Imagine you have been diagnosed with a disease, and you are told that there is no cure. There are treatments available to help with your symptoms, but they do not guarantee your quality of life, nor how much time you have left. Your doctor tells you that there are experimental treatments available, research studies you can participate in. The study mentioned in particular involves the use of embryonic stem cells.
Medicine is no stranger to the use of stem cells. A stem cell is defined as “a cell that has the ability to continuously divide and differentiate (develop) into various other kinds of cells [or] tissues” (Barker et al., 2013). In 1956, Dr. E. Donnall Thomas performed the first bone marrow transplant in Cooperstown New York. Bone marrow is a spongy tissue found in the center of bones, and it contains cells called haematopoietic (or blood-making) stem cells. Bone marrow is usually extracted from the lower spine using a needle. To obtain embryonic stem cells, however, scientists must harvest an embryo.
Scientists learned how to harvest stem cells from embryos in 1998, and while it was a major breakthrough, controversy also sparked as a result of it. Embryonic cells have a huge potential to help cure diseases and form treatments, but they could not be obtained without “destroying human embryos”. In 2006, scientists learned how to manipulate human cells to behave like stem cells. This breakthrough could have ended the controversy, but embryonic stem cells were still needed. The manipulated cells, called pluripotent cells, are compared to embryonic stem cells to determine how well they will work. Embryonic stem cells are also used as a control group in experiments. However, the other ethical issue present is that the manipulated cells have the potential to turn into clones of the donor. Most countries have passed laws to prevent this from happening, but it remains an ethical issue.
We now know what makes embryonic stem cell therapy so controversial, but does the end justify the mean? Is it ethical to use embryonic stem cell therapy to help treat diseases that have no known cure? What if embryonic stem cells can be used to cure diseases that were otherwise incurable? In the case of neurodegenerative disorders, there are no known cures. Doctors treat symptoms to help improve the quality of life of those who have neurodegenerative disorders. But, could stem cell therapy help reverse the damage done by the disorders?
Stem cells have been used for the purpose of replacing and restoring cells lost through neurodegeneration in patients with Parkinson’s Disease, Multiple Sclerosis, Huntington’s Disease, Motor Neuron Disease, and others (Pen et al., 2016). Trials were designed to replace dopamine cells in patients suffering from Parkinson’s Disease; many younger participants benefited, but were not protected from disease progression (Pen et al., 2016). The common thread among various neurodegenerative disorders is the atypical protein formation and the induction of cell death (Barker et al., 2013). Stem cells, whether they are pluripotent cells that have been synthesized in a lab or embryonic stem cells, can be grown and differentiated into a relevant cell type to replace cells lost in a disease process (Barker et al., 2013). Clinical trials are not abundant because pluripotent cells, which is seemingly the more ethical of the two, are still being refined (Barker et al., 2013). In addition to this, trials have not been conducted on humans because choosing who gets to participate poses another ethical dilemma (Barker et al., 2013). Factors such as age, disease type, duration of the disease, prognosis must all be considered when determining the subject pool for a study. Neurodegenerative disorders are not identical from person to person, thereby making the recruitment process of finding individuals whose diseases and situations resemble each others quite difficult.
Stem cell transplantation has been used in closely related fields, such as spinal cord injuries. For example, patients with complete spinal cord injuries were able to improve their neurological functions with the use of stem cells without severe adverse effects, and the damage done to the white matter tracts in the spinal cords were repaired (Barker et al., 2013). This lead to improvement in transmission of signals to and activity of the muscles in their legs. This change shows that the use of stem cells holds a new potential for treatments in the spectrum of neurological diseases (Barker et al., 2013). Scientists believe the same techniques can also be applied to diseases such as Alzheimer’s Disease and Parkinson’s Disease, hopefully, reversing the damage done by the neurodegeneration. Stem cell use in the treatment of any disease will cause ethical questions to arise, it is no different when talking about its use in the treatment of neurodegenerative disorders. Stem cells have the potential to improve quality of life, decrease the progression of disease, and maybe even cure these disorders. However, we must ask ourselves, is it benefitting the greater good?
Australian Cancer Research Foundation. (2017, January 17). The first bone marrow transplantation in 1956 changed cancer treatment. Retrieved November 28, 2018, from https://home.cancerresearch/1956-the-first-successful-bone-marrow-transplantation/
Barker, R. A., & Beaufort, I. D. (2013). Scientific and ethical issues related to stem cell research and interventions in neurodegenerative disorders of the brain. Progress in Neurobiology,110. doi:10.1016/j.pneurobio.2013.04.003
Genetic Science Learning Center. (2014, July 10). The Stem Cell Debate: Is it Over? Retrieved November 28, 2018, from https://learn.genetics.utah.edu/content/stemcells/scissues/
Pen, A. E., & Jensen, U. B. (2016). Current status of treating neurodegenerative disease with induced pluripotent stem cells. Acta Neurologica Scandinavica,135(1). doi:10.1111/ane.12545
dear Amna. You have touched on the future of medicine. The ramifications are multiple, possibilities are vast, ethical questions are many. I have loved your a beautiful article. Thank you.