Bone, Cartilage, and Soft Tissue Disorders

Abstract

In most rheumatic diseases, the homeostasis of bone formation and degradation is disrupted through different mechanisms driven by inflammatory mediators, biomechanical factors, and genetic abnormalities. Osteoarthritis is one of the leading causes of disability in adults worldwide. It is a degenerative disease of the joints secondary to many predisposing factors, most notably age, joint injury, altered mechanical stress, and obesity. All these processes cause a local chronic inflammatory response resulting in the progressive joint failure characteristic of OA. Osteoporosis is the result of cumulative bone loss during aging. Nevertheless, a wide variety of diseases, medications, and lifestyles can cause or contribute to the development of osteoporosis. In addition, the immune system participates in the regulation of bone homeostasis through production of cytokines and inflammatory mediators with subsequent activation of cartilage-degrading proteinases. Paget’s disease is a chronic skeletal disorder, caused by enhanced bone resorption followed by abnormal bone formation, in which a potential cross talk between the bone and the immune system takes place.

Hereditary connective tissue diseases (e.g., Marfan’s syndrome, Ehlers-Danlos syndromes, osteogenesis imperfecta) are a heterogeneous group of disorders that result from genetic defects that alter the quantity or structure of extracellular matrix proteins. These disorders can present with various clinical manifestations involving the musculoskeletal, cardiovascular, respiratory, and ocular systems.