New ethical stem cell production technique confirmed

Dec 7, 2007 / 09:24 am

Researchers said on Thursday that they had proven in principle a new type of stem cell could be used as therapy after they used the cells to treat mice with sickle cell anemia, Reuters reports.

A team at the Whitehead Institute of Biomedical Research in Cambridge, Massachusetts used stem cells created from skin cells to treat mice engineered to have sickle cell anemia, a blood disease caused by a defect in a single gene.

The pioneering technique avoids using embryonic stem cells, which are produced by cloning an adult cell and then destroying the resulting embryo.

"This is the first evaluation of these cells for therapy," said Dr. Jacob Hanna, who worked on the study. "The field has been working for years on strategies to generate customized stem cells," he added in a telephone interview.

The new technique, developed by US and Japanese researchers, reprograms skin cells to behave like embryonic stem cells.  Four genes, what one researcher calls the “magic four factor,” are inserted into the skin cells to trigger the change.  The new stem cells are called induced pluripotent stem cells, or iPS cells for short.

Rudolf Jaenisch, a member of the Whitehead Institute, noted in a statement the technique’s potential: "This demonstrates that iPS cells have the same potential for therapy as embryonic stem cells, without the ethical and practical issues raised in creating embryonic stem cells."

The technique is in need of further study to resolve potential problems.  One difficulty is that the “magic four factor” genes are delivered using retroviruses.

"Once they enter the genome, there is the danger that they can silence some genes that are important or they can activate some dangerous genes that shouldn't be activated," Hanna said.

In addition, one of the four genes used is known to cause cancer, though the gene is removed after the cells are reprogrammed.

Hanna and other researchers said experimentation on human embryonic stem cells should continue.  "They are the gold standard for what is normal and how a stem cell should behave," Hanna said.

However, this method is opposed by the Catholic Church and pro-lifers because it relies on the destruction of a human embryo.

Stem cell researchers hope to treat many diseases like diabetes, Parkinson’s disease, and spinal cord injuries.  Stem cell therapies created from a patient’s own cells would use genetically identical cells, thus avoiding immune system problems.