Stem Cells For Muscle Gains
By Patrick Arnold
What if they could liposuction fat out of you, put it in some machine, and then get super cells out the other end that you could have injected into your muscles to repair injury and possibly cause local growth? It sounds pretty cool doesn’t it? Apparently this is what some new research suggests is possible, and thanks to some recent technological breakthroughs it appears that it might not be too difficult or expensive to do.
You probably have heard of stem cells. Stem cells are a special kind of cell that exist in a sort of “unprogrammed” state. There are many different kinds of stem cells that can be derived from many different tissues, but the fundamental property they all have is a varying ability to differentiate from their primordial state into cell types of all sorts such as blood cells, heart muscle cells, bone cells, organ cells, brain cells etc.
The most useful stem cells are those derived from embryos and they are known as “pluripotent” stem cells. That basically means they have the ability to differentiate into any cell type in the body. Due to ethical concerns, and the obvious raw material limitations of harvesting embryos, this sort of stem cell does not enjoy practical exploitation in medicine. There are also stem cells that can be harvested from adult tissues. Although adult bodies primarily consist of fully differentiated cells that serve our various needs, there also are stem cells present. Adult stem cells are known as multipotent stem cells. They don’t quite have the flexibility to easily morph into anything like embryonic stem cells do, but they can be coaxed to differentiate into lots of useful cell types. And of course they don’t share the controversy and limitations associated with embryonic stem cells.
Blood marrow has been one such important source of multipotent adult stem cells for medical research and application in the recent past. As useful as bone marrow is however, the process of drilling into your bone to suck out the marrow is invasive and distasteful. Thankfully, in recent years it has become apparent that fat stores harbor an impressive variety of adult stem cells as well (reportedly containing 100-300 times as many useful cells as blood marrow).
Fat stores are easily accessible. Cosmetic surgeons suck out pounds of the stuff every day from women’s hips and men’s bellies and then proceed to chuck it all in the medical waste bin. Adipose tissue derived regenerative cells (ADRCs) as they are called can be isolated from all this waste fat, however until recently the process has been less than rapid and practical because it involves a prolonged culturing period. Luckily, a new filtering system has been developed which rapidly separates out the ADRC fragments of the fat and dumps out all the needless junk. [ADRCs by the way consist partly of adipose tissue derived stem cells as well as other progenitor cells of value to injury repair such as vascular related endothelial cells, fibroblasts, and preadipocytes.]
In recent years there have been some interesting studies performed using ADRCs in muscle tissue. In one study, the cells were injected into mice with muscular dystrophy and the muscle strength and resistance to fatigue improved http://www.ncbi.nlm.nih.gov/pubmed/21874281. In another, the cells were injected into normal mice and new muscle tissue was observed to be formed at the injection site http://www.ncbi.nlm.nih.gov/pubmed/16887099. Just recently though a study was released looking at the effect of ADRCs on muscle tissue injury in mice, and the mechanisms of the actions were examined in more detail then in the previous studies http://www.ncbi.nlm.nih.gov/pubmed/23239611.
In this study rats had their tibialis anterior muscles lacerated with a scalpel. One group had a simple phosophate saline solution injected at the site, a second group had human bone marrow stem cells injected, while a third were injected with human ADRCs. The rats injected with ADRCs showed greatest improvement in healing out of the three groups. The formation of new blood vessels (angiogenesis) and new muscle cells (myogenesis) was observed, and fibrosis was suppressed.
The researchers looked to see exactly what was going on. Since the rats were injected with human progenitor cells they could examine certain markers to see if these cells were differentiating into muscle and vascular cells in the rats. Although that was observed to a small degree, it appeared that what was mostly going on was that these injected cells were secreting lots of cytokines and growth factors such as vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF), and these were stimulating the rapid repair and regrowth of the native tissue in the injection area.
Whatever the mechanism, the technique seems to have potential due to its ease of preparation and also due to the low risk of immune rejection (since one’s own cells are being reinjected into their body). Also, we don’t know whether if when human ADRCs are injected into human tissues there may be more actual differentiation into new tissue going on, and not just mostly paracrine stimulation of growth of existing tissue from secreted growth factors.
I expect to see this technique to soon gain popularity in elite sports injury repair along with current new fangled techniques such PRP injections.