June 10, 2011

Legislation Could Potentially Harm iPS Stem Cell Research

According to a new study by researchers at the Stanford University Medical Center, the Mayo Clinic and the University of Michigan, any legislation that slows human embryonic stem cell research is likely to also seriously harm the study of induced pluripotent stem cells.

The findings refute the idea that embryonic stem cell research can be abandoned in favor of the less-controversial iPS cells.

"If federal funding stops for human embryonic stem cell research, it would have a serious negative impact on iPS cell research," Stanford bioethicist Christopher Scott, citing a "false dichotomy" between the cell types, said in a statement. "We may never be able to choose between iPS and ES cell research because we don't know which type of cell will be best for eventual therapies."

Unlike embryonic stem cells, iPS cells can be created from adult tissue such as skin cells.  They look and act like embryonic stem cells, but recent research suggests there are significant differences between the two cell types that may affect how they can be used for research and eventual human therapies.

The team analyzed over 2,000 scientific papers published between 2007 and 2010.  They compared how many papers described research using exclusively human ES cells, human iPS cells, or both ES and iPS cells.

"It's always really interesting to look more closely at things that appear in the popular press," Scott said in a statement.  "We've been hearing that, since we now have iPS cells, we don't need to continue embryonic stem cell research. There's a perception that iPS cells are 'democratizing' the field because they are fairly straightforward to work with from a technical point of view."

The team found that the iPS field is dominated by well-established hES cell researchers.  Many of these researchers are publishing studies that compared hES cells with iPS cells, as apposed to focusing exclusively on one cell type.

"Although we did see a very rapid uptake of iPS cell technology during the first three years, we didn't find many new researchers moving into the field," Scott said in a statement. "The scientists who are adopting iPS quickly are the usual suspects. The old guard is working furiously to develop new iPS cell lines."

The team found that the original two papers in 2007 describing the creation of iPS cells had blossomed to 158 papers focused on iPS cells in 2010.  In contrast, human embryonic stem cell technology was adopted much slower, from the first paper in 1999 to just 12 papers in 2001.

The researchers attribute the difference in uptake of technologies to be primarily policy-driven, as scientists increasingly began to look for alternatives to the politically controversial hES cells.

However, stem cell scientists are not abandoning hES cells in favor of iPS cells.  Only three of the 15 iPS cell papers published in 2008 reported hES cell results.

"The incentives to use both types of cell in comparative studies are high because the science behind human iPS cells is still in its infancy," The researchers described in their paper. "As a result, induced pluripotent stem cells do not offer an easy solution to the difficult ethical questions surrounding embryonic stem cell research."

The team also directly polled stem cell researchers at the 2010 annual meeting of the International Society for Stem Cell Research as to their choice of cell lines.

They found that between 2008 and 2009, 55 senior authors published papers using both hES and iPS cells.  Only 14 of the senior authors published papers using iPS cells alone.

The findings suggests that iPS cell technology has not been widely disseminated as many have been expected and that senior researchers vulnerable to legislative changes affecting ES cell research continues to dominate the field.

"The deeper implications of a federal ban or restrictions on hES cell research are largely missing from the policy discussion surrounding the Lamberth decision," they write. "We now have clear evidence showing the real possibility of collateral damage caused by ill-conceived and politically motivated policy prescriptions. Restrictions, regulatory uncertainty and spurious court decisions have undoubtedly retarded progress in the pluripotent stem cell field. Now, an entirely new technology, forged out of the crucible of political controversy, stands at risk."

The study is published in the June 10 issue of Cell.


On the Net: