Univ of Iowa Research Team Finds New Genetic Cause of Retinitis Pigmentosa

Combining the expertise of several different labs, University of Iowa researchers have found a new genetic cause of the blinding eye disease retinitis pigmentosa (RP) and, in the process, discovered an entirely new version of the message that codes for the affected protein.

The study, which was published online August 8 in the Proceedings of the National Academy of Sciences (PNAS) Early Edition, suggests that the mutation may be a significant cause of RP in people of Jewish descent. The findings also lay the groundwork for developing prevention and treatment for this form of RP using a combination of genetic testing, gene therapy and cell replacement approaches.

Using the latest DNA sequencing techniques to analyze the protein-coding regions of a single RP patient’s genome, the researchers found a mutation in a gene called MAK (male germ cell associated kinase). This gene had not previously been associated with eye disease in humans. However, examining tissue from donated eyes showed that MAK protein was located in the parts of the retina that are affected by the disease.

The researchers then generated induced pluripotent stem cells (iPSCs) from the patient’s own skin cells and coaxed these immature cells to develop into retinal tissue. Analyzing this tissue showed that the gene mutation caused the loss of the MAK protein in the retina.

“These new technologies have greatly enhanced our ability to find and validate disease-causing mutations, which is critical to our ability to progress to the next step of actually treating diseases like RP,” said Budd Tucker, PhD, UI assistant professor of ophthalmology and visual science and lead study author.

Based on the new work, the UI team hopes to explore gene therapy and cell replacement strategies as potential therapies for this form of RP.

http://www.uihealthcare.org/Newsarticle.aspx?id=225780

 

New Subretinal Stem Cell Treatment for Eye Disease

Ridgefield, CT (PRWEB) September 1, 2010
A new stem cell therapy is now available to eye patients using subretinal placement of adult stem cells. Patients with more severe eye problems may now have the opportunity to improve their sight and gain useful vision.

Dr Steven Levy is pleased to announce that The XCell-Center in Germany has begun a new treatment for eye patients using subretinal placement of adult stem cells for ophthalmic disease. Initial patients included an individual with Stargardts Disease, a type of hereditary retinopathy, and a patient with Age Related Macular Degeneration or AMD.

http://www.prweb.com/releases/2010/09/prweb4427444.htm

Researchers create retina from embryonic cells

Researchers in the US have successfully created a retina from human embryonic stem cells, which offers hope to millions with degenerative eye disorders.

Experts at the University of California Irvine created an eight-layer, early stage retina from human embryonic stem cells, which is the first ever three-dimensional tissue structure to be made from stem cells.

Study leader Hans Keirstead of the Reeve-Irvine Research Center and the Sue and Bill Gross Stem Cell Research Center at the facility, said the process also marks the first step towards the development of transplant-ready retinas to treat conditions such as retinitis pigmentosa and macular degeneration, a leading cause of blindness.

New Drugs Being Developed for Macular Degeneration

In 2005, two genetic studies of people with age-related macular degeneration (AMD)–the most common cause of blindness in people older than 65–made a surprising discovery. Research showed that defects in a gene that is an important regulator of parts of the immune system significantly increased risk of the disease. Scientists have since identified variants in several related genes that also boost risk, and which collectively account for about 50 to 60 percent of the heritability of the disorder.

Eye colors: Drusen, the yellow flecks in this image of the retina, are common in people with age-related macular degeneration. These flecks are made up of proteins involved in the part of the immune system called the complement system, which has also been implicated in the disease by genetic studies. Credit: National Eye Institute

At the same time that researchers identified the harmful variation linked to AMD, Gregory Hageman, now at the University of Utah, identified a protective variant found in about 20 percent of the population. “That form is so incredibly protective that people with two copies are almost guaranteed not to develop the disease,” he says. Hageman founded Optherion, a startup based in New Haven, CT, and investigated how to translate the findings into new treatments. Optherion is now producing large quantities of an engineered version of the protein and doing preclinical safety and effectiveness testing–for example, examining whether the treatment can reduce ocular deposits in mice that lack the protein, says Colin Foster, Optherion’s president. He declined to estimate when the company will begin clinical trials of the drug.

http://www.technologyreview.com/biomedicine/25386/?ref=rss&a=f

Gene discovery may help hunt for blindness cure

LONDON (Reuters) – Scientists have discovered a gene mutation linked to the most common cause of blindness in the developed world, holding out the prospect of better treatments and perhaps eventually a cure.

British scientists said on Tuesday they had found six variants within the gene called Serping1 that were associated with age-related macular degeneration (AMD).

“Our findings add to the growing understanding of the genetics of age-related macular degeneration, which should ultimately lead to novel treatments for this common and devastating disease,” Sarah Ennis and Andrew Lotery of the University of Southampton reported in the Lancet journal.

http://www.calgaryherald.com/health/Gene+discovery+help+hunt+blindness+cure/868657/story.html#ixzz0n99w6KAq

Frontiers of Medicine – Restoring Sight

RESTORING SIGHT

Challenge: A genetic disease degrades sight in children and blinds them by adulthood.
Radical Cure: Replace the defective genes with healthy ones.
Status: Three to five years to FDA approval

Popular Science article

Jean Bennett, a molecular geneticist at the University of Pennsylvania School of Medicine, has treated a dozen legally blind patients with Leber’s congenital amaurosis, a single-gene defect that prevents the retina from producing the proteins that play a vital role in maintaining the health of the eyes’ light receptors. For most sufferers, vision begins failing in early childhood. Without the treatment, there is no question that they, or any other sufferer of LCA, will eventually go totally blind.

With additional studies, Bennett says that she could have a drug ready in three years that any retinal surgeon could administer to cure LCA. But she’s not stopping there. Only five children born in the U.S. annually have the same type of LCA as Morehouse, but focusing on a rare single-gene defect is a good way to develop a model for treating more common ailments. “Our success shows that this technique is possible,” Bennett says. “We think this could be a platform for a lot of different blinding diseases.” Within the decade, she says, therapies involving similar eye genes could improve sight in people with other mutations, such as retinitis pigmentosa or macular degeneration.

How It Works

A virus carrying copies of the healthy gene is injected near the eye’s retinal-pigment epithelium cells. The virus invades the cells, which convert the new genes into the proteins that supply the rods and cones with the vitamin A necessary to form the pigment that absorbs light and allows a person to see.

http://www.popsci.com/science/article/2010-02/radical-cures?cmpid=enews030410

Some insurance companies now covering genetic test for macular degeneration

The test, Macula Risk, can tell if someone with a mild form of Macular Degeneration is likely to progress to a severe stage with vision loss, Eaton said.

More than 7 million Americans have intermediate age-related macular degeneration with symptoms of blurry vision, difficulty telling colors apart, distorted vision and shadows. The “wet” form of the disease involves abnormal blood vessel growth behind the eye, which leads to fluid leakage. Straight-ahead vision can become distorted or lost entirely in a short period of time.

Available from Canadian-based ArcticDX, the genetic test came on the market last year but insurance companies at the time were not covering the $400 expense. Now insurers are covering the cost if someone already has been diagnosed with early stage disease.

Gregory Hines, president and chief executive officer of ArcticDX, based in Toronto,  said a handful of insurers, namely Medicare, Blue Cross/Blue Shield and Cigna, were the first to cover the test and the other major insurers are starting to follow suit when there already has been a diagnosis of the disease.

In the event an insurance company denies coverage for a patient who meets criteria for the test, Arctic DX will bear the cost, Hines said.

For more information, visit the website ArcticDX. com

http://www.naplesnews.com/news/2010/feb/24/genetic-test-macular-degeneration-Macula-Risk/

Researchers Develop New Tool for Gene Delivery to Retina

 Researchers at Tufts University School of Medicine and the Sackler School of Graduate Biomedical Sciences at Tufts have developed a new tool for gene therapy that significantly increases gene delivery to cells in the retina compared to other carriers and DNA alone, according to a study published in the January issue of The Journal of Gene Medicine. The tool, a peptide called PEG-POD, provides a vehicle for therapeutic genes and may help researchers develop therapies for degenerative eye disorders such as retinitis pigmentosa and age-related macular degeneration.

“For the first time, we have demonstrated an efficient way to transfer DNA into cells without using a virus, currently the most common means of DNA delivery. Many non-viral vectors for gene therapy have been developed but few, if any, work in post-mitotic tissues such as the retina and brain. Identifying effective carriers like PEG-POD brings us closer to gene therapy to protect the retinal cells from degeneration,” said senior author Rajendra Kumar-Singh.

http://www.newswise.com/articles/view/560716/?sc=rssn

Predictive Tests for Age-related Macular Degeneration (AMD)

Methods for identifying a subject at increased risk for developing AMD by determining the presence of protective genotypes at either the BF/C2 locus and at the CFH locus.

The NCI Laboratory of Genomic Diversity is seeking statements of capability or interest from parties interested in collaborative research to further develop, evaluate, or commercialize functional or genetic tests on complement genes and proteins. Please contact Kathleen Higinbotham at 301-846-5465 for more information.

http://pharmalicensing.com/public/outlicensing/view/4468

Gene Therapy Creates a New Fovea

Twelve months after receiving an experimental gene therapy for a rare, inherited form of blindness, a patient discovered that she could read an illuminated clock in the family car for the first time in her life. The unexpected findings suggest that the brain can adapt to new sensory capacity, even in people who have been blind since birth.

The patient, who remains anonymous, suffers from a disease called Leber congenital amaurosis, in which an abnormal protein in sufferers’ photoreceptors severely impairs their sensitivity to light. “It’s like wearing several pairs of sunglasses in a dark room,” says Artur Cideciyan, a researcher at the University of Pennsylvania in Philadelphia, who oversaw the trial.

At the start of the study, physicians injected a gene encoding a functional copy of the protein into a small part of one eye–about eight-to-nine millimeters in diameter–of three patients, all in their twenties and blind since birth. In preliminary results published last year, Cideciyan and colleagues found that all three patients showed substantial improvements in their ability to detect light three months after treatment.

http://www.technologyreview.com/biomedicine/23239/