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Show Hingkley Journal of Politics 2006 Researchers derive embryonic germ (EG) cells from aborted human embryos or fetuses. These EG cells are extracted from a five to nine week old aborted human embryo or fetus. Scientists at Johns Hopkins University made the first successful extraction of stem cells from an aborted fetus in 1998 (Johns Hopkins University, 2002). EG cells are demonstrating more potential to differentiate than scientists originally believed. Adult stem cells are found among the already specialized cells of each tissue or organ in the body. Pluripotent, multi-potent, and progenitor stem cells are all found in adult stem cells. An adult stem cell must be capable of self-renewal for the lifetime of the organism. These cells function to replace and repair the tissue or organ where they are located (NIH, 2005c). Adult stem cells are rare: only an estimated one in ten thousand to fifteen thousand cells in the bone marrow is a blood-forming stem cell (NIH, 2005b). Adult stem cells are the least flexible type of stem cells, and their behavior varies greatly, depending on their local environment. Although scientists have engaged in adult stem cell research for more than forty years, it was not until recently that researchers acknowledged that adult stem cells could possibly generate other types of specialized cells than the environment in which they reside. Prior to this, researchers presumed that adult stem cells only had multipotent capabilities. Recent studies have shown that blood stem cells may be able to generate skeletal cells. The research to date demonstrates that adult stem cells may take on the characteristics of cells that have developed from the same primary germ layer or a different layer. Stem cells derived from bone marrow are capable of differentiating into another similarly derived tissue such as skeletal muscle (NIH, 2005b). Possibilities With a basic understanding of stem cells and the way they work, the possibilities that they present become apparent. According to leading researchers James Thomson of the University of Wisconsin and John Gearhart of Johns Hopkins University, stem cells could potentially be used for such things as: • Growing nerve cells to repair spinal injuries and restore function to paralyzed limbs. • Growing heart muscle cells to replace useless scar tissue after a heart attack. • Making brain cells that would secrete dopamine for the treatment and control of Parkinson's disease. • Growing cells that make insulin, creating a lifelong treatment for diabetes. 1 • Growing bone marrow to replace blood-forming organs i damaged by disease or radiation. . • Making blood cells genetically altered to resist specific dis- ease, such as HIV, and to replace diseased blood cells (CNN, 1998). i These treatments could be accomplished through various techniques. One method is grafting pluripotent and multipo- tent stem cells into a human body. Grafting is the process of growing stem cell lines to produce healthy cells. These cells replace damaged cells. Grafting also introduces the possibility of taking cells from stem cell lines and placing them in a coexistent condition with damaged cells, allowing them to repair those cells (UMCB, 2002, p. 10). As stated above, stem cell therapy could possibly make blood cells resistant to specific diseases, such as HIV or AIDS. Scientists could accomplish this through a treatment called gene therapy. Gene therapy is the genetic modification of cells to produce a therapeutic effect (NIH, 2005, Chap. 6). Stem cells could serve as vectors, or agents that transfer genetic material from cell to cell. In the case of creating cells resistant to HIV or AIDS, the genetically enhanced cells could act as healthy cells, making the HIV patient more resistant to infection and illness (UMCB, 2002, p.10). Stem cell research may also influence the way researchers test drugs. Scientists could test drugs for safety and performance on skin or heart cells before they reach the human test phase. Stem cell research promises to increase our understanding of human development (Nuffield Council, 2005). It is important to note that stem cell research cannot guarantee all of these medical miracles. While research has been promising and scientists are making breakthroughs, this does not assure that these initial efforts will become a reality. A great deal of time and money will be required before stem cell research produces beneficial therapies. Caution must be taken to avoid a slippery slope of unrealistic expectations. We cannot assume that stem cell research will result in life saving treatments in a short amount of time. That is why it is stem cell research, because scientists are still discovering what is possible. Thomson, who was the first scientist to derive stem cells from a human embryo states, "The real lasting contribution of human embryonic stem cell research may be increased knowledge of the human body, which could change human medicine ever more dramatically than new transplantation therapies" (Vergano, 2004). The Debate Along with possibilities, stem cell research carries with it a tremendous ethical dilemma for some parties. Embryonic stem cell research produces more controversy than the other sources of stem cells- embryonic germ cells and adult stem cells. This is due to several characteristics unique to embryonic stem cells. The debate over whether it is ethical to utilize embryonic stem cells relates to the method in which scientists obtain them. As explained above, researchers derive embryonic stem cells from the inner cell mass of a blastocyst-stage embryo. The process of extraction destroys the embryo. This destruction pushes stem cell research into the debate on the moral status of the embryo. The Coalition of Americans for Research Ethics (CARE) was founded by prestigious physicians, researchers, and bioethicists, and is perhaps the best example of a group 17 |
