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The purpose was to investigate relationships of cumulative load and cartilage turnover biomarkers with 2-year changes in cartilage in knee osteoarthritis. From participants with Kellgren-Lawrence (KL) grades of 1 to 3, cartilage thickness and transverse relaxation time (T2) were computed from 24-month (baseline) and 48-month magnetic resonance images. Cumulative load was the interaction term of the Physical Activity Scale for the Elderly (PASE) and body mass index (BMI). Serum cartilage oligomeric matrix protein (COMP) and the nitrated form of type II collagen (Coll2-1 NO2) were collected at baseline. Multiple regressions (adjusted for baseline age, KL grade, cartilage measures, pain, comorbidity) evaluated the relationships of cumulative load and biomarkers with 2-year changes. In 406 participants (63.7 (8.7) years), interactions of biomarkers with cumulative load weakly predicted 2-year cartilage changes: (i) COMP × cumulative load explained medial tibia thickness change (R 2 increased 0.062 to 0.087, p < 0.001); (ii) Coll2-1 NO2 × cumulative load explained central medial femoral T2 change (R 2 increased 0.177 to 0.210, p < 0.001); and (iii) Coll2-1 NO2 × cumulative load explained lateral tibia T2 change (R 2 increased 0.166 to 0.188, p < 0.001). Moderate COMP or Coll2-1 NO2 at baseline appeared protective. High COMP or Coll2-1 NO2, particularly with high BMI and low PASE, associated with worsening cartilage. Moderate serum concentrations of cartilage turnover biomarkers, at high and low physical activity, associated with maintained cartilage outcomes over 2 years. In conclusion, high concentrations of cartilage turnover biomarkers, particularly with high BMI and low physical activity, associated with knee cartilage thinning and increasing T2 over 2 years. Key Points • Higher quality cartilage may be better able to tolerate a larger cumulative load than poor quality cartilage. • Among participants enrolled in the Osteoarthritis Initiative Biomarkers Consortium Project, a representation of cumulative load exposure and its interaction with cartilage turnover biomarkers were weakly related with 2-year change in knee cartilage. • These findings suggest that cartilage turnover is a factor that modifies the relationship between loading exposure and cartilage loss in knee OA., (© 2024. The Author(s), under exclusive licence to International League of Associations for Rheumatology (ILAR).)

Background: Work-related musculoskeletal disorders are common health problems in brick manufacturers, where mechanical load leads to degenerative joint diseases. Collagen type II metabolite (C2C) is a small peptide excreted in urine, and its serum concentration can directly reflect articular cartilage decomposition., Objective: Early detection of musculoskeletal disorders among brick workers, using serum C2C as a biomarker of cartilage damage., Methods: This study involved 88 male brick workers in Arab Abu Saed matched to 88 age- and sex-matched controls. Full history taking, pain assessment using the Standardized Nordic Questionnaire, and complete clinical examination were done for both groups. Serum C2C was measured using a competitive immunoassay method., Results: Brick workers involved in the study were of a mean age 30.66 ± 7.90 years and mean work duration 14.80 ± 7.89 years, matched to 88 controls. The majority of the participants (77.3%) were of normal body mass index. An increase in pain/discomfort was found among the exposed group. Serum C2C had an increased mean among the exposed group compared with the control. Pearson correlation between serum C2C level, body mass index, age, and years of employment showed no correlation., Conclusions: Musculoskeletal disorders are prevalent among brick workers who adopt specific awkward postures, unhealthy working conditions, and nonexistent safety procedures, for prolonged periods. Detection of serum C2C level can be used as a predictive biomarker for the early detection of musculoskeletal disorders among brick workers., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Osteoarthritis (OA) is characterized by the gradual loss of cartilage. Sprifermin, a recombinant FGF18, is being developed as a cartilage anabolic drug. PRO-C2 is a serum marker of type II collagen formation and low levels have been shown to be prognostic of radiographic progression. The aim of the study was to investigate whether the patient groups with either high or low PRO-C2 levels responded differently to sprifermin., Design: PRO-C2 was measured in synovial fluid (SF) (n = 59) and serum samples (n = 225) from participants of the FORWARD study, a 2-year phase IIb clinical trial testing the efficacy of intra-articular (IA) sprifermin over placebo. The difference between sprifermin and placebo in respect to in change cartilage thickness (measured by quantitative (q) MRI) was analyzed in groups with either high or low (3 rd vs 1 st -2 nd tertiles) baseline serum PRO-C2 levels., Results: SF levels of PRO-C2 increased over time in response to sprifermin, but not to placebo. In the placebo arm, significantly (p = 0.005) more cartilage was lost in the low vs high PRO-C2 group over the 2-year period. The contrast between sprifermin and placebo was significant (p < 0.001), ranging from 0.104 mm at week 26 to 0.229 mm at week 104 in the low PRO-C2 group. This result was not significant in the high PRO-C2 group ranging from -0.034 to 0.142., Conclusions: Patients with low serum PRO-C2 levels lost more cartilage thickness over time and grew more cartilage in response to sprifermin vs a placebo when compared to patients with high PRO-C2 levels., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: To assess the cross-sectional association between serum levels of Coll2-1 and Coll2-1NO2, two cartilage degradation biomarkers; the burden of magnetic resonance imaging (MRI) features and clinical outcomes; and to evaluate the predictive value of these biomarkers on progression., Design: A total of 121 subjects with knee osteoarthritis (OA) were followed during 1 year with pain, function, and MRI assessment (PRODIGE study). Type II collagen-specific biomarker Coll2-1 and its nitrated form Coll2-1NO2 were directly measured in serum using immunoassays at baseline and after 3-, 6-, and 12-month follow-up., Results: Serum Coll2-1 and Coll2-1NO2 were correlated with several baseline knee features quantified with Whole-Organ Magnetic Resonance Imaging Score (WORMS). Coll2-1 was significantly correlated with periarticular cysts/bursitis (ρ = 0.29, P < 0.01), subarticular bone attrition (ρ = 0.25, P = 0.01), subarticular cysts (ρ = 0.24, P = 0.02), and articular cartilage integrity (ρ = 0.23, P = 0.03) WORMS subscores for the whole joint as well as with the medial femorotibial joint sum score (ρ = 0.26, P = 0.01) and medial femorotibial joint cartilage (ρ = 0.23, P = 0.02). Coll2-1NO2 correlated with WORMS total score (ρ = 0.23, P = 0.02), WORMS scores in the patellofemoral (ρ = 0.23, P = 0.02) and medial femorotibial compartments (ρ = 0.21, P = 0.03), with osteophytes scores (ρ = 0.27, P < 0.01), subarticular cysts (ρ = 0.24, P = 0.019), and intraarticular loose bodies (ρ = 0.27, P = 0.007). Baseline Coll2-1NO2 was higher in subjects with a pain worsening (426.4 pg/mL [278.04-566.95]) as compared to non-progressors (306.84 pg/mL [200.37-427.84]) over 1 year (AUC = 0.655, P = 0.015)., Conclusion: Serum cartilage biomarkers Coll2-1 and Coll2-1NO2 are associated with several knee OA features quantified with WORMS. Our study also shows that the baseline value of Coll2-1NO2 is positively associated with pain worsening.

Treatment of knee osteoarthritis (OA) remains a challenging concern. Preclinical studies provided accumulating evidence on resveratrol efficacy in ameliorating degenerative articular damage. The present study was conducted to evaluate the effects of resveratrol as monotherapy on the serum level of type II collagen (Coll 2-1) and aggrecan in patients with knee osteoarthritis. The study was an open-labeled noncontrolled clinical trial. Resveratrol 500 mg/day in a single oral dose was given to the patients with knee osteoarthritis for 90 days. The serum levels of Coll-2-1, aggrecan, and biomarkers of inflammation were measured pre- and posttreatment. Hematological profiles and both hepatic and renal function markers were investigated at the baseline and at the end of the treatment for evaluating the tolerability and safety of resveratrol. Visual Analog Scale (VAS) for pain and Knee injury and Osteoarthritis Outcome Score (KOOS) for disease activity were clinically assessed monthly. Administration of 500 mg resveratrol for three months led to a nonsignificant decrease in the serum level of Coll 2-1 while a significant increase in aggrecan serum level. Resveratrol significantly improves pain score measured by VAS and KOOS after 30 days. Improvements in patients' activity and functional status were also evident at day 30 and kept on for three months which was reflected by KOOS subscale scores and with a significant improvement in all KOOS areas. In conclusion, oral administration of resveratrol as a monotherapy provides a remarkable improvement in the clinical status of the patients but has no significant effect on serum levels of Coll 2-1., Competing Interests: The author reports no conflicts of interest in this work., (Copyright © 2021 Bushra Hassan Marouf.)

Background: Diagnosis of intervertebral disc degeneration (IVDD) is challenging at the early stage. The cartilage oligomeric matrix protein (COMP) and extracellular matrix degradation products of C-telopeptide of type II collagen (CTX-II) serve as markers for the serological diagnosis of IVDD. Oxidative stress might cause IVDD and matrix degeneration., Methods: A total of 128 male adult Sprague-Dawley (SD) rats were randomly and equally assigned to the experimental and control groups. The experimental group was used to construct IVDD models by acupuncture, while the control group underwent sham operation. The animals were executed every week for 8 weeks after intervertebral disc acupuncture, and serum samples were collected for the estimation of CTX-II and COMP concentrations by enzyme-linked immunosorbent assay (ELISA). Also, the histological changes and caudal magnetic resonance imaging (MRI) changes were examined in the intervertebral disc., Results: IVDD in rats worsened with prolonged follow-up after acupuncture. At all the time points, the experimental group showed altered histological and caudal vertebra MRI signals, and serum CTX-II and COMP concentrations were significantly greater than those of the control group. These levels increase with the process of IVDD., Conclusion: Serum CTX-II and COMP estimation is a reliable method to diagnose IVDD, and their concentrations show a positive correlation with the process of IVDD., Competing Interests: The authors declare that they have no conflicts of interest., (Copyright © 2021 Dong-Duo Qi et al.)

Objective: To investigate acute changes in biochemical markers of cartilage turnover in response to moderate intensity exercise with and without joint impact in humans with knee osteoarthritis., Design: We conducted a randomized, cross-over, exploratory clinical study. Twenty subjects with knee osteoarthritis (OA) were randomized, of which twenty completed 30 min of cycling and 15 completed 30 min of running on days 1 week apart. Fasting blood samples were taken before, immediately after and 1, 2, 3, and 24 h after activity was initiated. Midstream spot urine was sampled before and after activity. Serum samples were analyzed for concentrations of fragment of type II collagen degradation, C2M, fragment of type VI collagen degradation, C6M, cartilage oligomeric matrix protein, COMP, marker of type II collagen formation, PRO-C2, and urine for marker of crosslinked type II collagen degradation, CTX-II. To establish a reference, all subjects had similar samples taken during rest on a separate day. Data was analyzed in a restricted maximum likelihood based random effects linear mixed model., Results: C2M trended to increase after cycling compared running (13.49%, 95%CI: -0.36-27.34%) and resting (12.88%, 95%CI: 0.2-25.6%) and the type II collagen formation/degradation ratio switched towards degradation after cycling, but not running. C6M trended to decrease after cycling (-8.1%, 95%CI: -14.8 to -1.4%) and running (-6.8%, 95%CI: -14.16-0.55%)., Conclusion: In persons with knee OA moderate intensity exercise without joint impact may induce acute changes in circulating levels of biochemical markers reflecting type II and VI collagen degradation., (Copyright © 2021 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Background: Osteoarthritis (OA) is a disease with multiple endotypes. A hallmark of OA is loss of cartilage; however, it is evident that the rate of cartilage loss differs among patients, which may partly be attributed to differential capacity for cartilage repair. We hypothesize that a low cartilage repair endotype exists and that such endotypes are more likely to progress radiographically. The aim of this study is to examine the associations of level of cartilage formation with OA severity and radiographic OA progression. We used the blood-based marker PRO-C2, reflecting type II collagen formation, to assess levels of cartilage formation., Materials and Methods: The type II collagen propeptide PRO-C2 was measured in the serum/plasma of knee OA subjects from New York University (NYU, n = 106) and a subcohort of the phase III oral salmon calcitonin (sCT) trial SMC021-2301 (SMC, n = 147). Risk of radiographic medial joint space narrowing (JSN) over 24 months was compared between quartiles (very low, low, moderate, and high) of PRO-C2. Associations were adjusted for age, gender, BMI, race, baseline pain levels, and baseline joint space width., Results: In both the NYU and SMC cohorts, subjects with low PRO-C2 levels had greater JSN compared with subjects with high PRO-C2. Mean difference in JSN between subjects with very low and high levels of PRO-C2 was 0.65 mm (p = 0.002), corresponding to a 3.4 (1.4-8.6)-fold higher risk of progression. There was no significant effect of sCT treatment, compared with placebo, on JSN over 2 years before stratification based on baseline PRO-C2. However, there were proportionately fewer progressors in the sCT arm of the very low/low PRO-C2 group compared with the moderate/high group (Chi squared = 6.5, p = 0.011)., Conclusion: Serum/plasma level of type II collagen formation, PRO-C2, may be an objective indicator of a low cartilage repair endotype, displaying radiographic progression and superior response to a proanabolic drug., Level of Evidence: Level III post hoc exploratory analysis of one longitudinal cohort and a sub-study from one phase III clinical trial.

Musculoskeletal changes are the most common clinical manifestation of brucellosis. The main objective of this study was to provide a better understanding of this disease, while also attempting to identify potential markers that can identify the early stage musculoskeletal changes associated with human brucellosis. In this case-control study, 41 male early-stage brucellosis patients (within 6 months of diagnosis) who had not received drug therapy and 44 matched controls were examined. Venous blood samples were collected and serum pyridinoline (PYD), type II collagen cleavage neoepitope (C2C) and osteocalcin (OC) levels were quantified using an enzyme-linked immunosorbent assay (ELISA). In the brucellosis group, the median serum levels of PYD (278.53 µg/L), C2C (82.23 µg/L) and OC (8.41 µg/L) were significantly elevated relative to the control group (Z = 5.686, 3.997, 3.579; P = 0.000). Serum PYD, C2C, and OC levels were increased in early-stage male brucellosis patients, and these factors appear to have promise as potential indicator biomarkers that can reflect the osteoarticular changes that occur in the early stage of human brucellosis.

Osteoarthritis (OA) is the most common chronic degenerative joint disease which causes substantial joint pain, deformity and loss of activities of daily living. Currently, there are over 500 million OA cases worldwide, and there is an urgent need to identify biomarkers for early detection, and monitoring disease progression in patients without obvious radiographic damage to the joint. We have used regression modelling to describe the association of 19 of the currently available biomarkers (predictors) with key radiographic and clinical features of OA (outcomes) in one of the largest and best characterised OA cohort (NIH Osteoarthritis Initiative). We demonstrate that of the 19 currently available biomarkers only 4 (serum Coll2-1 NO2, CS846, COMP and urinary CTXII) were consistently associated with established radiographic and/or clinical features of OA. These biomarkers are independent of one another and provide additional predictive power over, and above established predictors of OA such as age, gender, BMI and race. We also show that that urinary CTXII had the strongest and consistent associations with clinical symptoms of OA as well as radiographic evidence of joint damage. Accordingly, urinary CTXII may aid in early diagnosis of OA in symptomatic patients without radiographic evidence of OA.

Objective: To analyze the correlation between the Kellgren-Lawrence (K-L) score of knee osteoarthritis (KOA) patients with different degrees and their urine concentration of C-terminal telopeptide of collagen type II (CTX-II) and interleukin-1β (IL-1β), and to further evaluate the diagnostic value of CTX-II and IL-1β during the pathological process by producing an experimental osteoarthritis (OA) model in rabbits., Methods: From 1 January 2017 to 31 December 2018, a total of 34 subjects (7 mild, 9 moderate, 9 severe arthritis patients, and 9 healthy individuals) comprising 16 men and 18 women were included in this study. Patients were diagnosed according to the American College of Rheumatology (ACR) criteria. The urine of all subjects was collected to detect the concentration of CTX-II and IL-1β. The rabbits in the KOA group were subjected to protease (control group with saline) injection into the articular cavity of their right knees and immobilization with gypsum. We used radiological and histological examination to identify the KOA model. ELISA was applied to investigate the concentrations of CTX-II and IL-1β in urine and serum, and Spearman's rank correlation analysis was used to analyze the correlation., Results: There was no significant difference in the mean ages and body mass index (BMI) between groups. The mean ages of mild, moderate, and severe arthritis patients and healthy individuals were 54.29 ± 5.76, 58.44 ± 6.44, 59.89 ± 6.75, and 56.67 ± 4.18 years, respectively. The mean BMI of mild, moderate, and severe arthritis patients and healthy individuals were 23.59 ± 1.56, 23.57 ± 2.06, 24.46 ± 1.64, and 23.42 ± 1.35 kg/m 2 , respectively. The Kellgren-Lawrence (K-L) score was higher with the aggravation of KOA. The K-L scores of mild, moderate, and severe KOA patients were 1.14 ± 0.38, 2.56 ± 0.53, and 3.63 ± 0.52, respectively. The KOA symptoms of patients became more severe, with not only increased K-L scores but also elevated concentrations of CTX-II and IL-1β. Moreover, there was a positive correlation between CTX-II and IL-1β of all subjects (r = 0.974, P < 0.001), between K-L score and urine concentration of CTX-II (r = 0.900, P < 0.001), and between K-L score and IL-1β (r = 0.813, P < 0.001) of all subjects. Both were significantly increased in KOA group rabbits at all time points after surgery. The serum concentration of CTX-II and IL-1β was elevated as early as in the 2nd week (3.69 and 4.25 times) and reached a peak (5.41 and 7.23 times) in the 4th week after surgery. Then, until 12 weeks after surgery, the CTX-II and IL-1β concentrations in the KOA group were slightly reduced and remained around 4.5 and 6.3 times that in the control group. Moreover, there was a positive correlation between the serum concentration of IL-1β and CTX-II (r = 0.967, P < 0.001)., Conclusion: CTX-II and IL-1β, which were significantly increased during the process of KOA, can be used as biomolecular markers to provide guidelines for early diagnosis and treatment of KOA., (© 2019 The Authors. Orthopaedic Surgery published by Chinese Orthopaedic Association and John Wiley & Sons Australia, Ltd.)

Introduction : Osteoarthritis (OA) is the most common form of arthritis. However, there are no structure or disease-modifying OA drugs (DMOADs). Introducing personalized healthcare to patients and health-care practitioners is a high priority for the management of arthritic and musculoskeletal diseases. However, there are no biomarker tools that can be used for patient stratification, disease management, and drug development. Biomarkers are capable of diagnosing and prognosing some arthritic and musculoskeletal diseases. Cartilage-based biomarkers have the potential to be used in this context to guide the precision treatment of OA. Areas covered : The aim of this review is to focus on the pre-clinical and clinical utility of the Coll2-1 and Coll2-1NO2 biomarkers as unique cartilage-based biomarkers that can guide the development of new treatments for OA. This expert report will begin with a background to collagens and their important biomechanical roles in the musculoskeletal system, but particularly cartilage, before exploring the data and scientific evidence to support the utility of Coll2-1 and Coll2-1NO2 as unique biomarkers. Expert opinion : This review summarises the authors' expert view on the pre-clinical and clinical utility of the Coll2-1 and Coll2-1NO2 biomarkers and their potential for use as drug development tools.

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.

Background: The accumulation of cartilage breakdown products in body fluids has been extensively investigated to assess the accuracy of molecular biomarkers from a diagnostic, prognostic, and therapeutic perspective. Nevertheless, to the authors' knowledge, there is a lack of information about spontaneous models of hip osteoarthritis and the differentiating ability of collagen, noncollagen, and inflammatory biomarkers., Objectives: We aimed to assess the accuracy of four plasma biomarkers that could differentiate between healthy dogs and dogs with hip dysplasia., Methods: Twenty-four dogs were used in this institutionally approved study (12 in the mild to severe hip dysplasia group; 12 in the control group). Plasma concentrations of biomarkers were compared. The ability of each marker to differentiate control from diseased dogs was assessed using an independent t-test, logistic regression, and receiving operating characteristics (ROC) analysis., Results: Three biomarkers were significantly different between the two groups. The collagen marker procollagen type II propeptide (PIICP) was useful in differentiating between control and diseased dogs with the best combination of sensitivity and specificity. The four biomarkers showed high area under the curve (AUC) values., Conclusions: The results indicate that plasma biomarkers can be used as a screening tool for canine hip dysplasia. Although the cutoff values and diagnostic ability of the biomarkers used in this study show promising results, the sources of individual variability should be addressed. Future studies with larger groups of dogs are needed to correlate plasma levels in serum and synovial fluid during clinical disease., (© 2019 American Society for Veterinary Clinical Pathology.)

This study compares serum and urine concentrations of relevant protein biomarkers among adult dogs with or without radiographic canine hip dysplasia (CHD). Adult (≥2 years of age), client-owned dogs (n = 74) radiographically categorized as having at least "good" hips (n = 49) or having "mild," "moderate," or "severe" hip dysplasia (n = 25) by the Orthopedic Foundation for Animals (OFA). Urine and serum samples were obtained from each dog at a single time-point and processed and analyzed for relevant protein biomarkers. Urinary concentrations of CTX-II (p < 0.001) and TIMP-1 (p = 0.002) were significantly lower in dogs with CHD compared to dogs with no CHD. ROC curve analyses were successful in establishing a panel of four biomarkers (urinary CTX-I and II, serum MMP-9, and serum PIICP) with high discriminatory capability for the presence or absence of hip dysplasia in adult dogs (AUC = 0.89). Urine and serum biomarkers can distinguish adult dogs with radiographic CHD from those with no CHD with a sensitivity of 0.95 and specificity of 0.77 using ROC analysis with AUC 0.89. Clinical Significance: This finding suggests that this simple, minimally invasive diagnostic technique has potential for discriminating dysplastic dogs from dogs with normal hips, with possible translational application to humans based on similar etiopathogenesis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-5, 2019., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Context: Individuals with an anterior cruciate ligament reconstruction (ACLR) are at an increased risk of developing posttraumatic osteoarthritis. How osteoarthritis risk factors, such as increased body mass index (BMI), may influence early changes in joint tissue metabolism is unknown., Objective: To determine the association between BMI and type 2 cartilage turnover in individuals with an ACLR., Design: Cross-sectional study., Setting: Research laboratory., Patients or Other Participants: Forty-five individuals (31 women, 14 men) with unilateral ACLR at least 6 months earlier who were cleared for unrestricted physical activity., Main Outcome Measure(s): Body mass index (kg/m 2 ) and type 2 collagen turnover were the primary outcomes. Body mass index was calculated from objectively measured height and mass. Serum was obtained to measure type 2 collagen turnover, quantified as the ratio of degradation (collagen type 2 cleavage product [C2C]) to synthesis (collagen type 2 C-propeptide [CP2]; C2C : CP2). Covariate measures were physical activity level before ACLR (Tegner score) and current level of disability (International Knee Documentation Committee Index score). Associations of primary outcomes were analyzed for the group as a whole and then separately for males and females., Results: Overall, greater BMI was associated with greater C2C : CP2 ( r = 0.32, P = .030). After controlling for covariates (Tegner and International Knee Documentation Committee Index scores), we identified a similar association between BMI and C2C : CP2 (partial r = 0.42, P = .009). Among women, greater BMI was associated with greater C2C : CP2 before ( r = 0.47, P = .008) and after (partial r = 0.50, P = .008) controlling for covariates. No such association occurred in men., Conclusions: Greater BMI may influence greater type 2 collagen turnover in those with ACLR. Individuals, especially women, who maintain or reduce BMI may be less likely to demonstrate greater type 2 collagen turnover ratios after ACLR.

N-terminal propeptide of type II collagen (PIINP) is a biomarker reflecting cartilage formation. PIINP exists in two main splice variants termed as type IIA and type IIB collagen NH₂-propeptide (PIIANP, PIIBNP). PIIANP has been widely recognized as a cartilage formation biomarker. However, the utility of PIIBNP as a marker in preclinical and clinical settings has not been fully investigated yet. In this study, we aimed to characterize an antibody targeting human PIIBNP and to develop an immunoassay assessing type II collagen synthesis in human blood samples. A high sensitivity electrochemiluminescence immunoassay, hsPRO-C2, was developed using a well-characterized antibody against human PIIBNP. Human cartilage explants from replaced osteoarthritis knees were cultured for ten weeks in the presence of growth factors, insulin-like growth factor 1 (IGF-1) or recombinant human fibroblast growth factor 18 (rhFGF-18). The culture medium was changed every seven days, and levels of PIIBNP, PIIANP, and matrix metalloproteinase 9-mediated degradation of type II collagen (C2M) were analyzed herein. Serum samples from a cross-sectional knee osteoarthritis cohort, as well as pediatric and rheumatoid arthritis samples, were assayed for PIIBNP and PIIANP. Western blot showed that the antibody recognized PIIBNP either as a free fragment or attached to the main molecule. Immunohistochemistry demonstrated that PIIBNP was predominately located in the extracellular matrix of the superficial and deep zones and chondrocytes in both normal and osteoarthritic articular cartilage. In addition, the hsPRO-C2 immunoassay exhibits acceptable technical performances. In the human cartilage explants model, levels of PIIBNP, but not PIIANP and C2M, were increased (2 to 7-fold) time-dependently in response to IGF-1. Moreover, there was no significant correlation between PIIBNP and PIIANP levels when measured in knee osteoarthritis, rheumatoid arthritis, and pediatric serum samples. Serum PIIBNP was significantly higher in controls (KL0/1) compared to OA groups (KL2/3/4, p = 0.012). The hsPRO-C2 assay shows completely different biological and clinical patterns than PIIANP ELISA, suggesting that it may be a promising biomarker of cartilage formation.

Background: Kashin-Beck disease (KBD) is an endemic, chronic, degenerative osteoarthropathy. KBD is usually diagnosed by using X-ray image and clinical symptoms, lacking of serological biomarkers. The serum level of PIICP, PIIANP, and PIIBNP can specifically reflect the damage of the cartilage. So, in this study, the serum levels of PIICP, PIIANP, and PIIBNP were detected in order to determine whether they can be used as potential biomarkers for the diagnosis of KBD., Method: Using a status survey, the survey sites were selected in the KBD historical endemic areas and non-endemic areas in Jilin and Heilongjiang provinces. All local residents have undergone clinical examination, X-ray examination of the hands and knees, and questionnaire survey. A total of 554 people were surveyed, and 184 residents who are eligible for inclusion criteria were selected as our subjects. Fifty-six cases were diagnosed as KBD and 63 individuals were included as internal control and 65 subjects were included as external control. And blood samples of surveyed subjects were collected, and the serum was separated to detect the levels of PIICP, PIIANP, and PIIBNP by ELISA. Statistical analysis was performed using the SPSS software., Results: There were no statistically significant differences in age and sex among the three groups. The Kruskal-Wallis H test showed that the serum levels of PIICP, PIIANP, and PIIBNP were significantly different among the three groups. Multiple comparisons using Dunnett's T3 test revealed that serum levels of PIICP, PIIANP, and PIIBNP were significantly lower in KBD patients than in internal and external control. However, there was no significant difference between the internal and external control., Conclusions: The results preliminarily indicated that the levels of PIICP, PIIANP, and PIIBNP in serum could reflect the abnormal synthesis of type II collagen in KBD patients and suggested that these indicators might be used as potential biomarkers for the diagnosis of KBD.

Biochemical markers reflecting joint remodeling in osteoarthritis (OA) are a promising diagnostic tool. The aim of this study was to investigate serum levels of candidate biomarkers in subjects with and without knee OA and assess their correlation with clinical parameters and knee structural damage. 56 patients with primary knee OA and 31 healthy controls participated in this study. Patients were separated into two groups: isolated knee OA and generalized OA. Clinical parameters were obtained by validated self-reported questionnaires and a visual analogue scale. Serum levels of cartilage oligomeric protein (COMP), matrix metalloproteinase-3 (MMP-3), and Coll2-1 were quantified by enzyme-linked immunosorbent assay. Knee structural damage was determined by plain X-ray and 1.5 T magnetic resonance imaging (MRI), using Kellgren-Lawrence (KL) grading scale and Whole-Organ Magnetic Resonance Imaging Score (WORMS), respectively. Compared to controls, patients had significantly higher median serum COMP (985 vs. 625 ng/ml; p < 0.001) and MMP-3 (36.85 vs. 22.10 ng/ml; p = 0.003) levels. Patients with radiographic evidence of KLII/III knee OA had greater median COMP levels than KLI patients (1095 vs. 720 ng/ml; p = 0.001). In the generalized OA group, mean MMP-3 levels were higher than in the isolated knee OA group (30.40 vs. 55.13 ng/ml; p < 0.001). COMP correlated positively with WORMS (r s  = 0.454, p < 0.001) and MMP-3 (r s  = 0.337, p = 0.003). Cut-off values for serum COMP and MMP-3 were determined. We observed higher serum COMP and MMP-3 levels in knee OA patients compared to controls. COMP may reflect knee structural damage, while MMP-3-OA "generalization".

Objective: The study aims to explore the effects of artesunate on insulin-like growth factor-1 (IGF-1), Osteopontin (OPN), and C-telopeptides of type II collagen (CTX-II) in serum, synovial fluid (SF), and cartilage tissues of rats with osteoarthritis (OA)., Methods: OA models were established. Normal model, artesunate, and Viatril-S groups (20 rats respectively) were set. Enzyme-linked immunosorbent assay, IHC staining, and quantitative real-time polymerase chain reaction were conducted to calculate IGF-1, OPN, and CTX-II levels in serum, SF, and cartilage tissues of rats. The pathological changes in cartilage tissues were evaluated with Mankin score and Hematoxylin-Eosin staining., Results: Compared with the normal group, the model group showed increased IGF-1 level; decreased OPN, CTX-II levels in the serum and SF; and contrary results were seen in the cartilage tissues. A gradual ascending IGF-1 level and descending OPN and CTX-II levels existed in the serum and SF in the artesunate and Viatril-S groups after 2 weeks. The model group showed the most obvious pathological changes and highest Mankin score compared with the other groups. Higher IGF-1 level and lower OPN, CTX-II levels were exhibited in the cartilage tissue in the artesunate and Viatril-S groups but not in the model group., Conclusion: Artesunate and Viatril-S inhibit OA development by elevating IGF-1 level and reducing OPN and CTX-II levels., (© 2017 S. Karger AG, Basel.)

Objective: Cartilage homeostasis relies on a balance of catabolism and anabolism of cartilage matrix. Our goal was to evaluate the burden of radiographic osteoarthritis and serum levels of type IIA procollagen amino terminal propeptide (sPIIANP), a biomarker representing type II collagen synthesis, in osteoarthritis., Methods: OA burden was quantified on the basis of radiographic features as total joint faces with an osteophyte, joint space narrowing, or in the spine, disc space narrowing. sPIIANP was measured in 1,235 participants from the Genetics of Generalized Osteoarthritis study using a competitive enzyme-linked immunosorbent assay. Separate multivariable linear regression models, adjusted for age, sex, and body mass index and additionally for ipsilateral osteophytes or joint/disc space narrowing, were used to assess the independent association of sPIIANP with osteophytes and with joint/disc space narrowing burden in knees, hips, hands and spine, individually and together., Results: After full adjustment, sPIIANP was significantly associated with a lesser burden of hip joint space narrowing and knee osteophytes. sPIIANP was associated with a lesser burden of hand joint space narrowing but a greater burden of hand osteophytes; these results were only evident upon adjustment for osteoarthritic features in all other joints. There were no associations of sPIIANP and features of spine osteoarthritis., Conclusions: Higher cartilage collagen synthesis, as reflected in systemic PIIANP concentrations, was associated with lesser burden of osteoarthritic features in lower extremity joints (knees and hips), even accounting for osteoarthritis burden in hands and spine, age, sex and body mass index. These results suggest that pro-anabolic agents may be appropriate for early treatment to prevent severe lower extremity large joint osteoarthritis.

Both vitamin D and collagen have roles in osteocartilaginous homeostasis. We evaluated the association between the circulating 25-hydroxyvitamin D (25(OH)D) type I and II collagen degradation products (CTx-I, and CTx-II), and four vitamin D receptor gene ( VDR ) polymorphisms, in Italian males affected by low back pain (LBP) due to herniation/discopathy and/or vertebral osteochondrosis. FokI, BsmI, ApaI, and TaqI VDR -polymorphisms were detected through PCR-restriction fragment length polymorphism (RFLP), and circulating 25(OH)D, CTx-I and CTx-II were measured by immunoassays in 79 patients (of which 26 had osteochondrosis) and 79 age-, sex- and body mass index (BMI)-matched healthy controls. Among all 158 subjects, carriers of FF and Ff genotypes showed lower 25(OH)D than ff , which suggested a higher depletion of vitamin D in F allele carriers. Higher CTx-I concentrations were observed in TT versus Tt among controls, and Tt versus tt among LBP cases, which suggested a higher bone-cartilaginous catabolism in subjects bearing the T allele. Higher CTx-II concentrations were observed in patients with osteochondrosis bearing FF , bb , TT , or Aa genotypes in comparison with hernia/discopathy patients and healthy controls. Vertebral osteochondrosis shows peculiar genotypic and biochemical features related to vitamin D and the osteocartilaginous metabolism. Vitamin D has roles in the pathophysiology of osteochondrosis., Competing Interests: The authors declare no conflict of interest.

Background The use of bone turnover markers in clinical practice and research in younger people is limited by the lack of normative data and understanding of common causes of variation in bone turnover marker values in this demographic. To appropriately interpret bone turnover markers, robust reference intervals specific to age, development and sex are necessary. This study aimed to determine reference intervals of bone turnover markers in females aged 16-25 years participating in the Safe-D study. Methods Participants were recruited through social networking site Facebook and were asked to complete an extensive, online questionnaire and attend a site visit. Participants were tested for serum carboxy-terminal cross-linking telopeptide of type 1 collagen and total procollagen type 1 N-propeptide using the Roche Elecsys automated analyser. Reference intervals were determined using the 2.5th to 97.5th percentiles of normalized bone turnover marker values. Results Of 406 participants, 149 were excluded due to medical conditions or medication use (except hormonal contraception) which may affect bone metabolism. In the remaining 257 participants, the reference interval was 230-1000 ng/L for serum carboxy-terminal cross-linking telopeptide of type 1 collagen and 27-131  µg/L for procollagen type 1 N-propeptide. Both marker concentrations were inversely correlated with age and oral contraceptive pill use. Therefore, intervals specific to these variables were calculated. Conclusions We defined robust reference intervals for cross-linking telopeptide of type 1 collagen and procollagen type 1 N-propeptide in young females grouped by age and contraceptive pill use. We examined bone turnover markers' relationship with several lifestyle, clinical and demographic factors. Our normative intervals should aid interpretation of bone turnover markers in young females particularly in those aged 16 to 19 years where reference intervals are currently provisional.

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.

Pseudoachondroplasia (PSACH) is an autosomal dominant osteochondrodysplasia caused by mutations in the gene encoding cartilage oligomeric matrix protein (COMP). Accurate clinical diagnosis of PSACH is sometimes difficult. Here, we identified a novel COMP mutation (c.1675G>A, p.Glu559Lys) in a Chinese PSACH family. We detected the plasma levels of COMP and type II collagen (CTX-II) in the four affected individuals. The results showed the levels of plasma COMP significantly decreased and plasma CTX-II significantly increased in the three PSACH patients with COMP mutation. However, both plasma levels of COMP and CTX-II were not to have found significant difference between the presymptomatic carrier and the age-matched subjects. In vitro analysis and immunofluorescence displayed wild type COMP homogenously expressed in cytoplasm, but mutant proteins were irregularly accumulated inside the HEK-293 cells. Western blot revealed that the quantity of the mutant COMP was more compared to wild type COMP in cells after transfection for 12 hours and 24 hours. Subsequently, 3D structural analysis showed three changes have taken place in secondary structure of the mutant COMP. In conclusion, the novel mutation of COMP may result in intracellular accumulation of the mutant protein. Decreased plasma COMP and increased plasma CTX-II may potentially serve as diagnostic markers of PSACH but may not be applicable in the presymptomatic carrier.

Differences in cartilage biomarkers have been noted in patients with anterior cruciate ligament tears, but little is known about any similar relationship with shoulder instability. This study evaluated the relationship between serum cartilage biomarkers and shoulder instability. The authors present a prospective cohort study of young athletes followed from 2006 to 2010. A nested case-control analysis was conducted within this cohort to evaluate the association between preinjury collagen type II cleavage (a marker for type II collagen cleavage) and procollagen II carboxy propeptide (a marker of cartilage synthesis) and the subsequent likelihood of shoulder instability during the 4-year follow-up period. Preinjury collagen type II cleavage and procollagen II carboxy propeptide levels in 51 subjects who had shoulder instability were compared with levels in 210 subjects without documented anterior cruciate ligament or shoulder instability (control group) with commercially available enzyme-linked immunosorbent assay kits. Mean preinjury collagen type II cleavage levels in patients who subsequently had shoulder instability were significantly lower than those in the control group (73.91 vs 79.24 pg/mL, P=.03). No significant difference was found in preinjury procollagen II carboxy propeptide levels compared with the control group (359.94 vs 396.37, P=.24). This study is the first to examine the relationship between baseline collagen biomarkers and subsequent shoulder instability. The finding of lower baseline collagen type II cleavage levels in patients with subsequent shoulder instability may represent a genetic predisposition or a compensatory mechanism by which cartilage degradation is decreased in those who are more likely to have instability. [Orthopedics. 2017; 40(1):34-36.]., (Copyright 2016, SLACK Incorporated.)

Background: Early diagnosis of osteoarthritis (OA) is difficult. Cartilage oligomeric matrix protein (COMP) and crosslinked C-telopeptides of type II collagen (CTX-II) are two markers which can potentially predict the destruction of articular cartilage of early OA. To comprehensively evaluate the diagnosis value of serum COMP and CTX-II markers in OA, the longitudinal and combined measurement of serum COMP and CTX-II were performed at different stages of pathological process of OA in adult rabbits with OA, compared with the sham-operated rabbits., Methods: Thirty-six adult white rabbits were randomly divided into two groups, the OA group and the control group (n = 18 per group). OA models were established by anterior cruciate ligament transection. Sham operations were performed in the control group. Before the surgery and at weeks 2, 4, 6, 8, 10, and 12 after surgery, serum CTX-II and COMP concentrations were detected using sandwich-ELISA in all rabbits. Three rabbits in each group were killed at weeks 2, 4, 6, 8, 10, and 12 after surgery, and femoral condyle specimens were collected. Histological changes in articular cartilage were evaluated according to the Mankin scoring criteria., Results: At each time point, the Mankin scores and serum concentrations of CTX-II and COMP were significantly higher in the OA group than in the control group. In addition, in the OA group, there was a significant relationship between the CTX-II and COMP concentrations and the Mankin score., Conclusions: Early dynamic combined detection of serum CTX-II and COMP concentrations is effective for early OA diagnosis and evaluation of OA severity.

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.

Background: Psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) are chronic inflammatory rheumatic diseases with complex origins. Both are characterized by altered extracellular matrix remodeling in joints and entheses that results in destructive and osteochondral proliferative lesions. There is a need for biomarkers reflecting core disease pathways for diagnosis and disease mapping. Pro-C2 reflects mature cartilage collagen type IIB formation, while C-Col10 represents turnover of type X collagen, which is exclusively expressed by hypertrophic chondrocytes. The objectives of this study were to study cartilage metabolism in axSpA and PsA by assessing Pro-C2 and C-Col10 and to evaluate their diagnostic utility against a healthy reference population., Methods: Patients with PsA (n = 101) or axSpA (n = 110) were recruited consecutively from three rheumatology outpatient clinics. Demographic and clinical disease measures were recorded. Pro-C2 and C-Col10 were quantified in serum by using newly developed and specific competitive enzyme-linked immunosorbent assays based on monoclonal antibodies. One-way analysis of variance and Tukey's multiple comparison tests were performed on log-transformed data. ROC curve analysis was carried out to evaluate their discriminative power., Results: Pro-C2 levels in serum were significantly increased in both axSpA (median concentration 1.11 ng/ml, 0.67-1.64) and PsA (median concentration 1.03 ng/ml, 0.53-1.47) compared with healthy controls (median concentration 0.30 ng/ml, 0.16-0.41) (p < 0.0001). Pro-C2 did not differ according to treatment. C-Col10 was slightly but equally elevated in the PsA and axSpA groups vs. the control group, but it was significantly lower in patients with axSpA undergoing tumor necrosis factor-α inhibitor (TNFi) treatment. ROC curve analysis revealed AUCs of 0.85 (95 % CI 0.79-0.89) for axSpA and 0.81 (95 % CI 0.75-0.86) for PsA., Conclusions: These findings indicate that cartilage collagen metabolism was enhanced in the axSpA and PsA groups compared with the healthy control group. The lower C-Col10 level in patients with axSpA undergoing TNFi treatment may reflect that hypertrophic chondrocytes in axSpA are targeted by TNFi. ROC curve analysis showed a diagnostic potential for Pro-C2 in axSpA and PsA.

The aim of the study was to assess the possible association between type II collagen turnover seromarkers and disease profile in patients with axial spondyloarthritis (SpA) and psoriatic arthritis (PsA). Outpatients with axial SpA (n = 110) or PsA (n = 101) underwent clinical examination including disease activity measures and HLA-B27 typing. The procollagen IIA N-terminal peptide (PIIANP) and a matrix metalloproteinase-generated type II collagen fragment (C2M) were quantified in serum by ELISA. C2M was higher in SpA than in controls, 0.41 versus 0.36 ng/ml (p = 0.004), while PIIANP did not differ between patients and healthy subjects, 2252 versus 2142 ng/ml (p = 0.13). However, DMARD-naïve SpA patients had higher PIIANP, 2461 ng/ml (p = 0.01) and C2M, 0.44 ng/ml (p = 0.0007) levels than controls, and PIIANP correlated with CRP (ρ = 0.34). C2M was lower in SpA smokers, 0.36 ng/ml versus non-smokers, 0.43 ng/ml (p = 0.02), while PIIANP was higher in HLA-B27 positive, 2312 ng/ml versus negative patients, 2021 ng/ml (p = 0.03). In PsA, PIIANP and C2M did not differ between patients and controls, but PIIANP was elevated in patients not receiving DMARDs, 2726 ng/ml. In PsA, PIIANP and C2M did not differ according to smoking and HLA-B27. Cartilage degradation assessed by C2M is increased in SpA irrespective of treatment but not in PsA. Cartilage synthesis reflected by PIIANP is increased in untreated SpA and PsA. PIIANP correlates with CRP in SpA while not in PsA. In DMARD-naïve SpA but not in PsA, HLA-B27 positivity and smoking are associated with a chondro-proliferative metabolic pattern.

Brucellosis is one of the most widespread zoonotic diseases, with the most frequent complication being osteoarticular changes. The aim of this study was to assess the changes of C-terminal telopeptide of type II collagen (CTX-II) in patients infected with brucellosis. A total of 84 brucellosis patients and 43 volunteers were selected and divided into brucellosis vs. control groups. Serum samples were subjected to serological tests for brucellosis, and CTX-II levels in all samples were measured simultaneously with ELISA. The results showed that serum CTX-II levels in human brucellosis were higher than those of healthy controls, without a statistically significant difference, but serum CTX-II levels in male patients were significantly higher than those of female patients (P<0.05). This finding could indicate the biological changes in the cartilage and bone in human brucellosis., (Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.)

The aim of this study was to evaluate the use of serum type II collagen cleavage epitope and serum hyaluronic acid as biomarkers for treatment monitoring in osteoarthritic dogs. For this purpose, a treatment model based on mesenchymal stem cells derived from adipose tissue combined with plasma rich in growth factors was used. This clinical study included 10 dogs with hip osteoarthritis. Both analytes were measured in serum at baseline, just before applying the treatment, and 1, 3, and 6 months after treatment. These results were compared with those obtained from force plate analysis using the same animals during the same study period. Levels of type II collagen cleavage epitope decreased and those of hyaluronic acid increased with clinical improvement objectively verified via force plate analysis, suggesting these two biomarkers could be effective as indicators of clinical development of joint disease in dogs.

This study reports a new strategy for simultaneous detection of the C-telopeptide fragments of type II collagen (CTX-II) as a biomarker of osteoarthritis (OA) using a fluoro-microbeads guiding chip. As osteoarthritis progresses, the joint components including matrix and cartilage are degraded by proteases. The degraded products such as CTX-II are released into the serum and urine, and the CTX-II concentration in body fluids reflects OA progression. Because the CTX-II has heterogeneous epitope structure in serum (sCTX-II; homodimers) and urine (uCTX-II; monomers or variant monomers), a multiple-sensing device enabling both sandwich and competitive-type immunoassays is required. For multiple assessments of serum and urinary CTX-II, we designed a fluoro-microbeads guiding chip (FMGC) containing multiple sensing areas and connecting channels. Using the approach, the sandwich (sCTX-II) and competition (uCTX-II) assays could be simultaneously performed on a single chip. We designed a fluidic control device enabling selective control of the open-close function of FMGC channels. The immune-specific signal was quantitatively analyzed by counting the number of fluorescent microbeads from the registered images. The results from the developed FMGC assay showed high correlation with those obtained in ELISA. The completion time of the FMGC assay was 24-fold and 3.5-fold shorter than the ELISA for urinary and serum CTX-II. Taken together, it enabled the simultaneous detection of both sCTX-II and uCTX-II. This FMGC-based assay would be a promising tool for monitoring of osteoarthritis., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Osteoarthritis (OA) is the most frequent articular disease and a leading cause of disability. There is a need for effective treatments able to slow the progression of disease. Some of the available treatments are dietary supplements providing natural components. Recent studies have shown that estrogen deficiency contributes to the pathophysiological events of OA progression., Methods: We have used the anterior cruciate ligament transection model of OA in ovariectomised rats to study the effects of BIS076, a new formulation of a natural porcine cartilage extract associated with hydroxyapatite (as a source of calcium) and vitamin D3. Cartilage degradation, proteoglycan depletion and synovitis were followed by histochemistry. Effects on bone microstructure were determined by μCT. The levels of biomarkers in serum and inflammatory mediators in knee homogenates were measured by luminex or ELISA., Results: Oral administration of BIS076 reduced articular cartilage damage and serum levels of cartilage degradation markers C-telopeptide of type II collagen and cartilage oligomeric matrix protein, as well as matrix metalloproteinase-3. The local inflammatory response was down-regulated by BIS076 with lower production of pro-inflammatory cytokines and prostaglandin E2 in joint tissues. In addition, BIS076 was effective on metaphyseal bone alterations as this formulation increased volumetric bone mineral density and improved bone micro-architecture. These effects were related to the modification of bone metabolism reflected by changes in bone biomarkers with reductions in the ratio receptor activator of nuclear factor κB ligand/osteoprotegerin and the levels of tartrate-resistant acid phosphatase-5b, suggesting an inhibitory activity of BIS076 on trabecular bone resorption., Conclusions: We have demonstrated the protective properties of a new formulation (BIS076) on joint lesion and bone alterations in an experimental model of OA in ovariectomised rats. This study supports the interest of BIS076 in OA treatments.

A great body of evidence has shown that extracellular matrix (ECM) alterations are present in the major types of cardiac diseases: ischemic heart disease, heart disease associated with pressure overload, heart disease associated with volume overload, and intrinsic myocardial disease or cardiomyopathy. Collagen, type I and III, is the principal structural protein found in the myocardium and its pro- or telopeptides are released into the circulation during the course of cardiovascular diseases. Therefore, these peptides may reflect collagen synthesis and break-down and also represent a much more useful tool to address ECM changes from a distance. Clinical trials have been performed during recent years to examine the usage of these peptides as diagnostic or prognostic biomarkers in heart failure (HF) patients. This review aims to summarize published data concerning cardiac ECM and its circulating biomarkers. Studies that focused on collagen metabolism related biomarkers in patients with HF are analyzed. Finally, limitations associated with the clinical use of the aforementioned biomarkers are also discussed., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Introduction: Rheumatoid arthritis (RA) patients with autoantibodies against collagen type II (CII) are characterized by acute RA onset with elevated inflammatory measures and early joint erosions as well as increased production of tumor necrosis factor-α (ΤΝF-α) by peripheral blood mononuclear cells (PBMC) stimulated by anti-CII immune complexes (IC) in vitro. Polymorphonuclear granulocytes (PMN) are abundant in RA synovial fluids, where they might interact directly with anti-CII IC in the articular cartilage, but no studies have investigated PMN responses towards anti-CII IC. The aim was to investigate whether PMN react towards anti-CII IC, and to what extent such reactivity might relate to the clinical acute onset RA phenotype associated with elevated levels of anti-CII., Methods: PMN and PBMC isolated from healthy donors were stimulated with IC made with a set of 72 baseline patient sera (24 anti-CII positive, 48 anti-CII negative) chosen from a clinically well-characterized RA cohort with two-year radiological follow-up with Larsen scoring. PMN expression of cluster of differentiation (CD)11b, CD66b, CD16 and CD32 was measured by flow cytometry, whereas PMN production of myeloperoxidase (MPO) and interleukin (IL)-17, and PBMC production of ΤΝF-α was measured with enzyme linked immunosorbent assay., Results: PMN expression of CD11b, CD66b and MPO, and PBMC production of ΤΝF-α were upregulated whereas PMN expression of CD16 and CD32 were downregulated by anti-CII IC. CD16, CD66b, and MPO production correlated to serum anti-CII levels (Spearman's ρ = 0.315, 0.675 and 0.253, respectively). CD16 was associated with early joint erosions (P = 0.024, 0.034, 0.046 at baseline, one and two years) and CD66b was associated with changes in joint erosions (P = 0.017 and 0.016, at one and two years compared to baseline, respectively). CD66b was associated with baseline C-reactive protein and PBMC production of ΤΝF-α was associated with baseline erythrocyte sedimentation rate, in accordance with our earlier findings. No clinical associations were observed for MPO or IL-17., Conclusion: PMN responses against anti-CII IC are more closely associated with early joint erosions than are PBMC cytokine responses. PMN reactivity against anti-CII IC may contribute to joint destruction in newly diagnosed RA patients with high levels of anti-CII.

Introduction: Our objective was to find out if there are antibodies binding to homocitrulline-containing type I and II collagen carboxyterminal telopeptides in sera of patients with rheumatoid arthritis (RA), and if these antibodies cross-react with citrulline and homocitrulline in the same peptide sequence., Methods: A total of 72 RA and 72 control sera were analyzed for binding using enzyme-linked immunosorbent assay to citrulline- or homocitrulline-containing type I and II collagen carboxyterminal telopeptides, as well as to cyclic citrullinated peptide (CCP) and to mutated citrullinated vimentin (MCV). Specificities of the antibodies were tested using inhibition-ELISA., Results: Of the RA sera, 39 (54%) and 41 (57%) were positive for binding to CCP and MCV, respectively. Further, 34 (47%) and 30 (42%) of the patients had specific antibodies binding to and being inhibited by citrulline-containing type I collagen telopeptides and by citrulline-containing type II collagen carboxyterminal telopeptides, respectively. The corresponding figures regarding homocitrulline-containing type I and homocitrulline-containing type II collagen telopeptides were 16 (22%) and 14 (19%). Most of the patients, who were seropositive for citrullinated peptides, showed binding in multiple assays. A total of 10 (14%) RA patients were positive for all the tested peptide pairs, while 28 (39%) of them had antibodies that contained overlapping specifities between citrulline and homocitrulline in the same peptide sequence., Conclusions: Antibodies to both citrulline and homocitrulline containing type I and II collagen telopeptides can be found in sera of RA patients. These antibodies are not constant from one RA patient to another, but contain separate or overlapping specificities within the same peptide sequence varying between individuals. Our results suggest some relationship between citrulline and homocitrulline-recognizing antibodies, since homocitrulline antibodies exist mainly in individuals seropositive to anti-CCP and anti-MCV.

Aims: To investigate the association between type II collagen fragments and the presence of knee osteoarthritis (OA) in the Tunisian population and to determine whether this biomarker can predict X-ray progression of this disease., Methods: Type II collagen C-telopeptide (uCTX-II) and helical peptide (sHelix-II) were assessed in 125 female patients with knee osteoarthritis aged 54 ± 8 years over 2 years and 57 female age-matched controls. The markers were measured at baseline, 1 and 2 yrs' follow-up corresponding to x-ray time points., Results: Only urinary CTX-II values were significantly 48% higher in knee OA patients compared with controls (p=0.001). The longitudinal changes over 2 yrs in Helix-II were also significantly associated with Joint Space Narrowing: JSN (p=0.03). Over the 2-yr study period average CTX-II levels were not significantly higher in progressor compared with non-progressor (339.96 vs 256.00; NS)., Conclusion: The data presented here suggest that CTX-II may be useful to identify patients with knee OA. These results demonstrate significantly association between progression of this disease and alterations levels of Helix-II.

The aim of this study was to enable measurement of cartilage formation by a novel biomarker of type II collagen formation. The competitive enzyme-linked immunosorbent assay (ELISA) Pro-C2 was developed and characterized for assessment of the beta splice variant of type II procollagen (PIIBNP). This is expected to originate primarily from remodeling of hyaline cartilage. A mouse monoclonal antibody (Mab) was raised in mouse, targeting specifically PIIBNP (QDVRQPG) and used in development of the assay. The specificity, sensitivity, 4-parameter fit and stability of the assay were tested. Levels of PIIBNP were quantified in human serum (0.6-2.2 nM), human amniotic fluid (163-188 nM) and sera from different animal species, e.g., fetal bovine serum (851-901 nM) with general good linearity (100% (SD 7.6) recovery) and good intra- and inter-assay variation (CV% < 10). Dose (0.1 to 100 ng/mL) and time (7, 14 and 21 days) dependent release of PIIBNP were evaluated in the conditioned medium from bovine cartilage explants (BEX) and human cartilage explants (HEX) upon stimulation with insulin-like growth factor (IGF-1), transforming growth factor (TGF)-β1 and fibroblastic growth factor-2 (FGF-2). TGF-β1 and IGF-1 in concentrations of 10-100 ng/mL significantly (p < 0.05) induced release of PIIBNP in BEX compared to conditions without treatment (WO). In HEX, IGF-1 100 ng/mL was able to induce a significant increase of PIIBNP after one week compared to WO. FGF-2 did not induce a PIIBNP release in our models. To our knowledge this is the first assay, which is able to specifically evaluate PIIBNP excretion. The Pro-C2 assay seems to provide a promising and novel marker of type II collagen formation.

Objective: To evaluate the role of three cartilage-derived biomarkers on osteoarthritis (OA): urinary C-terminal telopeptide (uCTX-II), serum cartilage oligomeric protein (sCOMP), and serum MMP degraded type II collagen (sC2M)., Subjects and Methods: Samples from 3582 individuals from the Rotterdam Study, the Genetics osteoArthritis and Progression (GARP), the Chingford Study and the TwinsUK cohort were assayed using enzyme-linked immune sorbent assays. Log10 of concentration levels were correlated with risk of hip, hand and knee OA, hip and knee OA severity and incidence, and progression of knee OA, adjusting for age, gender and body mass index (BMI). Results were meta-analysed to assess overall significance., Results: After adjusting for covariates, sCOMP was associated with knee OA and hip and knee OA incidence. Furthermore, sC2M was associated with knee OA incidence and progression. After adjustment for multiple tests (Bonferroni P < 0.002) only the association between sCOMP and knee OA remained significant (odds ratio (OR) = 3.26 (95%CI 1.63-10.1) P = 0.0008 for each standard deviation (SD) increase in biomarker levels). Levels of uCTX-II were significantly associated with risk of hand, hip and knee OA, progression and incidence of knee OA. A receiver operating characteristics (ROC) analysis showed a consistent improvement in prediction of knee OA progression from an average area under the curve (AUC) is 0.646 for age, sex and BMI alone to an AUC = 0.668 including uCTX-II for prediction., Conclusions: uCTX-II is the most informative biochemical marker for prediction of OA. Both sCOMP and C2M showed some association with OA, thus indicating that they are descriptive of disease activity., (Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

This study aims to determine the effect of age-related cartilage turnover on the serum C-telopeptide of type II collagen (CTX-II) and osteocalcin (OC) levels in growing rabbits with and without surgically induced osteoarthritis. Twenty-four New Zealand male 3-month-old rabbits were randomized into three operated groups (n=6 per group, with surgically induced osteroarthritis in the right knee; after blood sampling, the knees were harvested following euthanization at 2, 3, and 6 months after surgery) and a control group (n=6, blood samples were obtained monthly between 3 and 15 months). Histomorphologically, the medial femoral condyles, particularly the central parts, harbored the most severe osteoarthritic changes among the operated rabbits. The serum levels of CTX-II and OC decreased in the controls from 3 to 11 months and then remained stable. No significant differences in the serum CTX-II and OC levels between the osteoarthritic rabbits and controls were observed. The osteoarthritic-to-normal ratios (ONRs, the ratios of serum CTX-II or OC levels in osteoarthritic rabbits to those of the controls at same ages) enabled an overall assessment of osteoarthritis and age-related cartilage turnover. Elevated CTX-II ONRs were observed in rabbits with mild to advanced osteoarthritis. However, the OC ONRs were unhelpful in assessing osteoarthritic growing rabbits.

Joint damage in rheumatoid arthritis (RA) is characterized by cartilage and bone loss resulting in pain, deformity, and loss of joint function. Anti-citrullinated protein antibody (ACPA) has been implicated in RA pathogenesis and predicts radiographical joint damage and clinical severity. Therefore, the purpose of this study was to assess bone loss by micro-CT, histological joint damage, and ACPA levels using a mouse model of RA. Arthritis was induced by immunizing DBA/1 mice with autologous citrullinated type II mouse collagen (CIT-CII) weekly for 4 weeks. Mice immunized with autologous CII served as controls. At week 5, mice were killed, ACPA levels determined, and micro-CT performed to quantitatively analyze bone damage. Micro-CT analysis revealed significant loss of bone density, volume, and surface (p < 0.05) in bone peripheral to the inflamed joints of CIT-CII animals compared to CII controls. Histological staining demonstrated cartilage, proteoglycan, joint collagen, and bone collagen loss in the CIT-CII group compared to CII. Serum ACPA levels were increased (p = 0.03) in the CIT-CII group compared to CII, and these levels were inversely correlated with bone quantity and quality. In this study, we demonstrate that immunization with autologous CIT-CII initiates significant systemic bone and articular cartilage loss in the absence of adjuvant. Significant inverse correlations of circulating ACPA and bone quality/quantity were present. ACPA levels predict the adverse bone morphological changes in this model of early RA.

The aim of this study was to elucidate whether the levels of serum biomarkers reflect the progression of osteoarthritis (OA) induced by different levels of exercise. Thirty-five Wistar rats subjected to anterior cruciate ligament transaction (ACLT) were divided into three groups: Control, moderate running, and intense running. Twelve rats (moderate running without ACLT) were allocated as a naive group. Running was performed on a motorized treadmill, at a speed of 18 m/min for 30 min/day (moderate and naive) or 60 min/day (intense) for 3 days per week. After 2 or 4 weeks, OA histopathology in the knees was evaluated using the Osteoarthritis Research Society International (OARSI) score, and the serum levels of cleaved collagen type II (C2C) and procollagen II C-propeptide (CPII) were analyzed. The OARSI score deteriorated in the intense running group after 2 weeks and the serum C2C/CPII ratio suggested the development of OA. At 4 weeks, the C2C/CPII ratio suggested there would be deterioration in the OARSI score but the score did not differ significantly between the moderate and intense running groups. C2C/CPII ratio had 13-25% correlation with the OARSI histological score. Thus, in rat experimental OA, the OARSI score could be partially predicted by the C2C/CPII ratio as a serum biomarker of OA., (Copyright © 2013 Orthopaedic Research Society.)

To measure the evolution of the serum levels of specific Osteoarthritis (OA) biomarker, Coll2-1 and Coll2-1 NO₂ in knee osteoarthritic patients after viscosupplementation (VS). Fifty-one patients with unilateral symptomatic knee were recruited for this prospective open label study. They received three intra-articular injections of 2 ml of hyaluronic acid (Hylan GF-20) and were followed for 3 months. Walking pain was evaluated and serum samples were taken at each visit. Coll2-1 and Coll2-1 NO₂ were measured in the serum using specific immunoassays. Variations over time of each parameter and predictive factor of response were studied. Forty-five patients were analyzed. The serum concentrations of Coll2-1 and Coll2-1 NO₂ were significantly higher in KL III/IV patients compared to KL I/II patients at baseline and decreased systematically over time after VS. Its effect was ever more pronounced in patients with KL III/IV. The serum concentration of Coll2-1 was significantly lower at baseline in responders than in non-responders. This study suggests a rapid slowdown of type II collagen degradation and joint inflammation after VS with Hylan G-20 and gives additional information for the validation of accurate biomarkers for OA. The serum level of Coll2-1 appeared to be a predictive factor for response to treatment., (Copyright © 2013 Orthopaedic Research Society.)

The aim of the study was to detect differences in serum levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), cartilage oligomeric matrix protein (COMP), type II collagen (CTX-II) between patients with Kashin-Beck disease (KBD) or osteoarthritis (OA) and to assess the correlation between these differences with the clinical grade of KBD. A total of one hundred fifty adult serum samples were collected; these samples belonged to the KBD group (n = 64), the OA group in KBD-prevalent areas (n = 47) and a healthy control group in non-KBD area (n = 39). Serum levels of TNF-α, IL-1β, COMP, and CTX-II were determined by a sandwich enzyme-linked immunosorbent assay, and the results were compared among the 3 groups (KBD/OA/normal) and between the different grades of KBD as well. The serum levels of IL-1β, TNF-α, COMP, and CTX-II were significantly higher in the KBD and OA group than the healthy adult group (P < 0.001), and TNF-α and IL-1β levels in the KBD group were similar to the OA group (for TNF-α, 14.38 ± 7.42 pg/ml vs. 12.61 ± 4.00 pg/ml, respectively, [P = 0.29]; for IL-1β, 141.53 ± 71.35 pg/ml vs. 135.61 ± 68.60 pg/ml, respectively, [P = 0.63]). However, the COMP level was significantly lower and the CTX-II level was higher in the KBD group than in the OA group (for COMP, 7.03 ± 3.11 ng/ml vs. 9.20 ± 3.51 ng/ml, respectively, [P = 0.003]; for CTX-II, 2.23 ± 0.79 ng/ml vs. 1.80 ± 0.87 ng/ml, respectively, [P = 0.026]). Moreover, no significant correlations were found between clinical grade and serum levels of TNF-α, IL-1β, COMP, and CTX-II for the 3 grades of KBD patients (P = 0.645, 0.481, 0.832, and 0.270, respectively). This study showed that serum levels of COMP in KBD patients decreased and CTX-II levels increased compared with the levels in OA patients, but TNF-α and IL-1β levels in KBD and OA group were similar. In addition, increased serum levels of TNF-α, IL-1β, COMP, and CTX-II were not associated with the KBD grade.

Objective: Erosive osteoarthritis of the hand (EHOA) is thought to be an aggressive variant of hand osteoarthritis (HOA) characterised by prominent local inflammation and radiographic aspects of bone erosions in interphalangeal (IP) joints. However, rare studies have until now investigated the value of biomarkers in these patients. Thus, we determined Coll2-1, a marker of type II collagen denaturation, its nitrated form (Coll2-1NO2) and myeloperoxidase (MPO) levels in serum of patients with EHOA vs non-EHOA and subsequently evaluated their relationships with disease indices of severity and activity., Methods: Coll2-1, Coll2-1NO2 and MPO were measured using specific immunoassays in 82 patients, 57 with EHOA, all females, median age 59 (41-74 yrs) and 20 with non-EHOA, all females, median age 55 (43-73 yrs), fulfilling the American College of Rheumatology (ACR) criteria for hand OA. EHOA was characterized by the presence of at least one central bone erosion on radiograph in the IP joints. Patients were also evaluated for disease duration, number of affected (swollen and painful or tender) joints, radiographic score (RS) by Kallman scale and high sensitivity C-reactive protein (hsCRP)., Results: Serum levels of MPO were higher in EHOA (230.0 ± 152.1 ng/ml) than in non-EHOA (160.2 ± 111.5 ng/ml, P=0.037). Coll2-1NO2 levels trended towards an elevation in EHOA compared non-EHOA (0.40 ± 0.86 vs 0.22 ± 0.14 nmol/l, P=0.06), while Coll2-1 levels were not different. Correlations were found for disease duration and both MPO (R(2)=0.48, P=0.001) and Coll2-1NO2 (R(2)=0.73, P=0.01) after the splitting of the population in subgroups according to a cut off value above the 50th percentile. A correlation was found between hsCRP and MPO (R(2)=0.57, P=0.01)., Conclusions: This study clearly demonstrates an elevation of some serum biomarkers in EHOA, in comparison with non-EHOA. In particular, MPO, hsCRP and the ratio Coll2-1NO2/Coll2-1 discriminated the two subsets of hand osteoarthritis (HOA), and a trend was also observed for Coll2-1NO2. These data suggest that these biomarkers could be helpful for the diagnosis of EHOA., (Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Objective: To investigate the immune-modulated effects of decoy receptor 3 (DCR3) in an experimental model of rheumatoid arthritis (RA)., Methods: We delivered DCR3 plasmid into collagen-induced arthritis (CIA) mice using the hydrodynamic method and evaluated the serum level of DCR3 protein by ELISA. After immunization, we assessed disease severity of arthritis incidence, arthritis scores, paw thickness, and means of arthritic limbs, and used hematoxylin and eosin staining to observe synovial hyperplasia. We analyzed numbers of murine splenocytes and inguinal lymphocyte cells, cell populations, and serum proinflammatory cytokines by flow cytometry. We investigated B cell proliferation by carboxyfluorescein succinimidyl ester assay. We evaluated serum levels of total IgG2a and type II collagen-specific IgG and IgG2a using ELISA., Results: DCR3 expression in sera significantly attenuated disease severity in CIA mice. We found that DCR3 inhibited the volume of inguinal lymph nodes, numbers of CD19+ B cells, and populations of interferon-γ, interleukin 4 (IL-4), IL-17A, and Foxp3-producing CD4+ T cell in vivo. We found that DCR3 inhibited Pam3CSK4 (Toll-like receptor 1/2 ligand)-induced B220+ B cell proliferation in vitro. DCR3 treatment reduced the serum level of IL-6, total IgG2a, and CII-specific IgG2a antibody., Conclusion: We postulated that the protective effects of DCR3 in CIA resulted from modulation of the immune system by maintaining the B/T cell balance and decreasing lymphocyte expansion. We suggest DCR3 as a prophylactic and potential therapeutic agent in the treatment of RA.

IL-10 producing regulatory type 1 (Tr1) cells represents a subpopulation of CD4+ regulatory cells able to prevent in vitro bystander T-cell proliferation and to inhibit a wide range of inflammatory diseases in mice. Our aim was to evaluate the frequency and function of joint specific Tr1 cells in the peripheral blood of severe Rheumatoid Arthritis (RA) patients. The collagen II protein was chosen to isolate Tr1 cells specific for a joint antigen. We successfully isolated Tr1 clones from 9 out of 11 RA patients. We showed that cells from patients display the same phenotype and surface marker regulation as previously shown for human Tr1 cells, characterized by expression of markers of regulation (FoxP3, CD25) at the activated but not at the resting state. Importantly, cells from patients showed Tr1 cytokine secretion (IL-10 and IFN-γ) and immunosuppressive action on bystander T cell proliferation. Based on these results, we demonstrated that collagen II specific Tr1 cells can be isolated from the blood of severe refractory patients and that these cells are not altered in their phenotype and function., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Objectives: In joint degenerative diseases, the collagens are degraded by matrix metalloproteinases and protein fragments are released to serum as potential biomarkers., Methods: A collagen type II specific neoepitope, CIIM, was identified (…RDGAAG(1053)) by mass spectrometry. Two ELISAs against the neoepitope were developed. CIIM was measured in cartilage explants in the presence or absence of protease inhibitors. CIIM was measured in OA synovial fluid (n=51) and serum (n=156). Knee OA was graded by standard Kellgren-Lawrence (KL) score., Results: The ELISAs showed good technical performance; CV%, <13%. CIIM release from cartilage explants was blocked by the MMP inhibitor. CIIM was detected in synovial fluid. Furthermore, serum CIIM levels were significantly higher (P<0.05) in those individuals with mild or severe OA than in those with no OA., Conclusion: We developed a new biomarker for joint degenerative diseases, which we demonstrated was derived from MMP-degraded type II collagen., (Copyright © 2011 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)