NEW YORK — For all the excitement, big questions remain about how to turn this week’s stem-cell breakthrough into new treatments for the sick. And it’s not clear when that will happen.
Scientists have to learn more about the new kind of cell that the landmark research produced. They have to find a different way to make it, to avoid a risk of cancer. And even after that, there are plenty of steps needed to harness this laboratory advance for therapy.
“I just can’t tell you dates,” said James Thomson of the University of Wisconsin-Madison, one of the scientists in the U.S. and Japan who announced the breakthrough Tuesday.
“The short answer is: It’s still going to be years,” Dr. John Gearhart, a stem-cell expert at the Johns Hopkins School of Medicine who was familiar with the work, said Wednesday.
Such a delay isn’t unusual. It can often take a long time for medical payoffs to flow from basic scientific findings. For example, the inspiration for a group of cystic-fibrosis drugs now being tested in people or animals goes back 18 years to a genetic discovery.
At least federal money for research into the new kind of cell won’t be a problem, said Story Landis, head of the National Institutes of Health’s Stem Cell Task Force. The task force is about to invite scientists to apply for new grants for such work, she said.
This week’s advance has apparently solved a supply problem for the study of embryonic stem cells. These cells are valued for their ability to morph into any cell type in the body. Scientists had long searched for a way to produce embryonic cells that carry the genes of a particular person.
Such cells could be used for at least three purposes. The most highly publicized one is to create transplant tissue for treating disease. In the shorter term, they could be used to create “diseases in a dish,” colonies of cells bearing illness-promoting genes that could reveal the vulnerable roots of medical conditions.
And finally, scientists could use such cells for rapidly screening potential medicines in the laboratory.
Until this week’s announcement, scientists who wanted to make such cells looked to an expensive cloning process that destroyed embryos, making it an ethical lightning rod. And it hadn’t yet worked with human embryos.
The new technique is much simpler. It makes human skin cells behave like embryonic stem cells without using embryos at all.
End of problem? Not unless these altered skin cells can truly replace embryonic cells, and that’s not clear yet, a prominent scientist says.
Paul Berg, a Stanford University Nobel laureate who helped establish federal guidelines for human research on genetically manipulated cells, said the celebration over this week’s announcement is premature.
“I’m amazed at the ethicists” saying the problem of needing embryos has been solved, Berg said. “We’re not in the clear — this is a first step.”
So what are the next steps? The first question to solve is how similar the induced-pluripotent stem cells, or iPS cells, are in behavior and potential to the embryonic cells that scientists have studied for nearly a decade. Another big question is how to make iPS cells in a different way. The breakthrough technique treats skin cells by using viruses to carry in a quartet of genes. Those viruses disrupt the DNA of the skin cells. When that happens, there’s a risk of cancer.
