Stem Cell Research on Curing Genetic Disorders
Genetic disorders cannot be cured with existing treatments. The progression of genetic disorders can be slowed and the symptoms can be managed, but people with genetic disorders have to live with getting treatments throughout their entire lives. Fortunately, there may be a way to cure genetic disorders, but it may take decades before becoming a clinical treatment. Stem cells, which are the cells that can differentiate into any type of cell, can be manipulated to make healthy cells to take the place of mutated cells. Stem cell treatments can be done on embryos and on people already born.
One area of genetic disorders is mitochondrial disorders. There are over 200 known mutations in the genes of mitochondria, the powerhouse of the cell, that cause mitochondrial disorders (Wallace 2013). Each mutation produces a different disorder such as vision problems, diabetes, and seizures (Sadun 2006). Juan Carlos Izpisua Belmonte, a professor in Salk’s Gene Expression Laboratory, led a team that worked with stem cells to cure mitochondrial encephalomyopathy and Leigh Syndrome, types of mitochondrial disorders that severely affect the brain and muscles (Belmonte 2015). He collected skin samples from patients with the aforementioned diseases.
First, Belmonte turned skin cells into stem cells by using a process to genetically modify cells to behave like embryonic stem cells. In other words, the skin cells were turned back in time to their most basic state, the pluripotent stem cell state, in which stem cells have the ability to differentiate into any type of cell. During this process, if the patient has both healthy and unhealthy mitochondria, healthy stem cells and mutated stem cells will be created. Then, healthy stem cells can be isolated to use in treatments. If the patient does not have healthy mitochondria, stem cells with healthy mitochondria cannot be generated. In this case, the nucleus of the patient’s mitochondria is moved into a donor egg with healthy mitochondria. Then, the new cell will become pluripotent stem cells with healthy mitochondria. When researchers mixed these healthy stem cells with the patient’s stem cells, they found that healthy stem cells took over and the patient’s cells were able to generate healthy stem cells (Belmonte 2015).
Figure 1- Pluripotent stem cells can be differentiated into any type of cell such as neural progenitors (left) and heart cells (right).
Healthy stem cells generated by Belmonte’s team can be converted into any type of cell that the team wants, as shown in Figure 1. For example, the team could turn healthy stem cells into heart cells, eye cells, brain cells, and more (Belmonte 2015). However, turning these stem cells into mature cells and transplanting them back into patients’ bodies is still under research.
There are strict restrictions on embryonic stem cell research so there is less known about embryonic stem cells. Using stem cells from embryos is controversial for being unethical by some religious communities (Annas 1999). In addition, embryonic stem cells that are generated by research cannot be applied to actual embryos. However, they can be studied by turning somatic cells into pluripotent stem cells, which are not the same as embryonic stem cells, but have similar qualities such as the ability to regenerate indefinitely (Takahashi 2007). Pluripotent stem cells can be used to study disease mechanisms, such as why a disease affects different organs in different ways by turning pluripotent stem cells into different types of cells (Belmonote 2015). In addition, they can be used to screen drugs and treat patients with various types of diseases like juvenile diabetes (Takahashi 2007). There is a lot of potential in using stem cells to find cures for genetic disorders.
Works Cited
Annas GJ, Caplan A, Elias S. Stem cell politics, ethics and medical progress. Nat. Med. 1999; 5: 1339.
Belmonte J, Ma H, Folmes C, Wu J, Morey R et al. Metabolic rescue in pluripotent cells from patients with mtDNA disease. Nature 2015; 524: 234-238.
Sadun AA, Carelli V. The role of mitochondria in health, ageing, and diseases affecting vision. British Journal of Ophthalmology 2016; 90(7): 809-810.
Takahashi K, Tanabe K, Ohnuki M, Narita M et al. Induction of Pluripotent Stem Cells From Adult Human Fibroblasts by Defined Factors. Cell 2007; 131(5): 861-872.
Wallace DC. A mitochondrial bioenergetics etiology of disease. J Clin Invest. 2013; 123(4): 1405-1412.
