Stem Cell Niches, Stem Cell Activation, and Superman
A reader of our blog posed a very interesting question having to do with stem cell activation. Briefly put,
“Why do you need to inject stem cells into an area if the normal tissues in that area already have some stem cells present?”
To understand why, we will talk about two concepts with adipose derived stem cells: the stem cell niche, and stem cell activation . Adipose stem cells are stem cells that are derived from your own fat tissue. They will play a big role in the new field of Regenerative Medicine.
The Stem Cell Niche
Stem cells usually exist in a low grade resting state in a controlled environment called a niche. The niche contains mesenchymal stem cells, also known as MSCs. The mesenchymal stem cell niche is usually located in the blood vessel wall itself.
The status quo for a niche is not full blown stem cell activity, but a level of activity finely attuned to its surroundings. These cells like to keep a stable environment (on the vessels) within the niche. They will only respond in a very specific way, to certain kinds of stimuli.
In a chronic disease state such as scar tissue or aged skin, the stem cells present in that tissue are responding in many small and measured ways to whatever is happening in the tissue. Stem cells like to maintain balanced conditions, also known as homeostasis. With chronic conditions there are no big changes, just a low-grade adaptation to aging or scar process. This is why the stem cells in the local tissue are not doing what you would like them to do. To get a stem cell to do what you want it to do, something else needs to happen. It needs to get activated.
Stem Cell Activation
How do adipose stem cells get activated? For a stem cell to shed its Clark Kent persona and become the activated Superman cell we need, there has to be a major signal. This major signal can be chemicals present in the tissues (cytokines) or coming from afar (hormones), or a mechanical force.
The cell then literally flies out of Clark Kent’s desk (niche) in its shiny new Superman uniform to do whatever is to be done, wherever it is needed. Fat harvesting, centrifugation and fat injections provide such a signal. The liposuction used to obtain tissue is a huge disruption signal, which in turn releases cytokines that augment the signal to activate. After fat is extracted with liposuction, the adipose tissue is then processed with centrifugation techniques. The centrifugation process is a mechanical stimulus that helps separate healthy cells from injured ones, but may also stimulate stem cells.
When you finish processing your fat graft you have a psyched up, ready to go, super-powered population of stem cells ready to go to town. As you inject them to the tissues, they literally do whatever is needed, wherever it is needed.
Fat harvesting, centrifugation, and fat injections provide an activation signal for stem cells.
The challenge for us practitioners and researchers is to understand how this process works. But make no mistake; stem cells are very effective in reversing chronic scarring processes and making skin look younger. My particular research interest is one of the small cytokine molecules that stem cells use to communicate with each other and stimulate growth.
Once stem cells have done their repair and rejuvenation job, they like to revert to their Clark Kent persona and settle into a new niche in the improved tissue environment. And that is a beautiful thing.
Posted in Fat Stem Cells