Wednesday, March 24, 2010

Human Embryonic Stem Cells: Steps Back, Steps Forward

[published with Andrea Ballabeni in the World Congress for Freedom of Scientific Research the bulletin, Number 10 (March 2010)]

The scientific and political fate of human embryonic stem cells (hESC) is unsteady. In 2010, their use is still contested, and lab research suffers from that. It is increasingly clear that researchers need them, want to use them, and plan to use them for a long time. While some hailed human induced pluripotent stem cells (hiPS) as the way forward the regenerative medicine, the belief that hiPS and hESC are truly equivalent is slowly eroding. The unequivocal title of a Science commentary on the evidence on hiPS/hESC alleged equivalence tells it all: 'Reprogrammed Cells Come Up Short, for Now.'

In the United States, researchers' expectation finds support in policy. The Obama administration did not hold back its promise to facilitate research with hESC. The restrictions imposed by the Bush administration are gone. Yet, the obstacles and uncertainties still affect investigators. The Obama policy rightfully makes it a requirement for researchers to show that the couple who donated the embryos for the lines creation was fully informed of other options. Such evidence is lacking for several cell lines that were already in existence in 2001, when Bush limited federal funding of hESC. On March 15 2010, the Washington Post reported that ''[s]o far, the NIH has approved 43 lines. But that includes only one of the original 21 'Bush' lines. An additional 115 lines are awaiting review. But that includes only two more of the original lines.'' As a consequence, researchers face uncertainty, an uncertainty that is particularly troublesome with regard to the cell lines that were funded under the Bush era. These cell lines are the bedrock of countless protocols, and the prospect of losing them would result in a significant step back as many projects would have to start from scratch with new cells as opposed to building upon the existing.

The problem is evident, and some have proposed that the NIH revises its guidelines ''to grandfather in the existing lines or give researchers a two-year grace period to continue to work with them until they get formal approval.'' To us, even more appealing, and ultimately very reasonable, would be the proposal that all Bush-era cell lines are approved without further ethical scrutiny. After all, the ethical concerns must be relatively minor as these lines had been deemed 'acceptable' by the clearly conservative gatekeepers appointed by former President Bush. Some of the answers needed by researchers may come from the proposed expansion of the definition of hESC for the purpose of NIH funding. The NIH proposes redefining hESC as:

… pluripotent cells that are derived from early stage human embryos, up to and including the blastocyst stage, are capable of dividing without differentiating for a prolonged period in culture, and are known to develop into cells and tissues of the three primary germ layers.
While the current definition limits hESC to cells taken from the inner layer of a blastocyst (5–6 days after fertilization), the new definition will also include cells taken from a morula, the developmental stage that come before a blastocyst is formed (3–4 days after fertilization). While most researchers are not currently using morula-derived cells, the tweaking of the definition of hESC may be a significant step for two reasons. First, morula-derived cells and blastocyst-derived cells are most certainly biologically different. Thus, unique data will flow from the newly funded research. Second, morula-derived hESC lines may be derived without the need to suppress the entity—the solid ball of 4-16 cells contained within the zona pellucida. This procedure is arguably 'more ethical' as Lanza recently pointed out. The new definition should take away some ammunition from the ever vigilant critics of hESC, thus making access and use to hESC less unsteady.

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