Illinois House Executive Committee Testimony
Mary J.C. Hendrix, PhD
President and Scientific Director
Children’s Memorial Research Center
Before the Illinois House Executive Committee
April 13, 2005
Chairman Burke, Vice-Chairman Lyons, Representative Kosel, and distinguished Members of the Committee, I am Mary Hendrix, and I am honored to have the opportunity to provide a scientific perspective on stem cell research. I am speaking to you today in support of HB 2249 as a scientist conducting cancer research, particularly on cancer stem cells, human embryonic stem cells, and normal adult stem cells, and as the president and scientific director of Children’s Memorial Research Center.
This bill is critically important to Illinois’ scientific community because it provides us a fiscally and ethically responsible way to explore the research potential of different types of stem cells that could lead to breakthrough cures for some of society’s most debilitating diseases.
The Illinois Regenerative Medicine Act would create an institute to fund both adult and embryonic stem cell research – essential to our understanding of the full potential of their prospective clinical application. This bill would also ban human reproductive cloning.
I. Deriving stem cells:
In 1998, scientists achieved a milestone in biomedical research. We learned that human embryonic stem cells could be isolated in the laboratory. Under the right conditions, these cells can differentiate into over 200 types of human cells, including nerve cells, heart cells, blood vessels, pancreatic cells, and many more – cells that have great potential for use in treatments of many diseases.
I will now explain precisely where these cells come from and the two ways they are derived:
- With a donor’s consent, they can be transplanted from embryos placed in frozen sanctuary at in vitro fertility clinics because they are in excess of a couple’s clinical need. A combination of sperm and egg yields a cell known as zygote. This cell divides over the course of 4-5 days into a blastocyst, a group of 150-200 cells so small that it can fit on the tip of a sewing needle. This entire process transpires outside of the body in cell cultures, and has been done for decades in fertility clinics. It is also important to note that a blastocyst cannot develop on its own into a human being unless successfully implanted into a woman’s uterus. Furthermore, we should also recognize that over the past two decades, thousands of blastocysts have been discarded – after they were no longer needed for uterine transplantation. Within the blastocyst is a group of 30-34 cells known as the inner cell mass. It is from this inner cell mass that embryonic stem cells are isolated. These cells are pluripotent, which means that they can divide indefinitely to produce as much tissue as needed for therapy, and they can be coaxed to develop into virtually any type of body cell.
- Stem cells can be derived through somatic cell nuclear transfer. This involves removing the nucleus of a donor’s unfertilized egg and replacing it with the nucleus of an adult cell, such as a skin, heart or nerve cell. No sperm is used in the procedure, and thus, there is no fertilization. The cell, with its new nucleus, is placed in a lab dish and stimulated to begin dividing. After a few days, it develops into a cellular ball from which researchers can transplant embryonic stem cells. The new cellular ball is never placed in a uterus and thus will not develop into a human being. What is unique about the stem cells derived from this process is that they are genetically identical to the individual in whom they will be transplanted, eliminating the danger of immune rejection and dramatically increasing the potential for successful therapy. For example, stem cells derived through this process from a person with a spinal cord injury could potentially be directed to develop into nerve cells which could be used to treat the same patient without risk of rejection.
I would like to briefly mention that we in the scientific community regard cloning for purposes of human reproduction to be unsafe, unethical, and unnecessary. That is why we strongly support the language in HB 2249 that will ban reproductive cloning in Illinois.
II. The Promise of Human Embryonic Stem Cell Research:
Having discussed the process of embryonic stem cell derivation and somatic cell nuclear transfer, I would like to now provide specific examples of ways in which this research may help cure devastating human diseases. I will limit my discussion to three major areas: Neurological Diseases, Juvenile Diabetes, and Cancer, although it is important to recognize that breakthroughs in biomedical research are occurring in many experimental disease models.
Diseases in which cells of the brain and spinal cord degenerate and die are among the most heart-wrenching of human afflictions. These devastating conditions rob millions of people of their ability to think, remember, communicate, or ambulate.
Parkinson's disease is a common condition in which people progressively lose their ability to control their movements, leading to difficulty walking, talking, or performing even simple tasks. In this condition, certain nerve cells in the brain which secrete a transmitter known as Dopamine degenerate and die. There is exciting evidence that these nerve cells can be replaced with new ones generated from embryonic stem cells. An Israeli research team made history in 2004 by using genetically modified human embryonic stem cells to relieve symptoms of Parkinson’s disease in rats.
Alzheimer's disease is a common condition in which nerve cells in certain regions of the brain degenerate and die. Sufferers progressively lose their ability to remember information and interact with their loved ones. New nerve cells derived from embryonic stem cells may be used to replace those destroyed by this devastating condition.
Recent research performed in rodents suggests that stem cells may also help repair traumatic injury to the nervous system. Spinal cord injuries from falls or motor vehicle accidents can cause paralysis, loss of sensation, and incontinence. In groundbreaking research, rats paralyzed from spinal cord injury regained their ability to walk after transplantation of specific nerve cells, called oligodendrocytes, that were derived from mouse embryonic stem cells.
Finally, using their own line of embryonic stem cells, researchers at the University of Wisconsin at Madison have become the first to make human motor neurons, the spindly nerve cells that control nearly all movement in the body. This is an important step in the goal of creating spinal nerve cells in the lab for use in replacing cells damaged by spinal cord injuries or by diseases such as Lou Gehrig's disease.
Juvenile Diabetes is a disease for which researchers are making rapid progress towards development of a cure using treatments derived from human embryonic stem cells. In this condition, children lose their ability to control the level of sugar in their blood. The average lifespan of these children is cut short by 15 years as they suffer from increased risks of heart disease, kidney disease, blindness, and amputation. This condition results from destruction of cells in the pancreas called islet cells which are responsible for producing insulin and regulating blood sugar levels.
Exciting research conducted by Dr. Kim and his colleagues at Stanford University is actually producing new pancreatic islet cells that secrete insulin from human embryonic stem cells. By deriving islet cells from human embryonic stem cells, these scientists are characterizing how these cells develop in order to determine how to successfully replace them and cure this condition. One current research strategy is to derive islet cells directly from human embryonic stems cells, analyze them in the laboratory, and evaluate their success in curing diabetic animals. If successful, these cells could be used in human transplants and could herald a cure for this devastating illness.
Millions of Americans suffer from different forms of cancer in which cancer cells divide uncontrollably, spread throughout the body, and destroy healthy tissue. While cancer therapy has made great strides in the past decade, patients struggle with the toxicity of chemotherapy and radiation therapy and in too many cases, we fail to cure these devastating conditions.
My area of expertise is cancer biology, and I can attest to the extraordinary promise of stem cell research in this realm. For example, an exciting discovery from the University of Texas M.D. Anderson Cancer Center recently demonstrated that stem cells can be engineered to act as “seek-and-destroy missiles” capable of finding cancer cells in animals and destroying them. Dr. Andreeff and colleagues took genetically altered stem cells and injected them into mice with tumors. The result was that millions of these engineered cells engrafted into the tumors and destroyed them. This innovative approach is being applied to models of leukemia, melanoma, breast cancer, ovarian cancer, and brain tumors.
In my own laboratory we have discovered the presence of cancer stem cells within aggressive human tumors. We are currently comparing these cancer stem cells to human embryonic stem cells and other adult stem cells to attempt to understand genetic similarities and differences – information that might be helpful in reversing the tendency of aggressive cancers to spread throughout the body.
Adult Stem Cells Are Useful But Have Important Limitations:
Let me conclude my discussion on the promise of embryonic stem cell research by addressing adult stem cells. I want to emphasize that embryonic and adult stem cell research are both extremely important. Both avenues of research must be pursued simultaneously to achieve the best results for those suffering from the diseases we hope to cure. HB 2249, and the Illinois Regenerative Medicine Institute it would create, provides funding that can be used for both adult and embryonic stem cell research. I want to clarify that although these areas of research complement one another, these cells are not necessarily interchangeable.
In fact, our current understanding is that adult stem cells have several major limitations in comparison with embryonic stem cells that directly affect their potential to develop cures for diseases.
First, it is difficult to identify and isolate adult pluripotent stem cells. Many of these cells are found in limited numbers in regions of the body that are difficult to safely access.
Secondly, adult stem cells appear to be much more restricted in their ability to differentiate into the wide range of cell types present in the human body. Contrary to prior reports, the most recent reliable evidence from the University of California and several other institutions indicate that adult stem cells cannot give rise to all cell types in the body.
Finally, the ability of adult stem cells to replicate is not as robust as embryonic stem cells. Thus it is more difficult to generate the amount of tissue required for many types of transplantation.
Another promising source of stem cells is cord blood, which is generally discarded with the placenta at the time of birth. I have had the privilege of working with the inventors of the technology to isolate stem cells from cord blood, Drs. Edward Boyce, Judith Bard and Hal Broxmeyer. My esteemed colleagues have been working with cord blood stem cells since the 1980s, and they would be the first to testify that the full potential of these cells with respect to their pluripotency (or “stemness”) is unknown at this time.
Given these current limitations of adult stem cells in comparison to embryonic stem cells, and the unknown potential of cord blood stem cells, it is critical that we keep all avenues of stem cell research open until additional research reveals the most effective ways to treat various diseases.
III. The need for HB 2249
In 2001, the President announced that the National Institutes of Health may fund research on human embryonic stem cell lines derived before August 9, 2001. Only cells derived from excess embryos left over from fertility clinics may be used.
In January 2005, researchers at the University of California, San Diego found conclusive proof that all of these human embryonic stem cell lines available for use in federally funded research are contaminated with animal molecules from the culture medium used to sustain them.
Private funding can support research on stem cell lines derived after the President’s decision; however, this research is not subject to public oversight and thus lacks the transparency of government-funded research, and particularly valuable public input. Currently, several states are considering funding mechanisms to support this research in response to the federal government’s current policy. These states include California, in which voters approved a $3 billion bond initiative to fund stem cell research, New York, New Jersey, Wisconsin, Maryland, Connecticut, and Massachusetts.
The proposal introduced in HB 2249 presents us with an ethically and fiscally responsible way to allow Illinois to maintain its position as a national leader in research and to continue to attract world-renowned researchers and physicians. Illinois is home to some of the top academic medical centers in the country - each one is a pioneer in medical research and clinical practice. Each one of these institutions is a national leader, and collectively they influence and guide the future of medicine.
We have an obligation to promote the best medical science for all Illinois citizens, who will reap the benefits of our scientific expertise if you allow them. With your help, we will better understand and ultimately cure many devastating diseases. But the first step on the long road towards these cures is state investment in this essential research.
In conclusion, I urge you to support HB 2249 to create and fund the Illinois Regenerative Medicine Institute. With your support, we can provide scientists and clinicians in Illinois the opportunity to move forward ethically and in a fiscally responsible way towards ushering in the next generation of medical breakthroughs and treatments. Thank you for your serious consideration of this legislation.