Test-retest precision and longitudinal cartilage thickness loss in the IMI-APPROACH cohort.

OBJECTIVE: To investigate the test-retest precision and to report the longitudinal change in cartilage thickness, the percentage of knees with progression and the predictive value of the machine-learning-estimated structural progression score (s-score) for cartilage thickness loss in the IMI-APPROACH cohort - an exploratory, 5-center, 2-year prospective follow-up cohort. DESIGN: Quantitative cartilage morphology at baseline and at least one follow-up visit was available for 270 of the 297 IMI-APPROACH participants (78% females, age: 66.4 ± 7.1 years, body mass index (BMI): 28.1 ± 5.3 kg/m2, 55% with radiographic knee osteoarthritis (OA)) from 1.5T or 3T MRI. Test-retest precision (root mean square coefficient of variation) was assessed from 34 participants. To define progressor knees, smallest detectable change (SDC) thresholds were computed from 11 participants with longitudinal test-retest scans. Binary logistic regression was used to evaluate the odds of progression in femorotibial cartilage thickness (threshold: -211 µm) for the quartile with the highest vs the quartile with the lowest s-scores. RESULTS: The test-retest precision was 69 µm for the entire femorotibial joint. Over 24 months, mean cartilage thickness loss in the entire femorotibial joint reached -174 µm (95% CI: [-207, -141] µm, 32.7% with progression). The s-score was not associated with 24-month progression rates by MRI (OR: 1.30, 95% CI: [0.52, 3.28]). CONCLUSION: IMI-APPROACH successfully enrolled participants with substantial cartilage thickness loss, although the machine-learning-estimated s-score was not observed to be predictive of cartilage thickness loss. IMI-APPROACH data will be used in subsequent analyses to evaluate the impact of clinical, imaging, biomechanical and biochemical biomarkers on cartilage thickness loss and to refine the machine-learning-based s-score. GOV IDENTIFICATION: NCT03883568.

Subchondral bone changes after joint distraction treatment for end stage knee osteoarthritis.

OBJECTIVE: Increased subchondral cortical bone plate thickness and trabecular bone density are characteristic of knee osteoarthritis (OA). Knee joint distraction (KJD) is a joint-preserving knee OA treatment where the joint is temporarily unloaded. It has previously shown clinical improvement and cartilage regeneration, indicating reversal of OA-related changes. The purpose of this research was to explore 3D subchondral bone changes after KJD treatment using CT imaging. DESIGN: Twenty patients were treated with KJD and included to undergo knee CT imaging before, one, and two years after treatment. Tibia and femur segmentation and registration to canonical surfaces were performed semi-automatically. Cortical bone thickness and trabecular bone density were determined using an automated algorithm. Statistical parametric mapping (SPM) with two-tailed F-tests was used to analyze whole-joint changes. RESULTS: Data was available of 16 patients. Subchondral cortical bone plate thickness and trabecular bone density were higher in the weight-bearing region of the most affected compartment (MAC; mostly medial). Especially the MAC showed a decrease in thickness and density in the first year after treatment, which was sustained towards the second year. CONCLUSIONS: KJD treatment results in bone changes that include thinning of the subchondral cortical bone plate and decrease of subchondral trabecular bone density in the first two years after treatment, potentially indicating a partial normalization of subchondral bone.

The association of the lipid profile with knee and hand osteoarthritis severity: the IMI-APPROACH cohort.

OBJECTIVE: To investigate the association of the lipidomic profile with osteoarthritis (OA) severity, considering the outcomes radiographic knee and hand OA, pain and function. DESIGN: We used baseline data from the Applied Public-Private Research enabling OsteoArthritis Clinical Headway (APPROACH) cohort, comprising persons with knee OA fulfilling the clinical American College of Rheumatology classification criteria. Radiographic knee and hand OA severity was quantified with Kellgren-Lawrence sum scores. Knee and hand pain and function were assessed with validated questionnaires. We quantified fasted plasma higher order lipids and oxylipins with liquid chromatography with tandem mass spectrometry (LC-MS/MS)-based platforms. Using penalised linear regression, we assessed the variance in OA severity explained by lipidomics, with adjustment for clinical covariates (age, sex, body mass index (BMI) and lipid lowering medication), measurement batch and clinical centre. RESULTS: In 216 participants (mean age 66 years, mean BMI 27.3 kg/m2, 75% women) we quantified 603 higher order lipids (triacylglycerols, diacylglycerols, cholesteryl esters, ceramides, free fatty acids, sphingomyelins, phospholipids) and 28 oxylipins. Lipidomics explained 3% and 2% of the variance in radiographic knee and hand OA severity, respectively. Lipids were not associated with knee pain or function. Lipidomics accounted for 12% and 6% of variance in hand pain and function, respectively. The investigated OA severity outcomes were associated with the lipidomic fraction of bound and free arachidonic acid, bound palmitoleic acid, oleic acid, linoleic acid and docosapentaenoic acid. CONCLUSIONS: Within the APPROACH cohort lipidomics explained a minor portion of the variation in OA severity, which was most evident for the outcome hand pain. Our results suggest that eicosanoids may be involved in OA severity.

The molecular profile of synovial fluid changes upon joint distraction and is associated with clinical response in knee osteoarthritis.

OBJECTIVE: Surgical knee joint distraction (KJD) leads to clinical improvement in knee osteoarthritis (OA) and also apparent cartilage regeneration by magnetic resonance imaging. We investigated if alteration of the joint's mechanical environment during the 6 week period of KJD was associated with a molecular response in synovial fluid, and if any change was associated with clinical response. METHOD: 20 individuals undergoing KJD for symptomatic radiographic knee OA had SF sampled at baseline, midpoint and endpoint of distraction (6 weeks). SF supernatants were measured by immunoassay for 10 predefined mechanosensitive molecules identified in our previous pre-clinical studies. The composite Knee injury and OA Outcome Score-4 (KOOS4) was collected at baseline, 3, 6 and 12 months. RESULTS: 13/20 (65%) were male with mean age 54°±°5yrs. All had Kellgren-Lawrence grade ≥2 knee OA. 6/10 analytes showed statistically significant change in SF over the 6 weeks distraction (activin A; TGFß-1; MCP-1; IL-6; FGF-2; LTBP2), P < 0.05. Of these, all but activin A increased. Those achieving the minimum clinically important difference of 10 points for KOOS4 over 6 months showed greater increases in FGF-2 and TGFß-1 than non-responders. An increase in IL-8 during the 6 weeks of KJD was associated with significantly greater improvement in KOOS4 over 12 months. CONCLUSION: Detectable, significant molecular changes are observed in SF following KJD, that are remarkably consistent between individuals. Preliminary findings appear to suggest that increases in some molecules are associated with clinically meaningful responses. Joint distraction may provide a potential opportunity in the future to define regenerative biomarker(s) and identify pathways that drive intrinsic cartilage repair.

IL4-10 fusion protein: a novel immunoregulatory drug combining activities of interleukin 4 and interleukin 10.

The objective of this study was to test the capacity of a newly developed fusion protein of interleukin 4 (IL-4) and IL-10 [IL4-10 fusion protein (FP)] to shift multiple pro-inflammatory pathways towards immune regulation, and to inhibit pro-inflammatory activity in arthritis models. The effects of IL4-10 FP in comparison with IL-4, IL-10 and IL-4 plus IL-10 on pro- and anti-inflammatory mediators, T cells and immunoglobulin (Ig) receptors in favour of immunoregulatory activity were studied. In addition, the capacity of IL4-10 FP to inhibit pro-inflammatory activity in ex-vivo and in-vivo arthritis models was investigated. IL4-10 FP robustly inhibited pro-inflammatory cytokine [IL-1ß, tumour necrosis factor (TNF)-α, IL-6 and IL-8] production in whole blood cultures, mediated by both the IL-10 and the IL-4 moiety. IL4-10 fusion protein induced IL-1 receptor antagonist (IL-1RA) production and preserved soluble TNF receptor (sTNFR) levels, strongly increasing IL-1RA/IL-1ß and sTNFR/TNF-α ratios. In addition, IL4-10 FP strongly inhibited T helper (Th) type 1 and 17 cytokine secretion, while maintaining FoxP3 expression and up-regulating Th2 activity. In addition, while largely leaving expression of activating Fc gamma receptor (FcγR)I, III and Fc epsilon receptor (FcεR) unaffected, it significantly shifted the FcγRIIa/FcγRIIb ratio in favour of the inhibitory FcγRIIb. Moreover, IL4-10 FP robustly inhibited secretion of pro-inflammatory cytokines by rheumatoid arthritis synovial tissue and suppressed experimental arthritis in mice, without inducing B cell hyperactivity. IL4-10 fusion protein is a novel drug, signalling cells to induce immunoregulatory activity that overcomes limitations of IL-4 and IL-10 stand-alone therapy, and therefore has therapeutic potential for inflammatory diseases such as rheumatoid arthritis.

Human C-reactive protein aggravates osteoarthritis development in mice on a high-fat diet.

OBJECTIVE: C-reactive protein (CRP) levels can be elevated in osteoarthritis (OA) patients. In addition to indicating systemic inflammation, it is suggested that CRP itself can play a role in OA development. Obesity and metabolic syndrome are important risk factors for OA and also induce elevated CRP levels. Here we evaluated in a human CRP (hCRP)-transgenic mouse model whether CRP itself contributes to the development of 'metabolic' OA. DESIGN: Metabolic OA was induced by feeding 12-week-old hCRP-transgenic males (hCRP-tg, n = 30) and wild-type littermates (n = 15) a 45 kcal% high-fat diet (HFD) for 38 weeks. Cartilage degradation, osteophytes and synovitis were graded on Safranin O-stained histological knee joint sections. Inflammatory status was assessed by plasma lipid profiling, flow cytometric analyses of blood immune cell populations and immunohistochemical staining of synovial macrophage subsets. RESULTS: Male hCRP-tg mice showed aggravated OA severity and increased osteophytosis compared with their wild-type littermates. Both classical and non-classical monocytes showed increased expression of CCR2 and CD86 in hCRP-tg males. HFD-induced effects were evident for nearly all lipids measured and indicated a similar low-grade systemic inflammation for both genotypes. Synovitis scores and synovial macrophage subsets were similar in the two groups. CONCLUSIONS: Human CRP expression in a background of HFD-induced metabolic dysfunction resulted in the aggravation of OA through increased cartilage degeneration and osteophytosis. Increased recruitment of classical and non-classical monocytes might be a mechanism of action through which CRP is involved in aggravating this process. These findings suggest interventions selectively directed against CRP activity could ameliorate metabolic OA development.

Effectiveness of Remission Induction Strategies for Early Rheumatoid Arthritis: a Systematic Literature Review.

PURPOSE OF REVIEW: To review the effectiveness of remission induction strategies compared to single csDMARD-initiating strategies according to current guidelines in early RA. RECENT FINDINGS: Twenty-nine studies, heterogeneous on, e.g., specific treatment strategy and remission outcome used, were identified. Using DAS28-remission over 12 months, 13 (76%) of 17 remission induction strategies showed significantly more patients achieving remission. Pooled relative "risk" was 1.73 [95%CI 1.59-1.88] for bDMARD-based remission induction strategies and 1.20 [95%CI 1.03-1.40] for combination csDMARD-based remission induction strategies compared to single csDMARD-initiating strategies. When additional glucocorticoid "bridging therapy" was used in single csDMARD-initiating strategies, the higher proportion patients achieving remission in remission induction strategies was no longer statistically significant (pooled RR 1.06 [95%CI 0.83-1.35]). For other remission outcomes, results were in line with above. Remission induction strategies are more effective in achieving remission compared to single csDMARD-initiating strategies, possibly more so in bDMARD-based induction strategies. However, compared to single csDMARD-initiating strategies with glucocorticoids, induction strategies may not be more effective.

Initial tissue repair predicts long-term clinical success of knee joint distraction as treatment for knee osteoarthritis.

OBJECTIVE: Knee joint distraction (KJD), a joint-preserving surgery for severe osteoarthritis (OA), provides clinical and structural improvement and postpones the need for total knee arthroplasty (TKA). This study evaluates 9-year treatment outcome and identifies characteristics predicting long-term treatment success. DESIGN: Patients with severe tibiofemoral OA (n = 20; age<60 years) indicated for TKA were treated with KJD. Questionnaires, radiographs, and magnetic resonance imaging (MRI) were used for evaluation. Survival after treatment was analyzed, where 'failure' was defined by TKA over time. RESULTS: 9-year survival was 48%, and 72% for men (compared to 14% for women; P = 0.035) and 73% for those with a first-year minimum joint space width (JSW) increase of >0.5 mm (compared to 0% for <0.05 mm; P = 0.002). Survivors still reported clinical improvement compared to baseline (ΔWOMAC +29.9 points (95%CI 16.9-42.9; P = 0.001), ΔVAS -46.8 mm (-31.6-61.9; P < 0.001)). Surprisingly, patients getting TKA years after KJD still reported clinical improvement although less pronounced (ΔWOMAC +20.5 points (-1.8-42.8; P = 0.067), ΔVAS -25.4 mm (-3.2-47.7; P = 0.030)). Survivors showed long-lasting minimum JSW increase (baseline 0.3 mm (IQR 1.9), follow-up 1.3 mm (2.5); P = 0.017) while 'failures' did not (baseline 0.4 mm (1.8), follow-up 0.2 mm (1.5); P = 0.161). First-year minimum JSW on radiographs and cartilage thickness increase on MRI predict 9-year survival (HR 0.05 and 0.12, respectively; both P < 0.026). Male gender was associated with survival (HR 0.24; P = 0.050). CONCLUSIONS: KJD shows long-lasting clinical and structural improvement. In addition to a greater survival rate for males (>two out of three), the initial cartilage repair activity appears to be important for long-term clinical success.

Disease burden of knee osteoarthritis patients with a joint replacement compared to matched controls: a population-based analysis of a Dutch medical claims database.

OBJECTIVE: On a population level, the incidence of knee prostheses (KPs) has increased, but excess health care costs per patient, compared to matched controls without a KP, in the years surrounding these procedures and their determinants are largely unknown. We therefore aimed to provide estimates of age- and sex-specific incidence of KPs, revision KPs, and prosthesis complications in patients with knee osteoarthritis (OA) and to determine excess health care costs in the years surrounding surgery compared with matched controls. METHODS: All KPs in OA patients in the Achmea Health Database were identified as well as up to four controls. Incidence rates of KPs, revisions, and complications from 2006 to 2013 were determined. Annual health care cost and excess costs (over matched controls) preceding, during, and after surgery were calculated and their determinants were evaluated. RESULTS: The increased incidence of KPs, revisions, and complications was strongest in younger age categories and men. The average costs per patient were relatively stable between 2006 and 2012. KP patient's annual health care costs increased towards the year of surgery. After surgery, costs decreased, but remained higher as compared to costs prior to surgery. High post-surgery costs were mainly associated with subsequent revisions or additional KPs, but costs were also higher in females, lower age categories, and lower social economic status. CONCLUSION: These results underscore the increasing burden and medical need associated with end-stage OA, especially in younger age categories. Improvement of guidelines tailored to individual patient groups aimed at avoiding complications and revisions is required to counteract this increasing burden.

IL4-10 fusion protein has chondroprotective, anti-inflammatory and potentially analgesic effects in the treatment of osteoarthritis.

OBJECTIVE: Effective disease-modifying drugs for osteoarthritis (DMOAD) should preferably have chondroprotective, anti-inflammatory, and analgesic activity combined in a single molecule. We developed a fusion protein of IL4 and IL10 (IL4-10 FP), in which the biological activity of both cytokines is preserved. The present study evaluates the chondroprotective, anti-inflammatory, and analgesic activity of IL4-10 FP in in vitro and in vivo models of osteoarthritis. METHODS: Human osteoarthritic cartilage tissue and synovial tissue were cultured with IL4-10 FP. Cartilage proteoglycan turnover and release of pro-inflammatory, catabolic, and pain mediators by cartilage and synovial tissue were measured. The analgesic effect of intra-articularly injected IL4-10 FP was evaluated in a canine model of osteoarthritis by force-plate analysis. RESULTS: IL4-10 FP increased synthesis (P = 0.018) and decreased release (P = 0.018) of proteoglycans by osteoarthritic cartilage. Release of pro-inflammatory IL6 and IL8 by cartilage and synovial tissue was reduced in the presence of IL4-10 FP (all P < 0.05). The release of MMP3 by osteoarthritic cartilage and synovial tissue was decreased (P = 0.018 and 0.028) whereas TIMP1 production was not significantly changed. Furthermore, IL4-10 FP protected cartilage against destructive properties of synovial tissue mediators shown by the increased cartilage proteoglycan synthesis (P = 0.0235) and reduced proteoglycan release (P = 0.0163). Finally, intra-articular injection of IL4-10 FP improved the deficient joint loading in dogs with experimentally induced osteoarthritis. CONCLUSION: The results of current preliminary study suggest that IL4-10 FP has DMOAD potentials since it shows chondroprotective and anti-inflammatory effects in vitro, as well as potentially analgesic effect in a canine in vivo model of osteoarthritis.

Variable cartilage degradation in mice with diet-induced metabolic dysfunction: food for thought.

OBJECTIVE: Human cohort studies have demonstrated a role for systemic metabolic dysfunction in osteoarthritis (OA) pathogenesis in obese patients. To explore the mechanisms underlying this metabolic phenotype of OA, we examined cartilage degradation in the knees of mice from different genetic backgrounds in which a metabolic phenotype was established by various dietary approaches. DESIGN: Wild-type C57BL/6J mice and genetically modified mice (hCRP, LDLr-/-. Leiden and ApoE*3Leiden.CETP mice) based on C57BL/6J background were used to investigate the contribution of inflammation and altered lipoprotein handling on diet-induced cartilage degradation. High-caloric diets of different macronutrient composition (i.e., high-carbohydrate or high-fat) were given in regimens of varying duration to induce a metabolic phenotype with aggravated cartilage degradation relative to controls. RESULTS: Metabolic phenotypes were confirmed in all studies as mice developed obesity, hypercholesteremia, glucose intolerance and/or insulin resistance. Aggravated cartilage degradation was only observed in two out of the twelve experimental setups, specifically in long-term studies in male hCRP and female ApoE*3Leiden.CETP mice. C57BL/6J and LDLr-/-. Leiden mice did not develop HFD-induced OA under the conditions studied. Osteophyte formation and synovitis scores showed variable results between studies, but also between strains and gender. CONCLUSIONS: Long-term feeding of high-caloric diets consistently induced a metabolic phenotype in various C57BL/6J (-based) mouse strains. In contrast, the induction of articular cartilage degradation proved variable, which suggests that an additional trigger might be necessary to accelerate diet-induced OA progression. Gender and genetic modifications that result in a humanized pro-inflammatory state (human CRP) or lipoprotein metabolism (human-E3L.CETP) were identified as important contributing factors.

Differential effects of bleeds on the development of arthropathy - basic and applied issues.

Haemophilia is characterized by a spontaneous bleeding tendency, affecting mainly the synovial joints. Recurrent joint bleeds induce a cascade of inflammatory as well as degenerative processes injuring synovium, cartilage and bone. These processes affect each other and may occur in parallel and/or sequentially. Clinically, the effects of joint bleeds are heterogeneous. A marked variability in joint damage is observed in patients with a similar bleeding history. Also late stage effects differ with some patients developing chronic synovitis, and others suffering from osteochondral degeneration called haemophilic arthropathy. This article reviews the current understanding of the pathogenesis of blood-induced joint damage, elaborates on potential explanations for the differential effects of a bleed, and discusses challenges for future research.

Knee joint distraction compared with high tibial osteotomy: a randomized controlled trial.

PURPOSE: Both, knee joint distraction as a relatively new approach and valgus-producing opening-wedge high tibial osteotomy (HTO), are knee-preserving treatments for knee osteoarthritis (OA). The efficacy of knee joint distraction compared to HTO has not been reported. METHODS: Sixty-nine patients with medial knee joint OA with a varus axis deviation of <10° were randomized to either knee joint distraction (n = 23) or HTO (n = 46). Questionnaires were assessed at baseline and 3, 6, and 12 months. Joint space width (JSW) as a surrogate measure for cartilage thickness was determined on standardized semi-flexed radiographs at baseline and 1-year follow-up. RESULTS: All patient-reported outcome measures (PROMS) improved significantly over 1 year (at 1 year p < 0.02) in both groups. At 1 year, the HTO group showed slightly greater improvement in 4 of the 16 PROMS (p < 0.05). The minimum medial compartment JSW increased 0.8 ± 1.0 mm in the knee joint distraction group (p = 0.001) and 0.4 ± 0.5 mm in the HTO group (p < 0.001), with minimum JSW improvement in favour of knee joint distraction (p = 0.05). The lateral compartment showed a small increase in the knee joint distraction group and a small decrease in the HTO group, leading to a significant increase in mean JSW for knee joint distraction only (p < 0.02). CONCLUSION: Cartilaginous repair activity, as indicated by JSW, and clinical outcome improvement occurred with both, knee joint distraction and HTO. These findings suggest that knee joint distraction may be an alternative therapy for medial compartmental OA with a limited mechanical leg malalignment. LEVEL OF EVIDENCE: Randomized controlled trial, Level I.

Alarmins S100A8/S100A9 aggravate osteophyte formation in experimental osteoarthritis and predict osteophyte progression in early human symptomatic osteoarthritis.

OBJECTIVE: Alarmins S100A8 and S100A9 are major products of activated macrophages regulating cartilage damage and synovial activation during murine and human osteoarthritis (OA). In the current study, we investigated whether S100A8 and S100A9 are involved in osteophyte formation during experimental OA and whether S100A8/A9 predicts osteophyte progression in early human OA. METHODS: OA was elicited in S100A9-/- mice in two experimental models that differ in degree of synovial activation. Osteophyte size, S100A8, S100A9 and VDIPEN neoepitope was measured histologically. Chondrogenesis was induced in murine mesenchymal stem cells in the presence of S100A8. Levels of S100A8/A9 were determined in plasma of early symptomatic OA participants of the Cohort Hip and Cohort Knee (CHECK) cohort study and osteophytes measured after 2 and 5 years. RESULTS: Osteophyte size was drastically reduced in S100A9-/- mice in ligaments and at medial femur and tibia on days 21 and 42 of collagenase-induced OA, in which synovial activation is high. In contrast, osteophyte size was not reduced in S100A9-/- mice during destabilised medial meniscus OA, in which synovial activation is scant. S100A8 increased expression and activation of matrix metalloproteinases during micromass chondrogenesis, thereby possibly increasing cartilage matrix remodelling allowing for larger osteophytes. Interestingly, early symptomatic OA participants of the CHECK study with osteophyte progression after 2 and 5 years had elevated S100A8/A9 plasma levels at baseline, while C-reactive protein, erythrocyte sedimentation rate and cartilage oligomeric matrix protein were not elevated at baseline. CONCLUSIONS: S100A8/A9 aggravate osteophyte formation in experimental OA with high synovial activation and may be used to predict osteophyte progression in early symptomatic human OA.

Comparative lipidomic analysis of synovial fluid in human and canine osteoarthritis.

OBJECTIVE: The lipid profile of synovial fluid (SF) is related to the health status of joints. The early stages of human osteoarthritis (OA) are poorly understood, which larger animals are expected to be able to model closely. This study examined whether the canine groove model of OA represents early OA in humans based on the changes in the lipid species profile in SF. Furthermore, the SF lipidomes of humans and dogs were compared to determine how closely canine lipid species profiles reflect the human lipidome. METHODS: Lipids were extracted from cell- and cellular debris-free knee SF from nine donors with healthy joints, 17 patients with early and 13 patients with late osteoarthritic changes, and nine dogs with knee OA and healthy contralateral joints. Lipid species were quantified by electrospray ionization tandem mass spectrometry (ESI-MS/MS). RESULTS: Compared with control canine SF most lipid species were elevated in canine OA SF. Moreover, the lipid species profiles in the canine OA model resembled early OA profiles in humans. The SF lipidomes between dog and human were generally similar, with differences in certain lipid species in the phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and sphingomyelin (SM) classes. CONCLUSIONS: Our lipidomic analysis demonstrates that SF in the canine OA model closely mimics the early osteoarthritic changes that occur in humans. Further, the canine SF lipidome often reflects normal human lipid metabolism.

Silencing of protease-activated receptors attenuates synovitis and cartilage damage following a joint bleed in haemophilic mice.

INTRODUCTION AND AIM: Joint bleeding results in blood-induced arthropathy. We investigate whether a joint bleed alters protease-activated receptor (PAR) expression, and whether treatment with small interfering RNA (siRNA) targeted against PAR1-4 attenuates synovitis and cartilage damage. METHODS: Protease-activated receptor expression was evaluated upon a joint bleed in haemophilic mice and in humans. In addition, mice with a joint bleed were randomized between treatment with PAR1-4 siRNA or control and evaluated for the presence of synovitis and cartilage damage. Also, human cartilage was transfected with PAR1-4 siRNA or control, and evaluated for plasmin-induced cartilage damage. RESULTS: Following a joint bleed, we observed an increase in synovial PAR1, -2 and -4 expression, and an increase in chondrocyte PAR2 and -3 expression in mice (all P < 0.05). Also an increase in synovial PAR1 and chondrocyte PAR4 expression in patients was observed (both P < 0.05). Treatment of a joint bleed in haemophilic mice with PAR1-4 siRNA attenuates synovitis and cartilage damage (both P < 0.01). Treatment of human cartilage tissue explants with PAR1-4 siRNA reduced plasmin-induced cartilage damage (P < 0.01). CONCLUSION: This study demonstrates that synovial and chondrocyte PAR expression is altered upon a joint bleed, and that treatment with PAR1-4 siRNA attenuates synovitis and plasmin-induced cartilage damage.

Personalised treatment using serum drug levels of adalimumab in patients with rheumatoid arthritis: an evaluation of costs and effects.

OBJECTIVE: To evaluate the cost-effectiveness of personalised treatment for rheumatoid arthritis (RA) using clinical response and serum adalimumab levels. METHODS: A personalised treatment algorithm defined, based on clinical (European League Against Rheumatism) response and drug levels at 6 months, whether adalimumab treatment should be continued in a specific dose or discontinued and/or switched to a next biological. Outcomes were simulated using a patient level Markov model, with 3 months cycles, based on a cohort of 272 adalimumab-treated patients with RA for 3 years and data of patients from the Utrecht Rheumatoid Arthritis Cohort. Costs, clinical effectiveness and quality adjusted life years (QALYs) were compared with outcomes as observed in usual care and incremental cost-effectiveness ratios were calculated. Analyses were performed probabilistically. RESULTS: Clinical effectiveness was higher for the cohort simulated to receive personalised care compared with usual care; the average difference in QALYs was 3.84 (95 percentile range -8.39 to 16.20). Costs were saved on drugs: €2 314 354. Testing costs amounted to €10 872. Mean total savings were €2 561 648 (95 percentile range -3 252 529 to -1 898 087), resulting in an incremental cost-effectiveness ratio of €666 500 or €646 266 saved per QALY gained from a societal or healthcare perspective, respectively. In 72% of simulations personalised care saved costs and resulted in more QALYs, in 28% it was cost saving with lower QALYs. Scenario analyses showed cost saving along with QALYs gain or limited loss. CONCLUSIONS: Tailoring biological treatment to individual patients with RA starting adalimumab using drug levels and short-term outcome is cost-effective. Results underscore the potential merit of personalised biological treatment in RA.

Associations of markers of matrix metabolism, inflammation markers, and adipokines with superior cam deformity of the hip and their relation with future hip osteoarthritis.

OBJECTIVE: First, to study how markers of matrix metabolism, inflammation markers, and adipokines relate to (superior) cam deformity and (possible) cam impingement of the hip. Second, to investigate whether they can identify subjects with cam deformity that are at risk of future hip osteoarthritis (OA). METHOD: In a cohort of 1002 subjects (CHECK), (superior) cam deformity was defined by an alpha angle >60° on anteroposterior pelvic radiographs and (possible) cam impingement by a cam deformity together with internal hip rotation ≤20°. Hip OA at 5-year follow-up was defined by Kellgren and Lawrence grade ≥2 or total hip replacement. RESULTS: Subjects with (superior) cam deformity and (possible) cam impingement showed lower levels of bone turnover markers (uCTX-I, uNTX-I, sPINP, sOC) than those without. Cam deformity was positively associated with future hip OA, but associations were weaker at high levels of bone turnover. sCOMP and sHA levels were higher in subjects with cam deformity, while other cartilage and synovium markers were not. Some markers of inflammation (pLeptin, pAdiponectin, and erythrocyte sedimentation rate) were lower in presence of cam deformity and cam impingement, but high-sensitivity C-reactive protein was not. Most associations depended largely on gender differences. CONCLUSION: Bone metabolism may be relevant in the pathogenesis of (superior) cam deformity and in the development of (superior) cam deformity into hip OA. Subjects with cam deformity and cam impingement surprisingly showed lower levels of inflammation markers and adipokines. Associations of cartilage turnover markers with cam deformity and cam impingement were less obvious.

Biochemical markers of joint tissue damage increase shortly after a joint bleed; an explorative human and canine in vivo study.

OBJECTIVE: Evaluation whether biomarkers of joint damage are sensitive to change shortly after a joint bleed in hemophilia patients and in a canine model of blood-induced joint damage. METHODS: Blood and urine samples were collected from 10 hemophilia patients after they reported a joint bleed: within 2 days, after 3-5 days, and 12-14 days. Additionally, 90 days after the bleed a blood and urine sample was taken and considered to represent baseline condition. Commercial serum and urine biomarker assays were performed: urinary C-terminal telopeptide of type II collagen (uCTX-II), serum cartilage oligomeric matrix protein (sCOMP), serum cartilage cleavage product C1,2C, and serum chondroitin sulfate 846 (sCS846). The same panel of biomarkers was explored in dogs (n = 7) after induction of a first joint bleed by intra-articular blood injections. Biosamples were collected at baseline, day 2, 1 and 2 weeks later. RESULTS: In hemophilia patients, levels of uCTX-II and sCS846 increased 5 days after joint bleeding when compared with baseline (+52%; P = 0.021 and +14%; P = 0.011, respectively). In dogs, uCTX-II increased statistically significant from day 2 to day 7 (from 75% to 155% of baseline; P = 0.018), and sCOMP from baseline to day 2 (+46%; P = 0.028). CONCLUSIONS: This study demonstrates that biochemical markers of joint tissue damage increase shortly after a single joint bleed, both in humans with established hemophilic arthropathy (HA) and in an animal model of joint damage upon a first joint bleed. Biomarkers might be useful in monitoring the impact of a joint bleed and in evaluation of treatment of such bleeds.

Systemic biochemical markers of joint metabolism and inflammation in relation to radiographic parameters and pain of the knee: data from CHECK, a cohort of early-osteoarthritis subjects.

OBJECTIVE: To investigate associations of biochemical markers of joint metabolism and inflammation with minimum joint space width (JSW) and osteophyte area (OP area) of knees showing no or doubtful radiographic osteoarthritis (OA) and to investigate whether these differed between painful and non-painful knees. DESIGN: Serum (s-) and urinary (u-) levels of the cartilage markers uCTX-II, sCOMP, sPIIANP, and sCS846, bone markers uCTX-I, uNTX-I, sPINP, and sOC, synovial markers sPIIINP and sHA, and inflammation markers hsCRP and erythrocyte sedimentation rate (ESR) were assessed in subjects from CHECK (Cohort Hip and Cohort Knee) demonstrating Kellgren and Lawrence grade ≤1 OA on knee radiographs. Minimum JSW and OP area of these knees were quantified in detail using Knee Images Digital Analysis (KIDA). RESULTS: uCTX-II levels showed negative associations with minimum JSW and positive associations with OP area. sCOMP and sHA levels showed positive associations with OP area, but not with minimum JSW. uCTX-I and uNTX-I levels showed negative associations with minimum JSW and OP area. Associations of biochemical marker levels with minimum JSW were similar between painful and non-painful knees, associations of uCTX-II, sCOMP, and sHA with OP area were only observed in painful knees. CONCLUSIONS: In these subjects with no or doubtful radiographic knee OA, uCTX-II might not only reflect articular cartilage degradation but also endochondral ossification in osteophytes. Furthermore, sCOMP and sHA relate to osteophytes, maybe because synovitis drives osteophyte development. High bone turnover may aggravate articular cartilage loss. Metabolic activity in osteophytes and synovial tissue, but not in articular cartilage may be related to knee pain.