Of the 4,000 Americans waiting for heart transplants, only 2,500 will receive new hearts in the next year (Ossola). In America today, there is a major problem regarding organ transplants. Too many people are waiting for an organ that may never come, and those that do receive cadaver transplants still have to deal with the very real possibility of bodily rejection. Through the application of stem cell research however, we have the ability to overcome these obstacles and save the lives of countless humans. Stem cells are undifferentiated cells that are able to specialize into specific cell types. They can be used to for a variety of medical applications from treating cardiovascular and brain disease to organ and tissue regeneration. Researchers have shown some progress in tissue engineering of heart, liver, and kidney tissue in vitro using stem cells, however the transplantation of these engineered tissues in vivo will require further advances (Belair).
In my research, I will be specifically looking into the use of stem cells to generate lab grown organs for human transplants. The predominant organs of interest for transplant surgeons is heart, lung, liver, and kidney (Belair). This technology is on the forefront of modern medicine and I aim to prove the benefits of furthering research in this field. Tissue engineering has the ability to revolutionize the way we currently treat patients by eliminating the need for organ donor programs and creating organs that can be transplanted with very little chance of bodily rejection. Also, people commonly have perceived moral objections with stem cell research, often stemming from religion. I would like to address these arguments by informing of more modern methods of stem cell isolation.
Stem cells have an interesting history that has been somewhat tainted with debate and controversy (Murnaghan). Animal cells were originally discovered in the mid 1800’s, but stem cells specifically were discovered much later in 1978. These cells were found in human cord blood, the blood that remains in the placenta and umbilical cord after childbirth. Then in 1998, a researcher from the University of Wisconsin isolated the first human embryonic stem cells from the inner cell mass of a young embryo. Since this was the sole original source of human stem cells for scientists, it created an initial counter argument for the continuation of stem cell research.
Critics argued the morality of obtaining the stem cells, reasoning that it increased the demand for abortions, an already highly controversial procedure. Much of these initial objections stemmed from conflicting religious beliefs. In 2007 however, researchers discovered that human stem cells could be harvested from amniotic fluid, the fluid which bathes the fetus in the womb. This allowed scientists to obtain the human stem cells for research and application without having to compromise any fertilized eggs, collections of cells that would have otherwise become human beings.
It has since been discovered that stem cells are present in many tissues throughout the human body. Adult stem cells have been found in the brain, bone marrow, blood vessels, skeletal muscle, skin, teeth, heart, gut, liver, and other organs and tissues (Boston Children’s Hospital). Usable adult stem cells can be derived from all of these sources through a variety of processes such as chemical treating and transdifferentiation. Then in 2016, scientists from Harvard Medical School acquired 73 hearts deemed unfit for transplant. Through a process of manipulation of RNA, they were able to turn skin cells into pluripotent stem cells. They then used these stem cells to replace damaged cells on the donor organs. After providing them nutrients for nearly two weeks, the hearts began to repair themselves. Eventually, they were able to beat again when given electricity. The hearts in this experiment were not able to be transplanted due to maturity complications, but this is the closest scientists have come to creating the first transplantable lab grown organ and it shows the potential this technology holds.
In modern medicine, there is a major problem regarding organ donor waiting lists. Every ten minutes, someone is added to the national transplant waiting list, and on average, 20 people die each day while waiting for a transplant (UNOS). In those that do receive the transplant they need, there is still the very real risk of bodily rejection of the organ. In all transplants, there is some degree of acute, or short term, rejection. There is also possibility of chronic rejection over a period of time, usually a few years. These complications can cause a long list of very harmful side effects, all due to the fact that the body recognizes the organ as a foreign entity. Since the body recognizes the tissue in the organ transplanted as not its own, it uses the body’s immune system to attack said tissues. Combatting this leads to patients taking immunosuppressant drugs, which have horrible side effects of their own.
All of these negative aspects of organ transplantation could be completely solved through stem cell research and application. If we were able to create organs on demand, specified to a case by case basis, it would completely eliminate the need for organ donation programs. The organs that would otherwise be used for transplants could then be utilized for a different purpose, possibly for students to study legitimate cadavers more readily. Stem cells also have the potential to revolutionize the recovery process for transplant recipients. In theory, because the patient’s own stem cells are used to lab create the organ they need, when it is transplanted there is little to no chance of rejection. This is because the body will recognize the tissue as originating from its own body, not a foreign source.
Due to there being such a great potential for improvement of life, we have an extreme moral obligation to support and continue stem cell research. Victims of horrible accidents will soon be able to repair their bodies virtually perfectly, and therefor go on to live lives as if no accident had even happened. Patients in need of transplants will no longer have to sit aside, waiting for and organ that may never come with the possibility of dying in the meantime. Far down the line, there is even the possibility of immortality. If we were able to replace any part of someone’s body, be it an organ, bone, or limb, when it becomes faulty, you could in theory keep that person alive forever! At the very least, this field of research could drastically increase our life expectancy. With the majority of people being able to live longer, healthier, happier lives, it will lead to the betterment of society as a whole.
The excitement about stem cell research is primarily due to the medical benefits in areas of regenerative medicine and therapeutic cloning (Phillips). Although research in stem cell technology has made incredible advancements in the past decade, it is still a very young scientific field with much more to discover. The critical issue with organ engineering outside of the body is the limited availability of human cells, a suitable matrix with the same composition and architecture of the target issue, and the ability to maintain the viability of the organ without a blood supply (Belair). Regarding the availability of human cells, stem cells come from a variety of sources. The original and somewhat impractical source is from embryos. These are called embryonic stem cells, and their use comes with advantages as well as disadvantages. The upside is they can be specialized into any cell type in the human body, but given their limited supply, as well as being acquired in a morally contradictory way makes them somewhat unfavorable. Alternatively, pluripotent stem cells, derived from the patient’s own adult cell tissues, provide a much more practical source of usable stem cells. Pluripotent stem cells provide a potentially unlimited source of human cells, due to their unlimited growth potential, with which to derive most of the cell types of the body (Belair). So far, the only downside is scientist have not yet discovered reliable methods to fully specialize these cells into the specific desired organ cell types.
The next big challenge scientists face is maintaining the organ’s health while it is being developed. Since the main organs of interest; heart, liver and kidney, have limited vascularity, it presents an additional challenge of keeping the tissue alive. Very often, the stem cells die of hypoxia in development, a lack of oxygen stemming from the organ’s limited vascular system. To combat this, researches have been experimenting in creating oxygen rich, nutrient dense environments to contain the organ during its creation. Through processes of chemical treating, many potentially useful methods have emerged.
A process that has shown to be one of the most promising for creating new organs involves essentially growing them inside of another animal. In particular, biologists from the Salk Institute succeeded in growing human stem cells in pig embryos. The approach involves generating stem cells from a patient’s skin, growing the desired new organ in a large animal like a pig, and then harvesting it for transplant into the patient’s body (Wade). This type of animal, one with both human and another species cells making up its body, is called a chimera. Creating the chimeric embryos takes two stages. First, a technique known as CRISPR gene editing is used to remove DNA from a newly fertilized pig embryo that would enable the resulting fetus to grow the desired organ (Walsh). Then, human induced pluripotent stem cells are injected into the embryo (Walsh). The altered embryo is then inserted into an adult pig to be developed naturally, and it is hoped the resulting fetus will contain the organ desired. Juan Izpisua, professor at Salk Institute, said the new research is “just a very early step toward the goal” (Tribune).
Advantages to this process include that the pig acts as a controlled environment, solving the issue of keeping the organ alive and safe during its creation. Walter Low, professor in the department of neurosurgery, University of Minnesota, said pigs were an ideal “biological incubator” for growing human organs (Walsh). Also there is the fact that it uses induced pluripotent stem cells, those that have an unlimited growth potential and therefor unlimited supply. This process is also somewhat controversial, stemming from the fear of a pig developing some human like traits. The main concern is that the human cells might migrate to the developing pig’s brain and make it, in some way, more human (Walsh). Although this is a possibility, it is very unlikely under professional supervision, and the potential benefits to society far outweigh the life of a single pig. Also, just as with much of stem cell application currently, much of these ideas are still evidence supported theory and have yet to be perfected in a laboratory setting.
A main benefit and driving point to organ creation via stem cells is that it virtually eliminates the possibility of bodily rejection of the transplant. In all of these cases, since the organ would be made of a patient’s own cells, there would be little risk of immune rejection (Wade). At the cellular level, biological entities are covered in formations called antigens. These antigens are unique to every object, disease, virus, etc. As well as foreign objects, the cells and tissues of your own body are covered in unique antigens. Through this mechanism, your body is able to recognize a cadaver organ transplant as not originating from the host, and attacks it as it would a bacteria or virus. Alternatively, when you create an organ from stem cells originating from the patient’s own body, the resulting organ is covered in the same unique antigens as the rest of the host. Therefor, after an organ transplant the body would accept the new organ as its own and would not use the immune system to attack it.
It is my belief that within our lifetime we will see this technology advance significantly. Beyond our lifetime, this technology will indefinitely advance to the point of theoretic immortality. One day humans will have a world in which no one lives with severe bodily trauma or complications. If a part of someone’s body begins to fail, they will simply grow themselves a new one. Given this, these future generations of humans will grow much smarter and wiser over time. A population in which everyone lives well beyond two hundred years is a population full of extremely wise, life tested people.
Our society should invest significant amounts of time and resources in pursuit of advancing this technology further, because it is our responsibility as educated, intelligent humans to better the lives of generations to come. We have the opportunity to create a world far better than our own, all the while discovering ridiculously interesting secrets of our biology. Given that the number of lives this technology could save over the span of time is virtually infinite, it only makes sense support and appreciate.
In conclusion, the use of stem cells to grow artificial organs for transplant has the potential to revolutionize the medical industry. Organ donation programs will no longer be needed, as organs will soon be able to be grow specifically for each recipient. These transplantations will come with virtually no risk of bodily rejection, because the cells are derived from the patient’s own body. In current day, this technology is on the verge of breakout. Scientists are still in early stages, but with more research and effort all of this speculation may become reality. As time goes on, theres no telling where this technology may lead. We have the opportunity to finally take control of and manipulate our species biology, carving the path of our future in our own direction.
- Ossola, Alexandra. “Scientists Grow Full-Sized, Beating Human Hearts From Stem Cells.” Popular Science, 16 Mar. 2016, www.popsci.com/scientists-grow-transplantable-hearts-with-stem-cells.
- Belair, David. “Stem Cells Will Eventually Revolutionize Organ Transplants, And This Is How.” Forbes, Forbes Magazine, 2 June 2016, www.forbes.com/sites/quora/2016/06/02/stem-cells-will-eventually-revolutionize-organ-transplants-and-this-is-how/#5138004146f9.
- Murnaghan, Ian. “History of Stem Cell Research.” History of Stem Cell Research, 23 Apr. 2017, www.explorestemcells.co.uk/historystemcellresearch.html.
- Boston Children’s Hospital. “Where Do We Get Adult Stem Cells?” Boston Children’s Hospital, 1 Dec. 2017, stemcell.childrenshospital.org/about-stem-cells/adult-somatic-stem-cells-101/where-do-we-get-adult-stem-cells/.
- UNOS. “Data.” UNOS, 7 Dec. 2017, unos.org/data/.
- Wade, Nicholas. “New Prospects for Growing Human Replacement Organs in Animals.” The New York Times, The New York Times, 26 Jan. 2017, www.nytimes.com/2017/01/26/science/chimera-stemcells-organs.html.
- Walsh, Fergus. “US Bid to Grow Human Organs for Transplant inside Pigs.” BBC News, BBC, 6 June 2016, www.bbc.com/news/health-36437428.
- Phillips, Theresa. “Stem Cell Research: Weighing Both Sides of the Debate.” The Balance, 11 Oct. 2017, www.thebalance.com/pros-and-cons-of-stem-cell-research-375483.
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