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04/24/2014

Last Week’s Stem Cell Cloning News

Readers of this blog probably saw last week’s report, as the NPR headline put it, that “First Embryonic Stem Cells Cloned from a Man’s Skin.”  I was able to read the full text of the online publication, by Cell Stem Cell, here.

The stated goal of the work is to use somatic cell nuclear transfer (SCNT) to clone an embryo that can then be used to develop embryonic stem cells (ESCs) that are pluripotent—able to differentiate into any cell type in the human body—and coax them to differentiate as needed for use as a cell-based treatment for disorders where replacement cells might be helpful; e.g. heart failure, neurodenerative disease, or others.  In SCNT, an egg, donated by a healthy woman, is needed; its nucleus is removed and replaced with the nucleus from tissue (such as skin) from the person who would be treated.  With the necessary manipulations in the lab, an embryo is formed that can be used while it is still just a few days old to obtain the desired ESCs.  This technique has been successful in animals for a while now, but making human embryos this way has been successful only rarely, and then using tissue cells from fetuses or infants.  But the idea is to use cells derived from a patient, who would typically be an adult at the time of the needed treatment, so the current work is a technical advance by virtue of showing that embryos that can be used to give rise to ESCs can be made using cells from adults, even elderly ones.

In this case, the skin cell donors were two men, one age 35, the other age 75.  A total of 126 eggs were obtained from seven women.  The successfully cloned embryos—eight in total—came from using eggs from three of the seven donor women.  A couple of these embryos gave rise to ESCs, depending on the specific cloning procedures used.  The ESCs obtained as a result showed characteristics of true ESCs—including the ability to form tumors (teratomas).  (The potential to form tumors remains a safety issue for any stem cells—ESCs or induced pluripotent stem cells—used as therapy.)

No new ethical issues arise from this report; the well-described issues with cloning all apply.  First, human embryos were created specifically and solely for research, and for destruction in the process.  “Cells” alone were not cloned, but embryos.  The report itself calls them that.  Presumably, these embryos could develop into a full human.  That, the NPR report says, is something that “many people [find]… dangerous and repugnant, [but] it is not broadly illegal.”  Or, maybe the embryos couldn’t develop normally, which would make them, I suppose, severely impaired nascent humans created on purpose for research.  Induced pluripotent cells that do not create new embryos avoid the ethical issue, and might, in the end, be as safe as or safer than ESCs used for treatment.  Some would say “we need to do the experiment,” but if the experiment itself contains unethical features, why should those be carried forward in the experimental design?

And the ESCs created are intended to lead ultimately not just to treatment, but to profit.  The work, performed in South Korea with a government grant from that country, was conceived and executed in part by personnel from the biotech company Advanced Cell Technology.  They would argue, I believe, that the ability to “clone your own” cells for treatment will eventually be beneficial.  But the eggs, of course, are not “your own,” but come, rather inefficiently and potentially riskily (I didn’t see a discussion of the procedure used to induce hyperovulation), from young women “you” may not have heard of.    If ESCs using their cells are commercialized, presumably they retain no financial interest.

I wonder if any of them is named Henrietta…

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