Reuters is reporting that Advanced Cell Technology has enrolled the first two patients for its experiments on human eyes using injected embryonic stem cells. The report says that one patient each has been signed up for its two experimental trials that were approved within the past seven months by the FDA; the patients were recruited at the Jules Stein Eye Institute, UCLA.

Information on the experimental patient trials for Stargardt's macular dystrophy and for age related macular degeneration says that each experiment is approved to enroll 12 patients, successively, with different doses of embryonic stem cell derivatives being given to groups of three patients each. These safety trials are scheduled to go through July 2013, but there is no other information about how long the patients will be monitored for potential tumor formation caused by the injected embryonic stem cell derivatives. Beyond the ethical problems associated with embryonic stem cells--requiring destruction of young human life to derive the cells--there is significant concern about the practical problem of controlling the cells' growth. Embryonic stem cells have a disturbing tendency to grow and form tumors, even in instances when the cells had supposedly stopped growing, and in animal studies injection of as few as two growing embryonic stem cells was sufficient to cause problems.

A competing company, Geron, has so far injected two patients with derivatives of embryonic stem cells in its own human experiments, the first approved in the world. Because embryonic stem cells are difficult to impossible to control, safety is a significant and non-trivial, concern for the patients, and Geron has committed to follow the injected patients for 15 years.

Meanwhile, over 2,100 adult stem cell clinical trials are ongoing or completed. Adult stem cells are used to treat over 50,000 patients around the globe each year, and have shown published success for patients with dozens of different diseases and injuries, including for spinal cord injury, for corneal blindness, for juvenile diabetes, for heart damage, and for multiple sclerosis, just to name a few. Check out just a few of the adult stem cell success stories.