AMYLOID-ASSOCIATED CONDITIONS AS AN AGGRAVATING FACTOR IN ENTHESOPATHIES: A CONCEPTUAL THEORY

Amyloidoses are a group of conditions in which extracellular amyloid deposits (misfolded proteins) are present in the form of fibrils. A special Congo red stain is used for their detection. Amyloid deposits are frequently found in periarticular tissues across various disease entities, and their clinical interpretation is essential: transthyretin amyloid (ATTR) in the carpal tunnel may serve as an early marker of future ATTR cardiomyopathy; a persistent focus of chronic inflammation (e.g., chronic osteomyelitis) is associated with a risk of AA amyloidosis, including cardiac involvement; bacterial amyloids (curli) are considered potential factors that sustain inflammation and initiate amyloidogenesis in periarticular tissues. The concept of amyloid-associated conditions highlights the role of amyloid infiltration of periarticular tissues in the pathogenesis of enthesopathies and the impact of dysproteinosis on extracellular matrix properties and persistent enthesis remodeling. The early detection of amyloid in surgical biopsies of periarticular tissue has practical significance: its presence should be considered as a “warning sign” requiring mandatory subtyping of the modern proteomic techniques (including LC-MS/MS). This approach improves the accuracy of early diagnosis of ATTR and AL variants of cardiac involvement prior to clinical manifestation of the disease and influences the further treatment strategy for the patient.