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NRL News
Safer Way
to Produce Stem Cell Alternative Demonstrated In two studies published in the journal Nature, scientists working at the universities of Edinburgh and Toronto have found an ingenious new way to more safely reprogram adult stem cells, providing a virtually limitless supply of embryonic-like stem cells. The alternative cells are known as iPS (induced pluripotent stem) cells. The technique for producing them was first reported in November 2007 by researchers in Japan and America. But there was a problem. The clock on adult skin cells was rewound, so to speak, creating cells that “appear biologically identical to embryonic stem cells,” as the Washington Post’s Rob Stein put it. This was accomplished by injecting them with a virus carrying four extra genes. But as the Toronto Star explained in its excellent story, “the virus disrupts the cell’s DNA and may trigger cancer.” So the search was on for another way to reprogram cells. Last year Andras Nagy and a team of scientists at Mount Sinai Hospital in Toronto started to investigate a new reprogramming method. Soon afterwards they began collaborating with a group led by Keisuke Kaji at the University of Edinburgh, according to the Star. “In the new work, Nagy and his colleagues in Toronto and at the University of Edinburgh in Scotland instead used a sequence of DNA known as a transposon, which can insert itself into the genetic machinery of a cell,” Stein reported. “In this case, the researchers used a transposon called ‘piggyBac’ to carry four genes that can transform mouse and human embryonic skin cells into iPS cells.” The key innovation is that “[a]fter the conversion took place, the researchers removed the added DNA from the transformed cells using a specific enzyme.” “This double sequence of non-virus delivery and complete removal of growth factors is what makes the finding so important for future research on patients,” the Star reported. “Nagy likens the process to a space shuttle ditching its rocket once the fuel has burned up and the shuttle has reached space.” Also hugely important is because the iPS cells are made from the patient’s own skin cells, there is no risk of attack by the immune system. “I was very excited when I found stem cell-like cells in my culture dishes. Nobody, including me, thought it was really possible,” Kaji told the Guardian. “It is a step towards the practical use of reprogrammed cells in medicine, perhaps even eliminating the need for human embryos as a source of stem cells.” Stein provided quotes from two well-known researchers. “It’s very significant,” said George Q. Daley, a stem cell researcher at Children’s Hospital in Boston. “I think it’s a major step forward in realizing the value of these cells for medical research.” “It’s very exciting work,” agreed Robert Lanza, a stem cell researcher at Advanced Cell Technology in Worcester, Massachusetts. “With the new work, we’re only a hair’s breadth away from the biggest prize in regenerative medicine—a way to create patient-specific cells that are safe enough to use clinically.” Naturally, some, while praising the research, insisted that work on embryonic stem cells research should continue. But what is clear is that the field of ethically acceptable alternatives is progressing by leaps and bounds. The following quote says it all. “Stem cell research that requires destroying embryos is going the way of the Model T,” Richard M. Doerflinger of the U.S. Conference of Catholic Bishops told Stein. “No administration that values science and medical progress over politics will want to divert funds now toward that increasingly obsolete and needlessly divisive approach.” |