Stem cells are special human cells that have retained their ability to differentiate. They can specialise to become anything from a muscle cell to a brain cell. Stem cells can be used to replace damaged or diseased cells with healthy, functioning ones.
There are 3 types of stem cells: Embryonic stem cells, Cord Blood stem cells and adult stem cells. Embryos can be deliberately created by fertilizing egg cells with sperm and allowing the resulting zygote to develop for a few days until it has between four and sixteen cells. All of the cells are embryonic stem cells. Blood can be extracted from the umbilical cord of a new-born baby and stem cells obtained from it. The cells can be frozen and stored for possible use later in the baby's life. These are referred to as Cord Blood cells. Stem cells can also be extracted from an adult’s tissues – these are adult stem cells. These types of stem cells vary in their properties and therefore in their potential for therapeutic use.
Embryonic stem cells have almost unlimited growth potential and can differentiate into any type in the body. However, they have a greater risk of becoming tumour cells than with adult stem cells but have less chance of genetic damage due to the accumulation of mutations than with adult stem cells. They are also likely to be genetically different from an adult patient receiving the tissue. Taking cells from an embryo kills it, unless only one or two cells are taken. This may also cause serious developmental issues when the embryo develops. Hence there are many debates as to whether the use of embryonic stem cells is ethical or not.
Cord Blood stem cells can be easily obtained and stored. Commercial collection and storage services are already available and it is relatively common to keep these cells. They are fully compatible with the tissues of the adult that grows from the baby, so no rejection would occur. They do only have a limited capacity to differentiate into different cell types and naturally develop into blood cells. They are limited in number. The umbilical cord is discarded whether or not stem cells are taken from it and has no impact on the development or growth of the individual.
Adult stem cells are difficult and painful to obtain as there are very few of them and they are buried deep in tissues. They have lesser growth potential than embryonic stem cells and a Lesser chance of malignant tumours developing. Their capacity to differentiate is also limited. Although, they are fully compatible with the adult's tissues, so rejection problems do not occur. Removal of stem cells does not kill the adult from which the cells are taken.
Embryonic cells are incredibly valuable because they provide a renewable resource for studying normal development and disease, and for testing drugs and other therapies. Human embryonic stem cell (HESC) research offers much hope for alleviating the human suffering brought on by the ravages of disease and injury. Despite the tremendous therapeutic promise the research has met with heated opposition because the harvesting of HESCs involves the destruction of the human embryo. The moral debate as to when a human being truly begins to exist is unclear and highly controversial, due to which it has caused heated debate over the use of these cells. Some argue that killing a human embryo is equivalent to killing a human whilst others argue that the embryo is not a human being until it has a heartbeat and these are many other points of view. The unclarity and ethical dilemma over embryonic stem cells have led to many horrifying cases and illegal activities.
Saviour Siblings
A saviour sibling is a child that is born to donate stem cells or an organ to a sibling with a fatal condition. There is a large ethical debate as to whether saviour siblings should exist. Some argue that It is unethical to bring a child into the world for the sole purpose of keeping another alive, whilst others say it is better to save a life than actively let it die. There have been quite a few reported cases of saviour siblings but the exact number is still unknown.
The story of Henrietta Lacks
Henrietta Lacks was a black woman whose cancer cells are the source of the HeLa cell line, the first immortalized human cell line and one of the most important cell lines in medical research even in the present day. Lacks was the unwitting source of these cells from a tumour biopsied during treatment for cervical cancer at Johns Hopkins Hospital in Baltimore, Maryland, the U.S. After giving birth to her 5th child she was diagnosed with cancer. Tissue samples from her tumours were taken without consent during treatment and these samples were then subsequently cultured into the HeLa cell line. Cells from this immortalized cell line, that can still be easily obtained today, were obtained in 1970. However, the Lacks family was not made aware of this until 1975. No consent was obtained to culture her cells, nor were she or her family compensated for their extraction or use. With knowledge of the cell line's genetic provenance becoming public, its use for medical research and for commercial purposes continues to raise concerns about privacy and patients' rights.
Bibliography
Butanis, Benjamin. “The Legacy of Henrietta Lacks.” Hopkinsmedicine.Org, 12 Apr. 2017, www.hopkinsmedicine.org/henriettalacks/.
Lo, Bernard, and Lindsay Parham. “Ethical Issues in Stem Cell Research.” Endocrine Reviews, vol. 30, no. 3, May 2009, pp. 204–13, doi:10.1210/er.2008-0031.
Rivard, Laura. “Case Study in Savior Siblings | Learn Science at Scitable.” Www.Nature.Com, 11 June 2013, www.nature.com/scitable/forums/genetics-generation/case-study-in-savior-siblings-104229158/#:~:text=Children%20born%20in%20this%20way.
Siegel, Andrew. “Ethics of Stem Cell Research (Stanford Encyclopedia of Philosophy).” Stanford.Edu, 2018, plato.stanford.edu/entries/stem-cells/.
Allott, Andrew, and David Mindorff. Biology : Oxford IB Diploma Programme. Course Companion. Oxford University Press, 2014, p. 15.
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