Bioethics @ TIU

Do Extended Pluripotent Stem Cells Raise Ethical Issues?

Posted April 20th, 2017 by Jon Holmlund

On April 6, the journal Cell published work (subscription or online article purchase required) from the Salk Institute in San Diego, in which scientists have created a new “reprogrammed” stem cell.

These cells are called “extended pluripotent stem cells” or “EPS” cells.  They are different from embryonic stem (ES) cells, which are removed from intact embryos that arise from fertilization—typically requiring specific creation and destruction of an embryo.   Of course, ES cells can be human or non-human, depending on the source.

EPS cells are similar to “induced pluripotent stem cells,” or iPSCs, invented in 2006.  The latter are generated from adult skin cells that have been reprogrammed, using genetic alterations.

EPS cells may be made by reprogramming ES cells or skin cells or, if I understand the work correctly, iPSCs.  In this case, the reprogramming is done with a cocktail of chemicals in the lab.

But EPS cells are more capable than iPSCs.  Unlike iPSCs, which can give rise to many different types of cells but not all—including not a placenta and not an entire intact new individual—EPS cells can do all of that.  They are totipotent, meaning they can make all the cells of an individual from their species.  Moreover, they are quite long-lived in the laboratory.  EPS cells from one species—e.g., humans—can be placed into non-human (e.g., mouse) embryos to make hybrid animals that, it appears, survive quite well and can breed.  And, remarkably, the authors of the Cell paper report (again, if I understand correctly, and I think I do) that they were able to use a mouse EPS cell to give rise to a whole new mouse, not “just” a laboratory tissue hybrid.

Upside?  A remarkable, easy source of totipotent cells that appear easy to derive, without requiring production or destruction of embryos, and use in the laboratory, enabling a wide range of research into embryonic development.

The downside?  To read a report in my local paper, the San Diego Union-Tribune, apparently not much.  That paper quotes a couple of stem cell experts, one also a Roman Catholic bioethicist, as saying that EPS cells really don’t pose much of a moral issue.  The other quoted expert says that it would be a “misconstrual” to think this work poses an ethical problem “(i.e., creating whole ‘designer’ organisms from a single cell…).”  These statements are printed a couple of columns after the statement, remarkably breezy in my view: “[The Salk scientists] have even created human EPS cells.  But legal and ethical considerations have prevented them from trying to turn those cells into babies.”

Say what?

It seems that EPS cells are another step toward eventual synthetic organisms.  The Salk scientists successfully, and stably, made mouse-human hybrids by injecting a single human EPS cell into a mouse embryo.  At a minimum, that work would seem to raise similar ethical issues as those raised by animal-human chimeras more broadly.  Indeed, the senior scientist on the recent paper has been working on human-pig hybrids, with growth of human organs, in pigs, for transplantation in eventual view.  “It will be very interesting,” his colleague said, “to test [EPS cells] in the pig.”

And, if mouse EPS cells can be used to give rise to (dare I say “make?”) a whole mouse, what in principle would prevent using human EPS cells to give rise to a baby?  This prospect would seem to invoke ethical concerns substantially similar to those posed by human cloning.  And, because EPS cells can also give rise to non-embryonic tissues, including placenta, needed for reproduction, then ex vivo gestation could be envisioned, although one certainly could not say that it “can’t be far behind.”  There would be rather some distance yet to cover.

So, readers, please set me straight—if this development is indeed not troubling, then what am I missing?  Where am I going wrong?  Or am I raising concerns that “used to be considered germane,” but maybe are not anymore, because we’ve gotten used to the ideas involved…

The comments line is open.

2 Responses

  1. Steve Phillips says:

    I see two main concerns. One is that if these cells truly are able to develop into mature members of their species when given the right environment they are they equivalent of a zygote. That makes human EPS cells human unique human beings at the earliest stage of development who should be considered persons with full moral status. That makes it wrong to destroy them and to experiment on them. It also means that since we would have no way to be assured that they will develop into mature human beings without significant defects creating them would be, like with cloning, creating a class of human beings who we would be obligated to destroy.
    The second concern is that by inserting human EPS cells into embryos of other species we would be creating morally ambiguous organisms that we should not create. There is an inherent goodness in the way that God created life that reproduces within its own kind that we should not violate.

    • Jon Holmlund says:

      This is pretty much how I see it. BTW, the Roman Catholic scientist/ethicist cited in my local paper, and mentioned in the post as saying these cells “do not appear to be embryos” and so don’t seem to pose moral problems was Rev. Tad Pacholczyk from the National Catholic Bioethics Center. I repeat his name only because I note that at this June’s conference of the Center for Bioethics and Human Dignity, one of the scheduled plenary speakers is also from the National Catholic Bioethics center–Dr. Marie Hilliard.

      To my deep regret I can’t be at that conference. Will someone attending please consider asking Dr. Hilliard how it can be that EPS cells pose no particular moral issues, if in fact that is what the Nat’l Catholic Bioethics Center’s position is? I would love to be educated further because I can’t reproduce the logic.

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