Breakthrough opens door to organ transplants grown in lab
by Mira Oberman
CHICAGO (AFP) - Transplantable hearts grown in petri dishes and the regeneration of amputated limbs were once the things of science fiction.
But a major breakthrough brought those dreams closer to reality Tuesday after researchers announced they were able to turn the clock back on skin cells and transform them into stem cells, the mutable building blocks of organs and tissues.
"This is truly the Holy Grail: To be able to take a few cells from a patient -- say a cheek swab or few skin cells -- and turn them into stem cells in the laboratory," Robert Lanza of Advanced Cell Technology told AFP.
"It's bit like learning how to turn lead into gold."
While the research is still in its infancy, the potential benefits are "tremendous" said Lanza, who has already found ways to cut the death rate following heart attacks in half, restore blood to limbs which would otherwise have to be amputated and construct a functioning kidney using stem cells.
The use of skin cells will eventually allow doctors to create stem cells with a specific patient's genetic code, eliminating the risk that the body would reject transplanted tissues or organs.
It also will lead to a virtual explosion in the availability of research materials used to test new drugs and understand how diseases like cancer, diabetes and Alzheimer's function.
That's because stem cells are able to infinitely replicate themselves and can be turned into any of 220 different types of cells in the human body.
But access to stem cells has been restricted because of the complications, both ethical and technical, of harvesting human embryos.
The new technique, while far from perfected, is so promising that the man who managed to clone the world's first sheep, Dolly, is giving up his work cloning embryos to focus on stem cells derived from skin cells.
"The fact that (the) introduction of a small number of proteins into adult human cells could produce cells that are equivalent to embryo stem cells takes us into an entirely new era of stem cell biology," said Ian Wilmut, the Scottish researcher who first created a viable clone by transferring a cell nucleus into a new embryo.
"We can now envisage a time when a simple approach can be used to produce stem cells that are able to form any tissue from a small sample taken from any of us."
One of the greatest advantages of the new technique is its simplicity: it takes just four genes to turn the skin cell back into a stem cell.
This, unlike the complex and expensive process developed by Wilmut, can be done in a standard biological lab. And skin cells are much easier to harvest than embryos.
The main hurdle to overcome is finding a safe way to transform the skin cells.
The current method, developed by two teams of researchers in the United States and Japan, raises the risk of cellular mutation because a retrovirus was used to deliver four genes to the cell.
While this will delay the use of these stem cells in treatment, it will not stop researchers from using the cells to study diseases and develop drug treatments.
Prior to this discovery, researchers who wanted to look at how diseases developed would usually have to study animals or organs harvested from cadavers because embryonic stem cells were so hard to use and access.
"It's an explosion of resources," Konrad Hochedlinger, of the Harvard Stem Cell Institute, said in a telephone interview. "You can take skin cells from a diabetic, turn them into pancreatic cells and figure out what happens."
The new technique could also take the heat out of the therapeutic cloning debate, said Australian researcher Alan Trounson, who was named head of the world's biggest stem cell research project at the California Institute for Regenerative Medicine.
"I think this takes the edge off that particular issue because we appear to have a way in which we can change cells into the cell type we need to study in the laboratory without using human eggs and without forming an embryo of any kind," he told Australian Broadcasting Corporation.
While incredibly promising, the new technique should not be seen as a reason to abandon controversial embryonic stem cell research, scientists cautioned.
"This new research is just the beginning -- we hardly understand how these cells work," said James Thomson of the University of Wisconsin at Madison, who led one of the two teams which made the simultaneous discoveries.
Embryonic stem cells remains the "gold standard" by which other research is measured, he said.