Prokineticin 2 and Cytokine Content in the Synovial Fluid of Knee Osteoarthritis and Traumatic Meniscal Tear Patients: Preliminary Results

Knee osteoarthritis (OA) is a chronic degenerative inflammatory-based condition causedby a cascade of different intra-articular molecules including several cytokines. Among the cytokines,prokineticins (PKs) have recently been identified as important mediators of inflammation and pain.This observational study examined the potential involvement of PK2 in degenerative or traumaticknee disease. Fifteen patients presenting knee osteoarthritis (OA group) and 15 patients presenting atraumatic meniscal tear (TM group) were studied. Synovial fluid samples from affected knees wereassessed for PK2, IL-10, and TNF-α using the ELISA method. At a long-term follow-up (minimum5 years, mean = 6.1 years), patients in the TM group underwent clinical re-evaluation with PROMs(Tegner Activity Scale, IKDC, Lysholm, SKV); in addition, X-ray visualization was used to assess thepresence of secondary OA. PK2 was detected in synovial fluids of both TM and OA patients andthe levels were comparable between the two groups, while IL-10 levels were significantly greater inthe OA group than those in TM patients. PK2 levels correlated with those of IL-10. PK2 levels weregreater in blood effusions compared to clear samples, did not differ significantly between sexes, norwere they related to differences in weight, height, or injury (meniscal laterality, time since dosing). Nocorrelation was found between PROMs and radiological classifications in patients in the TM group atfinal follow-up. These data are the first observations of PK2 in synovial fluid following traumaticmeniscus injury. These findings suggest possible further prognostic indices and therapeutic targets tolimit the development of secondary OA.