"You've got clinics springing up, taking a patient's own cells and then injecting these cells into arthritic joints, into spinal cords, into the brain. And there's really no evidence this is going to work," says Daley. "In fact, there are major concerns about safety."
The treatments could cause life-threatening infections, create tumors or trigger dangerous reactions by a patient's immune system, says Daley and other stem cell researchers.
So far the Food and Drug Administration has not aggressively regulated stem cell clinics. The reason is the stem cells being used typically come from the patient's own body — an autologous transplant. And the clinics don't process the cells much before injecting them.
But now that the treatments are being offered so much more widely, the FDA is considering more aggressive regulation. As part of that process, the agency will hold a workshop this Thursday, followed by a two-day hearing next week.
Another issue is cost. Patients are paying thousands of dollars for these treatments, which are not covered by insurance.
"We're talking about really big bucks here," says Paul Knoepfler, a stem cell scientist at the University of California, Davis, who monitors health and safety issues with stem cell clinics in his blog.
The treatments can cost from $5,000 to as much as $100,000, Knoepfler reports in an article recently published in the journal Cell Stem Cell. He estimates that there are more than 500 stem cell clinics treating as many as 100,000 patients a year in the United States.
Knoepfler hopes the FDA will crack down on the clinics.
"The FDA needs to step up its game on this, because otherwise this could continue to grow as an industry, and it's just going to put more and more people at risk," he says.
The clinics defend what they're doing.
"Patients should have access to their own body tissue," says Kristin Comella, chief scientific officer at the U.S. Stem Cell clinic, which is based in Sunrise, Fla. Comella also serves as president of the Academy of Regenerative Practices, which represents the clinics.
If patients "are able to provide and give informed consent to move forward with these treatments, that is their right," Comella says. "In particular for diseases where they have not had much success with traditional medicine."
Comella acknowledges that two of her clinic's patients suffered detached retinas after getting stem cells injected into their eyes. As a result, the clinic has stopped treating eye conditions. But otherwise, Comella says, the clinic has had no serious problems. It offers stem cell treatments for a host of conditions including diabetes, spinal cord injuries and congestive heart failure.
"There are always risks no matter what you're doing. That being said, our group has treated more than 6,000 cases and we've had very few safety events associated with these treatments," she says.
The clinics point out that the cells they are using are not human embryonic stem cells, which are controversial because embryos are destroyed to get them. And they're not induced pluripotent stem cells, which scientists create in the lab.