title: Soluble TNF receptors are produced at sites of inflammation and are inversely associated with self-reported symptoms (WOMAC) in knee osteoarthritis.
abstract: The aim of the study was to analyze the concentrations of sTNFR1 and sTNFR2 in both plasma and synovial fluid of patients with primary knee osteoarthritis (OA) and to determine their relationship to self-reported pain, stiffness and physical function. Twenty-seven patients with knee OA and 19 healthy subjects were enrolled in the study. The Western Ontario and McMaster University Osteoarthritis Index questionnaire was used to evaluate self-reported physical function, pain and stiffness. The sTNFR1 and sTNFR2 levels in the plasma and synovial fluid were measured by enzyme-linked immunosorbent assay. The sTNFR1 levels in synovial fluid of OA patients (2,587 ± 66.12 pg/mL) were 2.5-fold higher than in corresponding blood samples and were 1.5-fold higher than in the plasma of healthy controls. The plasma sTNFR2 levels in the patients with knee OA were lower than in healthy controls (2,249 ± 126.3 vs. 2,700 ± 126.3 pg/mL, p < 0.05), and sTNFR2 levels in synovial fluid of knee OA patients (2,021 ± 107.0 pg/mL) were lower than in the plasma of healthy controls. Synovial fluid sTNFR1 levels were negatively correlated with pain and physical function self-reported (r s - 0.6785, p < 0.0001 and r s - 0.4194, p = 0.03, respectively). Synovial fluid sTNFR2 levels were negatively correlated with pain and joint stiffness (r s - 0.5433, p = 0.01 and r s - 0.4249, p = 0.02, respectively). The findings of this study demonstrated the presence of soluble receptors for TNF-alpha, particularly sTNFR1, in the synovial fluid of patients with primary knee OA and the relationship of these receptors with clinical parameters.
authors.affiliation: Integrated Center for Graduate Studies and Research Health (CIPq-Health), Federal University of the Jequitinhonha and Mucuri Valleys (UFVJM), Diamantina, Minas Gerais, Brazil, adrianopsimao@ig.com.br.
authors.forename: Adriano Prado
authors.initials: AP
authors.lastname: Simão
authors.forename: Tássio Málber de Oliveira
authors.initials: TM
authors.lastname: Almeida
authors.forename: Vanessa Amaral
authors.initials: VA
authors.lastname: Mendonça
authors.forename: Sérgio Antunes
authors.initials: SA
authors.lastname: Santos
authors.forename: Wellington Fabiano
authors.initials: WF
authors.lastname: Gomes
authors.forename: Cândido Celso
authors.initials: CC
authors.lastname: Coimbra
authors.forename: Ana Cristina Rodrigues
authors.initials: AC
authors.lastname: Lacerda
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D010147:Pain Measurement; D011237:Predictive Value of Tests; D011379:Prognosis; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000097:blood*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000097:blood*; D057566:Self Report; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000276:immunology*
chemical_list: D015415:Biomarkers; D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; C506235:TNFRSF1A protein, human; C415902:TNFRSF1B protein, human
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