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Spring 2006 Table of Contents
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Research:  Looking for Treatments and Cures in Blindness

By Kate Moss, Deafblind Education Specialist, Texas Deafbind Outreach, TSBVI

Abstract:  There is some fascinating research underway in the area of blindness.  The Foundation Fighting Blindness is a major contributor to this effort and has much to share on their website for those who want to keep up with this research.

Key words:  Programming, blindness, visual impairment, deafblindness, Retinitis Pigmentosa, Usher syndrome, macular degeneration, Stargartz

One of the greatest dreams for many people with blindness and their families may be that someday there will be a cure or treatment for blindness that can restore vision to those who have lost it and/or delay any potential loss of vision.  We are living in a remarkable age, and it is very likely that in the lifetime of many of our readers such a dream may become reality for many people, especially those whose vision loss is caused by certain diseases or syndromes.  Most research efforts are still in the early stages using animal models; a few are beginning very limited human trials.  Undoubtedly some will prove successful and some will not, but it is exciting to learn more about what is being done.  This work falls generally into four categories: 

The Foundation Fighting Blindness (FFB) is funding much of the work.  The FFB has as its mission to drive the research that will provide preventions, treatments and cures for people affected by retinitis pigmentosa (RP), macular degeneration, Usher Syndrome, and the entire spectrum of retinal degenerative diseases. The Foundation has funded thousands of research studies at hundreds of prominent institutions in promising areas such as genetics, gene therapy, retinal cell transplantation, artificial retinal implants, and pharmaceutical and nutritional therapies. Since its inception in 1971, the Foundation has raised over $240 million and provided information for patients, families and professionals.  It has over 30 volunteer-led groups across the US. These dedicated volunteers raise funds, increase public awareness, and provide support in their communities. For more information about FFB contact them at:

11435 Cronhill Drive
Owings Mills, MD 21117-2220
800-683-5555 800-683-5551 TDD
www.FightBlindness.org

If you visit the FFB website you can find out more about specific research that is being done, and keep up on new research findings.

Genetics and Gene Therapy

Genetics

Many of the research efforts focus on identifying specific genes that may cause retinal problems resulting in visual impairments and blindness.  Some of the syndromes that are being studied include

Usher syndrome, Stargartz, Leber’s Congenital Amaurosis, Age-Related Macular Degeneration – wet type, Chorioideremia and Retinoschisis.  Much of the work that is going on around the world involves learning what genes cause what conditions and diseases.  The Human Genome Project is a 13-year project completed in 2003 involving scientists from the United States, the United Kingdom, Japan, France, Germany, China, and other countries.  This truly amazing work will undoubtedly lead to vastly improved knowledge of, and ability to treat, diseases and conditions that affect the human body in all areas including vision and hearing loss.  The project mission has been to:

 (Human Genome Project - <www.ornl.gov/sci/techresources/Human_Genome/home.shtml>, 2006)

Genetics sets the stage for the work that is done in gene therapy.  Specific research into genes that cause visual problems has been done by a number of different programs.  One that has been very active in addressing Usher Syndrome and other hereditary causes of deafness is the Boys Town Research Hospital.  Many families from Texas have participated in this research, giving DNA samples from each member of the family.  To learn more about these research efforts in the area of Usher Syndrome, go to <www.boystownhospital.org/Usher/index.asp>.

Gene Therapy

Gene therapy involves the insertion of genes into an individual’s cells and tissues to treat diseases, particularly hereditary diseases. This therapy sets out to transform either somatic cells (most cells in the body) or germline cells (such as sperm, ova, and stem cell precursors).  So far, gene therapy is primarily directed at somatic cells.

Somatic gene therapy falls into two broad categories:  ex vivo (cells are modified outside the body and transplanted back in) and in vivo (genes are changed in cells while still in the body).  Some of these gene therapies use viruses that, in simple terms, have had the diseased part of the gene strand taken out and replaced with material from the “good gene”.  This is an huge oversimplification of course, but basically the virus inserts itself into the cell and gives new instructions from the “good gene” for what the cell is supposed to do.  (Wikipedia - <http://en.wikipedia.org/wiki/Gene_therapy> , February 2006)

In another FFB-funded research program, Copernicus Therapeutics is using nanoparticles as a way to deliver genetic material to the retina.  They have completed a trial on humans using this technology related to addressing cystic fibrosis.  (Foundation Fighting Blindness - <http://www.blindness.org/content.asp?id=251>, 2006.)  Nanoparticles are microscopic particles whose size is measured in nanometres, with at least one dimension <100nm. Nanoparticles are made of semiconducting material. (Wikipedia - <http://en.wikipedia.org/wiki/Nanoparticle>, 2006)

One of the newest research breakthroughs related to gene therapy applies to Leber’s Congenital Amaurosis (LCA).  Scientists have successfully used a RPE65 gene replacement therapy to restore vision in dogs born blind as a result of LCA.  Researchers hope to get permission to begin clinical trials on humans in 2006. To learn more about this program and various other research projects supported by FFB, go to <www.blindness.org/content.asp?id=251>.

Retinal Implants and Transplants

Implants

In the 1980s, the Massachusetts Eye and Ear Infirmary-Harvard Medical School began collaborating with the Massachusetts Institute of Technology to develop a microelectronic retinal implant for restoring vision to patients with age-related macular degeneration or retinitis pigmentosa.  (Boston Retinal Implant Project - <http://www.bostonretinalimplant.org>, 2006)  This project has been funded by the National Science Foundation, the W.M. Keck Foundation, the National Institutes of Health and Second Sight Corporation, the Foundation Fighting Blindness, the VA Rehabilitation Research & Development Service, the Wynn Foundation, and the Lions Club of Massachusetts.

A retinal implant is something similar to a cochlear implant used to help people with hearing loss.  The Boston Project describes what its implant does this way.

Patients with macular degeneration and retinitis pigmentosa become blind when the photoreceptors (light capturing cells in the eye) no longer function. The retinal prosthesis is designed to take over the function of the lost photoreceptors by electrically stimulating the remaining healthy cells of the retina. Through electrical stimulation, the activated ganglion cells can provide a visual signal to the brain. The visual scene captured by a camera is transmitted via electromagnetic radiation to a small decoder chip located on the retinal surface. Data and power are then sent to a set of electrodes connected to the decoder. Electrical current passing from individual electrodes stimulate cells in the appropriate areas of the retina corresponding to the features in the visual scene. (Boston Retinal Implant Project - <http://www.bostonretinalimplant.org/project/prosthesis.xml> , 2006.)

Another group, Optobionics and the University of Southern California, are also working on retinal implants.  In fact, they have actually implanted some humans.  Most experienced at least a temporary improvement in their vision, such as perceiving increased light, detecting motion and shapes, and in some cases even reading large letters. (Foundation Fighting Blindness - <http://www.blindness.org/content.asp?id=209>, 2006)

It is important to mention that a retinal implant does not restore vision to normal, just as a cochlear implant does not restore hearing to normal.  What it can do is give the person more visual ability for increased mobility, confidence, and safety when traveling through the environment. 

There are challenges in designing retinal implants that will work well.  Issues such as providing the right amount of electrical energy to stimulate the rods and cones without damaging them, how to mount the camera, how to power the processor, and so forth have yet to be satisfactorily addressed.  However, great strides are being made every day in this area, and though it sounds like something from a science fiction movie, effective implants may not be that far away.

Transplants

Although significant research has been undertaken related to transplants in the retina of the eyeball, there have been very limited successes.  Three types of transplants are commonly the focus of these efforts: 

All three of these transplants hold promise, but results still seem a long way off.  Probably the most exciting is the prospect of using stem cells to rebuild a retina—another piece of science fiction that may come to pass in the future.

Pharmaceutical Therapies

Cells are programmed to die when they are diseased or unwanted.  This is known as Programmed Cell Death (PCD), and the process by which it takes place is called apoptosis.  Too much apoptosis causes cell-loss disorders (like Retinitis Pigmentosa), and too little apoptosis causes cancerous tumors.  Much of the pharmaceutical therapy research is aimed at slowing down the process of programmed cell death in the photoreceptors of the eye through a neurotropic agent.  Neurotropic agents may or may not be produced naturally by the body.  At this point, getting these agents into the retina would involve frequent injections into the retina, which is not a good idea.  One approach to address this problem is the development of intraocular slow-release capsules, inserts, and trans-scleral delivery systems. (Progress in the Treatment of Deaf-Blind – PowerPoint presentation by Dr. Geral J. Chader, 2005.)

Nutritional Therapies

Work is also being done to determine if diet can play a part in preventing or slowing the progress of vision loss.  For example, one study through FFB is looking at the benefits of dietary supplementation with vitamin A palmitate, in combination with the omega-3 fatty acid DHA (docosahexanoic acid), to slow loss of vision in people with retinitis pigmentosa (RP).

“The combined therapy was found to primarily benefit people not previously taking vitamin A. For those people already taking vitamin A, a diet rich in omega-3 fatty acids is indicated to slow the decline in visual field sensitivity. Good sources of omega-3 fatty acids include: salmon, tuna, mackerel, sardines, and herring. For more information on dietary supplementation for RP, see the following link:< http://www.blindness.org/rp-nutrition/index.asp>.” (Foundation Fighting Blindness - <http://www.blindness.org/content.asp?id=251>, 2006.)

In another study, research seems to indicate that diets high in fats like those found in processed baked goods increase the risk of age-related macular degeneration.  Diets that are high in omega-3 fatty acids, like those found in nuts and fish, appear to delay the progression of the disease. (Foundation Fighting Blindness - <http://www.blindness.org/content.asp?id=251>, 2006)

It only makes sense that what we put into our bodies can impact how well our bodies function.  Still, there is much to be learned.  Before considering changes in diet, especially when adding vitamins orsupplements, it is important to discuss these changes with a doctor.  Vitamins and other nutritional substances can do more harm than good if not taken in the proper balance.  There may also be precautions against taking supplements if, for example, you are pregnant.  So if you are interested in exploring one of these nutritional programs, visit with your doctor first to learn more about the possible benefits and risks.

Conclusion

Some researchers and others speak of a day, one too far away at the moment to seem real, when we might be able to correct genetically caused visual problems before a child is born.  Only time and research will tell if this is possible.  But so much is now being learned about genetics, gene structure, and genetic engineering that some of us may live to see such a day.  Even if that day never comes, perhaps some of the advances in biotechnology will bring about retinal implants or transplants that can restore sight.  It would be a wonderful day!  Until then, we must put our efforts into supporting research and also into helping individuals with blindness and visual impairments get the skills and opportunities in they need to have successful and satisfying lives.

References and Resources

Boston Retinal Implant Project - <http://www.bostonretinalimplant.org/project.xml>

Boys Town Research Hospital - <http://www.boystownhospital.org/home.asp>

Chader, Gerald J. 2005.  Progress in the Treatment of Deaf-Blind – PowerPoint presentation by Dr. Gerald J. Chader, Doheny Retina Institute, Keck medical School, University of Southern California, Los Angeles, CA for the 2005 Deaf-Blind Project Director’s Meeting.

Foundation Fighting Blindness – <www.blindness.org>

Human Genome Project - <www.ornl.gov/sci/techresources/Human_Genome/home.shtml>

Wikipedia - http://en.wikipedia.org/wiki/Main_Page


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