The Possibility of Stem Cells
The advancements in recent medical procedures and cures have become something to truly admire. Most diseases can now be cured with a prescription; some problems can be fixed with a quick operation, and most of the really bad ones, like organ failure, can be cure with an organ transplant. There are of course limitations to these types of solutions. With some diseases, the simple cure cannot fix damage that has already been done. In the cases that require an organ transplant there needs to be an organ donor, unfortunately these organs are not always a match and many patients never receive an organ. However, if we were to focus more time and effort into research on Stem Cells the discoveries that we find could solve many of the problems in the medical field. By making Stem Cell research more of a priority we could help us cure diseases such as cardiovascular diseases and other complications, repair damage done to a person’s spinal cord, and solve problems that occur when trying to transplant a donated organ.
To begin with, there are two different kinds of stem cells when people talk about stem cell research, embryonic and adult. Embryonic stem cells are obtained from eggs that have been fertilized “in an in vitro fertilization clinic – and then donated for research purposes with informed consent of the donor. They are not derived from eggs fertilized in a woman’s body” (NIH). With these stem cells, scientists can attempt to generate more by growing them in a laboratory. Although this process is sometimes inefficient, if the cells do survive and multiply, they multiply in vast amounts with plenty of stem cells that can be used for research or “frozen and shipped to other laboratories for further culture and experimentation” (NIH). With this the researchers can manipulate the chemical environment so that the embryonic stem cell differentiates and become another type of cell that can be studied. They can form into cell types such as muscle, nervous, blood, and many more. However after the cells or culture of cells have been taken, they will only last for about six months without differentiating, so these stem cells tend to be valuable while they have them (NIH). Adult stem cells tend to be a little different. They can be taken from anyone, from children to fully grown adults, and tend to be found among differentiated cells of a particular tissue or organ that it specialized in. “The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found” (NIH). These cells are located in many different parts of the body and each one is focused at making differentiated cells to repair that particular tissue or organ. Although scientists found out that if any of these stem cells are removed and placed in a lab, their ability to divide is limited. Meaning that adult stem cells simply do not grow as well in a laboratory as the embryonic stem cells (NIH).
There are several medical problems and diseases that could be cured if scientists were to focus more effort into stem cell research. One disease that is currently one of the biggest problems in the US is cardiovascular disease. In the article, Current Stem Cell Delivery Methods for Myocardial Repair, the author Calvin Sheng says that “Cardiovascular diseases (CVDs) are the number one cause of mortality worldwide, and their prevalence is projected to remain the single leading cause of death”. Currently, the only treatment for heart failure caused by cardiovascular diseases is a heart transplant. With limited donors and an even smaller amount being an organic match to the recipient, many patients of heart failure do not receive a heart. Therefore, researchers have started looking into ways to restore the hearts function by using stem cell therapy. The theory is that by introducing certain cells to the damaged or around the damaged area of the heart, the cells will be able to repair the damage. In the research that has already taken place, researchers have discovered that there are multiple cells required to accomplish such a repair. One type of cell cannot fix everything, however it does seem to cause some positive results. For example, in the article titled Regenerative Medicine For The Treatment Of Heart Disease, written by E.M. Hansson and U. Lendahl, they mention that during an experiment involving the injured hearts of rabbits and sheep, researchers grafted skeletal muscle cells to the injured areas. Although the graft was successful there was a significant problem, the skeletal muscle that had been grafted to the Cardiac muscle did not magically turn into cardiac cells, nor did it improve the cardiac function but rather increased the instances of an irregular heartbeat. Because of this, these researchers discovered “that cells lacking a documented cardiac potential cannot be expected to differentiate to cardiomyocytes” (Hansson). Even though they were not successful with a cell type as abundant as skeletal muscle, there has been more success when using bone marrow-derived cells. Hansson and Lendahl’s article also mentions that, “To date, more than 1000 patients have been treated with non-cardiac cells, particularly bone marrow-derived cells, for various cardiac conditions”. Some clinical trials that show cellular therapy as the treatment for cardiovascular disease have shown varied results all along the spectrum of success, from a strong improvement to damaged tissue, to no signs of any positive effect in the affected area. REPAIR-AMI and STAR-heart, two of the more significant studies showed about a 3% improvement to damaged tissue function. (Hansson). After looking at these results it is clear that bone marrow stem cells have a much more positive effect than skeletal muscle cells previously mentioned. However the bone marrow stem cells still seem to be lacking the ability to transdifferentiate to cardiomyocytes, because of this scientists are not sure why bone marrow stem cells have the positive effect that they do. This shows that further research and experimenting needs to be do in order to better understand how we can achieve our desired medical goals.
Another medical problem that scientists hope to be able to cure using stem cells research is nervous system or spinal cord damage. In the article titled Neural Stem Cells And Regeneration of Injured Spinal Cord, the author Hideyuki Okano mentions that there are two major strategies used when attempting to repair the spinal cord; the first is the “activation of endogenous neural stem cells”, and the second method is “cell transplantation therapies”. The difficult thing about trying to regenerate the spinal cord and repair injury is that although there are stem cells present, they do not naturally repair any damage done. This is why spinal injuries are usually so damaging; any injury directly done to the spinal cord could cause permanent damage. “In other words, although endogenous neural stem cells are present in the spinal cord and they do proliferate after a spinal cord injury, almost all of them differentiate into astroglia, not into neurons or oligodendroglia, which are myelin-forming cells” (Okano). However is past experiments, when transplanted into the hippocampus portion of the central nervous system, the neural stem cells did cause neurogenesis. After further examination, researchers noticed that after damage to the spinal cord occurred, the body responded with inflammation, sending a variety of proinflammatory cytokines to the injured area. This inflammatory response causes the cells (including stem cells) to differentiate into astroglia cells, which would prevent the desired result of neurogenesis. Although they discovered that a single dose of anti-inflammatories did not improve injury, due to the short half-life of the specific drug, they believe that constant monitoring and doses of the anti-inflammatory drug over a longer period of time than was experimented with could cause more positive and noticeable results. They also discovered that the amount of time that passed between the injury and the stem cell therapy was a huge factor when it came to recovery (Okano). Although there are many factors limiting the success of this research there has been some progress and a small amount of success made so far, and given insight on new techniques that may be possible in the future (Okano).
A different branch of research that uses stem cells as a main focus is organ manufacturing or organ cloning. A rather large issue in the medical field that continues to be a problem is finding organ donors that match a specific patient. If an organ is not a good enough match, the patient’s body will begin to reject the transplanted organ. This means that the patient’s immune system begins to attack the new organ, causing the organ to fail and eventually die. In the early 2000’s, there was a discussion concerning human cloning for tissue transplantation purposes. In the article, Transplantation: Biomedical And Ethical Concerns Raised By The Cloning And Stem-Cell Debate, written by Gayle E. Wolosehak, the author mentions that although experiments with animal cloning has been moderately successful in the past, “In general, cloning has not been shown to be safe… Most of the cloned animals develop premature aging syndromes with neurological disorders and shorter life spans”. Therefore human cloning would have similar results. Besides the complications of cloning there are the ethical and moral problems with “a subclass of human beings (or perhaps just “subhumans”) who would not have choices about whether they wanted to give up their organs for transplantation or not” (Woloschak). However there have been attempts at manufacturing human organs separately. As it turns out, trying to create a complex organ such as a liver, heart, or kidney is more complicated than it sounds. Organs usually have more than one cell type that allow it to grow and properly function. Xiaohong Wang, the author of the article, Intelligent Freeform Manufacturing Of Complex Organs, mentions that “A complex organ rely upon the organ’s constituent cell types, soluble biological components, extracellular matrices (ECMs), and overall organization. Cell–cell, cell–matrix, and cell–signal interactions are essential for the morphogenesis and functional differentiation of most cells/tissues/organs” (Wang). Such complex organs cannot be simply grown in a petri dish. As of 2012, researchers created a machine that uses a technique called four-nozzle low-temperature deposition manufacturing (FLDM) to create complex organs such as a liver. This machine and technique has been able to achieve manufacturing of complex organs by controlling many of the elements needed to be successful. Such as “(i) hierarchical organization of multiple population of cells and growth factor gradient changes in a more intricate physiological geometry; (ii) simultaneous deposition of one scaffold material, one parenchymal cell, and a vascular system with two main cell types in a more elegant native tissuespecific phenotype; (iii) computer definition of fluid paths and macro/microstructures in a more patientspecific manner; and (iv) spatial distribution of multitissue boundaries and fluorescent biomarkers in a more controllable pattern” (Wang). The hopes in furthering this research is that they will develop a technique that will allow for manufactured or cloned organs to be used for clinical purposes as a fast, easy, and more reliable way than our current organ donor system.
One main issue that surrounds and hinders the advancement of stem cell research is that in many areas of the research, the experiments require the use of embryonic stem cells, which can only be obtained from embryos. In nearly every case when the stem cells are obtained, the embryo does not survive. This is where the controversy of stem cell research is centered; the fact that it is considered nearly the same as abortion. However in my research I discovered that this is not entirely true. As was stated in an earlier paragraph, embryos are only obtained from the excess eggs used for vitro fertilization. The fertilized eggs that are not used for implantation, will normally be discarded and destroyed (Robertson). Instead of simply discarding the embryos, researchers take the valuable stem cells. These scientists are “not… creating embryos solely for research” (Robertson), they are simply not allowing these embryos that would normally have been thrown away to go to waste.
Stem Cell Research is not some mysterious and evil field of science bent on conducting dark experiments for the greater good. The scientists take what is left over, being thrown away, or donated in an attempt to help save lives. If scientists focused their efforts into Stem Cell Research, current problems such as diseases and the lack of organ donors for patients could be fixed. They could reduce the number of people dying from cardiovascular diseases. They could heal a person’s injured spinal cord. And the wait for a matching organ donor for a patient would no longer be a problem. This is why I believe that Stem Cell Research should become more practiced field of research.
Hansson, E. M., and U. Lendahl. “Regenerative Medicine For The Treatment Of Heart Disease.” Journal Of Internal Medicine 273.3 (2013): 235-245. Academic Search Premier. Web. 28 Mar. 2016.
Okano, Hideyuki, et al. “Neural Stem Cells And Regeneration Of Injured Spinal Cord.” Kidney International 68.5 (2005): 1927-1931. Academic Search Premier. Web. 29 Apr. 2016.
Robertson, John A. “Embryo Stem Cell Research: Ten Years Of Controversy.” Journal Of Law, Medicine & Ethics 38.2 (2010): 191-203. Academic Search Premier. Web. 29 Apr. 2016.
Sheng, Calvin C., Zhou Li, and Hao Jijun. “Current Stem Cell Delivery Methods For Myocardial Repair.” Biomed Research International (2013): 1-15. Academic Search Premier. Web. 28 Mar. 2016.
“Stem Cell Basics.” National Institutes of Health. U.S. Department of Health & Human Services, 17 June 2015. Web. 28 Apr. 2016
Wang, Xiaohong. “Intelligent Freeform Manufacturing Of Complex Organs.” Artificial Organs 36.11 (2012): 951-961. Academic Search Premier. Web. 28 Mar. 2016.
Wolosehak, Gayle E. “Transplantation: Biomedical And Ethical Concerns Raised By The Cloning And Stem-Cell Debate.” Zygon: Journal Of Religion & Science 38.3 (2003): 699. Academic Search Premier. Web. 6 Apr. 2016.