For the first time, researchers have results from a test of an embryonic stem cell treatment in people.
In the study, the treatment appeared to be safe, and modestly improved the vision of two patients who were legally blind. However, the results are very preliminary.
The researchers modified human embryonic stem cells to produce eye cells, which were transplanted into two patients who had lost their vision due to macular degeneration.
After four months, there were no signs of cancer formation or immune rejection of the cells, both potential complications of stem cell therapy.
Vision tests suggested the patients' vision improved. One patient went from being able to see only hand movements, to being able to see movements of individual fingers, the researchers said. The other patient went from being able to read 21 letters on a chart to being able to read 28 letters.
"Despite the progressive nature of these conditions, the vision of both patients appears to have improved after transplantation of the cells, even at the lowest dosage," study researcher, Dr. Robert Lanza, chief scientific officer at Advanced Cell Technology, a biotechnology company in Marlborough, Mass., said in a statement. "This is particularly important, since the ultimate goal of this therapy will be to treat patients earlier in the course of the disease where more significant results might potentially be expected," Lanza said.
Continued follow-up of the patients is needed, the researchers said. It's not clear whether the patients' vision may change over time, or if complications may develop.
Human embryonic stem cells give rise to virtually any cell in the human body, but their use in medicine has been controversial, because obtaining these cells requires the destruction of human embryos.
The findings are "exciting," and are a first, saidJoshua Hare, director of the Interdisciplinary Stem Cell Institute at the University of Miami Miller School of Medicine. However, the study was very small, and it's possible any improvement seen were due to the placebo effect, Hare said.
"The jury is still very much out on whether or not this is going to be a cure," for patients with macular degeneration, Hare said.
The study is published today (Jan. 23) in the journal the Lancet. It was funded by Advanced Cell Technology.
Pass it on: A treatment with cells derived from human embryonic stem cells may improve vision in some patients with macular degeneration.