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Advancing Stem Cell Science Without Destroying Human Life
Published January 2007 (Updated April 2007)

Advancing Stem Cell Science Without Destroying Human Life

Link to Full April 2007 PDF Document April 2007 (Updated)
Link to Full January 2007 PDF Document January 2007


Executive Summary

In 2001, President Bush established a policy on stem cell research that promotes scientific progress while respecting ethical boundaries. This policy is based on the President’s firm belief that science and ethics need not be at odds, and that a balance can be struck between the natural desire for rapid scientific progress and the demands of conscience. Drawing careful distinctions between practices that avoid ongoing destruction of nascent human life and those that do not, the President’s policy has allowed stem cell research to advance in rapid and promising ways—as the pages that follow will illustrate—without sacrificing the inherent dignity and matchless value of every human life.

Before President Bush took office, there was no federal funding for human embryonic stem cell research. Then on August 9, 2001, the President announced his decision to allow federal funds to be used for experiments on the embryonic stem cell lines that existed at the date of his announcement. To avoid encouraging further destruction of human embryos, no taxpayer funding could be expended on research using cell lines from embryos destroyed from that point forward.

The President’s policy and new funding has produced considerable scientific investigation and progress. Over the past six years, more than $130 million of federal money has been devoted to human embryonic stem cell research consistent with the President’s policy. Overall, more than $3 billion has gone to innovative research on all forms of stem cells, contributing to dozens of proven medical treatments.

In May of 2005, the President’s Council on Bioethics issued a "White Paper"1 reviewing possible non-destructive sources for additional stem cell lines in the future. Alternative Sources of Human Pluripotent Stem Cells examined the ethical, scientific, and practical prospects for a range of different approaches, and recommended specific investigations that could advance these techniques. The goal of all of these alternative approaches is to produce the functional equivalent of embryonic stem cells, without harming embryos.

In the months since the Council’s report, peer-reviewed studies on each of the approaches have been published in leading scientific journals, suggesting many opportunities for ethical creation of new stem cell lines. One of the most promising possibilities is adult-cell reprogramming. Recent work by two research teams—Kevin Eggan and Chad Cowan of the Harvard Stem Cell Institute, and Shinya Yamanaka and Kazutoshi Takahashi at Japan’s Institute for Frontier Medical—suggests that it may be possible to use chemical and genetic factors to reprogram an adult cell to function like an embryonic stem cell. This approach could prove capable of creating cell lines for the study and treatment of disease without the many ethical dilemmas associated with the creation and destruction of embryos.

In January 2007, another very promising approach was outlined in the journal Nature Biotechnology. Dr. Anthony Atala of the Institute for Regenerative Medicine at Wake Forest University School of Medicine reported2 that he and his colleagues had discovered a new and readily available source of stem cells in the amniotic fluid that cushions babies in the womb.3 While the research is still developing, Dr. Atala and his team believe that these amniotic stem cells may be fully as flexible as embryonic stem cells, while having additional medical advantages: they are easier to grow than human embryonic stem cells, and they do not form tumors (a problem that has plagued embryonic stem cell use)4. And since amniotic stem cells can be collected without destroying human life, they avoid the ethical dilemmas.5

In sum, it increasingly appears that the qualities researchers value in embryonic cells may also exist in other stem cells that are easier to procure, more stable to grow, safer to use in therapies, and free of the ethical violations of embryo destruction. There is a gathering consensus among experts, thanks to technical advances, that today’s heated controversies over research that harms embryos could fade in the future.6

The dramatic advances in stem cell research since 2001 are evidence that the President’s balanced policy is working. Scientists have shown they have the ingenuity and skill to pursue the potential benefits of embryonic stem cell research without endangering nascent human life in the process. In supporting these alternative approaches while maintaining longstanding bioethical guardrails which protect life and dignity, federal science-research funding can stay true to the ideals of a humane society.

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1. Current Federal Law and Policy on Stem Cell Research

The History: From Clinton to Bush

Private-sector human embryonic stem cell research has been and continues to be permissible without restriction in the U.S. The national discussion over embryonic stem cells has largely taken the form of a debate over federal funding of this kind of research. Every year since 1995, the annual HHS appropriations bill has contained language (known as the Dickey-Wicker Amendment) that prohibits federal funding of research in which human embryos are destroyed or subjected to risk of injury or death.7 In 1999 (a year after human embryonic stem cells were first derived in the lab), the Clinton Administration argued that as long as the actual destruction of embryos is performed with private dollars, research on the immediately resulting lines of stem cells could qualify for federal funding, since it technically would not be research in which embryos were directly destroyed with federal funding. That technical reading contradicted the intent of the law, and would have meant that taxpayer dollars would incentivize the destruction of embryos, since knowledge that federal funding would be available once the embryos were destroyed could provide a direct encouragement to engage in that destruction.

The Clinton Administration drafted rules along the lines described above, but their term ended before they could be put into effect. No federal dollars ever went to support human embryonic stem cell research. Upon entering office, President Bush examined the issue closely, seeking a way to advance potentially significant research without using taxpayer funds to support or encourage the destruction of nascent human lives.

On August 9, 2001, President Bush announced his new policy: research on lines of human embryonic stem cells that already existed could qualify for funding, since those lines were created without any taxpayer-funded incentive, and the life-and-death decision on the embryos had already been made. Lines created subsequently would not be eligible, so that federal dollars would not further ongoing embryo destruction. The President’s policy marked the first time the federal government ever made funding available for human embryonic stem cell research.

Embryonic Stem Cell Lines Available for Federal Funding

For more than half a century, the federal government has funded biomedical research through the National Institutes of Health. This support reflects the great value Americans place on the development of treatments and cures for those who suffer afflictions of health. But such support has never been offered indiscriminately or without ethical and moral restrictions. Researchers and institutions that accept federal funds must abide by many ethical strictures, including regulations governing the use of human subjects in research.

Controversies surrounding the morality of certain scientific undertakings have given rise to disputes over federal funding. When making decisions that involve moral and ethical issues plus taxpayer dollars, responsible public policy dictates caution. The debate about whether the federal government should support research that involves the creation or destruction of human embryos naturally falls into this category of policy.

This Administration is the first to provide federal funds for human embryonic stem cell research. And it has established this new funding within a careful framework that avoids encouraging the destruction of human embryos. Scientists can explore potential applications using existing cell lines—21 separate lines have been made available to researchers, in more than 1,000 shipments of cells, with over 3,000 more shipments available upon request from the NIH. To date, over 85 percent of human embryonic stem cell research projects leading to publication worldwide have used these approved lines.8

Chart 1: Federal Funding Devoted to Embryonic Stem Cell Research through NIH. Chart 2: U.S. Federally Approved Lines Used in Global Human Embryonic Stem Research (HESCR)

Non-Federally Funded Embryonic Stem Cell Research

Contrary to common misperceptions, there is no Presidential ban on human embryonic stem cell research. No federal mandates constrain private or state-government funding of any element of this science. In fact, funding by individual states is expected to add up to several billion dollars in the next few years.

The President’s policy has been built on the proposition that stem cell research is proceeding rapidly and will continue to make progress in the future without requiring ethical shortcuts that use taxpayer dollars in ways that tread on established protections for human life. There is no reason to sacrifice longstanding moral concerns in a shortsighted rush for therapeutic payoffs. The wisdom of a careful approach would seem to be underscored by the growing likelihood (based on the last year’s research) that alternative sources of pluripotent stem cells may be available in the future without requiring the embryo destruction that has engendered so much controversy.

Rather than providing taxpayer dollars for methods that raise ethical concerns, the Administration has promoted intensified research into techniques to develop stem cells with the characteristics of those derived from embryos but without doing harm to embryos. And the ethical direction encouraged by the President in 2001 has begun to bear fruit. Scientists are now exploring a range of non-destructive techniques, with numerous articles in leading scientific journals reporting encouraging progress. Some examples are described in the second section of this report.

The Ethical Debate

Our nation has a long history of pioneering medical advances that improve life span and quality. We also have a deep tradition of protecting human life and dignity during scientific investigation.

Research on embryonic stem cells raises profound ethical quandaries. Most fundamentally, is an embryo a human life, and something therefore to be protected? This topic forces us to confront fundamental questions about the beginnings of life and the ends of science. These issues lie at a difficult moral intersection, where the desire to extend and improve life crosses the need to respect all human beings equally.

Embryos are humans in their earliest developmental stage. We do not have to think that human embryos are exactly the same in all ways as older humans to believe that they are entitled to respect and protection. Each of us originated as a single-celled embryo, and from that moment have developed along a continuous biological trajectory throughout our existence. To speak of “an embryo” is to designate a human being at a particular stage.

Our nation was founded on the principle that all of us are created equal, and endowed with a right to exist that is shared fully by all humans. There is no such thing as an excess life. And the fact that a human lacks some particular capacity, or even is going to die, does not justify experimenting on that individual, or exploiting him or her as a natural resource. That has long been the standard in medical ethics—as encoded in the Hippocratic Oath, as well as more modern codes like the Physician’s Oath in the 1948 Declaration of Geneva, which states: “I will maintain the utmost respect for human life from the time of conception.”

To think of other human beings (and especially the weakest and most vulnerable of us at the beginning or end of life) as potential spare parts for use by others is a profound threat to human dignity and our society’s broader respect for its citizens. It is something the U.S. government has scrupulously avoided to this point.

The destruction of embryos for experimental purposes could also open the way to more general and profound manipulations and reengineerings of human life. Without an understanding that life begins at conception, and that an embryo is a nascent human being, there will always be arguments that other uses, takeovers, and makeovers of embryos are justified by potential scientific and medical benefits. Crossing this line would needlessly encourage a conflict between science and ethics that can only do damage to both, and to our nation as a whole.

This potentially dangerous opening would establish exactly the wrong tone as the era of biotechnology dawns. This emerging age has golden promise. But we must pursue its great hope in ways consistent with our principles. That will sometimes require saying no. To find the right paths for medical research, we must be willing to reject paths that are morally wrong.

A policy that defends the inviolability of human life does not preclude the hopeful possibilities of new findings and new therapies. It simply means we must harness the creative powers of our advancing knowledge only to humane and morally balanced means and ends. Amidst today’s dizzying pace of technological innovation, it is worth taking care to make sure that our moral and ethical policies keep up. The biotechnology revolution will bring sound and wholesome human results over the long run only if it is sensibly governed.

The stem cell debate is only the first in what will be an onrushing train of biotechnology challenges in our future. We must establish a constructive precedent here for taking the moral dimensions of these issues seriously. We must make certain we don’t force ourselves into a false choice between science and ethics—because we need both.

And there is good reason, and growing scientific evidence, to believe that we can have both.

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2. Recent Developments in Non-Embryo-Destructive Stem Cell Research and Therapy

In January 2004, the President’s Council on Bioethics published a report entitled "Monitoring Stem Cell Research." In the introduction, the report made the following comment:

Monitoring stem cell research can be a bit like watching Niagara Falls. Not only do scientific reports pour forth daily, as they do in many other areas of research, but a kind of mist rises up from the torrent of news flashes and editorials, making it difficult to separate knowledge from opinion and hope from hype. The underlying biology—whether viewed at the level of the gene, cell, tissue, organ, or organism—is dauntingly complex, as is all cell biology. At any of these levels, in this new and dynamic field, it is frequently difficult for even the most knowledgeable scientist to be truly certain of "what really causes what."9

The emotional appeal of stem cell research places further strains of exaggeration and misinterpretation on scientific claims. The cumulative effect is often a very foggy glass. In the two sections below—on developments in adult stem cell research, and on alternative sources of pluripotent stem cells—we offer a brief overview summarizing some significant recent research. Our aim is to build clearer public and legislative understanding that there are alternative scientific approaches which may be able to produce the functional equivalent of embryonic stem cells, but without harming embryos.

Advances in Adult Stem Cell Research

While research on adult stem cells began decades ago, important new discoveries have been made in just the past few years. Scientists have found adult stem cells in many more tissues than they once thought likely, including the brain, bone marrow, blood, blood vessels, skeletal muscle, skin, liver, and other body parts.10 Given the right conditions, certain kinds of adult stem cells now seem to have the ability to differentiate into a number of different cell types. If this differentiation of adult stem cells can be controlled and sustained in the laboratory, these cells could become the basis of therapies for many serious common diseases and injuries. As examples of potential treatments, an NIH list includes replacing the dopamine-producing cells in the brains of Parkinson's patients, developing insulin-producing cells for type I diabetes, and repairing damaged heart muscle with new cardiac muscle cells following a heart attack.11

Scientists have also reported that adult stem cells may, in some cases, exhibit the ability to form specialized cell types of other tissues, a characteristic known as transdifferentiation, or plasticity. Some experiments have even suggested that certain adult stem cell types may be pluripotent.12 Over the past few years, several examples of adult stem cell plasticity have been reported.13 Most evidence indicates that while embryonic stem cells are capable of becoming all of the cell types of the body, adult stem cells may be more limited. Adult stem cells can also be difficult to isolate, and methods of growing them in culture are still a work in progress.

Adult stem cells, however, do have some important scientific advantages as potential therapies. For one, since adult stem cells can be taken from the patient’s own tissue, they are genetically matched, and would not be rejected by that patient's own immune system. This is one reason they have already been successful in treating many patients, while there are not yet any human clinical trials or successful therapies derived from embryonic stem cells.14 As of April 2, 2007, there have been 1,373 publicly available clinical trials related to adult stem cells, including 671 that are currently recruiting patients.15 Over the last couple of years, clinical trials using adult stem cells have produced encouraging improvements in patients suffering a range of diseases and disorders, including leukemia, lymphoma, diabetes, advanced kidney cancer, and several inherited blood disorders.16

Chart 3: Clinical Trials Related to Adult Stem Cells vs. Embryonic Stem Cells

It is important to note that in comparison to adult stem cell research, embryonic stem cell research is still in its infancy, and its potential should be understood in this context. Human embryonic stem cell studies are in early stages, and are currently being used to help understand the differentiation and functions of many human tissues, including neural, cardiac, vascular, pancreatic, hepatic, and bone. Embryonic stem cells have two properties that make them promising for research and cell therapy. First, they can be grown in tissue culture, and therefore provide an abundant, renewable source of cells. Second, they are pluripotent and can (theoretically) be directed to become virtually any cell type of the adult body.

But while much has been postulated about the ability of embryonic stem cells to generate transplantable cells for medical applications, many scientific hurdles remain before they could be used clinically in the United States. One of the difficulties specific to embryonic stem cells is their propensity to form tumors. This dangerous property is the corollary to their extensive growth potential. Other issues needing solutions include questions of how to generate functional differentiated cells, and how to solve immune rejection issues. Although there is high potential for treatment of degenerative disease with human embryonic stem cells, development of practical applications lags behind adult stem cells, and indeed has been limited to animal studies thus far.17

Advances in Alternative Sources of Pluripotent Cells

Recent biological advances have raised encouraging possibilities for producing powerful stem cells without harming human embryos. What scientists value most about embryonic stem cells is their pluripotency and expandability—that they have the potential to be teased into many, and perhaps all, of the different cell types in the body. But scientists have begun to find that this potential may also exist in certain cells derived without embryos. New ways of producing pluripotent cells that don’t require the destruction (or even endangerment) of human embryos are now being investigated.

In May 2005, the President's Council on Bioethics published Alternative Sources of Human Pluripotent Stem Cells, a White Paper which suggested four possible approaches for alternative sources: (1) by extracting viable cells from embryos already dead; (2) by non-harmful biopsy of living embryos; (3) by extracting cells from artificially created non-embryonic cellular systems or entities (engineered to lack the essential elements of an embryo); (4) by reprogramming (or de-differentiation) of adult cells back to pluripotency. Each of these methods carries its own scientific and ethical uncertainties, but one or more may ultimately offer a path toward an ethically responsible source of pluripotent stem cells.

In January 2007, landmark research from Wake Forest University has suggested yet another alternative: Amniotic fluid, investigators discovered, contains highly flexible stem cells shed by the fetus. These appear to have all the valuable qualities of embryonic stem cells, plus some advantages of their own—like greater ease and speed of culture, and no tendency to produce tumors. Meanwhile, they are comparatively easy to collect without harming human life.

We begin our review with the four methods identified by the Bioethics Council. Just in the short period since they were sketched out in May 2005, significant progress has been made on each of these techniques, as reported in a number of new, peer-reviewed research studies published in leading scientific journals. At this point, one of the most promising avenues appears to be somatic cell reprogramming, which uses chemical and genetic factors to reprogram an adult cell to function like an embryonic stem cell.

Each cell in an individual’s body has the same DNA as every other cell. But in the course of developing into specialized adult tissues, different cells undergo different patterns of gene activation. Somatic cell reprogramming seeks to switch on or off the appropriate genes to transform an adult cell back into the equivalent of an embryonic stem cell. This might be accomplished by stimulating the adult cell with the right combination of chemicals and genes, or by exposing it to the cytoplasm of an existing line of stem cells. This method could, in theory, create stem cells in bulk while bypassing entirely the problem of creating and destroying embryos.

Two research teams that have demonstrated significant progress toward this sort of cell reprogramming are Kevin Eggan and Chad Cowan from the Harvard Stem Cell Institute, and Shinya Yamanaka and Kazutoshi Takahashi from the Department of Stem Cell Biology at Japan’s Institute for Frontier Medical Science. In August of 2005 and August of 2006, respectively, each team published impressive results which seemed to produce pluripotent stem cells by reprogramming ordinary adult cells.

The project18 conducted at the Harvard Stem Cell Institute fused a human adult cell with an embryonic stem cell. (These could come from one of the embryonic stem cell lines that President Bush has approved for use with federal funds.) That effectively turned back the clock on the adult cell such that it was reprogrammed to a pluripotent state. Eggan and Cowan believe that their research could lead to “an alternative route for creating genetically tailored human embryonic stem cells for use in the study and treatment of disease.”19

Drs. Yamanaka and Takahashi published research based on mouse cells.20 Their complex study produced stunningly simple results: They reprogrammed adult cells into a pluripotent state simply by bathing them in four genetic factors. “The finding is an important step in controlling pluripotency, which may eventually allow the creation of pluripotent cells directly from somatic cells of patients,”21 comments Dr. Yamanaka. If successful, this could offer all the benefits of embryonic stem cells and more—these cells could be genetically matched to any prospective patient—without the ethical dilemmas of embryonic destruction.

Other promising avenues are likely to open in the future. The latest alternative, published22 on January 7, 2007, in Nature Biotechnology, involves amniotic-fluid stem cells. Dr. Anthony Atala and a team from the Institute for Regenerative Medicine at Wake Forest University School of Medicine and the Harvard Medical School reported on a new category of readily available stem cells extractable from the waters cushioning babies in utero, as well as the placenta. While this very new research will need to be replicated and confirmed, Dr. Atala and colleagues have already managed to grow useful brain, bone, liver, muscle, and other replacement tissues using these stem cells.23

This discovery suggests that if all U.S. newborns had their amniotic stem cells frozen, they could be available for future tissue replacement without fear of immune rejection. Moreover, a bank of amniotic stem cells from the waters of 100,000 pregnancies could supply 99 percent of the U.S. population with genetically compatible stem cells for possible transplantation. More studies will be needed to confirm that amniotic stem cells can generate all other cell types, but so far every culture attempted has succeeded. It must also be determined that tests conducted in mice will translate to humans.

Meantime, that is but one of several promising glimmers in the latest research. What follows is a summary of the preliminary analysis from the Bioethics Council on the four alternative approaches they discussed in their May 2005 White Paper, supplemented by fresh additional findings from the most significant peer-reviewed studies published in each area since May 2005. It is important to note that while many of these alternative approaches show great promise, all of them are still being tested in animals and are thus in the early stages of development. The Bioethics Council has conducted only a preliminary analysis of the approaches, as used in animals. The Administration does not endorse any of these specific avenues of research in humans at this time. All new approaches will have to be carefully considered by scientists, regulators, and others as appropriate on a case-by-case basis, as further information and research becomes available. It may be that some of these research proposals could prove inconsistent with the Dickey-Wicker Amendment protections against creating, destroying, or harming human embryos, or they may fail some other test of ethical or scientific viability. But the cumulative weight of this emerging science is, as a Washington Post science journalist recently summarized, “adding credence to an emerging consensus among experts that the popular distinction between embryonic and ‘adult’ stem cells…is artificial.”24

a. Pluripotent Stem Cells Derived from Dead Embryos

Under this proposal, viable cells would be derived from early in vitro fertilization (IVF) embryos (of roughly 4-8 cells) that have spontaneously died (as large percentages of early embryos do). Crucial to this approach is defining and verifying what represents organismic death in an early embryo, which represents an ongoing challenge for ethics and science. This would be a determining factor in whether this approach could ever be used in humans. Drs. Donald Landry and Howard Zucker of the Columbia University College of Physicians and Surgeons presented this proposal to the Council.

The preliminary evaluation from the Council in 2005 was that while it raised “some serious ethical questions,” the Council found the proposal “to be ethically acceptable for basic investigation in humans” as long as “stringent guidelines like those proposed by Drs. Landry and Zucker were strictly observed.” At the time, the proposal had not been tested, even in animals. The Council suggested that certain non-invasive studies to explore and define organismic death could be pursued immediately.

In June 2006, Dr. Landry published a peer-reviewed study25 that proposed applying “the ethical framework currently used for obtaining essential organs from deceased persons for transplantation” to the harvesting of stem cells from dead human embryos. The study presented a history of the concept of embryonic death and compared the function of viable embryos with non-viable embryos. Dr. Landry’s research suggested that an irreversible loss of function could be documented and thus used as criteria that would permit a determination of embryonic death. Using this criteria, Dr. Landry made the case that approximately a fifth of all embryos generated for in vitro fertilization could be re-classified as dead. This would enable thousands of new embryonic stem cell lines to be created without destroying a single living embryo.

In September 2006, scientists from the Centre for Stem Cell Biology and Developmental Genetics at the University of Newcastle in Britain published a peer-reviewed study26 that described how embryos lacking essential function could be used as a source for the derivation of human embryonic stem cells.

Despite the promising work of Dr. Landry and the scientists at Newcastle, more work is required to address the concern that stem cells from dead embryos might not have the same pluripotent capacity as stem cells obtained from living embryos. In addition, more research is required on the concept and criteria that would permit determination of embryonic death in a way that is ethically unassailable for use in human embryos.

b. Pluripotent Stem Cells via Blastomere Extraction from Living Embryos

Under this proposal, pluripotent stem cells would be obtained through biopsy of an early human embryo. Crucial to this approach is finding a stage of early embryonic development at which one or a few cells can be removed without harming the embryo, with the removed cells being useable as a source of pluripotent stem cells.

The preliminary evaluation from the Council in 2005 was that this proposal was ethically unacceptable for humans. The Council stated that imposing “risks on living embryos destined to become children, for the sake of acquiring stem cells for research” could not be justified. While the approach could be attempted in animals, the Council did not anticipate that results from animal experimentation could alter its assessment that this method would be ethically unacceptable for humans.

In August 2006, Dr. Robert Lanza and a team at the firm Advanced Cell Technology (ACT) made widely reported27 claims that human embryonic stem cells could be derived from blastomeres without requiring the blastomeres’ destruction. However, once the details of the study’s methodology were reported, it became clear that the techniques used by the researchers did in fact destroy every one of the human embryos used, a fact ACT did not make clear in its initial press releases. This work thus neither proved nor disproved that human embryonic stem cells could be derived from individual cells extracted from an embryo without harming it.

c. Pluripotent Stem Cells Derived from Biological Artifacts

Under this proposal, pluripotent stem cells lines would be derived from an engineered “biological artifact” that lacks the organismal character of a human embryo. Crucial to this approach is demonstrating both that the developing entity is truly not a human embryo and that the cells derived from it are normal human pluripotent cells. In addition, one must show that creating such biological artifacts does not itself introduce other ethical problems. One such proposal, Altered Nuclear Transfer (ANT), was presented to the Council by member Dr. William Hurlbut of Stanford University.

The preliminary evaluation from the Council in 2005 was that this proposal would need to be carefully tested in animals before human trials could be considered, but that there were no insuperable ethical objections that would preclude pursuing it. The possibility of any future endorsement for trying this approach in humans would depend upon a more thorough ethical analysis made possible in part by the animal experiments.

In October 2005, Rudolf Jaenisch and Alex Meissner, scientists at the Whitehead Institute for Biomedical Research at MIT, conducted a peer-reviewed study28 of ANT in mice. “To assess the validity” of ANT, the researchers conducted a study that used a process of gene silencing and nuclear transfer to generate a laboratory-constructed biological entity that could not implant in a uterus and was morphologically unlike a natural embryo. This non-embryonic entity nonetheless yielded fully functional pluripotent stem cells with the same characteristics as those obtained from embryos. The study in mice noted that this approach could produce pluripotent stem cells genetically matched to patients (because the nucleus transferred could be from one of their own cells).

More recently, in November 2006 testimony29 to the Bioethics Council, Dr. Hans Scholer, Director of Cell and Developmental Biology at the Max Planck Institute in Muenster, Germany, discussed further advances that support the scientific feasibility and moral acceptability of ANT. Dr. Scholer used ANT techniques to preemptively silence a key factor essential for defining an embryonic organism. Using this technique he was able to obtain pluripotent stem cell lines at an earlier stage and at a rate 50 percent higher than from direct destruction of IVF-created embryos.

d. Pluripotent Stem Cells via Somatic Cell De-differentiation

Under this proposal, adult cells would be reprogrammed to “de-differentiate” back into pluripotent stem cells. Crucial to this approach is discovering a way to reverse cell differentiation all the way to pluripotency, but without creating an organism capable of developing as nascent life.

The preliminary evaluation from the Council in 2005 was that this approach was ethically acceptable for use in humans, if and when it becomes scientifically practical, provided the line between pluripotent cell and living organism can be maintained. The Council noted that while this approach was scientifically and technically uncertain, there were encouraging results appearing in the scientific literature.30

In 2005, scientists from the Harvard Stem Cell Institute published a peer-reviewed study31 in which a fusion of human embryonic stem cells with adult cells suggested that adult cells could be reprogrammed. If the remaining technical barriers are overcome—and some of them are significant—the approaches discussed in this study could circumvent societal concerns over cloning or the destruction of human embryos. A year later, Drs. Takahashi and Yamanaka of Japan published their peer-reviewed mouse study32 examining 24 genes as candidates for conveying pluripotency.33 They discovered that altering just four genetic factors proved sufficient to change adult cells into pluripotent stem cells. Scientists will now try to determine if human adult cells can be similarly reprogrammed using this method.

In November 2006, scientists from the School of Biosciences and Institute of Genetics, University of Nottingham, Loughborough, reviewed34 the recent scientific advancements in reprogramming and concluded there is sufficient evidence demonstrating that adult cells can be reprogrammed and that cell-based approaches for therapeutics may be a realistic expectation in the future. The study reviewed nine reprogramming approaches that are commonly used today and commented on their respective advantages and limitations. While it is too early to tell which approaches may or may not work, the sheer number of methods makes clear that there may be several different ways to induce reprogramming of adult cells in the future.

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As this report shows, there has been tremendous scientific progress of late in exploring methods of deriving pluripotent stem cells without destroying embryos. This groundbreaking alternative research has developed under President Bush’s insistence on advancing stem cell research within clear ethical guidelines. With continued support for non-destructive alternatives, new developments will continue to unfold in this field in the years to come, holding the potential for innovative progress toward new medical cures, while at the same time upholding human dignity and the sanctity of innocent life.

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1 President’s Council of Bioethics, White Paper: Alternative Sources of Human Pluripotent Stem Cells, May 2005. (

2 Atala, A et al., Isolation of amniotic stem cell lines with potential for therapy, Nat Biotechnology. 2007 Jan 7; [Epub ahead of print].

3 Mary Carmichael, New Stem-Cell Source Could Alter Debate,, January, 7, 2007.

4 Mary Carmichael, New Stem-Cell Source Could Alter Debate, Newsweek, Web Exclusive, January 8, 2007; Maggie Fox, Human stem cells found in amniotic fluid, Reuters, January 8, 2007; Breakthrough To Report In Stem Cell Research, The Discovery Of A New Source Of Stem Cells, NBC's Nightly News, January 7, 2007; Dan Harris, These Cells Can Be Gathered Without Hurting The Mother Or The Fetus, And Would Prove Much Less Controversial Than Research Done With Embryos,”ABC's World News Sunday, January 7, 2007.

5 Dan Harris, These Cells Can Be Gathered Without Hurting The Mother Or The Fetus, And Would Prove Much Less Controversial Than Research Done With Embryos, ABC's World News Sunday, January 7, 2007.

6 Rick Weiss, Scientists See Potential in Amniotic Stem Cells, Washington Post, January 8, 2007; Rick Weiss, Stem Cell Advances May Make Moral Issues Moot, Washington Post , June 6, 2005.

7 The full text of the Dickey Amendment can be found in each year’s Labor/HHS Appropriations Bill. The law states that “None of the funds made available in this Act may be used for—(1) the creation of a human embryo or embryos for research purposes; or(2) research in which a human embryo or embryos are destroyed, discarded, or knowingly subjected to risk of injury or death greater than that allowed for research on fetuses in utero under 45 CFR 46.204 and 46.207, and subsection 498(b) of the Public Health Service Act (42 U.S.C. 289g(b)). (b) For purposes of this section, the term ‘human embryo or embryos’ includes any organism, not protected as a human subject under 45 CFR 46 as of the date of the enactment of the governing appropriations act, that is derived by fertilization, parthenogenesis, cloning, or any other means from one or more human gametes or human diploid cells.”

8 Jason Woen-Smith and Jennifer McCormick, An International gap in Human ES Cell Research, Nature Biotechnology, 2006 Apr;24(4):391-2

9 President’s Council of Bioethics, Monitoring Stem Cell Research, January 2004, Pg. 15 (








17 (Pg. 8)

18 Cowan, C.A., Eggan, Kevin, et al., Nuclear reprogramming of somatic cells after fusion with human embryonic stem cells, Science, 2005 Aug 26;309(5739):1369-73.

19 Cowan, C.A., Eggan, Kevin, et al., Nuclear reprogramming of somatic cells after fusion with human embryonic stem cells, Science, 2005 Aug 26;309(5739):1369-73.

20 Takahashi, K. and S. Yamanaka, Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors, Cell, 2006 Aug 25;126(4):663-76. Epub 2006 Aug 10.


22 Atala, A et al., Isolation of amniotic stem cell lines with potential for therapy, Nat Biotechnology. 2007 Jan 7; [Epub ahead of print].


24 Rick Weiss, Scientists See Potential in Amniotic Stem Cells, Washington Post, January 8, 2007.

25 Don Landry et al., Hypocellularity and Absence of Compaction as Criteria for Embryo Death, Regenerative Medicine. Published in June 2006.

26 Zhang, X., P. Stojkovic, et al., Derivation of human embryonic stem cells from developing and arrested embryos, Stem Cells Express, 2006 Dec;24(12):2669-76. Epub 2006 Sep 21.

27 Klimanskya, I., Y. Chung, S. Becker, et al., Human embryonic stem cell lines derived from single blastomeres, Nature, Advance online publication, August 23, 2006.

28 Meissner, A. and R. Jaenisch, Generation of nuclear transfer-derived pluripotent ES cells from cloned Cdx2-deficient blastocyst, Nature, 239: 212-5 (2006).

29 President's Council on Bioethics, Transcript from November 16, 2006. (

30 Guan K et al., Pluripotency of spermatogonial stem cells from adult mouse testis, Nature 440, 1199-1203, 27 April 2006; Kanatsu-Shinohara M & Shinohara T, The germ of pluripotency, Nature Biotechnology 24, 663-664, June 2006; Cyranoski D, Stem cells from testes: could it work? Nature 440, 586-587, March 30, 2006; Carlin R et al., Reproductive Biology and Endocrinology 4:8, doi:10.1186/1477-7827-4-8, 6 February 2006.

31 Cowan, C.A., Eggan, Kevin, et al., Nuclear reprogramming of somatic cells after fusion with human embryonic stem cells, Science, 309: 1369-1373, 2005 Aug 26;309(5739):1369-73.

32 Takahashi, K. and S. Yamanaka, Induction of Pluripotent Stem Cells from Mouse Embryonic and Adult Fibroblast Cultures by Defined Factors, Cell, 2006 Aug 25;126(4):663-76. Epub 2006 Aug 10.


34 Andrew Johnson et al., Reprogramming Somatic Cells into Stem Cells, Reproduction, November 2006.

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Appendix 1: Embryo Adoption as an Alternative to Embryo Destruction

In the complex debate over human embryonic stem cell research, it is important to remember that real lives are involved—both the lives of those with diseases who might find therapies or cures from this research, and the lives of embryos who will be destroyed or harmed in the process.

President Bush strongly supports embryo adoption as a life-affirming alternative to embryo destruction. Embryo adoption provides an option for the survival and development of embryos frozen in fertility clinics, giving them a chance at life and giving infertile couples the opportunity to build a family.

The value in frozen embryos can be seen in each child who began his or her life as a product of in vitro fertilization, remained unused and frozen after the fertility treatments were complete, but now breathes and burgeons in an adopted family. These “snowflake” children remind us of what is lost when embryos are destroyed in the name of research. They remind us that all human life begins as but a tiny collection of cells. And, they remind us that in our zeal for new treatments and cures it is important for society not to abandon moral fundamentals.

Embryo adoption shows that frozen embryos do not have to be destroyed. The Administration has worked to inform doctors and infertile couples of embryo adoption programs, and the President signed a bill in 2002 granting $1 million per year for HHS grants to publicize embryo adoption opportunities. To date, the Nightlight Christian Adoptions agency has matched 289 placing families with 192 adopting families. The resulting new lives are not raw materials to be exploited, but rather gifts to be cherished.

Embryo adoptions programs have led to the birth of 118 babies, with 25 families currently expecting. These children are reminders that embryos are not raw materials to be exploited, but rather gifts to be cherished.

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Appendix 2: What is the Connection to Human Cloning?

Human cloning would involve creating a new human being who is genetically identical to an existing human. It would be done by replacing the nucleus of an egg with the nucleus of a cell taken from the body of a donor. The result would be a developing human embryo carrying the genetic identity of the nucleus donor. This is the same technique that was used to create Dolly the sheep.

A cloned embryo is produced in the lab, and so exists at first outside the body of a mother, like an IVF embryo. The question of what is done with that embryo is the same as what is done with IVF embryos. It could be implanted in a woman, to potentially produce a cloned child. Or it could be experimented on or destroyed for its stem cells. Neither of these options is morally acceptable. We do not want to produce cloned children, for a wide variety of ethical reasons with which nearly everyone agrees. Likewise, we should not create human life merely to use it for research. As the President has said, “We recoil at the idea of growing human beings for spare body parts, or creating life for our convenience.”

Since neither possible use of cloned embryos is morally acceptable, the President has consistently argued that the only appropriate, effective, and responsible policy toward human cloning is to prohibit it. To prevent either the creation of life for experimental destruction or the production of cloned children, he believes, cloned human embryos should never be created.

Advocates of cloning for research (often referred to by its technical name—somatic cell nuclear transfer, or SCNT) try to assuage concerns by assuring us that they do not plan to transfer the cloned embryos into the womb of a woman. But whether or not the embryo is implanted in a woman for gestation and birth is not the action that defines human cloning, and makes it repugnant to most observers. That is simply a transfer, something accomplished with IVF embryos routinely. The morally significant act in human cloning occurs before the transfer—at the point when the embryo is manufactured. Intentionally creating human life to destroy it for laboratory research is itself a violation of an important moral principle. Moreover, the development of the cloning techniques involved will inevitably hasten the day when some practitioner oblivious to public recoil will arrange for embryos to be implanted, and cloned humans to be born.

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Appendix 3:

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