Synovial Fluid Biomarkers Research Articles

Higher aggrecan 1-F21 epitope concentrations in synovial fluid early after knee injury are associated with worse cartilage quality 20 years later

Purpose: To investigate if synovial fluid biomarkers of cartilage turnover acutely or years after an anterior cruciate ligament (ACL) injury are associated with subsequent knee cartilage status 20 years after injury. Methods: We studied a cohort of 32 patients who had coped with an ACL injury without ACL reconstruction and presented without radiographic diagnosis of osteoarthritis 16 years post injury. All had a delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) 20 years after a complete ACL tear. 25 out of 32 had one or more available synovial fluid samples aspirated without lavage either acutely after injury, or during 1-5 (median 4) follow up visits between 0.6 and 7 years after injury, and were included in this study (Table 1).Tabled 1Table 1 Characteristic of the 25 study subjects grouped by synovial fluid (SF) availability.Acute SF sampleChronic SF sample *n (% males)19 (63)22 (50)Age at injury, mean years (SD)25.2 (6.5)24.7 (6.3)BMI 20 years post-injury, mean (SD)25.3 (4.0)25.6 (3.6)Time between injury and sampling, median (range)4 (<1 to 13) days3.1 (0.6 to 7.1) yearsYears between injury and dGEMRIC, median (range)20.2 (18.8 to 23.1)20.2 (18.4 to 23.1)* 1-5 per individual, using the mean biomarker concentration or time for each individual. Open table in a new tab We quantified synovial fluid concentrations of two aggrecan epitopes (the 1-F21 epitope residing in or close to the keratan sulfate rich region, and the ARGS neoepitope generated by aggrecanase cleavage in the interglobular domain), cartilage oligomeric matrix protein (COMP), matrix metalloproteinase-3 (MMP-3) and tissue inhibitor of metalloproteinase-1 (TIMP-1) by immunoassays, and sulfated glycosaminoglycan (sGAG) content by Alcian blue precipitation. We created the ratio MMP-3/TIMP-1 to investigate differences in using these biomarkers alone or as a ratio between the enzyme and its inhibitor. We also investigated the ratios aggrecan/COMP, since the ratio 1-F21 aggrecan/COMP was reported to be more elevated in subjects with more progressive cartilage destruction in rheumatoid arthritis than 1-F21 aggrecan alone. Linear regression analysis was used to investigate associations between acute or chronic biomarker concentrations and cartilage quality at 20 years post injury. We included adjustments for age, sex, BMI at 20 years, and time between injury and knee puncture. For subjects with more than one chronic visit, we used the mean values for biomarkers and time in the regression models. Biomarker concentrations were log 10 transformed to achieve linear relationships with dGEMRIC values. To be able to compare effect sizes between biomarkers, we report standardized effects from the linear regression analysis. Results: With negative standardized effects close to 1, higher synovial fluid 1-F21 aggrecan concentrations or higher ratio 1-F21 aggrecan to COMP early after ACL injury were associated with shorter T1Gd values (inferior cartilage quality) 20 years later (Figure 1A). There was no similar association between acute ARGS aggrecan or sGAG content and T1Gd (Figure 1A), nor was chronic 1-F21 aggrecan concentrations associated with T1Gd values (Figure 1B). High similarity in the standardized effect sizes between aggrecan or sGAG concentrations alone and as ratios with COMP (Figures 1A and 1B), indicate that there was no added value in making such ratios compared to using the biomarker concentrations alone. Neither MMP-3 concentrations, nor the ratio MMP-3/TIMP-1 were predictive of subsequent cartilage quality in these subjects, which is consistent with previous findings of no apparent role of MMP-3 in pathological turnover of aggrecan. Conclusions: Acute (but not chronic) turnover of aggrecan generating increased synovial fluid concentrations of the 1-F21 epitope of aggrecan was associated with worse cartilage quality assessed by dGEMRIC 20 years later. Measuring specific aggrecan fragments carrying different epitopes appears to be important when investigating aggrecan as a predictive biomarker of cartilage quality.

Post traumatic osteoarthritis: baseline synovial fluid biomarkers are associated with cartilage biochemistry measured using MRI one year after ACL reconstruction

Post traumatic osteoarthritis: baseline synovial fluid biomarkers are associated with cartilage biochemistry measured using MRI one year after ACL reconstruction

Alterations in Synovial Fluid Biomarker Levels in Knees With Meniscal Injury as Compared With Asymptomatic Contralateral Knees

Background: Changes in the joint microenvironment after an injury to the articular surface of the knee have been implicated in the pathogenesis of osteoarthritis. While prior studies focused on changes in this microenvironment after anterior cruciate ligament ruptures, few have explored the biomarker changes that occur in the setting of meniscal injuries. Purpose: To determine whether meniscal injury results in significant alterations to synovial fluid biomarker concentrations as compared with noninjured contralateral knees. Additionally, to explore the relationship between synovial fluid biomarkers and the degree of cartilage injury seen in these patients. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Patients undergoing surgery for unilateral meniscal injury were prospectively enrolled from October 2011 to December 2016, forming a cohort that had synovial fluid samples collected from both the injured knee and the contralateral uninjured knee at the time of meniscal surgery. Synovial fluid samples were collected just before incision, and the concentrations of 10 biomarkers of interest were determined with a multiplex magnetic bead immunoassay. The concentrations of synovial fluid biomarkers from the operative and contralateral knees were compared. Additionally, the synovial fluid biomarker concentrations of operative knees from patients with associated high-grade cartilage lesions were compared with those with low-grade lesions. Results: The current analysis included synovial fluid samples from 82 knees (41 operative and 41 contralateral) from 41 patients undergoing arthroscopic surgery to treat a symptomatic meniscal injury. The mean ± SD age of patients was 49.86 ± 11.75 years. There were significantly greater concentrations of 4 of the 5 proinflammatory biomarkers (IL-6, MCP-1, MIP-1β, and MMP-3) in symptomatic knees as compared with asymptomatic knees when controlling for the duration of symptoms, body mass index, age, and the random effects of by-patient variability. In the injured knees, associated high-grade cartilage lesions were predictive of elevated MCP-1, MIP-1β, and VEGF levels. Low synovial fluid concentration of TIMP-1 or a greater ratio of MMP-3 to TIMP-1 was associated with the presence of synovitis. Increasing age was found to be an independent predictor of increased IL-6, MCP-1, and VEGF concentrations in the setting of symptomatic meniscal injury. Conclusion: The authors identified 4 proinflammatory synovial fluid biomarkers whose concentrations were significantly different after meniscal injury as compared with uninjured contralateral knees. Furthermore, they describe the effects of associated cartilage damage, synovitis, and patient age on biomarker concentrations.

Suppression of cathepsin K biomarker in synovial fluid as a free-drug–driven process

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Suppression of cathepsin K biomarker in synovial fluid as a free-drug-driven process.

Cathepsin K (CatK) inhibitors exhibited chondroprotective and pain-reducing effects in animal models, however, improvements were relatively modest at dose levels achieving maximal suppression of CatK biomarkers in urine. In this report, a previously characterized CatK inhibitor (MK-1256) is utilized to explore the potential of reduced target engagement and/or suboptimal exposure (free drug) as limiting factors to the pharmacological potential of CatK inhibitors in the knee joint. Following oral administration of MK-1256 at a dose level achieving maximal inhibition of urinary biomarker (helical peptide) in dogs, full suppression of the biomarker in synovial fluid was observed. Subsequent tissue distribution studies conducted in dogs and rabbits revealed that MK-1256 levels in synovial fluid and cartilage were consistent with the free-drug hypothesis. Reasonable projection (within twofold) of drug levels in these tissues can be made based on plasma drug concentration with adjustments for binding factors. These results indicate that the previously observed efficacies in the animal models were not limited by compound distribution or target engagement in the knee tissues.

Oral glucosamine and chondroitin sulfate on synovial fluid biomarkers from osteoarthritic equine joints

ABSTRACT: Several studies, mainly in vitro, have shown that chondroitin sulfate (CS) and glucosamine (GlcN) do have chondro protective and anti-inflammatory actions. The aim of the present study was to investigate whether oral CS/GlcN supplementation has effects on the CS, hyaluronic acid (HA) and prostaglandin E2 (PGE2) concentrations on synovial fluid of equine osteoarthritic joints. Horses with mild osteoarthritis (OA) in tibiotarsal joint received daily PO doses of CS and GlcN (2.8/3.1 g) for 25 days. Synovial fluid (SF) and urine samples were collected before treatment (day 0), and every 7 days, until day 55 (30 days after the end of treatment). Urinary CS increased upon oral treatment, indicating that this compound was systemically distributed. Concerning the SF, CS concentration increased after the end of the treatment and returning to baseline afterwards, while HA and PGE2 concentrations did not change. Despite the systemic distribution, oral supplementation of CS/GlcNfor 25 days was insufficient as an anti-inflammatory support. However, it is possible to infer that there was an anabolic effect upon cartilage matrix.

The role of alpha defensin in prosthetic joint infection (PJI) diagnosis: a literature review.

Prosthetic joint infection (PJI) management is not standardized worldwide and the outcome is frequently unsatisfactory.More and more arthroplasties are now being performed. An increasing number of highly virulent and antibiotic-resistant bacteria and an ageing population of patients presenting with many comorbidities make it necessary to focus on this important topic.Diagnosis of PJI remains challenging because the clinical signs and symptoms and elevation of systemic biomarkers (C-reactive protein, erythrocyte sedimentation rate) may be unclear.In the last few years, the clinical research has focused on synovial fluid biomarkers as a possible breakthrough in the complex scenario of PJI diagnosis.Synovial biomarkers have shown encouraging results and they should be used as diagnostic adjuncts to synovial white cell count and culture bacteriology. Synovial leukocyte esterase (LE) and synovial C-reactive protein (CRP) have been evaluated as good screening measures; however, the most promising synovial fluid biomarker in terms of sensitivity and specificity for PJI seems to be alpha defensin (AD).The laboratory-based alpha defensin enzyme-linked immunosorbent assay (ELISA) test demonstrated the highest ever reported accuracy for PJI diagnosis. However, an alpha defensin lateral flow test could have its place in ruling in a suspected PJI intraoperatively because of its high specificity and rapid results.Cite this article: EFORT Open Rev 2019;4:10-13. DOI: 10.1302/2058-5241.4.180029

Molecular and Structural Biomarkers of Inflammation at Two Years After Acute Anterior Cruciate Ligament Injury Do Not Predict Structural Knee Osteoarthritis at Five Years.

To determine the role of inflammatory biomarkers at 2 years post-anterior cruciate ligament (ACL) injury to predict radiographic knee osteoarthritis (OA) and magnetic resonance imaging (MRI)-defined knee OA at 5 years postinjury, with a secondary aim of estimating the concordance of inflammatory biomarkers assessed by MRI and synovial fluid (SF) analysis. We studied 113 patients with acute ACL injury. Knee scans using 1.5T MRIs were read for Hoffa- and effusion-synovitis. Biomarkers of inflammation that we assessed included interleukin-6 (IL-6), IL-8, IL-10, tumor necrosis factor, and interferon-ɣ in serum and SF, and IL-12p70 in serum. We defined the outcome as radiographic knee OA (ROA) or MRI-defined OA (MROA) at 5 years. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were evaluated in models that included MRI features only (model 1), inflammation biomarkers only (serum [model 2a] or SF [model 2b]), both MRI features and serum biomarkers (model 3a), or both MRI features and SF (model 3b) biomarkers. Linear regression analysis was used to evaluate the association between MRI features and SF biomarkers. At 5 years postinjury, ROA was present in 26% of the injured knees, and MROA was present in 32%. The AUCs for ROA in each model were 0.44 (95% confidence interval [95% CI] 0.42, 0.47) for model 1, 0.62 (95% CI 0.59, 0.65) for model 2a, 0.53 (95% CI 0.50, 0.56) for model 2b, 0.58 (95% CI 0.55, 0.61) for model 3a, and 0.50 (95% CI 0.46, 0.53) for model 3b. The AUCs for MROA in each model were 0.67 (95% CI 0.64, 0.70) for model 1, 0.49 (95% CI 0.47, 0.52) for model 2a, 0.56 (95% CI 0.52, 0.59) for model 2b, 0.65 (95% CI 0.61, 0.68) for model 3a, and 0.69 (95% CI 0.66, 0.72) for model 3b. The concordance between MRI and SF biomarkers was statistically significant only for effusion-synovitis and IL-8. Neither MRI-detected inflammation nor selected SF/serum inflammation biomarkers at 2 years postinjury predicted ROA or MROA at 5 years postinjury. Concordance between MRI and SF inflammatory biomarkers was weak.

Anti-arthritic effect of pentosan polysulfate in rats with collagen-induced arthritis

Pentosan polysulfate (PPS) is currently under investigation as a potential disease-modifying antiarthritic agent. In the present study the effects of PPS on arthritic profiles based on clinical score, ankle size, histological changes, and activity of inflammatory mediators using collagen-induced arthritic rat are reported. Model of arthritis was developed in Sprague Dawley rats by intradermal injection of bovine type II collagen emulsified with incomplete Freund's adjuvant. The rats were randomly divided into four groups: normal control, arthritic control, arthritic rats treated with PPS (at dose level 20 μg/g) and arthritic rats treated with meloxicam (2 μg/g). The treatment was continued daily until the day 30. Arthritic biomarkers (cartilage oligomeric matrix protein and tartrate-resistant acid phosphatase 5b) in synovial fluid, expression of inflammatory mediators (interleukin-1β, and tumor necrosis factor-α) and osteoclast marker genes (cathepsin K, tartrate-resistant acid phosphatase) in synovial membrane were measured. Daily administration of PPS to the arthritic rats significantly decreased the severity of arthritis by effectively suppressing the symptoms of arthritis and improving the functional recovery based on clinical score and histopathological evidence. Intriguingly, identical downregulation pattern of arthritis profiles, biological markers as well as relative mRNA levels of osteoclast markers and cytokines were monitored in arthritic rats treated with PPS. In conclusion, PPS exerted protective effects against collagen-induced arthritis in rats. The results suggest that PPS acts as an anti-inflammatory and anti-arthritic agent in decreasing the arthritic effects in collagen-induced arthritic rats.

Current Recommendations for the Diagnosis of Acute and Chronic PJI for Hip and Knee-Cell Counts, Alpha-Defensin, Leukocyte Esterase, Next-generation Sequencing.

Despite significant progress in recent years, the diagnosis of periprosthetic joint infection (PJI) remains a challenge and no gold standard test exists. A combination of serological, synovial, microbiological, histological, and radiological investigations is performed that are expensive, often invasive, and imperfect. Novel biomarkers and molecular methods have shown promise in recent years. The purpose of this review is to provide an update about the diagnostic recommendations for PJI and cover a selection of emerging diagnostic tools. Recent literature highlights a new evidence-based definition for diagnosing hip and knee PJI that shows excellent performance on formal external multi-institutional validation. There is also increasing evidence to support the measurement of selected biomarkers in serum and synovial fluid, such as alpha-defensin, D-dimer, and interleukin-6. Finally, the emerging utility of next-generation sequencing for pathogen identification is discussed. In summary, we describe current recommendations and emerging tests for the diagnosis of PJI. Residual limitations and directions for future research are also discussed.

Is the Enzyme-linked Immunosorbent Assay More Accurate Than the Lateral Flow Alpha Defensin Test for Diagnosing Periprosthetic Joint Infection?

Alpha defensin was proposed as a new biomarker in synovial fluid for the diagnostic workup of failed joint prostheses. To our knowledge, no comparative study of the performance of the quantitative enzyme-linked immunosorbent assay (ELISA) and qualitative lateral flow alpha defensin test has been reported. (1) Using the proposed European Bone and Joint Infection Society (EBJIS) criteria for defining periprosthetic joint infection (PJI), is there a difference in the diagnostic accuracy of quantitative ELISA and qualitative lateral flow alpha defensin tests? (2) Is there a difference in the performance of the two alpha defensin tests when using three definition classification systems (Musculoskeletal Infection Society [MSIS], Infectious Diseases Society of America [IDSA], and proposed EBJIS)? In this retrospective study of samples collected earlier as part of a related longitudinal study, we included patients in whom aspiration of the prosthetic hip or knee was performed as routine investigation before every revision arthroplasty. Between October 2016 and April 2017, a total of 73 patients were eligible for inclusion. As a result of an insufficient fluid volume for analysis (< 5 mL), two patients were excluded. Among the 71 patients in the final analysis, 54 had a knee and 17 a hip arthroplasty. Using the proposed EBJIS criteria, PJI was diagnosed in 22 patients (31%) and aseptic failure in 49 (69%). The alpha defensin ELISA and lateral flow tests were performed in synovial fluid. Patients were classified as having PJI or aseptic failure using the MSIS, the IDSA, and the proposed EBJIS criteria. Sensitivity and specificity of ELISA and the lateral flow alpha defensin test were calculated. Based on receiver operating characteristic analysis, area under the curve values were compared. When measured against the proposed EBJIS criteria, the sensitivity of alpha defensin ELISA and the lateral flow test was low and not different from one another with the numbers available at 50% (95% confidence interval [CI], 31%-69%) and 46% (95% CI, 27%-65%; p = 0.857), respectively, whereas both methods showed high specificity (98% [95% CI, 88%-100%]; p = 1.000). For sensitivity, the highest values were seen when compared against the MSIS criteria (ELISA: 85% [95% CI, 56%-97%], lateral flow: 77% [95% CI]; p = 0.871), intermediate with IDSA criteria (ELISA: 73% [95% CI, 48%-89%], lateral flow: 67% [95% CI]; p = 0.867), and lowest with proposed EBJIS criteria (ELISA: 50% [95% CI, 31%-69%], lateral flow: 46% [95% CI]; p = 0.763). Specificity, however, was high regardless of the criteria used, where ELISA and lateral flow produced results that were not different (MSIS: 98% [95% CI, 90%-100%], IDSA: 98% [95% CI, 90%-100%], EBJIS: 98% [95% CI, 88%-100%]; p = 1.000). The area under the curve of alpha defensin ELISA and the lateral flow test was similar, regardless of the definition criteria used (EBJIS: p = 0.566; IDSA: p = 0.425; MSIS: p = 0.339). There is no difference between the quantitative and qualitative alpha defensin test for confirmation of PJI, irrespective of applied definition criteria. Having the advantage of providing results within 10 minutes without the need for a laboratory facility, the qualitative test may be of interest in the intraoperative setting, however, at a cost of higher test expense. Level I, diagnostic study.

Correlation Between Synovial Fluid Biomarker Concentrations and Bone Marrow Edema Lesion Volume in Patients with Acute ACL Ruptures

Objectives:Bone marrow edema lesions (BMELs) frequently occur following acute anterior cruciate ligament (ACL) rupture secondary to the pivot-shift mechanism of injury. The aim of the current study is to evaluate whether synovial fluid biomarker concentrations are associated with bone edema lesion volume as measured by magnetic resonance imaging (MRI) in patients undergoing ACL reconstruction.Methods:A total of 53 patients (26 females, 27 males, mean age 35.0 years [range 18-59]) undergoing ACL reconstruction with MRI knee scans available for analysis participated in the study. Synovial fluid was collected intra-operatively and analyzed for 10 biomarkers hypothesized to be involved in inflammation and post-traumatic osteoarthritis. BMELs were identified on MRI and their volumes (cm3) were quantified on two independent occasions using FireVoxel imaging software for image segmentation and region-of-interest drawing. The correlation between synovial fluid biomarker levels and BMEL volume was evaluated using Spearman’s correlation coefficient. Measurement reliability was assessed using intraclass correlation coefficient (ICC) analysis. Significance was set at p<0.05.Results:Mean time from initial injury to synovial fluid aspiration was 319 days (std. dev. 892; range 15-4320) and mean lesion volumes were: tibial=6.4 cm3 (range 0-38.6); femoral=5.8 cm3 (range 0-34.0); total=12.2 cm3 (range 0-50.5). Measurement reliability of BMEL volume was excellent [ICC(2,1)=0.968 (CI 0.945-0.981)]. Analysis of patients with MRI within 30 days of injury (n=35) showed increased tibial BMEL volume was significantly (p<0.05) correlated to decreased concentrations of interleukin (IL)-6 (ρ=-0.481), IL-1 receptor antagonist (ρ=-0.361), and vascular endothelial growth factor (VEGF) (ρ=-0.397) and increased time from injury to aspiration was correlated to decreased concentration of IL-6 (ρ=-0.463), monocyte chemotactic protein-1 (ρ=-0.453), VEGF (ρ=-0.457), IL-1Ra (ρ=-0.448), and matrix metalloproteinase (MMP)-3 (ρ=-0.426). However, among all patients, synovial fluid biomarker levels had no significant correlations to BMEL volume or time from injury to aspiration.Conclusion:Analysis of synovial fluid at the time of ACL reconstruction demonstrated that increased volume of injury-associated BMEL on MRI performed within 30 days of initial injury was significantly correlated to decreased concentrations of pro-inflammatory and growth factor cytokines. These findings suggest that the impact of the pivot-shift mechanism of injury and presence of BMEL may have an affect the local joint microenvironment.Table 1.Biomarker Values and Correlation with Bone Edema Lesion Size in Patients with MRI Within 30 Days of Initial InjuryNumber of samplesMean (pg/ml)Standard Deviation (pg/ml)Spearman correlation with lesion sizeTibiaFemoralTotalRANTES35591.071972.12-0.03-0.10-0.11IL-635177.69493.79 -0.48* 0.21-0.19MCP-135366.15213.50-0.310.17-0.12MIP-B3550.9885.41-0.180.12-0.03VEGF35328.79303.13 -0.39* 0.26-0.13TIMP135369909.29156363.48-0.070.10-0.05TIMP23593235.0296963.730.13-0.060.07IL-1Ra35418.071754.43 -0.36* 0.00-0.26MMP3353373710.563763593.71-0.130.310.04bFGF3548.4199.940.11-0.22-0.06*p<0.05

Diagnosis of Periprosthetic Joint Infection Using Polymerase Chain Reaction: An Updated Systematic Review and Meta-Analysis.

We aim to update a meta-analysis to evaluate the efficiency of polymerase chain reaction (PCR) for diagnosis of periprosthetic joint infection (PJI) because different types of PCR assays have yielded variable diagnostic efficiency from 2013. We conducted our systematic review by searching for keywords in online databases from 2013 to May 2017. Studies were chosen based on inclusion and exclusion criteria and the quality of included studies was assessed. Pooled sensitivity and specificity were compared with other synovial fluid biomarkers. A total of 20 studies, comprising 2,526 participants were assessed. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were 0.76 (95% confidence interval [CI]: 0.65-0.85), 0.94 (95% CI: 0.92-0.95), and 0.94 (95% CI: 0.92-0.96), respectively. Meta-regression analysis indicated that use of specific genes, fresh samples, and more than one sample per patient may improve sensitivity. Although novel PCR assays have been developed, the sensitivity of PCR for the diagnosis of PJI had decreased compared with the previous meta-analysis (0.86, 95% CI: 0.77-0.92), whereas the high specificity is reliable for excluding PJI. Novel synovial fluid biomarker such as α-defensin, which possesses pooled sensitivity between 0.96 and 1.00, might be more efficient than PCR in PJI diagnosis.

Changes in biomarkers in equine synovial fluid two weeks after intra-articular hyaluronan treatment: a randomised double-blind clinical trial

BackgroundInflammatory and degenerative activity inside the joint can be studied in vivo via analysis of synovial fluid (SF) biomarkers, which are molecular markers of inflammatory processes and tissue turnover. The aim of this study was to investigate the response of selected biomarkers in the SF after an intra-articular (IA) high-molecular-weight non-animal stabilized hyaluronic acid (NASHA) treatment. Our hypothesis was that prostaglandin E2 (PGE2), substance P, aggrecan chondroitin sulfate 846 epitope (CS846), and carboxypeptide of type II collagen (CPII) concentrations in SF would decrease more in the NASHA than in the placebo group. Twenty-eight clinically lame horses with positive responses to diagnostic IA anaesthesia of the metacarpophalangeal or metatarsophalangeal joints were randomized into treatment (n = 15) and control (n = 13) groups. After collection of baseline SF samples followed by IA diagnostic anaesthesia, horses in the treatment group received 3 ml of a NASHA product IA. Those in the placebo group received an equivalent volume of sterile 0.9% saline solution. The horses were re-evaluated and a second SF sample was obtained after a 2-week period.ResultsCS846 concentration decreased in the NASHA group only (P = 0.010). Both PGE2 and CPII concentrations decreased within the groups (PGE2, P = 0.010 for the NASHA group; P = 0.027 for the placebo group; CPII, P < 0.001 for NASHA group; P = 0.009 for placebo group). No significant treatment effect for any biomarker was found between groups. NASHA induced an increase in white blood cell count; this was significant compared with baseline (P = 0.021) and the placebo group (P = 0.045).ConclusionsAlthough the SF concentration of the cartilage-derived biomarker CS846 decreased in the NASHA group, no statistically significant treatment effect of any of the biomarkers were observed between treatment groups. The significant increase in SF white blood cell count after IA NASHA may indicate a mild inflammatory response. However, as no clinical adverse effects were observed, we conclude that IA NASHA was well tolerated.

Sustained intra-articular release of celecoxib in an equine repeated LPS synovitis model

Synovial inflammation is an important characteristic of arthritic disorders like osteoarthritis and rheumatoid arthritis. Orally administered non-steroidal anti-inflammatory drugs (NSAIDs) such as celecoxib are among the most widely prescribed drugs to manage these debilitating diseases. Intra-articular delivery in biodegradable in situ forming hydrogels overcomes adverse systemic effects and prolongs drug retention in the joint.In this study two formulations of celecoxib (40 mg/g and 120 mg/g) in a propyl-capped PCLA-PEG-PCLA triblock copolymer were sequentially evaluated in a multiple LPS challenge equine synovitis model. Intra-articular release and systemic exposure to celecoxib and local changes at joint level were evaluated longitudinally.A single intra-articular injection of the high dose (HCLB)-gel or low dose (LCLB)-gel showed a sustained and controlled intra-articular release in both inflamed and healthy joints together with very low systemic exposure. Synovitis and lameness were moderate respectively very mild in this model due to the low concentration LPS (0.25 ng/joint). Both celecoxib formulations had a mild, transient effect on inflammatory and structural synovial fluid biomarkers but these returned to baseline within one week of administration. The HCLB-gel showed a significant inhibition in peak white blood cell concentration at 8 h after LPS induction.Elevated levels of celecoxib were observed in the joint for up to 30 days but no overall anti-inflammatory effects could be observed, which was thought to be due to the moderate synovitis. As there were no long-term adverse effects, sustained intra-articular release of celecoxib from in situ forming hydrogels should be evaluated further for its effects on longer-term relief of inflammatory joint pain in humans and animals.

Biomarkers of macrophage-associated inflammatory pathways are associated with OA symptoms and radiographic disease

Purpose: Although the role of inflammation in osteoarthritis has been heavily debated, recent evidence has demonstrated macrophage involvement in knee osteoarthritis (OA). Using etarfolatide (EC20) nuclear imaging that detects folate receptors, we have observed activated macrophages in human knee OA joints whose quantity are correlated with both radiographic and symptom severity of knee OA. In addition, we identified synovial fluid (SF) biomarkers, CD163 and CD14, that function as quantitative traits of the etarfolatide-positive phenotype and that predict knee OA progression over 3 years, allowing for the identification of inflammatory OA phenotypes. The purpose of this study was to characterize a molecular biological profile for identifying subsets of subjects with an inflammatory OA phenotype through the investigation of the association of an extensive array of synovial fluid biomarkers with the severity of macrophage infiltration, radiographic knee OA and pain. Methods: The Institutional Review Board approved all procedures and the study was registered at ClinicalTrials.gov (NCT01237405). Participants (n = 25) with radiographic knee OA in at least one knee and knee pain underwent bilateral knee etarfolatide imaging. SF was obtained by either direct aspiration (n = 28 knees) or by lavage (n = 20 knees) when direct aspiration was not possible. Samples were stored at -80 until analyzed. The intensity of etarfolatide imaging of the knee and pain assessment by NHANES criteria were scored semi-quantitatively as normal (score 0), mild (score 1), moderate (score 2), or severe (score 3). Radiographs were scored for Kellgren Lawrence (KL) grade (0-4), joint space narrowing (JSN, 0-3) and osteophyte (OST, 0-3). Biomarkers were quantified by Rules Based Medicine (RBM) using the high sensitivity multiplex immunoassay, Myriad Human InflammationMAP 1.0, including 47 different cytokines, chemokines, and growth factors related to inflammation. Biomarker concentrations in lavage fluid were corrected for dilution by an established urea method. Multivariable linear regression models using generalized estimating equations (GEEs) were performed to evaluate associations of biomarker concentrations with etarfolatide scores, radiographic OA severity, and OA symptoms, adjusting for age, gender and BMI. False discovery rate (FDR) was controlled using the Benjamini-Hochberg method. Spearman correlations were used to test for associations of informative RBM markers with sfCD163 and sfCD14. Results: Participants were 72% female, mean age of 62.4 (range 30-89) and a mean BMI of 29.2 (range 22.5-38.4 kg/m2). The majority (76%) of participants had moderate to severe bilateral radiographic knee OA with 24% having a KL grade 1, 58% KL grade 2-3, and 18% KL grade 4. Significant associations of SF biomarkers included sVCAM-1 and MMP-3 with the presence of activated macrophages (etarfolatide scan), sVCAM-1, sICAM-1, TIMP-1, and VEGF with radiographic OA severity (KL, JSN, and OST), and VEGF, MMP-3, TIMP-1, sICAM-1, sVCAM-1, and MCP-1 with OA symptoms (Table 1). These SF biomarkers were all highly correlated with sfCD163 and sfCD14. Conclusions: This study provides evidence in support of an inflammatory OA subphenotype characterized by the presence of activated macrophages and its association with synovial fluid biomarkers of inflammation and angiogenesis. These processes may interrelate as VEGF, a biomarker of angiogenesis, can increase expression of MMPs and inflammation, and markers of vascular adhesion, VCAM-1 and ICAM-1 correlate with synovitis. This biomarker profile may assist in identifying patients with an inflammatory OA phenotype for targeting of treatment to modulate inflammation and activated macrophages.

Identification of tissue-specific biomarkers in knee osteoarthritis synovial fluid: a proteomic approach

Identification of tissue-specific biomarkers in knee osteoarthritis synovial fluid: a proteomic approach

Colchicine lack of effectiveness in symptom and inflammation modification in knee osteoarthritis (COLKOA): a randomized controlled trial

Uric acid may activate an innate immune response in osteoarthritis (OA), contributing to disease pathology and progression. We evaluated the effectiveness of colchicine on pain and function in symptomatic knee OA (KOA) and the underlying mechanism of action. Colchicine effectiveness in symptoms and inflammation modification in knee osteoarthritis (COLKOA) was a double-blind, placebo-controlled, randomized trial comparing 16 weeks of treatment with 0.5mg twice-daily oral colchicine to placebo for knee osteoarthritis (KOA). The primary endpoint was ≥30% improvement in total Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at week 16. Secondary endpoints included improvement in pain (0-10 Likert scales); WOMAC pain; patient global assessment (0-100); physical function; the OARSI-OMERACT response; quality of life; and change in serum, urine, synovial fluid (SF) biomarkers of cartilage metabolism and inflammation, and plasma/SF colchicine concentrations. Of 109 randomly assigned participants, 39% (95% confidence interval (CI) 27-52%) and 49% (95% CI 36-62%) in the colchicine and placebo arms respectively met the primary endpoint at study end (P=0.284, odds ratio 0.66, 95% CI 0.31-1.41). No strong evidence of treatment differences was identified on clinical secondary endpoints. Treatment significantly reduced mean serum hs-CRP (P=0.008) and SF CTXI (P=0.002); treatment tended to reduce inflammatory markers (SF IL-6, IL8, TNFα, CD14 and IL-18), but these differences were not statistically significant. Colchicine (0.5mg twice-daily orally) reduced inflammation and high bone turnover biomarkers known to be associated with OA severity and progression risk, but did not reduce KOA symptoms over a 16-week study period. A longer-term study to evaluate for slow-acting disease modifying effects is warranted. The trial has been registered at clinicaltrials.gov as NCT02176460. Date of registration: June 26, 2014.

Synovial Fluid Profile at the Time of Anterior Cruciate Ligament Reconstruction and Its Association With Cartilage Matrix Composition 3 Years After Surgery

Background: Anterior cruciate ligament tears can lead to posttraumatic osteoarthritis. In addition to biomechanical factors, changes in biochemical profiles within the knee joint after injury and anterior cruciate ligament reconstruction (ACLR) may play a role in accelerating joint degeneration. Hypothesis/Purpose: It was hypothesized that cartilage matrix composition after ACLR is associated with the degree of inflammatory response after initial injury. This study evaluated the association between the inflammatory response after injury—as indicated by cytokine, metalloproteinase, and cartilage degradation marker concentrations in synovial fluid—and articular cartilage degeneration, measured by T1ρ and T2 quantitative magnetic resonance imaging up to 3 years after ACLR. Study Design: Cohort study; Level of evidence, 2. Methods: Twenty-six subjects from a longitudinal cohort study who underwent ACLR at a mean 8.5 weeks after injury (range, 4-19 weeks) had synovial fluid aspirated at the time of surgery. Immunoassays quantified biomarkers in synovial fluid. T1ρ and T2 values of articular cartilage were calculated with magnetic resonance scans acquired prior to surgery and at 6 months and 1, 2, and 3 years after surgery. Pearson correlation coefficients were calculated among the various biomarkers. K-means clustering was used to group subjects with similar biomarker profiles. Generalized estimating equations were used to find the overall differences in T1ρ and T2 values throughout these first 3 years after surgery between the clusters while controlling for other factors. Results: Significant and strong correlations were observed between several cytokines (interleukin 6 [IL-6], IL-8, IL-10, and tumor necrosis factor α) and 2 matrix metalloproteinases (MMP-1 and MMP-3) (P < .05). Moderate correlations were found among combinations of C-terminal crosslinked telopeptide type II collagen, N-terminal telopeptide, cartilage oligomeric matrix protein, and sulfated glycosaminoglycan (P < .05). Two clusters were generated, 1 of which was characterized by lower concentrations of cytokines (IL-6, IL-8, IL-10, tumor necrosis factor α) and MMP-1 and MMP-3 and higher sulfated glycosaminoglycan. This cluster was associated with significantly higher T1ρ and T2 values in the medial tibial and patellar cartilage over the first 3 years after ACLR. Conclusion: At the time of ACLR surgery, profiles of synovial fluid inflammatory cytokines, degradative enzymes, and cartilage breakdown products show promise as predictors of abnormal cartilage tissue integrity (increased T1ρ and T2 values) throughout the first 3 years after surgery. Clinical Relevance: The results suggest an intricate relationship between inflammation and cartilage turnover, which can in turn be influenced by timing after injury and patient factors.

An Alternative Macrophage Activation Pathway Regulator, CHIT1, May Provide a Serum and Synovial Fluid Biomarker of Periprosthetic Osteolysis

BackgroundPeriprosthetic osteolysis (PPO) is a frequent indication for total hip replacement (THR) failure. Currently, PPO diagnosis occurs in advanced stages that often necessitate complex revisions due to bone loss. PPO biomarkers could facilitate earlier diagnosis. Alternative macrophage activation pathway regulators, chitotriosidase (CHIT1) and CC chemokine ligand 18 (CCL18), have increased periprosthetic expression in patients undergoing revision THR for osteolysis. We hypothesized that synovial fluid and serum levels of CHIT1 and CCL18 would be increased in patients undergoing revision THR for PPO versus controls without osteolysis.MethodsIn this prospective case-control study, 60 patients undergoing revision metal-on-polyethylene THR at Hospital for Special Surgery were screened preoperatively from January 2013 to December 2014. Twenty “osteolysis” patients who underwent revision for PPO (based on imaging and operative reports) and 10 “control” patients (with stable implants) who underwent revision for recurrent dislocation or a mechanical etiology were included. Among osteolysis and control patients, 11/20 and 4/10 were male; average age was 68 and 63 years, respectively; 9/20 and 3/10 had cemented femoral components; and average implant longevity was 15 and 5 years, respectively. Preoperative serum and intraoperative synovial fluid samples were collected. CHIT1 and CCL18 were quantified via enzyme-linked immunosorbent assay. Significance was assessed via nonparametric Mann-Whiney U test.ResultsCHIT1 was significantly increased in both synovial fluid (3727 versus 731 nanomoles [nM]) and serum (98 versus 39 nM) in the osteolysis versus control patients. CCL18 levels were also significantly increased in osteolysis versus control patients’ synovial fluid (425 versus 180 nM) but not their serum.ConclusionsIn this prospective case-control study, CHIT1 was identified as a novel synovial fluid and serum biomarker of PPO. CHIT1 expression is induced during macrophage activation in response to wear debris. CHIT1 monitoring may facilitate early diagnosis of THR PPO. Furthermore, CHIT1 may represent a novel therapeutic target for PPO.