Stem cells have become a “trend word” recently due to their promising role in healthcare. Stem cells are present in all animals, they exist along with normal cells but they have some unique differences. When cells in your body die, they get replaced by stem cells, those cells divide as needed, one differentiates, takes up a role and the other one becomes a stem cell for future use. It is a great system to keep us alive and well.
But this has some issues. Stem cells cannot divide indefinitely, they have a certain number of divisions and they work under very specific signals that are yet poorly understood.
Molecules basically trigger processes in a stem cell to differentiate. At the same time we have developed methods to make stem cells out of normal adult tissues, basically turn differentiated cells into stem cells. The best example is the Yamanaka factors, a set of transcription factors that instruct a cell to become an induced pluripotent stem cell (IPSC).
So lets do it, take adult cells and turn them into stem cells, then use them to replace exhausted or diseased stem cells in old and/or sick people.
As with most things, it is not that simple. BUT there have been some great studies lately indicating the progress in this field.
As we investigate this area of biology, we find more genes that are involved in cell proliferation and differentiation. A study published in 2018 found that basal cells in the lungs express genes seemingly necessary for H1N1-response. This shows that viruses may have evolved to take advantage of such cell lineages. Or it can simply mean that stem cells will constitute a cure for another type of disease in the future (viral infections).
Other studies have shown that stem cells continuously lose their “powers” as we age. There are many people interested in the potential to extend the lifespan of humans by periodically replacing stem cell pools in our bodies. Aubrey de Grey thinks that this may be possible within the next 50 years. While that would seem optimistic, there is a lot of interest in this field from young, motivated scientists, a lot of funding and the fact that researching stem cells and cancer is pretty similar.
Cancer cells, like stem cells can divide infinitely. The difference is that stem cells require specific signals, can die under harsh conditions and infinitely for them is more like “many times”, meaning there is a limit. Cancer cells on the other hand don’t care about any conditions or signals. They just divide until the organism they live in dies. It is very hard to treat cancer but by studying stem cells we may be able to find out how cells divide so much and differentiate and how to they stop dividing.
Stem cell transplants have delivered excellent results in many studies on many pathologies. The potential appear to be huge, and still while progress is steady we need to learn a lot more. Transplants of stem cells have been delivered and worked in eyes, brains, muscles and bones.
Then the thing that remains unclear is how long do we have until we can get a treatment to regenerate a new healthy heart or lung.
Finally i want to say that i stayed away from the technical, protein, gene stuff in this article to keep it simple for everyone. My goal was to inform people with up to date data on how successful stem cells are in 2018. If you would like such an article though, one explaining the specifics behind stem cells, and where does the latest research focus let me know in the comments or on twitter.
Sources: Differentiation and Transplantation of Embryonic Stem Cell-Derived Cone Photoreceptors into a Mouse Model of End-Stage Retinal Degeneration
Is there a place for human fetal-derived stem cells for cell replacement therapy in Huntington’s disease?
Translation of WNT developmental programs into stem cell replacement strategies for the treatment of Parkinson’s disease
Muscle Stem Cells Exhibit Distinct Clonal Dynamics in Response to Tissue Repair and Homeostatic Aging
Spatial-Temporal Lineage Restrictions of Embryonic p63+ Progenitors Establish Distinct Stem Cell Pools in Adult Airways