Articular Cartilage Regeneration in Veterinary Medicine.

Cartilage is an avascular tissue with a limited rate of oxygen and nutrient diffusion, resulting in its inability to heal spontaneously. Articular cartilage defects eventually lead to osteoarthritis (OA), the endpoint of progressive destruction of cartilage. In companion animals, OA is the most common joint disease, and many pain management and surgical attempts have been made to find an appropriate treatment. Pain management of OA is usually the first choice of OA therapy, which is often managed with nonsteroidal anti-inflammatory drugs (NSAIDs). To avoid known negative side effects of NSAIDs, other approaches are being considered, such as the use of anti-nerve growth factor monoclonal antibodies (anti-NGF mAB), hyaluronic acid (HA), platelet-rich plasma (PRP), and mesenchymal stem cells (MSCs). The latter is increasingly being recognized as effective in reducing or even eliminating pain and lameness associated with OA. However, the in vivo mechanisms of MSC action do not relate to their differentiation potential, but rather to their immunomodulatory functions. Achieving actual regeneration of cartilage to prevent OA from developing or even revert already existing OA condition has not yet been achieved. Several techniques have been tried to overcome cartilage's inability to regenerate, from osteochondral transplantation, autologous chondrocyte implantation (ACI), and matrix-induced ACI (MACI). Combinatory use of MSCs unique features and biomaterials is also being investigated with the aim to as much as possible recapitulate the native microenvironment of the cartilage, yet so far none of the methods have produced reliable and truly effective results. Although OA, for now, remains an incurable disease, novel techniques are being developed, rendering hope for the future accomplishment of actual cartilage regeneration. The aim of this chapter is firstly to summarize known and developing pain management options for OA, secondly to present surgical attempts to regenerate articular cartilage, and finally to present the attempts to improve existing regenerative treatment options using mesenchymal stem cells, with the vision for the possible use of developing strategies in veterinary medicine.