BIDMC scientists targets natural killer T-cells
7. Master molecular switch may prevent the spread of cancer cells to distant sites in the body
8. Nanoscopic probes can track down and attack cancer cells
9. Dendritic cells ensure immune tolerance
10. Iron induces death in tumor cells
11. Seeing Stem Cells Helps in Fight Against Peripheral Arterial Disease
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/26/2016)... ... June 26, 2016 , ... Many women are ... with endometriosis. These women need a treatment plan to not only alleviate symptoms ... can help for preservation of fertility and ultimately achieving a pregnancy. The specialists ...
(Date:6/25/2016)... ... 2016 , ... First Choice Emergency Room , the largest network of ... Medical Director of its new Mesquite-Samuell Farm facility. , “We are pleased to ... said Dr. James M. Muzzarelli, Executive Medical Director of First Choice Emergency Room. ...
(Date:6/24/2016)... ... June 24, 2016 , ... A recent article published June 14 ... The article goes on to state that individuals are now more comfortable seeking to ... operations such as calf and cheek reduction. The Los Angeles area medical group, Beverly ...
(Date:6/24/2016)... ... 2016 , ... Global law firm Greenberg Traurig, P.A. announced that 20 Florida ... their peers for this recognition are considered among the top 2 percent of lawyers ... as members of this year’s Legal Elite Hall of Fame: Miami Shareholders Mark ...
(Date:6/24/2016)... Norcross, Georgia (PRWEB) , ... June 24, 2016 ... ... Year” awards today at the Clinical Decision Making in Emergency Medicine conference in ... who have authored journal articles published in Emergency Medicine Practice and ...
Breaking Medicine News(10 mins):
(Date:6/23/2016)... 2016 Roche (SIX: RO, ROG; OTCQX: RHHBY) ... Elecsys BRAHMS PCT (procalcitonin) assay as a dedicated testing ... With this clearance, Roche is the first IVD company ... for sepsis risk assessment and management. PCT ... PCT levels in blood can aid clinicians in assessing ...
(Date:6/23/2016)... 23, 2016 , , , ... 7, 2016 , , , , LOCATION: , , , ... , , , EXPERT PANELISTS:  , , , Frost & Sullivan,s ... Christi Bird; Senior Industry Analyst, Divyaa Ravishankar and Unmesh Lal, Program ... global pharmaceutical industry is witnessing an exceptional era. Several new demand ...
(Date:6/23/2016)... June 23, 2016 The vast majority of ... dialysis facility.  Treatments are usually 3 times a week, ... visit, including travel time, equipment preparation and wait time. ... especially grueling for patients who are elderly and frail.  ... nursing and rehabilitation centers for some duration of time. ...
Breaking Medicine Technology: