take root. Three months after they were injected, dark RPE cells ( background ) can be seen in the eyes of this patient with Stargardt macular dystrophy.
Adapted from SD Schwartz et al., The Lancet, published online (23 January 2012)
In the first published results from a clinical trial using human embryonic stem cells, two legally blind patients who received an injection of hESC-derived cells in one eye have experienced no adverse side effects and seem to have slightly better vision. Although the result is preliminary, it is an important step in the hESC field in trouble.
Since their discovery 13 years ago, hESCs have shown great promise for the treatment of diseases, but they were also pursued by security issues and ethical concerns, as deriving cells often destroyed human embryos. In the only ongoing clinical trials of hESC, the biotechnology company Advanced Cell Technology (ACT) of Marlborough, Massachusetts, derived from a type of cell called retinal pigment epithelium (RPE), which supports the light-sensing photoreceptor of the retina. Collaborators at the University of California, Los Angeles, then used these cells to treat a woman who has the dry macular degeneration and a woman in her 50s who has macular dystrophy Stargardt, an inherited disease rare. Researchers injected 50,000 RPE cells suspended in a solution in the retina of an eye of each patient.
Four months after receiving the treatment, patients have not developed tumors or abnormal growths that have sometimes been observed in animals receiving hESC-derived cells, reports the online team today The Lancet . Patients who have received immunosuppressive treatment for 12 weeks to prevent their body from attacking the cells, also showed no inflammation or other cells for signs of rejection.
The researchers detected RPE cells in the patient's eye to Stargardt's disease, but not in the patient with macular degeneration. However, the vision of two women seemed to improve, particularly in patients with Stargardt. She went to see the movements of the hand just to be able to read some letters on an eye chart. The authors caution, however, that the measurement of small visual improvements is difficult and they can not say with certainty that the changes are not the result of immunosuppressive drugs or a placebo effect.
"There is a long time to come. It is gratifying to finally see years and years of research results to the bedside," said Robert Lanza, CEO of ACT.
Other hESC researchers welcome the report, but caution that the study was very small and designed only to test the safety of the procedure. "This is an important step that will provide tremendous encouragement on the ground and [that] promises hope for many families," stem cell researcher George Daley of Harvard Medical School in Boston wrote in an email. "But ceux- these are still very early days and we have much to learn about the safety and efficacy of this new treatment before it can claim success. "
Peter Coffey of the Institute of University College London of Ophthalmology, is working on a similar treatment for macular degeneration, said the results of the security seem "very good". an immune response is less likely in the eye and in other sites in the body, and animal studies have suggested that treatment of the PRT should be safe. But "you never know until you go into the clinical setting," says Coffey. He declined to comment on the effectiveness of treatment up that the trial is completed.
Coffey is part of a trial sponsored by the pharmaceutical company Pfizer pending approval in the UK who drag a patch of hESC-derived RPE cells under the retina instead of injecting them into a liquid suspension. "We think this will work better" because the RPE cells naturally form a single layer of cells, like a carpet, said Coffey.
The ACT test continues: Employees in the UK treated a third patient on Friday. The company plans to inject different cell doses in a total of 12 patients in each trial. "Things will accelerate" now that the treatment appears to be safe, says Lanza. If the trials go well, the company will then seek to treat younger patients who should receive further treatment.
Proponents of hESC research were devastated last November when Geron, the California biotech company that was conducting the first trial using cells derived hESCs to treat injuries of the spinal cord, announced that he interrupted the trial for financial reasons. At the time, the treatment appeared safe, but the company has not seen signs of improvement in patients. Geron always follows the five patients he treated, but has not yet released any results.
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