Possible morphological substrates in the pathogenesis of arthritis

Abstract

To gain more insight into the morphogenesis of synovial joints, as well as into pathogeneses of joint diseases like Rheumatoid Arthritis (RA) and possibly also Osteoarthritis (OA), we surveyed human finger joint ontogeny from early developmental stages. In adult interphalangeal joints, dorsal and palmar but also ulnar and radial synovial folds do persist. During adult life, synovial membranes as well as synovial folds (e.g., after micro-damage) may elicit chronic inflammatory processes that eventually lead to arthritis. In proximal interphalangeal (PIP) joint proper collateral ligaments (PCL), we found neurofilaments and oval-shaped lamellated corpuscles (ø ≈ 120 µ). Supposedly acting as mechanoreceptors, these may also produce cytokines and substance P, a neuropeptide involved in pain. As the PIP-joints of fingers in particular show symptoms of Rheumatoid Arthritis at early stages, these organs may therefore play a role in the pathogenesis of arthritis.