Growth factors fall under the category of regulating cartilage catabolism and anabolism, playing a “significant role in musculoskeletal tissues’ homeostasis and repair,” Dr. Hunter explained. “They influence chemotaxis, differentiation, proliferation, and synthetic activity of cartilage and bone cells, and can regulate physiological remodeling and cartilage healing.”
Examples of growth factors of interest in OA include transforming growth factor-beta superfamily and bone morphogenic proteins 2 and 7, fibroblast growth factors 2 and 18, and insulin-like growth factor-1.
Two currently unproven and somewhat controversial ways of regulating cartilage catabolism and anabolism is the use of mesenchymal stem cells (MSCs) and platelet-rich plasma (PRP). Neither are ready for widespread use, Dr. Hunter observed, and more data on these approaches still need to be gathered.
The rationale behind the use of MSCs is that all joint tissues contain these cells, and they can potentially differentiate into cartilage, bone, or other tissues. There are changes in the quantity, phenotype, and differentiation potential of these cells in patients with OA, however, leading researchers to see if intra-articular injection of MSCs could be a possible therapeutic strategy. MSCs can be isolated from a number of different tissues and differentiate into multiple cells types. Animal model data suggest that their transplantation into an affected joint can stimulate articular repair.