Ethics Pros and Cons – Therapy, Debate, and Controversy
A revolutionary technique being developed by British scientists could cure blindness in millions of people around the world. The first 45-minute operations could take place within five years and could be as commonplace as cataract surgery in a decade.The improvement is likely to be great enough to transform lives, allowing the blind to regain the ability to carry out everyday tasks such as reading or driving.
The pioneering Stem cell surgery tackles age-related macular degeneration (AMD), the most common cause of blindness in the elderly. There are about 300,000 sufferers in this country and the number is expected to treble in the next 25 years to around one million as the population ages.
Sight degenerates as cells die. AMD, which affects a quarter of over-60s in the UK and more than half of over-75s to some degree, occurs in two forms. While the “wet” form can be combated with drugs, there is no treatment for the “dry” form which accounts for 90 per cent of cases.
The treatment centers on human embryonic Stem Cells grown in a laboratory. These are “blank” cells with the power to turn into different cell types and are used to create small patches identical to the cells damaged in the eyes of AMD sufferers.
Packaged into a syringe, the patch is injected into the back of the eye where it replaces damaged cells and restores sight.
The technique is being developed by scientists and doctors from University College London, Moorfields Eye Hospital, also in London, and Sheffield University, working together in the London Project to Cure Blindness.
Their work has been boosted by a £4million donation from an anonymous American benefactor. Last night project director Professor Pete Coffey said: “This could have a tremendous effect on a huge population who have no current therapy.”
How the new treatment will help save a patient’s eyesight
The technique has been tested on rats suffering from a condition similar to AMD and their sight was restored.
Further evidence that the technique is likely to succeed comes from human operations. In these, the researchers restored vision using healthy cells taken from the corner of the patient’s own eye.
In some cases, the transplants were so successful that the patients were able to read, cycle and use a computer.
However, such surgery is extremely complex and time-consuming and so unlikely to be suitable for large-scale use. Using “readymade” patches of cells would greatly simplify the operation, making it suitable for use on millions.
The scientists are now working on making such patches, measuring just four by six millimeters, which will be injected into the back of the eye under local anesthetic in an procedure lasting between 45 minutes and an hour.
The patient, who would have to take drugs to stop the cells from being rejected by the body, could go home the same day. After two to three weeks, vision should start to improve.
It is not yet known how long the effects will last but the patients who had transplants of their own cells are still benefiting from the treatment which took place two and a half years ago.
While the patches are most likely to benefit those in the early stages of AMD, the researchers believe it should be possible to adapt them to treat those in later stages.
It is hoped that the technique might also benefit those who have lost their sight as a complication of diabetes.
Consultant surgeon Lyndon da Cruz of Moorfields Eye Hospital said that within ten years the procedure could become as commonplace as cataract surgery.
He said: “If we can do a single procedure in a person under local anesthetic in 45 minutes, it’s feasible.
“The science is something we can work on but the surgery has to be something we can deliver to many people.”
Eye experts said the research offered real hope to sufferers of AMD. Tom Bremridge of the Macular Disease Society said: “This development is exciting and encouraging for current and future generations of AMD patients.
“While treatments for “wet” AMD are advancing rapidly, sadly, patients with “dry” AMD have had no prospect of any viable therapy.”
Professor Alistair Fielder, of the charity Fight for Sight, said the research represented “a real chance to tackle an untreatable condition and bring hope to many”.
He added: “It is marvellous to think that clinical trials could start within four years.”
Although many believe it is wrong to use embryonic stem cells – plucked from an embryo in the first days of life – in medicine, sophisticated laboratory techniques mean it should be possible to generate a treatment for millions of people from cells derived from a single embryo.
Stem cell research offers hope for treating and curing a host of conditions.
In recent work, British experts have succeeded in growing a “miniliver” – a tiny bundle of liver cells – from stem cells, while Israeli scientists have grown a tiny section of beating heart tissue from stem cells gleaned from human embryos.
People with type 1 diabetes have to give themselves regular injections to control blood sugar levels, as their ability to create the hormone naturally is destroyed by an immune disorder.
All but two of the volunteers in the trial, details of which are published today in the Journal of the American Medical Association (JAMA), do not need daily insulin injections up to three years after stopping their treatment regimes.
The findings were released to reporters yesterday as the future of US stem-cell research was being debated in Washington.
Stem cells are immature, un programmed cells that have the ability to grow into different kinds of tissue and can be sourced from people of all ages.
Previous studies have suggested that stem-cell therapies offer huge potential to treat a variety of diseases such as Alzheimer’s, Parkinson’s and motor neuron disease. A study by British scientists in November also reported that stem-cell injections could repair organ damage in heart attack victims.
But research using the most versatile kind of stem cells — those acquired from human embryos — is currently opposed by powerful critics, including President Bush.
The JAMA study provides the first clinical evidence for the efficacy of stem cells in type 1 diabetes. Sufferers of the chronic condition, which normally emerges in childhood or early adulthood, have to inject themselves at least four times a day.
Type 2 diabetes, which tends to affect people later in life, is linked to lifestyle factors such as obesity. There are almost two million type 2 diabetics in Briton, most of whom control their blood-sugar levels with pills or through diet.
The new study, by a joint team of Brazilian and American scientists, found that one of the first patients to undergo the procedure has not used any supplemental synthetic
insulin for three years. “Very encouraging results were obtained in a small number of patients with early-onset disease,” the authors, led by Julio Voltarelli, from the University of São Paulo in Ribeirão Preto, Brazil. write. “Ninety-three per cent of patients achieved different periods of insulin independence and treatment-related toxicity was low, with no mortality.”
Type 1 diabetes occurs when the body’s own immune system malfunctions and destroys the insulin-producing beta cells of the pancreas, causing a shortage in the hormone.
By the time most patients receive a clinical diagnosis, 60 to 80 per cent of their beta cells have been wiped out. The disease progresses from this point very quickly, and can result in serious long-term complications including blindness, kidney failure, heart disease and stroke.
Dr Voltarelli’s team hoped that if they intervened early enough they could wipe out and then rebuild the body’s immune system by using stem cells, preverving a reservoir of beta cells and allowing them to to regenerate.
They enrolled Brazilian diabetics aged between 14 and 31 who had been diagnosed within the previous six weeks. After stem cells had been harvested from their blood, they then underwent a mild form of chemotherapy to eliminate the white blood cells causing damage to the pancreas. They were then given transfusions of their own stem cells to help rebuild their immune systems.
Richard Burt, a co-author of the study from Northwestern University’s Feinberg School of Medicine in Chicago, said that 14 of the 15 patients were insulin-free for some time following the treatment. Eleven of those were able to dispense with supplemental insulin immediately following the infusion of stem cells and have not had recourse to synthetic insulin since then, he said.
“Two other patients needed some supplemental insulin for 12 and 20 months after the procedure, but eventually both were able to wean themselves from taking daily shots,” he added. One patient went 12 months without shots, but relapsed a year after treatment after suffering a viral infection, and resumed daily insulin injections. Another volunteer was eliminated from the study because of complications. The therapy, known as autologous hematopoietic stem cell transplantation, has already shown benefits to individuals with a range of auto-immune diseases such as rheumatoid arthritis, Crohn’s disease and lupus.
There are still question marks about exactly how the treatment works, and further studies will be required to fully evaluate it’s safety and efficacy.
“As a research scientist I am always hesitant to speak of a cure, but the initial results have been good and show the importance of conducting more trials,” Dr Burt said.
Given the right funding opportunities, university hospitals in London could be conducting research into the therapy within the next 12 months, he added.
“It will probably be five to eight years before we see a treatment being widely available,” he said.
In an accompanying editorial in JAMA, Dr Jay Skyler, of the Diabetes Research Institute at the University of Miami, wrote: “Research in this field is likely to explode in the next few years and should include randomised controlled trials, as well as mechanistic studies.”
Scientists Grow Human Heart Valve From Stem Cells
