The stem cells used in this trial come from human embryos left over from fertility treatments. These cells have been manipulated so that they have become precursors to certain types of nerve cells. The researchers involved with the trial hope that they will travel to the site of a recent spinal cord injury and release compounds that will help the damaged nerves in the cord regenerate.
The study is what is known as a Phase I trial -- one that is designed to show only that using the stem cells in this way is safe. If the trial is a success, it will be up to future trials to show whether the treatments are effective.
Even though the research is in its preliminary stages, some stem cell researchers say it is encouraging that such trials are going forward so soon after scientists uncovered the properties of these stem cells.
"It is remarkable that only 12 years after the discovery of human embryonic stem cells, regenerative medicine therapies based this technology are entering clinical trial," Pera said. "Much of the preliminary data on the safety and efficacy of this treatment is of course proprietary, so it is difficult to assess its likelihood of success, but the entire stem cell field will be watching the progress of this trial very carefully."
Some researchers said the trial bodes well for the future of other therapies as well.
"There is great hope that these revolutionary treatments will be effective, not only in spinal cord injury but also in other diseases, including Parkinson's disease, ALS, forms of heart disease, diabetes and more," said Dr. Timothy Kamp, co-director of the Stem Cell and Regenerative Medicine Center at the University of Wisconsin Medical School in Madison. "However, it is only with such careful clinical trials that we can accurately determine if embryonic stem cell therapies truly can treat these major diseases without excessive risks."
The study and use of the cells, however, has been fraught with controversy. Opponents say it is unethical to use human embryos to make the cells and that alternatives exist.
"The press release that they have just started their human experiment may help Geron's stock price, but not science or patients," said Dr. David Prentice, senior fellow for Life Sciences on the Family Research Council, a Christian advocacy organization.
"We wish the patient well, but think Geron is irresponsible for this premature hype, given that it will be at least a year before any hard evidence that this isn't just endangering patients," he said. "Meanwhile, adult stem cells have already shown published scientific evidence documenting actual effective treatment for spinal cord injury."
However, in the months-long wait for results, proponents of human embryonic stem cell research hope for the best -- even as they prepare for all possibilities.
"This is only the first attempt and we should anticipate lots of failures before we learn how to deliver cells safely and effectively," Daley said. "I wish this brave patient well."