An injectable thermosensitive hydrogel delivering M2 macrophage-derived exosomes alleviates osteoarthritis by promoting synovial lymphangiogenesis

Osteoarthritis (OA) is a prevalent chronic degenerative disease affecting millions worldwide, with current treatment measures lacking efficacy in slowing disease progression. The synovial lymphatic system (SLS) has emerged as a crucial player in OA pathogenesis, with compromised drainage function contributing to disease advancement. Lymphatic endothelial cells (LECs) within the SLS are influenced by synovial macrophages, whose precise impact on LEC function remains unclear. Exosomes released by macrophages may serve as mediators of this interaction, with potential implications for OA progression. Here, we propose that polarized macrophages modulate LEC activity via exosome release in synovial tissue, with M2 macrophage-derived exosomes (M2