Retina transplants show promise in patients with retinal degeneration

Jul 10, 2008

Preliminary research shows encouraging results with transplantation of retinal cells in patients with blindness caused by retinitis pigmentosa (RP) and age-related macular degeneration (AMD), according to a report in the August issue of American Journal of Ophthalmology.

In the FDA-monitored study, Dr. Norman D. Radtke of University of Louisville, Ky., lead author of the study and colleagues performed the experimental transplant procedure in ten patients with vision loss resulting from retinal degeneration: six patients with RP and four with the "dry" form of AMD. Although they have different causes, both RP and AMD lead to destruction of the light-receiving (photoreceptor) cells of the retina. There is currently no effective treatment for recovery of visual loss from either condition.

All patients underwent transplantation of fetal retinal cells. The cells were implanted along with their attached retinal pigment epithelium, which plays a key role in nourishing the photoreceptor cells. The concept behind the experimental procedure was that the new cells would grow to replace the damaged photoreceptor cells, connecting to the patient's remaining retina.

Follow-up testing showed visual improvements in seven of the ten patients: three of the patients with RP and all four patients with AMD. Although vision remained in the "legally blind" range for all patients, the gains in vision were significant and measurable.

"This clinical evidence shows the promise of our method to alter progressive vision loss due to incurable degenerative diseases of the retina," comments Dr. Radtke.

In one patient with RP, the visual improvement was still present up to six years after surgery, while vision in the opposite (untreated) eye continued to deteriorate. In the same patient, specialized tests showed a 27 percent increase in light sensitivity in the treated eye.

There were no problems with rejection of the transplants by the patients' immune systems, despite the lack of a perfect immunological match between the transplant donors and recipients. This likely reflected the special "immunologic protection" of tissues within the eye. Two patients also had improved vision in the untreated eyes. The reason for this unexpected result is unknown, but may involve some effect of transplantation on the immune system.

The experimental transplant procedure was designed on the basis of animal studies showing that transplantation of retinal cells can lead to the development of new retinal tissues. Previous "phase I" studies established the safety of the procedure. The new "phase II" trial provides the first evidence of improved vision—the first treatment of any type to restore lost vision in patients with RP or AMD.

Much further research will be needed to determine the potential for retinal transplantation to improve vision in patients with these diseases. "Retinal implants that combine retina and retinal pigment epithelium demonstrated an apparent ability to integrate with host retinas and to re-establish the visual pathways interrupted by disease," adds Dr. Radtke. "What we have learned will help us to refine this method and obtain further evidence that retinal implants may be a viable therapy for retinal degenerative disease."

Source: Elsevier

Explore further: Philippines boosts MERS monitoring after UAE nurse scare

add to favorites email to friend print save as pdf

Related Stories

New PRA gene identified in Phalenes and Papillons

Aug 29, 2013

Finnish researchers have identified a genetic mutation causing progressive retinal atrophy (PRA) in the Phalene and Papillon dog breeds. PRA is one of the most common causes of blindness in dogs and in human. ...

Japan OKs world's first iPS stemcell clinical trial

Jun 27, 2013

Japan has given the green light to the world's first clinical trial using stem cells harvested from a patient's own body, officials said Thursday, testing a treatment that may offer hope to millions of people robbed of their ...

Recommended for you

Two expats die of MERS in Saudi commercial hub

1 hour ago

Two foreigners died of MERS in the Saudi city of Jeddah, the health ministry said Saturday, as fears rise over the spreading respiratory virus in the kingdom's commercial hub.

UAE reports 12 new cases of MERS

1 hour ago

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.

Filipino tests negative for Middle East virus

13 hours ago

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

US orders farms to report pig virus infections

Apr 18, 2014

The U.S. government is starting a new program to help monitor and possibly control the spread of a virus that has killed millions of pigs since showing up in the country last year.

User comments : 0

More news stories

UAE reports 12 new cases of MERS

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...