RECENTLY ROBERT LANZA of Advanced Cell Technology made the extraordinary claim that he had succeeded in finding a way to culture embryonic stem cells from a single cell extracted from an embryo without destroying the embryo itself. If this can really be done it can avoid one ethical challenge to embryonic stem cell research. But was this really done? The Washington Post on September 6 published an article describing Sen. Specter and Sen. Harkin’s scathing criticism of Robert Lanza’s research, saying that his group had in fact destroyed the embryos. So what is going on? In order to determine this I first trekked back to the journal Nature to read the original letter (I. Klimanskaya et al. Nature doi:10.1038/nature05142; 2006).

Initially it is hard to determine exactly what was done, since the article is a letter, a short write-up, and not a full article with extensive supporting information. However, with a little basic math things become clear. They started with 16 embryos and grew them up to 8-10 cells. They then removed single blastomeres from the embryos and cultured these. Later in the paper we find that 91 blastomeres total were removed. Obviously 91 cells cannot come from 16 embryos if only one cell is removed from each, therefore multiple cells were removed from each embryo and the embryos were destroyed.

The authors go on to say that out of 91 cells two of these were successfully cultured. These two came from 35 blastomeres collected from the six grade I or II embryos, which are healthier than the grade III embryos that were the source for the remainder of the blastomeres (grades IV and V were not used). Obviously then the efficiency of this procedure is low at this point and highly dependent on the health of the original embryo.

My next question was how people got the idea that these embryos were not destroyed. For this I turned to the current issue of Nature and its article “‘Ethical’ stem-cell paper under attack” (A. Abbott. Nature 443, 12, (2006)). Apparently in Nature’s August 24th podcast (mp3 file, text, and clarification available from this page). Robert Lanza said, “What we have done, for the first time, is to actually create human embryonic stem cells without destroying the embryo itself.” Oops. Not true! Nature itself also published a press release stating that only one cell was taken from each embryo, although they should have realized this wasn’t so, and indeed rapidly corrected the error. So does that mean this research is useless? Not at all.

While Lanza’s group did not remove one cell and leave the embryo to grow further, it is already known that a human embryo can survive if only one cell is removed. This is done all the time for genetic testing in IVF. What Lanza’s group demonstrated is that a single cell culture can produce a viable cell line. This is the new discovery. Moreover, he provides evidence from several studies that these single cells are incapable of themselves developing into a new embryo, thus removing another ethical roadblock.

This opens the door for retrieval of a single cell from an embryo used for IVF, using this cell to culture an embryonic stem-cell line, and implanting the original embryo to develop normally. At the moment the efficiencies are far too low to make this even remotely practical, but no doubt further research with refine the method.