Understanding Human Stem Cells
The human body is able to function through an incredible system of teamwork between different organ systems, organs, tissues, cells, and their organelles, along with other materials such as water, oxygen, carbon and many other chemical ingredients. Over 30 trillion cells are responsible for creating, and sustaining human life. Stem cells are extremely valuable because in early stages of development they are able to specialize into different cell types in order to meet various needs within the body. Stem cells replace themselves with great efficiency through the process of cell division and in this way they are able to act as a repair system, by either replacing damaged stem cells or by differentiating into a more specialized cell such as a muscle cell or a red blood cell. Disease or injury within the body have the ability to be repaired because mature stem cells are capable of replacing damaged tissues or organs with new healthy cells. An incredible example of stem cell treatment would be the use of bone-forming stem cells for bone marrow transplantation which can help save people suffering from blood cancers such as leukemia.
In vitro fertilized embryos produced and donated for implantation are not all used, and are therefore discarded by couples who no longer require them. These embryos - less than a week old - are the source used in creating human embryonic stem cells. Pluripotent stem cells are undifferentiated and became crucial in research because of their ability to proliferate indefinitely in culture to form almost any type of specialized adult cell. An interesting ethical debate regarding the advancements with cell research rises from the practice of in vitro fertilization. Scientists have the ability to test embryos for genetic diseases and defects before they are even implanted. This often leads couples to choose not to use the embryos containing defects, a scary thought when considering the ability that science is giving humans to choose and control life. Despite possible concerns, parents who donate these defective embryos are also giving researchers the ability to study the diseases and defects with hopes of furthering treatments and maybe even cures.
The ability to grow specific cell types outside of the human body creates the opportunity to test chemicals on cells specific to certain diseases and observe any responses that the cells have to these treatments. A benefit of this kind of research is that cultured human embryonic stem cells are not considered to be living beings. If transferred into a woman’s uterus, they would not successfully develop into a fetus. This is because the embryonic stem cells are derived from the inner cell mass of an embryo and are therefore not the same as the intact embryo. The ethical issue here is that the embryonic stem cells are derived from embryos that could have otherwise grown to become human beings. However, many embryos that are not used for in vitro fertilization are bound to be discarded and incapable of becoming human beings regardless. When donating these unused embryos, the possibility for life is taken away from that specific embryo, but that donation may lead to the direct saving of another human beings life, and at the very least it will further research and studies required for more life-saving treatments.
Still, science advanced even further so that human blastocysts (hES) are now no longer the only way of obtaining pluripotent stem cells. Induced pluripotent stem cells (iPS) can be taken from a living and functioning human body and genetically reprogrammed to act in a very similar way to that of a pluripotent embryonic stem cell. This discovery meant that embryos no longer needed to be destroyed for their ability to create undifferentiated cells. Induced pluripotent stem cells can be stimulated to differentiate into almost any type of cell, which could be used to treat many different diseases. Cell fusion, which involves adult somatic cells being grown in culture with embryonic stem cells and fusing with the stem cells in order to take on embryonic stem-cell-like properties, led to the belief that specific genes could reprogram differentiated adult cells. This does not rely on eggs, it requires only the use of existing embryonic stem cells. The issue with this discovery is that the human body commonly rejects fused cells. In order to make adult cells pluripotent without fusing them to embryonic stem cells, genes that can induce pluripotency need to be transferred into the nuclei of adult cells which can only be done with specific combinations of genes inserted into retroviruses (convert RNA into DNA). It is the retroviruses which deliver RNA of regulatory genes into the nuclei of the adult cell, where the genes are then meant to develop with into the DNA of the cells. In this way, induced pluripotent stem cells are different than embryonic stem cells, while serving a very similar function in research and disease-specific treatment. Though iPS may appear to raise less concerns ethically, both hES and iPS are still considered crucial in furthering cell research.
Somatic cell nuclear transfer (SCNT) is working to successfully transfer the nucleus of a fully differentiated human, somatic cell into an unfertilized egg cell that had its own DNA removed, creating the ability to grow a new embryonic stem cell line. This does not come without its ethical controversy either, as the possibility for cloning humans becomes the new area of concern. The new generations of cells being grown in culture all originate from the same parent cells, and are therefore identical to the original cells. The benefit of this would come from the ability to treat the diseased donor with no fear of the body rejecting the new cells. However, SCNT can require more than a dozen eggs in order to create one successful embryonic stem cell, and ethical issues continue to arise surrounding the donation of eggs, especially considering that human eggs are not produced very abundantly. This study is a long way from being legal and safe for real treatment, and carries the possibility for real human cloning, therefore leaving many people in opposition to its furtherance.
While the world of science continues to develop and advance in many incredible ways, there will always be a need to balance the power we have as humans to create and discover, with the need we have as humans to maintain values, and respect beliefs. There are many who believe that while we have evolved (or have been given the ability) to use our minds and our earth to create and discover amazing things, there remains a need to honour the beauty of human life as it is naturally developed. People who support this may be uncomfortable with the idea of choosing not to have a baby because it may have a defect or disease, while others may believe that those who live with diseases are given a life of pain or sadness and that humans should have the right to avoid allowing those lives to begin. Some may believe that people should not be cloned, or that humans should not have the power to choose how our babies will appear physically. No matter what the value, there will always be a need to balance rights. Do people who are already alive have more of a right to be healed or given more time to live than people who are not yet born? Do the benefits of studying stem cells for treatment outweigh the ethical issues regarding the destruction of eggs and embryos? As humans we are required to determine and implement boundaries for ourselves, while also fighting the urge to want to heal and to discover, and to cure. Stem cell research continues to be one of the most controversial areas of study with many new areas of ethical consideration. Stem research also continues to be crucial for the discovery of life-changing and life-saving treatments and medical advancements.
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