Bone marrow and synovial fluid stem cells in vivo as drivers of spontaneous tissue repair
Regenerative Medicine approaches have entered multiple fields of Medicine including Orthopedics, Neurodegenerative Disease, Liver disease and others. Various combinations of scaffolds, growth factors and stem cells have been used to restore the function of failing or missing tissues. For a rheumatologist, osteoarhtiris (OA), a disease that is lacking a cure and representing a significant burden to global economy, is currently seen as a primary target for regenerative approaches. To repair damaged joints in OA is not simply be able to fill-in defects in cartilage; as OA is a disease of the whole joint, a multi-faceted approach, involving better understanding of pain, joint biomechanics, inflammation, bone, cartilage and ligament homeostasis needs to be undertaken. As an important part of Regenerative Medicine triangle, stem cells are key cellular drivers of neotissue formation. Amongst a plethora of numerous stem cell types and lines potentially available to a rheumatologist in the future, the most abundant type amenable to easy harvesting and minimal manipulation are mesenchymal stem cells (MSCs). This presentation will outline recent findings pertaining to characterization of MSCs in human bone marrow (BM) and joint synovial fluid (SF), focusing on their native phenotypes in vivo and potential roles in spontaneous tissue repair.
These two types of MSCs are also the most likely candidate ‘drivers’ of neocartlage formation following microfracture, a common treatment of focal cartilage defects. A better knowledge of joint MSC trafficking in health and post-injury is likely to lead to future improvements in cartilage maturation and long-term survival following this procedure, thus lowering the burden of post-traumatic OA. For large cartilage defects, significant academic and industrial investment remains focused on MSCs or chondrocytes expanded in vitro, however key recent observations on the presence of MSC in cartilage superficial layer and the SF suggest that the use of exogenously added, culture-expanded cells may not be necessary. This talk highlights innovative ideas and animal studies, in which minimal MSC manipulation in vivo has produced good restoration of joint morphology and function. For non-traumatic OA, the understanding of MSC responses to altered biomechanics and inflammation, as well as their routes of migration and homing to damaged tissues, could be the key to the development of novel, faster, minimally-invasive and cost-effective therapies of the future.
Disclosure of Interest None Declared