Stem cells and cloning: The fuss, revisited


  • The views here expressed are solely those of the author and are not meant to reflect the policy of either Wiley-Liss, Inc. or The American Association of Anatomists.

A news story called out to me from the front page of The Washington Post recently: “Human Fat May Provide Stem Cells” (Weiss, 2001b). The story described work by Marc Hedrick of the UCLA School of Medicine, Adam Katz of the University of Pittsburgh School of Medicine, and their colleagues. The researchers, who studied discarded adipose tissue from liposuction procedures, found pluripotent stem cells that could be coaxed into developmental pathways resulting in cartilage, muscle, and bone cells (Zuk et al., 2001).

Less than a decade ago, bone marrow donation seemed the only source of potentially life-saving regenerative cells, and, at that, only in the context of restoring a recipient's immune and hematopoietic systems. This novel revelation regarding adipose tissue is just the latest in an unquenchable spate of reports detailing discovery of adult stem cells derived from tissues never before thought to contain them. The reports are exciting because of the prospects for utilizing easily accessible adult stem cells in clinical research for treatment of debilitating human disease.

This latest story is particularly notable for being the third reported case of a tissue, arguably definable as “waste tissue,” shown to possess stem cells; in this third case, adult stem cells. To wit, adipose tissue, whether considered a health risk or a cosmetically alterable trait, carries none of the extreme legal, ethical, and emotional baggage borne by the other two cases of “waste tissues”: namely, human fetal and embryonic tissue.

While no one would seriously challenge the ethics of medical experimentation with fat. However, moral and ethical opposition to studying human fetal and embryonic stem (ES) cells has translated into a moratorium on federally funded research in the United States in these areas. Intense efforts to develop a legal and ethical framework for such research are ongoing worldwide but still fall short of real progress (Anonymous, 2001).

Let the ongoing fuss over cloning and stem cells be diffused by considerate citizen-scientists such as yourselves, who step down from your ivory towers to educate, and thereby empower, the nonscientific public.

Researchers, regardless of their religious or moral beliefs, will undoubtedly embrace the finding by Zuk et al. (2001) of pluripotent stem cells in adipose tissue with eager (if cautious) anticipation. However, research on human and nonhuman fetal/embryonic tissue will continue to populate the literature for the foreseeable future despite the U.S. funding moratorium. To be sure, reports of advances in ES cell technologies such as those cited in this issue's feature article by Gokhan and Mehler (2001) describe compelling experiments leading to potential ES cell therapies for debilitating neurodegenerative conditions like Alzheimer and Parkinson diseases. There is also open debate within the research community regarding the semantic and biologic definitions of stem cells, as discussed by Geuna et al. (2001) in this issue. Both articles reveal that the energetic discussion over what stem cells are, and what they can do, is far from over—and never unenlightening.

Contrast this intellectual enthusiasm (coupled with some ethical and legal implications) with the gloom that is befalling the field of animal cloning. Just as we are basking in the glow of promise that comes with each new report of adult human stem cells, more reports of problems with animal cloning appear in the scientific and popular literature. How the excitement over animal cloning has dimmed since that first report of Dolly the Sheep (Wilmut et al., 1997) just a few years ago!

Jaenisch and Wilmut (2001), two pioneers of the field, now estimate a failure rate of cloning experiments that approaches 99%. A growing number of problems are being reported in animal cloning cases—alarming problems not only with the developing clone but also with the surrogate mother that can jeopardize the survival of both (Weiss, 2001a). To read of a newborn cloned lamb that started spontaneously hyperventilating due to dysmorphology of its pulmonary arteries, or of surrogate mother cows dangerously swollen with fluid during gestation of a cloned bovine fetus, is disheartening at the very least (Weiss, 2001a). It is not clear whether Dolly, the paradigm for nuclear transplantation cloning, is in fact “normal.”

Even more alarming are the widely publicized efforts of late by two obscure and controversial researchers— P. Zavos in the United States and S. Antinori in Italy—to clone a human being (Jaenisch and Wilmut, 2001; Weiss, 2001a). Never mind that the public is barely grasping the fact that cloning a dead loved one, even if possible, would in no way “bring back” the same daughter, son, or old Uncle Pete. The frighteningly high failure rate for mammalian cloning reflects the potential for myriad malformations at every developmental stage, from failure of proper epigenetic reprogramming before the first nuclear division to neonatal developmental failure, not to mention potentially lethal malformations of the placenta during gestation (Jaenisch and Wilmut, 2001).

What subtle yet catastrophic malformations in the complex physiologic systems of humans could result from attempted cloning? What ethical researcher could honestly state that a one in 100 chance of producing a viable human clone would be worth the risk that even one of the 99 “failures” might be self-aware enough at birth to suffer? What ethical fertility expert would concede to testing a procedure in humans in which there is growing evidence in animals that it poses serious risk to the health of the surrogate birth mother? This should be an untenable risk to face in our civilized, if not litigious, society.

The answer to the human cloning question—Just Say NO!—seems a no-brainer, perhaps easier than the answer to the question of using human fetal or embryonic tissue as a source of pluripotent stem cells for clinical benefit. Indeed, Great Britain will soon be the first country in the world to ban human cloning (Waugh, 2001).

As stated previously in the editorial by Carlson (1999), the technical and ethical differences between human stem cell research and human cloning research are vast. As I reinforce here, the fundamental ethical issues for the two—though they may derive from similar origins—are arguably very different. It must be our charge as activist scientists to educate a science-wary public accordingly.

It could be as simple as this: if you catch an error in an article in your local paper using “stem cell” or “cloning” inappropriately, call them on it. Columnist George F. Will managed to conflate “gene therapy” and “cloning” earlier this year (Will, 2001) and so I gently took him to task in a letter to the editor. (Alas, my letter remains unpublished.) More engaging efforts might include gently steering a misinformed cocktail conversation toward scientifically sound premises, from which a more appropriate picture of the relevant ethical issues could be painted. We are not all trained as ethicists, but we all are trained as biologists, and many of us are trained as teachers.

Let the ongoing fuss over cloning and stem cells be diffused by considerate citizen-scientists such as yourselves, who step down from your ivory towers to educate, and thereby empower, the nonscientific public. Such efforts would go a long way toward helping to dispel inappropriate bioethical specters roused by a confusing scientific lexicon that describes a new and promising application for stem cells every week, or by researchers of dubious intentions who claim the need to clone humans in the name of advancing fertility research. Otherwise, all biologists risk losing much in the way of public trust and federal funding down the road.