Exciting news! Researchers at UCLA and Advanced Cell Technology have published the first report (.pdf) of the use of human embryonic stem cell therapy for blindness caused by a condition called macular degeneration. The preliminary report indicates that the cells are well-tolerated and appear safe. Although the two trials were not designed to test whether the cells can improve vision, the investigators were encouraged by the fact that the two trial participants did not show any further vision loss during the first four months of the trial and the vision of one participant seemed to improve. In an article published in The Lancet today, the authors wrote:
We noted clear functional visual improvement in the study eye of the patient with Stargardt’s macular dystrophy corresponding subjectively to the transplanted region of the posterior pole. At baseline the central vision was hand motions. By week 2, best corrected visual acuity was improved to counting fingers (one ETDRS letter). We recorded continued improvement during the study period (five ETDRS letters [best corrected visual acuity 20/800] at 1, 2, and 3 months; table). The patient is very reliable and worked for years as a graphic artist. She reports subjectively improved colour vision and improved contrast and dark adaptation from the operated eye.
Before implantation, the stem cells were coaxed to become cells that form the retinal pigment epithelium - the tissue that is compromised in both dry age-related macular degeneration and Stargardt's macular dystrophy. The newly derived epithelial cells were then transplanted into two patients, where they integrated and survived over time. They appeared to grow normally after transplantation.
Much more work needs to be done, of course, before any conclusions can be made about the potential usefulness of these cells as therapy. But I imagine that proponents of human embryonic stem cell research are breathing a cautious sigh of relief this morning. After Geron abruptly dropped their hESC trial for spinal cord injury last November, researchers and media people alike wondered aloud whether the move would set the field back irreversibly. This news, however preliminary, must be welcome indeed.
(If you'd like to learn more about Advanced Cell Technology and their chief scientific officer, Robert Lanza, MD, check out this fascinating history of the company published in Nature earlier this month.)