Dr. Warner here –
Stem cells are called ‘stem’ for a simple reason: from the stem may come various branches.
In the case of a stem cell, once the type of branch is chosen, the stem cell can actually produce new tissue of that type. For example, if stem cells are implanted into bone, they usually produce bone-forming cells (osteoblasts), and these then make new bone. If stem cells are implanted into a joint (knee, hip, ankle, etc.), then they usually produce chondrocytes (cartilage-forming cells) and are then able to create new cartilage.
The question is, how do they do this?
The Assignment of Mesenchymal Cells
Mesenchymal stem cells (MSCs) are found in babies and adults. These are cells that are held in reserve for the purpose of growth, repair, and renewal. As we age, we have fewer and fewer of these. MSCs are found in tissue of mesoderm origin such as muscle, bone, tendon, adipose, and liver.
Specification of what type of tissue the MSC becomes relies on transcription factors turning on certain enhancer units on the MSC DNA. These transcription factors are themselves regulated by diet, lifestyle, environment, and genetics.
How Mesenchymal Cells Function
It is thought that the surrounding tissue type actually produces biochemical signals that also induce the MSC one way or another. Thus, by implanting stem cells into a joint it is not likely to become anything but cartilage.
Once a stem cell has been specified to a particular lineage it then differentiates into that type of cell. The effectiveness of the new cell is variable as well. It can be very productive or not as effective. At that point, the regeneration of that tissue type may begin.
The body does not produce an unlimited number of stem cells. Each regional tissue type does have its own stem cells, however. The goal of regenerative medicine is to implant a large concentration of stem cells into the diseased tissue area. This supraphysiologic load of new cells then allows for tissue regeneration that would not occur otherwise.
For more information regarding mesenchymal cells or to learn if this treatment would be beneficial for you, contact us today at Warner Orthopedics and Wellness!
Meredith Warner, MD
