TORONTO - Canadian researchers have developed a new method for generating stem cells from adult human tissue, a move they believe will bring the dream of personalized regenerative medicine a step closer to reality.
  
In a study published online Sunday in the journal Nature, scientists at Mount Sinai Hospital in Toronto describe a new reprogramming procedure to transform adult cells -- such as those from a patch of skin -- into stem cells.

Like embryonic stem cells, they are "pluripotent," meaning they can give rise to almost any kind of cell in the body.

"This new method of generating stem cells does not require embryos as starting points and could be used to generate cells from many adult tissues, such as a patient's own skin cells," said principal author Andras Nagy, senior investigator at Mount Sinai's Samuel Lunenfeld Research Institute.

One of the critical components reported in Nagy's paper was developed in conjunction with Dr. Keisuke Kaji of the University of Edinburgh, whose findings are also published Sunday in Nature.

The ability to transform skin cells into stem cells isn't new. But previous approaches required the use of viruses to deliver the four genes needed to activate the cell and accomplish that task.

Nagy said using viruses poses the risk of damaging the cell's DNA, which could have unforeseen consequences.

"These four genes are very potent, very powerful factors, which also if they get loose, they could create problems," he said. "For example, they are cancerous."

To overcome that danger, Nagy's team used a snippet of DNA from, of all things, a cabbage looper moth, which delivers the genes needed to reprogram cells into stem cells. The winged creature's DNA is able to spark the transformation into stem cells in culture dishes.

"It can then be removed without leaving any trace behind.

"So it's like an organic stem cell," said Nagy of the resulting product. "And this is a big thing ... it opens up a big door or a gate to a large possible human application because we eliminated a massive risk ... from these very potent reprogramming factors after they did their job."

Nagy created Canada's first embryonic stem cell lines from donated embryos no longer required for reproduction by couples undergoing fertility treatment. Understanding how they work has played a pivotal role in developing the new method for transforming adult cells into stem cells, he said.

"The implication," Nagy said of the new research, "is that these cells could be as safe as embryonic stem cells are, because of the removal of the factors that did the reprogramming."

The next step for the team is to work with stem cells created from the cells of patients with certain diseases, such as Huntington's or Type 1 diabetes, to better understand those conditions at the cellular level.

"But the real hope is that these cells can be used in future medicine to repair damaged tissues or replace or regenerate areas that underlie the disease," Nagy said.

For instance, insulin-producing cells could be implanted in a diabetic whose pancreas no longer supplies the vital hormone, while dopamine-producing cells could replace damaged brain cells that lead to Parkinson's disease.

Eventually, scientists hope to use stem cells to repair damaged spinal cords and diseased organs like the heart, liver and kidneys -- or even to grow entire replacement organs.

And because the stem cells would be derived from a patient's own cells, there would be no need for life-long anti-rejection drugs.

"We are very enthusiastic about this," said Nagy. "We think it will have an impact on the field."

Mick Bhatia, scientific director of the Stem Cell Biology Research Institute at McMaster University, called the method "a potentially powerful tool."

"It's certainly a very important method to get reprogramming of cells because it's non-viral essentially," Bhatia, who was not involved in the research, said from Hamilton. "You can put it in, but then you can take it out."

Still, Nagy's method is not the only one recently developed to get around the problem of possibly dangerous rogue genes getting incorporated into a cell's DNA, as occurs when using the four virus genes.

But what the new method offers is perhaps a better level of control for trying to understand how the reprogramming process occurs biologically, Bhatia said.

"I think the potential of this is great, but it remains to be seen exactly what specific contributions it's going to make."