Embryonic Stem Cell Research 1 Running Head: EMBRYONIC STEM CELL RESEARCH Embryonic Stem Cell Research Leanne Danekas Jenna Felesena Jessica Tartaglione BIO 3400 Professor Chen December 5, 2007 Embryonic Stem Cell Research 2 Embryonic Stem Cell Research Embryonic stem cell research had been the cause of controversy for several years. There are many ethical reasons for and against this idea, but what are the medical reasons? These small cells have the ability to save lives by creating new tissues and organs. Ongoing research shows promise that embryonic stem cells could also aid in curing diseases like Parkinson’s disease and Alzheimer’s disease. Although there are numerous ethical reasons against the use of embryonic stem cell research, the positive medical outcomes should be a major argument for research to continue. Stem cells are found in all multi-cellular organisms and they “retain the ability to renew themselves through mitotic cell division” (Stem Cell, 2007). They have the ability to change into a wide variety of cells. Stem cells grow and transform as they get older and then have more specialized tasks. There are two types of stem cells: adult stem cells, and embryonic stem cells. Adult stem cells are found in adult mammals and are used mostly to repair cells. Embryonic stem cells “are stem cells derived from the inner cell mass of an early stage embryo known as a blastocyst” (Embryonic Stem Cell, 2007). The advantage of using embryonic stem cells for research is that they can develop into any other type of cell in the body. Therefore, there are a wide variety of uses for the embryonic stem cell. This wide variety of uses allows for many different types of genetic research. It is very difficult to study human development at such an early stage. “Human embryonic stem cells offer insights into the developmental events that cannot be studied directly in humans in utero, or fully understood through the use of animal models” (Embryonic Stem Cell: Research, 2007). These studies can help prevent infertility and birth defects. Embryonic Stem Cell Research 3 “Because of their plasticity and potentially unlimited capacity for self-renewal, embryonic stem cell therapies have been proposed for regenerative medicine and tissue replacement after injury or disease” (Embryonic Stem Cell, 2007). This also allows for geneticists to grow and develop these stem cells into specified cells for medical importance. Instead of relying on donors for different organs, stem cells give doctors the opportunity to grow the bone marrow, organs, tissue, and muscle that is necessary to save lives. These embryonic stem cells can help reduce the risk of getting a transplant, as well as for the donor (if they are still alive). Doctors can also potentially remove the cells of a patient with a disease and replace them with the new stem cells. Most of these doctors have difficulty getting an appropriate amount of embryonic stem cells for the proper research due to ethical issues and laws within the government. Another option was to take stem cells from adults. Taking stem cells from adults would not be very helpful because the adult stem cells are already specialized for specific functions. For example: “skin cells will only become skin cells and cartilage cells will only become cartilage” (Embryonic Stem Cells, 2007). Also, when adult tissues are damaged, scar tissue forms because adults do not have many stem cells in certain organs. As a result, embryonic stem cells provide a better medical option in the study of human development. There are several individuals in the scientific community who are adamant that embryonic stem cell research contains the answer to cure many conditions and diseases. Several Americans suffer from diseases that could be treated or possibly cured more effectively with embryonic stem cell therapy. Embryonic stem cells have a greater Embryonic Stem Cell Research 4 plasticity, allowing them to treat a wider range of diseases. These include diabetes, multiple sclerosis, spinal cord injuries, heart disease, Parkinson’s disease, Alzheimer’s disease, and cancer. Stem cells are the forerunner of all the different cell types in a human body. By growing stem cells in a laboratory, scientists anticipate uncovering the signals that make them increase into specific tissues. Scientists see embryonic stem cell research as a way to better understand human development and also the growth and development of diseases. Stem cell research also benefits the study of events that are not able to be studied in a human embryo. Another great advantage that stem cell research has is the ability to test several medicines without the use of human or animals as testers. This would determine if the drug is either useful or problematic. Stem cell research also contains the key to reverse the effects of aging and prolong lives. Embryonic stem cells are beneficial because they have a lower incidence of rejection and they are the youngest stem cells available for use in treatment. Although there has not been anybody cured by embryonic stem cell research, scientists are determined that in the future embryonic stem cells will be the answer to curing many diseases. In creating embryonic stem cells for research, a stem cell line must be created first and this is done using the inner cell mass of a week-old embryo. If the stem line is cultured properly, then the embryonic stem cells will grow and divide indefinitely. The stem cell line consists of a mass of cells descended from the original, sharing the genetic characteristics. Then, groups of cells can be separated and given to researchers (Fact Sheet, 2001). The cells from embryonic stem cells would be injected directly into patients. Embryonic Stem Cell Research 5 There are numerous benefits to the development of embryonic stem cell research and there are still some drawbacks that need to be considered. Those mostly opposed to the development of embryonic stem cell research are considered pro-life. An embryo is technically not alive because it cannot survive outside the womb, but pro-life believes that it is still considered killing a human. In their opinions, extracting and destroying a live embryo is considered abortion, which is condoned by many religious groups. There are many ethical arguments against embryonic stem cell research, but there are medical arguments which must be considered as well. Popular Issue (2007) states that “mice treated for Parkinson’s with embryonic stem cells have died from brain tumors in as much as 20% of cases” (Popular Issue, para. 6). This is evidence that an older embryonic stem cell can create chromosomal irregularities, which can cause cancerous cells. Not only does embryonic stem cell research have the potential to cause cancer, but it takes away from the current research of adult stem cell research. Many opponents of embryonic stem cell research believe that more time, money, and experimentation should be focused on adult stem cell research instead. This is because embryos’ would not be used in experimentation and the ethical dilemmas are averted. Though the medical community questions whether the risks of stem cells are worth the benefits, science is designed to evolve. When new discoveries are made, it is vital to explore and experiment on them. Without this ability, the world may never see a cure for cancer, Parkinson’s disease, and/or Alzheimer’s disease. Embryonic stem cell research needs to be funded and looked into more because it could be the key to many new advances in the scientific community. Although there are numerous ethical reasons Embryonic Stem Cell Research 6 against the use of embryonic stem cell research, the positive medical outcomes should be a major argument for research to continue. Embryonic Stem Cell Research 7 References All About Popular Issues: Pros and Cons of Stem Cell Research. (2007). Retrieved November 15, 2007, from http://www.allaboutpopularissues.org/pros-and-cons- of-stem-cell-research.htm Embryonic Stem Cell. (2007). In Wikipedia online encyclopedia. Retrieved November 15, 2007, from http://en.wikipedia.org/wiki/Embryonic_stem_cell_research Embryonic Stem Cells: Research at the University of Wisconsin-Madison. (2007). Retrieved November 15, 2007, from http://www.news.wisc.edu/packages/stemcells/facts.html#4 Fact Sheet: Embryonic Stem Cell Research. (2001). Retrieved November 15, 2007, from http://www.whitehouse.gov/news/releases/2001/08/20010809-1.html Stem Cell. (2007). In Wikipedia online encyclopedia. Retrieved November 15, 2007, from http://en.wikipedia.org/wiki/Stem_cell Embryonic Stem Cell Research 8 Stem Cell. (2007). In Wikipedia online encyclopedia. Retrieved November 15, 2007, from http://en.wikipedia.org/wiki/Stem_cell Stem cells are cells found in all multi-cellular organisms. They retain the ability to renew themselves through mitotic cell division and can differentiate into a diverse range of specialized cell types. Research in the stem cell field grew out of findings by Canadian scientists Ernest A. McCulloch and James E. Till in the 1960s. The two broad types of mammalian stem cells are: embryonic stem cells that are found in blastocysts, and adult stem cells that are are found in adult tissues. In a developing embryo, stem cells can differentiate into all of the specialized embryonic tissues. In adult organisms, stem cells and progenitor cells act as a repair system for the body, replenishing specialized cells, but also maintain the normal turnover of regenerative organs, such as blood, skin or intestinal tissues. As stem cells can be grown and transformed into specialized cells with characteristics consistent with cells of various tissues such as muscles or nerves through cell culture, their use in medical therapies has been proposed. In particular, embryonic cell lines, autologous embryonic stem cells generated through therapeutic cloning, and highly plastic adult stem cells from the umbilical cord blood or bone marrow are touted as promising candidates. Embryonic Stem Cell. (2007). In Wikipedia online encyclopedia. Retrieved November 15, 2007, from http://en.wikipedia.org/wiki/Embryonic_stem_cell_research Embryonic stem cells (ES cells) are stem cells derived from the inner cell mass of an early stage embryo known as a blastocyst. Human embryos reach the blastocyst stage 4-5 days post fertilization, at which time they consist of 50-150 cells. ES cells are pluripotent. This means they are able to differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. These include each of the more than 220 cell types in the adult body. Pluripotency distinguishes ES cells from multipotent progenitor cells found in the adult; these only form a limited number of cell types. When given no stimuli for differentiation, (i.e. when grown in vitro), ES cells maintain pluripotency through multiple cell divisions. The presence of pluripotent adult stem cells remains a subject of scientific debate, however, research has demonstrated that pluripotent stem cells can be directly generated from adult fibroblast cultures.. Because of their plasticity and potentially unlimited capacity for self-renewal, ES cell therapies have been proposed for regenerative medicine and tissue replacement after injury or disease. However, to date, no approved medical treatments have been derived from embryonic stem cell research (ESCR). Adult stem cells and cord blood stems cells have thus far been the only stem cells used to successfully treat any diseases. Diseases treated by these non-embryonic stem cells include a number of blood and immune-system related genetic diseases, cancers, and disorders; juvenile diabetes; Parkinson's; blindness and spinal cord injuries. Besides the ethical problems of stem cell therapy (see stem cell controversy), there is a technical problem of graft-versus-host disease associated with allogeneic stem cell transplantation. However, these problems associated with histocompatibility may be solved using autologous donor adult stem cells or via therapeutic cloning. Embryonic Stem Cell Research 9 Embryonic Stem Cells: Research at the University of Wisconsin-Madison. (2007). Retrieved November 15, 2007, from http://www.news.wisc.edu/packages/stemcells/facts.html#4 Why are embryonic stem cells important? Embryonic stem cells are of great interest to medicine and science because of their ability to develop into virtually any other cell made by the human body. In theory, if stem cells can be grown and their development directed in culture, it would be possible to grow cells of medical importance such as bone marrow, neural tissue or muscle. The first potential applications of human embryonic stem cell technology may be in the area of drug discovery. The ability to grow pure populations of specific cell types offers a proving ground for chemical compounds that may have medical importance. Treating specific cell types with chemicals and measuring their response offers a short-cut to sort out chemicals that can be used to treat the diseases that involve those specific cell types. Stem cell technology, therefore, would permit the rapid screening of hundreds of thousands of chemicals that must now be tested through much more time-consuming processes. The study of human development also benefits from embryonic stem cell research. The earliest stages of human development have been difficult or impossible to study. Human embryonic stem cells offer insights into developmental events that cannot be studied directly in humans in utero or fully understood through the use of animal models. Understanding the events that occur at the first stages of development has potential clinical significance for preventing or treating birth defects, infertility and pregnancy loss. A thorough knowledge of normal development could ultimately allow the prevention or treatment of abnormal human development. For instance, screening drugs by testing them on cultured human embryonic stem cells could help reduce the risk of drug-related birth defects. Why are embryonic stem cells important? Embryonic stem cells are of great interest to medicine and science because of their ability to develop into virtually any other cell made by the human body. In theory, if stem cells can be grown and their development directed in culture, it would be possible to grow cells of medical importance such as bone marrow, neural tissue or muscle. The first potential applications of human embryonic stem cell technology may be in the area of drug discovery. The ability to grow pure populations of specific cell types offers a proving ground for chemical compounds that may have medical importance. Treating specific cell types with chemicals and measuring their response offers a short-cut to sort out chemicals that can be used to treat the diseases that involve those specific cell types. Stem cell technology, therefore, would permit the rapid screening of hundreds of thousands of chemicals that must now be tested through much more time-consuming processes. The study of human development also benefits from embryonic stem cell research. The earliest stages of human development have been difficult or impossible to study. Human embryonic stem cells offer insights into developmental events that cannot be studied directly in humans in utero or fully understood through the use of animal models. Understanding the events that occur at the first stages of development has potential clinical significance for preventing or treating birth defects, infertility and pregnancy loss. A thorough knowledge of normal development could ultimately allow the prevention or treatment of abnormal human development. For instance, Embryonic Stem Cell Research 10 screening drugs by testing them on cultured human embryonic stem cells could help reduce the risk of drug-related birth defects. How might embryonic stem cells be used to treat disease? The ability to grow human tissue of all kinds opens the door to treating a range of cell-based diseases and to growing medically important tissues that can be used for transplantation purposes. For example, diseases like juvenile onset diabetes mellitus and Parkinson's disease occur because of defects in one of just a few cells types. Replacing faulty cells with healthy ones offers hope of lifelong treatment. Similarly, failing hearts and other organs, in theory, could be shored up by injecting healthy cells to replace damaged or diseased cells. Why not derive stem cells from adults? There are several approaches now in human clinical trials that utilize mature stem cells (such as blood-forming cells, neuron-forming cells and cartilage-forming cells). However, because adult cells are already specialized, their potential to regenerate damaged tissue is very limited: skin cells will only become skin and cartilage cells will only become cartilage. Adults do not have stem cells in many vital organs, so when those tissues are damaged, scar tissue develops. Only embryonic stem cells, which have the capacity to become any kind of human tissue, have the potential to repair vital organs. Another limitation of adult stem cells is their inability to proliferate in culture. Unlike embryonic stem cells, which have a capacity to reproduce indefinitely in the laboratory, adult stem cells are difficult to grow in the lab and their potential to reproduce diminishes with age. Therefore, obtaining clinically significant amounts of adult stem cells may prove to be difficult. Studies of adult stem cells are important and will provide valuable insights into the use of stem cell in transplantation procedures. However, only through exploration of all types of stem cell research will scientists find the most efficient and effective ways to treat diseases. Fact Sheet: Embryonic Stem Cell Research. (2001). Retrieved November 15, 2007, from http://www.whitehouse.gov/news/releases/2001/08/20010809-1.html Fact Sheet: Embryonic Stem Cell Research "As a result of private research, more than 60 genetically diverse stem cell lines already exist" I have concluded that we should allow federal funds to be used for research on these existing stem cell lines " where the life and death decision has already been made", This allows us to explore the promise and potential of stem cell research" without crossing a fundamental moral line by providing taxpayer funding that would sanction or encourage further destruction of human embryos that have at least the potential for life." -- George W. Bush Federal funding of research using existing embryonic stem cell lines is consistent with the President's belief in the fundamental value and sanctity of human life. The President's decision reflects his fundamental commitment to preserving the value and sanctity of human life and his desire to promote vital medical Embryonic Stem Cell Research 11 research. The President's decision will permit federal funding of research using the more than 60 existing stem cell lines that have already been derived, but will not sanction or encourage the destruction of additional human embryos. The embryos from which the existing stem cell lines were created have already been destroyed and no longer have the possibility of further development as human beings. Federal funding of medical research on these existing stem cell lines will promote the sanctity of life " without undermining it " and will allow scientists to explore the potential of this research to benefit the lives of millions of people who suffer from life destroying diseases. Federal funds will only be used for research on existing stem cell lines that were derived: (1) with the informed consent of the donors; (2) from excess embryos created solely for reproductive purposes; and (3) without any financial inducements to the donors. In order to ensure that federal funds are used to support only stem cell research that is scientifically sound, legal, and ethical, the NIH will examine the derivation of all existing stem cell lines and create a registry of those lines that satisfy this criteria. More than 60 existing stem cell lines from genetically diverse populations around the world are expected to be available for federally-funded research. No federal funds will be used for: (1) the derivation or use of stem cell lines derived from newly destroyed embryos; (2) the creation of any human embryos for research purposes; or (3) the cloning of human embryos for any purpose. Today's decision relates only to the use of federal funds for research on existing stem cell lines derived in accordance with the criteria set forth above. The President will create a new President's Council on Bioethics, chaired by Dr. Leon Kass, an expert in biomedical ethics and a professor at the University of Chicago, to study the human and moral ramifications of developments in biomedical and behaviorial science and technology. The Council will study such issues as embryo and stem cell research, assisted reproduction, cloning, genetic screening, gene therapy, euthanasia, psychoactive drugs, and brain implants. BACKGROUND Embryonic stem cells. Embryonic stem cells, which come from the inner cell mass of a human embryo, have the potential to develop into all or nearly all of the tissues in the body. The scientific term for this characteristic is "pluripotentiality." Adult stem cells. Adult stem cells are unspecialized, can renew themselves, and can become specialized to yield all of the cell types of the tissue from which they originate. Although scientists believe that some adult stem cells from one tissue can develop into cells of another tissue, no adult stem cell has been shown in culture to be pluripotent. The potential of embryonic stem cell research. Many scientists believe that embryonic stem cell research may eventually lead to therapies that could be used to treat diseases that afflict approximately 128 million Americans. Treatments may include replacing destroyed dopamine-secreting neurons in a Parkinson's patient's brain; transplanting insulin-producing pancreatic beta cells in diabetic patients; and infusing cardiac muscle cells in a heart damaged by myocardial infarction. Embryonic stem cells may also be used to understand basic biology and to evaluate the safety and efficacy of new medicines. Embryonic Stem Cell Research 12 The creation of embryonic stem cells. To create embryonic stem cells for research, a "stem cell line" must be created from the inner cell mass of a week-old embryo. If they are cultured properly, embryonic stem cells can grow and divide indefinitely. A stem cell line is a mass of cells descended from the original, sharing its genetic characteristics. Batches of cells can then be separated from the cell line and distributed to researchers. The origin of embryonic stem cells. Embryonic stem cells are derived from excess embryos created in the course of infertility treatment. As a result of standard in vitro fertilization practices, many excess human embryos are created. Participants in IVF treatment must ultimately decide the disposition of these excess embryos, and many individuals have donated their excess embryos for research purposes. Existing stem cell lines. There are currently more than 60 existing different human embryonic stem cell lines that have been developed from excess embryos created for in vitro fertilization with the consent of the donors and without financial inducement. These existing lines are used in approximately one dozen laboratories around the world (in the United States, Australia, India, Israel, and Sweden). Therapies from adult and embryonic stem cell research. To date, adult stem cell research, which is federally-funded, has resulted in the development of a variety of therapeutic treatments for diseases. Although embryonic stem cell research has not yet produced similar results, many scientists believe embryonic stem cell research holds promise over time because of the capacity of embryonic stem cells to develop into any tissue in the human body. All About Popular Issues: Pros and Cons of Stem Cell Research. (2007). Retrieved November 15, 2007, from http://www.allaboutpopularissues.org/pros-and- cons-of-stem-cell-research.htm Pros and Cons of Stem Cell Research - What are Stem Cells? There has been much controversy in the press recently about the pros and cons of stem cell research. What is the controversy all about? "Stem" cells can be contrasted with "differentiated" cells. They offer much hope for medical advancement because of their ability to grow into almost any kind of cell. For instance, neural cells in the brain and spinal cord that have been damaged can be replaced by stem cells. In the treatment of cancer, cells destroyed by radiation or chemotherapy can be replaced with new healthy stem cells that adapt to the affected area, whether it be part of the brain, heart, liver, lungs, or wherever. Dead cells of almost any kind, no matter the type of injury or disease, can be replaced with new healthy cells thanks to the amazing flexibility of stem cells. As a result, billions of dollars are being poured into this new field. Pros and Cons of Stem Cell Research - Where Do They Come From? To understand the pros and cons of stem cell research, one must first understand where stem cells come from. There are three main sources for obtaining stem cells - adult cells, cord cells, and embryonic cells. Adult stem cells can be extracted either from bone marrow or from the peripheral system. Bone marrow is a rich source of stem cells. However, some painful destruction of the bone marrow results from this procedure. Peripheral stem cells can be extracted without damage to bones, but the process takes more time. And with health issues, time is often of the essence. Although difficult to extract, since they are taken from the patient's own body, adult stem cells are superior to both umbilical cord and embryonic stem cells. They are plentiful. There is always an exact DNA match so the body's immune system never rejects them. And as we might expect, results have been both profound and promising. Embryonic Stem Cell Research 13 Stem cells taken from the umbilical cord are a second very rich source of stem cells. Umbilical cells can also offer a perfect match where a family has planned ahead. Cord cells are extracted during pregnancy and stored in cryogenic cell banks as a type of insurance policy for future use on behalf of the newborn. Cord cells can also be used by the mother, the father or others. The more distant the relationship, the more likely it is that the cells will be rejected by the immune system's antibodies. However, there are a number of common cell types just as there are common blood types so matching is always possible especially where there are numerous donors. The donation and storage process is similar to blood banking. Donation of umbilical cells is highly encouraged. Compared to adult cells and embryonic cells, the umbilical cord is by far the richest source of stem cells, and cells can be stored up in advance so they are available when needed. Further, even where there is not an exact DNA match between donor and recipient, scientists have developed methods to increase transferability and reduce risk. Pros and Cons of Stem Cell Research - Embryonic Cells The pros and cons of stem cell research come to the surface when we examine the third source of stem cells - embryonic cells. Embryonic stem cells are extracted directly from an embryo before the embryo's cells begin to differentiate. At this stage the embryo is referred to as a "blastocyst." There are about 100 cells in a blastocyst, a very large percentage of which are stem cells, which can be kept alive indefinitely, grown in cultures, where the stem cells continue to double in number every 2-3 days. A replicating set of stem cells from a single blastocyst is called a "stem cell line" because the genetic material all comes from the same fertilized human egg that started it. President Bush authorized federal funding for research on the 15 stem cell lines available in August 2001. Other stem cell lines are also available for research but without the coveted assistance of federal funding. So what is the controversy all about? Those who value human life from the point of conception, oppose embryonic stem cell research because the extraction of stem cells from this type of an embryo requires its destruction. In other words, it requires that a human life be killed. Some believe this to be the same as murder. Against this, embryonic research advocates argue that the tiny blastocyst has no human features. Further, new stem cell lines already exist due to the common practice of in vitro fertilization. Research advocates conclude that many fertilized human cells have already been banked, but are not being made available for research. Advocates of embryonic stem cell research claim new human lives will not be created for the sole purpose of experimentation. Others argue against such research on medical grounds. Mice treated for Parkinson's with 1 embryonic stem cells have died from brain tumors in as much as 20% of cases. Embryonic stem cells stored over time have been shown to create the type of chromosomal anomalies that create 2 cancer cells. Looking at it from a more pragmatic standpoint, funds devoted to embryonic stem cell research are funds being taken away from the other two more promising and less controversial types of stem cell research mentioned above.
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