Stem cells bring hope to eye patients
Macular degeneration treated
NEW YORK — Before treatment, the 51- year- old graphic artist was legally blind, unable to read a single letter on a standard eye chart. She has suffered from Stargardt’s disease, the most common form of macular degeneration in young patients, since she was a teenager, and it was getting progressively worse.
A second patient, aged 78, suffered from dry macular degeneration — the leading cause of blindness in the elderly — and could not see well enough to go shopping.
But after being treated with stem cells from a donated human embryo, both women have improved dramatically, researchers said on Monday. Stem cells are master cells that can differentiate into any of the 200 kinds of cells in the human body. Their results are the first report of the medical use of stem cells taken from human embryos, making them crucial barometers of whether the controversial technique will ever find widespread therapeutic uses.
In a paper published online Monday in The Lancet, physicians at the University of California, Los Angeles, and scientists at biotechnology company Advanced Cell Technology report the first two patients in the clinical trial suffered no adverse health effects from the treatment and seem to have benefited from it.
A week after having cells derived from a days- old embryo injected into her eye, the graphic artist could count fingers, and after one month she could read the top five letters on the eye chart. She can see more colour and contrast, has started using her computer, and for the first time in years can read her watch and thread a needle. The macular degeneration patient recently went to the mall for the first time in years.
Advocates for the blind are hailing the results. “At last we are seeing fruits of human embryonic stem cell research entering clinical trials,” said Peter Coffey, Director of the London Project to Cure Blindness.
Even scientists who support stem cell research argue they could be dangerous to use therapeutically. The property that makes them so valuable in research — stem cells can morph into any of the kinds of cells in the human body — also makes them risky.
They can form teratomas, a type of tumour that arises when stem cells differentiate into a profusion of cell types.
Another concern is that transplanting cells derived from human embryos could be rejected by the patient’s immune system. The ACT team got around that by targeting the eye, which is an “immuno-privileged” site that does not produce a strong immune response to foreign tissue.
The primary purpose of the clinical trial was to determine whether the implanted cells caused any harm. So far, neither patient has experienced inflammation, an indication that their immune system is not attacking the foreign cells.