Stem Cells and the Future of Regenerative Medicine
Bert Vogelstein, M.D.
Chairman, Biological and Biomedical Applications of Stem Cell Research Committee
National Research Council and Institute of Medicine
Professor of Oncology and Pathology
Johns Hopkins Oncology Center and the Howard Hughes Medical Institute
Concerning Stem Cells
Subcommittee on Labor, Health and Human Services, Education, and Related Agencies
Committee on Appropriations
October 31, 2001
Good morning, Mr. Chairman, and members of the Committee. My name is Bert Vogelstein and I am a Professor of Oncology and Pathology at the John Hopkins Oncology Center and a Howard Hughes Medical Institute Investigator. I am here today as the chairman of a National Research Council and Institute of Medicine Committee on the Biological and Biomedical Applications of Stem Cell Research which on September 11 released the report Stem Cells and the Future of Regenerative Medicine.
Stem cell research gives hope to millions of Americans and people around the world who suffer from debilitating illnesses such as diabetes and Parkinson's disease--or who have suffered injuries to their spinal cords or other parts of the body--that new treatments and perhaps even a cure will someday make them well again.
Given that promise, as well as the ethical controversies it generates, the National Research Council and Institute of Medicine decided it would be a good idea to form a committee to take a look at how promising stem cell research really is; how far away we are from practical, therapeutic applications; and what factors might either promote or hinder progress in the development of stem cell therapies.
Our committee also took into consideration the fact that there are diverse views held in our society about the ethical controversies stem cell research raises. We included an expert in bioethics on our committee and invited philosophers, ethicists, religious leaders, and legal experts to a workshop we held on the scientific and ethical issues of stem cell research this past summer so we could listen to their views.
It is important to note that none of the members of our committee are conducting stem cell research ourselves, and none have financial interests in stem cell research. This was to assure that none of us had a vested self-interest in the outcome of this report.
Realizing the importance of stem cell research, The National Academies not only initiated but also funded most of this study itself, with additional support from the Ellison Foundation, to whom we are grateful.
It should be pointed out that we recognize that the role of the National Academies is to advise public policy, not set it. The purpose of our report was to tell policymakers what we know about the potential of stem cell research based on the best available science, but it is up to the government, and really all of society, to consider our advice and make decisions.
Let me give you a brief description of what stem cells are and what we know about their potential to be used as medical therapies, before I get to our findings and recommendations.
Stem cells are unspecialized cells that can renew themselves indefinitely, and under the right conditions, become, or differentiate into, cell types with specialized functions. They can be found in an embryo in the very early stages of development, in some fetal tissue, and in some adult organs.
Isolating adult stem cells is very difficult and there is only preliminary evidence that they can be turned into tissue characteristic of organs other than the ones from which they were taken. On the other hand, since 1998, we have been able to grow embryonic stem cells in the laboratory. In addition, embryonic stem cells are known to have the ability to differentiate into virtually all cell types. Researchers have had some success using transplanted embryonic stem cells from mice to restore some lost functions in diseased or injured animals. We found these studies to be promising, but not definitive, evidence that similar treatments can be successful in humans.
Let me now briefly summarize the committee's main recommendations:
First, although experiments in mice and other animals are necessary, they are not sufficient for realizing the full potential of stem cells to lead to tissue-replacement therapies for humans. Studies with human stem cells are absolutely necessary.
Second, although stem cell research is on the cutting edge of science today, it is still in its infancy. Current scientific data indicate that there are important biological differences between adult and embryonic stem cells and among adult stem cells found in different types of tissue. The therapeutic implications of these biological differences are not yet clear. Adult stem cells from bone marrow have so far provided most of the examples of successful therapies for replacement of diseased or destroyed cells. However, their potential for fully differentiating into multiple tissue types is still poorly understood and remains to be clarified. In contrast, embryonic stem cells studied in animals clearly are capable of developing into multiple tissue types and are capable of long-term self-renewal in culture. Because the application of stem cell research to therapy for human disease will require much more knowledge about the biological properties of all types of stem cells, research on both embryonic and adult human stem cells should be pursued.
Third, while much can be learned from existing embryonic stem cell lines if they are made widely available for research, concerns about the eventual accumulation of genetic mutations in these lines, and the fact that most have been cultured with animal cells and serum, means they need to be monitored very closely and that we will need to develop new stem cell lines in the future.
Fourth, human stem cell research that is publicly funded and conducted under the highest standards of open scientific exchange, peer-review, and public oversight offers the most efficient and responsible means to achieve medical breakthroughs. Stem cell science is still in the early stages where much more basic research is needed. Although research by private, for-profit companies will eventually play a critical role in translating the fruits of basic research into actual medical therapies, it is likely to take years to yield commercial products. Without public funding for basic research to get us to that point, progress is likely to be hindered.
Fifth, proposals for federal grants to work on human embryonic stem cells should be justified on the soundest scientific grounds and should be strictly scrutinized for compliance with existing and future federally-mandated ethical guidelines.
Sixth, we recommend that to assist in providing scientific and ethical oversight, a national advisory body composed of leading scientists, ethicists, and other stakeholders be established at the National Institutes of Health. This group could evaluate the technical merit of research proposals, monitor potential risks to research subjects, and ensure compliance with the law and ethical standards.
Our final recommendation is that in conjunction with research on stem cell biology and the development of stem cell therapies, research on the problem of transplant rejection should also be actively pursued. A substantial obstacle to the success of transplantation of any cells, including stem cells and their derivatives, is the immune reaction of a patient’s body to cells that it perceives as foreign. Multiple approaches to reducing this problem should be explored, including ways to manipulate the genetic makeup of the stem cell tissue to make it less likely to provoke an immune reaction, and the creation of stem cells using a technique known as somatic cell nuclear transfer. This involves taking the DNA from a cell of a patient in need of a transplant, inserting it into an egg cell that has had its nucleus removed, and triggering cell division. The resulting stem cells and tissue that can be obtained from this procedure would be genetically identical to the patient’s, and would in theory not be rejected by the patient’s immune system when transplanted into him or her.
This procedure should not be confused with reproductive cloning which utilizes a similar technique for the purpose of implanting an embryo and creating a child. The issue of reproductive cloning is being looked at by another National Academies committee, which will issue its findings soon.
I would like to end by emphasizing again that stem cell research is in its infancy. Our committee is respectful of the wide array of social, political, legal, ethical, and economic issues that must be considered in policy-making in a democracy, and we have been impressed by the commitment of all parties in this debate to life and health, regardless of the different conclusions they draw. We hope our report, by clarifying what is known about stem cells and how best to realize their potential, will be a useful contribution to the discussion of this important issue.
Thank you for this opportunity to testify. I would like my statement to be put into the record, and I will be happy to answer any questions the Committee might have.