Osteoarthritis endotype discovery via clustering of biochemical marker data.

OBJECTIVES: Osteoarthritis (OA) patient stratification is an important challenge to design tailored treatments and drive drug development. Biochemical markers reflecting joint tissue turnover were measured in the IMI-APPROACH cohort at baseline and analysed using a machine learning approach in order to study OA-dominant phenotypes driven by the endotype-related clusters and discover the driving features and their disease-context meaning. METHOD: Data quality assessment was performed to design appropriate data preprocessing techniques. The k-means clustering algorithm was used to find dominant subgroups of patients based on the biochemical markers data. Classification models were trained to predict cluster membership, and Explainable AI techniques were used to interpret these to reveal the driving factors behind each cluster and identify phenotypes. Statistical analysis was performed to compare differences between clusters with respect to other markers in the IMI-APPROACH cohort and the longitudinal disease progression. RESULTS: Three dominant endotypes were found, associated with three phenotypes: C1) low tissue turnover (low repair and articular cartilage/subchondral bone turnover), C2) structural damage (high bone formation/resorption, cartilage degradation) and C3) systemic inflammation (joint tissue degradation, inflammation, cartilage degradation). The method achieved consistent results in the FNIH/OAI cohort. C1 had the highest proportion of non-progressors. C2 was mostly linked to longitudinal structural progression, and C3 was linked to sustained or progressive pain. CONCLUSIONS: This work supports the existence of differential phenotypes in OA. The biomarker approach could potentially drive stratification for OA clinical trials and contribute to precision medicine strategies for OA progression in the future. TRIAL REGISTRATION NUMBER: NCT03883568.

Rubus idaeus extract improves symptoms in knee osteoarthritis patients: results from a phase II double-blind randomized controlled trial.

BACKGROUND: Osteoarthritis (OA) is the most frequent cause of disability in elderly people. In daily practice, the main objective of the physician is to reduce patient symptoms using treatments without adverse effects. However, the most prescribed treatment to manage OA symptoms remains nonsteroidal anti-inflammatory drugs which are associated with severe adverse effects. Therefore, we need a safe alternative to managing OA. One candidate is Rubus idaeus leaf extracts known to inhibit inflammatory responses. OBJECTIVE: This study aimed to evaluate the effects of a 12-weeks intervention with an ethanolic extract from Rubus idaeus leaf on symptoms of knee osteoarthritis. METHOD: The study was a randomized, double-blind, placebo-controlled, monocentric trial of 198 participants with femorotibial osteoarthritis. Participants were randomized equally to receive one daily during 3 months either 1 capsule of Rubus idaeus leaf extract 400 mg, 1 capsule of Rubus idaeus leaf extract 200 mg, or 1 capsule of placebo. The participants were assessed at baseline and after one and three months of treatment. The primary endpoint was an absolute change of the Western Ontario McMaster osteoarthritis index (WOMAC) pain subscale. The secondary endpoints were WOMAC global score, stiffness and function sub-scales, knee pain VAS score at walking, the Short Form (SF)-36, the Short Physical Performance Battery (SPPB), the 20-m walk test, and the International Physical Activity Questionnaire (IPAQ) and Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) responders rate. Statistical analyses were conducted on the intent-to-treat (ITT) population. RESULTS: In the Intention-to-treat population, WOMAC pain was not significantly modified by Rubus idaeus leaf extract compared to placebo. In contrast, Rubus idaeus leaf extract 400 mg after 12 weeks of treatment significantly reduced pain measured by the VAS. The mean pain decrease induced by Rubus ideaus leaf extract was over -7 mm which is clinically relevant and reached a clinically statistical difference compared to placebo with the highest dose. Rubus Ideaus was not significantly more efficient than the placebo on WOMAC global score, stiffness, and physical function subscores, IPAQ, SF-36, walking distance in treadmill test, SPPB, and evaluation of associated treatments needed to manage OA. CONCLUSION: Rubus idaeus leaf extract was well tolerated and effective to relieve pain in a patient with knee osteoarthritis. TRIAL REGISTRATION: NCT03703024  (11/10/2018).

Curcuma longa and Boswellia serrata extract combination for hand osteoarthritis: an open-label pre-post trial.

CONTEXT: Osteoarthritis (OA) of the hand is a common painful musculoskeletal disorder with no cure. There is a need for an efficient and safe treatment to relieve OA pain. OBJECTIVE: To investigate the effects of a Curcuma longa and Boswellia serrata food supplement in addition to standard care on hand pain. MATERIALS AND METHODS: This open-label, non-controlled, post-observational study was based on 232 patients suffering from hand pain with or without joint deformity. Patients received a medical prescription for a three-month treatment with a food supplement containing 89 mg of C. longa dry extract, 120 mg of B. serrata resin, and 1.8 µg vitamin D. Pain was evaluated on a 10-point visual analog scale (VAS). The number of painful hand joints, patient satisfaction, nonsteroidal anti-inflammatory drugs intake, and side effects were also recorded. RESULTS: Baseline pain intensity (regression coefficient ± SE: -0.19 ± 0.01, p < 0.0001) and the number of painful joints (regression coefficient ± SE: -0.022 ± 0.0029, p < 0.0001) decreased significantly throughout the 3 months treatment period. NSAIDs intake and topical drug application were significantly decreased by 64% (p < 0.0001) and 79% (p < 0.0001) after 12 weeks, respectively. Only 3/239 (1.3%) patients reported side effects probably related to the product. 80.3% were satisfied with the treatment and 75.5% wished to continue treatment. CONCLUSION: This is the first clinical trial showing that C. longa and B. serrata resin can relieve symptoms in patients with hand osteoarthritis. The study provides useful information for the design of a clinical trial including a broader population.

Serum NT/CT SIRT1 ratio reflects early osteoarthritis and chondrosenescence.

OBJECTIVE: Previous work has established that the deacetylase sirtuin-1 (SIRT1) is cleaved by cathepsin B in chondrocytes subjected to proinflammatory stress, yielding a stable but inactive N-terminal (NT) polypeptide (75SIRT1) and a C-terminal (CT) fragment. The present work examined if chondrocyte-derived NT-SIRT1 is detected in serum and may serve as an investigative and exploratory biomarker of osteoarthritis (OA). METHODS: We developed a novel ELISA assay to measure the ratio of NT to CT of SIRT1 in the serum of human individuals and mice subjected to post-traumatic OA (PTOA) or age-dependent OA (ADOA). We additionally monitored NT/CT SIRT1 in mice subject to ADOA/PTOA followed by senolytic clearance. Human chondrosenescent and non-senescent chondrocytes were exposed to cytokines and analysed for apoptosis and NT/CT SIRT1 ratio in conditioned medium. RESULTS: Wild-type mice with PTOA or ADOA of moderate severity exhibited increased serum NT/CT SIRT1 ratio. In contrast, this ratio remained low in cartilage-specific Sirt1 knockout mice despite similar or increased PTOA and ADOA severity. Local clearance of senescent chondrocytes from old mice with post-traumatic injury resulted in a lower NT/CT ratio and reduced OA severity. While primary chondrocytes exhibited NT/CT ratio increased in conditioned media after prolonged cytokine stimulation, this increase was not evident in cytokine-stimulated chondrosenescent cells. Finally, serum NT/CT ratio was elevated in humans with early-stage OA. CONCLUSIONS: Increased levels of serum NT/CT SIRT1 ratio correlated with moderate OA in both mice and humans, stemming at least in part from non-senescent chondrocyte apoptosis, possibly a result of prolonged inflammatory insult.

Molecular taxonomy of osteoarthritis for patient stratification, disease management and drug development: biochemical markers associated with emerging clinical phenotypes and molecular endotypes.

PURPOSE OF REVIEW: This review focuses on the molecular taxonomy of osteoarthritis from the perspective of molecular biomarkers. We discuss how wet biochemical markers may be used to understand disease pathogenesis and progression and define molecular endotypes of osteoarthritis and how these correspond to clinical phenotypes. RECENT FINDINGS: Emerging evidence suggests that osteoarthritis is a heterogeneous and multifaceted disease with multiple causes, molecular endotypes and corresponding clinical phenotypes. Biomarkers may be employed as tools for patient stratification in clinical trials, enhanced disease management in the primary care centres of the future and for directing more rational and targeted osteoarthritis drug development. Proximal molecular biomarkers (e.g synovial fluid) are more likely to distinguish between molecular endotypes because there is less interference from systemic sources of biomarker noise, including comorbidities. SUMMARY: In this review, we have focused on the molecular biomarkers of four distinct osteoarthritis subtypes including inflammatory, subchondral bone remodelling, metabolic syndrome and senescent age-related endotypes, which have corresponding phenotypes. Progress in the field of osteoarthritis endotype and phenotype research requires a better understanding of molecular biomarkers that may be used in conjunction with imaging, pain and functional assessments for the design of more effective, stratified and individualized osteoarthritis treatments.

Hyaluronan derivative HYMOVIS® increases cartilage volume and type ii collagen turnover in osteoarhritic knee: data from MOKHA study.

BACKGROUND: The objective of this pilot study was to identify biological, clinical or structural biomarkers of an intra-articular hyaluronic acid injection efficacy (HYMOVIS®) for the design of a larger placebo-controlled clinical trial studying the disease-modifying activity of this treatment. METHODS: Forty six patients with symptomatic knee Osteoarthritis (OA) were enrolled in this open-label, prospective, multicenter, pilot study. Patients received two treatment cycles of intra-articular injections (3 mL) of HYMOVIS® (8 mg/mL of hyaluronic acid hexadecylamide) at 6 months interval. Each treatment cycle involved two intra-articular injections 1 week apart. All patients had Magnetic Resonance Imaging (MRI) of the target knee at baseline and 1 year, and blood samples to assess joint biomarkers. The primary outcome was the change in type II collagen-specific biomarkers (Coll2-1, Coll2-1NO2 and CTX-II) after HYMOVIS® treatment versus baseline. Secondary endpoints included levels changes in aggrecan chondroitin sulfate 846 epitope (CS-846), Cartilage Oligomeric Matrix Protein (COMP), procollagen type II N-terminal propeptide (PIIANP), Matrix Metalloprotease (MMP)-3, Myeloperoxidase (MPO) and Interleukin (IL)-6 serum biomarkers, the ratio Coll2-1/PIIANP, CTX-II/PIIANP, variation of MRI cartilage volume, and Knee injury and Osteoarthritis Outcome Score (KOOS) index. RESULTS: Coll2-1 serum levels significantly increased overtime while Coll2-1NO2 levels were only increased at D360. Serum PIIANP levels also progressively and significantly enhanced with time. In contrast, other serum biomarker levels including CTX-II, CS-846, COMP, MMP-3, MPO or IL-6 did not change significantly overtime. Interestingly, the ratios Coll2-1/PIIANP and CTX-II/PIIANP decreased, indicating a decrease of cartilage catabolism. Compared to baseline value, MRI cartilage volume and thickness increased in lateral femoral and lateral trochlea compartments and not in medial compartment. These results, in addition to an improvement of T2 mapping score suggest a positive structural effect of the product. Interestingly, WORMS effusion score, an indicator of synovitis, significantly decreased. Finally, global KOOS score and subscales significantly increased overtime while pain at rest, walking pain and patients or investigators global assessment of disease activity decreased. The safety profile was favorable with a low incidence of injection-site pain. CONCLUSION: HYMOVIS®, a well-tolerated intra-articular treatment, significantly enhanced type II collagen turnover as suggested by the increase in Coll2-1 and PIIANP levels and cartilage volume observed by MRI in lateral knee compartment. Importantly, this study provides critical information for the design of a larger phase III clinical trial investigating Disease Modifying effect of HYMOVIS®. TRIAL REGISTRATION: http://www.isrctn.com/ISRCTN12227846 11/02/2015.

Altered Expression of MicroRNAs in Rheumatoid Arthritis.

Rheumatoid arthritis is one of the most common types of inflammatory joint diseases. Women, smokers, and people with positive family history are more susceptible to this disease. Diagnostic criteria include at least one swollen joint that has not been caused by other diseases. MicroRNAs are non-coding RNAs that are evolutionarily conserved and have a length of 18-25 nucleotides. MicroRNAs control gene expression at the post-transcriptional level via promoting mRNA degradation or translational repression. Recognition of alterations in microRNA status and their respective targets, may offer an opportunity to better identify the pathways that are involved in the etiopathogenesis of autoimmune diseases. It has been suggested that microRNAs may serve as potential biomarkers for both diagnosis and prognosis of autoimmune diseases. Here, we review the available evidence on the deregulations of microRNA expression in rheumatoid arthritis. More precisely, this review focuses on the microRNA involved in T cell regulation and gives perspectives on the use of this microRNA as biomarkers of diagnosis, prognosis, or intervention efficacy. J. Cell. Biochem. 119: 478-487, 2018. © 2017 Wiley Periodicals, Inc.

LEF1-mediated MMP13 gene expression is repressed by SIRT1 in human chondrocytes.

Reduced SIRT1 activity and levels during osteoarthritis (OA) promote gradual loss of cartilage. Loss of cartilage matrix is accompanied by an increase in matrix metalloproteinase (MMP) 13, partially because of enhanced LEF1 transcriptional activity. In this study, we assessed the role of SIRT1 in LEF1-mediated MMP13 gene expression in human OA chondrocytes. Results showed that MMP13 protein levels and enzymatic activity decreased significantly during SIRT1 overexpression or activation by resveratrol. Conversely, MMP13 gene expression was reduced in chondrocytes transfected with SIRT1 siRNA or treated with nicotinamide (NAM), a sirtuin inhibitor. Chondrocytes challenged with IL-1ß, a cytokine involved in OA pathogenesis, enhanced LEF1 protein levels and gene expression, resulting in increased MMP13 gene expression; however, overexpression of SIRT1 during IL-1ß challenge impeded LEF1 levels and MMP13 gene expression. Previous reports showed that LEF1 binds to the MMP13 promoter and transactivates its expression, but we observed that SIRT1 repressed LEF1 protein and mRNA expression, ultimately reducing LEF1 transcriptional activity, as judged by luciferase assay. Finally, mouse articular cartilage from Sirt1-/- presented increased LEF1 and MMP13 protein levels, similar to human OA cartilage. Thus, demonstrating for the first time that SIRT1 represses MMP13 in human OA chondrocytes, which appears to be mediated, at least in part, through repression of the transcription factor LEF1, a known modulator of MMP13 gene expression.-Elayyan, J., Lee, E.-J., Gabay, O., Smith, C. A., Qiq, O., Reich, E., Mobasheri, A., Henrotin, Y., Kimber, S. J., Dvir-Ginzberg, M. LEF1-mediated MMP13 gene expression is repressed by SIRT1 in human chondrocytes.

Natural Products for Promoting Joint Health and Managing Osteoarthritis.

PURPOSE OF REVIEW: Osteoarthritis, the most common joint disease, is associated with substantial medical costs, lost productivity, and reduced quality of life. However, available pharmaceutical treatments have limitations in terms of efficacy and long-term safety. RECENT FINDINGS: In vitro evidence suggests that some natural products may possess anti-inflammatory and anti-oxidative properties and may inhibit the release of key osteoarthritis-related cytokines. There is, therefore, ongoing interest in identifying natural products that safely promote joint health and treat osteoarthritis. Numerous plant extracts, including curcumin, Boswellia extract, and pycnogenol, have shown effect sizes (ES) for reducing pain and functional disability larger than those observed with analgesics and products such as glucosamine and chondroitin. The ES for methylsulfonylmethane and avocado/soybean unsaponifiables are also considered to be clinically relevant. Data from a small number of studies using natural products for treating osteoarthritis are promising but require confirmation in further well-designed clinical trials.

Evaluation of Differentiated Bone Cells Proliferation by Blue Shark Skin Collagen via Biochemical for Bone Tissue Engineering.

Collagen from a marine resource is believed to have more potential activity in bone tissue engineering and their bioactivity depends on biochemical and structural properties. Considering the above concept, pepsin soluble collagen (PSC) and acid soluble collagen (ASC) from blue shark (Prionace glauca) skin were extracted and its biochemical and osteogenic properties were investigated. The hydroxyproline content was higher in PSC than ASC and the purified collagens contained three distinct bands α1, α2, and ß dimer. The purity of collagen was confirmed by the RP-HPLC profile and the thermogravimetric data showed a two-step thermal degradation pattern. ASC had a sharp decline in viscosity at 20⁻30 °C. Scanning electron microscope (SEM) images revealed the fibrillar network structure of collagens. Proliferation rates of the differentiated mouse bone marrow-mesenchymal stem (dMBMS) and differentiated osteoblastic (dMC3T3E1) cells were increased in collagen treated groups rather than the controls and the effect was dose-dependent, which was further supported by higher osteogenic protein and mRNA expression in collagen treated bone cells. Among two collagens, PSC had significantly increased dMBMS cell proliferation and this was materialized through increasing RUNX2 and collagen-I expression in bone cells. Accordingly, the collagens from blue shark skin with excellent biochemical and osteogenic properties could be a suitable biomaterial for therapeutic application.

A randomized, double-blind, prospective, placebo-controlled study of the efficacy of a diet supplemented with curcuminoids extract, hydrolyzed collagen and green tea extract in owner's dogs with osteoarthritis.

BACKGROUND: We have previously demonstrated that a mixture of Curcuminoids extract, hydrolyzed COllagen and green Tea extract (CCOT) inhibited inflammatory and catabolic mediator's synthesis by bovine and human chondrocytes. A randomly allocated, double-blind, prospective, placebo-controlled study was performed to evaluate the efficacy of a diet containing this CCOT mixture on dogs with naturally occurring osteoarthritis (OA). Therefore, 42 owner's dogs with OA were randomly assigned to receive for 3 months an experimental diet (control) or the same diet supplemented with CCOT. RESULTS: Ground reaction forces did not show statistical differences between groups. After 3 months of feeding, there was a significant reduction of pain at manipulation in the CCOT group, but not in the control group. The evolution for pain at manipulation depended on the diet. The three other parameters evaluated by veterinary subjective assessment (lameness, pain at palpation and joint mobility) did not show statistical differences. Concerning owner subjective assessment, pain severity score worsened in the control group but remained stable in CCOT group. The evolution for pain severity depended on the diet. No statistical difference was found for pain interference, except for the ability to rise to standing from lying down, which was significantly improved in the CCOT compared to the control group. Serum OA biomarkers did not show statistical differences. CONCLUSIONS: Objective variables measured, such as ground reaction forces and OA biomarkers, did not show statistical differences. However, indicators of pain appeared reduced in dogs receiving CCOT mixture for 3 months. The difference of evolution between groups suggests that a greater number of dogs may be necessary to reach a stronger effect on other parameters.

Reduction of the Serum Levels of a Specific Biomarker of Cartilage Degradation (Coll2-1) by Hyaluronic Acid (KARTILAGE® CROSS) Compared to Placebo in Painful Knee Osteoarthritis Patients: the EPIKART Study, a Pilot Prospective Comparative Randomized Double Blind Trial.

BACKGROUND: Viscosupplementation is a symptomatic treatment of the knee osteoarthritis based on the intra-articular injection of hyaluronic acid (IAHA). Although many studies have investigated its effect on symptoms, few clinical studies have focused on its effects on biologicals markers of cartilage metabolism. In this study, we assessed the effect of an intra-articular injection of a reticulated hyaluronic acid compound on the level of a specific biomarker of type II collagen degradation. METHODS: Eighty one patients with symptomatic knee osteoarthritis were included in this randomized placebo controlled trial testing a reticulated hyaluronic acid (HA) with mannitol (KARTILAGE® CROSS, 16 mg/ml, one single injection of 2.2 mL; IAHA) versus saline solution. Primary outcome was the percentage of patients with a reduction of at least 10 nmol/l of serum Coll2-1 between baseline and day 90 (D90, 3 months after injection). Secondary outcomes concerned clinical evaluation and tolerance to the study product. RESULTS: A significant effect of IAHA was revealed by the sensitivity analysis of the decrease in cartilage marker. In the intention-to-treat population, the percentage of patients showing a decrease in the levels of serum Coll2-1 between inclusion and D90 showed was higher in HA (56.8%) than in placebo group (28.6%; P = 0.01). The same significant difference was observed between groups in the per protocol population (57.1% vs 29.0%; P = 0.02) corresponding to all patients having received the intra-articular injection (IA), being evaluated for the primary outcome on D-10 and D90, and with no major defined deviation. No significant differences between groups were observed on the changes in function (Lequesne index) or pain and on the number of adverse events. CONCLUSIONS: This is the first randomized double-blind placebo controlled trial showing that IA injection of reticulated HA with mannitol in knee osteoarthritis patients can reduce the serum levels of Coll2-1, a marker specific of type II collagen degradation. This finding suggests that IAHA may have a beneficial effect on cartilage degradation and that Coll2-1 could be used for the assessment of a single intra-articular treatment in clinical trials. TRIAL REGISTRATION: NCT02951585 ; clinicaltrial.gov. Retrospectively registered on October 28, 2016.

Combined chondroitin sulfate and glucosamine for painful knee osteoarthritis: a multicentre, randomised, double-blind, non-inferiority trial versus celecoxib.

OBJECTIVES: To compare the efficacy and safety of chondroitin sulfate plus glucosamine hydrochloride (CS+GH) versus celecoxib in patients with knee osteoarthritis and severe pain. METHODS: Double-blind Multicentre Osteoarthritis interVEntion trial with SYSADOA (MOVES) conducted in France, Germany, Poland and Spain evaluating treatment with CS+GH versus celecoxib in 606 patients with Kellgren and Lawrence grades 2-3 knee osteoarthritis and moderate-to-severe pain (Western Ontario and McMaster osteoarthritis index (WOMAC) score ≥301; 0-500 scale). Patients were randomised to receive 400 mg CS plus 500 mg GH three times a day or 200 mg celecoxib every day for 6 months. The primary outcome was the mean decrease in WOMAC pain from baseline to 6 months. Secondary outcomes included WOMAC function and stiffness, visual analogue scale for pain, presence of joint swelling/effusion, rescue medication consumption, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria and EuroQoL-5D. RESULTS: The adjusted mean change (95% CI) in WOMAC pain was -185.7 (-200.3 to -171.1) (50.1% decrease) with CS+GH and -186.8 (-201.7 to -171.9) (50.2% decrease) with celecoxib, meeting the non-inferiority margin of -40: -1.11 (-22.0 to 19.8; p=0.92). All sensitivity analyses were consistent with that result. At 6 months, 79.7% of patients in the combination group and 79.2% in the celecoxib group fulfilled OMERACT-OARSI criteria. Both groups elicited a reduction >50% in the presence of joint swelling; a similar reduction was seen for effusion. No differences were observed for the other secondary outcomes. Adverse events were low and similarly distributed between groups. CONCLUSIONS: CS+GH has comparable efficacy to celecoxib in reducing pain, stiffness, functional limitation and joint swelling/effusion after 6 months in patients with painful knee osteoarthritis, with a good safety profile. TRIAL REGISTRATION NUMBER: NCT01425853.

Analgesic Efficacy and Safety of Curcuminoids in Clinical Practice: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Curcuminoids are natural products with potent anti-inflammatory and antioxidant properties. There have been a number of reports on the analgesic effects of curcuminoids in clinical trials, yet data have not been fully conclusive. OBJECTIVES: To provide the highest level of evidence on the efficacy of curcuminoids in patients with painful conditions through meta-analysis of data from randomized controlled trials (RCTs). METHODS: A systematic review and meta-analysis was conducted using data reported by RCTs. The primary efficacy measure was pain intensity or algofunctional status. Treatment effect was summarized with standardized mean difference (SMD) calculated from differences in means of pain measures between treatment and control groups using a random-effects model. RESULTS: A total of eight RCTs met our inclusion criteria that included 606 randomized patients. Curcuminoids were found to significantly reduce pain (SMD: -0.57, 95% CI: -1.11 to -0.03, P = 0.04). This pain-relieving effect was found to be independent of administered dose and duration of treatment with curcuminoids, and was free from publication bias. Curcuminoids were safe and well tolerated in all evaluated RCTs. CONCLUSION: Curcuminoids supplements may be a safe and effective strategy to improve pain severity, by warranting further rigorously conducted studies to define the long-term efficacy and safety.

Effect of chondroitin sulfate on soluble biomarkers of osteoarthritis: a method to analyze and interpret the results from an open-label trial in unilateral knee osteoarthritis patients.

BACKGROUND: The aim of this study was to investigate the effects of chondroitin sulfate (CS) on the serum levels of Coll2-1 in patients with knee OA. METHODS: Seventy two patients with unilateral symptomatic knee OA were involved in a post-authorization open-label study evaluating CS (800 mg/day). The primary outcome was the % relative change in serum Coll2-1 (sColl2-1). The secondary outcomes were the evaluation of pain (VAS) and function (Lequesne's Index). Responders and non-responders were classified according to OMERACT-OARSI recommendations. Finally, an original cut-off method was applied to categorize patients and interpret individual variations in serum levels of Coll2-1. RESULTS: Patients showed no difference in the sColl2-1 levels at baseline. When considering responders and non-responders from the ITT population, a significant difference was found for Coll2-1 at 3 months (p = 0.030) and 6 months (p = 0.038). A decrease in pain (VAS) and an improvement in function (LI) were recorded throughout the visits (p < 0.01). Considering an intra-batch cut-off of 21 %, CS decreased Coll2-1 serum levels between baseline and 1-month visit compared to the value of Coll2-1 before treatment (screening visit) which can be interpreted as a drastic reduction of the proportion of patients with an increase of Coll2-1 over 21 % (reduction from 13 to 3 %). It also consisted in a more important proportion of patients with a decrease in Coll2-1 (from 5 to 10 %). CONCLUSION: This study proposes a new approach for the analysis and the interpretation of the individual variation in biomarker levels and introduces the notion of metabolic responders. TRIAL REGISTRATION: ID ISRCTN63795830 . The trial was retrospectively registered on 2 October, 2015.

Biomarkers of (osteo)arthritis.

Arthritic diseases are a major cause of disability and morbidity, and cause an enormous burden for health and social care systems globally. Osteoarthritis (OA) is the most common form of arthritis. The key risk factors for the development of OA are age, obesity, joint trauma or instability. Metabolic and endocrine diseases can also contribute to the pathogenesis of OA. There is accumulating evidence to suggest that OA is a whole-organ disease that is influenced by systemic mediators, inflammaging, innate immunity and the low-grade inflammation induced by metabolic syndrome. Although all joint tissues are implicated in disease progression in OA, articular cartilage has received the most attention in the context of aging, injury and disease. There is increasing emphasis on the early detection of OA as it has the capacity to target and treat the disease more effectively. Indeed it has been suggested that this is the era of "personalized prevention" for OA. However, the development of strategies for the prevention of OA require new and sensitive biomarker tools that can detect the disease in its molecular and pre-radiographic stage, before structural and functional alterations in cartilage integrity have occurred. There is also evidence to support a role for biomarkers in OA drug discovery, specifically the development of disease modifying osteoarthritis drugs. This Special Issue of Biomarkers is dedicated to recent progress in the field of OA biomarkers. The papers in this Special Issue review the current state-of-the-art and discuss the utility of OA biomarkers as diagnostic and prognostic tools.

Soluble biomarkers development in osteoarthritis: from discovery to personalized medicine.

CONTEXT: Specific soluble biomarkers could be a precious tool for diagnosis, prognosis and personalized management of osteoarthritic (OA) patients. OBJECTIVE: To describe the path of soluble biomarker development from discovery to clinical qualification and regulatory adoption toward OA-related biomarker qualification. METHODS AND RESULTS: This review summarizes current guidance on the use of biomarkers in OA in clinical trials and their utility at five stages, including preclinical development and phase 1 to phase 4 trials. It also presents all the available regulatory requirements. CONCLUSIONS: The path through the adoption of a specific soluble biomarker for OA is steep but is worth the challenge due to the benefit that it can provide.

Decrease of a specific biomarker of collagen degradation in osteoarthritis, Coll2-1, by treatment with highly bioavailable curcumin during an exploratory clinical trial.

BACKGROUND: The management of osteoarthritis (OA) remains a challenge. There is a need not only for safe and efficient treatments but also for accurate and reliable biomarkers that would help diagnosis and monitoring both disease activity and treatment efficacy. Curcumin is basically a spice that is known for its anti-inflammatory properties. In vitro studies suggest that curcumin could be beneficial for cartilage in OA. The aim of this exploratory, non-controlled clinical trial was to evaluate the effects of bio-optimized curcumin in knee OA patients on the serum levels of specific biomarkers of OA and on the evaluation of pain. METHODS: Twenty two patients with knee OA were asked to take 2x3 caps/day of bio-optimized curcumin (Flexofytol®) for 3 months. They were monitored after 7, 14, 28 and 84 days of treatment. Pain over the last 24 hours and global assessment of disease activity by the patient were evaluated using a visual analog scale (100 mm). The serum levels of Coll-2-1, Coll-2-1NO2, Fib3-1, Fib3-2, CRP, CTX-II and MPO were determined before and after 14 and 84 days of treatment. RESULTS: The treatment with curcumin was globally well tolerated. It significantly reduced the serum level of Coll2-1 (p<0.002) and tended to decrease CRP. No other significant difference was observed with the other biomarkers. In addition, curcumin significantly reduced the global assessment of disease activity by the patient. CONCLUSION: This study highlighted the potential effect of curcumin in knee OA patient. This effect was reflected by the variation of a cartilage specific biomarker, Coll2-1 that was rapidly affected by the treatment. These results are encouraging for the qualification of Coll2-1 as a biomarker for the evaluation of curcumin in OA treatment. TRIAL REGISTRATION: NCT01909037 at clinicaltrials.gov.

The Impact of Weight-bearing Exercise, Non-Weight-bearing Exercise, and Cardiovascular Stress on Biochemical Markers of Cartilage Turnover in Patients With Mild to Moderate Knee Osteoarthritis: A Sequential, Cross-Over, Clinical Study.

OBJECTIVE: To investigate how running, cycling, and sedentary cardiovascular stress impact biomarkers of cartilage turnover acutely in subjects with knee osteoarthritis (OA). DESIGN: This was a sequential, cross-over, clinical study. Forty subjects with primary knee OA underwent moderate-to-high-intensity cycling, running, and adrenaline infusion on separate days. Blood was sampled before, during, and at 6-time points after intervention. On a control day, similar samples were taken. Biomarkers of type II collagen degradation (C2M, T2CM, Coll2-1, Coll2-1NO2), formation (PRO-C2), and aggrecan degradation (ARGS) were measured. RESULTS: Mean age was 60.4 years, 40% were male, 45% had cumulated Kellgren-Lawrence (KL)-grade (Right + Left knee) of 2 to 3 and 55% had 4 to 6. Analyzing overall changes, area under the curve was significantly lower compared with resting values for ARGS and C2M after cycling and for ARGS after running. Considering individual time points, peak changes in biomarker levels showed reduction in C2M shortly following cycling (T20min = -12.3%, 95% confidence interval [CI]: -19.3% to -5.2%). PRO-C2 increased during cycling (T10min = 14.0%, 95% CI = 4.1% to 23.8%) and running (T20min = 16.5%, 95% CI = 4.3% to 28.6%). T2CM decreased after cycling (T50min = -19.9%, 95% CI = -29.2% to -10.6%), running (T50min = -22.8%, 95% CI = -32.1% to -13.5%), and infusion of adrenaline (peak, T50min = -9.8%, 95% CI = -20.0% to 0.4%). A latent increase was seen in Coll2-1 240 minutes after running (T260min = 21.7%, 95% CI = -1.6% to 45.1%). CONCLUSION: Exercise had an impact on cartilage markers, but it did not suggest any detrimental effect on cartilage. Changes following adrenaline infusion suggest a sympathomimetic influence on the serological composition of biomarkers.

The Osteoblast Transcriptome in Developing Zebrafish Reveals Key Roles for Extracellular Matrix Proteins Col10a1a and Fbln1 in Skeletal Development and Homeostasis.

Zebrafish are now widely used to study skeletal development and bone-related diseases. To that end, understanding osteoblast differentiation and function, the expression of essential transcription factors, signaling molecules, and extracellular matrix proteins is crucial. We isolated Sp7-expressing osteoblasts from 4-day-old larvae using a fluorescent reporter. We identified two distinct subpopulations and characterized their specific transcriptome as well as their structural, regulatory, and signaling profile. Based on their differential expression in these subpopulations, we generated mutants for the extracellular matrix protein genes col10a1a and fbln1 to study their functions. The col10a1a-/- mutant larvae display reduced chondrocranium size and decreased bone mineralization, while in adults a reduced vertebral thickness and tissue mineral density, and fusion of the caudal fin vertebrae were observed. In contrast, fbln1-/- mutants showed an increased mineralization of cranial elements and a reduced ceratohyal angle in larvae, while in adults a significantly increased vertebral centra thickness, length, volume, surface area, and tissue mineral density was observed. In addition, absence of the opercle specifically on the right side was observed. Transcriptomic analysis reveals up-regulation of genes involved in collagen biosynthesis and down-regulation of Fgf8 signaling in fbln1-/- mutants. Taken together, our results highlight the importance of bone extracellular matrix protein genes col10a1a and fbln1 in skeletal development and homeostasis.