Adult stem cell’s successes don’t eliminate need for embryonic stem cells
Angina relief and an artificial windpipe. No doubt about it: Stem cells have had a big week. But any time stem cells show up in the news, there’s bound to be a lot of controversy and misunderstandings.
Researchers at Northwestern University in Illinois published a study showing that stem cell injections into the heart can help reduce angina attacks, presumably by spurring the growth of new blood vessels feeding the heart. And Swedish doctors announced that they had given acancer patient a brand new windpipe grown in a lab using his own stem cells.
In each case, doctors used adult stem cells collected from the patients themselves. Unlike stem cells collected from embryos — which can theoretically be used to create any type of tissue anywhere in the body — adult stem cells are already programmed to perform one specific job.
As these recent stories show, adult stem cells can do amazing things. A windpipe isn’t the most complicated organ in the body, but being able to grow one in the lab is a big deal. And building new vessels for the heart? This sort of approach could possibly revolutionize the treatment forheart disease.
Such advances involving adult stem cell often lead to questions, criticisms and doubts about the need for embryonic stem cells, as this ABC News story illustrates. Why would doctors harvest cells from a frozen embryo when their own stem cells can perform such incredible feats?
Because, simply put, adult stem cells don’t have the flexibility and potential of embryonic cells, says Michael Gilkey, acting executive director of the Center for Stem Cell and Regenerative Medicine at Case Western Reserve University in Cleveland.
Gilkey would personally be happy if the controversy surrounding stem cell treatments just went away. “Whenever I see a new application for adult stem cells, I’m thrilled,” he says.
But while adult stem cells are useful for replacing specific tissues, embryonic stem cells still hold the most promise for more complicated rebuilding projects. For one example, the Geron Corp. recently started clinical trials of embryonic stem cells for the treatment of spinal cord injuries.
Embryonic stem cells are a relatively new frontier. While adult stem cells have been studied since the 1960s, the embryonic versions have been on the radar only since the late 1990s. In 2007, researchers shook up the stem cell picture even more with the discovery of induced pluripotent stem cells, which are adult stem cells that can be modified to have much of the flexibility of embryonic stem cells. But as Gilkey explains, it’s impossible to know if pluripotent stem cells could really take the place of embryonic stem cells in therapies of the future.
The recent breakthroughs in adult stem cells are exciting for researchers and patients alike. But the whole field of stem cells is still in its infancy. It’s too early to declare any real victories, and it’s way, way too early to shut any doors.
