The incretin-joint axis: weight-independent mechanisms and disease-modifying potential in chronic arthropathies.

Chronic arthropathies are major drivers of pain and disability, and an immunometabolic template is reshaping how osteoarthritis (OA) and inflammatory arthritis are conceptualized, linking systemic metabolic stress to synovial inflammation, cartilage catabolism and disease progression. Incretin-based therapies (GLP-1RAs and dual GLP-1R/GIPR agonists) have revealed pleiotropic actions extending beyond weight loss and glycaemic control, supporting the concept of an 'incretin-joint axis' with disease-modifying potential. Joint tissues appear capable of sensing incretin signalling, supporting a direct, receptor-mediated action within the joint. Across articular cell types, GLP-1RA exposure engages conserved stress-response pathways, reducing inflammation and catabolism in chondrocytes and modulating synovial fibroblast and macrophage activity in inflammatory arthritis. Early clinical data indicate improvements in OA symptoms with GLP-1R agonism; however, mechanistic attribution remains intertwined with weight reduction. Definitive translation will require receptor-centric mapping in human joint microenvironments and interventional designs disentangling direct joint actions from weight-mediated benefit.