What are stem cells?
Although loosely thrown around, the term “stem cells” can actually mean several different types of cells. There are embryonic stem cells, adult stem cells (autologous and allogeneic), induced pluripotent stem cells, hematopoietic stem cells, etc. We are going to focus on human adult Mesenchymal Stem Cells (MSCs). Currently, there is even controversy over the name mesenchymal stem cells. Some argue the in vivo affects are more related to paracrine factors so the name medicinal signaling cells are more appropriate or MSCs are also sometimes called mesenchymal stromal cells based on where they are found. 1 None the less, these “MSCs” can be found in most tissues and serve as local “repairmen” for damaged or aged tissues. MSCs are multipotent cells that initiate repair and replace damaged cells in our body. Every tissue in our body has stem cells and they are primarily responsible for maintaining the health of our tissues so if we didn’t have these cells we could not keep up with the daily stress our body takes and we would die.
Two characteristics that are unique to stem cells are: one, they are capable of self- replication and two, they can differentiate into different cell types. To identify stem cells, the International Society for Cellular Therapy (ISCT) has developed a position statement for the minimum classification requirements for a cell to classified as an MSC. 2
Stem cells for orthopedic use
For orthopedic purposes we can most commonly obtain MSCs from the bone marrow or adipose tissue. Current regulatory guidelines by the FDA classify bone marrow procedures as only 100% compliant source of stem cells utilized for orthopedic conditions.3,4 This is a procedure where bone marrow is aspirated from the iliac crest (most commonly) and the nucleated cell fracture that has containing stem cells and other cellular material is concentrated and extracted for therapeutic purposes. Also note that there are no true orthopedic stem cell procedures in the US involving birth tissues such as amniotic fluid, amniotic membrane, chorion, Wharton’s jelly, or umbilical cord blood. These off the shelf allogenic products do NOT have live and functional stem cells and even if they did it would be illegal to use those cells.5
Cultured stem cells
For cultured MSC therapy, bone marrow is concentrated but then one isolates and grows those MSCs out in culture media and autologous platelet lysate. The result is to take the relatively small number of MSCs found in a sample bone marrow, (10,000 to 1million) and expand them to a population of 10 – 100+ million cells. This process takes 2-4 weeks. In general, the theory is that the more MSCs used, the more potential for regeneration and the higher ability to treat more areas. However, based on FDA guidelines since then, these cultured MSCs are classified as a drug and are not currently approved in the U.S. Thus, this therapy is only available in a few countries outside of the U.S. At the time of writing there are 2 companies in clinical trials using autologous cultured cells for degenerative disk disease and the other using allogeneic MSCs for degenerative disk disease. Pending the completion and results of those studies, possible FDA drug approval for cultured stem cells to treat degenerative disk treatments may come to fruition in the U.S?
Clinical Research on non-cultured stem cells
At this time, there is still a long way to go with publishing research utilizing non-cultured stem cells, but there is already greater than 100 human clinical research studies showing autologous bone marrow MSC therapy can help improve pain and function for various orthopedic problems. In regards to safety of bone marrow procedures for MSK treatments, there are 2 large safety papers showing no risk of tumors and rare serious adverse events much less than typical orthopedic surgeries.6,7 (,) There have also been other studies demonstrating efficacy for the treatment of shoulder arthritis and rotator cuff tears8,9, hip arthritis10, knee osteoarthritis11, ankle arthritis12, thumb arthritis13, ACL tears14, degenerative disc disease15, nonunion fractures16, surgical augmentation for rotator cuff repair and spinal fusion17, also, hip and knee avascular necrosis18.
The Up-Side
We are here to guide you through the maze of misinformation that exists regarding stem cell treatments! Armed with accurate information you can make best available clinical decisions to provide your patients with the options and information they deserve.