Osteoarthritis is the most common form of arthritis. The Communicable Diseases Center in Atlanta estimates that OA affects more than 27 million Americans. Other estimates tend to run higher. Almost all agree that the incidence is going to climb as a result of the Baby Boomer "epidemic."
There are many symptomatic treatments for OA. These include analgesic medications, topical and oral non-steroidal anti-inflammatory drugs (NSAIDS), physical therapy, exercise, lifestyle modification, bracing, and injections of glucocorticoid or viscosupplements. However, once these fail, there is little else to offer than operative treatment. This is not acceptable.
Recently, there has been increasing interest in the use of mesenchymal stem cells (MSCs) to potentially slow down or even possibly regrow lost cartilage. Animal experiments have been promising and a few anecdotal reports in the literature along with short series have confirmed a possible benefit for humans as well.
Mesenchymal stem cells are sometimes referred to as mesenchymal "stromal" cells because their differentiation is along the lines of stroma or connective tissue.
Among the various tissues, mesenchymal stem cells can evolve into are skin, muscle, bone, cartilage, tendon and ligament, fat, and nerves.
Mesenchymal stem cells are relatively easy to obtain since they are abundant in both the bone marrow as well as adipose fat. MSCs have the ability to differentiate as well as replicate, given the proper environment. This last point is critical to understanding the biology of MSCs.
It is still not known what type of protection MSCs require when exposed to the hostile environment of a joint like the knee, where weight-bearing is such an important task.
It is important to know that a proper stem cell procedure done for OA of the knee involves more than just harvesting stem cells and injecting them into the joint. Selective injury administered to the area requiring repair is absolutely essential. Injury is the first step in healing and is required for stimulation of stem cell differentiation. The extent of injury required is still a subject of conjecture.
Combining ultrasound imaging as well as arthroscopy in order to visualize the area of disease and allow access to it can make the difference between a successful versus an unsuccessful procedure.
On a separate note, MSCs may find usefulness in OA since they do have immunomodulatory effects as well. It is now known that OA is an inflammatory disease that requires disease modification much the same way that RA does. This may be an important component that explains how MSCs work in OA.
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