Dr. James Thomson and his colleagues at the University of Wisconsin at Madison are once again in the news as they announce in their latest publication in the journal Science that they have created human iPS (induced pluripotent stem) cells without the use of some of the dangerous reprogramming methods by which such cells were created in the past.

First derived from the skin of mice, then from the skin of humans, and most recently from the blood of humans, iPS cells are generated from ordinary adult somatic (non-stem cell) cells and therefore circumvent the ethical controversies that surround embryonic stem cell research, since iPS cells are not derived from embryos. Ethics and politics aside, however, iPS cells still have a long way to go before they can be incorporated into clinical therapies, since the laboratory methods by which iPS cells are derived pose too many medical dangers for any potential patient. Not only are (cancer-causing) oncogenes used as cellular reprogramming agents, but dangerous retroviruses have also typically been used as delivery agents that carry the reprogramming genes into the cell. Now, however, scientists may have found an alternative, at least to the retroviral delivery methods.

In a paper entitled “Human Induced Pluripotent Stem Cells Free of Vector and Transgene Sequences”, Dr. Thomson and his colleagues describe how they used “non-integrating episomal vectors” instead of retroviruses to derive human iPS cells. As they further explain, “Human iPS cell derivation previously required vectors that integrate into the genome, which can create mutations and limit the utility of the cells in both research and clinical applications.” Such integrating “vectors” have typically consisted of retroviruses or their lentiviral subset, which have been used as vehicles of gene delivery since the 1970s. The principle exploits the highly evolved molecular capability of viruses by which they infect cells, and through which transportation of their own viral genome into the host cell occurs. Also known as transduction, the process is a commonly used tool throughout molecular biology and genetics, especially in the field of gene therapy. The disadvantage, of course, is that the use of a live virus is not without risks, and while such risks may be modified to some extent for laboratory research, the risks can never be fully eliminated which therefore disqualifies such methods for use in any human clinical therapy.

Episomes, also known as plasmids, which are usually double-stranded circular molecules and can either exist independently of, or integrated with, the chromosome, can also be used as “vectors” to deliver genes inside of cells. In contrast to retroviruses and lentiviruses, the non-integrating episomal vectors that Dr. Thomson and his colleagues chose, which consist of “circles of DNA” plasmid vectors, will eventually vanish from the host cells over time, leaving no trace of their presence or activity other than the delivery of the desired genes into the cells.

As Dr. Thomson explains, “That means they [the iPS cells] are less likely to form tumors, less likely to destroy the function of some important gene.” According to Dr. Jeremy Berg, director of the National Institute of General Medical Sciences at the National Institutes of Health, “What Dr. Thomson has done for the first time in human iPS cells is create methods which don’t involve inserting DNA into the host genome at all – using plasmids which go into the cells but never get incorporated into the DNA.”

In their study, Dr. Thomson and his colleagues used a number of genes which included OCT4, SOX2, NANOG, LIN28, c-Myc and KLF4, all of which are transcription factors involved in cellular self-renewal and differentiation except for LIN28 which is a marker of undifferentiated human embryonic stem cells, and c-Myc which is a gene involved in protein-coding, a mutated version of which is known to be oncogenic (in other words, it can cause cancer) and in fact the entire Myc family of genes are known as proto-oncogenes and are implicated in some types of cancer when mutated or overexpressed. As the authors noted, transgene linkage and the addition of KLF4 and c-Myc improved reprogramming efficiency; nevertheless, the continued use of the c-Myc oncogene still poses a risk of cancer and therefore the overall method is still in need of further “refinement” before it can be translated into a human clinical therapy.

For the construction of expression vectors, the authors describe how “Transgenes were cloned into a modified lentiviral vector or the oriP/EBNA1-based pCEP episomal vector (Invitrogen) for reprogramming”, and human fibroblasts were thereby transduced. Additionally the authors elucidate the mechanisms by which combinations of episomal plasmids were co-transfected into fibroblasts via nucleofection for reprogramming with oriP/EBNA1-based episomal vectors. As Dr. Thomson and his colleagues further describe, “After removal of the episome, iPS cells completely free of vector and transgene sequences are derived that are similar to human embryonic stem cells in proliferative and developmental potential.” Indeed, the new iPS cells also resemble human embryonic stem cells in their ability to form teratomas (tumors), and in fact one section of the paper which addresses this fact is specifically entitled “Teratoma formation”, in which the authors confirm that the episomal-vector-generated human iPS cells were injected into the hind limb muscles of 6-week-old immunocompromised SCID-beige mice, from which, “After five to ten weeks, teratomas were dissected and fixed in 4% paraformaldehyde. Samples were embedded in paraffin and processed with hematoxylin and eosin staining at the Histology Lab at the School of Veterinary Medicine, University of Wisconsin-Madison, WI.”

Technically speaking, iPS cells are not stem cells but, as the name implies, they are cells which have been artifically “induced” to exhibit pluripotency. As such, iPS cells resemble embryonic stem cells in their ability to differentiate, at least hypothetically, into all 220 types of tissue that exist throughout the human body – although in actuality nobody has ever differentiated any type of cell into all the various types of human body tissue. Nevertheless, despite the fact that iPS cells can be created without the need for embryos, iPS cells are still plagued by many of the problems that are inherent in embryonic stem cells, not the least of which is the risk of teratoma (tumor) formation, which is characteristic of all pluripotent cells since teratoma formation is part of the official scientific definition of pluripotency. Exactly how the strong, natural tendency toward teratoma formation could be “turned off” in any pluripotent cell with any certainty remains merely one of many scientific problems associated with pluripotent cells that have yet to be resolved. By sharp contrast, adult stem cells do not pose such problems since adult stem cells are not pluripotent and therefore are not able to form teratomas. Not surprisingly, therefore, adult stem cells are already being used in clinics around the world as therapies for a wide variety of diseases and injuries, whereas any type of pluripotent cell – whether of embryonic or iPS origin – will require at least another decade of research, if not more, before it could be available in the form of a clinical therapy.

Precisely for such reasons, Dr. Thomson is among the first to point out that the most immediate uses for iPS cells will not be as clinical therapies but instead will most likely be in the field of drug testing and development, which previously had been conducted on laboratory animals, not on humans nor on human tissue. As the authors state at the very beginning of their paper, iPS cell technology “has applications in basic biology, drug development, and transplantation”, but the words “clinical therapy” are conspicuous by their absence since such words do not appear in the short list of applications of iPS cells, at least not for the immediate future. Until their multiple inherent medical dangers, only one of which is the formation of teratomas, can somehow be eliminated, iPS cells are not, and will not be, ready for the clinic. Even though Dr. Thomson and his colleagues have solved the problem posed by the previous use of retroviral vectors, their continued use of the c-Myc oncogene, which “improved reprogramming efficiency”, still poses a risk of cancer and therefore a safer substitute for this oncogene must be found before iPS cells can be translated into a human clinical therapy.

As the authors conclude, “These results demonstrate that reprogramming human somatic cells does not require genomic integration or the continued presence of exogenous reprogramming factors, and removes one obstacle to the clinical application of human iPS cells.”

Even though “one obstacle” has been removed, several more still remain.

The paper was first published online by Science Express, which provides the electronic publication of selected papers from the journal Science in advance of print. Both Science and Science Express are publications of the American Association for the Advancement of Science (AAAS), which was founded in 1848 and serves approximately 10 million individuals worldwide through 262 affiliated societies and scientific academies. According to their website, the journal Science “has the largest paid circulation of any peer-reviewed general science journal in the world, with an estimated total readership of one million.”

Created by Executive Order under President George W. Bush in November of 2001, the President’s Council on Bioethics exists “to advise the President on bioethical issues that may emerge as a consequence of advances in biomedical science and technology.” Today, the Council issued a letter coauthored by 10 of the Council’s 18 members, in which the authors of the letter formally state their objections to President Obama’s new policy on stem cell research. Additionally, an eleventh member, the Chairman of the Council, also issued a formal statement in which he declared that he supports the objections of the 10 Council members.

As stated on its website, www.bioethics.gov, and in regard to its advisory role, the mission of the President’s Council on Bioethics includes the following objectives: 1/ to undertake fundamental inquiry into the human and moral significance of developments in biomedical and behavioral science and technology, 2/ to explore specific ethical and policy questions related to these developments, 3/ to provide a forum for a national discussion of bioethical issues, 4/ to facilitate a greater understanding of bioethical issues, and 5/ to explore possibilities for useful international collaboration on bioethical issues.

In this capacity, the Council points out that, “To advance human good and avoid harm, biotechnology must be used within ethical constraints. It is the task of bioethics to help society develop those constraints, and bioethics, therefore, must be of concern to all of us.” The Council thus not only addresses topics that are related to stem cell research and therapies but also topics that pertain to healthcare in general, including genetics, organ transplantation, nanotechnology and end-of-life issues, among other rapidly changing medical fields.

The current 18 Council members are listed herein (an asterisk denotes a member who participated in the formal letter of objection): 1/ Edmund D. Pelligrino, M.D.*, Chairman of the Council, Professor Emeritus of Medicine and Medical Ethics, and Adjunct Professor of Philosophy at Georgetown University, 2/ Floyd E. Bloom, M.D., The Scripps Research Institute, 3/ Benjamin S. Carson, M.D.*, Johns Hopkins Medical Institutions, 4/ Rebecca S. Dresser, J.D., M.S., Washington University, 5/ Nicholas N. Eberstadt. Ph.D.*, American Enterprise Institute, 6/ Jean Bethke Elshtain, Ph.D.*, University of Chicago, 7/ Daniel W. Foster, M.D., University of Texas, Southwestern Medical School, 8/ Michael S. Gazzaniga, Ph.D., Dartmouth College, 9/ Robert P. George, J.D., D.Phil, Princeton University, 10/ Alfonso Gomez-Lobo, Dr. Phil.*, Georgetown University, 11/ William B. Hurlbut, M.D.*, Stanford University, 12/ Donald W. Landry, M.D., Ph.D.*, Columbia University, 13/ Peter A. Lawler, Ph.D.*, Berry College, 14/ Paul McHugh, M.D.*, Johns Hopkins Hospital, 15/ Gilbert C. Meilaender, Ph.D.*, Valparaiso University, 16/ Janet D. Rowley, M.D., The University of Chicago, 17/ Diana J. Schaub, Ph.D.*, Loyola College, and 18/ Carl E. Schneider, J.D., University of Michigan.

Among other issues, the 11 objecting Council members raise 3 primary objections, namely, 1/ contrary to Obama’s highly publicized remarks, President Bush never banned embryonic stem cell research, 2/ alternative, safer and ethically noncontroversial methods of deriving pluripotent stem cells have eclipsed embryonic research, and 3/ Obama has now opened the door to human cloning which is a slippery slope that leads inevitably to gravely serious scientific as well as ethical problems.

On March 9th of this year, President Obama removed some, though not all, restrictions on the use of federal funds for research on embryonic stem cells. (Please see the related news articles on this website, entitled “A High-Profile Proponent of Embryonic Stem Cell Research Sharply Criticizes Obama’s Policy”, dated March 13, 2009; “Obama Signs Law Restricting Federal Funding of Embryonic Stem Cell Research”, dated March 11, 2009; “Obama Rescinds Bush-Era Executive Order Pushing for More Ethical Stem Cell Research”, dated March 10, 2009; “Obama Decrees Changes in Embryonic Stem Cell Research, Though Not What One Might Expect”, dated March 9, 2009; and “Former Director of N.I.H. Explains Why Embryonic Stem Cells are Obsolete”, dated March 4, 2009).

Today’s letter from the President’s Council on Bioethics clarifies Obama’s actions by framing those actions within “the context of work the Council has done over the past seven years.” Among other things, the letter states: “At the outset of his remarks, the President characterized his action as ‘lift[ing] the ban on federal funding for promising embryonic stem cell research.’ That language does not accurately characterize the federal funding policy that has been in place during the entire tenure of this Council. The policy announced by President Bush on August 9, 2001, did not BAN federal funding of embryonic stem cell research; rather, for the first time, it provided and endorsed such funding (as long as the stem cell lines had been derived prior to that date). The aim of this policy was not to shackle scientific research but to find a way to reconcile the need for research with the moral concerns people have. That is precisely how the Council formulated the question in ‘Monitoring Stem Cell Research: How can embryonic stem cell research, conducted in accordance with basic research ethics, be maximally aided within the bounds of the principle that nascent human life should not be destroyed for research?’ Attention to the ethical principles that ought to guide and limit scientific research has been constant since the end of World War II. Different kinds of research have been limited, and sometimes prohibited, not in order to suppress science but in order to free it as a genuinely human and moral activity.”

Indeed, as any scientist who has ever worked on a “classified” government contract knows, some areas of scientific research are so important – and potentially so dangerous – that access to such research is carefully restricted only to those scientists who pass stringent qualification standards. The “Manhattan Project” of World War II was perhaps the most extreme example, during which physicists in the United States developed the world’s first atomic bomb – but many subsequent examples also exist, usually within the realm of physics and engineering, and around which the entire military-industrial complex has evolved, through which scientists serve the interests of the U.S. Department of Defense. The U.S. is hardly alone in this type of classification system, which exists in most industrialized countries and usually pertains to ways in which science and technology can be applied to national defense. Now, however, for the first time in human history, new and powerful technologies exist at the intersection of medicine and molecular engineering which, in benevolent hands, hold great potential to heal; but in deliberately malevolent or merely in ignorant or accidental hands the same technologies can cause great harm. The name of this double-edged sword, of course, is stem cell research. As the Pulitzer Prize-winning columnist and former Presidential Science Advisor, Dr. Charles Krauthammer, pointed out in his Washington Post op-ed article last month, “Given the protean power of embryonic manipulation, the temptation it presents to science and the well-recorded propensity for evil even in the pursuit of good, lines must be drawn.” (For a more detailed review of Dr. Krauthammer’s criticism of Obama’s new stem cell policy, please see the related news article on this website, entitled, “A High-Profile Proponent of Embryonic Stem Cell Research Sharply Criticizes Obama’s Policy”, dated March 13, 2009). Certainly no government leaders of any nation would seriously entertain the idea of allowing their own physicists to conduct nuclear weapons experimentation without some guidelines, and even in biological and chemical laboratory research that is unrelated to stem cells, there are still formal guidelines that must be followed, at the very least to protect the safety of the researchers. Similarly, outside of medicine, in many other branches of science, such as with the growing concern over ecological and environmental consequences of combustible fuel, a strong sense of ethics is encouraged and applauded, and formal laws and regulations exist in an effort to protect the environment and its inhabitants. Likewise, even outside the realm of science, such as with the recent global economic crisis, there is a loud outcry for serious legal and ethical reform requiring transparency, responsibility, accountability and oversight, both at the corporate and at the individual levels, and precisely for these reasons rules and regulations exist to govern the financial industry. Similarly, the idea that embryonic stem cell research might be free to proceed without any guidelines whatsoever would be equally as nonsensical as allowing the testing of nuclear weapons to be conducted without rules and regulations, or allowing industrial pollutants to be discharged into the environment without rules and regulations, or allowing stock markets and banks and other financial systems to conduct business without rules and regulations. In fact, in 2005 the National Academy of Sciences first released a publication entitled “Guidelines for Human Embryonic Stem Cell Research”, which in turn was updated in 2007 and 2008, and no doubt will continue to be updated throughout the future. But thus far, such guidelines are only that, namely, guidelines, and scientists are free to ignore such recommendations if they choose to do so. It is perhaps historically noteworthy to observe that the presidential need for scientific advice is nothing new or modern, since the National Academy of Sciences (NAS) was in fact formed by Congressional Charter in 1863 under President Abraham Lincoln who not only created the NAS but who also personally appointed the first 50 charter members. Today, together with the National Academy of Engineering (NAE), the National Research Council (NRC) and the Institute of Medicine (IOM), the NAS comprises the famed “National Academies” which have as their mission the increasingly serious responsibility to serve as “advisors to the nation on science, engineering and medicine.” As with N.I.H. (the National Institutes of Health), however, the National Academies are not charged with the specific task of addressing matters of bioethics. That task has been assigned to the President’s Council on Bioethics, the advice of which, thus far, President Obama has chosen to ignore.

In regard to President Obama’s new stem cell policy and exactly how it differs from President George W. Bush’s stem cell policy, the letter written by the objecting members of the President’s Council on Bioethics continues: “Whether one agrees or not with the policy that had been in place for more than seven years, clarity and honesty require that we acknowledge its intent: to seek a way for science to proceed without violating the deep moral convictions of many of our fellow citizens. In many respects, that policy of seeking a way forward that would not violate widespread moral convictions had in fact succeeded – or, at least, seemed well on the way to achieving its aim. In 2005 this Council published a white paper titled ‘Alternative Sources of Human Pluripotent Stem Cells.’ At its outset, we stated our commitment to two goals: ‘advancing biomedical science and upholding ethical norms.’ We examined briefly four methods that had been proposed for procuring embryonic-like stem cells without destroying human embryos. We were not at that point in a position to endorse without hesitation any of them, but we concluded that we were ‘pleased to endorse these proposals as worthy of further public discussion, and … pleased to encourage their scientific exploration.’ Since the publication of that white paper, researchers have made progress on all of these methods – most strikingly in reprogramming somatic cells in order to restore them to a pluripotent condition. In the last two years, several different groups of scientists have succeeded in producing what are called induced pluripotent stem cells. Because producing them does not require the destruction of embryos, they do not raise what many regard as a grave moral difficulty. Because producing them does not require human ova, and because they are patient-specific stem cells that are less likely to be rejected by their recipients, they also have distinct scientific advantages. Indeed, on the day following President Obama’s announcement, an analysis in the New York Times noted that the embryonic stem cell research the President had touted ‘has been somewhat eclipsed by new advances.’ “

The letter also mentions “the position adopted by our predecessor body, the National Bioethics Advisory Commission, which did important work during the Clinton administration” and which, the letter points out, “approved stem cell research using (and, of course, destroying) embryos remaining after in vitro fertilization treatments. At the same time, however, NBAC stated that such embryo-destructive research is justifiable ‘only if no less morally problematic alternatives are available for advancing the research.’ Such alternatives are now available, and research on them is advancing.”

Additionally, the letter also points out that, “In his remarks on March 9, President Obama promised to ‘ensure that our government never opens the door to the use of cloning for human reproduction.’ While this may seem comforting, it stands in need of clarification. The president’s announced policy would permit federal funding of research not only on stem cell lines derived from ‘spare’ IVF embryos but also on lines derived from created and/or cloned embryos. In the latter two cases, we would be producing embryos simply in order to use them for our purposes.”

Along these lines, and as previously pointed out on this website, the authors of the letter emphasize the fact that, “What researchers most desire, in fact, are not spare IVF embryos but cloned embryos, produced in order to study disease models. The funding decision announced by the President on March 9 will encourage such cloning. Nor should we be reassured that, at the same time, the President opposed ‘the use of cloning for human reproduction.’ If cloned embryos are produced, they may be implanted and gestated. To prevent that, it will be necessary, as we noted in ‘Human Cloning and Human Dignity’, to prohibit, by law, the implantation of cloned embryos for the purpose of producing children. To do so, however, the government would find itself in the unsavory position of designating a class of embryos that it would be a felony not to destroy. We cannot believe that this would advance our society’s commitment to equal human dignity.”

As previously noted on this website, bioethics is a field which is not going to go away, and in fact entire departments that are focused on this very subject are springing up in law schools throughout the U.S. with increasing popularity, a prime example of which was the founding in 2005 by Harvard Law School of an entire center, “The Petrie-Flom Center for Health Law Policy, Biotechnology and Bioethics”, the entire purpose of which is precisely to provide a forum in which legal experts can debate and address, and formulate legislative policy on, such issues. With an increase in the number and types of new therapeutic modalities that are developed within the various medical specializations, the number and types of litigation are also expected to increase, and a new generation of lawyers who specialize in bioethics is currently being groomed to meet the future legal needs of a world that will be dramatically unlike the world for which current laws were authored. Even though doctors and scientists may not be formally addressing matters of medical bioethics, the lawyers are. If not because of a concern in ethics per se, then perhaps because of a concern in legal ramifications, the scientific and medical communities may find it in their interest to give some attention to the topic of bioethics.

In a personal statement issued by the Chairman of the President’s Council on Bioethics, Dr. Edmund D. Pellegrino states the following: “As an individual Council member, speaking for myself and not the President’s Council on Bioethics, I support the substance of the objections of some Council members to recent relaxation of existing policies regarding human embryonic stem cell research. Ethically, I cannot support any policy permitting deliberate production and/or destruction of a human fetus or embryo for any purpose, scientific or therapeutic.”

As President Obama himself has stated, it is “very important for us to have strong moral guidelines, ethical guidelines when it comes to stem cell research”. Nevertheless, Obama has thus far ignored completely the advice of the President’s Council on Bioethics, and he has even been described by many as “outsourcing ethical decisions to the National Institutes of Health”, even though it is certainly not within the purview of N.I.H. to formulate national legislation on bioethics.

In summary, the objecting members of the President’s Council on Bioethics contend not only that Obama has inadequately addressed the dangers of cloning but also that Obama has inaccurately characterized President Bush’s stem cell policy, which was advancing research within ethical norms more effectively than Obama’s policy will.

As the Council members conclude in regard to Obama’s decisions, “With respect to the progress that had been made in reconciling the needs of research and the moral concerns of many Americans, we can only judge, therefore, that the President’s action has taken a step backward, and we regret that.”

This news was reported by the Hastings Center which, as described on their website, is “a nonpartisan research institution dedicated to bioethics and the public interest since 1969.”