MMP1 and osteoarthritis: Omentin, in particular, decreases the release of inflammatory cytokines such as IL-6; stimulates osteoblast proliferation through the PI3K/Akt pathway [166]; promotes M2 macrophage polarization in osteoarthritis synovial fibroblasts [169]; and inhibits the expression of MMP-1, MMP-3, and MMP-13, helping to prevent further cartilage degradation [170], potentially contrasting OA progression.