title: Synovial Fluid Macrophage Migration Inhibitory Factor Levels Correlate with Severity of Self-Reported Pain in Knee Osteoarthritis Patients.
abstract: BACKGROUND Inflammation is considered as one of the main pathogeneses in OA-induced pain. Macrophage migration inhibitory factor (MIF) is a well known pro-inflammatory cytokine. We aimed to determine whether MIF levels in serum and synovial fluid (SF) are associated with severity of OA-induced pain. MATERIAL AND METHODS We recruited 226 patients with knee OA and 106 controls. Self-reported pain severity of OA patients was evaluated using the Western Ontario McMaster University Osteoarthritis (WOMAC) pain scores. MIF levels were detected using enzyme-linked immunosorbent assay (ELISA). RESULTS OA patients had similar serum MIF levels compared to controls (11.93 [5.68-18.10] vs. 10.06 [6.60-14.61] ng/ml, P>0.05). In OA patients, MIF levels in SF were dramatically lower compared to paired serum samples (3.39 [1.87-5.89] vs. 11.93 [5.68-18.10] ng/ml, P<0.01). MIF levels in SF were significantly correlated with WOMAC pain scores (r=0.237, P<0.001), but MIF levels in serum had no significant correlation with WOMAC pain scores (r=0.009, P=0.898). CONCLUSIONS MIF levels in SF, but not in serum, were independently associated with the severity of self-reported pain in OA patients. The inhibition of MIF signaling pathways may be a novel therapeutic approach for ameliorating OA-induced pain.
authors.affiliation: Department of Orthopedic Trauma, Weifang People's Hospital, Weifang, Shandong, China (mainland).
authors.forename: Pei-Liang
authors.initials: PL
authors.lastname: Zhang
authors.affiliation: Department of Orthopedic Trauma, Weifang People's Hospital, Weifang, Shandong, China (mainland).
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Orthopedic Trauma, Weifang People's Hospital, Weifang, Shandong, China (mainland).
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Vascular Surgery, Weifang People's Hospital, Weifang, Shandong, China (mainland).
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Orthopedic Trauma, Weifang People's Hospital, Weifang, Shandong, China (mainland).
authors.forename: Xue-Cheng
authors.initials: XC
authors.lastname: Sun
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000097:blood / Q000378:metabolism*; D008263:Macrophage Migration-Inhibitory Factors / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood / Q000378:metabolism*; D010146:Pain / Q000097:blood / Q000209:etiology / Q000378:metabolism*; D057566:Self Report; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D008263:Macrophage Migration-Inhibitory Factors; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human