Running Head: STEM CELL RESEARCH 1

Transcription

1 Running Head: STEM CELL RESEARCH 1 Stem Cell Research: Avoiding Controversies and Implementing Advances John Lin Hollidaysburg Area Senior High School Mrs. Haslam December 4, 2012

2 STEM CELL RESEARCH 2 Stem cells are premature cells that have the potential to build and repair any one of [the human] body s 200 cell types (Dyer, 2001, 4). They offer humans the power of regeneration, and they might cure people of fatal diseases. The discovery of this panacea seems like a gift from God, but a treasure so powerful does come with a cost. Controversial debates on the ethics of stem cell research are occurring all over the United States and even across the world. Humans have divided themselves between those that support the use of stem cells and those that oppose it. The concerns over the use and study of stem cells have also inhibited the progression of stem cell research and medical advancements. Despite this quandary, scientists are able to surmount this obstacle with a special type of stem cell called the Induced Pluripotent stem cells (ips cells). Maybe through this loophole, researchers can uncover an ultimate cure that will avoid the current controversial dilemma. Before discussing how the specialized ips cells might mitigate the discord on stem cell research, people must answer one question: What are the controversial issues revolving around stem cell research? The public has to understand the differences among specific types of stem cells and their functions. The various types of stem cells are categorized based on their potency or their differentiation ability. Stem cells are split into two groups: embryonic stem cells and adult stem cells. Embryonic stem cells develop throughout a zygote a diploid cell formed once an egg is fertilized by a sperm after five days of cell division (Stem, 2009, 5). During the early stages of the embryo, the embryonic stem cells are stable and retain their ability to transform into any type of cell. However, the transforming potential of these pluripotent embryonic stem cells are only temporary because the embryo is constantly growing, modifying its cells into specific parts of a baby. For example, as different stem cell nuclei express their genes in the zygote, the embryonic stem cells begin to transform into cells with specific functions. Some may form the

3 STEM CELL RESEARCH 3 ears of the baby, while others can form the hands and feet. Once the embryo matures, the stem cells are not considered embryonic, but adult stem cells. Adult stem cells are dispersed throughout a human s body; they are found in the skin, brain, bone marrow, and blood (Dyer, 2001, 9). They differ from embryonic stem cells in their conversion ability. These multipotent stem cells are restricted and can only alter into cells that border them. For instance, skin stem cells can only change into skin cells and cardiovascular stem cells can only form heart tissues. In addition to their limited changing ability, adult stem cells can be very difficult to find among surrounding cells (Stem, 2009, 8). Unlike embryonic stem cells that constitute the entire embryo, adult stem cells live around millions of specialized cells that already have a particular function. Spotting these unspecialized stem cells is like looking for a needle in a hay stack. Furthermore, even if they are located, the adult stem cells are hard to extract. They generally don t exist in large quantities because they are mostly surrounded by normal cells. Therefore, harvesting adult stem cells can be tedious, and some procedures of extraction, like the removal of stem cells from bone marrow, can be extremely agonizing (1985, 2009, 7). Nevertheless, even though adult stem cells possess a plethora of problems, the main controversies revolve primarily around embryonic stem cells. To conduct research on embryonic stem cells, precious embryos are donated and destroyed. The elimination of stem cells that have the potential to become a living human troubles millions of people around the world. They believe the research removes a human s right to life; it makes the decision of to be or not to be for thousands of powerless individuals. In the medical field, the [necessity] of embryo destruction also contradicts one of the cardinal rules of medical ethics: Primum non nocere (First, do not harm) (Zacharias, Nelson, Mueller, & Hook, 2011, 3). However, scientists have argued against this point. Even though the study of

4 STEM CELL RESEARCH 4 these cells destroys potential life, some believe the killing of embryos can be justified because it benefits existing humans (Gavaghan, 2001, 11). To support this belief, Gavaghan (2001) used Dr. Daniel Wilker, an ethicist, to assert that most embryos cannot be labeled as living unless they are implanted in a woman s uterus. Wilker also states how most couples decide to dispose their fertilized zygotes through abortion before considering donating them to science. In the end, whether stem cells profit science or are wasted by personal choice, they are eventually destroyed. The controversy of stem cell research has reached an international level. In several countries, such as Ireland, Italy, Germany, Poland, and Austria, stem cell research are restricted, while other countries, like Belgium, United Kingdom, Sweden, Switzerland, and Korea, allow study of stem cells (Zacharias et al., 2011, 3). In the United States, the issue was inconclusive until President George W. Bush came to a decision that embryonic stem cells are excluded from federal funding while adult stem cells are not (Stem, 2009, 1). In other words, the embryonic stem cells cannot access the support from government finance, but private foundations can still sponsor its research. After this proclamation, scientists encountered several new problems in stem cell development. Without sufficient embryonic stem cells, which are known as the golden standard of stem cell research, researchers are isolated from important cellular information. Investigators will lose significant stem cell lines that bridge them with existing knowledge; the loss of these cell cultures will inhibit further scientific progress. For instance, in Bush s address, the governmental funding of embryonic stem cells resulted in only sixty stem cell lines or, in other words, sixty different cell cultures that are studied for remedial features (Stem, 2009, 2). Compared to other countries, which utilize thousands of stem cell lines for research, America might be falling behind on its scientific studies.

5 STEM CELL RESEARCH 5 The discovery of ips cells might provide an avenue for broadening the exploration of stem cells and fulfilling stem cells potential in the medical field. It is like the hybrid between embryonic and adult stem cells. To put it simply, ips cells contain the roots of an adult stem cell, but boast the unlimited altering ability of embryonic stem cells. In 2008, a research team at the University of Southern California Los Angeles, led by Kathrin Plath and William Lowry, used genetic alteration to turn back the clock on human skin cells and created cells that are nearly identical to human embryonic stem cells (Regenerative, 2008, 2). Plath, an assistant professor of biological chemistry, said [their] reprogrammed human skin cells were virtually indistinguishable from human embryonic stem cells (Regenerative, 2008, 4). The discovery of the ips cell is an addition to the other experiments conducted around the world, such as the research led by the director of ips cell research at Kyoto University in Japan, Shinya Yamanaka. The method used is similar to a type of bacterial gene transfer called transduction, which helps bacteria diversify their gene pool since they are adding new genes into their bodies through mutation or the transfer of DNA. Through transduction, a virus infects a bacterium and breaks it down by inserting its genetic information. Resulting from the remains are more viruses that carry their parent s deadly genes, but one virus may carry the genes of the bacterium, which are harmless. Going through another transduction process on a different bacterium, the non-hazardous virus will insert its bacterial gene. Eventually, the virus infuses the DNA from a previous bacterium into a new bacterium. From this natural phenomenon of transduction, the UCLA scientists added specific genes from embryonic stem cells into any adult stem cells (skin, brain, or blood stem cell) and induced them to express pluripotent features.

6 STEM CELL RESEARCH 6 New beneficial possibilities may also unfold with the discovery of ips cells. Because ips cells originate as cells that do not have the potential of giving a new life, they dodge many controversial concerns. A stem cell s right to life is no longer an issue, and embryos are also preserved. Another problem ips cells eliminate is the chance of immune rejection (Zacharias et al., 2011, 21). People who have malfunctioning organs, such as liver failure or a weak heart, may need an organ transplant. Finding a suitable donor is extremely unlikely in most cases. Where would a patient find someone who would donate to them a healthy heart? Plus, even if the sick individual finds a donor, his or her body s immune system will most likely reject the transplanted organ. The immune system will recognize the organ as a foreign entity and will continually attack it. Therefore, for the rest of the patient s life, he or she will live on prescribed medicine to suppress the immune system s assault. Using ips cells, scientists can create new cells that coexist with the patient s body. It can eliminate the possibility of rejection because the ips cells are made from the patient s tissues. Furthermore, the process of extracting ips cells from the patient is painless. Doctors only need a small sample of skin tissue to produce an unlimited supply of ips cells (Zacharias et al., 2011, 21). Aside from these general perks, ips cells also have the potential to cure terminal diseases that may disturb various parts of the human body, such as the heart, brain, and muscle movements. As the most vital organ within the human body, a heart pumps blood to various parts of the body, providing oxygen for tissues to function at an optimal level. However, if starved for oxygen, heart cells die, which are not replaced (Carmichael, 2005, 1). Since a human s body grows throughout their early years and stabilizes at a fixed size, a heart with only parts of it functioning may not fully support the demand the body needs. The heart may be an amazing muscle that has immense strength, but the loss of heart tissues creates burdens on its remaining

7 STEM CELL RESEARCH 7 parts. As a result, the heart muscle will over work itself and wear away more quickly, which may lead to premature deaths in normally healthy adults. On another note, heart attacks are common, especially in America since fast food chains have changed the diet of many. Nevertheless, through the incorporation of stem cells, there may be hope left for those enduring heart problems. According to Donald Orlic, a molecular biologist from the National Human Genome Research, stem cells can become substitute heart tissues. In his studies, he injected [mice] with bone marrow, which contain a plenitude of stem cells, and found the stem cells to be repairing the injured heart muscle (Carmichael, 2005, 4). Using this discovery and combining it with the breakthrough of ips stem cells, scientists may eventually eradicate countless heart problems that vex humanity today. Second to the heart, a human s brain also proves vital for human survival. After years of study, psychologists have only unveiled a miniscule part of the mysterious functions within the brain; however, they did find out that a person s consciousness resides within their brain, and the brain defines the unique character of each individual. Without the brain, humans lose their most valuable advantage within the animal world and forfeit the vast, untapped knowledge of the universe. Several brain diseases trouble humankind today, such as Alzheimer s, Autism, strokes, and seizures. But medical science has advanced through the years and developed methods to improve brain functions in particular brain disorders, such as Parkinson s disease. Parkinson s disease attacks one s central nervous system by breaking down their dopamine-producing neurons (Murphy, 2001, 2). Consequently, the loss of dopamine causes patients to develop motor dysfunctions that may lead to shaking hands, awkward gaits, and other muscle strains. These symptoms usually appear on people over middle age, so Parkinson s concerns many of the older generation. Without control of their bodies, many patients will deal

8 STEM CELL RESEARCH 8 with mental stress, depression, and even dementia as time progresses. Luckily, in the past century, researchers at Harvard Medical School have found pioneering breakthroughs. According to their findings in rodents, embryonic stem cells can differentiate into the required dopamineproducing cells (Murphy, 2001, 5). Although the requirements here specifically ask for embryonic stem cells, scientists may combine the use of ips cells to tackle Parkinson s and other brain diseases that impair humans. Through this method, the ethical concerns will disappear while the benefits for patients suffering incurable diseases will emerge. Afflicted seniors may regain their lives and enjoy their last fifty years without biological disorders that may have stripped away their mental and physical capabilities. Lastly the amazing powers of ips cells can also be used to assist those who have problems with muscle movement. In addition to brain failures such as Parkinson s people may also lose their muscle movements through malfunctions in their peripheral nervous system (everything but the brain and spine). Some diseases include Hereditary Spastic Paraplegia (HSP) and Kennedy s Disease, but the most well-known is Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig s disease. Most American baseball fans remember Lou Gehrig as The Iron Horse of Major League Baseball in the 1940s because of his endurance and dexterity. However, despite his active life as a competitive player, Gehrig s athleticism was shortened by the diagnosis of amyotrophic lateral sclerosis (ALS), a disease that causes the motor neurons in a human body to atrophy. In other words, Gehrig s muscles began to deteriorate that eventually prompted his lung muscles to stop functioning and suffocate him. If Gehrig had today s medicine, he may not have died, for ips cells might have provided a cure for his disease. Dr. Kevin Eggan, the chief scientific officer of The New York Stem Cell Foundation, enlightened the world when he and his

9 STEM CELL RESEARCH 9 team began experimenting with effects of ips cells on organisms with ALS. He induced [adult cells] to become motor neuron cells similar to the cells affected by [ALS] (New, 2008, 5). In other words, he created healthy replacements of the dysfunctional motor neurons. Although testing the efficiency of these cells in humans isn t attempted yet, Eggan s work shows promise for future ALS patients to regain their muscle movement. ips cells open a new outlook in medicine and provide the means to transcend current stem cell applications, for once scientists discover how to effectively employ them in health care, sicknesses ranging from mild colds to severe diseases may entirely vanish. However, current ips technology is far from perfect, for tumorigenesis formation of tumors is highly likely to occur (Zacharias et al, 2011, 19). According to Dr. Eggan s research, the genes that stimulate the transformation of adult stem cells to its pluripotent stage include a cancer-promoting gene (New, 2008, 5). Unless such threats are removed, ips cells will remain under study and away from human use. Therefore, any thoughts of therapeutic implementation on humans will be contingent on future discoveries and developments. Despite the drawbacks ips cells possess, it is still one of the greatest advancements in stem cell research because it evades several controversial issues. The potentials it retains are unimaginable, but to unlock these capabilities, research on embryonic stem cells is still needed. Once researchers have a better understanding on the matter, Shinya Yamanaka predicts that ips cells will eventually replace [embryonic stem cells] in most, if not all applications in the future (Zacharias et al, 2011, 23). Nevertheless, seeing how stem cell research is still at the inception of its studies, time is needed to see how it will influence the future. The breakthrough on ips cells provides the world with a unique insight on the possibility of stem cells research. Its standards might become the paramount in medicine, rendering humans almost invincible in

10 STEM CELL RESEARCH 10 terms of health. Scientists expect ips cells will eventually create similar cells for the study of any number of diseases, from Parkinson s disease to diabetes and cancer (New, 2008, 7). Thus, solving ips cell s enigmatic puzzle will most likely lead to the eradication of a myriad of threatening health concerns.

11 STEM CELL RESEARCH 11 References 1985: Saving Lives With Marrow Transplants. (2009). 1985: Saving Lives With Marrow Transplants. World Book Publishing. Retrieved December 3, 2012, from Carmichael, M. (2005). Rebuilding the Heart. Newsweek, 146(14), 76-84, Retrieved December 3, 2012, from Dyer, Nicole (2001, November 12). Stem cells: The next cure?. Science World, (5), 14. Retrieved December 3, 2012, from Gavaghan, Helen (2001, January 01). The promise of stem cells. World Health Organization, (12), 800. Retrieved December 3, 2012, from Murphy, M. (2001). Stem cells proffer promise for Parkinson s. Chemistry and Industry, (5), 133. Retrieved December 3, 2012, from New York Stem Cell Foundation; NY Stem Cell Foundation plays critical funding role in major new ALS research announced. (2008, August 18). Stem Cell Week, 89. Retrieved December 3, 2012, from Regenerative Medicine; UCLA stem cell scientists reprogram human skin cells into embryonic stem cells. (2008, March 01). Obesity, Fitness & Wellness Week, Retrieved December 3, 2012, from Stem Cells: Seeds of Hope. (2009). Stem Cells: Seeds of Hope. World Book Publishing. Retrieved December 3, 2012, from Zacharias, D., Nelson, T., Mueller, P., Hook, C. (2011, July 01). The Science and Ethics of Induced Pluripotency: What Will Become of Embryonic Stem Cells?. Mayo Clinic Proceedings, (7), 634. Retrieved December 3, 2012, from