CHICAGO (AFP) - Researchers came a step closer to finding a safe way to use stem cells in clinical treatment Thursday when a team of Japanese scientists announced they found a way to induce stem cells without triggering tumors.
Stem cells are considered a potential magic bullet cure for a host of diseases because they can be transformed into nearly any cell in the body and used to help replace damaged or diseased cells, tissues and organs.
However, stem cell research is highly controversial because, until recently, viable human embryos were destroyed in the process of extracting the most flexible stem cells.
Two groups of scientists recently bypassed this problem by transforming human skin cells into stem cells which had the same properties as embryonic stem cells.
This offered the promise of treatments tailored to the specific genetic code of a patient -- anything from blood transfusions to transplantable organs grown in a petri dish -- without the need for harmful drugs to prevent rejection.
But the skin cells were regressed using a method which caused tumors and the potential for genetic mutation, which meant those induced pluripotent stem cells, or iPS, were not safe for clinical use.
One of those teams has now managed to induce stem cells without causing tumors and in a way which may not cause as much genetic disruption.
They again used a retrovirus to introduce four genes, this time experimenting with adult mouse liver and stomach lining cells.
Mice implanted with these induced pluripotent stem cells remained tumor free after six months, according to the study published online in Science Express.
And the researchers showed that the retrovirus did not need to burrow into the adult cell genome at a specific sites. This could help scientists develop avoid viral integration at sites prone to trigger tumors.
While the results are promising, there is still much work to be done, said lead researcher Shinya Yamanaka of Kyoto University.
"It still takes years of basic researches before we become able to use iPS cells to treat patients," Yamanaka said in an e-mail.
"We are doing our best to bring it to clinics as quick as possible."