Stem Cell Breakthrough Uses Human Skin, Not Embryos
In a major breakthrough, scientists announced this week that they have generated stem cells from human skin which could help in the fight against major diseases and sidestep the battle over using embryonic cells.
The discovery opens the door for promising research into using the blank-slate stem cells to test new drugs and study how diseases function without being forced to destroy embryos in the process, which has led to legal restrictions on research in the United States.
The researchers in Japan and the United States have also eliminated a major hurdle to using stem cells in treatments. The stem cells could eventually be generated with a specific patient’s genetic code, eliminating the risk that the body would reject transplanted tissues or organs.
The new method is expected to rapidly advance research in the treatment of cancer, Alzheimer’s and Parkinson’s diseases, diabetes, arthritis, spinal cord injuries, strokes, burns and heart disease because scientists will have much greater access to stem cells.
“(The) work is monumental in its importance to the field of stem cell science and its potential impact on our ability to accelerate the benefits of this technology to the bedside,” said Deepak Srivastava, director of the Gladstone Institute of Cardiovascular Disease.
“Not only does this discovery enable more research; it offers a new pathway to apply the benefits of stem cells to human disease.”
Stem cells are seen as a possible magic bullet because they can be developed into any of the 220 types of cells in the human body.
But research has been limited in the United States because of ethical concerns, and very few labs have had the resources and technical expertise to work with embryonic stem cells.
The new method is fairly straightforward and can be repeated by standard labs with relative ease, said study author James Thomson of the University of Wisconsin at Madison.
“My personal barometer of optimism has gone up a lot,” Thomson said in a conference call.
“Funding is finally going to go up because this does remove the political debate. And as we engage more and more people in the United States things are going to accelerate.”
The White House hailed the discovery as a means of solving medical problems “without compromising either the high aims of science or the sanctity of human life.”
Two teams of researchers were simultaneously able to transform the skin cells by using a retrovirus to insert four different genes into the cells.
The Japanese team, led by Shinya Yamanaka of Kyoto University, managed to produce one stem cell line out of every 5,000 cells.
“This efficiency may sound very low, but it means that from one experiment, with a single ten centimeter dish, you can get multiple iPS (induced pluripotent stem) cell lines,” he said, referring to a stem cell type capable of creating any type of cell in the body except those of the placenta.
The US team, led by Thomson, reprogrammed one of every 10,000 cells but did so without the use of a gene that is known to cause cancer.
Both techniques have the risk of mutation because the cells retained copies of the virus used to deliver the genes.
The crucial next step is to find a way to switch on the genes that cause the skin cells to regress into stem cells rather than relying on the retrovirus to insert the genes.
“It’s almost inconceivable at the pace this science is moving that we won’t find a way to do this,” stem cell researcher Douglas Melton of Harvard University told Science magazine.
The ability to design patient-specific and disease-specific stem cells ought to help push research forward even before the mutation risk is eliminated.
“These cells should be extremely useful in understanding disease mechanisms and screening effective and safe drugs,” Yamanaka said. “If we can overcome safety issues, we may be able to use human iPS cells in cell transplantation therapies.”
While the skin cells may eventually prove to be more useful than embryonic stem cells, Yamanaka cautioned that it would be “premature to conclude that iPS cells can replace embryonic stem cells.”
“We are still a long way from finding cures or therapies from stem cells and we don’t know what processes will be effective,” he added.
Thomson cautioned it could be a couple years before researchers resolve all the problems with iPS cells and can confirm that they do not eventually act differently than embryonic stem cells.Filed under: Headlines