Three separate teams of scientists Wednesday claimed to have made a breakthrough involving what has become the holy grail of stem-cell research: producing a cell that can grow into any type of tissue without destroying an embryo.
But several experts said it was unlikely that the technique would significantly alter the controversial work of California’s $3 billion stem-cell institute, which focuses on cells derived from discarded 3-to-5-day-old embryos. The experts include recipients of the institute’s grants.
Following on work done by Japanese scientists last year, the teams reported in the journals Nature and Cell Stem Cell that they had reprogrammed mouse skin cells to behave like embryonic cells, dubbed “pluripotent” because they can turn into any tissue in the body.
If the same technique can be proven to work in humans, experts said, it could revolutionize stem-cell research and help develop treatments for countless ailments without having to use embryonic cells.
“This is a very important step forward,” said Arnold Kriegstein, director of the Institute for Regeneration Medicine at the University of California-San Francisco. “These are all reputable laboratories that have essentially done the same thing.”
The teams’ studies also were hailed by some who have fervently opposed research with human embryonic stem cells, which many experts believe might prove useful for everything from generating organs for transplants to helping test drugs on numerous diseases.
“This would be a win for science, ethics and society,” said Richard Doerflinger, a deputy director for the U.S. Conference of Catholic Bishops. “It may offer a way for people of all faiths and all ethical backgrounds to study, use, subsidize and enjoy any therapeutic benefits of pluripotent stem-cell research.”
The studies also are likely to draw the attention of President Bush, who has limited federal financing of research involving human embryonic stem cells and who is expected to veto legislation passed by both houses of Congress that would ease those restrictions.
But Christopher Thomas Scott, executive director of Stanford’s Program on Stem Cells in Society, said it would be a mistake for opponents of human embryonic stem-cell research to conclude from Wednesday’s studies that embryonic cells are unneeded.
More studies needed
“To kind of claim that one study is going to do the trick isn’t the way that science works,” Scott said, because additional studies will be needed to determine if human skin cells can be reprogrammed like the mouse cells.
Similarly, several stem-cell experts cautioned against assuming from the studies that California is on the wrong road with its $3 billion stem-cell effort, which emphasizes studies with embryonic cells.
Kriegstein noted that much of the embryonic stem-cell research going on in California involves examining how to turn cells into treatments. Consequently, he said, the knowledge gained from that will be useful no matter which types of cells – embryonic or reprogrammed – ultimately are determined to be best.
Evan Snyder, director of the stem-cell and regeneration program at the Burnham Institute in La Jolla, added that it was unlikely the studies unveiled Wednesday would cause California to stop studying human embryonic stem cells. If the reprogramming concept proves to work in human cells, he said, California would be well advised to study it along with other cell techniques.
“The only way you can tell if anything is useful is to compare them all head to head,” Snyder said.
Doing comparative studies should be no problem for the California Institute of Regenerative Medicine – which was created by Proposition 71 in 2004 to oversee the state’s publicly financed stem-cell research efforts – according to its spokesman Dale Carlson.
Specifics of Prop. 71
He noted that the proposition does not require the institute to concentrate solely on human embryonic stem cells, merely that it focus on pluripotent cells. If reprogrammed human skin cells turn out to be pluripotent, he said, the institute could choose to study them, too.
The three studies built on work published last year by Shinya Yamanaka of Kyoto University in Japan. He found that he could make mouse skin cells turn into a variety of other tissue types by bolstering them with four additional genes.
Yamanaka couldn’t make them turn into every tissue type, as is possible with embryonic cells. In the studies published Wednesday, however, the teams of scientists said they added additional genetic material to the cells that made them fully pluripotent.
Other scientists also are studying possible ways to make pluripotent stem cells without destroying embryos. In August, Advanced Cell Technology of Alameda published a study in Nature that claimed it had developed a way to do that by extracting a single cell from a human embryo in a way that would allow the embryo to keep growing.
Robert Lanza, who led the study for Advanced Cell Technology, said it was too early to say whether his method, the reprogramming technique or some other procedure will prove superior for producing pluripotent cells.
“It’s exciting,” Lanza said of the studies published Wednesday. “This could truly be the holy grail.” But he added, “there are very serious hurdles left to be overcome to see if this could be used in humans. That could take years, if not decades.”
Contact Steve Johnson at sjohnson@mercurynews.com or (408) 920-5043.
