Please note: This is an older post and there have significant challenges in stem cell research for eye disease since this was published. For more current information, see Our Readers Want to Know: What Is the Progress of Stem Cell Research for Eye Disease? Answer: It Has a Very Long Way to Go.
The London Project to Cure Blindness was established ten years ago in the United Kingdom with the goal of developing stem cell-based treatments to cure vision loss associated with age-related macular degeneration (AMD). The Project is the result of a partnership that includes Moorfields Eye Hospital, the University College London (UCL) Institute of Ophthalmology, and the Center for Stem Cell Biology at the University of Sheffield.
Since 2015, the Project has provided updates regarding their progress in stem cell treatments and retinal transplantation for both the wet and dry types of AMD. Most recently, as detailed below, the Project has released information about their progress in developing an affordable and effective stem cell replacement for retinal damage from dry AMD.
Please note: Although this stem cell research has produced interesting results, it is in its very earliest stages and must be subjected to additional, longer-term, rigorous study and clinical trials, encompassing many more years of research. Success in this area of research is not a foregone conclusion. At present, stem cell research is fraught with numerous stops and starts, high expectations, and frequent disappointments.
First, Some Basic Stem Cell Terminology
Here is a brief explanation of some key terms that are used in many types of stem cell research:
- Pluripotent: A stem cell that has the power to develop into any type of bodily cell or tissue (“pluri” = many; “potent” = having power)
- Induced pluripotent stem cells (iPSCs): A type of pluripotent stem cell that can be generated or “reprogrammed” directly from adult cells. Induced pluripotent stem cells require viruses to reprogram the cells, which has the potential to cause cancerous tumors.
- Embryonic stem cells (ESCs): Can form any cell type in the body. However, they are in limited supply, and – due to their origins – have ethical issues attached to their use.
- Human pluripotent stem cells (hPSCs): The term includes both human induced pluripotent stem cells (hiPSCs) and human embryonic stem cells (hESCs)
- Autologous: Involving one individual as both donor and recipient
- Retinal ganglion cells (RGCs): Neurons, or nervous system cells. They are located near the inner surface of the retina and give rise to optic nerve fibers that transmit information from the retina to several regions in the brain.
About the London Project to Cure Blindness
Excerpted from About Us at the London Project to Cure Blindness website:
The London Project to Cure Blindness has, for the past 10 years, been developing cell-based treatments to cure blindness associated with age-related macular degeneration (AMD). The group has been culturing embryonic stem cells, which give rise to all human cell types, to grow patches of retinal cells for transplant.
The project aims to bring stem cell therapy for retinal diseases, especially for AMD, to the clinic as rapidly as possible. We believe stem cell-based therapies for these conditions have the greatest chances of preventing blindness, restoring sight, and improving quality of life in the future.
The stem cell approach aims to replace cells in the eye that are either damaged or missing. In AMD the main cells that are initially affected are the retinal pigment epithelium cells (RPE). In the first of the trials developed by the London Project, we are using human embryonic stem cells (hES) that have been transformed into RPE cells. These RPE cells will then be transplanted under the patient’s retina on a specially engineered patch that the London Project has developed.
[Editor’s note: Retinal pigment epithelium (RPE) cells are the deepest cells of the retina. The RPE helps to maintain the health of the retinal photoreceptor cells, called rods and cones. These photoreceptor cells are triggered by light to set off a series of electrical and chemical reactions that helps brain to interpret what the eye sees. The degeneration of the RPE cells also leads to the death of the rods and cones and, ultimately, vision.]
More recently, The London Project has secured funding to examine the use of induced pluripotent stem cell (iPSC) (see explanation above) technology for transplantation. This allows the original cells to be taken from the person with the disease themselves and not from another source, such as an embryo.
Another important arm of the project is to develop the technology by which stem cells can be transformed into photoreceptors (primarily cones and rods) and transplanted into patients. It is believed that the photoreceptors are lost after the RPE cells have degenerated. [Editor’s note: You can read more about the function of retinal cones and rods at Some Facts about the Retina on the VisionAware website.]
2015: Initial Report: For Wet Macular Degeneration
A pioneering clinical trial of a new treatment derived from embryonic stem cells for people with wet age-related macular degeneration (AMD) has been initiated at Moorfields Eye Hospital in London, following a successful operation on a 60-year-old woman. She is the first of 10 persons with wet AMD who will receive the stem cell treatment as part of an 18-month clinical trial to test the safety and effectiveness of this procedure.
This initial operation is a key component of the London Project to Cure Blindness. You can read more at First patient receives potential new treatment for wet age-related macular degeneration in London Project to Cure Blindness.
2016: Second Report: For Dry Macular Degeneration
Edited and excerpted from Dry AMD Treatment’s “Major Achievement”, via the United Kingdom-based Optometry Today:
The [Project’s] first-ever treatment for dry age-related macular degeneration (AMD) has been a success, attendees of the Moorfields Eye Hospital annual general meeting heard on July 20, 2016 in London, England. Professor Pete Coffey, director of The London Project, emphasized that his team had developed an [experimental] stem cell replacement for retinal damage from dry AMD [that was implanted into two initial patients].
In the project’s first stage, researchers used human embryonic stem cells to regrow retinal pigment epithelium cells on an artificial membrane, creating a specialized patch. This patch was then surgically inserted, in a 45-minute Moorfields operation, into the middle of the retina in the trial patients.
The official research results for the first two patients to receive the patch will be released shortly, but in the meantime, the research will enter the second phase. Instead of receiving an artificial membrane with just retinal pigment epithelial cells on, the next cohort of patients would receive a patch with all three layers of the retina, Professor Coffey said. “Blood cells, vascular cells, neural cells, support cells – it will rebuild the whole macula,” he added.
And this would be developed from the patient’s own cells, he explained, adding: “Using four genetic switches on a piece of skin, we can get the beginning cell that made you.” The use of the patient’s cells meant that their DNA could also be studied at the same time, potentially allowing for a personalized diagnosis of their condition, as well as an individualized treatment, Professor Coffey told the audience.
More Information about Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a gradual, progressive, painless deterioration of the macula, the small sensitive area in the center of the retina that provides clear central vision. Damage to the macula impairs the central (or “detail”) vision that helps with essential everyday activities, such as reading and writing, preparing meals, watching television, and personal self-care.
AMD is the leading cause of vision loss for people aged 60 and older in the United States. According to the American Academy of Ophthalmology, 10-15 million individuals have AMD and about 10% of people who are affected have the “wet” type of AMD.
Wet (Neovascular) Macular Degeneration
In wet, or exudative, macular degeneration (AMD), the choroid (a part of the eye containing blood vessels that nourish the retina) begins to sprout abnormal new blood vessels that develop into a cluster under the macula, called choroidal neovascularization (neo = new; vascular = blood vessels).
Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid under the macula, causing it to lift up and pull away from its base. This damages the fragile photoreceptor cells, which sense and receive light, resulting in a rapid and severe loss of central vision.
Dry Macular Degeneration
The dry (also called atrophic) type of AMD affects approximately 80-90% of individuals with AMD. Its cause is unknown, it tends to progress more slowly than the wet type, and there is not – as of yet – an approved treatment or cure. “Atrophy” refers to the degeneration of cells in a portion of the body; in this case, the cell degeneration occurs in the retina.
In dry age-related macular degeneration, small white or yellowish deposits, called drusen, form on the retina, in the macula, causing it to deteriorate or degenerate over time.
A retina with drusen
Drusen are the hallmark of dry AMD. These small yellow deposits beneath the retina are a buildup of waste materials, composed of cholesterol, protein, and fats. Typically, when drusen first form, they do not cause vision loss. However, they are a risk factor for progressing to vision loss.
Risk Factors for Macular Degeneration
The primary risk factors for AMD include the following:
- Smoking: Current smokers have a 2-3 times higher risk for developing AMD than do people who never smoked. It’s best to avoid second-hand smoke as well.
- Sunlight: Ultraviolet (UV) light is not visible to the human eye, but can damage the lens and retina. Blue light waves that make the sky, or any object, appear blue, are visible to the human eye and can also damage the lens and retina. Avoid UV light and blue/violet light as much as possible by wearing sunglasses with an amber, brown, or orange tint that blocks both blue and UV light.
- Uncontrolled hypertension: The National Eye Institute (NEI) reports that persons with hypertension were 1.5 times more likely to develop wet macular degeneration than persons without hypertension. It’s important to keep your blood pressure controlled within normal limits.
- A diet high in packaged, processed food and low in fresh vegetables: NEI suggests that eating antioxidant-rich foods, such as fresh fruits and dark green leafy vegetables (kale, collard greens, and spinach) may delay the onset or reduce the severity of AMD. Eating at least one serving of fatty fish (salmon, tuna, or trout) per week may also delay the onset or reduce the severity of AMD.
- Race: According to NEI, Whites/Caucasians are more likely to have AMD than people of African descent.
- Family history: NEI reports that individuals with a parent or sibling with AMD have a 3-4 times higher risk of developing AMD.
You can read more about the full range of AMD risk factors at Risk Factors for Age-Related Macular Degeneration on the VisionAware website.
Additional Information
- VisionAware will continue to provide updates on this research as they become available.
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