Hyaluronic acid levels may have predictive value for the progression of knee osteoarthritis

Genicular Artery Embolization for Treatment of Knee Osteoarthritis: Interim Analysis of a Prospective Pilot Trial Including Effect on Serum Osteoarthritis-Associated Biomarkers

PURPOSE

To characterize the safety, efficacy, and potential role of genicular artery embolization (GAE) as a disease-modifying treatment for symptomatic knee osteoarthritis (OA).

MATERIALS AND METHODS

This is an interim analysis of a prospective, single-arm clinical trial of patients with symptomatic knee OA who failed conservative therapy for greater than 3 months. Sixteen patients who underwent GAE using 250-μm microspheres and had at least 1 month of follow-up were included. Six patients completed the 12-month follow-up, and 10 patients remain enrolled. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was evaluated at baseline and at 1, 3, and 12 months. Serum and plasma samples were collected for biomarker analysis. The primary end point was the percentage of patients who achieved the minimal clinically important difference (MCID) for WOMAC pain score at 12 months. Baseline and follow-up outcomes were analyzed using the Wilcoxon matched-pairs signed-rank test.

RESULTS

Technical success of the procedure was 100%, with no major adverse events. The MCID was achieved in 5 of the 6 (83%) patients at 12 months. The mean WOMAC pain score decreased from 8.6 ± 2.7 at baseline to 4.9 ± 2.7 (P = .001), 4.4 ± 2.8 (P < .001), and 4.7 ± 2.7 (P = .094) at 1, 3, and 12 months, respectively. There was a statistically significant decrease in nerve growth factor (NGF) levels at 12 months. The remaining 8 biomarkers showed no significant change at 12 months.

CONCLUSIONS

GAE is a safe and efficacious treatment for symptomatic knee OA. Decreased NGF levels after GAE may contribute to pain reduction and slowing of cartilage degeneration.

Soluble biological markers in osteoarthritis

In recent years, markers research has focused on the structural components of cartilage matrix. Specifically, a second generation of degradation markers has been developed against type II collagen neoepitopes generated by specific enzymes. A particular effort has been made to measure the degradation of minor collagens III and X of the cartilage matrix. However, because clinical data, including longitudinal controlled studies, are very scarce, it remains unclear whether they will be useful as an alternative to or in combination with current more established collagen biological markers to assess patients with osteoarthritis (OA). In addition, new approaches using high-throughput technologies allowed to detect new types of markers and improve the knowledge about the metabolic changes linked to OA. The relative advances coming from phenotype research are a first attempt to classify the heterogeneity of OA, and several markers could improve the phenotype characterization. These phenotypes could improve the selection of patients in clinical trials limiting the size of the studies by selecting patients with OA characteristics corresponding to the metabolic pathway targeted by the molecules evaluated. In addition, the inclusion of rapid progressors only in clinical trials would facilitate the demonstration of efficacy of the investigative drug to reduce joint degradation. The combination of selective biochemical markers appears as a promising and cost-effective approach to fulfill this unmet clinical need. Among the various potential roles of biomarkers in OA, their ability to monitor drug efficacy is probably one of the most important, in association with clinical and imaging parameters. Biochemical markers have the unique property to detect changes in joint tissue metabolism within a few weeks.

Common Biochemical and Magnetic Resonance Imaging Biomarkers of Early Knee Osteoarthritis and of Exercise/Training in Athletes: A Narrative Review

Knee osteoarthritis (OA) is the most common joint disease of the world population. Although considered a disease of old age, OA also affects young individuals and, more specifically among them, those practicing knee-joint-loading sports. Predicting OA at an early stage is crucial but remains a challenge. Biomarkers that can predict early OA development will help in the design of specific therapeutic strategies for individuals and, for athletes, to avoid adverse outcomes due to exercising/training regimens. This review summarizes and compares the current knowledge of fluid and magnetic resonance imaging (MRI) biomarkers common to early knee OA and exercise/training in athletes. A variety of fluid biochemical markers have been proposed to detect knee OA at an early stage; however, few have shown similar behavior between the two studied groups. Moreover, in endurance athletes, they are often contingent on the sport involved. MRI has also demonstrated its ability for early detection of joint structural alterations in both groups. It is currently suggested that for optimal forecasting of early knee structural alterations, both fluid and MRI biomarkers should be analyzed as a panel and/or combined, rather than individually.

Comparison of patient-reported outcomes of treatment with low- and intermediate molecular weight hyaluronic acid in Japanese patients with symptomatic knee osteoarthritis: A prospective, randomized, single-blind trial

Objectives

The objective of this study was to compare the clinical outcomes of treatment with low- or intermediate-molecular-weight hyaluronic acid (HA) in patients with knee osteoarthritis (OA).

Methods

In total, 59 patients with OA who fulfilled the criteria of the American College of Rheumatology for OA were enrolled. Patients were randomly assigned in a 1:1 ratio to the low- or intermediate-molecular-weight HA group. An intraarticular injection of HA into the knee joint was performed five times per week. The visual analog scale for pain (pain VAS) and Japanese Knee Osteoarthritis Measure (JKOM) score were analyzed at baseline and week 6 to assess the outcomes.

Results

Pain VAS and JKOM score were significantly improved in both groups. At follow-up, there were no significant between-group differences in pain VAS or total JKOM score. Moreover, reduction in pain VAS and JKOM score was not significantly different between the two groups.

Conclusions

Both low- and intermediate-molecular-weight HA have significant efficacy in the first-line treatment of patients with knee OA as indicated by patient-reported outcomes. However, there does not appear to be any difference between the efficacy of low- and intermediate-molecular-weight HA as indicated by the JKOM score. We believe that the results of this study provide important insights into the clinical management of Japanese patients with knee OA.

Biochemical Markers for the Early Identification of Osteoarthritis: Systematic Review and Meta-Analysis

BACKGROUND

There is a desperate need for the reliable detection of osteoarthritis (OA) at the early stage when patients are likely to benefit most from disease interventions. A variety of biochemical markers have been proposed, but their reliability varies among studies.

OBJECTIVE

In this review, we aimed to answer the following questions: (1) are there biochemical markers that are differentially expressed in early OA versus healthy subjects, and (2) if so, what is the diagnostic value of these biomarkers for early OA?

METHODS

Embase, PubMed, and Web of Science were searched to obtain all relevant studies up to March 2018, and studies comparing the biochemical markers between early OA and healthy controls were selected. The Downs and Black checklist was used to assess the risk of bias. Biomarkers that were investigated in five or more different populations were pooled for meta-analysis. A meta-regression analysis was performed to explore possible explanations for the heterogeneity of studies.

RESULT

In total, 26 articles met the criteria for the qualitative synthesis and 17 articles for the final quantitative synthesis. N-terminal crosslinked telopeptide of type I collagen (NTX-I) was the only biomarker found to be differently expressed in patients with early OA versus controls, without significant heterogeneity among studies (I2 = 0%, [Formula: see text] = 1.695, p = 0.792). The meta-regression analysis identified that sample size and affected joint possibly explained the heterogeneity among studies.

CONCLUSION

Although a wide range of biomarkers has been previously investigated in early OA, the diagnostic value of these biomarkers could not be determined because due to a low number of studies regarding any given biomarker. Large prospective and adequately powered studies are therefore required to validate these (and other) biomarkers for identifying early OA.

EULAR recommendations for the use of imaging in the clinical management of peripheral joint osteoarthritis

The increased information provided by modern imaging has led to its more extensive use. Our aim was to develop evidence-based recommendations for the use of imaging in the clinical management of the most common arthropathy, osteoarthritis (OA). A task force (including rheumatologists, radiologists, methodologists, primary care doctors and patients) from nine countries defined 10 questions on the role of imaging in OA to support a systematic literature review (SLR). Joints of interest were the knee, hip, hand and foot; imaging modalities included conventional radiography (CR), MRI, ultrasonography, CT and nuclear medicine. PubMed and EMBASE were searched. The evidence was presented to the task force who subsequently developed the recommendations. The strength of agreement for each recommendation was assessed. 17 011 references were identified from which 390 studies were included in the SLR. Seven recommendations were produced, covering the lack of need for diagnostic imaging in patients with typical symptoms; the role of imaging in differential diagnosis; the lack of benefit in monitoring when no therapeutic modification is related, though consideration is required when unexpected clinical deterioration occurs; CR as the first-choice imaging modality; consideration of how to correctly acquire images and the role of imaging in guiding local injections. Recommendations for future research were also developed based on gaps in evidence, such as the use of imaging in identifying therapeutic targets, and demonstrating the added value of imaging. These evidence-based recommendations and related research agenda provide the basis for sensible use of imaging in routine clinical assessment of people with OA.

Review of Prospects of Biological Fluid Biomarkers in Osteoarthritis

Osteoarthritis (OA) is a degenerative disease of the joints and is one of the leading causes of disability in adults. However, there are no key therapeutics for OA and medical treatment is based on managing the symptoms and slowing down progression of the disease. Diagnostics based on clinical examination and radiography have provided little information about metabolic changes in joint tissues, disease onset and progression. Due to lack of effective methods for early detection and evaluation of treatment outcome, the measurement of biochemical markers (biomarkers) shows promise as a prospective method aiding in disease monitoring. OA biomarkers that are present in biological fluids such as blood, urine and synovial fluid, sources that are easily isolated from body, are of particular interest. Moreover, there are increasingly more studies identifying and developing new biomarkers for OA. In this review, efforts have been made to summarize the biomarkers that have been reported in recent studies on patients. We also tried to classify biomarkers according to tissue metabolism (bone, cartilage and synovial metabolism markers), pathological pathways (inflammatory and genetic markers) and biological function (chemokines, growth factors, acute phase proteins, etc.).

Intra-Articular Injection of Cross-Linked Hyaluronic Acid-Dexamethasone Hydrogel Attenuates Osteoarthritis: An Experimental Study in a Rat Model of Osteoarthritis

Cross-linked hyaluronic acid hydrogel (cHA gel) and dexamethasone (Dex) have been used to treat knee osteoarthritis (OA) in clinical practice owing to their chondroprotective and anti-inflammatory effects, respectively. The aim of the present study was to compare the treatment effects of the cHA gel pre-mixed with/without Dex in a surgery-induced osteoarthritis model in rats. Anterior cruciate ligament transection (ACLT) surgery was performed on the right knee of rats to induce OA. Male 2-month-old Sprague-Dawley rats were randomly divided into five groups (n = 10/per group): (1) ACLT + saline; (2) ACLT + cHA gel; (3) ACLT + cHA-Dex (0.2 mg/mL) gel; (4) ACLT + cHA-Dex (0.5 mg/mL) gel; (5) Sham + saline. Intra-joint injections were performed four weeks after ACLT in the right knee. All animals were euthanized at 12 weeks post-surgery. Cartilage damage and changes in the synovial membrane were assessed by micro X-ray, Indian ink articular surface staining, Safranin-O/Fast Green staining, immunohistochemistry, hematoxylin and eosin staining of the synovial membrane, and quantitative reverse transcription-polymerase chain reaction for changes in gene expression. Micro X-ray revealed that the knee joint treated with the cHA-Dex gel was wider than those treated with cHA gel alone or saline. The cHA-Dex gel group had less Indian ink staining (indicator of cartilage fibrillation) than the cHA gel or saline injection groups. Safranin-O/Fast Green staining indicated that increased proteoglycan staining and less cartilage damage were found in the cHA-Dex gel group compared with the cHA gel or saline injection groups. Quantification of histology findings from saline, cHA gel, cHA-Dex (0.2 mg/mL) gel, cHA-Dex (0.5 mg/mL) gel, and sham groups were 5.84 ± 0.29, 4.50 ± 0.87, 3.00 ± 1.00, 2.00 ± 0.48, and 0.30 ± 0.58 (p < 0.05), respectively. A strong staining of type II collagen was found in both the cHA-Dex gel groups compared with saline group or cHA alone group. Similar result was found for the mRNA level of aggrecan and opposite result for type X collagen. Hematoxylin and eosin staining in the synovial membrane showed less synovial lining cell layers and reduced inflammatory cell infiltration in cHA-Dex gel-treated animals compared with saline or cHA only groups. Altogether, cHA-Dex gel has better chondroprotective and anti-inflammatory effects in rat surgery-induced osteoarthritis than cHA alone.

Serum hyaluronic acid concentration predicts the progression of joint space narrowing in normal knees and established knee osteoarthritis - a five-year prospective cohort study

Introduction

Serum hyaluronic acid (sHA) is a serum biomarker for knee osteoarthritis (OA). Although sHA concentration is elevated in patients with knee OA, the relationship between serum concentration and disease progression remains unclear. We examined the relationship between sHA concentration and radiographic progression of knee OA in a cohort of individuals followed for 5 years.

Methods

We prospectively enrolled 444 individuals and measured their sHA concentrations at baseline. Anterior-posterior weight bearing knee radiographs were obtained at baseline and the 5-year endpoint. Osteoarthritic knee changes were classified according to Kellgren–Lawrence (KL) grade, and joint space narrowing (JSN) was measured using a Knee Osteoarthritis Computer-Aided Diagnosis (KOACAD) system. Correlations between sHA concentration, progression in KL grade, and JSN were assessed using regression models, taking into account potentially confounding factors.

Results

OA progressed from KL grades 0 or 1 in 129 of the 323 knees, and from KL grades 2 or 3 in 61 of the 119 knees. Higher sHA concentrations were correlated with KL grade progression (p = 0.004). The mean JSN, as assessed by KOACAD over 5 years, was 0.23 ± 0.55 mm, and sHA concentration was positively correlated with progression of JSN in KL grades 0 or 1 (p = 0.021) and KL grades 2 or 3 (p = 0.008) knees.

Conclusion

Serum HA concentration was positively correlated with progression of KL grade. sHA was also positively correlated with progression of JSN in knees with and without OA, suggesting that sHA concentration may be a useful predictor of knee OA progression.

What Are the Prognostic Factors for Radiographic Progression of Knee Osteoarthritis? A Meta-analysis

BACKGROUND

A previous systematic review on prognostic factors for knee osteoarthritis (OA) progression showed associations for generalized OA and hyaluronic acid levels. Knee pain, radiographic severity, sex, quadriceps strength, knee injury, and regular sport activities were not associated. It has been a decade since the literature search of that review and many studies have been performed since then investigating prognostic factors for radiographic knee OA progression.

QUESTIONS/PURPOSES

The purpose of this study is to provide an updated systematic review of available evidence regarding prognostic factors for radiographic knee OA progression.

METHODS

We searched for observational studies in MEDLINE and EMBASE. Key words were: knee, osteoarthritis (or arthritis, or arthrosis, or degenerative joint disease), progression (or prognosis, or precipitate, or predictive), and case-control (or cohort, or longitudinal, or follow-up). Studies fulfilling the inclusion criteria were assessed for methodologic quality according to established criteria for reviews on prognostic factors in musculoskeletal disorders. Data were extracted and results were pooled if possible or summarized according to a best-evidence synthesis. A total of 1912 additional articles were identified; 43 met our inclusion criteria. The previous review contained 36 articles, thus providing a new total of 79 articles. Seventy-two of the included articles were scored high quality, the remaining seven were low quality.

RESULTS

The pooled odds ratio (OR) of two determinants showed associations with knee OA progression: baseline knee pain (OR, 2.38 [95% CI, 1.74-3.27) and Heberden nodes (OR, 2.66 [95% CI, 1.46-8.84]). Our best-evidence synthesis showed strong evidence that varus alignment, serum hyaluronic acid, and tumor necrosis factor-α are associated with knee OA progression. There is strong evidence that sex, former knee injury, quadriceps strength, smoking, running, and regular performance of sports are not associated with knee OA progression. Evidence for the majority of determined associations, however, was limited, conflicting, or inconclusive.

CONCLUSIONS

Baseline knee pain, presence of Heberden nodes, varus alignment, and high levels of serum markers hyaluronic acid and tumor necrosis factor-α predict knee OA progression. Sex, knee injury, and quadriceps strength, among others, did not predict knee OA progression. Large variation remains in definitions of knee OA and knee OA progression. Clinical studies should use more consistent definitions of these factors to facilitate data pooling by future meta-analyses.

Hyaluronan molecular weight distribution is associated with the risk of knee osteoarthritis progression

OBJECTIVE

We investigated the relationship between the molecular weight (MW) distribution of hyaluronan (HA) in synovial fluid (SF) and risk of knee osteoarthritis (OA) progression.

METHODS

HA MW was analyzed for 65 baseline knee SFs. At 3-year follow-up, knees were scored for change in joint space narrowing (JSN), osteophyte (OST) progression, or occurrence of total knee arthroplasty (TKA). HA MW distribution was analyzed using agarose gel electrophoresis (AGE), and its relationship to OA progression was evaluated using logistic regression. The association between HA MW and self-reported baseline knee pain was analyzed using Pearson's correlation coefficients.

RESULTS

Knee OA was categorized as non-progressing (OST-/JSN-, 26 knees, 40%), or progressing based on OST (OST+/JSN-, 24 knees, 37%), OST and JSN (OST+/JSN+, 7 knees, 11%) or total knee arthroplasty (TKA, 8 knees, 12%). The MW distribution of HA in baseline SFs was significantly associated with the odds of OA progression, particularly for index knees. After adjusting for age, gender, BMI, baseline X-ray grade and pain, each increase of one percentage point in %HA below 1 million significantly increased the odds of JSN (odds ratios (OR) = 1.45, 95% CI 1.02-2.07), TKA or JSN (OR = 1.24, 95%CI 1.01-1.53) and the odds of any progression (OR = 1.16, 95% CI 1.01-1.32). HA MW distribution significantly correlated with pain.

CONCLUSION

These data suggest that the odds of knee OA progression increases as HA MW distribution shifts lower and highlight the value of reporting MW distribution rather than just average MW values for HA.

Role of hyaluronic Acid in early diagnosis of knee osteoarthritis

INTRODUCTION

Osteoarthritis of knee is traditionally diagnosed on the basis of clinical and radiological findings. Usually joint tissue degeneration is already advanced by the time a clinical diagnosis is made, hence the research focus has now shifted to use of biomarkers to diagnose the condition at an early stage of the disease.

AIMS & OBJECTIVES

The aim of this study was to assess the efficacy of serum HA levels in early detection and grading of the severity of primary knee osteoarthritis and it's co-relation with Western Ontario and McMaster university osteoarthritis index (WOMAC scores) and Kellgren -Lawrence grading (K-L grade).

MATERIALS AND METHODS

The study included 150 subjects (100 cases and 50 controls) and all were subjected to WOMAC scoring and K-L grading and estimation of serum HA levels.

RESULTS

Age and WOMAC scores have significant correlation with HA levels, but multivariate analysis shows only WOMAC score as an independent variable associated with HA levels. The results show statistically significant high HA levels in cases than in normal population. HA levels are also able to differentiate between various clinical severity grades. ROC Curve analysis suggests cut-off levels of HA between mild, moderate and severe cases.

CONCLUSION

HA levels are able to differentiate between normal asymptomatic population and symptomatic cases and also between various severity grades of osteoarthritis.

Study of treadmill exercise effect on rats with osteoarthritis using proteomic analysis

[Purpose] To investigate the correlation between the effect treadmill exercise and change in serum proteins in rats with osteoarthritis, a study of proteins was carried out using a mass spectrometer. [Subjects and Methods] Rats were randomly divided into five groups. After 4 weeks of treadmill training, serum from each rat was analyzed by Liquid chromatography-electrospray ionization tandem mass spectrometry. Complementary component 9 (C9) was discovered to be downregulated in the serum of the exercise groups, and this was validated by Western blot. [Results] Seventeen proteins were discovered to be elevated in the monosodium iodoacetate injection osteoarthritis group samples by more than 1.5 fold compared with the control group. One of the proteins upregulated, C9 protein, was validated, and it was found to decrease in the middle-intensity exercise group. [Conclusion] We showed that the serum level of C9, an inflammatory-related protein, decreased after treadmill exercise. Therefore, treadmill exercise with an appropriate intensity might be recommended for OA patients.

Association of Cross Linked C-Telopeptide II Collagen and Hyaluronic Acid with Knee Osteoarthritis Severity

BACKGROUND: This study was carried out to investigate the association of Cross Linked C-Telopeptide Type I & II Collagen (CTX-I and II) and hyaluronic acid (HA) with knee osteoarthritis (OA) severity.METHODS: Sixty menopause women with primary knee OA were enrolled in this study during their visits to the Outpatient Department. Patients with knee pain during weight bearing, active or passive range of motion, or tenderness with Kellgren-Lawrence (KL) grade of more than I were included. Patients with injury, inflammatory and metabolic diseases were excluded. Patients were put in a 10-hour fasting prior to withdrawal of morning blood samples for examinations of HA, CTX-I, interleukin 1 beta (IL-1β), and high sensitivity C reactive protein (hs-CRP) level. Second void morning urine specimens were taken for CTXII assessment. HA, CTX-I and II levels were measured by enzyme-linked immunosorbent assay.RESULTS: Sixty menopausal female patients were included in this study, 35 with KL grade II, 17 grade III, and 8 grade IV. Means of CTX-II were significantly different between subjects KL grade IV and III (p=0.021). Correlation of KL grade was significant with CTX-II (p=0.001, r=0.412) and HA (p=0.0411, r=0.269). KL grades were not significantly associated with CTX-I (p=0.8364, r=-0.0272); IL-1β (p=0.5773, r=0.0853) and hs-CRP (p=0.2625, r=0.1470).CONCLUSION: CTX-II and HA were associated with severity of knee OA, suggesting that CTX-II and HA can be used as marker for knee OA severity.KEYWORDS: CTX-II, hyaluronic acid, otestoarthritis, knee

Interplay between cartilage and subchondral bone contributing to pathogenesis of osteoarthritis

Osteoarthritis (OA) is a common debilitating joint disorder, affecting large sections of the population with significant disability and impaired quality of life. During OA, functional units of joints comprising cartilage and subchondral bone undergo uncontrolled catabolic and anabolic remodeling processes to adapt to local biochemical and biological signals. Changes in cartilage and subchondral bone are not merely secondary manifestations of OA but are active components of the disease, contributing to its severity. Increased vascularization and formation of microcracks in joints during OA have suggested the facilitation of molecules from cartilage to bone and vice versa. Observations from recent studies support the view that both cartilage and subchondral bone can communicate with each other through regulation of signaling pathways for joint homeostasis under pathological conditions. In this review we have tried to summarize the current knowledge on the major signaling pathways that could control the cartilage-bone biochemical unit in joints and participate in intercellular communication between cartilage and subchondral bone during the process of OA. An understanding of molecular communication that regulates the functional behavior of chondrocytes and osteoblasts in both physiological and pathological conditions may lead to development of more effective strategies for treating OA patients.

Identification of potential prognostic markers for knee osteoarthritis by serum proteomic analysis

BACKGROUND

As osteoarthritis (OA) is a highly heterogeneous disease in terms of progression, establishment of prognostic biomarkers would be highly beneficial for treatment. The present study was performed to identify novel biomarkers capable of predicting the progression of knee OA.

METHODS

A total of 69 plasma samples (OA patients undergoing radiographic progression, n = 25; nonprogression, n = 33; healthy donors, n = 11) were analyzed by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS), and ion peaks of interest were identified by liquid chromatography and matrix-assisted laser desorption/ionization (MALDI)-TOF MS. The identities of these proteins were further validated by immunoprecipitation combined with SELDI-TOF MS analysis.

RESULTS

SELDI-TOF MS analysis indicated that the intensities of 3 ion peaks differed significantly between progressors and nonprogressors. Subsequent analyses indicated that these peaks corresponded to apolipoprotein C-I, C-III, and an N-terminal truncated form of transthyretin, respectively. The identities of these proteins were confirmed by the loss of ion peaks in SELDI-TOF MS spectra by immunoprecipitation using specific antibodies for the respective proteins.

CONCLUSIONS

Three potential biomarkers were identified whose serum levels differed significantly between OA progressors and nonprogressors. These biomarkers are expected to be prognostic biomarkers for knee OA and to facilitate the development of novel disease-modifying treatments for OA.

Serum hyaluronan levels increase with the total number of osteoarthritic joints and are strongly associated with the presence of knee and finger osteoarthritis

PURPOSE

Although serum hyaluronan (HA) levels increase in patients with osteoarthritis (OA), the association between OA severity and elevation of serum HA levels is not clear. Our purpose was to investigate the relationship between serum HA levels and OA in various anatomical sites and to detect which joints are strongly correlated with elevated serum HA levels.

METHODS

Seven hundred and ten individuals from the general population who participated in the Iwaki Health Promotion Project in 2008 were involved. Kellgren-Lawrence grade 2 or higher in the knee, hip, lumbar spine, finger and wrist was defined as OA. Serum HA levels were determined on the same day. Spearman's correlation coefficients between serum HA levels and total number of joints affected by OA were calculated. Linear regression was analysed with serum HA levels as the independent variable; age, gender, presence of OA and intake of supplements were used as dependent variables.

RESULTS

Prevalence of knee OA was 30.7 %, hip 16.8 %, lumbar spine 65.1 %, wrist 9.0 % and finger 22.0 %. Serum HA levels had a positive correlation with the number of involved joints, and the correlation coefficient was 0.410 (p < 0.001). Serum HA was significantly affected by age (β = 0.382), knee OA (β = 0.163) and finger OA (β = 0.164).

CONCLUSION

Although this biomarker reflects a systemic condition, higher serum HA levels were associated with total number of OA joints. Knee and finger OA were key joints related to increased serum HA levels. These results are valuable in understanding characteristics of serum HA levels as a biomarker for osteoarthritis.

Serological markers of erosive hand osteoarthritis

This review focuses on biomarkers in erosive hand osteoarthritis (EHOA), a subset of hand osteoarthritis (HOA), that primarily affects interphalangeal joints and is characterized by abrupt onset, severe pain and functional impairment, as well as signs of inflammation, in particular stiffness, swelling, erythema, paraesthesiae, and worse outcome. Inflammatory features and radiographic erosions are the main diagnostic hallmarks of this particular disease subset. As in other fields of OA, EHOA biomarkers can be classified as dry and soluble. Soluble biomarkers which are found in serum, synovial fluid and urine can be specific indicators of joint inflammation and degradation. With regard to inflammatory markers, C-reactive protein and myeloperoxidase have been found to be increased in EHOA, with respect to non-erosive HOA. All these markers have, moreover, been found to be correlated with disease activity. Another interesting marker linked to inflammation is hyaluronic acid, considered to be a marker of synovitis, which is frequently found in EHOA. The most useful cartilage markers in both erosive and non-erosive HOA, seems to be collagen (Coll) 2-1, Coll 2-1NO(2) and Col2-3/4C(short). Immunogenetic markers were also determined and an association between EHOA and a single nucleotide polymorphism on the gene encoding interleukin-1β was found in HLA and there was an increased frequency of HLA-B44 and HLA-DRB1*07 in EHOA.

Association between serum and urine biomarkers and lumbar spine individual radiographic features: the Johnston County Osteoarthritis Project

OBJECTIVE

(1) To determine associations between radiographic features of lumbosacral (LS) spine disc space narrowing (DSN) and osteophytes (OST) and joint metabolism biomarkers (serum cartilage oligomeric matrix protein (COMP), hyaluronic acid (HA), collagen neoepitope (C2C), C-propeptide of type II procollagen (CP-II), urine C-terminal cross-linking telopeptide (CTX-II) and N-terminal telopeptide (NTX-I)). (2) To explore interactions with race, gender and low back symptoms.

DESIGN

Cross-sectional analysis of 547 participants enrolled in the Johnston County (JoCo) Osteoarthritis Project from 2003 to 2004. Mean biomarker levels were estimated with linear regression. Proportional and partial-proportional odds models were used to estimate associations. Interactions were tested with likelihood ratio tests at a P-value < 0.10. Biomarkers were natural log (ln) transformed.

RESULTS

Significant differences in mean biomarker levels were found across severity of DSN for lnHA and lnC2C and lnCTX-II across severity of both DSN and OST. Moderate-to-strong associations were found between biomarkers of type II collagen and DSN, whereas associations with OST were weak. An association between lnHA and DSN was seen in women (adjusted odds ratio [aOR] = 1.34 (95% confidence intervals (CI) 1.08, 1.65)) but no association among men (aOR = 0.90 (95% CI 0.63, 1.26)). In Caucasians there was a decreased association with NTX-I and OST (aOR = 0.67 (95% CI 0.49, 0.91)) and no association in African Americans (AAs) (aOR = 1.06 (95% CI 0.76, 1.47)). There was a positive association of lnCOMP with DSN among those with low back symptoms (aOR = 1.82 (95% CI 1.02, 3.27)), but no association in those without low back symptoms (aOR = 0.65 (95% CI 0.35, 1.20)).

CONCLUSION

Joint metabolism biomarkers suggest biological differences in the pathologic process involved in DSN and OST that may be gender (HA) and ethnicity (NTX-I) specific.

Biological markers in osteoarthritis

Osteoarthritis (OA) is considered as a chronic disease with a long "silent" period. The diagnosis is generally based on clinical symptoms and radiographic changes. However X-ray has a poor sensitivity and a relatively large precision error that does not allow an early detection of OA or the monitoring of joint damage progression. The limitations of the tools that are currently available for OA assessment have been the impetus to identify specific biological markers that reflect quantitative and dynamic variations in joint remodeling. Research has focused on the structural components of cartilage matrix, especially type II collagen degradation markers. In spite of a significant increase of some markers in individuals with early stage of OA, the large overlap with control subjects indicates that the current biomarkers used alone have limited diagnostic potential. However, the combination of specific markers seems to improve the prediction of disease progression at the individual level. Several types of treatment have been investigated but the lack of medications with definitively demonstrated chondroprotective activity has limited the assessment of the potential role of biomarkers for monitoring patients' responses to the treatment of OA. In this review, we will use the BIPED classification that appeared in 2006 for OA markers to describe the potential usage of a given marker [5]. This article is part of a Special Issue entitled "Osteoarthritis".

Potential plasma biomarkers for progression of knee osteoarthritis using glycoproteomic analysis coupled with a 2D-LC-MALDI system

Background

Although osteoarthritis (OA) is a highly prevalent joint disease, to date, no reliable biomarkers have been found for the disease. In this study, we attempted to identify factors the amounts of which significantly change in association with the progression of knee OA.

Methods

A total of 68 subjects with primary knee OA were enrolled in the study. These subjects were followed up over an 18-month period, and plasma and serum samples were obtained together with knee radiographs every 6 months, i.e., 0, 6, 12 and 18 months after the enrollment. Progressors and non-progressors were determined from the changes on radiographs, and plasma samples from those subjects were subjected to N-glycoproteomic 2D-LC-MALDI analysis. MS peaks were identified, and intensities for respective peaks were compared between the progressors and non-progressors to find the peak intensities of which differed significantly between the two groups of subjects. Proteins represented by the chosen peaks were identified by MS/MS analysis. Expression of the identified proteins was evaluated in synovial tissues from 10 OA knee joints by in situ hybridization, western blotting analysis and ELISA.

Results

Among the subjects involved in the study, 3 subjects were determined to be progressors, and 6 plasma and serum samples from these subjects were subjected to the analysis together with another 6 samples from the non-progressors. More than 3000 MS peaks were identified by N-glycoproteomic 2D-LC-MALDI analysis. Among them, 4 peaks were found to have significantly different peak intensities between the progressors and non-progressors. MS/MS analysis revealed that these peaks represented clusterin, hemopexin, alpha-1 acid glycoprotein-2, and macrophage stimulating protein, respectively. The expression of these genes in OA synovium was confirmed by in situ hybridization, and for clusterin and hemopexin, by western blotting analysis and ELISA as well.

Conclusions

In this study, 4 potential biomarkers were identified as potential prognostic markers for knee OA through N-glycoproteomic analysis. To the best of our knowledge, this is the first report for the use of glycoproteomic technology in exploring potential biomarkers for knee OA.

Pentosidine, an advanced glycation end-product, may reflect clinical and morphological features of hand osteoarthritis

The study investigates pentosidine levels, an advanced glycation end-product, in patients with erosive and non-erosive hand osteoarthritis (HOA) and determine its potential association with clinical findings and imaging-defined joint damage.Pentosidine was measured by HPLC in serum and urine of 53 females with HOA (31 erosive and 22 non-erosive HOA) and normalised to the total serum protein or urinary creatinine, respectively. Pain, joint stiffness and disability were assessed by the Australian/Canadian OA hand index (AUSCAN). The hand radiographs scored according to the Kallman grading scale were assessed to determine a baseline value and reassessed after two years.The levels of urine pentosidine, but not of serum pentosidine, were higher in patients with erosive HOA than in non-erosive HOA (p=0.039). Urinary pentosidine correlated with CRP (r=0.302, p=0.031), ESR (r=0.288, p=0.041) and AUSCAN (r=0.408, p=0.003). Serum pentosidine, but not in urine, significantly correlated with the Kallman radiographic score in erosive HOA at the baseline (r=0.409, p=0.022) and after 2 years (r=0.385, p=0.032). However, when corrected for age and disease duration, only correlation between urine pentosidine and AUSCAN remained significant (r=0.397, p=0.004).Our data suggest that serum and urine pentosidine levels may relate to the distinctive clinical and morphological features of HOA.

In end stage osteoarthritis, cartilage tissue pentosidine levels are inversely related to parameters of cartilage damage

OBJECTIVES

Age is the most prominent predisposition for development of osteoarthritis (OA). Age-related changes of articular cartilage are likely to play a role. Advanced glycation endproducts (AGEs) accumulate in cartilage matrix with increasing age and adversely affect the biomechanical properties of the cartilage matrix and influence chondrocyte activity. In clinical studies AGEing of cartilage and its relation to actual cartilage damage can only be measured by surrogate markers (e.g., serum, skin or urine AGE levels and imaging or biochemical markers of cartilage damage). In this study actual cartilage AGE levels were directly related to actual cartilage damage by use of cartilage obtained at joint replacement surgery.

METHODS

Cartilage and urine samples were obtained from 69 patients undergoing total knee replacement. Samples were analyzed for pentosidine as marker of AGE. Cartilage damage was evaluated macroscopically, histologically, and biochemically.

RESULTS

Cartilage and urine pentosidine both increased with increasing age. The higher the macroscopic, histological, and biochemical cartilage damage the lower the cartilage pentosidine levels were. In multiple regression analysis age is not found to be a confounder.

CONCLUSION

There is an inverse relation between cartilage AGEs and actual cartilage damage in end-stage OA. This is likely due to ongoing (ineffective) increased turnover of cartilage matrix proteins even in end stage disease.

Measurement of MMP Activity in Synovial Fluid in Cases of Osteoarthritis and Acute Inflammatory Conditions of the Knee Joints Using a Fluorogenic Peptide Probe-Immobilized Diagnostic Kit

PURPOSE

A fluorogenic peptide probe-immobilized diagnostic kit was used to analyze MMP activity in the synovial fluids (SFs) from patients with osteoarthritis (OA) and acute inflammatory conditions of the knee joint.

METHODS

The MMP diagnostic kit containing a polymer-conjugated MMP probe immobilized on a 96-well plate was utilized for high-throughput screening of MMP activity in SFs from OA patients (n = 33) and patients with acute inflammatory conditions of the knee joint (n = 5).

RESULTS

Compared to SF from OA patients, SF from patients with acute inflammatory conditions of the knee joint presented stronger NIR fluorescent signals. In gelatin zymography, most samples from patients with acute inflammatory conditions of the knee joint also displayed 92 kDa (pro-form) MMP-9 and faint 84 kDa (active form) MMP-9, while SF from OA patients did not display detectable MMP-9 activity .

CONCLUSION

The presence of a strong fluorescence signal from the MMP diagnostic kit corresponded well with patients with acute inflammatory conditions of the knee joint. The results suggest that our MMP diagnostic kit can be useful in differentiation between early stages of OA and acute inflammatory conditions of the knee joint.

Serum cartilage oligomeric matrix protein (sCOMP) is elevated in patients with knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

To be used in diagnostic studies, it must be demonstrated that biomarkers can differentiate between diseased and non-diseased patients. Therefore, the purpose of this study was to answer the following questions: (1) Is serum cartilage oligomeric matrix protein (sCOMP) elevated in patients with radiographically diagnosed knee osteoarthritis (OA) compared to controls? (2) Are there differences in sCOMP levels when comparing differing radiographic OA severities to controls?

METHODS

Systematic review and meta-analysis.

DATA SOURCES

A systematic search of CINAHL, PEDro, Medline, and SportsDiscus was completed in March 2010.

KEYWORDS

knee, osteoarthritis, sCOMP, radiography. Study inclusion criteria: Studies were written in English, compared healthy adults with knee OA patients, used the Kellgren Lawrence (K/L) classification, measured sCOMP, and reported means and standard deviations for sCOMP.

RESULTS

For question 1, seven studies were included resulting in seven comparisons. A moderate overall effect size (ES) indicated sCOMP was consistently elevated in those with radiographically diagnosed knee OA when compared to controls (ES = 0.60, P < 0.001). For question 2, four studies were included resulting in 13 comparisons between radiographic OA severity levels and controls. Strong ESs were calculated for K/L-1 (ES = 1.43, P = 0.28), K/L-3 (ES = 1.05, P = 0.04), and K/L-4 (ES = 1.40, P = 0.003). A moderate ES was calculated for K/L-2 (ES = 0.60, P = 0.01).

CONCLUSIONS

These results indicate sCOMP is elevated in patients with knee OA and is sensitive to OA disease progression. Future research studies with a higher level of evidence should be conducted to investigate the use of this biomarker as an indicator for OA development and progression.

Association of plasma and synovial fluid interferon-γ inducible protein-10 with radiographic severity in knee osteoarthritis

OBJECTIVES

The objective of this study was to investigate interferon-γ inducible protein-10 (IP-10) concentrations in plasma and synovial fluid of patients with knee osteoarthritis (OA) and to analyze their relationship with disease severity.

DESIGN AND METHODS

Forty OA patients and 15 healthy controls were enrolled in this study. OA grading was performed according to the Kellgren-Lawrence criteria. IP-10 levels in plasma and synovial fluid were assessed using enzyme-linked immunosorbent assay.

RESULTS

Plasma IP-10 levels in the knee OA patients were significantly lower than those of controls (P=0.006). IP-10 levels in plasma were markedly higher with regard to paired synovial fluid (P<0.001). Furthermore, IP-10 concentrations in plasma and synovial fluid displayed significant inverse correlation with radiographic severity (r=-0.713, P<0.001 and r=-0.561, P<0.001, respectively). Subsequent analysis revealed that plasma IP-10 levels were positively correlated with synovial fluid IP-10 levels (r=0.424, P=0.006).

CONCLUSIONS

IP-10 levels in both plasma and synovial fluid were inversely associated with the severity of knee OA. Accordingly, IP-10 could serve as a biomarker for determining disease severity and might play a possible role in the pathophysiology of osteoarthritis.

Acute joint pathology and synovial inflammation is associated with increased intra-articular fracture severity in the mouse knee

OBJECTIVE

Post-traumatic arthritis is a frequent cause of disability and occurs most commonly and predictably after articular fracture. The objective of this investigation was to examine the effect of fracture severity on acute joint pathology in a novel murine model of intra-articular fracture.

DESIGN

Low and high energy articular fractures (n=25 per group) of the tibial plateau were created in adult male C57BL/6 mice. The acute effect of articular fracture severity on synovial inflammation, bone morphology, liberated fracture area, cartilage pathology, chondrocyte viability, and systemic cytokines and biomarkers levels was assessed at 0, 1, 3, 5, and 7 days post-fracture.

RESULTS

Increasing intra-articular fracture severity was associated with greater acute pathology in the synovium and bone compared to control limbs, including increased global synovitis and reduced periarticular bone density and thickness. Applied fracture energy was significantly correlated with degree of liberated cortical bone surface area, indicating greater comminution. Serum concentrations of hyaluronic acid (HA) were significantly increased 1 day post-fracture. While articular fracture significantly reduced chondrocyte viability, there was no relationship between fracture severity and chondrocyte viability, cartilage degeneration, or systemic levels of cytokines and biomarkers.

CONCLUSIONS

This study demonstrates that articular fracture is associated with a loss of chondrocyte viability and increased levels of systemic biomarkers, and that increased intra-articular fracture severity is associated with increased acute joint pathology in a variety of joint tissues, including synovial inflammation, cortical comminution, and bone morphology. Further characterization of the early events following articular fracture could aid in the treatment of post-traumatic arthritis.

Effect of a glucosamine-based combination supplement containing chondroitin sulfate and antioxidant micronutrients in subjects with symptomatic knee osteoarthritis: A pilot study

In the present study, we aimed to investigate the potential effect of a glucosamine (1,200 mg/day)-based dietary supplement combined with chondroitin sulfate and three antioxidant micronutrients, namely methylsulfonylmethane, guava leaf extract, and vitamin D (test supplement) on osteoarthritis (OA) of the knee. A 16-week, randomized, double-blinded, placebo-controlled trial was conducted involving 32 subjects with symptomatic knee OA. Clinical outcomes were measured using the Japanese Knee Osteoarthritis Measure (JKOM) for symptoms and a study diary-based visual analog scale (diary VAS) for pain at baseline and at weeks 4, 8, 12 and 16 during the 16-week intervention period. Furthermore, biomarkers for cartilage type II collagen degradation (C2C) and synovitis hyaluronan (HA) were measured. As compared with the baseline, the JKOM pain subscale was significantly improved at all of the four assessment time points in the test group, but was not at any time point in the placebo group. On the other hand, all of the four symptom subscales and the aggregated total symptoms were significantly improved in the two groups at one or more time points. However, all of these clinical improvements were greater in extent in the test group than in the placebo group, and there were significant differences between groups in the magnitude of changes from baseline for one subscale 'general activities' and the aggregated total symptoms at week 8 (P<0.05). The results of efficacy assessments with the diary VAS showed that all of the three pain subscales were significantly improved only in the test group at almost all the time points. Moreover, serum levels of C2C and HA were decreased by 10 and 25%, respectively, at week 16 in the test group, albeit not statistically significant, without any detectable changes in the placebo group. In conclusion, although the results obtained in this study were not conclusive, the tested glucosamine-based combination supplement is likely to have a beneficial effect on pain and other symptoms associated with knee OA.

Responsiveness to change and reliability of measurement of radiographic joint space width in osteoarthritis of the knee: a systematic review

OBJECTIVE

The goal of this systematic review was to report the responsiveness to change and reliability of conventional radiographic joint space width (JSW) measurement.

METHOD

We searched the PubMed and Embase databases using the following search criteria: [osteoarthritis (OA) (MeSH)] AND (knee) AND (X-ray OR radiography OR diagnostic imaging OR radiology OR disease progression) AND (joint space OR JSW or disease progression). We assessed responsiveness by calculating the standardized response mean (SRM). We assessed reliability using intra- and inter-reader intra-class correlation (ICC) and coefficient of variation (CV). Random-effects models were used to pool results from multiple studies. Results were stratified by study duration, design, techniques of obtaining radiographs, and measurement method.

RESULTS

We identified 998 articles using the search terms. Of these, 32 articles (43 estimates) reported data on responsiveness of JSW measurement and 24 (50 estimates) articles reported data on measures of reliability. The overall pooled SRM was 0.33 [95% confidence interval (CI): 0.26, 0.41]. Responsiveness of change in JSW measurement was improved substantially in studies of greater than 2 years duration (0.57). Further stratifying this result in studies of greater than 2 years duration, radiographs obtained with the knee in a flexed position yielded an SRM of 0.71. Pooled intra-reader ICC was estimated at 0.97 (95% CI: 0.92, 1.00) and the intra-reader CV estimated at 3.0 (95% CI: 2.0, 4.0). Pooled inter-reader ICC was estimated at 0.93 (95% CI: 0.86, 0.99) and the inter-reader CV estimated at 3.4% (95% CI: 1.3%, 5.5%).

CONCLUSIONS

Measurement of JSW obtained from radiographs in persons with knee is reliable. These data will be useful to clinicians who are planning RCTs where the change in minimum JSW is the outcome of interest.

Knee osteoarthritis, knee joint pain and aging in relation to increasing serum hyaluronan level in the Japanese population

OBJECTIVE

To investigate relationship between serum hyaluronan (HA) level and the presence and severity of radiographic knee osteoarthritis (OA) as well as degree of knee pain in Japanese population.

DESIGN

A total of 616 volunteers participated in this study. Based on the Kellgren-Lawrence (K-L) grade, participants were radiographically classified into three groups: Normal (K-L grade 0 or 1), Moderate (grade 2) and Severe (grade 3 or 4). The degree of knee pain was quantified by visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) Pain. Serum HA levels were compared among the Normal, Moderate and Severe groups, and the relationship between serum HA level and the severity of knee OA was analyzed after age, sex and body mass index (BMI) were adjusted. In addition, the correlation between serum HA level and the degree of knee pain was analyzed in each group.

RESULTS

Regarding relationship between serum HA level and the severity of radiographic knee OA, serum HA levels of the Moderate and Severe groups were significantly higher than in the Normal group (P<0.001). Furthermore, serum HA level correlated with the severity of radiographic knee OA (r=0.289, P<0.001) after adjusting for age, sex and BMI. Serum HA level correlated with VAS of knee pain and/or KOOS Pain in the Normal and Moderate groups.

CONCLUSION

Serum HA level has the potential to be useful for the diagnosis of the presence and severity of knee OA.

Efficacy of intra-articular injection of celecoxib in a rabbit model of osteoarthritis

Introduction: Osteoarthritis is the most common form of arthritis. It is a slowly progressive joint disease typically seen in middle-age to elderly people. Intra-articular injection of hyaluronic acid is a well-documented treatment for knee osteoarthritis. Celebrex^® (celecoxib) is a novel nonsteroidal anti-inflammatory drug, which could help to reduce inflammation and to reduce pain. The aim of this study was to evaluate the effects of intra-articular injection of celecoxib in a rabbit osteoarthritis model. Methods: Thirty New Zealand white rabbits underwent unilateral knee joint surgery using the Hulth technique. Six weeks post-surgery, the animals were randomly divided into three groups, and each group was respectively given weekly intra-articular injections with Celebrex^®, hyaluronic acid and saline. On the sixth week, the results were assessed in rabbit models by gross observation, histological evaluation, and expression of IL-1β, TNF-α, MMP-3. Results: In the group given Celebrex^® and hyaluronic acid, the pathological changes in the rabbit articular cartilage improved significantly, much more than in the saline group. The statistically significant suppression of IL-1β, TNF-α, MMP-3 was shown in the Celebrex group. No significant differences were detected between two treatment groups. Conclusions: Intra-articular injection of celecoxib is beneficial for knee osteoarthritis. It might repair and protect early osteoarthritis cartilage by delaying cartilage degeneration and impairing the function of inflammatory mediators, therefore, intra-articular injection of celecoxib can be used as an alternative to the current treatment of osteoarthritis.

Skin and urine pentosidine weakly correlate with joint damage in a cohort of patients with early signs of osteoarthritis (CHECK)

OBJECTIVES

Age-related changes in articular cartilage are likely to play a role in the aetiology of osteoarthritis (OA). One of the major age-related changes in cartilage is the accumulation of advanced-glycation-endproducts (AGEs). Since, cartilage tissue is not readily available from patients for studying AGE levels, alternative approaches such as analyzing skin and urine are needed to study the role of cartilage AGE levels in OA.

METHODS

Paired human skin and cartilage samples were obtained post mortem. Paired skin and urine samples were obtained from the CHECK cohort (early OA patients). Pentosidine levels were measured by high-performance liquid chromatography (HPLC). As marker of cumulative cartilage damage X-rays of both knees and hips were scored. Urinary CTXII (uCTXII) levels were measured, to assess current cartilage breakdown.

RESULTS

Cartilage and skin pentosidine correlate well (R=0.473, P=0.05). Skin pentosidine was higher in mild (summed (Kellgren & Lawrence K&L) over four large joints ≥4) compared to no (summed K&L≤3) radiographic OA (P=0.007). Urinary pentosidine was not different between these two groups. Skin pentosidine levels were not related to cartilage breakdown (highest vs lowest tertile of uCTXII). Urinary pentosidine, however, was higher in the highest compared to the lowest uCTXII tertile (P=0.009). Multiple regression analysis showed age to be the only predictor of the summed K&L score and age, creatinine clearance and urinary pentosidine as predictors of uCTXII.

CONCLUSION

The higher skin and urinary pentosidine levels in those with mild compared to no radiographic joint damage and low vs high cartilage breakdown respectively suggest that AGEs may contribute to disease susceptibility and/or progression. However, relations are weak and cannot be used as surrogate markers of severity of OA.

What are the best markers for disease progression in osteoarthritis (OA)?

To be able to prevent progression of osteoarthritis, the knowledge of prognostic factors of this progression is important. If certain prognostic factors are modifiable, they may enhance our ability to reduce osteoarthritis progression. Even if these prognostic factors are not modifiable, they can still be used to identify high-risk groups, which may have implications for patient information and the perspective of medical treatment. Prognostic factors of progression are reviewed here, mainly for hip and knee osteoarthritis as most data available concern these localisations. Areas of further research are highlighted.

First qualification study of serum biomarkers as indicators of total body burden of osteoarthritis

Background

Osteoarthritis (OA) is a debilitating chronic multijoint disease of global proportions. OA presence and severity is usually documented by x-ray imaging but whole body imaging is impractical due to radiation exposure, time and cost. Systemic (serum or urine) biomarkers offer a potential alternative method of quantifying total body burden of disease but no OA-related biomarker has ever been stringently qualified to determine the feasibility of this approach. The goal of this study was to evaluate the ability of three OA-related biomarkers to predict various forms or subspecies of OA and total body burden of disease.

Methodology/Principal Findings

Female participants (461) with clinical hand OA underwent radiography of hands, hips, knees and lumbar spine; x-rays were comprehensively scored for OA features of osteophyte and joint space narrowing. Three OA-related biomarkers, serum hyaluronan (sHA), cartilage oligomeric matrix protein (sCOMP), and urinary C-telopeptide of type II collagen (uCTX2), were measured by ELISA. sHA, sCOMP and uCTX2 correlated positively with total osteophyte burden in models accounting for demographics (age, weight, height): R² = 0.60, R² = 0.47, R² = 0.51 (all p<10⁻⁶); sCOMP correlated negatively with total joint space narrowing burden: R² = 0.69 (p<10⁻⁶). Biomarkers and demographics predicted 35–38% of variance in total burden of OA (total joint space narrowing or osteophyte). Joint size did not determine the contribution to the systemic biomarker concentration. Biomarker correlation with disease in the lumbar spine resembled that in the rest of the skeleton.

Conclusions/Significance

We have suspected that the correlation of systemic biomarkers with disease has been hampered by the inability to fully phenotype the burden of OA in a patient. These results confirm the hypothesis, revealed upon adequate patient phenotyping, that systemic joint tissue concentrations of several biomarkers can be quantitative indicators of specific subspecies of OA and of total body burden of disease.

Cartilage oligomeric matrix protein and hyaluronan levels in synovial fluid from horses with osteoarthritis of the tarsometatarsal joint compared to a control population

REASONS FOR PERFORMING STUDY

Quantification of cartilage oligomeric matrix protein (COMP) levels within synovial fluid from the tarsometatarsal joint has not previously been reported and an effective synovial fluid marker would allow monitoring of disease progression and treatment.

OBJECTIVES

To quantify levels of COMP and hyaluronan (HA) in synovial fluid from the tarsometatarsal joint, identify differences in levels from horses with osteoarthritis (OA) of the tarsometatarsal joint compared to a control population and to correlate levels with radiographic changes in horses with OA.

METHODS

Synovial fluid was collected from the tarsometatarsal joint of 25 horses without hindlimb lameness (controls) and 25 lame horses, subjected to analgesia of the joint. COMP concentrations were measured using a homologous inhibition ELISA. Immunoblots of synovial fluid from 3 lame horses and 3 controls were performed to identify fragmentation of COMP. Hyaluronan (HA) concentration in synovial fluid was determined using a competition ELISA. Radiographs of the lame horses with OA were scored and correlated with levels of COMP and HA.

RESULTS

Concentrations of COMP in OA of the tarsometatarsal joint were significantly lower than in the control samples. An additional fragment band of COMP (approximately 30 kDa) was identified on the immunoblots of the horses with OA and this fragment was not identified in controls. No significant difference was identified in the HA or HA:COMP ratio between lame and control horses. There was no correlation between levels of synovial fluid COMP and HA, and radiographic changes.

CONCLUSIONS AND POTENTIAL RELEVANCE

Lowered levels of COMP in synovial fluid of tarsometatarsal joints correlates with the presence of osteoarthritis. However, a single value cannot be used to stage the disease process. Levels of HA may not be a useful marker for this disease. Decreased, rather than increased COMP levels, may reflect significant loss of cartilage in established osteoarthritis. A specific assay for the COMP fragment generated with osteoarthritis may allow the earlier detection of clinical cases.

Glucosamine but not ibuprofen alters cartilage turnover in osteoarthritis patients in response to physical training

OBJECTIVE

To investigate changes in levels of serum cartilage oligomeric matrix protein (COMP) and urine c-telopeptide of type-2 collagen (CTX-II) as markers for cartilage turnover in patients with osteoarthritis (OA) of the knee, in response to muscle strength training in combination with treatment with glucosamine, ibuprofen or placebo.

DESIGN

A 12-week double blind, placebo controlled, randomized study.

METHOD

Thirty-six elderly patients with bilateral tibiofemoral knee OA determined by radiography were randomly assigned to treatment with glucosamine (n=12), ibuprofen (n=12) or placebo (n=12) during 12 weeks of strength training of both legs with focus on the quadriceps muscle. Strength tests (5 repetition maximum), blood and urine sampling were performed before and after the training period. Serum COMP and urinary CTX-II were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

All three groups increased their muscle strength following 12 weeks of strength training (P<0.001). Serum COMP levels were reduced in the glucosamine-treated group after the training period (P=0.012), whereas they did not change in the two other groups. Glucosamine reduced COMP statistically significant compared to both placebo and ibuprofen; the mean reduction with glucosamine was 13% vs placebo (P=0.0378) and 17% vs ibuprofen (P=0.0122). Urinary CTX-II levels did not change significantly in any of the three experimental groups.

CONCLUSION

Serum COMP decreased significantly over the 12-week training period when treatment with glucosamine was added to the training regimen. This suggests an effect by glucosamine on the response of the OA cartilage to a period of joint loading in humans with knee OA.

Serum hyaluronic acid as a potential marker with a predictive value for further radiographic progression of hand osteoarthritis

OBJECTIVE

To compare serum levels of hyaluronic acid (HA) between patients with erosive and non-erosive hand osteoarthritis (HOA), and investigate its association with morphological changes and radiographic progression over 2 years.

METHODS

Fifty-five women with erosive and 33 women with non-erosive HOA were included in this study. All underwent clinical examination, which included assessment of pain, swelling, deformity and deviation of small hand joints and completed health assessment questionnaires. Serum levels of HA were measured by ELISA. Three-phase bone scintigraphy was performed at baseline. Radiographs of both hands were performed at baseline and after 2 years and scored according Kallman grading scale.

RESULTS

Serum levels of HA were significantly higher in patients with erosive than with non-erosive HOA (P<0.01). It correlated significantly with the number of hand joints with deviations and deformities. HA adjusted for age and disease duration significantly correlated with radiographs at baseline and after 2 years in all patients with HOA (r=0.560 and r=0.542, P<0.01 for both correlations). Although there was an association between HA and radiographic score in erosive disease, after adjustment for confounders it remained no longer significant. HA adjusted for confounders correlated significantly with the late phase in all patients with HOA (r=0.412, P<0.01) and in patients with erosive disease (r=0.320, P<0.05).

CONCLUSION

HA is increased in patients with erosive HOA and could be proposed as a surrogate marker with a predictive value for further radiographic progression of HOA in general. Further investigation is necessary to confirm these results.

Prospective evaluation of serum biomarker levels and cartilage repair by autologous chondrocyte transplantation and subchondral drilling in a canine model

Introduction

The purpose of this study was to evaluate serum chondroitin sulfate (CS) and hyaluronic acid (HA) levels and the capability of cartilage repair of full-thickness cartilage defects after treatment with two different fundamental surgical techniques: autologous chondrocyte transplantation (AC) and subchondral drilling (SD).

Methods

A 4-mm-diameter full-thickness cartilage defect was created in each of 10 skeletally mature male outbred dogs. The dogs were randomly separated into two groups. Groups A and B were treated with AC and SD, respectively. An evaluation was made at the 24th week of the experiment. Serum was analyzed prospectively – preoperatively and at 6-week intervals – for CS and HA levels by enzyme-linked immunosorbent assay (ELISA) and ELISA-based assays, respectively.

Results

The cartilage repair assessment score (median ± standard deviation) of group A (9.5 ± 2.5) was significantly higher than that of group B (2.5 ± 1.3) (P < 0.05). Group A also demonstrated a better quality of hyaline-like cartilage repair. Prospective analysis of serum WF6 and HA levels between the two groups did not show any significant difference. Serum WF6 levels at the 24th week of the experiment had a negative correlation (r = -0.69, P < 0.05) with the cartilage repair assessment score, whereas serum HA levels tended to correlate positively (r = 0.46, 0.1 <P < 0.05).

Conclusions

AC treatment provides superior results to SD treatment, according to morphology, histology, and cartilage marker levels. AC treatment demonstrated a smoother surface, less fissure, better border integration, and a more reliable outcome of repairing cartilage. Moreover, a decreasing level of serum WF6, which correlated with good quality of the repairing tissue at the end of the follow-up period, was found predominantly in the AC group. Serum WF6 therefore should be further explored as a sensitive marker for the noninvasive therapeutic evaluation of cartilage repair procedures.

Relationship between Investigative Biomarkers and Radiographic Grading in Patients with Knee Osteoarthritis

Objective. To examine new investigative biomarkers and their relevance for radiographic severity in knee osteoarthritis. Methods. The group comprised 63 patients with 73 knees examined. Patients were divided according to radiographic severity to allow for comparison of biomarker levels. Hyaluronic acid (HA), matrix metalloproteases (MMP-1, MMP-3 and MMP-13), tissue inhibitors of metalloproteases (TIMP-1 and TIMP-2), platelet-derived growth factor (PDGF-AB), transformed growth factor (TGF-beta), vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and insulin-like growth factor (IGF-I) were measured on synovial fluid and in plasma releasate at a single time point. Principal component analysis (PCA) followed by analysis of covariance were applied to evaluate data. Results. Four different groups of biomarker were identified in plasma releasates. The first (platelet number, PDGF-AB and TGF-beta) and second groups (HA and IGF-I) were related to radiographic severity, P = .005 and P = .022, respectively. The third (MMP-1 and TIMP-2) and fourth groups (MMP-3 and TIMP-1) represented the catabolic balance, but were not associated to radiographic grading. Three different clusters of biomarkers were found in synovial fluid but did not show any significant association to radiographic grading. Conclusions. New imaging approaches to assess structural deterioration and correlation with biomarker levels are warranted to advance in OA research.

Chitinase 3-Like-1 (CHI3L1): a putative disease marker at the interface of proteomics and glycomics

Chitinase 3-Like-1 (CHI3L1) is a secreted 40 kDa glycoprotein that is upregulated in a number of human cancers and in non-neoplastic disease states characterized by chronic inflammation and tissue remodeling. Increased serum levels of CHI3L1 parallel disease severity, poorer prognosis, and shorter survival in many human neoplasias, including cancers of the breast, colon, prostate, ovaries, brain, thyroid, lung, and liver. Increased serum CHI3L1 also correlates with disease severity in rheumatoid arthritis, osteoarthritis, liver fibrosis, inflammatory bowel disease, and bacterial septicemia. CHI3L1 is a rheumatoid arthritis (RA) autoantigen, and MHC complexes containing specific CHI3L1 peptides have been found in RA patients; however, intranasal introduction of these same CHI3L1 peptides can induce tolerance towards them. CHI3L1 is a nonhydrolytic member of the human chitinase family that binds chitin tightly and heparin at lower affinity. Interactions with type I collagen, CHI3L1's only known protein-binding partner, helps regulate collagen fibril formation. The principal sources of CHI3L1 are activated macrophages and chondrocytes, neutrophils, and some tissue and tumor cells. CHI3L1 can act as a fibroblast mitogen and can activate several signaling pathways, however, no cell surface-binding partner for CHI3L1 has been identified. The ability of CHI3L1 to bind both proteins and carbohydrates allows potential interactions with a variety of cell-surface and extracellular-matrix proteins, proteoglycans, and polysaccharides, and thus CHI3L1 can interface between proteomics and glycomics.

Biomarkers in the development of novel disease-modifying therapies for osteoarthritis

Identification and utilization of biomarkers is vitally important for the successful development of disease-modifying osteoarthritis drugs. Biochemical and imaging platforms hold great promise to deliver such biomarkers. Studies indicate a marked increase in biochemical products arising from the breakdown and biosynthesis of collagen, extracellular matrix and bone in osteoarthritis. These molecules have been associated with disease severity and may also have prognostic value as indicators of disease progression. However, issues including biological variability and lack of tissue specificity currently hinder the utility of these molecular markers in drug development. Imaging technologies hold great potential for sensitive and accurate measurement of disease-related structural damage. Drawbacks, including expense, need for validation and limited accessibility also limit the utility of these technologies. In this article, the potential value and challenges in developing and utilizing biomarkers in disease-modifying osteoarthritis drug development will be discussed.