By Molika Ashford
In a stem-cell breakthrough, scientists have illuminated a new way forward in treating diseases of the eye: turning skin cells into eye cells.
The retina is a lush layered field of tissue lining the back of the eye, a complex mix of specialized cells that serve as a transfer station where light signals are absorbed and sent to the brain to be translated into sight.
Researchers from University of Wisconsin, Madison have now created these unique retina cells from lowly skin cells -- opening the possibility that patients with damaged or diseased retinas might some day be able to grow themselves a cure from their own skin.
First, scientists turned the skin cells into IPS cells (induced pluripotent stem cells), the skin-derived stem cells that have emerged as an alternative to embryonic stem cells. Bathed with a cocktail of chemicals, the IPS cells were then morphed into a variety of retinal cells, including the all-important photoreceptors that translate light signals into electrical signals for our brains to parse as vision.
The scientists report that it is exciting not only to be able to create multiple types of retinal cells, but also that the process appears quite similar to normal retinal development (except in a plastic dish). The group also created retinal cells with embryonic stem cells, but the skin cell method offers an advantage -- patients with genetic diseases of the retina could use their skin to grow a crop of diseased retina cells, which could then be subjected to a variety of test treatments in the lab, hopefully hitting on something that works someday.
The cells might also serve as a treatment themselves, whether grown from IPS cells or embryonic stem cells. Previous studies have improved vision in mice by treating their retinas with stem cells, and this development might help extend that research to humans.
Though in a very early stage, the project is a strong step toward new treatments for an array of debilitating vision disorders.
Friday, August 28, 2009
Tuesday, August 4, 2009
UF reports possible breakthrough on treating macular degeneration
By Diane Chun
Staff writer
Published: Saturday, August 1, 2009 at 5:30 p.m.
Last Modified: Saturday, August 1, 2009 at 5:30 p.m.
A new approach to repairing damaged retinas in mice offers a ray of hope for some two million Americans with an age-related eye condition called macular degeneration.
University of Florida researchers report that they were able to program adult stem cells from mice to transform themselves into vision cells, suggesting a potential treatment for one of the most common causes of vision loss in older people.
In a paper to be published in September's Molecular Therapy, scientists describe how they used a virus carrying a gene that gently pushed cultured adult stem cells toward a fate as retinal cells. When the cultured cells were reintroduced into the mice, they were completely transformed into the desired type of vision cells.
"To our knowledge, this is the first reported use of targeted gene manipulation to specifically program an adult stem cell to become a new cell type," said Dr. Maria Grant, professor of pharmacology and therapeutics in the UF College of Medicine.
Ultimately, Grant said, the findings suggest that the same thing could be done with drugs.
"You would not give the drugs to the patient," she explained, "you would give the drugs to their cells. Take the cells out, activate certain chemical pathways, then put the cells back into the patient."
The researchers were able to use chemical compounds that mirrored environmental conditions in the body to point the stem cells toward their ultimate identities as vision cells.
In essence, they were successful in tricking the stem cell into thinking it is a retinal cell and behaving accordingly.
"This implies a whole new field of stem cell research that uses drug manipulation rather than genetic manipulation to send these immature cells along a new pathway," said Grant.
She collaborated in the work with Edward Scott, director of the program in stem cell biology and regenerative medicine at UF's McKnight Brain Institute.
"This work applies to 85 percent of patients who have age-related macular degeneration," Grant said. "There are no therapies for this devastating disease."
for more information contact www.maculardegenerationassociation.org
Staff writer
Published: Saturday, August 1, 2009 at 5:30 p.m.
Last Modified: Saturday, August 1, 2009 at 5:30 p.m.
A new approach to repairing damaged retinas in mice offers a ray of hope for some two million Americans with an age-related eye condition called macular degeneration.
University of Florida researchers report that they were able to program adult stem cells from mice to transform themselves into vision cells, suggesting a potential treatment for one of the most common causes of vision loss in older people.
In a paper to be published in September's Molecular Therapy, scientists describe how they used a virus carrying a gene that gently pushed cultured adult stem cells toward a fate as retinal cells. When the cultured cells were reintroduced into the mice, they were completely transformed into the desired type of vision cells.
"To our knowledge, this is the first reported use of targeted gene manipulation to specifically program an adult stem cell to become a new cell type," said Dr. Maria Grant, professor of pharmacology and therapeutics in the UF College of Medicine.
Ultimately, Grant said, the findings suggest that the same thing could be done with drugs.
"You would not give the drugs to the patient," she explained, "you would give the drugs to their cells. Take the cells out, activate certain chemical pathways, then put the cells back into the patient."
The researchers were able to use chemical compounds that mirrored environmental conditions in the body to point the stem cells toward their ultimate identities as vision cells.
In essence, they were successful in tricking the stem cell into thinking it is a retinal cell and behaving accordingly.
"This implies a whole new field of stem cell research that uses drug manipulation rather than genetic manipulation to send these immature cells along a new pathway," said Grant.
She collaborated in the work with Edward Scott, director of the program in stem cell biology and regenerative medicine at UF's McKnight Brain Institute.
"This work applies to 85 percent of patients who have age-related macular degeneration," Grant said. "There are no therapies for this devastating disease."
for more information contact www.maculardegenerationassociation.org
Sunday, July 12, 2009
Study Published In PNAS Reveals Side Effects Of Experimental "Gene-Silencing" Treatment
The side effects of an experimental "gene-silencing" treatment that is currently being investigated for a variety of diseases are even more wide-ranging than previously discovered, according to a study by a University of Kentucky researcher.
Following up on groundbreaking research published last year in the journal Nature, Dr. Jayakrishna Ambati, a UK ophthalmologist , and his colleagues found that the new drug modality, siRNA (21-nucleotide small-interfering RNA), is toxic not only to blood endothelial cells, which line blood vessels, but also to the cells lining the lymphatic channels.
These findings reinforce the note of caution sounded by Ambati's previous Nature study, which has been cited nearly 50 times and highlighted in special reviews in premier journals such as Cell and in Nature, which termed it "stunning." But these side effects could themselves find useful application, for example, in cornea transplantation, where growth of new blood and lymph vessels is believed to be a major cause of graft failure.
The new findings are published in this week's online issue of Proceedings of the National Academy of Sciences, the official journal of the U.S. National Academy of Sciences.
In the earlier study, the Ambati laboratory discovered previously unrecognized immune side effects of siRNA, which is currently in FDA trials for numerous diseases including age-related macular degeneration and life-threatening viral infections.
Specifically, they showed that in two different established animal models of new blood vessel growth, siRNA killed these cells by activating an immune receptor called toll-like receptor 3 (TLR3). This was a critical finding, as immune and blood vessel toxicities were not believed to occur with this pharmacologic technique. As a result, siRNA is now recognized as a new class of anti-vascular drugs that could potentially be used to treat some of the 10 percent of the world's population suffering from neovascular diseases. However, this first study did not address other forms of specialized endothelial cells that exist in the human body, including those that line the lymphatic system, a critical component of immune responses. The new study found that siRNAs block not only blood vessels but also lymphatic vessels. In the cornea, the clear part of the eye, injury often leads to the formation of both blood and lymphatic vessels. In fact, the formation of lymphatic vessels after corneal transplantation is purported to be a major mechanism through which transplant rejection occurs. Ambati's lab found that corneal injections of siRNA suppressed both blood and lymphatic vessel growth via endothelial cell toxicity.
Won Gil Cho, post-doctoral fellow, Dr. Romulo Albuquerque, and Dr. Mark Kleinman, researchers in the Ambati laboratory, also showed that siRNA directly activates TLR3, the first time this has been demonstrated in the literature. Addditionally, they showed, using time-lapse studies, that siRNA does not enter cells without a cell-permeating moiety such as cholesterol. This is important, because siRNA must enter cells in order to function as intended by specifically degrading intracellular messenger RNA bound for protein-forming machinery. Furthermore, this finding strengthens their finding that TLR3 positioned on the cell surface is responsible for mediating the toxic side-effects of siRNA. In concert with Sandro De Falco and Arturo Brunetti, researchers in Naples, Italy, they also found that siRNAs generically block blood and lymphatic vessel growth in muscle tissue as well. These findings illustrate this side effect of siRNA can occur in many parts of the body.
Ambati's lab also reported last year in the New England Journal of Medicine that siRNA is deleterious to other cell types, such as the retinal pigmented epithelium, which is involved in age-related macular degeneration.
"This may be a broadly imprinted response in the mammalian immune system that is activated by siRNA," Ambati said. "In terms of benefit, siRNA may be utilized in the treatment of diseases of the lymphatic system, including lymphangiomas for which there is currently no effective targeted pharmacologic intervention."
Ambati is a Doris Duke Charitable Foundation Distinguished Clinical Scientist and a Burroughs Wellcome Fund Clinical Scientist in Translational Research. His laboratory is also supported by the National Eye Institute of the NIH, Research to Prevent Blindness, and American Health Assistance Foundation.
Following up on groundbreaking research published last year in the journal Nature, Dr. Jayakrishna Ambati, a UK ophthalmologist , and his colleagues found that the new drug modality, siRNA (21-nucleotide small-interfering RNA), is toxic not only to blood endothelial cells, which line blood vessels, but also to the cells lining the lymphatic channels.
These findings reinforce the note of caution sounded by Ambati's previous Nature study, which has been cited nearly 50 times and highlighted in special reviews in premier journals such as Cell and in Nature, which termed it "stunning." But these side effects could themselves find useful application, for example, in cornea transplantation, where growth of new blood and lymph vessels is believed to be a major cause of graft failure.
The new findings are published in this week's online issue of Proceedings of the National Academy of Sciences, the official journal of the U.S. National Academy of Sciences.
In the earlier study, the Ambati laboratory discovered previously unrecognized immune side effects of siRNA, which is currently in FDA trials for numerous diseases including age-related macular degeneration and life-threatening viral infections.
Specifically, they showed that in two different established animal models of new blood vessel growth, siRNA killed these cells by activating an immune receptor called toll-like receptor 3 (TLR3). This was a critical finding, as immune and blood vessel toxicities were not believed to occur with this pharmacologic technique. As a result, siRNA is now recognized as a new class of anti-vascular drugs that could potentially be used to treat some of the 10 percent of the world's population suffering from neovascular diseases. However, this first study did not address other forms of specialized endothelial cells that exist in the human body, including those that line the lymphatic system, a critical component of immune responses. The new study found that siRNAs block not only blood vessels but also lymphatic vessels. In the cornea, the clear part of the eye, injury often leads to the formation of both blood and lymphatic vessels. In fact, the formation of lymphatic vessels after corneal transplantation is purported to be a major mechanism through which transplant rejection occurs. Ambati's lab found that corneal injections of siRNA suppressed both blood and lymphatic vessel growth via endothelial cell toxicity.
Won Gil Cho, post-doctoral fellow, Dr. Romulo Albuquerque, and Dr. Mark Kleinman, researchers in the Ambati laboratory, also showed that siRNA directly activates TLR3, the first time this has been demonstrated in the literature. Addditionally, they showed, using time-lapse studies, that siRNA does not enter cells without a cell-permeating moiety such as cholesterol. This is important, because siRNA must enter cells in order to function as intended by specifically degrading intracellular messenger RNA bound for protein-forming machinery. Furthermore, this finding strengthens their finding that TLR3 positioned on the cell surface is responsible for mediating the toxic side-effects of siRNA. In concert with Sandro De Falco and Arturo Brunetti, researchers in Naples, Italy, they also found that siRNAs generically block blood and lymphatic vessel growth in muscle tissue as well. These findings illustrate this side effect of siRNA can occur in many parts of the body.
Ambati's lab also reported last year in the New England Journal of Medicine that siRNA is deleterious to other cell types, such as the retinal pigmented epithelium, which is involved in age-related macular degeneration.
"This may be a broadly imprinted response in the mammalian immune system that is activated by siRNA," Ambati said. "In terms of benefit, siRNA may be utilized in the treatment of diseases of the lymphatic system, including lymphangiomas for which there is currently no effective targeted pharmacologic intervention."
Ambati is a Doris Duke Charitable Foundation Distinguished Clinical Scientist and a Burroughs Wellcome Fund Clinical Scientist in Translational Research. His laboratory is also supported by the National Eye Institute of the NIH, Research to Prevent Blindness, and American Health Assistance Foundation.
Saturday, June 6, 2009
Exploiting Cortistatins' Essence
Simple analogs of a complex natural product may protect against loss of vision
Carmen Drahl
By making simplified versions of cortistatins, marine natural products that halt new blood vessel growth, researchers can treat excessive vessel growth in mice with macular degeneration. The analogs may inspire a new class of medications for the disease, which is a leading cause of vision loss.
Cortistatins A and J are potent blockers of angiogenesis, or new blood vessel growth, but the natural supply is scarce and chemical syntheses of the cortistatins haven't produced enough material for animal testing. Chemists Barbara Czakó, László Kürti, and E. J. Corey at Harvard University decided to study analogs instead.
"What distinguishes cortistatins are two basic groups at opposite ends of a steroidlike scaffold that are important for bioactivity," Corey says. His team incorporated those essential groups, a dimethylamino and an isoquinoline group, on opposite ends of an easy-to-build steroid and made refinements to optimize anti-angiogenic activity in cells. In collaboration with vascular biologists Akiko Mammoto and Donald E. Ingber of Harvard Medical School, they found that some of their compounds blocked angiogenesis in a mouse model of macular degeneration but did not show signs of toxicity in cellular assays (J. Am. Chem. Soc., DOI: 10.1021/ja902601e).
The most effective pharmaceutical treatment for macular degeneration is administered by injection into the eye, Corey notes. All of his team’s most potent analogs are water soluble and could lead to an eye-drop-based treatment, he says.
Chemist Samuel J. Danishefsky of Memorial Sloan-Kettering Cancer Center and Columbia University praised the work, saying that Corey's team “has increased the scope of the cortistatins by weaving them into a steroid setting which provided a doable terrain for chemical synthesis.”
"In terms of an exercise in blending intuition and rational discovery, this paper could emerge as a classic," Danishefsky adds.
Studies from other groups suggest that inhibitors of the particular angiogenesis pathway that the cortistatin analogs target may lead to side effects, cautions David A. Cheresh, who studies tumor angiogenesis at the University of California, San Diego. Nonetheless, the analogs "represent exciting new leads in the search for the next class of anti-angiogenic agents" and should be studied further, he adds.
Corey tells C&EN that the cortistatin analogs are effective in mice at very low doses of less than 1 mg and would also be locally administered. Therefore, the amount of drug that the rest of the body would see is likely to be essentially zero, vastly reducing the potential for side effects, he says.
In related work, independent teams led by Hiromasa Kiyota at Tohoku University in Japan and Phil S. Baran at Scripps Research Institute have tested simplified cortistatins in cells, but neither team has reported animal studies (Biosci. Biotechnol. Biochem. 2008, 72, 2992; Angew. Chem. Int. Ed., DOI: 10.1002/anie.200901116).
Carmen Drahl
By making simplified versions of cortistatins, marine natural products that halt new blood vessel growth, researchers can treat excessive vessel growth in mice with macular degeneration. The analogs may inspire a new class of medications for the disease, which is a leading cause of vision loss.
Cortistatins A and J are potent blockers of angiogenesis, or new blood vessel growth, but the natural supply is scarce and chemical syntheses of the cortistatins haven't produced enough material for animal testing. Chemists Barbara Czakó, László Kürti, and E. J. Corey at Harvard University decided to study analogs instead.
"What distinguishes cortistatins are two basic groups at opposite ends of a steroidlike scaffold that are important for bioactivity," Corey says. His team incorporated those essential groups, a dimethylamino and an isoquinoline group, on opposite ends of an easy-to-build steroid and made refinements to optimize anti-angiogenic activity in cells. In collaboration with vascular biologists Akiko Mammoto and Donald E. Ingber of Harvard Medical School, they found that some of their compounds blocked angiogenesis in a mouse model of macular degeneration but did not show signs of toxicity in cellular assays (J. Am. Chem. Soc., DOI: 10.1021/ja902601e).
The most effective pharmaceutical treatment for macular degeneration is administered by injection into the eye, Corey notes. All of his team’s most potent analogs are water soluble and could lead to an eye-drop-based treatment, he says.
Chemist Samuel J. Danishefsky of Memorial Sloan-Kettering Cancer Center and Columbia University praised the work, saying that Corey's team “has increased the scope of the cortistatins by weaving them into a steroid setting which provided a doable terrain for chemical synthesis.”
"In terms of an exercise in blending intuition and rational discovery, this paper could emerge as a classic," Danishefsky adds.
Studies from other groups suggest that inhibitors of the particular angiogenesis pathway that the cortistatin analogs target may lead to side effects, cautions David A. Cheresh, who studies tumor angiogenesis at the University of California, San Diego. Nonetheless, the analogs "represent exciting new leads in the search for the next class of anti-angiogenic agents" and should be studied further, he adds.
Corey tells C&EN that the cortistatin analogs are effective in mice at very low doses of less than 1 mg and would also be locally administered. Therefore, the amount of drug that the rest of the body would see is likely to be essentially zero, vastly reducing the potential for side effects, he says.
In related work, independent teams led by Hiromasa Kiyota at Tohoku University in Japan and Phil S. Baran at Scripps Research Institute have tested simplified cortistatins in cells, but neither team has reported animal studies (Biosci. Biotechnol. Biochem. 2008, 72, 2992; Angew. Chem. Int. Ed., DOI: 10.1002/anie.200901116).
Saturday, May 30, 2009
First Bionic Eye to Undergo Clinical Tests by 2011
The first clinical tests of a bionic eye are likely within two years and commercialization within five, according to researchers.
A bionic eye is a form of neural prosthesis intended to partially restore lost vision or amplify existing vision.
There is a lot of promising research being done right now. We are living in a very exciting time.
However, we can't put our plans and dreams on hold until this research delivers a cure.
I will never forget the day that I discovered a Telesensory video magnifier in a university library. It was 1977. I was just about to drop out of college before I made this discovery.
That video magnifier made it possible for me to complete college and live my dream as a public school teacher for 21 years!
Today I am very proud to own Amazing Video Magnifiers where I distribute only Telesensory video magnifiers.
They are, in my opinion, the most reliable and cost efficient.
I encourage you to visit the site and read about the various outstanding units.
A bionic eye is a form of neural prosthesis intended to partially restore lost vision or amplify existing vision.
There is a lot of promising research being done right now. We are living in a very exciting time.
However, we can't put our plans and dreams on hold until this research delivers a cure.
I will never forget the day that I discovered a Telesensory video magnifier in a university library. It was 1977. I was just about to drop out of college before I made this discovery.
That video magnifier made it possible for me to complete college and live my dream as a public school teacher for 21 years!
Today I am very proud to own Amazing Video Magnifiers where I distribute only Telesensory video magnifiers.
They are, in my opinion, the most reliable and cost efficient.
I encourage you to visit the site and read about the various outstanding units.
Sunday, May 10, 2009
New Medical Study Establishes First-Ever Long-Term Benefits for Macular Degeneration Sufferers Using Macular Health Vitamin Supplement
New Medical Study Establishes First-Ever Long-Term Benefits for Macular Degeneration Sufferers Using Macular Health Vitamin Supplement
Eye disease product has the potential to preserve vision for millions
BIRMINGHAM, Ala., April 28 /PRNewswire/ -- As many as 17.8 million people will suffer from age-related macular degeneration (AMD) by 2050 and 1.57 million will be blind from the disease, according to the U.S. Centers for Disease Control and Prevention. However, a new medical study by a group of retina specialists at the Callahan Eye Foundation Hospital at the University of Alabama Birmingham (UAB) indicates that with the use of the Macular Health vitamin supplement there is a way to reduce these numbers and potentially preserve the vision of millions.
The second phase of the Multifocal Electroretinogram (MERG) study recently revealed that patients suffering from AMD experienced long-term benefits from taking Macular Health, a special combination of supplemental vitamins, minerals and carotenoids. Phase I of the MERG study, completed in 2005, confirmed an average of 16 percent improvement in vision after taking Macular Health for only 12 weeks. Phase II measured the vision function of the same patients two years later and found an average improvement in vision of 17 percent.
"The outcome of this study is extremely encouraging for sufferers of age-related macular degeneration," says John O. Mason, III, MD, researcher and retinal specialist at the Callahan Eye Foundation Hospital. "These new findings prove that Macular Health can slow vision loss and actually improve vision function over time."
MERG testing was used to gauge the vision of AMD patients before and after using the Macular Health supplement. The test results of patients taking Macular Health were compared to results of a control group that did not take the supplement. Phase II of the study was accepted by the Association for Research and Vision in Ophthalmology (ARVO) for poster presentation. Mason and a team of retina specialists will continue to monitor study participants to evaluate improvement in eye health and vision with the use of Macular Health.
Jeffery McAnnally, President of Macular Health, LLC, says, "On behalf of the Macular Health Company, I am pleased to share this additional proof of Macular Health's effectiveness. Not only is Macular Health the most affordable product of its kind on the market today, it is the easiest to take."
An estimated 9 million people currently suffer from AMD, and one-third of adults over 70 are afflicted with this incurable disease. AMD is the leading cause of blindness in Americans 50 years of age and older. AMD is a breakdown of the macula of the eye that typically occurs during the aging process. Damage of the macula increases the difficulty of seeing fine details and even faces clearly.
To learn more about age-related macular degeneration or the Macular Health vitamin supplement, visit www.macularhealth.com. To speak with John O. Mason, III, MD, please contact Julie Ward at 205.503.5955 or julie@styleadvertising.com.
Website: http://www.macularhealth.com/
Eye disease product has the potential to preserve vision for millions
BIRMINGHAM, Ala., April 28 /PRNewswire/ -- As many as 17.8 million people will suffer from age-related macular degeneration (AMD) by 2050 and 1.57 million will be blind from the disease, according to the U.S. Centers for Disease Control and Prevention. However, a new medical study by a group of retina specialists at the Callahan Eye Foundation Hospital at the University of Alabama Birmingham (UAB) indicates that with the use of the Macular Health vitamin supplement there is a way to reduce these numbers and potentially preserve the vision of millions.
The second phase of the Multifocal Electroretinogram (MERG) study recently revealed that patients suffering from AMD experienced long-term benefits from taking Macular Health, a special combination of supplemental vitamins, minerals and carotenoids. Phase I of the MERG study, completed in 2005, confirmed an average of 16 percent improvement in vision after taking Macular Health for only 12 weeks. Phase II measured the vision function of the same patients two years later and found an average improvement in vision of 17 percent.
"The outcome of this study is extremely encouraging for sufferers of age-related macular degeneration," says John O. Mason, III, MD, researcher and retinal specialist at the Callahan Eye Foundation Hospital. "These new findings prove that Macular Health can slow vision loss and actually improve vision function over time."
MERG testing was used to gauge the vision of AMD patients before and after using the Macular Health supplement. The test results of patients taking Macular Health were compared to results of a control group that did not take the supplement. Phase II of the study was accepted by the Association for Research and Vision in Ophthalmology (ARVO) for poster presentation. Mason and a team of retina specialists will continue to monitor study participants to evaluate improvement in eye health and vision with the use of Macular Health.
Jeffery McAnnally, President of Macular Health, LLC, says, "On behalf of the Macular Health Company, I am pleased to share this additional proof of Macular Health's effectiveness. Not only is Macular Health the most affordable product of its kind on the market today, it is the easiest to take."
An estimated 9 million people currently suffer from AMD, and one-third of adults over 70 are afflicted with this incurable disease. AMD is the leading cause of blindness in Americans 50 years of age and older. AMD is a breakdown of the macula of the eye that typically occurs during the aging process. Damage of the macula increases the difficulty of seeing fine details and even faces clearly.
To learn more about age-related macular degeneration or the Macular Health vitamin supplement, visit www.macularhealth.com. To speak with John O. Mason, III, MD, please contact Julie Ward at 205.503.5955 or julie@styleadvertising.com.
Website: http://www.macularhealth.com/
Sunday, May 3, 2009
Possible Cure on Horizon
It's a sight for sore eyes.
Stem cell therapy to cure blindness is being developed by British scientists, and surgeons believe it could become a simple procedure that will be available in six or seven years' time, the London Times reported.
The process involves replacing a layer of dying cells with fresh ones created from embryonic stem cells.
It targets age-related macular degeneration (AMD), one of the most common causes of blindness, which involves the loss of eye cells.
"This is a huge step forward for patients," Tom Bremridge, chief executive of the Macular Disease Society, told the Times. "We are extremely pleased that the big guns have become involved, because, once this treatment is validated, it will be made available to a huge volume of patients."
Embryonic stem cells have the ability to develop into all types of body tissue.
Their use is controversial, however, because it involves the destruction of human embryos.
Lab tests done by the British team have shown that stem cells can prevent blindness in rats, and similar elements work on pigs.
A clinical trial is expected within two years.
It will most likely be the second in the world to use embryonic stem cells on humans. The first, spinal cord injury sufferers, will start later this year in the United States.
Stem cell therapy to cure blindness is being developed by British scientists, and surgeons believe it could become a simple procedure that will be available in six or seven years' time, the London Times reported.
The process involves replacing a layer of dying cells with fresh ones created from embryonic stem cells.
It targets age-related macular degeneration (AMD), one of the most common causes of blindness, which involves the loss of eye cells.
"This is a huge step forward for patients," Tom Bremridge, chief executive of the Macular Disease Society, told the Times. "We are extremely pleased that the big guns have become involved, because, once this treatment is validated, it will be made available to a huge volume of patients."
Embryonic stem cells have the ability to develop into all types of body tissue.
Their use is controversial, however, because it involves the destruction of human embryos.
Lab tests done by the British team have shown that stem cells can prevent blindness in rats, and similar elements work on pigs.
A clinical trial is expected within two years.
It will most likely be the second in the world to use embryonic stem cells on humans. The first, spinal cord injury sufferers, will start later this year in the United States.
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