Reflections on the latest guidelines for stem cell research

By Thomas H. Rosenquist, Ph.D.

I have the following brief comments about the July 7, 2009 National Institutes of Health (NIH) guidelines for the use of human embryonic stem cells, from the perspective of a scientist who has carried out research for 25 years in early embryonic development and the fate of stem cells and a research administrator charged with facilitating growth of the University of Nebraska Medical Center (UNMC) research enterprise. I have not made any specific comments about the need for continuing utilization of human embryonic stem cells.

Overall, I am very pleased with the potential facilitation of stem cell research that is inherent in the application of these new guidelines. There a few key features of these guidelines that are worthy of special mention, in my opinion.

Positive

The science and technology of derivation of human embryonic stem cells has advanced dramatically since the Bush-approved lines were derived in 2001 or before. For example, the Bush-approved lines were grown in the presence of nonhuman animal cells or animal cell products that were contaminants, making the cells ineligible for human therapeutic use, and whose impact upon the outcome of experiments was unpredictable.

Stem cell lines growing in culture have a finite usable life. The Bush-approved lines were essentially worn out. Under the current guidelines, there will be a dependable source of new cell lines. In addition, widespread donation of excess blastocysts prepared for in vitro fertilization will help assure a broad genetic variation in the cell lines.

While new cell lines and research that utilized them has continued since 2001 with funding from sources other than NIH, the NIH is the biggest and most dependable, productive source of new basic biomedical research data in the world. Thus, opening the door to vastly expanded NIH-funded stem cell research will result in an explosion of data that will hasten the therapeutic and life-saving application of stem cells. Lives will be improved; lives will be extended; lives will be saved.

The informed consent process for donors, and the other assurances given in these guidelines, are remarkably comprehensive, much more so than had been the case with the Bush-approved lines. Thus, the majority of Americans who approve of the donation and utilization of cells from in vitro fertilization clinics can be comfortable with the highly principled regulation of this process, and can be assured that many more of the excess donated embryos will be given their only chance to survive and contribute to the well-being of humanity within an orderly and ethical process.

Negative

Because there is less consensus for the creation and research application of embryonic stem cells derived from somatic cell nuclear transfer or from gametes (egg or sperm) without fertilization (parthenogenesis), these kinds of research may not be carried out with NIH dollars. Our loss: These also are fertile research areas that need to have the large-scale basic science examination that is possible only with NIH support.

The guidelines stipulate that the eligible cell lines must be “capable of dividing without differentiating for a prolonged period in culture,” but the period is not specified and the medium in which the cells must be placed to keep them undifferentiated is not specified. Embryonic cells are highly sensitive to external signals; although there are certain media that are typical for these situations, it is virtually impossible to predict how a given set of cells might react upon their initial placement in culture. Thus this rule may be ambiguous; see also the next “negative,” which is related.

The guidelines stipulate that the eligible cell lines must be “known to differentiate into cells and tissues of the three primary germ layers,” but some cell lines may be especially useful because they differentiate into only one of the germ layers (e.g., the layer of the embryo that ultimately differentiates into nerve cells). This rule seems superfluous; it doesn’t seem to me that there is any ethical principle violated by the unexpected behavior of a cell line that is derived with great scientific and regulatory care.

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