New Stem Cell Guidelines

The National Institutes of Health (NIH) is about to change its definition of human embryonic stem cells (hESCs) in light of recent trends in stem cell research.

In March of 2009 President Barack Obama signed an executive order once again permitting the use of hESCs in research. According to the executive order, the NIH is charged with ensuring that NIH-funded research in which hESCs are used is ethically responsible, scientifically worthy, and conducted in accordance with applicable law. NIH does that by setting strict guidelines for what types of cells may be used and how they must be derived.

According to the current NIH guidelines, part of the definition of hESCs is that they are cells “derived from the inner cell mass of blastocyst stage human embryos”1. But the definition apparently had the unintended consequence of excluding some cell lines that were derived from even earlier, morula-stage cells (Review Figure 21.5 in Johnson’s Human Biology). The revised language will read, “derived from early stage human embryos, up to and including the blastocyst stage”, so that these more recent cell lines may be used in federally funded research projects.

The new guidelines do not change the rigorous ethical standards for deriving human cell lines. They just make more stem cell lines available to researchers.

1 Federal Register vol. 75, no. 35, Tuesday, Feb. 23, 2010, p. 8085-8086.