Majority of the cells in animals or human beings can only fulfill a single function in the body. Stem cells in contrast are unique cells in that they retain the ability to become some or all of the more than 200 different cells in the body and thereby play a critical role in repairing organs and body tissues throughout life. The term stem cell is often used to refer to these repair cells in an adult organism though more varieties of stem cells are found in a developing embryo when it is in its early stages. These embryonic stem cells possess a high ability to develop into different types of body cells than adult stem cells. Scientists have therefore focused themselves in studying and developing embryonic stem cells. It is hoped that stem cell science will yield treatment for chronic and debilitating diseases such as cancer, diabetes, Parkinson's disease and epilepsy among others.
The research has not been without controversy. A significant portion of the society believes embryonic stem research should be stopped because it involves destruction of the embryo which is potentially a human being. The conservative Christians, mainly a portion of Protestants, and the Buddhist have vehemently opposed embryonic stem cell research. Although conservative Christians and Buddhist believe that embryonic stem cell research should be prohibited for moral and ethical reasons, I am of the opinion that all types of stem cell research should continue for the potential benefits they have in saving human life. This paper is going to present an argument in support of stem cell research and its actual and potential benefits in saving human life by providing a cure for many terminal illnesses that claim millions of lives every year.
McWay (2009:140) defines stem cell research as "the careful, systematic study of, and investigation of a special kind of cell not committed to conduct a specific function that has the ability to renew itself and differentiate into specialized cells." The cells cannot however differentiate into specific specialized cells until they are given signals to that effect. It is this ability to differentiate into a variety of specialized cells that makes scientist believe that stem cells hold a cure for many of the chronic diseases.
Stem cell are derived from two sources; adult stem cells that are mainly gotten from the bone marrow or skin cells and embryonic cells that are derived from early human embryos. The adult stem cell research is considered less controversial because it utilizes cells from adults without harming those involved. The embryonic stem cells research is however considered very controversial in some people's opinion because the stem cells used are derived from an embryo and the process of extracting them ends up destroying the embryo. They are however the most preferred by scientist due to the fact that they are easy to identify and readily available unlike the adult stem cells which are considered rare and difficult to identify (McWay, 2009:140).
The history stem cell can be traced back to the mid 1800s when scientists discovered in that cell are the basic building blocks of life. In the 1900s, scientists discovered that all blood cells emanate from one particular cell called stem cell. With more research on stem cells, scientist discovered that these cells can be utilized in various ways. It was in 1968 when scientist made a breakthrough in use of stem cells when they performed the first successful bone marrow transplant, a procedure that involves infusion of hematopoietic adult stem cells residing in the bone marrow into the patient. With further research, scientists were able to isolate the first embryonic stem cells from mice embryos in 1981. In 1995 scientists isolated for the first time stem cells from a primate embryo. Through further research, scientist at University of Wisconsin isolated the first human embryonic stem cells and researchers at John Hopkins University from human germ cells in 1998 (Panno, 2005).
To understand what stem cells are and where they are derived from, it is important to pay attention to the formation of a human embryo. The life of a human being starts when the sperm fertilizes the egg to form a single cell called a zygote (Novak, 2007). A zygote divides itself into two cells with each of these cells dividing themselves time and again. After a period of five days after conception the dividing cells form a hallow ball of about 150 cells called the blastocyst. The blastocyst contains two types of cells, the trophoblast and the inner cell mass. The embryonic stem cells are the cells that make up the inner cell mass. These cells are said to be totipotent meaning they can generate all types of cells and tissues. Embryonic stem cells can divide themselves into over 200 types of cells. The blastocyst contains about 200-250 cells that are totipotent specializing into an outer layer called the placenta and an inner layer called the epiblast (Panno, 2005). It is the epiblast that houses the embryonic stem cells. The human embryonic cells are therefore derived from the blastocyst.
The other type of human stem cell is the human embryonic germ cell that was separated for the first time in 1998 by a research team at John Hopkins hospital led by John Gearhart. Human embryonic germ cells are derived from primordial germ cells found on the gonadal region of the embryo. They are separated during the fourth or fifth week of a fetus development. The cells eventually develop into gametes. Concern has been raised about the use of these stem cells since by the time of isolation, the cells have already specialized. The human embryonic stem cell and human germ cells have similarities and differences too. Embryonic cells are derived from epiblast while the germ cells are derived from the gonadol region of a fetus. The embryonic cells multiply faster than the germ cells. Both types however produce male and female cultures, they are pluripotent and free of chromosomal abnormalities. They also possess a long life.
The adult stem cells are undifferentiated cell found within the tissue of a differentiated organ or tissue such as the brain, gut, lung, liver and bone marrow (Giordano & Galderisi 2009). Unlike embryonic stem cells, adult stem cells are not totipotent but are however pluripotent. They therefore possess extensive differentiation potential but are more restricted in their developmental potential compared to embryonic cells. Some adult stem cells are organ specific which made researchers to initially consider all adult stem cells to have differentiation capabilities limited to their tissue of origin (Giordano & Galderisi 2009:122). However recent studies have shown that adult stem cells can differentiate into cells of different types of cells. Adult stem cells are responsible for replenishment of damaged and lost cells in the organs they are found in.
The hematopoietic stem cells found in the bone marrow are the most studied adult stem cells. They were also the first stem cells to be used for clinical purposes in 1968. These stem cells are also the most widely used clinically and the least controversial. They are used for numerous hematological and immune diseases. Unlike embryonic stem cells, adult stem cells are harvested from a patient without ethical controversies. Since they are gotten from the patient being treated, they represent the least chances of being rejected by the patient's immune system during therapy as the patient recognizes them as self.
Adult stem cells have been used in the treatment of diseases for many years. Bone marrow transplantation has been used for treatment of various forms of cancer (Panno, 2005). As research progresses, the potential areas of applications are expected to grow. Scientist has been testing with animals the applicability of neural stem cell treatment for diseases such as Alzheimer's disease, Parkinson's disease and epilepsy. In the case of diabetes the use of adult stem cells as precursors for islet cells and embryonic stem cells capable of producing insulin is giving hope to millions of people around the world who are living with diabetes. Experiments have also demonstrated the potential of both adult and embryonic stem cells in replacing damaged heart tissues and establishing new blood vessels to the heart. This is going to give hope to millions of people who are suffering with heart related illnesses (Congress 2011). Although these experiments are in the initial stages in human beings, researchers hope to duplicate the same results attained in animals in humans. Treatment in many of these diseases is being tested. A lot of questions remain unanswered on the potential of stem cells in curing diseases in human beings.
Adult stem cells treatment has been on use. However human embryonic stem cells treatment is a new phenomenon in treating human beings. A lot of experimentation has been going on with animals. The potential it holds, going by the animal tests, is enormous. Future studies in human beings will help in formulating cell-based therapies for certain diseases. This is with the understanding that the demand for organs and tissues to be used in transplantation exceeds the amount available. Hence the development of specialized cells is expected to cover the difference. It will however be a question of time before medical professionals and the general public gets answers to these questions.
Before commencing cell-based therapies for treatment of diseases, scientists should be able to differentiate, transplant, and engraft the human embryonic stem cells properly. Each cell must be proven for its ability to proliferate efficiently into large quantities of tissue, ability to differentiate into the cell it is replacing and its ability to survive within the patient once transplanted and throughout the lifespan of the patient. Last but not least the transplanted cells must not harm the patient receiving the treatment.
Other than the treatment for chronic diseases, the human embryonic stem cell studies will enhance understanding of human development and in the testing of new drugs. By understanding the finer details of human development cells scientists hope to find treatment for chronic diseases such as cancer and birth defects that are caused by abnormal cell division and differentiation (Robin, 2007).The human embryonic cells will also be useful in testing new drugs. In the same manner cell lines are used to test anti-tumor drugs, pluripotent embryonic cell lines can be used to test drugs in vitro prior to using them in vivo. The stem cells in this case would differentiate into a desired specialized cell type and the drug would be tested on the differentiated cell for toxicity and efficacy.
The use of stem cells has raised heated public debate equivalent to abortion debates. Ethical and social issues has been raised especially the use of stem cells from embryos and fetuses (Novak, 2007). Proponents of stem cell research argue that the science is at a very early stage yet it is showing a lot of promise in being able to combat chronic diseases and disabilities. They argue that science that is promising to save millions of lives that are lost every year through cancer, diabetes, cardiovascular diseases, neurological diseases and others. There is a hope that one day, stem cell therapy will have advanced so much that it would be able to repair cells damaged through accidents and to correct genetic problems resulting from chromosomal abnormalities.
Opponents of embryonic stem cell research maintain that life is formed every time the egg is fertilized by the sperm and as such the embryo is potentially a human being who should not be destroyed (Shannon, 2001). They vehemently oppose the creation of human embryo and their subsequent destruction for medical research terming it as ethically and morally unacceptable. To counter this argument, proponents of embryonic stem research argue that while the embryo is potentially endowed with human life, it can nevertheless be equated to a human being until it has been implanted successfully into a uterus.
In vitro fertilization clinics on most cases create more human embryo from which a couple is to choose from. The excess embryos are often discarded. Proponents of embryonic argue that it is morally acceptable, with the consent of the couple involved to use the remaining embryo for potentially life-saving biomedical research (Rickard, 2002). Some opponents of embryonic stem cell research has argue that the benefits that are taunted to come from embryonic stem cell research can be achieved through adult stem cell research hence the embryonic stem cell research is not justified. Many of the scientists involved in embryonic stem cells dispute this citing the limitations of adult stem cells and the strengths of embryonic stem cells. Being that the embryonic stem cells are obtained from the inner cell mass of a blastocyst derived from a fertilized egg, the embryo must be destroyed for the embryonic stem cells to be obtained (Rickard, 2002). The stem cell debate therefore rotate around three important questions: Is the medical benefit of destroying a human embryo more valued than the potential life of the embryo? Are there alternative sources of embryonic cells that do not destroy an embryo? Can adult stem cells medically substitute embryonic cells?
The question of morality is not a straight forward one; on one hand, there is the need to alleviate suffering to millions of people who are suffering from debilitating diseases and on the other hand respect for human life. The million dollar question is whether it is more important to alleviate current human suffering by promoting embryonic stem cell research or it is more important to respect and thereby desist from destroying potential human life (Rickard, 2002). The moral question is based on the question of when does personhood begin; is it at conception or is it after implantation takes place in the womb. Biologically speaking an embryo is not a recognizable human being but rather a mass of dividing cells. After fertilization the egg develops into a zygote that grows into a blastocyst, a collection of undifferentiated tissue. The inner cell mass of a blastocyst develop into an embryo. It is not until two weeks after conception that the embryo attaches itself to the uterine wall. Some argue that the embryo is potentially a human being while another school of thought led by Thomas Shannon (2001) argues that potency is not an act. The embryo is therefore potentially a human being but not an actual human being.
On when life starts there are four schools of thought. The first school of thought belonging to conservative Protestant Christians assumes life begins at the moment the egg and the sperm unite to form a zygote. Proponents of this view do not support human embryonic stem cells research of any kind since life would be destroyed at any stage. The second school of thought is supported by the Catholics. It holds that life begins when the embryo attaches itself to the uterine wall. This takes place between the sixth and the seventh day (Shannon, 2001). However being that the blastocyst is formed on the fifth day and implanted on the seventh day, the Catholics argue against embryonic stem cell research because the two events are too close to each other. The third school of thought holds that personhood begins when the primitive streak is formed. This happens two weeks after fertilization. Such people do not have a problem with embryonic stem cell research as far as it happens within the first two weeks after conception. The fourth school of thought subscribe to the idea that personhood begins after birth. This is the most liberal school of thought and the most open to embryonic stem cell research (Erickson, 2007).
The four main religions in the world, that is, Christianity, Judaism, Hinduism and Islam, show remarkable difference when it comes to the issue of stem cell research. They all however lean towards lessening human suffering meaning they all support stem cell research albeit with minor differences on the extent. The Roman Catholic holds the most conservative views accepting stem cell research under particular conditions. The Roman Catholic church supports stem cell research as far as the stem cells used were not gotten through destruction of a human embryo. According to James LeGry, the Head of the U.S Conference of Catholic Bishops, the church accepts stem cell research conducted on adult stem cells, umbilical cord blood cells, and stem cells from miscarriages (Erickson, 2007). His assertion was supported by the Pope Benedict XVI (Sweeney, 2005).
The Islamic faith endorses stem cell research. Weckerly on his article tittled "The Islamic View on Stem Cell Research" states that the Qur'an in Chapter 23 and verses 12to 14 implies that personhood starts after the embryo develops into a fetus. This happens after the fourth month of pregnancy. The Hindus do not specify when life begins with certainty but has nevertheless not opposed the use of stem cell research if it is for the betterment of the human race. India, the birthplace of Hindu and the country with the largest Hindu population is not opposed to stem cell research. Judaism view personhood as starting when the embryo forms a fetus usually after the fortieth day. They are therefore not opposed to stem cell research. Buddhism is the only religion that is entirely opposed to embryonic stem cell research by insisting that life starts at conception (Erickson, 2007).
On August 9, 2001, President George W. Bush signed an executive order that limited the use of federal funds for research using stem cells. For a research to qualify for federal funds, it had to meet the following conditions: The cell derivation process was initiated before the day the executive order came into force; The cells were derived from an embryo that was created for reproductive purposes and was no longer needed; Informed consent was obtained for the donation of the embryo without involving any financial inducements. In 2006, Bush excercised his presidential veto when he refused to allow The Stem Cell Enhancement Act of 2005 to become federal law. The bill sought to legalize federal support for embryonic stem cell research that used fertilized eggs donated from in vitro fertilization clincs. In 2009 President Obama signed an executive order aimed at overturning former President Bush's 2001 order limiting federal funding for stem cell research. Obama's order allowed unconditional federal funding for embryonic stem cell research.
The use of embryonic stem cells in research has been clouded with a lot of controversies. It is viewed as killing a human being by Christian conservatives who believe life starts at conception and as far as the sperm has fertilized an egg successfully, the embryo formed is a human being with a right to life which should not be sacrificed at the altar of science. Congress passed the Dewey Amendment which bans use of federal money to finance embryonic stem cell research. President Bush in 2001 signed an executive order banning federal funding for any embryonic stem cell research that did not exist by then meaning federal funding would not be used for any new research on embryonic stem cells (Harris, 2010). In March 2009 President Obama signed an Executive Order reversing the earlier one by President Bush (Nasaw, 2009). Christian organizations went to court contesting that the executive order was a violation of federal law. The court upheld that indeed President Obama's executive order contradicted the Dewey Amendment and overturned it. The issue will remain controversial in the foreseeable future. None of the opposing sides is likely to give ground. Many a times however, people argue along ideological lines rather than on scientific facts.