Adaptive Stem Cell Therapy: The Future of Regenerative Medicine

Written by Sarah Wornow ‘23
Edited by Geat Ramush ‘23

Stem cell therapy is an emerging field of regenerative medicine that has the potential to completely change the standard of care for major diseases. This type of therapy can be utilized in various ways, including repairing any type of diseased or damaged tissue within the body, studying how diseases affect certain tissue types (which leads to more precise drugs being developed for specific diseases), and testing newly discovered drugs in the context of the tissues they will affect [1]. 

There are three types of stem cells in current use: embryonic stem cells, induced pluripotent stem cells (iPSCs), and adult stem cells. Embryonic stem cells are harvested during embryonic development and have the ability to specialize into any type of cell within the body. They are primarily used for research purposes to gain insight into human development and to test new drugs due to their ability to differentiate into any cell type [4]. iPSCs are derived from skin or blood cells and are reprogrammed into an “embryonic-like” state, meaning they can also differentiate into any type of cell within the same developmental layer. They have been used for various therapeutic purposes, including treating musculoskeletal diseases and blood disorders [5]. Adult stem cells are harvested during adulthood and have the ability to differentiate into any cell type within a particular tissue where they are located [2,3]. They have similarly been used to treat diseases, most frequently in bone marrow transplants and neurodegenerative diseases [6]. Various degrees of success have been achieved through utilizing these types of stem cells.

Current stem cell technologies, while amazingly complex and beneficial, have some important limitations. First, utilizing embryonic stem cells requires harvesting these cells from live embryos, introducing ethical and religious concerns. iPSCs have a limited range of tissues they can differentiate into, must be differentiated before being used to treat a patient, and can’t be directly injected into a patient due to the risk of a tumor developing [7]. Lastly, adult stem cells are extremely limited in a fully developed human, making the collection of these cells difficult. 

A new type of stem cell was recently developed by a group at the UNSW Sydney that solves many of these issues. Known as induced multipotent stem cells (iMSCs), these cells are taken from human fat cells, also called adipocytes, and reprogrammed into undifferentiated stem cells. Similar to wiping a computer’s memory, the fat cells are treated with various chemicals to “wipe” their genetic memory and erase silencing marks on genes that would determine what kind of cells they would eventually develop into. The researchers first studied these cells on grafts of various types of mouse tissue. The cells properly differentiated into the tissue type that was placed near them, whether that be bone, cartilage, muscle, or blood vessels. Next, the cells were injected into mice who had no muscle injury. The iMSCs stayed dormant and didn’t accumulate or develop into a tumor, as seen when iPSCs are directly injected into patients, until a muscle injury was induced by the researchers. Then, the cells differentiated properly into the appropriate muscle tissue and healed the tissue. These results are promising for a number of reasons, as these new types of cells have no ethical concerns (they can be harvested directly from patients’ fat cells), do not have to be differentiated before injection (they differentiate within the body), can develop into many different cell types depending on their surroundings, and don’t uncontrollably divide to produce tumors. 
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iMSCs have the potential to completely change the field of regenerative medicine. Any type of injury, including heart damage, muscle sprain, or neurodegenerative disease, can potentially be treated with these types of stem cells. However, both preclinical and clinical trials have to be completed before any type of therapy can be utilized by patients, meaning that the use of these cells is a long way off. Still, iMSCs are paving the way to a world where a patient facing a severely debilitating disease can be cured using their own fat cells.

References
[1] Stem Cells: What They Are and What They Do. Mayo Clinic [Internet] [Cited 2021 Feb 10]. Available from: mayoclinic.org/tests-procedures/bone-marrow-transplant/in-depth/stem-cells/art-20048117

[2] Induced Pluripotent Stem Cells (iPS). UCLA Broad Stem Cell Research Center [Internet] [Cited 2021 Feb 11]. Available from: https://stemcell.ucla.edu/induced-pluripotent-stem-cells

[3] Aly R. Current State of Stem-Cell Based Therapies: An Overview. Stem Cell Investigation. 2020; 7, 8. [Cited 2021 Feb 11]. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7367472/

[4] Yu J, Thomson J. Embryonic Stem Cells. National Institutes of Health [Internet] [Cited 2021 Feb 11]. Available from: https://stemcells.nih.gov/info/Regenerative_Medicine/2006Chapter1.htm#:~:text=The%20ES%20cell%2Dderived%20cells,disease%20or%20spinal%20cord%20injury.

[5] Singh V, Kalsan M, Kumar N, Saini A, Chandra R. Induced Pluripotent Stem Cells: Applications in Regenerative Medicine, Disease Modeling, and Drug Discovery. Frontiers in Cell and Developmental Biology. 2015; 3, 2. [Cited 2021 Feb 11]. Available from:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4313779/

[6] How Are Adult Stem Cells Turned into Treatments? Boston Children’s Hospital [Internet] [Cited 2021 Feb 11]. Available from: http://stemcell.childrenshospital.org/about-stem-cells/adult-somatic-stem-cells-101/how-do-adult-stem-cells-get-turned-into-treatments/

[7] University of New South Wales. A Step Closer to Developing “Smart” Stem Cells- Cells With Regenerative Abilities- Made From Human Fat. SciTechDaily [Internet] [Cited 2021 Feb 11] Available from: https://scitechdaily.com/a-step-closer-to-developing-smart-stem-cells-cells-with-regenerative-abilities-made-from-human-fat/

[Image Citation] https://pixabay.com/illustrations/cells-human-medical-biology-health-1872666/