Synovial Fluid Of Osteoarthritis Patients Research Articles

Expression profile of cytokines and chemokines in osteoarthritis patients: Proinflammatory roles for CXCL8 and CXCL11 to chondrocytes

There are interactions between immune response and destruction of articular cartilage/synovial tissue in osteoarthritis (OA), which leads to chronic inflammation and systemic failure of joints. However, the role of immunological factors in the pathogenesis of OA has not been fully elucidated. In this study, expressions of 47 cytokines and chemokines were tested in the peripheral bloods and synovial fluids from 13 normal controls (NCs) and 31 OA patients. The primary chondrocytes, which were isolated from cartilages of OA patients, were stimulated by recombinant CXCL8 and CXCL11 to analyze the proliferation, cytokine secretion, and signaling pathways. The levels of IL-17A, CXCL8, CXCL9, and CXCL11 were elevated in the serum and synovial fluids of OA patients. Moreover, expressions of CXCL8 and CXCL11 were remarkably increased in the synovial fluids of late stage OA. Stimulation of CXCL8/11 resulted in the reduction of primary chondrocytes proliferation with downregulation of G2-M stage but elevation of S stage and apoptosis cells. The secretions of proinflammatory cytokines and MMPs were also increased upon stimulation. Furthermore, CXCL8/11 stimulation induced the higher expressions of phosphorylated STAT3, NF-kB p50 and JNK, but not p38MAPK or ERK1/2. Our findings suggested that CXCL8 and CXCL11 promoted the apoptosis and suppressed the proliferation of chondrocytes probably via influencing JAK-STAT, NF-kB and JNK MAPK signaling pathway and enhancing the expressions of other proinflammatory cytokines. CXCL8/11 may aggravate the disease progression of OA, and may also be served as new therapeutic targets for treatment of OA.

Unique gene expression profile in osteoarthritis synovium compared with cartilage: analysis of publicly accessible microarray datasets.

The purpose of this study was to identify a gene expression signature in osteoarthritis (OA) synovium and genomic pathways likely to be involved in the pathogenesis of OA. Four publicly accessible microarray studies from synovium of OA patients were integrated, and a transcriptomic and network-based meta-analysis was performed. Based on pathways according to the Kyoto Encyclopedia of Genes and Genomes, functional enrichment analysis was performed. Meta-analysis results of OA synovium were compared to two previously published studies of OA cartilage to determine the relative number of common and specific DEGs of the cartilage and synovium. According to our meta-analysis, a total of 1350 genes were found to be differentially expressed in the synovium of OA patients as compared to that of healthy controls. Pathway analysis found 41 significant pathways in the total DEGs, and 22 and 16 pathways in the upregulated and downregulated DEGs, respectively. Cell adhesion molecules and cytokine-cytokine receptor interaction were the most significant pathway in the upregulated and downregulated DEGs, respectively. Comparison of meta-analysis results of OA synovium with results of two previous studies of OA cartilage identified 85 common genes and 1632 cartilage-specific DEGs and 1265 synovium-specific DEGs in the first study; and 142 common genes, and 856 cartilage-specific DEGs and 1208 synovium-specific DEGs in the second study. Our results show a small overlap between the DEGs of the synovium compared to DEGs of the cartilage, suggesting different pathogenic mechanisms that are specific to the synovium.

Modulation of Synovial Fluid-Derived Mesenchymal Stem Cells by Intra-Articular and Intraosseous Platelet Rich Plasma Administration.

The aim of this study was to evaluate the effect of intra-articular (IA) or a combination of intra-articular and intraosseous (IO) infiltration of Platelet Rich Plasma (PRP) on the cellular content of synovial fluid (SF) of osteoarthritic patients. Thirty-one patients received a single infiltration of PRP either in the IA space (n = 14) or in the IA space together with two IO infiltrations, one in the medial femoral condyle and one in the tibial plateau (n = 17). SF was collected before and after one week of the infiltration. The presence in the SF of mesenchymal stem cells (MSCs), monocytes, and lymphocytes was determined and quantified by flow cytometry. The number and identity of the MSCs were further confirmed by colony-forming and differentiation assays. PRP infiltration into the subchondral bone (SB) and the IA space induced a reduction in the population of MSCs in the SF. This reduction in MSCs was further confirmed by colony-forming (CFU-F) assay. On the contrary, IA infiltration alone did not cause variations in any of the cellular populations by flow cytometry or CFU-F assay. The SF of osteoarthritic patients contains a population of MSCs that can be modulated by PRP infiltration of the SB compartment.

Biologic basis of osteoarthritis: state of the evidence.

Evidence accumulated since 2010 indicates that human osteoarthritis should now be reclassified as a systemic musculoskeletal disease rather than a focal disorder of synovial joints. Inflammation was seen as the key component promoting synovitis as well as progression of cartilage and bone destruction in osteoarthritis. Thus, metabolic-triggered inflammation involving cytokines, adipokines, abnormal metabolites, acute phase reactants and even complement, all appear to play major roles in osteoarthritis pathophysiology. Immune-mediated inflammation involving T cells and B cells as well as macrophages is now considered a common finding in osteoarthritis synovial tissue. Many experimental and clinical analyses showed that the proinflammatory cytokines, which stimulate matrix metalloproteinase and a disintegrin and metalloproteinase with thrombospondin motif gene transcription in normal and osteoarthritis human chondrocyte cultures, are also present at significantly elevated levels in the synovial fluid of osteoarthritis patients compared with nonarthritic synovial fluids. Human osteoarthritis is a systemic musculoskeletal disorder involving activation of innate and adaptive immune systems accompanied by inflammation exemplified by the elevated production of proinflammatory cytokines, which play a significant role in the progression of the disease. The future of novel therapies for osteoarthritis should consider developing drug development strategies designed to inhibit proinflammatory cytokine-induced signal transduction. These strategies have been successful in the development of drugs for the treatment of rheumatoid arthritis.

Identification of Synovial Fluid Biomarkers for Knee Osteoarthritis and Correlation with Radiographic Assessment.

Osteoarthritis (OA) is a costly and debilitating condition that is typically not diagnosed early enough to prevent progression of disease. The purpose of this study was to evaluate synovial fluid from knees with and without OA for potential markers of joint inflammation and degradation and to correlate these findings with radiographic severity of disease. With Institutional Review Board approval, synovial fluid samples were collected before the patient undergoing total knee arthroplasty. Control knees (n = 3) were patients younger than 30 years of age with no history of anterior cruciate ligament, posterior cruciate ligament, or meniscal injury, and no surgical history for either knee. Weight-bearing, anterior-posterior radiographic views were used to determine radiographic OA severity using the modified Kellgren and Lawrence scale. Synovial fluid samples from 18 patients (21 knees) were analyzed using a multiplex assay. Matrix metalloproteinase (MMP)-1 (p < 0.001), interleukin (IL)-6 (p < 0.013), IL-8 (p < 0.024), and Chemokine (C-C motif) ligand 5 (CCL5) (p < 0.006) were significantly higher in the synovial fluid of OA patients compared with normal patients. The radiographic score was significantly higher in patients with OA compared with normal knees (p < 0.002). MMP-1 had a moderate positive correlation with MMP-2, IL-6, IL-8, and CCL5. IL-6 had a strong positive correlation with IL-8 and a moderate positive correlation with MMP-2. Monocyte chemotactic protein 1 had a moderate positive correlation with IL-6 and a strong positive correlation with IL-8. Radiographic scores had a strong positive correlation with IL-6 and IL-8 and a moderate positive correlation with MCP-1. These data provide novel and clinically relevant information for the investigation of synovial fluid biomarkers for knee OA.

Apolipoprotein-A1 as a damage-associated molecular patterns protein in osteoarthritis: ex vivo and in vitro pro-inflammatory properties.

Osteoarthritis (OA) is associated with a local inflammatory process. Dyslipidemia is known to be an underlying cause for the development of OA. Therefore, lipid and inflammatory levels were quantified ex vivo in blood and synovial fluid of OA patients (n=29) and compared to those of rheumatoid arthritis (RA) patients (n=27) or healthy volunteers (HV) (n=35). The role of apolipoprotein A-I (ApoA1) was investigated in vitro on inflammatory parameters using human joint cells isolated from cartilage and synovial membrane obtained from OA patients after joint replacement. Cells were stimulated with ApoA1 in the presence or not of serum amyloid A (SAA) protein and/or lipoproteins (LDL and HDL) at physiological concentration observed in OA synovial fluid. In our ex vivo study, ApoA1, LDL-C and total cholesterol levels were strongly correlated to each other inside the OA joint cavity whereas same levels were not or weakly correlated to their corresponding serum levels. In OA synovial fluid, ApoA1 was not as strongly correlated to HDL as observed in OA serum or in RA synovial fluid, suggesting a dissociative level between ApoA1 and HDL in OA synovial fluid. In vitro, ApoA1 induced IL-6, MMP-1 and MMP-3 expression by primary chondrocytes and fibroblast-like synoviocytes through TLR4 receptor. HDL and LDL attenuated joint inflammatory response induced by ApoA1 and SAA in a ratio dependent manner. In conclusion, a dysregulated lipidic profile in the synovial fluid of OA patients was observed and was correlated with inflammatory parameters in the OA joint cavity. Pro-inflammatory properties of ApoA1 were confirmed in vitro.

Quantitative proteomic profiling of human articular cartilage degradation in osteoarthritis.

Osteoarthritis (OA) is the most common rheumatic pathology and is characterized primarily by articular cartilage degradation. Despite its high prevalence, there is no effective therapy to slow disease progression or regenerate the damaged tissue. Therefore, new diagnostic and monitoring tests for OA are urgently needed, which would also promote the development of alternative therapeutic strategies. In the present study, we have performed an iTRAQ-based quantitative proteomic analysis of secretomes from healthy human articular cartilage explants, comparing their protein profile to those from unwounded (early disease) and wounded (advanced disease) zones of osteoarthritic tissue. This strategy allowed us to identify a panel of 76 proteins that are distinctively released by the diseased tissue. Clustering analysis allowed the classification of proteins according to their different profile of release from cartilage. Among these proteins, the altered release of osteoprotegerin (decreased in OA) and periostin (increased in OA), both involved in bone remodelling processes, was verified in further analyses. Moreover, periostin was also increased in the synovial fluid of OA patients. Altogether, the present work provides a novel insight into the mechanisms of human cartilage degradation and a number of new cartilage-characteristic proteins with possible biomarker value for early diagnosis and prognosis of OA.

AB1005 Glycosaminoglycan in Synovial Fluid of Osteoarthritis Patients Validates Kellgren-Lawrence Score as a Useful Indicator for Disease Progression and Cartilage Degradation

BackgroundCartilage is a marvel design, which handles a remarkable pressure in weight bearing joints yet facilitates resilient movement. Osteoarthritis (OA) is a disease characterised by progressive degeneration of cartilage, which...

OP0219 T Cells in the Infrapatellar FAT PAD of Osteoarthritis Patients as A Source of IL-6 in the Joint

BackgroundObesity is associated with the development and progression of osteoarthritis (OA) and it is believed that obesity-associated adipose tissue inflammation could play a role in this association. The infrapatellar fat...

Soluble TNF receptors are produced at sites of inflammation and are inversely associated with self-reported symptoms (WOMAC) in knee osteoarthritis.

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.

Granulocyte-macrophage colony stimulating factor and its receptor CD116 expression in the synovium of osteoarthritis patients is negatively correlated with pain

Granulocyte-macrophage colony stimulating factor and its receptor CD116 expression in the synovium of osteoarthritis patients is negatively correlated with pain

Urotensin II (U-II), a novel cyclic peptide, possibly associated with the pathophysiology of osteoarthritis

Synovial fibrosis is one of the main outcomes of osteoarthritis. Some authors have reported that urotensin-II (U-II) may cause pathologic fibrosis in cardiovascular system, lung and liver. However there are no previous reports available in the literature about its relationship with the synovial fibrosis in osteoarthritis. The aim of this study was to compare the U-II levels in knee synovial fluids obtained from osteoarthritic and non-osteoarthritic patients. Two groups were created, the osteoarthritis group and non-osteoarthritic control group. The control group was consisted of patients who underwent arthroscopic surgery for other reasons than cartilage disorders. In the osteoarthritis group all patients had grade 4 primer degenerative osteoarthritis and were treated with total knee arthroplasty. Minimum 1mL knee synovial fluids were obtained during operation. Levels of U-II were measured by using ELISA kit U-II levels were significantly higher in the osteoarthritic group than that in the control group. No correlation was found between U-II levels and age. In conclusion, the significantly high U-II levels in the knee synovial fluid of osteoarthritic patients supported our hypothesis that “U-II may be associated with the synovial fibrosis in osteoarthritis”.

Involvement of BDNF in knee osteoarthritis: the relationship with inflammation and clinical parameters

The aim of this study was to analyze the levels of brain-derived neurotrophic factor (BDNF) in both the plasma and synovial fluid of patients with primary knee osteoarthritis compared with control individuals and to investigate the relationship between BDNF levels and self-reported pain. Twenty-seven patients with knee osteoarthritis (OA) and 19 healthy subjects were enrolled in the study. Anteroposterior knee radiographs were taken to determine the disease severity of the affected knee. Radiographic grading of OA in the knee was performed using the Kellgren-Lawrence criteria. The BDNF levels in the plasma and synovial fluid were measured by enzyme-linked immunosorbent assay. The mean plasma BDNF levels of the knee OA patients were significantly higher than that of the healthy controls (2,378 ± 1,067.2 vs. 1,756 ± 804.3 pg/mL, p < 0.05). BDNF levels in the synovial fluid of OA patients (358.9 ± 178.4 pg/mL) were sixfold lower than in corresponding blood samples (p < 0.0001) and fourfold lower than in the plasma of healthy controls (p < 0.0001). Subsequent analyses showed that the plasma BDNF levels significantly correlated with self-reported pain (Western Ontario and McMaster Universities Osteoarthritis Index) (r s = 0.39, p = 0.04). Furthermore, no correlation was found between the plasma and synovial fluid BDNF concentrations and knee OA severity. The findings of this study suggest that systemic BDNF levels are most likely associated with the mechanism of joint pain in knee OA in the acute stage of joint inflammatory process. Further studies are necessary to address the functional role of BDNF in the modulation of pain to establish new therapeutic implications.

Differential proteomic analysis of synovial fluid from rheumatoid arthritis and osteoarthritis patients

BackgroundRheumatoid arthritis and osteoarthritis are two common musculoskeletal disorders that affect the joints. Despite high prevalence rates, etiological factors involved in these disorders remain largely unknown. Dissecting the molecular aspects of these disorders will significantly contribute to improving their diagnosis and clinical management. In order to identify proteins that are differentially expressed between these two conditions, a quantitative proteomic profiling of synovial fluid obtained from rheumatoid arthritis and osteoarthritis patients was carried out by using iTRAQ labeling followed by high resolution mass spectrometry analysis.ResultsWe have identified 575 proteins out of which 135 proteins were found to be differentially expressed by ≥3-fold in the synovial fluid of rheumatoid arthritis and osteoarthritis patients. Proteins not previously reported to be associated with rheumatoid arthritis including, coronin-1A (CORO1A), fibrinogen like-2 (FGL2), and macrophage capping protein (CAPG) were found to be upregulated in rheumatoid arthritis. Proteins such as CD5 molecule-like protein (CD5L), soluble scavenger receptor cysteine-rich domain-containing protein (SSC5D), and TTK protein kinase (TTK) were found to be upregulated in the synovial fluid of osteoarthritis patients. We confirmed the upregulation of CAPG in rheumatoid arthritis synovial fluid by multiple reaction monitoring assay as well as by Western blot. Pathway analysis of differentially expressed proteins revealed a significant enrichment of genes involved in glycolytic pathway in rheumatoid arthritis.ConclusionsWe report here the largest identification of proteins from the synovial fluid of rheumatoid arthritis and osteoarthritis patients using a quantitative proteomics approach. The novel proteins identified from our study needs to be explored further for their role in the disease pathogenesis of rheumatoid arthritis and osteoarthritis.Sartaj Ahmad and Raja Sekhar Nirujogi contributed equally to this article.

Inhibition of oncostatin M in osteoarthritic synovial fluid enhances GAG production in osteoarthritic cartilage repair

Mediators in the synovial fluid are thought to play a major role in osteoarthritic cartilage turnover. The purpose of the current study was to investigate the role of oncostatin M (OSM) in osteoarthritis (OA) by evaluating the presence of the cytokine and its receptors in the OA joint and interfering with its activity in synovial fluid co-cultured with cartilage explants. OSM levels were increased in the synovial fluid of osteoarthritic patients compared to healthy donors. Immunohistochemistry confirmed the presence of both the leukaemia inhibitory factor (LIF) and OSM receptors for OSM throughout the whole depth of osteoarthritic cartilage and synovial tissue, whereas in healthy cartilage their presence seemed more restricted to the superficial zone. Blocking OSM activity, using an activity inhibiting antibody, in 25% osteoarthritic synovial fluid added to OA cartilage explant cultures increased glycosaminoglycan (GAG) content from 18.6mg/g to 24.3mg/g (P<0.03) and total production from 7.0mg/g to 11.9mg/g (P<0.003). However, OSM exogenously added to cartilage explant cultures reflecting low and high concentrations in the synovial fluid (5 and 50pg/mL) did not affect cartilage matrix turnover, suggesting that factors present in the synovial fluid act in concert with OSM to inhibit GAG production. The current study indicates the potential to enhance cartilage repair in osteoarthritis by modulating the joint environment by interfering with OSM activity.

AB0079 Presence of extracellular rna and rnase in synovial tissue and synovial fluid of patients with rheumatoid arthritis

BackgroundRheumatoid arthritis (RA) is a chronic inflammatory disease characterized by the destruction of cartilage and bone in affected joints. It is known that various pro-inflammatory and pro- destructive factors are...

AB0073 The s100a9 inhibitor paquinimod (abr-215757) ameliorates experimental osteoarthritis with high synovial involvement

BackgroundThere is increasing evidence that synovial activation contributes to osteoarthritis (OA) pathology and that it is present in a large subset of OA patients. Previously, we found that alarmins S100A8...

An oral preparation containing hylauronic acid (Oralvisc®) can normalize the turnover of hyaluronic acid in synovial fluid of osteoarthritic knee patients

An oral preparation containing hylauronic acid (Oralvisc®) can normalize the turnover of hyaluronic acid in synovial fluid of osteoarthritic knee patients

Detection of the expression level of miR-140 using realtime fluorescent quantitative PCR in knee synovial fluid of osteoarthritis patients

To examine the expression of microRNA-140 (miR-140) in osteoarthritis (OA) graded by X-ray diagnosis criteria of Kellgren and Lawrence and to provide a theoretical basis for further studing the role of miR-140 in OA development. Knee synovial fluid specimens were collected in 40 OA patients (the OA group), the OA group was divided into 4 subgroups according to X-ray diagnosis criteria of Kellgren and Lawrence: gradeIsubgroup (n=10), gradeII subgroup (n=10), gradeIII subgroup (n=10), and grade IV subgroup(n=10). Twenty patients served as a control group (the control group), including meniscus injury, cruciate ligament injury, trauma patients. The expression level of miR-140 in the knee synovial fluid was detected by real-time fluorescent quantitative polymerase chain reaction (stem-loop RT-qPCR, TaqMan). U6 snRNA was used as the reference control, and Ct value was calculated. MiR-140 was detected in all knee synovial fluid specimens. The expression level of miR-140 in the OA group was much lower than that in the control groupb (P<0.05). There was significant difference in the expression level of miR-140 between the grade IV subgroup and the gradeI, gradeII and gradeIII subgroups (all P<0.05). The expression levels of miR-140 was negatively related to the severity of OA (r=-0.917, P<0.05). MiR-140 in human knee synovial fluid can be detected conveniently by real-time PCR. The expression level of miR-140 decreases in the knee synovial fluid in OA patients, and is negatively related to the severity of OA. This may be related to the occurrence and development of OA, and can provide early potential diagnostic molecular target.

Extracellular nicotinamide phosphoribosyltransferase (NAMPT/visfatin) inhibits insulin-like growth factor-1 signaling and proteoglycan synthesis in human articular chondrocytes

IntroductionObesity is one of the major risk factors for the development of osteoarthritis (OA). Although the mechanical factors appear to be critical, recent studies have suggested a role for adipokines in cartilage degradation. Chondrocytes from osteoarthritic cartilage respond poorly to insulin-like growth factor-1 (IGF-1) and the molecular mechanism(s) involved is not clearly understood. The purpose of the present study was to determine the role of extracellular nicotinamide phosphoribosyltransferase (eNAMPT/visfatin), a newly described adipokine, in regulating IGF-1 function in chondrocytes.MethodsHuman articular chondrocytes isolated from normal ankle cartilage were pretreated with eNAMPT (0.1 to 5.0 μg/ml) overnight followed by stimulation with IGF-1 (50 ng/ml) for 24 hours, and proteoglycan synthesis was measured by [35S]sulfate incorporation. Chondrocytes were pretreated with eNAMPT overnight followed by IGF-1 for 10 minutes, and the cell lysates were immunoblotted for various signaling proteins that are activated by IGF-1 using phosphospecific antibodies. In addition, chondrocytes were pretreated with mitogen-activated protein kinase kinase inhibitor (U0126) prior to stimulation with eNAMPT and IGF-1.ResultsPretreatment of chondrocytes with eNAMPT inhibited IGF-1-stimulated proteoglycan synthesis in a dose-dependent manner. Treatment of chondrocytes with eNAMPT inhibited IGF-1-induced phosphorylation of signaling molecules, including insulin receptor substrate-1 and AKT. Interestingly, pretreatment of chondrocytes with eNAMPT did not inhibit IGF-1-mediated phosphorylation of the IGF-1 receptor; however, it stimulated a sustained phosphorylation of the extracellular signal-regulated kinase (ERK)/mitogen activated protein kinase (MAPK) signaling pathway. Inhibition of the ERK/MAPK signaling pathway restored IGF-1-mediated insulin receptor substrate-1 and AKT phosphorylation.ConclusionsOur study demonstrates that eNAMPT/visfatin inhibits IGF-1 function in articular chondrocytes by activating the ERK/MAPK pathway independent of the IGF-1 receptor. Since eNAMPT levels are elevated in the synovial fluid of OA patients, the signaling pathway activated by eNAMPT could contribute to IGF-1 resistance in OA.