Arguably, age-related joint issues are where comparatively simple, first generation stem cell therapies have so far had their greatest and most reliable impact. To pick one example, mesenchymal stem cell therapies effectively reduce chronic inflammation for an extended period of time, achieving this result via the signals secreted by the transplanted stem cells in the comparatively short time they remain alive in the patient. Since arthritis is an inflammatory condition, and given that chronic inflammation interferes in the processes of healing, a reduction may spur some degree of increased tissue maintenance activity and repair. Reports suggest that this consequent regeneration is a lot less reliable than the reduction of inflammation, however.
Osteoarthritis (OA) is a prevalent debilitating joint disorder characterized by erosion of articular cartilage. The degradation of network of collagen and proteoglycan in OA cartilage leads to a loss in tensile strength and shear properties of cartilage. Interestingly, though OA manifests as loss of the articular cartilage, it also includes all tissues of the joint, particularly the subchondral bone. Besides aging, the increase in level of accumulation of advanced glycation end products (AGEs), oxidative stress, and senescence-related secretory phenotypes are a few reported factors associated with pathogenesis of OA.
The potential of stem cells to differentiate into osteoblasts, chondroblasts, and adipocytes, if stimulated properly, can regenerate cartilage both in vivo and in vitro. Recent progress in tissue engineering has highlighted the regenerative potential of stem cells for therapeutic purposes. The multilineage potential of stem cells, suitable scaffolds, and appropriate chondrogenic agent (chemical and mechanical stimuli) have been implicated to regenerate damaged cartilage. Mesenchymal stem cell (MSC) based therapy is also emerging as alternative to joint replacement with prostheses, due to its long-lasting effect.
MSCs derived from bone marrow (BMSCs) are capable enough to differentiate into tissues such as bone and cartilage and mobilize at an injured cartilage site in knee joints thereby assisting in cartilage regeneration in OA. In a study, the intra-articularly transplanted BMSC successfully regenerated injured cartilage in an animal model of OA and also improved osteoarthritic symptoms in humans without any major side effect even in the long-term. This study demonstrated the possibility of intra-articular injection of MSCs for the treatment of injured articular tissue including anterior cruciate ligament, meniscus, or cartilage. Therefore, if this treatment option is well-established, it may be minimally invasive procedure compared to conventional surgeries.