- The Washington Times - Monday, July 19, 2010

Reprogrammed adult stem cells may not be as useful as first hoped as an alternative to the more controversial embryonic stem cell research, researchers found in articles published Monday.

Researchers at Children’s Hospital Boston and Johns Hopkins University published an article online in the prestigious journal Nature, that such adult stem cells are still fundamentally different than embryonic cells when transferred in curing diseases.

Many in the medical community and among pro-lifers have hoped harvesting embryonic cells, which destroys the days-old human embryos and has provoked intense ethical and moral criticism, could be avoided by manipulating adult cells to act as if they were embryonic stem cells.

Called “pluripotent cells,” the altered adult cells “forget” they were once cells naturally “programmed” to become liver cells, lung cells, skin cells, etc. This would make them, theoretically, as useful as embryonic cells for a variety of miracle cures, especially for degenerative diseases such as Alzheimer’s.

It turns out, the study says, that they don’t forget.

“Our data indicate that nuclear transfer [from embryonic cells] is more effective at establishing the ground state of pluripotency than factor-based reprogramming [of adult cells], which can leave an epigenetic memory of the tissue of origin that may influence efforts at directed differentiation for applications in disease modelling or treatment,” the article’s findings stated.

Kitai Kim, a postdoctoral fellow and one of the leading researchers on the project, explained that older sells are more set in their ways and difficult to reprogram. His group worked with mice, reprogramming different kinds of cells with varying results.

The needed DNA change “was incompletely reset in [reprogrammed adult] cells compared to nuclear transfer stem cells,” said co-senior author Andrew Feinberg. “This paper opens our eyes to the restricted lineage of iPS cells. … The lineage restriction by tissue of origin is both a blessing and a curse. You might want lineage restriction in some cases, but you may also have to do more work to make the iPS cells more totally pluripotent.”

A second, separate group  of scientists led by Konrad Hochedlinger, a stem cell biologist at Massachusetts General Hospital Center for Regenerative Medicine, published similar findings Monday in Nature Biotechnology. That group said the adult cells, scientifically known as Induced Pluripotent Stem Cells (iPS or iPSC), obtained from mice exhibited distinct patterns that could not be erased.

Some wonder if the findings will re-ignite the debate over whether federal research dollars should go toward studying some somatic cell nuclear transfers, or embryonic cells. Researchers said the findings demonstrate that the scientific focus needs to be on embryonic stem cell research.

The research did show, however, that while reprogrammed stem cells may not be as versatile as embryonic ones, they can still be quite useful.

Thousands of patients around the world have been treated with adult stem cells, but no humans as of yet have been given cells derived from embryos in an approved trial.

At the beginning of 2009, Geron Corp., a California-based company, announced it would begin the first embryonic stem-cell study in humans, but that has been put on hold by the FDA.