Stem-Cell Research Utilizing Embryonic Tissue Should Be Conducted
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Chapter Fifteen Stem-Cell Research Utilizing Embryonic Tissue Should Be Conducted Jane Maienschein Moral claims against human-embryonic stem-cell research are based in a priori claims that include and often start from mistaken assumptions about the natural world. They amount, in effect, to deriving an is from an ought. The result is bad moral arguments, and also bad policy. This chapter looks at what stem cells are, what stem-cell research is, what embryonic stem cells are, why researchers want to do embryonic-stem-cell research, what leads opponents to their poorly informed moral positions, and then why such research should be at least allowed and even why it should be actually conducted. Introduction reasons from claims regarding what ought to be the case to claims regarding what is the case. Centuries of moral philosophers, starting most I argue that in fact there are cases of moral notably with David Hume (1711–1776) in his work, decision-making in which misunderstanding of the A Treatise of Human Nature (Hume, 1739– actual natural world leads to moral errors of this latter 1740/1975), have worried about the relationship sort. This is the case with human-embryonic stem- between what is the case and what we think ought cell research. Here, most of the moral claims against to be the case. The question has been whether it is engaging in this research are based in strong a priori possible to derive an ought from an is, and the answer moral claims that include and perhaps begin from has typically been no. Or at the least, it is accepted mistaken assumptions about the natural world. that what exists in the world is not sufficient to tell Starting with claims linked to bad science (or pseudo- us about what is morally good (Falk, 1976). science or nonscientific claims about nature), the Attempting to do so has been labeled the naturalistic result is bad arguments and, to the extent that these fallacy (initially by philosopher G. E Moore). And moral arguments influence political decisions, bad rejection of this fallacy has led generations of moral policies. This has surely happened with human- theorists to assume that scientific knowledge of the embryonic stem-cell research. empirical world will not allow us to derive moral Let us look at what stem cells are, what stem-cell claims. A mistake in reasoning occurs also when one research is, what embryonic stem cells are, why Copyright © 2013. John Wiley & Sons, Incorporated. All rights reserved. & Sons, Incorporated. © 2013. John Wiley Copyright Contemporary Debates in Bioethics, First Edition. Edited by Arthur L. Caplan and Robert Arp. © 2014 John Wiley & Sons, Inc. Published 2014 by John Wiley & Sons, Inc. Contemporary Debates in Bioethics, edited by Arthur L. Caplan, and Robert Arp, John Wiley & Sons, Incorporated, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/asulib-ebooks/detail.action?docID=1245458. Created from asulib-ebooks on 2018-05-29 13:38:31. researchers want to do embryonic stem-cell research showed that bone-marrow transplants could help in particular, what opponents seem to be thinking leukemia patients or patients who had been exposed that leads them to their poorly informed moral posi- to excessive radiation or for a few other conditions. tions, and then at arguments for why such research This led to the study of what it was that allowed those should be at least allowed and even why it should be particular cells to become blood cells, and it raised actually conducted. questions about how much transplantation of other cells might be possible and to what effect. As often with human experimentation, unless What Are Stem Cells? there is a desperate immediate medical need, we do research in other animals before experimenting with The term stem cell goes back to the late nineteenth humans. Researchers therefore learned a lot about century embryological work of researchers when it mice, and how and why the bone marrow has special was used to refer to those cells that are not yet differ- capacities that other tissues and cells do not have. entiated into the diverse types of cells that come later They also learned much about cell culture from can- (Maienschein, 2003). Stem cells have the capacity to cer cells, including the famous HeLa cells that proved self-replicate and also to give rise to cells that do easy to reproduce and very powerful for a wide become differentiated. Some stem cells are called variety of research questions. Hannah Landecker unipotent, which means that they can become just (2007) has written an important study of such cells one kind of differentiated cell; for example a neural and their history, and Rebecca Skloot (2010) provides stem cell can become only a nerve cell. At least this a wonderful story about the original donor, Henrietta is the case under anything like normal conditions; Lacks. we do not know about all the possible experimental Then, starting in the 1950s biologist Leroy Stevens conditions that might allow different results. Multi- was at the Jackson Laboratories in Maine studying potent stem cells are just like they sound, so that they early developmental stages in mouse cells (Lewis, have the capacity to self-replicate like all stem cells 2000). He discovered a particular strain of mouse— do and also can become differentiated as at least two number 129—that developed differently from different kinds of cells. This is true of hematopoietic normal. Inside the testes in many individuals within stem cells, for example. These are found in the bone this lineage, there emerged a mess of hair, teeth, and marrow and have the capacity to self-replicate and other cells that obviously should not normally arise in also to become any of several different kinds of cells testes. Stevens (1970a, 1970b) set out to understand in the body. Pluripotent stem cells have the capacity to why this strain behaved this way, and in 1970 he self-replicate and can become differentiated as any reported that what he named “pluripotent stem cells” kind of cell. Embryonic stem cells are pluripotent, from the blastocyst stage did not differentiate as they and researchers are now able to induce pluripotency normally would in mice from strain 129. Instead, they in adult somatic stem cells, too. As far as we know, settled in the testes and gave rise to these out-of-place nearly all stem cells that we can actually find in the types of cells. body are these kinds of stem cells: uni, multi, or plu- ripotent stem cells (see the NIH website or any number of textbooks on stem-cell research for defi- What Are Embryonic Stem Cells? nitions and distinctions). The nature of uni- and multipotent stem cells had Other researchers realized the importance of Stevens’s already been well established in humans since the work. By 1981, two groups—Martin J. Evans and 1950s when researchers discovered that hematopoi- Martin H. Kaufman (1981) in Cambridge and Gail etic stem cells in the bone marrow could produce Martin (1981) at the University of California San blood cells after the marrow was transplanted from a Francisco—had succeeded in isolating and culturing donor to a patient. Early cases, in France through the pluripotent cells directly from early embryos. Finally, Copyright © 2013. John Wiley & Sons, Incorporated. All rights reserved. & Sons, Incorporated. © 2013. John Wiley Copyright research of Jean Dausset (1958) and then elsewhere, in 1998, James Thomson and John Gearhart (Thomson 238 Jane Maienschein Contemporary Debates in Bioethics, edited by Arthur L. Caplan, and Robert Arp, John Wiley & Sons, Incorporated, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/asulib-ebooks/detail.action?docID=1245458. Created from asulib-ebooks on 2018-05-29 13:38:31. et al., 1998) demonstrated the same ability to culture formed. At this stage, there is a single layer of cells pluripotent stem cell lines in humans. This step is around the perimeter, and these will give rise to the important because these pluripotent stem cells come placenta later if development progresses (which it from embryos, and unlike the uni- or multipotent often does not). Inside most of the space is a large cells found in the bone marrow, for example, these cavity, yet there is also a cluster of cells that make up embryonic pluripotent cells are not yet differentiated what is called the inner cell mass. These cells are at all. They are not totipotent, meaning that they do completely undifferentiated but have lost their totipo- not have the ability to become the whole body with tency. They are now pluripotent stem cells. And they all its different types. Rather, they have “plural” rather are called embryonic stem cells because they come than “total” potential and are therefore pluripotent. from the embryo. Pluripotent stem cells may also exist in the devel- Normally, then, these embryonic pluripotent stem oping or adult body, but not in large numbers and not cells are neatly packed away inside the blastocyst, in a way that can be isolated and studied. At this time, protected by the surrounding layer of cells that will the only known significant source of many pluripo- eventually make contact with the woman’s uterine wall. tent stem cells is in the embryo. Experimental This blastocyst will in cases of normal development approaches have produced induced pluripotent stem become implanted in the woman’s uterus, and the two cells (or iPS, which involves intervening by adding will begin to grow together. The blastocyst must be specific genes that can cause some adult cells to rediffer- implanted or frozen by no later than 14 days (and often entiate into cells that have some but not all of the earlier), or it will stop cell division and die.