Stem Cell Research
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Stem cells have been defined as cells that have retained their ability to divide and differentiate into different types of body cells. Unlike ordinary cells which stop replicating upon maturity, stem cells keep dividing and can be transplanted to repair body tissue or missing cells.
Stem cells are generally classified into 3 different kinds:
- Embryonic stem cells (ESCs) – Obtained from early mammalian embryos that are in the blastocyst stage of growth. These cells are obtained from embryos that are either created in-vitro with the approval of the donors or from aborted fetuses and have often been a major point of criticism against stem cell research. However, they are the most proliferative kinds of stem cells and are capable of unlimited division and differentiation.
- Adult or somatic stem cells (SSCs) – Some cells present in tissues like the bone marrow, blood and brain and have the ability to divide. Their ability to differentiate, however, is limited. For example, hematopoietic stem cells derived from the bone marrow can only differentiate into blood cells.
- Induced pluripotent stem cells (iPSCs) – These are also known as “true stem cells” as they are obtained from somatic cells and can be artificially induced to differentiate into almost any kind of cell.
Stem cells have been successfully used to cure or reduce the impact of several diseases. Type-1 diabetes, for instance, is a disease where the body shows an auto-immune reaction against the insulin producing cells of the Islets of Langerhans and destroys them, leading to a deficiency of insulin and a resulting inability to control blood sugar level and several vascular complications. While it is possible to transplant parts of the pancreas containing islets from a donor, such transplants are often complicated and are often rejected by the body. Stem cell research has made it possible to induce the splenic stem cells to divide, differentiate and mature into functional islet cells that secrete insulin, to restore normal glycemic levels. Similarly in Parkinson’s disease, Alzheimer’s disease, amyotrophic lateral sclerosis and multiple sclerosis, cells that secrete an important neurotransmitter or nerve cells or their coating themselves die. Such diseases can be cured only if these cells can be regenerated or recreated artificially from pluripotent stem cells. Hematopoietic stem cells transplantation in patients suffering from immunodeficiency’s like myeloma, chronic lymphatic leukemia, severe combined immunodeficiency, etc. has already shown considerable success if done at an early stage of the disease. Mesenchymal stem cells from the bone marrow can also be used to regenerate or replace bone, tendon, skeletal muscle and cartilage in patients who have diseases like osteogenesis imperfecta or chondrodysplasias or who have had a limb amputated. Such diseased were earlier untreatable and often extremely painful and debilitating (Kumar, Kumar, & Nishanth, 2011).
Despite its ability to save lives that would otherwise have been lost and improve the quality of life for many others who were earlier suffering, stem cell therapy has always been controversial. Embryonic stem cells, which are totipotent and have the potential to develop into almost any kind of cell, are obtained from early human fetuses in the blastocyst stage. Stem cells now have also been derived from many other somatic sources that do not require fetuses to be harmed (Ramachandran & Yelledahalli, 2011).
Some researchers claim that since fertilized embryos are destroyed in order to procure embryonic stem cells, this kind of research is unethical and immoral. It is however, essential to note that these embryos are either created in-vitro from donated cells for the sole purpose of research and are not meant to be used for reproduction or taken from aborted fetal tissue after informed consent of the donor. It is currently against the law for “parents” to give their natural or IVF embryo for stem cell research.
Courts in Tennessee have already ruled that the correct term for the organism from to fertilization to 14 days was “pre-embryo” as it cannot be regarded as a person. It must also be noted that only 1 American state, Louisiana considers embryos to be people from their conception and grants them rights. The remaining states claim that the pre-embryo is “not entitled to the protection of a person”. In fact, the American law permits abortion until the end of the first trimester. Does that imply that killing a developing embryo purposelessly is permitted but destroying a pre-embryo that hasn’t even been implanted for the purpose of saving lives is a heinous crime?
For the purpose of in vitro fertilization several eggs are fertilized and only 2 or 3 of those embryos are implanted into the mother’s womb. Since the remaining embryos are wasted, it would be more “ethical” to use these extra embryos to save lives rather than drain them down the sink. However, the law that permits women to decide whether or not they wish to continue with their pregnancy does now allow them to decide the fate of the extra embryos that they have paid for and had artificially developed by means of IVF. Even if an IVF pre-embryo were to be kept preserved in its frozen state with the intent of donation or future use, it would only remain viable for 2 years, after which it would no longer be usable. Such unused embryos can easily be used to create embryonic stem cell lines that can be used to give an extended life to someone. So instead of viewing this as killing an embryo, it should be considered as granting life to a human being.
Also since it is not possible for human embryos to develop beyond the blastocyst level in vitro, it is irrational to consider the embryo to be alive at this stage. In fact, even in the human body almost 1/5th of the time the fertilized eggs do not implant in the uterus and are therefore, lost. By this argument, a fertilized egg, before it implants into a female uterus, is lifeless. The blastocyst is merely a mass of cells and has no human characteristic. It is also a known fact that the primitive streak (which later become the neural tube, or in humans, the spinal cord) is formed around 14 days after fertilization and until that time, a fertilized embryo can split into two to form monozygous twins, or two separately fertilized eggs can fuse to form a tetragametic cell. Until then, human life cannot be ascertained.
Advancement in stem cell research has resulted in stem cells being extracted from cord blood and other somatic cells as well. However, these grow slower than embryonic stem cells, are harder to isolate and have limited potential to differentiate. There are still many tissues for which stem cells have not been isolated and the only alternative is to opt for embryonic stem cell therapy. As is in the case with cord blood, most adult stem cells are available in very small quantities, divide slower and cannot be used for treatment directly but need to be cultured to divide, which is a long and costly process. It is clear after research that embryonic stem cells are superior in quality to adult stem cells and provide better, more permanent cell lines. Adult stem cell therapy is not the best choice for treatment of genetic diseases as stem cells are normally taken from a family member to avoid strong immune reaction and therefore, carry the same genetic abnormality. Somatic stem cells are also more mature and have often been exposed to mutagens and thus, may have deformed DNA. However, wherever possible, research is trying to utilize adult stem cells and reduce the dependence of technology of embryonic cells (Islets of hope, 2008).
It has also been widely criticized that stem cell research is privatized and therefore it is a gimmick to make money. On the other hand, it is imperative to have private research centers in the country to create more competition and lead to better, cheaper and quicker results or for verification of the results achieved. Moreover, the government has, until now, refused to fund labs where stem cell research is conducted, leaving privatized research as the only resort. We should understand that privately funded research may very well be done with the intention of making money, but as long as it benefits society as a whole, we cannot look down upon it.
In such arguments, the cost of an embryonic life is weighed against the lives of several actual living and breathing people as an embryonic stem cell line can be used almost indefinitely if required. If research is allowed and promoted, researchers will find a way to cure several diseases that regularly claim innocent lives. There is no doubt that the benefits of stem cell research – the social, economic and emotional benefits, by far outweigh the cost of destroying a few artificial embryos. To condemn stem cell therapy in order to save an unborn embryo is to condemn millions of people suffering from potentially curable disease to long painful deaths. Without an open mind and positive outlook towards research such breakthroughs will not be possible.