Stem cells are cells that have not differentiated into a specific type of cell and can become any part of the body that is needed (Stem cells and diseases, 2009). There are three different ways for scientists and doctors to harvest stems cells to use in research and in current treatments. The most commonly used stem cells come from adult humans and are found within bone marrow. Stem cells are also found in the umbilical cord and are harvested and stored shortly after birth to be used in a national bank, similar to a blood bank. The most controversial and richest source of stem cells is human embryos, which generally come from unused fertilized eggs for in vitro fertilization. No matter what the source is, stem cell research can advance medical science beyond simple treatment of diseases and into cures for some of the most insidious illnesses.
Currently stem cells are harvested from the person’s bone marrow they are used to treat (Stem cells and diseases, 2009). Generally, these stem cells are used to rebuild the immune system and sometimes other organs which have been compromised or damaged by radiation or chemotherapy treatments, most commonly in bone marrow transplants for leukemia patients (Stem cell research, 2009). Since both treatments can reduce the effectiveness or completely destroy the immune system in patients, rebuilding immunity is crucial. When the immune system is compromised, simple illnesses like the common cold can kill a person, and using stem cells to speed the process of rebuilding immunity has saved many lives.
Umbilical stem cells have the same properties as adult stem cells and can only be used to treat specific conditions (Stem cell research, 2009). This is due to the fact that stem cells in a fully formed human can only create the cells they are programmed to create. If a person needs to have bone marrow replaced, it can only be replaced with bone marrow stem cells, which is the most successful use of stem cells to date. In 2007, James Thomson, through the University of Wisconsin, discovered a method to force adult and umbilical stem cells to behave as embryonic stem cells and create any cell needed, called Induced Pluripotent stem cells. This method is currently not used to treat human diseases due to the fact that the patient would be more likely to develop tumors and cancer cells from these mutated stem cells (Experiment Resources, 2008).
While still in the experimental stages, embryonic stem cells show the most promise to curing diseases in humans (Stem cell research, 2009). Since embryonic stem cells contain no preprogramming, scientists can use them to create any cell necessary for treatment. Previously incurable diseases such as Parkinson’s or Alzheimer’s could be cured in the future using embryonic stem cells (Stem cells and diseases, 2009). By using embryonic stem cells it may be possible to clone your heart or other organ to be used during a life saving transplant which would reduce the risk of rejection to almost zero percent. Cancer could become a disease only read about in history books if embryonic stem cells were used as treatment. With the use of embryonic stem cells, brain and spinal cord injuries could be treatable, and possibly even fully reversible.
Stem cell research may be controversial to some people and others may view it as unethical, but the benefits of stem cell research are clear. Even if stem cells can only do half of what scientists are theorizing, the benefits of the research far outweigh the ethical concerns. Even with what stem cells are able to currently treat, the research done so far has proven a great benefit to the advancement of medical science and the treatment of previously incurable diseases.
Filed Under: Medicine
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Stem Cell Research
March 7, 2010
Stem cells can be obtained from three different sources. The first and most controversial source is an embryonic cell that comes from a three to five day old blastocyst. A blastocyst is a ball of undifferentiated cells that forms after an ovum is fertilized. These are often created by in vitro fertilization for implantation in infertile woman or gestational carriers in order for these women to become pregnant. Some of the “extra” unused blastocysts are frozen for possible future use. These blastocysts and aborted fetuses have been used to create embryonic stem cell lines. The second very rich source of stem cells is the umbilical cord. Blood cells from the cord blood of a newborn infant can be used immediately or frozen for later use by that infant, close relative, or unrelated recipient. The third and most recently discovered source is adult stem cells, or induced pluripotent stem cells (iPS). Adult bone marrow or blood cells can be artificially induced back into unprogrammed cells and then can be used as stem cells to form other somatic cell lines, such as nerves and muscle cells.
The origin of the first argument is the source and process for producing some stem cells, specifically embryonic stem cells. Often, people jump to the conclusion that all stem cells are derived from embryos meaning that a human life must be sacrificed in order to create a stem cell line. Those people who feel that life begins at conception oppose the use of unused blastocysts and aborted fetuses in research, while pro-choice groups generally support embryonic cell studies advocating that new lives were not created just for the purpose of experimentation. In August 2001, President Bush compromised by approving federal funding for research that involved only the 15 already existing stem cell lines. Other cell lines could still be developed with state and private funding. According to various polls, the American public strongly supports federal funding for embryonic stem cell research – over 60% of Democrats and independents and 40% of Republicans. In March 2009, President Obama used an executive order to lift the eight year ban on federal funding to develop new stem cell lines. Potentially, one life could save millions of people from horrendous, unnecessary, tragic illnesses and untimely deaths.
Another controversy around stem cell use is the movement to create siblings who can serve as identical-matched donors. Umbilical cord blood is the typical tissue used in these situations, but occasionally supplemental bone marrow must be used. The use of in vitro fertilization and preimplantation genetic diagnosis has allowed parents to create compatible fetuses who do not have the sibling’s genetic disease. Some people have raised moral and religious objections to creating a horde of embryos that will just get discarded without a thought if they do not meet the right criteria to help the sick sibling. Should a family create a child just to help a sibling, or should they have a baby because the new child would also be special to them? The first reported identical-matched donor case was five year old Molly Nash with Fanconi’s anemia who received cord blood cells from her newborn brother, Adam. To date, 58 siblings have been created for this purpose. In February 2010, the American Academy of Pediatrics issued a policy statement that outlined strict criteria for using children as blood stem cell donors. The use of umbilical blood cells was not discouraged as long as the newborn infant was not placed at physical risk during delivery. The policy also addressed the psychological threats to both the donor and recipient children. The ongoing controversy over discarding unmatched embryos may be resolved by using the newly discovered adult stem cells.
The discovery of adult stem cells, or iPS, has excited the scientific community, but these cells still have their problems. An already differentiated body cell must be genetically reprogrammed back into an unprogrammed pluripotent cell that looks like an early embryo. The advantage is that an embryo does not have to be created, but the disadvantage is that cancer-causing oncogenes and retroviruses must be used to “unprogram” the adult cells. This could lead to an increased risk of cancer in already compromised patients. These cells could be used to treat a host of horrible human conditions from birth defects to heart disease and degenerative neurologic conditions. Scientists working in tissue engineering and regenerative medicine hope to someday use the cells from the intended recipient to create a new custom designed cell type or even a perfectly matched organ to replace damaged tissue.
With new knowledge comes a new concern about the creative misuse of this information. There are growing fears that stems cells would be used not only to clone new organs but could be used to clone whole new preferred populations. Some are concerned about the unintended consequences of new cancers or illnesses from retroviruses. Others argue that we should not mess with human life, and we should not be trying to play God. Research and medical organizations could allay the fears of the public by issuing policy statements similar to the one published by the American Academy of Pediatrics and by closely regulating the use of stem cell lines.
The potential social and economic benefits of the many that could be saved far outweigh the detriments of loss of life or limited funding. Adult and umbilical cells are emerging as the more advantageous sources with the fewest ethical controversies. Umbilical cells would be even more acceptable if genetic matches could be determined before an ovum is fertilized and an embryo is formed. That way an innocent life would not need to be sacrificed. It is essential that scientists zealously pursue stem cell research while valuing all life.