In This Issue

Intra-articular NGF Induces Osteoarthritic-Like Pathology Nerve growth factor (NGF) receptors are broadly expressed in joints, known to play a role in pain production and sensitization, and found at increased levels in joints with osteoarthritis (OA).Beyond this, relatively little is known about NGF's actions on joint tissues.In this issue, Obeidat et al. (p.2246) report that introducing exogenous NGF into naïve mouse knees induced many pathologic changes observed in OA, including knee swelling and synovitis.Repeated NGF injections led to profound structural and neuronal remodeling across multiple joint tissues that mimicked OA-like changes.NGF induced widespread synovial pathology as well as robust growth of nociceptors in the medial, but not the lateral, synovium, with neoinnervation in the deeper synovial layers.Newly sprouted synovial