The Lancet is publishing a preliminary report on treatments using retinal cells that have been transformed from embryonic stem cells. Although the treatments are being assessed for safety not efficacy, the two patients treated for macular degeneration are reporting improvements in their sight. The injected cells attached with the patients' retinas and have shown no signs of producing tumors or transplant rejection after four months. Some of the researchers work for and the study was funded by the biotechnology company Advanced Cell Technology. The study explains the potential advantages of retinal cells derived from embryonic stem cell lines:
Although the transplantation of intact sheets and suspensions of primary RPE [retinal pigment epithelium] cells has been previously attempted, RPE derived from adult and paediatric donors are restricted in both their capacity to proliferate and their ability to differentiate in vitro. Clinically, sheets of adult RPE engrafted into the subretinal space of patients with dry age-related macular degeneration have failed to improve visual function. Although RPE derived from prenatal and postnatal tissue has been successfully dissociated and induced to grow in vitro, such sources are extremely limited and variable with regard to quality and expansion capacity. By contrast with adult and fetal tissue, a central feature of hESCs is that they have the capacity to proliferate indefinitely, providing a virtually unlimited source of youthful cells as starting material. Another crucial advantage is that the stage of in-vitro differentiation can be controlled to maximise survival and functionality.
The study concludes:
The ultimate therapeutic goal will be to treat patients earlier in the disease processes, potentially increasing the likelihood of photoreceptor and central visual rescue.
Go here [PDF] to read the study.
Addendum from the Washington Post:
In interviews with The Washington Post weeks before the results were made public, both patients said they were thrilled.
"It's a great gift, really," said the Los Angeles woman, who asked not to be named to protect her privacy. "I'm ecstatic. It's a big surprise." …
Within about six weeks of getting the cells, the Los Angeles graphic artist noticed something.
"I just woke up one morning and looked through one eye and the other and the difference was pretty dramatic," she said. "I have an armoire across my room and it has a lot of carved detail on it. I looked at it with the eye they operated on and could see all that detail. I just wanted to look at everything. It's sort of like having new eyes."
Since then, her vision has improved, enabling her to read more characters on an eye chart, thread a needle and see colors, she said.
"There's more sharpness and contrast. I recognize people better. I see their faces better," she said.
… since the procedure, she's regained enough vision to start biking again.
Whole Post article here.