Prospects of Stem Cell Therapy in Osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis and it affects millions of people on the world. The disease brings about the ultimate destruction of synovial joints. For the patients, quality of life is reduced because of the loss of movement and function and, as the disease progresses, pain from the joint increase to become continuous, even occurring at rest. Underlying the disease is a loss of the normal homeostasis of the joint, generally leading to excessive catabolism relative to anabolism. The arthritic joint can, however, demonstrate apparent repair mechanism, although these often result in overactive but aberrant production of bone and cartilage in the form of osteophytes. OA was previously thought of as a wear and tear process. More recently it has been defined, not as a single condition, but rather a common complex disorder with three groups of risk factors: genetic, constitutional (aging and obesity) and local (biomechanical consequence of joint injury, joint laxity or malalignment). OA is not simply a disease of cartilage destruction but a collection of different pathological processes involving several anatomical parts of the joint with the relationship between the underlying bone and the cartilage being recognized in particular.

Different pathways may be involved at different stages of Osteoarthritis. For example, early in the disease, there is an initial increase in inflammatory mediators, matrix- degrading proteinases and stress- response factors in cartilage, perhaps in response to a mechanical injury.

Why is there a need for Stem Cell Therapy to treat OA? To date it is generally believed that there is little to be gained by surgical intervention before the end stage of disease, when arthroplasty can provide excellent pain relief and functional restoration. The problem with joint replacement is that the implants have a finite lifespan after which a variety of factors, such as wear particle formation, contribute to loosening and, therefore, the prosthesis is likely to require revision surgery. This is more complex, costly and not as successful as the initial treatment in the long term. The use of artificial joint in young patients (i.e. <55 years) is associated with higher failure rate as compared to older patients.

As paradigm for tissue regeneration, Stem cells have been used for many orthopedic conditions, including osteoarthritis treatment. The two principle characteristics of stem cells i.e. the ability to self- renew and to differentiate along multiple lineages make them an attractive option to treat age- related disorders that involve more than once tissue, such as degenerative joint diseases and arthritis. Stem cells with their potential influence on modulating the immune system, present themselves as an interesting choice, particularly when those arthritis have an inflammatory component.