News this week that Japanese and American scientists have found a third way to make pluripotent stem cells — a process that’s far simpler, faster and cheaper — is being heralded by some as a game-changing development in regenerative medicine. Others say it may just be “a lab curiosity.”
Until now, there have been two main ways to create stem cells that are pluripotent (capable of producing any cell the body needs):
• harvesting them from embryos (embryonic stem cells), or
• reprogramming adult cells to function like embryonic stem cells (induced pluripotent stem cells).
Making embryonic stem cells has not been without controversy. And because creating induced pluripotent stem cells initially involved genetically altering things, there were concerns they could potentially cause tumours. While that problem apparently has been solved, the procedure is still a complex and costly one.
Now there is a third way — although, so far, it has only been done in animals. Researchers at the RIKEN Center for Developmental Biology in Japan and Brigham and Women’s Hospital and Harvard Medical School in the United States transformed blood cells from newborn mice into pluripotent cells called STAP cells. The technique involves stressing the cells by exposing them to trauma, low oxygen levels or mildly acidic solutions. Within days, the cells revert to an embryonic-stem-cell-like state. (A Boston Globe graphic illustrates the process beautifully. See it here.)
“It’s very simple to do,” Dr. Charles Vacanti of Brigham and Women’s Hospital in Boston, told the Associated Press after the two papers were published online Wednesday in Nature. “I think you could do this actually in a college lab.” Dr. Haruko Obokata of the RIKEN Center, said researchers are already at work to see if the technique can be replicated with human cells.
So, what to make of these new stem cells?
Dr. Chris Mason, chair of regenerative medicine bioprocessing at University College London, told Reuters that the approach was “the most simple, lowest-cost and quickest method” to generate pluripotent cells from mature cells. “If it works in man, this could be the game-changer that ultimately makes a wide range of cell therapies available using the patient’s own cells as starting material – the age of personalized medicine would have finally arrived.”
Others are more guarded. “Until you show it works in humans, it’s hard to know what the application is going to be,” the University of California’s Dr. William Lowry told AP. “For now, the question of whether it’s a lab curiosity or a big medical benefit; that’s still up in the air.”
To make sense of STAP, NewsDesk asked Dr. Janet Rossant (pictured above), Chief of Research and Senior Scientist at The Hospital for Sick Children for her assessment of this remarkable development.
“I don’t think it’s a game-changer,” says Dr. Rossant, President of the International Society for Stem Cell Research and one of the world’s leading embryonic stem cells scientists. “A game-changer means we’re all going to suddenly stop what we’re doing and do something else. It’s a surprising and intriguing observation, suggesting that somehow there is an intrinsic pluripotency program that is sitting there, waiting to be revealed if we stress the cells.”
She describes this as “one of those findings where you go, ‘Hmmm, that’s interesting.’ Of course, this is all mouse, so there is a need for further replication by other groups and further explanation of what the mechanism is. And, of course, extension to the human situation if this is going to have practical relevance. As it stands, I don’t see people are suddenly going to stop making induced pluripotent stem cells by the standard route. Because these cells, whatever they are, are not exactly identical to embryonic stem cells.”
The really important thing, according to Dr. Rossant, is that this discovery shows there “are multiple states of pluripotency out there” to be investigated. “We need to understand more about what we mean by the pluripotent state and whether it is a state that (cells) can fall back into.”
The true test of induced pluripotent stem cells, which were discovered in 2006 and earned Japan’s Dr. Shinya Yamanaka a Nobel Prize, was the fact other labs around the world could replicate the results. That will now be the challenge for STAP cells.
“It was a very surprising, intriguing result. It’s come from a reputable laboratory — RIKEN is one of the top developmental biology groups in the world,” says Dr. Rossant, who is a member of the Canadian Stem Cell Foundation’s Science Leadership Council.
“The question will be, ‘Is this a truly robust way of generating pluripotent stem cells?’ And only time will tell.”