Stem cells show promise in treating blindness

A medical breakthrough was reported Monday in the journal The Lancet wherein the results of a therapy using human embryonic stem cells in two legally blind patients was described.

Intended as a safety test, the experiment reported more than a decade of debate over human embryonic stem cells. Seen as a potential treatment of diseases such as diabetes and blindness, the therapy has also drawn criticism from conservative groups that have decried the cells' origins — removed from early human embryos that are destroyed in the process, and then grown into colonies for research.

“We're showing these cells indeed seem to be safe and help patients,” says study senior author Robert Lanza of Advanced Cell Technology in Marlborough, Mass., which funded the study. University of California, Los Angeles, surgeons on the study team last year injected 50,000 cells each into one eye of two women suffering untreatable forms of macular degeneration, a progressive blindness that afflicts more than 8 million people nationwide.

The stem cells were derived from an embryo in a fertility clinic that a couple had chosen not to use to start a pregnancy and was going to discard, Schwartz said. According to Dr. Robert Lanza, the embryo was destroyed after the stem cells were derived, but in the future, doctors will be able to derive stem cells from an embryo without destroying it.

Four months after the injections, neither study patient had lost vision, as usually happens in progressive blindness, or showed signs of abnormal growth in their eyes, quelling fears associated with the cells that they could give rise to tumors. One patient with Stargardt's macular dystrophy, a common form of blindness in kids, saw demonstrably improved vision, while the other patient's improvement looked more ambiguous. She also seemed to be seeing better in her uninjected eye. “I'm thrilled and so excited,” said their ophthalmologist, Dr. Steven Schwartz, at UCLA's Jules Stein Eye Institute. “We're not saying we found a cure for blindness, but this is a big step forward for regenerative medicine.”

Before her stem cell surgery in July, Sue Freeman, 78, couldn't take a walk, go shopping or cook by herself because of macular degeneration, a disease that affects millions of Americans and for which there is no cure. Now, after surgery in one eye, she cooks, shops and walks on her own. The second patient in the study, a 51-year-old woman who preferred not to use her name, said she first noticed a change in her vision a few weeks after surgery when she woke up one morning and looked at an armoire across her bedroom. Later, she noticed she could see the knobs on her stove, which she couldn't see before at a certain distance. Before having the surgery, the patient couldn't read any of the letters on an eye chart with extra large letters for people with vision problems, but after the surgery, she could read five letters on the chart, according to the study. Before the surgery, she couldn't see how many fingers an examiner was holding up in front of her face, but afterward she could.

The patients showed improvement of the macular degeneration was called mostly psychological by experts because the vision in one of the women’s untreated eye appeared to get better too. The study noted that surgeries sometimes produce false “placebo” benefits for patients. However, the study shows new retinal cells growing in places affected by blindness in the patient's eyes.

“Ten years ago we told these patients they were going to go blind. These results show a lot of promise to change the landscape,” says retinal surgeon Rama Jager of University Retina in Oak Forest, Ill., who was not part of the study. Growth of new cells in the patients' eyes seen in the study is “really spectacular,” Jager says. “You just don't see that in these patients.”

However, biologist David Prentice of the Family Research Council in Washington D.C., a past critic of embryonic stem cell research, called the results, “way too early, and way too few patients to call this safe.”

In a commentary in The Lancet, Dr. Anthony Atala, director of the Institute for Regenerative Medicine at Wake Forest School of Medicine, warned that the report was preliminary, in only two patients, and with a short-term follow-up. “But the results are impressive, especially considering the progressive nature of both diseases,” he added. In his commentary, Atala said induced pluripotent stem cells, which can be made without destroying an embryo, may also be useful. These cells, which have been derived from skin, can be derived directly from a patient, making anti-rejection drugs unnecessary.

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.

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