Stem Cell Therapies in Regenerative Medicine

 Abstract  
 

Stem cell therapies are a rapidly developing treatment of modern regenerative medicine largely due to their ability to repair and regenerate damaged tissues or organs. This article provides a brief overview of the types of stem cells used; their uses and ethical challenges associated with their use.  
 
Introduction  
 

Regenerative medicine is a branch of medicine which aims to repair damaged tissues and organs. Stem cells are a major part of this due to their unique ability to differentiate to any cell in the body, and the ability to divide many times providing a source of healthy cells for uses in treatment (Zakrzewski et al, 2019). Stem cell therapies offer treatment or curing to many degenerative diseases or diseases considered previously incurable, such as Parkinson’s, spinal cord injury or heart failure.  
This article will explain the types of stem cells, their uses and the challenges they present.  
 
Types of Stem Cells  
 
Embryonic Stem Cells (ESCs): stem cells which are derived from early-stage embryos and have plutipotency, the ability to differentiate into any type of cell in the human body. These are considered very effective however their use has been challenged as they involve the destruction of embryos, raising ethical concerns (Lo and Parham, 2009).  
 
Adult Stem Cells: also called somatic stem cells, these cells are found in specific areas of the human body such as bone marrow and can differentiate into a range of cells in the human body, a property called multipotency. For example, haematopoietic stem cells found in bone marrow are capable of differentiating into different types of blood cells (Weissman, 2000). Although less controversial in use, adult stem cells are much more limited in their effectiveness in treatments.  
 
In recent years there have been breakthroughs in creating induced pluripotent stem cells (iPSCs) which are adult stem cells reprogrammed to behave like ESCs stem cells (Takahashi, Yamanaka, 2006). These cells have significant potential in the field of regenerative medicine due to their pluripotent properties alongside much fewer ethical challenges. They can also reduce the risk of the immune system rejecting treatment as iPSCs are derived from the patient's own tissue.  
 
Uses of Stem Cell Therapies 
 
In Cardiology, stem cells have been used to regenerate damaged heart tissue after a heart attack to improve heart function.  
In Neurology, stem cells have been researched to determine whether they can reduce symptoms caused by Parkinson’s disease, aiming to replace lost dopamine-producing neurons (Barker et al., 2018).  
 
These examples display the uses of stem cells in both treatments against degenerative diseases, and in repairing previously incurable damage.  
 
Scientific Limitations and Ethical Challenges 
 
- Controlling differentiation into the desired cell type, avoiding tumor growth and ensuring the cell integrates into the host remains difficult (Trounson, A., & McDonald, C., 2015). 
- The use of ESCs remains controversial as it involves destroying embryos, which some consider to be morally unacceptable (Lo and Parham, 2009).  
-There are availability and economic issues associated with stem cell therapies. Current treatments are still in clinical trial or remain inaccessible financially to most patients.  
 
Conclusion  
 
Stem cell therapies have the ability to transform into regenerative medicine, offering the possibility of treating diseases considered incurable or preventing degenerative diseases. Advances like iPSCs have reduced ethical concerns whilst still providing the same advantages as controversial treatment using ESCs. However, there are still scientific, financial and ethical issues to overcome before stem cell therapies will be available to the masses as an effective treatment.  
 

References  
 
Zakrzewski, W., Dobrzyński, M., Szymonowicz, M., & Rybak, Z. (2019). Stem cells: past, present, and future. Stem cell research & therapy, 10(1), 68. https://doi.org/10.1186/s13287-019-1165-5  
 
Lo, B., & Parham, L. (2009). Ethical issues in stem cell research. Endocrine reviews, 30(3), 204–213. https://doi.org/10.1210/er.2008-0031 
 
Weissman I. L. (2000). Stem cells: units of development, units of regeneration, and units in evolution. Cell, 100(1), 157–168. https://doi.org/10.1016/s0092-8674(00)81692-x  
 
Takahashi, K., & Yamanaka, S. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell, 126(4), 663–676. https://doi.org/10.1016/j.cell.2006.07.024 
 
Menasché P. (2018). Cell therapy trials for heart regeneration - lessons learned and future directions. Nature reviews. Cardiology, 15(11), 659–671. https://doi.org/10.1038/s41569-018-0013-0  

Barker RA, Parmar M, Kirkeby A, Björklund A, Thompson L, Brundin P. Are Stem Cell-Based Therapies for Parkinson’s Disease Ready for the Clinic in 2016? Journal of Parkinson’s Disease. 2016;6(1):57-63. doi:10.3233/JPD-160798 
 
Trounson, A., & McDonald, C. (2015). Stem Cell Therapies in Clinical Trials: Progress and Challenges. Cell stem cell, 17(1), 11–22. https://doi.org/10.1016/j.stem.2015.06.007