11 Apr Adipose Tissue-Derived Stem Cells for Osteoarthritis
Adipose tissue-derived stem cells (ASC) are pluripotent stem cells extracted from the fat deposits of adults. They are extracted in the form of stromal vascular fraction (SVF) and then expanded in culture. Among other indications, ASC can potentially be used in the treatment of osteoarthritis (OA).
ASC has been shown to successfully induce cartilage-like tissue regeneration. Many centers have performed research on finding optimal ways to administer ASC and to maximize their therapeutic effect against OA. Current medical treatment for OA and other musculoskeletal diseases, such as degenerative joint disease are limited to symptomatic therapy, including nonsteroidal anti-inflammatory drugs (NSAIDs), hyaluronic acid (HA) joint injections, physical therapy, steroid injections, etc., which do not address the underlying cause. When these nonsurgical symptomatic treatment options fail, surgical options such as knee arthroplasty are the last resort. They carry relatively high risks of morbidity and mortality, with up to 5.6% of the patients who underwent surgeries developing complications.
Now, through ASC-induced cartilage regeneration, we have a shot at curing OA. ASC is a type of mesenchymal stem cells (MSC) that are derived from fat tissue, and have the capability to differentiate into various tissues, including cartilage. ASC (in SVF) can be mixed with platelet-rich plasma and hyaluronic acid and injected as cocktail into the diseased knee via percutaneous intra-articular injection. As more data accumulates, the mechanisms of cartilage regeneration by ASC/MSC are gaining much attention as a viable curative process in patients with OA.
How the ASC actually lead to cartilage or any tissue regeneration is poorly understood – is it the actual engraftment of these stem cells that replace damaged cells or release of trophic/growth factors that lead to endogenous growth, or some combination of the two? It should be noted that even in the best circumstances, the ASC administration has not led to a full amount of growth of cartilage to a normal, nondegenerated state. This is possible because of the limited number of viable chondroblasts and chondrocytes in the damaged cartilage tissue that could be influenced by ASC to heal.
If having large quantities of ASC can fix this problem, ASC can be produced in very high yields. One gram of adipose tissue may yield up to 2,000,000 nucleated cells, of which 1% to 10% is considered to be ASC. So there is always a sufficient number of ASC that can be provided to treat OA with an adequate amount of adipose tissue. Producing a high number of stem cells also leads to a higher yield of growth factors, in turn, stimulate stem cells to grow within the joint for better cartilage regeneration. Coadministering with HA and PRP provides even more support for proper tissue infrastructure that leads to better healing and regeneration.
Overall, while there are gaps in the full understanding of how ASC work, this form of adult stem cell therapy holds great promise in curative management of OA, as it is ethical, efficacious and “scalable”. As more research accumulates to establish its safety and efficacy profile, we hope to see it become a clinically available treatment for OA in the near future.