Cartilage oligomeric matrix protein, C-terminal cross-linking telopeptide of type II collagen, and matrix metalloproteinase-3 as biomarkers for knee and hip osteoarthritis (OA) diagnosis: a systematic review and meta-analysis

Emerging Technologies and Platforms for the Immunodetection of Multiple Biochemical Markers in Osteoarthritis Research and Therapy

Biomarkers, especially biochemical markers, are important in osteoarthritis (OA) research, clinical trials, and drug development and have potential for more extensive use in therapeutic monitoring. However, they have not yet had any significant impact on disease diagnosis and follow-up in a clinical context. Nevertheless, the development of immunoassays for the detection and measurement of biochemical markers in OA research and therapy is an active area of research and development. The evaluation of biochemical markers representing low-grade inflammation or extracellular matrix turnover may permit OA prognosis and expedite the development of personalized treatment tailored to fit particular disease severities. However, currently detection methods have failed to overcome specific hurdles such as low biochemical marker concentrations, patient-specific variation, and limited utility of single biochemical markers for definitive characterization of disease status. These challenges require new and innovative approaches for development of detection and quantification systems that incorporate clinically relevant biochemical marker panels. Emerging platforms and technologies that are already on the way to implementation in routine diagnostics and monitoring of other diseases could potentially serve as good technological and strategic examples for better assessment of OA. State-of-the-art technologies such as advanced multiplex assays, enhanced immunoassays, and biosensors ensure simultaneous screening of a range of biochemical marker targets, the expansion of detection limits, low costs, and rapid analysis. This paper explores the implementation of such technologies in OA research and therapy. Application of novel immunoassay-based technologies may shed light on poorly understood mechanisms in disease pathogenesis and lead to the development of clinically relevant biochemical marker panels. More sensitive and specific biochemical marker immunodetection will complement imaging biomarkers and ensure evidence-based comparisons of intervention efficacy. We discuss the challenges hindering the development, testing, and implementation of new OA biochemical marker assays utilizing emerging multiplexing technologies and biosensors.

The molecular mechanism study of COMP involved in the articular cartilage damage of Kashin-Beck disease

Aims

Kashin-Beck disease (KBD) is a kind of chronic osteochondropathy, thought to be caused by environmental risk factors such as T-2 toxin. However, the exact aetiology of KBD remains unclear. In this study, we explored the functional relevance and biological mechanism of cartilage oligosaccharide matrix protein (COMP) in the articular cartilage damage of KBD.

Methods

The articular cartilage specimens were collected from five KBD patients and five control subjects for cell culture. The messenger RNA (mRNA) and protein expression levels were detected by quantitative reverse transcription PCR (qRT-PCR) and western blot. The survival rate of C28/I2 chondrocyte cell line was detected by MTT assay after T-2 toxin intervention. The cell viability and mRNA expression levels of apoptosis related genes between COMP-overexpression groups and control groups were examined after cell transfection.

Results

The mRNA and protein expression levels of COMP were significantly lower in KBD chondrocytes than control chondrocytes. After the T-2 toxin intervention, the COMP mRNA expression of C28/I2 chondrocyte reduced and the protein level of COMP in three intervention groups was significantly lower than in the control group. MTT assay showed that the survival rate of COMP overexpression KBD chondrocytes were notably higher than in the blank control group. The mRNA expression levels of Survivin, SOX9, Caspase-3, and type II collagen were also significantly different among COMP overexpression, negative control, and blank control groups.

Conclusion

Our study results confirmed the functional relevance of COMP with KBD. COMP may play an important role in the excessive chondrocytes apoptosis of KBD patients.Cite this article: Bone Joint Res 2020;9(9):578-586.

Setting up distinctive outcome measures for each osteoarthritis phenotype

Osteoarthritis (OA) is an evolving chronic joint disease with a huge global impact. Given the intricate nature of the etiopathogenesis and subsequent high heterogeneity in the clinical course of OA, it is crucial to discriminate between etiopathogenic endotypes and clinical phenotypes, especially in the early stages of the disease. In this sense, we propose that an OA phenotype should be properly assessed with a set of outcome measures including those specifically related to the main underlying pathophysiological mechanisms. Thus, each OA phenotype can be related to different and clinically meaningful outcomes. OA phenotyping would lead to an adequate patient stratification in well-designed clinical trials and the discovery of precise therapeutic approaches. A significant effort will be required in this field in light of inconclusive results of clinical trials of tissue-targeting agents for the treatment of OA.

In vivo protective effects of upper zone of growth plate and cartilage matrix associated protein against cartilage degeneration in a monosodium iodoacetate induced osteoarthritis model

Osteoarthritis (OA) is a degenerative disease affecting the majority of over 65 year old people and characterized by cartilage degeneration, subchondral abnormal changes, and inflammation. Despite the enormous socioeconomic burden caused by OA, currently, there is no effective therapy against it. Upper zone of growth plate and cartilage matrix associated protein (UCMA) is a vitamin K dependent protein and has a critical role in pathophysiological conditions associated with bone and cartilage. However, there is no research on the protective role of intra-articular UCMA treatment in OA pathogenesis. Therefore, we aimed to investigate the potential therapeutic role of UCMA in an in vivo model of OA. We report for the first time that intra-articular UCMA injection ameliorated cartilage degeneration in a monosodium iodoacetate induced OA rat model. Furthermore, the OA-induced activation of nuclear factor kappa B and bone morphogenetic protein 2 signals was attenuated by UCMA. Our results indicated that UCMA decreased cartilage oligomeric matrix protein levels but did not affect interleukin 6, total antioxidant status, and total oxidant status levels in the serum. In conclusion, UCMA exhibited a therapeutic potential in the treatment of OA. This protective effect of UCMA is possibly achieved by reducing the aggrecanase activity and the production of inflammatory cytokines.

Intraosseous injections of platelet rich plasma for knee bone marrow lesions treatment: one year follow-up

PURPOSE

Cartilage lesions are usually accompanied by subchondral bone alterations or bone marrow lesions (BMLs). BML associated with joint degeneration and cartilage lesions are considered to be predictors of rapidly progressing OA. Currently no existing treatment can fully halt OA progression. One of the approaches is an autologous, biological treatment based on the use of platelet rich plasma (PRP) injections. The purpose of this study is to assess the short-term effectiveness of intraosseous PRP injections, within the BML of individuals affected by OA, in ameliorating pain and improving knee functionality.

MATERIALS AND METHODS

The study involved 17 patients with an average age of 41.7 ± 14.3 years old. OA stage was determined using the Kellgren-Lawrence grading system by performing radiographic scanning of the knee joint before surgical intervention. Patients with K-L grade 3 knee joint OA prevailed. Patient OA history varied between one and nine years (average 5.2 ± 4.5 years). Clinical and functional state of the knee were assessed by pain visual analogue scale (VAS) score, the Western Ontario and McMaster Universities Score (WOMAC), and the Knee Injury and Osteoarthritis Outcome Score (KOOS) which were filled out by patients previous to the surgical procedure at one, three, six and 12 months post-operatively. Before surgery, in addition to standard blood tests, serum cartilage oligomeric matrix protein (COMP) levels were tested for all patients.

RESULTS

Evaluation of preliminary results revealed a statistically significant reduction of pain based on the VAS score. A significant improvement was also observed in the patients' WOMAC score and in the overall KOOS score. Serum marker levels were initially elevated in our experimental patient group compared to the same marker in healthy control respondents, and continued to rise one month and three months following surgery, at six and 12 month the level was similar as at three months.

CONCLUSIONS

In our opinion, first COMP increasing can be caused by injection of platelet rich plasma. It is not adequate to interpret this growth in COMP levels as increased osteochondral degeneration. One year follow-up period showed good quality of life improvement, significant pain reduction, and essential MRI changes. The long-term observation of these cohort of patients combined with an analysis of MRI images is still ongoing.

Can urinary CTX-II be a biomarker for knee osteoarthritis?

Background

Early diagnosis of knee osteoarthritis (OA) remains a diagnostic challenge. Urinary C-terminal cross-linked telopeptide of type II collagen (urinary CTX-II) is one of the potential OA biomarkers. However, conclusive evidence regarding the use of this biomarker as a tool for early diagnosis is still lacking. The purposes of this study were to compare urinary CTX-II levels in patients with knee OA and in healthy controls, to evaluate the correlation between urinary CTX-II levels, radiographic severity of OA, and patient-reported outcomes and to evaluate the effect of age and gender on urinary CTX-II levels in the Asian populations.

Methods

Two groups were studied. The OA group included 78 patients with knee OA aged > 40 years who met the diagnostic criteria for knee OA described by the American College of Rheumatology (ACR). The control group consisted of 51 healthy participants age > 40 years without clinical or radiographic evidence of knee OA. Bilateral knee radiographs were taken and classified according to the Kellgren and Lawrence (KL) grading system. Urinary CTX-II was measured using a competitive ELISA test and Western Ontario and Mcmaster Universities Arthritis Index (WOMAC) was also recorded in all participants.

Results

Urinary CTX-II was significantly higher in the OA group than in the control group (p < 0.001). The severe knee OA group (KL grade 3 and 4) had higher urinary CTX-II levels than mild knee OA group (KL grade 2) but the difference did not reach statistical significance (p = 0.2). There was a moderate correlation between urinary CTX-II levels and KL grades (r = 0.405, p < 0.001) and a weak correlation between urinary CTX-II levels and WOMAC index scores (r = 0.367, p < 0.001). Multiple regression analysis showed that urinary CTX-II was independently associated with KL grades. Whereas age, gender, and WOMAC index had no statistically significant influence on the urinary CTX-II levels.

Conclusions

Patients with knee OA had higher urinary CTX-II levels than healthy controls. Moreover, levels of urinary CTX-II were independently correlated with radiographic severity of knee OA. Age, gender, and patient-reported outcomes exerted no effect on the urinary CTX-II levels.

Level of evidence

Diagnostic Level III.

Serum Cartilage Oligomeric Matrix Protein in Late-Stage Osteoarthritis: Association with Clinical Features, Renal Function, and Cardiovascular Biomarkers

This study aimed to assess associations between serum cartilage oligomeric matrix protein (sCOMP) and phenotypic characteristics in late-stage hip and knee Osteoarthritis (OA) as well as its correlation with further serum markers of possible comorbidities in the Ulm Osteoarthritis Study. Moreover, the prognostic relevance of preoperative sCOMP concentrations for short-term functionality and pain outcomes after hip or knee joint replacement was explored. Preoperative serum samples and detailed information about the health status (i.e., WOMAC scores, Hannover Functionality Status (FFbH)) of 754 OA patients undergoing total joint replacement were included. Spearman rank-correlation coefficients and multiple linear regression models were used to evaluate the relationships between sCOMP, other serum markers, and health outcomes. There was a significant positive association between sCOMP and markers of renal (cystatin C, creatinine, and eGFR) and cardiac (e.g., NT-proBNP) impairment. Since renal failure might cause accumulation of sCOMP, additional adjustment with eGFR was performed. Preoperative sCOMP levels in knee OA but not hip OA patients were positively associated with FFbH, WOMAC function sub-scale and total WOMAC scale as well as the post-operative WOMAC stiffness sub-scale six months after surgery. Our data clearly demonstrate an association between sCOMP and renal function as well as other confounding factors, which should be considered in future biomarker studies.

Multifaceted Protective Role of Glucosamine against Osteoarthritis: Review of Its Molecular Mechanisms

Osteoarthritis (OA) is a joint disease resulting from cartilage degeneration and causing joint pain and stiffness. Glucosamine exerts chondroprotective effects and effectively reduces OA pain and stiffness. This review aims to summarise the mechanism of glucosamine in protecting joint health and preventing OA by conducting a literature search on original articles. Current evidence has revealed that glucosamine exhibits anti-inflammatory effects by reducing the levels of pro-inflammatory factors (such as tumour necrosis factor-alpha, interleukin-1, and interleukin-6) and enhancing the synthesis of proteoglycans that retard cartilage degradation and improve joint function. Additionally, glucosamine improves cellular redox status, reduces OA-mediated oxidative damages, scavenges free radicals, upregulates antioxidant proteins and enzyme levels, inhibits the production of reactive oxygen species, and induces autophagy to delay OA pathogenesis. In conclusion, glucosamine prevents OA and maintains joint health by reducing inflammation, improving the redox status, and inducing autophagy in joints. Further studies are warranted to determine the synergistic effect of glucosamine with other anti-inflammatory and/or antioxidative agents on joint health in humans.

The time course and mechanisms of change in biomarkers of joint metabolism in response to acute exercise and chronic training in physiologic and pathological conditions

PURPOSE

The benefits of exercise across the lifespan and for a wide spectrum of health and diseases are well known. However, there remains less clarity as to the effects of both acute and chronic exercise on joint health. Serum biomarkers of joint metabolism are sensitive to change and have the potential to differentiate between normal and adverse adaptations to acute and chronic load. Therefore, the primary objective of this review is to evaluate how serum biomarkers can inform our understanding of how exercise affects joint metabolism.

METHODS

A comprehensive literature search was completed to identify joint biomarkers previously used to investigate acute and chronic exercise training.

RESULTS

Identified biomarkers included those related to joint cartilage, bone, synovium, synovial fluid, and inflammation. However, current research has largely focused on the response of serum cartilage oligomeric matrix protein (COMP) to acute loading in healthy young individuals. Studies demonstrate how acute loading transiently increases serum COMP (i.e., cartilage metabolism), which is mostly dependent on the duration of exercise. This response does not appear to be associated with any lasting deleterious changes, cartilage degradation, or osteoarthritis.

CONCLUSION

Several promising biomarkers for assessing joint metabolism exist and may in future enhance our understanding of the physiological response to acute and chronic exercise. Defining 'normal' and 'abnormal' biomarker responses to exercise and methodological standardisation would greatly improve the potential of research in this area to understand mechanisms and inform practice.

Notch1-ADAM8 positive feed-back loop regulates the degradation of chondrogenic extracellular matrix and osteoarthritis progression

Background

Osteoarthritis (OA) is one of the most prevalent joint disease, and there are still no effective therapeutic agents or clinical methods for the cure of this disease to date. The degradation of cartilage extracellular matrix (ECM) is a major cause of OA.

Method

IL-1β was used to induce chondrogenic degradation. Q-PCR and Western blotting were used to detect mRNA and protein level, respectively. ELISA was used to detect the secreted TNF-α and IL-6 level. Immunofluorescence was used to detect the protein level of Aggrecan, Collagen II and ki67. TUNEL and flow cytometry were used to examine cell apoptosis of chondrocytes. ChIP and luciferase assay were used to study molecular gene regulation. Osteoarthritic animal model and Safranin-O staining were used to determine the in vivo OA phenotype.

Results

The expression of ADAM8 was up-regulated in osteoarthritic chondrocytes. Knockdown of ADAM8 suppressed the OA phenotype in the in vitro OA cell model. ADAM8 regulated OA progression through the activation of EGFR/ERK/NF-κB signaling pathway. Inhibition of Notch signaling suppressed OA phenotype in the in vitro OA cell model. Notch signaling regulated the gene expression of ADAM8 directly via Hes1. Notch1-ADAM8 positive feedback loop promoted the progression of OA in vivo.

Conclusion

Notch1-ADAM8 feed-back loop regulates the degradation of chondrogenic extracellular matrix and osteoarthritis progression.

Role of SREBP2 gene polymorphism on knee osteoarthritis in the South Indian Hyderabad Population: A hospital based study with G595C variant

Introduction

Osteoarthritis (OA) is a multifactorial disease with genetic factors playing a crucial role, and it has been associated with a family history of obesity. G595C polymorphism in the sterol regulatory element-binding protein 2 (SREBP2) gene has demonstrated an association with knee osteoarthritis (KOA) patients. However, this polymorphism has been never explored in an Indian population. Hence, the current study aimed to examine whether G595C (rs2228314) polymorphism in SREBP2 gene was associated with KOA susceptibility in the South Indian Hyderabad population.

Methods

G595C polymorphism was genotyped with 200 KOA cases and 200 healthy controls using polymerase chain reaction-restriction fragment length polymorphism analysis.

Results

A significant association was observed between age, body mass index (BMI), and family histories in KOA cases and controls (p < 0.05). The current allele (C vs G; OR-2.8 [95%CI = 2.1-3.7]; p < 0.0001) and genotype analysis confirms the significant association with (GC + CC vs GG; OR-3.5 [95%CI = 2.3-5.3]; p < 0.0001 & GC vs GG + CC; OR-1.7 [95%CI = 1.0-2.9]; p = 0.02) KOA vs. control subjects. On stratification analysis, genotype CC and C allele were associated with KOA. Gender association failed to demonstrate positive genotype frequencies (p > 0.05). Multifactor-dimensionality reduction (MDR) analysis showed a positive association with BMI and G595C genotypes (p < 0.05); 51% of the homozygous variant CC genotypes were present in obesity subjects.

Conclusion

In conclusion, our findings suggest that G595C polymorphism in SREBP2 gene is associated with KOA in the South Indian Hyderabad population and presents scope for further investigation of the gene's function in KOA.

A Novel Rat Model of Patellofemoral Osteoarthritis Due to Patella Baja, or Low-Lying Patella

Background

Patella baja, or patella infera, consists of a low-lying patella that results in a limited range of motion, joint pain, and crepitations. Patellofemoral joint osteoarthritis (PFJOA) is a subtype OA of the knee. This study aimed to develop a reproducible and reliable rat model of PFJOA.

Material/Methods

Three-month-old female Sprague-Dawley rats (n=24) included a baseline group (n=8) that were euthanized at the beginning of the study. The sham group (n=8), and the patella ligament shortening (PLS) group (n=8) were euthanized and evaluated at ten weeks. The PLS model group (n=8) underwent insertion of a Kirschner wire under the patella tendon to induce patella baja. At ten weeks, the sham group and the PLS group were compared using X-ray imaging, macroscopic appearance, histology, immunohistochemistry, TUNEL staining for apoptosis, and micro-computed tomography (micro-CT). The patella height was determined using the modified Insall-Salvati (MIS) ratio.

Results

The establishment of the rat model of patella baja in the PLS group at ten weeks was confirmed by X-ray. In the PLS group, patella volume, sagittal length, and cross-sectional area were significantly increased compared with the sham group. The PFJ showed typical lesions of OA, confirmed macroscopically and histologically. Compared with the sham group, in the rat model of PFJOA, there was increased cell apoptosis, and immunohistochemistry showed increased expression of biomarkers of osteoarthritis, compared with the sham group.

Conclusions

A rat model of PFJOA was developed that was confirmed by changes in cartilage and subchondral bone.