Cellular and Molecular Homeostatic Microenvironmental imbalances in Osteoarthritis and Rheumatoid Arthritis

Human movement is a complex and multifactorial process due to the interaction between the body and the environment. Movement is the result of activities of all the structures that make up a joint (i.e., ligaments, tendons, muscles, fascicles, blood vessels, nerves, etc.) and of the control actions of the nervous system on them. Therefore, many pathological conditions can affect the Neu-ro-Myo-Arthro-Kinetic System (NMAK). Osteoarthritis (OA) is the degenerative form of arthritis with a high incidence and a pro-longed course that affects articular and periarticular tissues such as articular cartilage, subchondral bone, and synovium, a degen-erative consequence. Instead, Rheumatoid arthritis (RA) is an immune-mediated synovial disease caused by a complex interaction between genetic and environmental factors. This review aims to compare Osteoar-thritis (OA) and Rheumatoid Arthritis (RA) in terms of pathogenesis and microenvironment and determine the main changes in a joint microenvironment regarding immunological defense elements and bioenergetics which can explain the pathological development with new thera-peutical opportunities. Keywords: Osteoarthritis (OA); Rheumatoid arthritis (RA); Homeostatic imbalances; Microenvironment