Biomarkers of cartilage and surrounding joint tissue

Baseline serum levels of cross-linked carboxy-terminal telopeptide of type I collagen predict abatacept treatment response in methotrexate-naive, anticitrullinated protein antibody-positive patients with early rheumatoid arthritis

OBJECTIVE

To investigate correlations between biomarkers of bone remodelling and extracellular matrix turnover with baseline disease activity and treatment response in patients with early rheumatoid arthritis (RA).

METHODS

Assessing Very Early Rheumatoid arthritis Treatment-2 (AVERT-2; NCT02504268) included disease-modifying antirheumatic drug-naive, anti-citrullinated protein antibody (ACPA)-positive patients randomised to weekly subcutaneous abatacept+methotrexate (MTX) or abatacept placebo+MTX for 56 weeks. This post hoc exploratory subanalysis assessed the association between baseline disease activity and eight biomarkers (Spearman's correlation coefficient), and whether baseline biomarkers (continuous or categorical variables) could predict treatment response at weeks 24 and 52 (logistic regression).

RESULTS

Patient characteristics were similar between overall (n=752) and biomarker subgroup (n=535) populations and across treatments. At baseline, neoepitopes of matrix metalloproteinase-mediated degradation products of types III and IV collagen and of C reactive protein (CRP) showed the greatest correlations with disease activity; cross-linked carboxy-terminal telopeptide of type I collagen (CTX-I) showed weak correlation. Only CTX-I predicted treatment response; baseline CTX-I levels were significantly associated with achieving Simplified Disease Activity Index remission and Disease Activity Score in 28 joints (DAS28 (CRP)) <2.6 (weeks 24 and 52), and American College of Rheumatology 70 response (week 52), in patients treated with abatacept+MTX but not abatacept placebo+MTX. CTX-I predicted significant differential response between arms for DAS28 (CRP) <2.6 (week 24). Treatment differences were greater for abatacept+MTX in patients with medium/high versus low baseline CTX-I.

CONCLUSION

In MTX-naive, ACPA-positive patients with early RA, baseline CTX-I predicted treatment response to abatacept+MTX but not abatacept placebo+MTX.

Blood and urine biomarkers in osteoarthritis - an update on cartilage associated type II collagen and aggrecan markers

PURPOSE OF REVIEW

Osteoarthritis (OA) is a painful disease for which drug development has proven difficult. One major reason for this is the heterogeneity of the disease and the current lack of operationalized means to distinguish various disease endotypes (molecular subtypes). Biomarkers measured in blood or urine, reflecting joint tissue turnover, have been developed and tested during the last decades. In this narrative review, we provide highlights on biomarkers derived from the two most studied and abundant cartilage proteins - type II collagen and aggrecan.

RECENT FINDINGS

Multiple biomarkers assessing type II collagen degradation and formation, and aggrecan turnover have been developed. Several markers, such as uCTX-II, have been validated for their association with disease severity and prognosis, as well as pharmacodynamically used to describe the mode of action and efficacy of drugs in development. There is a great need for biomarkers for subdividing patients (i.e., endotyping) and recent scientific advances have not yet come closer to achieving this goal.

SUMMARY

There is strong support for using biomarkers for understanding OA, reflecting degradation and formation of the joint tissues, focused on type II collagen and aggrecan. There is still a lack of in vitro diagnostics, in all contexts of use.

Osteoarthritis: Current Molecular Biomarkers and the Way Forward

The ultimate hope of researchers and patients is a pathway to development of treatments for osteoarthritis to modify the disease process in addition to the symptoms. However, development of disease modifying drugs requires objective endpoints such as measures of joint structure, joint tissue homeostasis and/or joint survival-measures such as provided by imaging biomarkers, molecular biomarkers and joint replacement frequency, respectively. Although biomarkers supporting investigational drug use and drug approval include surrogate endpoints that may not necessarily reflect or directly correlate with the clinical outcome of interest, a formal biomarker qualification process currently exists that is a rigorous three stage process that yields biomarker approvals (or denials) for specific contexts of use. From a cost perspective, biochemical biomarkers are the 'ones to beat'; however, even well-validated biomarkers may not cross the translation gaps for eventual use in healthcare unless they offer an advantage in terms of cost per quality adjusted life year. This review summarizes the case FOR and AGAINST biomarkers in drug development and highlights the current data for a subset of biomarkers in the osteoarthritis research field informing on cartilage homeostasis, joint inflammation and altered subchondral bone remodeling.

Considerations for understanding protein measurements: Identification of formation, degradation and more pathological relevant epitopes

OBJECTIVES

There is a need for precision medicine and an unspoken promise of an optimal approach for identification of the right patients for value-based medicine based on big data. However, there may be a misconception that measurement of proteins is more valuable than measurement of fewer selected biomarkers. In population-based research, variation may be somewhat eliminated by quantity. However, this fascination of numbers may limit the attention to and understanding of the single. This review highlights that protein measurements (with collagens as examples) may mean different things depending on the targeted epitope - formation or degradation of tissues, and even signaling potential of proteins.

DESIGN AND METHODS

PubMed was searched for collagen, neo-epitope, biomarkers.

RESULTS

Ample examples of assays with specific epitopes, either pathological such as HbA1c, or domain specific such as pro-peptides, which total protein arrays would not have identified were evident.

CONCLUSIONS

We suggest that big data may be considered as the funnel of data points, in which most important parameters will be selected. If the technical precision is low or the biological accuracy is limited, and we include suboptimal quality of biomarkers, disguised as big data, we may not be able to fulfill the promise of helping patients searching for the optimal treatment. Alternatively, if the technical precision of the total protein quantification is high, but we miss the functional domains with the most considerable biological meaning, we miss the most important and valuable information of a given protein. This review highlights that measurements of the same protein in different ways may provide completely different meanings. We need to understand the pathological importance of each epitope quantified to maximize protein measurements.

Type I collagen scaffold with WNT5A plasmid for in situ cartilage tissue engineering

BACKGROUND

Cartilage tissue lacks the ability to heal. Cartilage tissue engineering using cell-free scaffolds has been increasingly used in recent years.

OBJECTIVE

This study describes the use of a type I collagen scaffold combined with WNT5A plasmid to promote chondrocyte proliferation and differentiation in a rabbit osteochondral defect model.

METHODS

Type I collagen was extracted and fabricated into a collagen scaffold. To improve gene transfection efficiency, a cationic chitosan derivative N,N,N-trimethyl chitosan chloride (TMC) vector was used. A solution of TMC/WNT5A complexes was adsorbed to the collagen scaffold to prepare a WNT5A scaffold. Osteochondral defects were created in the femoral condyles of rabbits. The rabbits were divided into defect, scaffold, and scaffold with WNT5A groups. At 6 and 12 weeks after creation of the osteochondral defects, samples were collected from all groups for macroscopic observation and gene expression analysis.

RESULTS

Samples from the defect group exhibited incomplete cartilage repair, while those from the scaffold and scaffold with WNT5A groups exhibited "preliminary cartilage" covering the defect. Cartilage regeneration was superior in the scaffold with WNT5A group compared to the scaffold group. Safranin O staining revealed more proteoglycans in the scaffold and scaffold with WNT5A groups compared to the defect group. The expression levels of aggrecan, collagen type II, and SOX9 genes were significantly higher in the scaffold with WNT5A group compared to the other two groups.

CONCLUSIONS

Type I collagen scaffold showed effective adsorption and guided the three-dimensional arrangement of stem cells. WNT5A plasmid promoted cartilage repair by stimulating the expression of aggrecan, type II collagen, and SOX9 genes and proteins, as well as inhibiting cartilage hypertrophy.

The Janus kinase 1/2 inhibitor baricitinib reduces biomarkers of joint destruction in moderate to severe rheumatoid arthritis

Background

Tissue released blood-based biomarkers can provide insight into drug mode of action and response. To understand the changes in extracellular matrix turnover, we analyzed biomarkers associated with joint tissue turnover from a phase 3, randomized, placebo-controlled study of baricitinib in patients with active rheumatoid arthritis (RA).

Methods

Serum biomarkers associated with synovial inflammation (C1M, C3M, and C4M), cartilage degradation (C2M), bone resorption (CTX-I), and bone formation (osteocalcin) were analyzed at baseline, and weeks 4 and 12, from a subgroup of patients (n = 240) randomized to placebo or 2-mg or 4-mg baricitinib (RA-BUILD, NCT01721057). Mixed-model repeated measure was used to identify biomarkers altered by baricitinib. The relationship between changes in biomarkers and clinical measures was evaluated using correlation analysis.

Results

Treatment arms were well balanced for baseline biomarkers, demographics, and disease activity. At week 4, baricitinib 4-mg significantly reduced C1M from baseline by 21% compared to placebo (p < 0.01); suppression was sustained at week 12 (27%, p < 0.001). Baricitinib 4-mg reduced C3M and C4M at week 4 by 14% and 12% compared to placebo, respectively (p < 0.001); they remained reduced by 16% and 11% at week 12 (p < 0.001). In a pooled analysis including all treatment arms, patients with the largest reduction (upper 25% quartile) in C1M, C3M, and C4M by week 12 had significantly greater clinical improvement in the Simplified Disease Activity Index at week 12 compared to patients with the smallest reduction (lowest 25% quartile).

Conclusion

Baricitinib treatment resulted in reduced circulating biomarkers associated with joint tissue destruction as well as concomitant RA clinical improvement.

Trial registration

ClinicalTrials.gov NCT01721057; date of registration: November 1, 2012

Identification of heterogenous treatment response trajectories to anti-IL6 receptor treatment in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory disease with fluctuating course of progression. Despite substantial improvement in treatments in recent years, treatment response is still not guaranteed. The aim of this study was to identify variation in Disease Activity Score 28 (DAS28) of RA patients in response to Tocilizumab, and to investigate both molecular and clinical factors influencing response. Clinical and biochemical data for 485 RA patients receiving Tocilizumab in combination with methotrexate were extracted from the LITHE phase III clinical study (NCT00106535), and post-hoc analysis conducted. Latent class mixed models were used to identify statistically distinct trajectories of DAS28 after the initiation of treatment. Biomarker measurements were then analysed cross-sectionally and temporally, to characterise patients by serological biomarkers and clinical factors. We identified three distinct trajectories of drug response: class 1 (n = 85, 17.5%), class 2 (n = 338, 69.7%) and class 3 (n = 62, 12.8%). All groups started with high DAS28 on average (DAS28 > 5.1). Class 1 showed the least reduction in DAS28, with significantly more patients seeking escape therapy (p < 0.001). Class 3 showed significantly higher rates of improvement in DAS28, with 58.1% achieving ACR response levels compared to 2.4% in class 1 (p < 0.0001). Biomarkers of inflammation, MMP-3, CRP, C1M, showed greater reduction in class 3 compared to the other classes. Identification of more homogenous patient sub-populations of drug response may allow for more targeted therapeutic treatment regimens and a better understanding of disease aetiology.

Collagen biology and non-invasive biomarkers of liver fibrosis

There is an unmet need for high-quality liquid biomarkers that can safely and reproducibly predict the stage of fibrosis and the outcomes of chronic liver disease (CLD). The requirement for such markers has intensified because of the high global prevalence of diseases such as non-alcoholic fatty liver disease (NAFLD). In particular, there is a need for diagnostic and prognostic tools, as well as predictive biomarkers that reflect the efficacy of interventions, as described by the BEST criteria (Biomarkers, EndpointS, and other Tools Resource). This review covers the various liver collagens, their functional role in tissue homeostasis and delineates the common nomenclature for biomarkers based on BEST criteria. It addresses the common confounders affecting serological biomarkers, and describes defined collagen epitope biomarkers that originate from the dynamic processes of extracellular matrix (ECM) remodelling during liver injury.

Serological biomarker profiles of rapidly progressive osteoarthritis in tanezumab-treated patients

There is a need for efficacious and safe pain treatments for OA (osteoarthritis). The nerve growth factor (NGF) antibody tanezumab is associated with high efficacy, but when combined with chronic NSAID treatment shows an increased risk of rapidly progressive osteoarthritis (RPOA) in a small group of patients.

AIM

The aim of this study was to phenotype with biochemical biomarkers of bone, cartilage, soft tissue, synovial metabolism OA patients who are at risk of developing RPOA type-2, for both limited and chronic NSAIDs users.

MATERIAL AND METHODS

The dataset consisted of OA patients participating in tanezumab trials who used NSAIDs <90 days (limited NSAID users) or chronic users (NSAIDs ≥90 days) over an average 10 month period. Biomarker data were available for 47 cases (RPOA type-2) and 92 controls. Non-linear and linear multivariable predictive models were developed.

RESULTS

By use of two biomarkers at baseline the receiver operating characteristic (ROC) curve area for RPOA type-2 in limited NSAID users was 71%, [CI] (60-83%). OA subjects with this biomarker phenotype had 8-fold higher confidence interval [CI][(2-33)] relative risk of developing RPOA type-2 as compared to OA patients without this phenotype. The AUC of the model in chronic NSAIDs users based on 5 biomarkers was 78%, [CI](69-88%), with 4-fold [CI (2-6)] relative risk of developing RPOA type-2.

CONCLUSION

In this hypothesis generating and exploratory study, we identified combinations of biomarkers associated with OA patients who develop RPOA type-2, which may be related to the pathology of the RPOA type-2 joint.

Tissue metabolite of type I collagen, C1M, and CRP predicts structural progression of rheumatoid arthritis

Background

Biomarkers of rheumatoid arthritis (RA) disease activity typically measure inflammation or autoimmunity (e.g. CRP, RF). C1M and C3M, metabolites of type I and III collagen, are markers reflecting tissue metabolism. These markers have been documented to provide additional prognostic and predictive value compared to commonly used biomarkers. We investigated the relationship of high serum levels of C1M or C3M to radiographic progression, and benchmarked them to CRP and RF.

Methods

Placebo treated patients of the OSK1, 2 and 3 studies (Phase III clinical trials testing efficacy of fostamatinib) with baseline serum biomarkers C1M, C3M, CRP and RF were included (n_BL = 474). Van der Heijde mTSS was calculated at baseline and 24-week (n₂₄ = 261). Progression was defined as moderate or rapid by ΔmTSS ≥0.5 or ≥ 5 units/year. Patients were divided into subgroups; low (L), high (H) or very high (V) C1M, C3M and CRP, or RF negative, positive and high positive. Difference in clinical parameters were analyzed by Mann-Whitney or χ²tests, and modelling for prediction of progression by logistic regression including covariates (age, gender, BMI, and clinical assessment scores).

Results

Levels of C1M, C3M, CRP and RF were significantly (p < 0.05) associated with measures of disease activity and mTSS at baseline. For prognostic measures, there were 2.5 and 4-fold as many rapid progressors in the C1M_H and CRP_H (p < 0.05), and in the C1M_V and CRP_V groups (p < 0.001) compared C1M_L and CRP_L, respectively. C1M and CRP performed similarly in the predictive analysis, where high levels predicted moderate and rapid progression with odds ratio of 2.1 to 3.8 and 3.7 to 13.1 after adjustment for covariates. C3M and RF did not provide prognostic value alone.

Discussion

Serum C1M and CRP showed prognostic value and may be tools for enrichment of clinical trials with structural progressor. The two markers reflect two different aspect of disease pathogenesis (tissue turnover vs. inflammation), thus may provide individual and supplementary information.

Electronic supplementary material

The online version of this article (10.1186/s41927-019-0052-0) contains supplementary material, which is available to authorized users.

Osteochondral repair using an acellular dermal matrix-pilot in vivo study in a rabbit osteochondral defect model

The aim of this pilot project was to introduce a novel use of acellular dermal matrix (ADM) in combination with infrapatellar fat pad mesenchymal stromal cells (IPFP-MSCs) to effect repair in a rabbit osteochondral defect model. ADM, in a range of surgical procedures, has been shown to promote remodelling of tissue at the site of implantation. Rabbit-derived ADM (rabADM) was prepared from the skin of donor rabbits. Autologous IPFP-MSCs were obtained at the time of knee surgery. Osteochondral defects (4 mm cartilage outer/2 mm central bone defect) were drilled into distal femoral condyles of 12 New Zealand White rabbits. Treatments groups: (i) defect only; (ii) rabADM alone; (iii) IPFP-MSCs alone; and (iv) rabADM with IPFP-MSCs. Condyles were harvested at 12 weeks, and analyzed using histology, immunohistochemistry (types I and II collagen) and histomorphometry to evaluate osteochondral repair. The rabADM only group achieved the highest ratio of type II to non-type II collagen (77.3%) using areal measures (similar to normal cartilage), which indicated a higher quality of cartilage repair. The addition of IPFP-MSCs, with or without rabADM, formed a fibrous collagen cap above the lesion site not seen with rabADM alone. Macroscopically, there was no joint erosion, inflammation, swelling or deformity, and all animals maintained full range of motion.

CONCLUSIONS

RabADM alone resulted in neocartilage formation similar to native cartilage. IPFP-MSCs limited osteochondral repair and contributed to fibrosis, even in combination with the rabADM. Further studies using ADM for osteochondral repair are warranted in a more appropriate pre-clinical model of osteochondral repair. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1919-1928, 2018.

Fragments generated upon extracellular matrix remodeling: Biological regulators and potential drugs

The remodeling of the extracellular matrix (ECM) by several protease families releases a number of bioactive fragments, which regulate numerous biological processes such as autophagy, angiogenesis, adipogenesis, fibrosis, tumor growth, metastasis and wound healing. We review here the proteases which generate bioactive ECM fragments, their ECM substrates, the major bioactive ECM fragments, together with their biological properties and their receptors. The translation of ECM fragments into drugs is challenging and would take advantage of an integrative approach to optimize the design of pre-clinical and clinical studies. This could be done by building the contextualized interaction network of the ECM fragment repertoire including their parent proteins, remodeling proteinases, and their receptors, and by using mathematical disease models.

Identification of serological biomarker profiles associated with total joint replacement in osteoarthritis patients

OBJECTIVE

Establish a biomarker panel associated with all-cause total joint replacement (TJR) through identification of patients with osteoarthritis (OA) who do or do not progress to TJR and investigate effects of nonsteroidal anti-inflammatory drugs (NSAIDs).

DESIGN

Serum samples from patients enrolled in phase III trials of tanezumab who experienced TJR (n = 174) or matched patients who did not (n = 321) were analyzed for bone, cartilage, soft tissue, and inflammation markers. Classification and Regression Tree (CART) analysis was used to identify biomarker phenotypes associated with TJR.

RESULTS

At baseline, biomarker combinations for patients who did not use NSAIDs before starting tanezumab and used NSAIDs during tanezumab treatment <90 days ("nonNSAID"), identified 77% (95% confidence interval [CI]: 71-84%) of patients who experienced TJR and 77% (95% CI: 65-86%) who did not over a 6-month study period (on average). These biomarker combinations increased odds of identifying patients to remain free of a TJR by 3.3-fold. In patients who used NSAIDs continuously (during screening and ≥90 days during tanezumab treatment), 64% (95% CI: 54-73%) who had TJR and 75% (95% CI: 68-83%) who did not were identified by biomarker combinations different from nonNSAID patients, with an increase in odds of identifying patients to remain free of a TJR by two-fold.

CONCLUSIONS

Although validation on other cohorts is necessary, biomarkers may assist in identifying patients who will need TJR. The profiles suggest NSAID use increases importance of bone metabolism in TJR pathology.

Altered collagen turnover in factor VIII-deficient rats with hemophilic arthropathy identifies potential novel serological biomarkers in hemophilia

Essentials Joint bleeding in hemophilia may induce significant remodeling of the extracellular matrix. Biomarkers of collagen turnover were investigated in a F8-/- rat model of hemophilic arthropathy. Biomarkers of cartilage degradation increased significantly during development of arthropathy. Basement membrane and interstitial matrix turnover changed significantly following hemarthrosis.

SUMMARY

Background Hemophilic arthropathy is a severe complication of hemophilia. It is caused by recurrent bleeding into joint cavities, which leads to synovial inflammation, fibrosis, cartilage degradation and bone remodeling. Extracellular matrix remodeling of affected tissues is a hallmark of these pathological processes. Objectives The aim of this study was to use serological biomarkers of collagen turnover to evaluate extracellular matrix remodeling in a factor VIII-deficient rat model of hemophilic arthropathy. Methods F8-/- rats and wild-type littermate controls were subjected to repeated knee bleeds induced by needle puncture on days 0 and 14. Development of arthropathy was confirmed by histology after termination on day 28. Serum samples were collected at baseline and throughout the study and analyzed for biomarkers of collagen turnover, including collagens of the basement membrane (type IV collagen), the interstitial matrix (collagen types III, V and VI) and cartilage (type II collagen). Results In F8-/- rats, induced knee bleeding and subsequent development of arthropathy caused significant alterations in collagen turnover, measured as changes in serological biomarkers of basement membrane turnover, interstitial matrix turnover and cartilage degradation. Biomarkers of type II collagen degradation correlated significantly with cartilage degradation and degree of arthropathy. Hemophilic rats had a 50% higher turnover of the basement membrane than wild-type littermates at baseline. Conclusions Joint bleeding and hemophilic arthropathy cause changes in turnover of extracellular matrix collagens in hemophilic rats. Biomarkers of collagen turnover may be used to monitor joint bleeding and development of blood-induced joint disease in hemophilia.

Chondrocyte activity is increased in psoriatic arthritis and axial spondyloarthritis

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.