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Oriel Zagazeta is a biology major with a chemistry minor and is a 2022-23 health care ethics intern at the Markkula Center for Applied Ethics. Views are his own.
The use of stem cells in health care has revolutionized the way diseases and illnesses can be addressed and treated. Stem cell research has furthered scientific discovery to understand disease progression and drug function. This article will explain what stem cells are, how stem cells can be used in research and health care contexts, and address ethical issues surrounding stem cell use.
Understanding Stem Cells
Stem cells are special cells that have the ability to differentiate into any other cell type. Stem cells can be used as a treatment for certain diseases and are commonly found in three types: Embryonic stem cells, Donor-Sourced (Adult) stem cells, and Induced Pluripotent Stem Cells (iPSCs).
Embryonic Stem Cells
Embryonic stem cells are typically sourced from in vitro fertilization clinics. To prepare for IVF,5.07-9.74 embryos (blastocysts) are created on average per cycle and stored for the prospective parents. Often, only two to three of these stored embryos successfully result in a pregnancy, while the remaining embryos are stored indefinitely. In California, parents are then given options by the health care provider for the IVF clinic to continue to store the embryos, discard the embryos, donate the embryos to another individual, or donate them for stem cell research (mainly to improve IVF techniques). Outside of IVF clinics, some regulations are in place to limit embryonic formation solely for research purposes, such as the 14-day rule which only allows embryonic research for 14 days post-fertilization.
Although embryonic stem cells have been a source for stem cell research for years, some question the ethics of taking away potential human lives for research and treatment possibilities. In contrast to in utero embryos, do these embryos have more or fewer rights? Due to ethical dilemmas surrounding IVF and embryonic stem cell sourcing, current research and treatment have moved towards other stem cell sources.
Donor-Sourced Stem Cells
Donor-sourced stem cells (adult stem cells) come from a living donor from sources such as bone marrow or umbilical cords. Like embryonic stem cells, donor-sourced stem cells must be histocompatible to the recipient, limiting the amount of viable donors per patient. Retrieval of donor-sourced stem cells (especially from bone marrow) can also be invasive, requiring the use of a general anesthetic. Not only can this cause complications in producing high volumes of stem cells for treatment purposes, but donor-sourced stem cells require informed consent, testing, and donor-recipient tissue type matching, which can act as roadblocks to treatment.
Despite this, the use of blood-forming stem cells (hematopoietic progenitor cells) is currently the only FDA-approved stem cell therapy to treat certain cancers and diseases that may affect the blood and immune system. These can be sourced from umbilical cord blood or less commonly bone marrow transplantation. Only umbilical cord-sourced blood is regulated by the FDA.
Induced Pluripotent Stem Cells
Induced Pluripotent Stem Cells (iPSCs) are a specific type of stem cell produced by taking any human somatic cell and reverting it to a human stem cell through the influence of viral-delivered or transposon-inserted transcription factors. The Takahashi group were the first to create iPSCs in mice and later in humans, causing a revolution in stem cell research and prospective clinical application.
What makes iPSCs different from embryonic or donor-sourced stem cells? Primarily, iPSCs sidestep ethical issues of the fetus’ right to life and the donor’s informed consent since iPSCs can be sourced from the patient directly. iPSCs are also minimally invasive, with capabilities to be formed from patients’ skin, blood, or even urine samples. Moreover, by using the patient’s own cells to form iPSCs, the stem cells used for their treatment will be autologous. This means they will share the same genetic information, cell markers, and have ideal histocompatibility. This ensures lower chances of treatment rejection and allows for continuous production of individualized treatment as necessary. Due to these benefits and other advancements in iPSC formation, iPSCs have taken the stem cell research industry by storm.
Conversely, studies have linked iPSCs with cancer-causing mutations, which can be easily obtained due to the amount of replication necessary for therapeutic quantities in vitro. Since stem cells live longer than typical cells, they can be more susceptible to acquiring these cancer mutations and their ability to differentiate could lead to dangerous metastases within the human body. Thus, we must balance the ethical principles of beneficence and nonmaleficence. Is it worth it to use stem cells as a form of medicine when we may introduce something which has the potential to cause even more harm to the patient? Until we can resolve this issue, cellular therapies will likely remain experimental.
Stem Cell Research and Medicinal Opportunities
Eventually however, practical issues surrounding stem cells will be resolved. As a glimpse towards the future, it is not a question of if stem cells will take hold in healthcare, but when. Current iPSC research aims to establish iPSCs as a viable treatment in regenerative medicine as cures for retinal degeneration, myocardial infarction recovery, skeletal muscle recovery, and more such as neurological/spinal diseases and diabetes. Some may even see a future where stem cells become available as direct-to-consumer products for professional athletes to repair injuries or to assist with bone fractures.
In the field of research, scientists have been able to effectively grow chimeral rat pancreases in mice, which could lead to the generation of human organs in farm animals for organ transplants. Moreover, other studies are able to more easily examine human organoids to better understand pancreatic cells and neural circuits ex vivo during the stages of human development. This could lead to novel findings about insulin and neurological diseases.
In light of these advancements we must keep in mind issues of justice, as individuals of higher socioeconomic status may be more likely to afford these life-altering treatments. This has been shown in the rise of stem cell tourism, or travel to countries with accepted stem cell therapies in hope of curing these chronic diseases. Patients spend tens of thousands of dollars to travel and seek treatment, often to no avail. Those of lower socioeconomic status do not have these opportunities and when cellular therapies become common in healthcare, regulations must be formed to promote equality for all patients.
Conclusion
Stem cell research and healthcare hold great promise for treating a range of diseases and injuries. The advancements in stem cell technology have allowed for great progress in the field of regenerative medicine, however ethical questions relating to beneficence, non-maleficence, autonomy, informed consent, and justice must be upheld in stem cell research and healthcare. As the field continues to evolve, it is important to remain vigilant and thoughtful in our approach to stem cell research and health care, ensuring that we balance innovation with responsibility and ethical considerations.
Call to Action
As individuals, we can support ethical stem cell research by staying informed and advocating for policies that promote the responsible use of stem cells. We can also consider becoming stem cell donors, providing a potentially life-saving resource for those in need. Let us work together to ensure that the tremendous potential of stem cell research is realized in a way that is ethical, equitable, and beneficial for all.