Effects of ibuprofen on molecular markers of cartilage and synovium turnover in patients with knee osteoarthritis

Different changes in the biomarker C-terminal telopeptides of type II collagen (CTX-II) following intra-articular injection of high molecular weight hyaluronic acid and oral non-steroidal anti-inflammatory drugs in patients with knee osteoarthritis: a multi-center randomized controlled study

OBJECTIVES

We previously reported, based on a multicenter randomized-control study, that the efficacy of intra-articular injections of hyaluronic acid (IA-HA) was not inferior to that of oral non-steroidal anti-inflammatory drugs (NSAIDs) in patients with knee osteoarthritis (OA). However, the molecular effects on the pathophysiology of knee OA remain unclear. C-terminal telopeptides of type II collagen (CTX-II) is reported to primarily originate from the interface between articular cartilage and subchondral bone, which is a site of potential remodeling in OA. We performed a predefined sub-analysis of the previous study to compare the changes of urinary CTX-II (uCTX-II) in response to IA-HA to those in response to NSAID for knee OA.

DESIGN

A total of 200 knee OA patients were registered from 20 hospitals and randomized to receive IA-HA (2,700 kDa HA, 5 times at 1-week intervals) or NSAID (loxoprofen sodium, 180 mg/day) for 5 weeks. The uCTX-II levels were measured before and after treatment.

RESULTS

The uCTX-II levels were significantly increased by IA-HA treatment (337.7 ± 193.8 to 370.7 ± 234.8 ng/μmol Cr) and were significantly reduced by NSAID treatment (423.2 ± 257.6 to 370.3 ± 250.9 ng/μmol Cr). The %changes of uCTX-II induced by IA-HA (11.6 ± 29.5%) and NSAID (-9.0 ± 26.7%) was significantly different (between-group difference: 20.6, 95% confidence intervals: 10.6 to 30.6).

CONCLUSIONS

While both IA-HA and NSAID improved symptoms of knee OA, uCTX-II levels were increased by IA-HA and reduced by NSAIDs treatment, suggesting these treatments may improve symptoms of knee OA through different modes of action.

Poly beta amino ester coated emulsions of NSAIDs for cartilage treatment

Delivering drugs directly into cartilage is still the major challenge in the management and treatment of osteoarthritis (OA) resulting from the aneural, avascular and alymphatic nature of an articular cartilage structure. Progress has been made in the design of drug delivery systems that enhance corticosteroid uptake and retention in cartilage; however also non-steroidal anti-inflammatory drugs (NSAIDs) are prescribed for patients affected by OA and a drug delivery system specifically designed for this drug category is currently unavailable. We developed an approach based on the preparation of NSAID oil-in-water emulsions coated with poly-beta-amino-esters (PBAEs) to exploit the cartilage penetrating ability of such polymers and the high solubility of drugs in oil. These emulsions containing different NSAIDs (indomethacin, ketorolac, diclofenac and naproxen) exhibited enhanced and prolonged drug localisation not only in healthy cartilage tissues but also in early-stage OA samples. The critical role of the PBAE layer on oil droplets was established along with the retained biological activity of the drug as glycosaminoglycan (GAG) and collagen degradation induced by interleukin-1 (IL-1) was prevented by the novel technology. Oil-in-water coated emulsions are very flexible and cost-effective drug delivery systems and such an approach presented here could provide a substantial improvement in the therapeutic treatments of OA and thus patients' outcomes.

Treatment response in dogs with naturally occurring grade 3 elbow osteoarthritis following intra-articular injection of 117mSn (tin) colloid

The radionuclide ^117mSn (tin-117m) embedded in a homogeneous colloid is a novel radiosynoviorthesis (RSO) device for intra-articular (IA) administration to treat synovial inflammation and mitigate osteoarthritis (OA) in dogs. A study to evaluate tin-117m colloid treatment response in dogs with OA was conducted at two centers, the School of Veterinary Medicine at Louisiana State University, and at a referral practice in Houston, Texas. The tin-117m colloid was administered per-protocol to 14 client-owned dogs with radiographically confirmed, grade 3 OA in one or both elbow joints. Dog owners and attending clinicians assessed the level of pain at baseline (BL) and the post-treatment pain response at 90-day intervals for one year. Owners assessed treatment response according to a pain severity score (PSS) and a pain interference score (PIS) as defined by the Canine Brief Pain Inventory. Clinicians reported a lameness score using a 0–5 scale, from no lameness to continuous non-weight bearing lameness, when observing dogs at a walk and a trot. The rate of treatment success as determined by improved mean PSS and PIS scores reported by dog owners was >70% at all time points. Clinicians reported an improved mean pain score from BL at post-treatment Days 90 (p<0.05), 180, and 270. The dog owner and clinician assessments of treatment success were significantly correlated (p>0.05) at Day 90 and Day 180 time points. Results indicated that a single IA dose of tin-117m colloid provided a significant reduction in pain and lameness and improved functionality for up to a full year, with no adverse treatment related effects, in a high percentage of dogs with advanced, clinical OA of the elbow joint.

Prostaglandin E2 induces dual-specificity phosphatase-1, thereby attenuating inflammatory genes expression in human osteoarthritic synovial fibroblasts

Characteristic features of osteoarthritis (OA) are joint pain and cartilage degeneration. The degeneration is caused by excess induction of matrix metalloproteinases (MMPs) and the pain is caused by nerve growth factor (NGF)-dependent nerve invasion into synovial tissue in addition to nociceptive pain by prostaglandin (PG)E_2. The objective of this study was to clarify the suppressive mechanism of PGE₂ on the regulation of MMPs and NGF by focusing on mitogen-activated protein kinases (MAPKs) and their endogenous phosphatase, dual-specificity phosphatase (DUSP)-1 in human synovial fibroblasts. PGE₂ strongly increased DUSP-1 and suppressed IL-1β-induced MAPKs phosphorylation. Inhibition of MAPKs by selective inhibitors differentially regulated the IL-1β-induced expression of MMPs and NGF expression. IL-1β-induced MAPKs phosphorylation was prolonged and enhanced in DUSP-1 knockdown cells and the expression of MMPs and NGF was also increased. This study revealed that PGE₂ has novel biological activity that suppresses NGF and MMPs expression by inducing DUSP-1 expression.

Pain characteristics and biomarkers in treatment approaches for osteoarthritis pain

Osteoarthritis (OA) is a progressive disease and OA pain intensity is related to ongoing pathophysiological changes. However, OA pain is complex and multimodal; its characteristics, including severity, localization and the stimuli that elicit it, can change as the disease progresses and differ greatly among patients. Understanding mechanisms underlying specific pain characteristics may help guide clinicians in choosing appropriate treatments, targeting treatments to those patients most likely to benefit. Associations have been demonstrated between biomarkers and some characteristics of OA pain, and to processes linked to the shift in pain characteristics over the course of OA. This article examines how understanding OA pain characteristics and their relation to the disease process could inform treatment choice when applying well-established treatment guidelines.

Dose-dependent roles of aspirin and other non-steroidal anti-inflammatory drugs in abnormal bone remodeling and skeletal regeneration

The failure of remodeling process that constantly regenerates effete, aged bone is highly associated with bone nonunion and degenerative bone diseases. Numerous studies have demonstrated that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) activate cytokines and mediators on osteoclasts, osteoblasts and their constituent progenitor cells located around the remodeling area. These cells contribute to a complex metabolic scenario, resulting in degradative or synthetic functions for bone mineral tissues. The spatiotemporal effects of aspirin and NSAIDs in the bone remodeling are controversial according the specific therapeutic doses used for different clinical conditions. Herein, we review in vitro, in vivo, and clinical studies on the dose-dependent roles of aspirin and NSAIDs in bone remodeling. Our results show that low-dose aspirin (< 100 μg/mL), which is widely recommended for prevention of thrombosis, is very likely to be benefit for maintaining bone mass and qualities by activation of osteoblastic bone formation and inhibition of osteoclast activities via cyclooxygenase-independent manner. While, the roles of high-dose aspirin (150-300 μg/mL) and other NSAIDs in bone self-regeneration and fracture-healing process are difficult to elucidate owing to their dual effects on osteoclast activity and bone formation of osteoblast. In conclusion, this study highlighted the potential clinical applications of low-dose aspirin in abnormal bone remodeling as well as the risks of high-dose aspirin and other NSAIDs for relieving pain and anti-inflammation in fractures and orthopedic operations.

Defining acute flares in knee osteoarthritis: a systematic review

OBJECTIVE

To identify and critically synthesise definitions of acute flares in knee osteoarthritis (OA) reported in the medical literature.

DESIGN

Systematic review and narrative synthesis. We searched Medline, EMBASE, Web of science and six other electronic databases (inception to July 2017) for original articles and conference abstracts reporting a definition of acute flare (or synonym) in humans with knee OA. There were no restrictions by language or study design (apart from iatrogenic-induced flare-ups, eg, injection-induced). Data extraction comprised: definition, pain scale used, flare duration or withdrawal period, associated symptoms, definition rationale, terminology (eg, exacerbation or flare), baseline OA severity, age, gender, sample size and study design.

RESULTS

Sixty-nine articles were included (46 flare design trials, 17 observational studies, 6 other designs; sample sizes: 15-6085). Domains used to define flares included: worsening of signs and symptoms (61 studies, 27 different measurement tools), specifically increased pain intensity; minimum pain threshold at baseline (44 studies); minimum duration (7 studies, range 8-48 hours); speed of onset (2 studies, defined as 'sudden' or 'quick'); requirement for increased medication (2 studies). No definitions included activity interference.

CONCLUSIONS

The concept of OA flare appears in the medical literature but most often in the context of flare design trials (pain increases observed after stopping usual treatment). Key domains, used to define acute events in other chronic conditions, appear relevant to OA flare and could provide the basis for consensus on a single, agreed definition of 'naturally occurring' OA flares for research and clinical application.

PROSPERO REGISTRATION NUMBER

CRD42014010169.

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

OBJECTIVE

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Does long term colchicine prevent degradation of collagen fiber network in osteoarthritis?

AIM

Several studies have shown that colchicine exhibits an improvement in the symptoms of knee osteoarthritis (OA) but its effect on disease progression is unknown. To clarify the mechanism of action this study was done to see if colchicine prevents degradation of collagen fiber network in OA by studying serum cartilage oligomeric matrix protein (COMP) levels, a marker of cartilage turnover, over a period of 1 year.

METHODS

Seventy-five patients received colchicine plus paracetamol and 75 received placebo alone for the same time period. Serum COMP assays were done at baseline, 2 months and 1 year by enzyme-linked immunosorbent assay. These markers were compared between visits using repeated measures analysis of variance.

RESULTS

Serum COMP levels in the paracetamol-alone group did not show significant change between baseline and 2 months; however, there was a significant increase in serum COMP levels from 2 months to 1 year, suggesting increased uncoupling of proteoglycans from collagen and disease progression. No such change was seen in the colchicine group, signifying lack of progression of disease in this group.

CONCLUSION

Colchicine may act as a disease-modifying agent in OA.

Meniscal biology in health and disease

The knee is a fascinating yet complex joint. Researchers and clinicians agree that the joint is an organ comprised of highly specialized intrinsic and extrinsic tissues contributing to both health and disease. Key to the function and movement of the knee are the menisci, exquisite fibrocartilage structures that are critical structures for maintaining biological and biomechanical integrity of the joint. The biological/physiological functions of the menisci must be understood at the tissue, cellular and even molecular levels in order to determine clinically relevant methods for assessing it and influencing it. By investigating normal and pathological functions at the basic science level, we can begin to translate data to patients. The objective of this article is to provide an overview of this translational pathway so that progression toward improved diagnostic, preventative, and therapeutic strategies can be effectively pursued. We have thoroughly examined the pathobiological, biomarker, and imaging aspects of meniscus research. This translational approach can be effective toward optimal diagnosis, prevention, and treatment for the millions of patients who suffer from meniscal disorders each year.

Effect of mud compress therapy on cartilage destruction detected by CTX-II in patients with knee osteoarthritis

BACKGROUND/OBJECTIVE

The aim of this study is to investigate the effect of mud compress (MC) therapy compared to hot pack (HP) therapy on cartilage destruction and subchondral bone alterations detected by urine levels of C telopeptide fragment of collagen type-II (uCTX-II) in patients with knee osteoarthritis (OA).

METHODS

Fifty-nine patients between 49-74 years of age with bilateral knee OA divided into 2 groups. Twenty-five patients (16 females, 9 males) and 34 patients (22 females, 13 males) were given HP versus local natural organic and mineral-rich MC therapy respectively for 2 weeks as a total of 12 sessions. uCTX-II, Visual Analog Scale (VAS), 15 m walking time, Western Ontario and McMaster Universities multifunctional (WOMAC) index were measured at baseline, after-treatment and 3 months after treatment.

RESULTS

uCTX-II level did not show any difference between the two groups, however it decreased significantly in MC and HP groups 3 months after treatment (p< 0.017). WOMAC stiffness sore was significantly lower in MC group 3 months after treatment (p< 0.05). Both MC and HP therapies lowered VAS, WOMAC total and subscores significantly up to 3 months (p< 0.017).

CONCLUSIONS

HP and MC therapies for OA of knee are not superior to one another with respect to the level of uCTX-II. MC may probably decrease the ongoing cartilage destruction and related subchonral bone interactions earlier compared to HP treatment in patients with knee OA as evidenced by decreased uCTX-II levels after-treatment.

Predictive validity of biochemical biomarkers in knee osteoarthritis: data from the FNIH OA Biomarkers Consortium

OBJECTIVE

To investigate a targeted set of biochemical biomarkers as predictors of clinically relevant osteoarthritis (OA) progression.

METHODS

Eighteen biomarkers were measured at baseline, 12 months (M) and 24 M in serum (s) and/or urine (u) of cases (n=194) from the OA initiative cohort with knee OA and radiographic and persistent pain worsening from 24 to 48 M and controls (n=406) not meeting both end point criteria. Primary analyses used multivariable regression models to evaluate the association between biomarkers (baseline and time-integrated concentrations (TICs) over 12 and 24 M, transposed to z values) and case status, adjusted for age, sex, body mass index, race, baseline radiographic joint space width, Kellgren-Lawrence grade, pain and pain medication use. For biomarkers with adjusted p<0.1, the c-statistic (area under the curve (AUC)), net reclassification index and the integrated discrimination improvement index were used to further select for hierarchical multivariable discriminative analysis and to determine the most predictive and parsimonious model.

RESULTS

The 24 M TIC of eight biomarkers significantly predicted case status (ORs per 1 SD change in biomarker): sCTXI 1.28, sHA 1.22, sNTXI 1.25, uC2C-HUSA 1.27, uCTXII, 1.37, uNTXI 1.29, uCTXIα 1.32, uCTXIβ 1.27. 24 M TIC of uCTXII (1.47-1.72) and uC2C-Human Urine Sandwich Assay (HUSA) (1.36-1.50) both predicted individual group status (pain worsening, joint space loss and their combination). The most predictive and parsimonious combinatorial model for case status consisted of 24 M TIC uCTXII, sHA and sNTXI (AUC 0.667 adjusted). Baseline uCTXII and uCTXIα both significantly predicted case status (OR 1.29 and 1.20, respectively).

CONCLUSIONS

Several systemic candidate biomarkers hold promise as predictors of pain and structural worsening of OA.

Pain reduction with oral methotrexate in knee osteoarthritis, a pragmatic phase iii trial of treatment effectiveness (PROMOTE): study protocol for a randomized controlled trial

Background

Osteoarthritis (OA) is the fastest growing cause of disability worldwide. Current treatments for OA are severely limited and a large proportion of people with OA live in constant, debilitating pain. There is therefore an urgent need for novel treatments to reduce pain. Synovitis is highly prevalent in OA and is associated with pain. In inflammatory arthritides such as rheumatoid arthritis, methotrexate (MTX) is the gold standard treatment for synovitis and has a well-known, acceptable toxicity profile. We propose that using MTX to treat patients with symptomatic knee OA will be a practical and safe treatment to reduce synovitis and, consequently, pain.

Methods/Design

Pain Reduction with Oral Methotrexate in knee Osteoarthritis, a pragmatic phase III trial of Treatment Effectiveness (PROMOTE) is an investigator-initiated, multi-centre, randomized, double-blind, pragmatic placebo-controlled trial. A total of 160 participants with symptomatic knee OA will be recruited across primary and secondary care sites in the United Kingdom and randomized on a 1:1 basis to active treatment or placebo, in addition to usual care, for 12 months. As is usual practice for MTX, dosing will be escalated over six weeks to 25 mg (or maximum tolerated dose) weekly for the remainder of the study. The primary endpoint is change in average knee pain during the past week (measured on an 11-point numerical rating scale) between baseline and six months. Secondary endpoints include other self-reported pain, function and quality-of-life measures. A health economics analysis will also be performed. A magnetic resonance imaging substudy will be conducted to provide an explanatory mechanism for associated symptom change by examining whether MTX reduces synovitis and whether this is related to symptom change. Linear and logistic regression will be used to compare changes between groups using univariable and multivariable modelling analyses. All analyses will be conducted on an intention-to-treat basis.

Discussion

The PROMOTE trial is designed to examine whether MTX is an effective analgesic treatment for OA. The MRI substudy will address the relationship between synovitis and symptom change. This will potentially provide a much needed new treatment for knee OA.

Trial registration

Current Controlled Trials identifier: ISRCTN77854383 (registered: 25 October 2013).

Evaluation of the anti-inflammatory/chondroprotective activity of aldose reductase inhibitors in human chondrocyte cultures

2-Thioxo-4-thiazolidinone derivatives active as aldose reductase inhibitors were able to control key inflammatory/degenerative events induced by IL-1β in human chondrocytes, appearing to be promising candidates in the search for novel anti-inflammatory agents.

In vitro evaluation of S-(+)-ibuprofen as drug candidate for intra-articular drug delivery system

Intra-articular drug delivery systems (DDSs) are envisaged as interesting alternative to locally release non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to reduce pain in patients with osteoarthritis. The present study examines the efficacy of S-(+)-ibuprofen on cartilage degradation as drug candidate for DDS loading. Humeral cartilage and joint capsule explants were collected from healthy sheep shoulder joints and they were cultured in mono- or in co-culture for 13 days with LPS in combination with S-(+)-ibuprofen at 50 µM and 1 mM. S-(+)-ibuprofen (50 µM) blocked prostaglandins production in LPS-activated explants but did not reduce cartilage degradation. By contrast, 1 mM S-(+)-ibuprofen treatment of cartilage explants reduced nitric oxide synthesis by 51% (p = 0.0072), proteoglycans degradation by 35% (p = 0.0114) and expression of serum amyloid protein - the main protein induced upon LPS challenge - by 44% (p < 0.0001). On contrary, in presence of synovial membrane, the protective effects of S-(+)-ibuprofen on cartilage damages were significantly diminished. At 1mM, S-(+)-ibuprofen reduced the cell lysis during culture of cartilage and joint capsule either in mono- or in co-culture. This study performed on sheep explants shows that 1 mM S-(+)-ibuprofen inhibited cartilage degradation via a mechanism independent of cyclooxygenase inhibition. Reduction of prostaglandins synthesis at 50 µM in all treatment groups and reduction of cartilage degradation observed at 1 mM suggest that S-(+)-ibuprofen could be considered as a promising drug candidate for the loading of intra-articular DDS.

Efficacy of treatment with glucosamine sulfate in patients with knee effusion due to osteoarthritis

OBJECTIVE

Evaluation of anti-inflammatory effect of Glucosamine sulfate (GS) versus diclofenac sodium (DS) in effusion of osteoarthritic knees.

METHODOLOGY

In this study, patients were included in this study from 2007-2010 based on American College of Rheumatology criteria with OA and physical examination in effusion of osteoarthritic knees. The patients were divided into two groups. First group (27 patients) DS was given in doses 75 mg twice daily for ten day. In the group II (25 patients) GS was used in doses of 1500 mg two times daily over the first 12 weeks of the study. A closed aspiration was performed. The knee circumference was measured in patients before and 12 week after treatment. Before and after 12 weeks of treatments, both groups of patients were assessed according to the WOMAC questionnaire of knee pain and function scores.

RESULTS

Comparison of knee mean circumference between the two groups was not statistically significant before treatment (p=0.938), but significant after treatment (p<0.001). At the end of the 12 week, there was 66.6% complete resolution of effusion in the DS group (18 patients) and 24.0% (6 patients) in the GS group, this was statistically significant (P<0.001). DS groups, results of the beginning and at the end of 12 week measurement showed significant differences in WOMAC pain mean score (P < 0.001) but GS groups not statistically significant (P=0.160). The WOMAC function mean scores in pre and post-treatment periods of follow-up showed significant variation between the two groups (P< 0.001, P<0.001).

CONCLUSIONS

Our observations suggest that GS is not able to suppress the progression of adjuvant arthritis in OA with effusion of knee osteoarthritis. GS should not be expected as anti-inflammatory influence as DF in the treatment of OA-related effusion.

The pathogenesis of osteoarthritis involves bone, cartilage and synovial inflammation: may estrogen be a magic bullet?

The female predominance of polyarticular osteoarthritis (OA), and in particular the marked increase of OA in women after the menopause points to a likely involvement of female sex hormones in the maintenance of cartilage homeostasis. This perception has inspired many research groups to investigate the role of estrogens in the modulation of cartilage homeostasis with the ultimate aim to clarify whether estrogen replacement therapy (ERT) could provide benefits in preventing the rapid rise in the prevalence of OA in postmenopausal women. The effects of ERT and selective estrogen-receptor modulators on the joint in various experimental models have been investigated. Clinically, the effects of estrogens have been evaluated by post hoc analysis in clinical trials using biochemical markers of cartilage and bone degradation. Lastly, the Women's Health Initiative trial (WHI) investigated the effects of estrogens on the joint and joint replacements. Even though the exact mode of action still needs to be elucidated, the effect involves both direct and indirect mechanisms on the whole joint pathophysiology. Several animal models have demonstrated structural benefits of estrogens, as well as significant effects on joint inflammation. This is in complete alignment with clinical data using biochemical markers of joint degradation which demonstrated approximately 50% inhibition of cartilage destruction. These finding were recently validated in WHI, where women taking estrogens had significantly less joint replacement. In conclusion, the pleiotropic effect of estrogens on several different tissues may match the complicated aetiology of OA in some important aspects.

The role of synovitis in osteoarthritis

Osteoarthritis (OA) is the most common form of arthritis worldwide yet there is still a lack of effective treatments for this condition. Increasingly, attention has turned to the role of the synovium in OA as it is now recognized, in part from the use of modern imaging techniques, that synovitis is both common and associated with pain. This offers a target for treatment, for both symptom and potential structure modification. In this review we discuss the evidence for histological and imaging-detected synovitis and the current role of antisynovial therapies in OA.

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".

Osteoarthritis of the knee and hip. Part II: therapy with ibuprofen and a review of clinical trials

OBJECTIVES

We review the pharmacological properties and clinical evidence pertaining to the efficacy of ibuprofen as a first-line treatment in hip and knee osteoarthritis (OA). In the context of our previous paper's exploration of the aetiology and pathogenesis of OA as a basis for pharmacotherapy, we discuss the pharmacokinetics (PK) and clinical pharmacodynamics (PD) of ibuprofen relevant to OA.

KEY FINDINGS

Although widely used, the benefits and risks of ibuprofen, especially compared with other non-steroidal anti-inflammatory drugs (NSAIDs) and placebo, have only recently been evaluated in OA of the hip and knee in randomized-controlled clinical trials (RCT). The efficacy and occurrence of adverse reactions from ibuprofen was compared with placebo in a structural review of the literature and systematic review of RCTs in large-scale clinical trials. Ibuprofen has been found to result in approximately 50-60% improvement over placebo in WOMAC scores, including those reflecting inflammatory joint pain in knee and hip OA or other indices of pain, disability and impaired function. Mega-trials performed in comparison with the newer NSAIDs, the coxibs, have shown that ibuprofen has comparable therapeutic benefits and although serious gastrointestinal conditions are sometimes more frequent after short-term treatment, longer-term (several months) therapy in OA reduces the advantages of the coxibs over other NSAIDs including ibuprofen. Cardiovascular risk, though present with coxibs and some NSAIDs in OA, is lower or slightly so with ibuprofen compared with coxibs.

SUMMARY

Ibuprofen is effective and relatively safe (especially at low over-the-counter doses and in the short term) for mild-to-moderate OA of the knee and hip. The PK properties of ibuprofen in OA (short plasma t½) confer advantages of this drug for OA, while evidence for clinically relevant PD benefits in joints of patients with OA, though limited, is suggestive of local anti-inflammatory activity.

Application of biomarkers in the development of drugs intended for the treatment of osteoarthritis

OBJECTIVE

Osteoarthritis (OA) is a chronic and slowly progressive disease for which biomarkers may be able to provide a more rapid indication of therapeutic responses to therapy than is currently available; this could accelerate and facilitate OA drug discovery and development programs. The goal of this document is to provide a summary and guide to the application of in vitro (biochemical and other soluble) biomarkers in the development of drugs for OA and to outline and stimulate a research agenda that will further this goal.

METHODS

The Biomarkers Working Group representing experts in the field of OA biomarker research from both academia and industry developed this consensus document between 2007 and 2009 at the behest of the Osteoarthritis Research Society International Federal Drug Administration initiative (OARSI FDA initiative).

RESULTS

This document summarizes definitions and classification systems for biomarkers, the current outcome measures used in OA clinical trials, applications and potential utility of biomarkers for development of OA therapeutics, the current state of qualification of OA-related biomarkers, pathways for biomarker qualification, critical needs to advance the use of biomarkers for drug development, recommendations regarding practices and clinical trials, and a research agenda to advance the science of OA-related biomarkers.

CONCLUSIONS

Although many OA-related biomarkers are currently available they exist in various states of qualification and validation. The biomarkers that are likely to have the earliest beneficial impact on clinical trials fall into two general categories, those that will allow targeting of subjects most likely to either respond and/or progress (prognostic value) within a reasonable and manageable time frame for a clinical study (for instance within 1-2 years for an OA trial), and those that provide early feedback for preclinical decision-making and for trial organizers that a drug is having the desired biochemical effect. As in vitro biomarkers are increasingly investigated in the context of specific drug treatments, advances in the field can be expected that will lead to rapid expansion of the list of available biomarkers with increasing understanding of the molecular processes that they represent.

Joint inflammation and early degeneration induced by high-force reaching are attenuated by ibuprofen in an animal model of work-related musculoskeletal disorder

We used our voluntary rat model of reaching and grasping to study the effect of performing a high-repetition and high-force (HRHF) task for 12 weeks on wrist joints. We also studied the effectiveness of ibuprofen, administered in the last 8 weeks, in attenuating HRHF-induced changes in these joints. With HRHF task performance, ED1+ and COX2+ cells were present in subchondral radius, carpal bones and synovium; IL-1alpha and TNF-alpha increased in distal radius/ulna/carpal bones; chondrocytes stained with Terminal deoxynucleotidyl Transferase- (TDT-) mediated dUTP-biotin nick end-labeling (TUNEL) increased in wrist articular cartilages; superficial structural changes (e.g., pannus) and reduced proteoglycan staining were observed in wrist articular cartilages. These changes were not present in normal controls or ibuprofen treated rats, although IL-1alpha was increased in reach limbs of trained controls. HRHF-induced increases in serum C1,2C (a biomarker of collagen I and II degradation), and the ratio of collagen degradation to synthesis (C1,2C/CPII; the latter a biomarker of collage type II synthesis) were also attenuated by ibuprofen. Thus, ibuprofen treatment was effective in attenuating HRHF-induced inflammation and early articular cartilage degeneration.

Anti-inflammatory effect of low-level laser and light-emitting diode in zymosan-induced arthritis

OBJECTIVE

The aim of this work was to investigate the effect of low-level laser therapy (LLLT) and light-emitting diode (LED) on formation of edema, increase in vascular permeability, and articular joint hyperalgesia in zymosan-induced arthritis.

BACKGROUND DATA

It has been suggested that low-level laser and LED irradiation can modulate inflammatory processes.

MATERIAL AND METHODS

Arthritis was induced in male Wistar rats (250-280 g) by intra-articular injection of zymosan (1 mg in 50 microL of a sterile saline solution) into one rear knee joint. Animals were irradiated immediately, 1 h, and 2 h after zymosan administration with a semiconductor laser (685 nm and 830 nm) and an LED at 628 nm, with the same dose (2.5 J/cm(2)) for laser and LED. In the positive control group, animals were injected with the anti-inflammatory drug dexamethasone 1 h prior to the zymosan administration. Edema was measured by the wet/dry weight difference of the articular tissue, the increase in vascular permeability was assessed by the extravasation of Evans blue dye, and joint hyperalgesia was measured using the rat knee-joint articular incapacitation test.

RESULTS

Irradiation with 685 nm and 830 nm laser wavelengths significantly inhibited edema formation, vascular permeability, and hyperalgesia. Laser irradiation, averaged over the two wavelengths, reduced the vascular permeability by 24%, edema formation by 23%, and articular incapacitation by 59%. Treatment with LED (628 nm), with the same fluence as the laser, had no effect in zymosan-induced arthritis.

CONCLUSION

LLLT reduces inflammatory signs more effectively than LED irradiation with similar irradiation times (100 sec), average outputs (20 mW), and energy doses (2 J) in an animal model of zymosan-induced arthritis. The anti-inflammatory effects of LLLT appear to be a class effect, which is not wavelength specific in the red and infrared parts of the optical spectrum.

In vivo effects of meloxicam on inflammatory mediators, MMP activity and cartilage biomarkers in equine joints with acute synovitis

REASONS FOR PERFORMING STUDY

Meloxicam is a commonly used nonsteroidal anti-inflammatory drug in equine practice, but little is known about its in vivo effects on joint inflammation and cartilage turnover.

OBJECTIVES

To study the effects of meloxicam on biomarkers of inflammation, matrix metalloproteinase (MMP) activity, and cartilage biomarkers in joints with experimental synovitis.

METHODS

In a 2-period cross-over study, synovitis was induced at T = 0 h in the L or R intercarpal joint of 6 horses by intraarticular injection of 0.5 ng lipopolysaccharide (LPS). Horses received once daily meloxicam (0.6 mg/kg bwt per os) or placebo starting at post injection hour (PIH) 2, and clinical evaluations as well as blood and synovial fluid (SF) sampling were performed at PIH 0, 8, 24 and 168. Synovial fluid was analysed for prostaglandin E2, bradykinin, substance P, general MMP activity, glycosaminoglycans (GAG), CS846 epitope, type II collagen cleavage fragments (C2C) and type II collagen carboxypropeptide (CPII). Concentrations in meloxicam- vs. placebo-treated joints over time were compared using a linear mixed model.

RESULTS

Lipopolysaccharide injection caused marked transient synovitis without systemic effects. Meloxicam caused a significant reduction in lameness at PIH 8 and 24 and tended to reduce effusion. In addition, meloxicam significantly suppressed SF prostaglandin E2 and substance P release at PIH 8 and bradykinin at PIH 24 compared to placebo treatment. General MMP activity at PIH 8 and 24 was significantly lower in meloxicam- vs. placebo-treated joints, as were GAG, C2C and CPII concentrations at PIH 24.

CONCLUSIONS

Acute transient synovitis leads to substantial increases in SF biomarkers of inflammation, MMP activity and cartilage turnover, which can be significantly suppressed by meloxicam.

POTENTIAL RELEVANCE

Early oral treatment with meloxicam ameliorates not only clinical signs and joint inflammation in acute synovitis, but may also limit inflammation-induced cartilage catabolism.

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.

Is osteoarthritis a heterogeneous disease that can be stratified into subsets?

Osteoarthritis is a heterogeneous disease characterized by variable clinical features, biochemical/genetic characteristics, and responses to treatments. To optimize palliative effects of current treatments and develop efficacious disease-modifying interventions, treatments may need to be tailored to the individual or a subset of osteoarthritic joints. The purpose of this review is to explore the current literature on the clinical and physiological variability in osteoarthritis and potential for stratifying patients. Several stratifications have been reported, including mechanism of onset, stage of disease progression, involved joints, inflammatory levels, and effusion. Most of these methods revealed two to three unique subsets of osteoarthritis. Osteoarthritic joints may be stratified by an array of variables, some transient and others consistent throughout the disease process. Future research needs to continue to explore stratification techniques since these may be the key to optimizing palliative interventions and developing disease-modifying interventions for subsets within this heterogeneous disease.

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.

Application of biomarkers in the clinical development of new drugs for chondroprotection in destructive joint diseases: a review

Emerging evidence supports the concept that biochemical markers are clinically useful non-invasive diagnostic tools for the monitoring of changes in cartilage turnover in patients with destructive joint diseases such as osteoarthritis (OA) and rheumatoid arthritis (RA). Epidemiological studies demonstrated that measurements of different degradation products of proteins in the extracellular matrix of hyaline cartilage in urine or serum samples are (1) increased in OA or RA patients compared with healthy individuals, (2) correlate with disease activity, and (3) are predictive for the rate of changes in radiographic measures of cartilage loss. The present review provides an updated list of available biomarkers and summarize the research data arguing for their clinical utility. In addition, it addresses the question whether or not the monitoring of biomarkers during different treatment modalities could be a useful approach to characterize the chondro-protective effects of approved and candidate drugs. Finally, it briefly reviews the in vitro/ex vivo experimental settings - isolated chondrocyte cultures and articular cartilage explants - that can assist in the verification of novel markers, but also studies assessing direct effects of drug candidates on chondrocytes. Collectively, biomarkers may acquire a function as established efficacy parameters in the clinical development of novel chondro-protective agents.

Cartilage in normal and osteoarthritis conditions

The preservation of articular cartilage depends on keeping the cartilage architecture intact. Cartilage strength and function depend on both the properties of the tissue and on their structural parameters. The main structural macromolecules are collagen and proteoglycans (aggrecan). During life, cartilage matrix turnover is mediated by a multitude of complex autocrine and paracrine anabolic and catabolic factors. These act on the chondrocytes and can lead to repair, remodeling or catabolic processes like those that occur in osteoarthritis. Osteoarthritis is characterized by degradation and loss of articular cartilage, subchondral bone remodeling, and, at the clinical stage of the disease, inflammation of the synovial membrane. The alterations in osteoarthritic cartilage are numerous and involve morphologic and metabolic changes in chondrocytes, as well as biochemical and structural alterations in the extracellular matrix macromolecules.

Can biochemical markers serve as surrogates for imaging in knee osteoarthritis?

OBJECTIVE

Osteoarthritis (OA) is a complex heterogeneous joint disease affecting more than 35 million people worldwide. The current gold standard diagnostic investigation is the plain radiograph, which lacks sensitivity. Biochemical markers have the potential to act as adjunct markers for imaging in the assessment of knee OA. We undertook this study to determine the association between individual biochemical markers and radiographic features, and to establish whether the association is strengthened when selected biochemical markers are combined into a single factor (a theoretical marker).

METHODS

Twenty serum and urinary biochemical markers were analyzed in 119 patients with predominantly tibiofemoral knee OA. Pearson's correlation was performed, and corresponding coefficients of determination (R(2)) were calculated to determine the association between biochemical markers and a range of imaging features from radiographs and dual x-ray absorptiometry of the knee. Biochemical markers demonstrating a significant association (P < 0.05) with a specific imaging feature were combined by principal components analysis (PCA). Pearson's correlation was repeated to establish whether the combined panel of biochemical markers showed a stronger association with imaging than the best single marker.

RESULTS

Fourteen biochemical markers showed significant associations with one or more imaging features. By combining specific panels of biochemical markers to form factors, the association of markers with imaging features (R(2)) increased from 11.9% to 22.7% for the Kellgren/Lawrence (K/L) score, from 5.9% to 9.2% for joint space width (JSW), from 6.6% to 10.8% for sclerosis, from 13.5% to 22.6% for osteophytes, and from 12.0% to 14.2% for bone mineral density (BMD). Biochemical markers identifying patients with osteophytes overlapped with those correlated with a high K/L score, while markers of subchondral BMD formed a completely separate group. Biochemical markers of JSW included markers associated with both osteophytes and BMD.

CONCLUSION

The PCA results suggest that biochemical marker combinations may be more sensitive than individual biochemical markers for reflecting structural damage in patients with knee OA. The differences in biochemical marker profiles associated with osteophytes compared with those associated with subchondral BMD raise the possibility that these 2 processes, commonly seen in bone in knee OA, have underlying biologic differences.

Type II collagen markers in osteoarthritis: what do they indicate?

PURPOSE OF REVIEW

We provide a critical review of recent in-vitro, animal and human clinical studies on type II collagen biomarkers. In describing the human studies, we have applied the BIPED (burden of disease, investigative, prognostic, efficacy of intervention, and diagnostic) classification scheme recently proposed by the Osteoarthritis Biomarkers Network (a consortium of five US National Institutes of Health designated sites). Based on this analysis, we propose an update to the classification of the type II collagen biomarkers.

RECENT FINDINGS

Various type II collagen epitopes have been described as potential biomarkers for osteoarthritis. Some have demonstrated ability in the following areas: classification of individuals as either diseased or nondiseased; assessment of severity or extent of osteoarthritis; prediction of future onset of osteoarthritis among those without osteoarthritis at baseline or the progression of osteoarthritis among those with existing disease; and monitoring treatment efficacy.

SUMMARY

Type II collagen biomarkers provide useful information for clinical and research applications. Furthermore, they are promising tools for the monitoring the influence of drug treatment on cartilage metabolism in joint diseases such as osteoarthritis.

Use of biochemical markers to study and follow patients with osteoarthritis

Osteoarthritis is characterized by progressive destruction of articular cartilage and subchondral bone and synovial reaction. Radiologic findings that form the basis of the diagnosis of osteoarthritis are poorly sensitive to detect early disease and for monitoring progression of joint damage. Blood-based proteomic analyses suggest that biochemical alterations can be observed well before radiologic damage is evidenced. New cartilage-specific markers, including assays for type II collagen synthesis and degradation, have been developed. Recent prospective studies indicate that blood and urine levels of these new markers are associated with progression of joint damage. Biological markers respond rapidly to treatment and therefore will certainly play an important role in the development and the monitoring of disease-modifying therapies. Because osteoarthritis involves different tissues and complex biologic processes, a combination of different biochemical markers appears to be the most promising diagnostic strategy.

Biological markers in osteoarthritis

Osteoarthritis (OA) is a progressive disorder characterized by destruction of articular cartilage and subchondral bone, and by synovial changes. The diagnosis of OA is generally based on clinical and radiographic changes, which occur fairly late during disease progression and have poor sensitivity for monitoring disease progression. Progression of joint damage is likely to result primarily from an imbalance between cartilage degradation and repair, so measuring markers of these processes would seem a promising approach to improve the prediction of disease progression at the individual level. Moreover, genetic markers might be useful predictors of prognosis. The lack of fully effective, chondroprotective medications has limited the use of such potential markers to monitor the effect of treatment for OA. Nevertheless, owing to their dynamic changes in response to treatment, biological markers might provide relevant information more rapidly than imaging techniques (such as radiography and MRI) can, and should contribute to our understanding of mechanisms that underlie the clinical efficacy of OA treatments. Most of the identified genes involved in OA encode signal-transduction proteins, which provide the potential for novel therapeutic approaches. In this Review, we will use the recently proposed BIPED (i.e. burden of disease, investigative, prognostic, efficacy of intervention and diagnostic) classification of OA markers to describe the potential usage of a given marker.

New biochemical markers of osteoarthritis

Osteoarthritis is characterized by the progressive destruction of articular cartilage and subchondral bone and synovial reaction. Radiological findings that form the basis of the diagnosis of osteoarthritis are poorly sensitive for detecting early disease and monitoring progression of joint damage. New specific and sensitive biochemical markers of cartilage and synovial tissue turnover, including assays for Type II collagen synthesis and degradation, have been developed. Recent prospective studies indicate that blood and urine levels of these new markers are associated with the progression of joint damage. Biological markers respond rapidly to treatment, and thus will certainly play an important role in the development and monitoring of disease-modifying therapies. As osteoarthritis involves different tissues and complex biological processes, a combination of different biochemical markers appears to be the most promising diagnostic strategy.

Review: Collagen markers in early arthritic diseases

In arthritic diseases e.g. osteoarthritis (OA) and rheumatoid arthritis (RA), the stability of the collagen type II (CII) fibers, a major component of articular cartilage, is compromised with extensive proteolytic breakdown leading to cartilage erosion and joint deterioration. A clinical need for molecular markers that give instantaneous measure of rate of joint deterioration has developed, as other measurements e.g. arthroscopy, and joint space narrowing are insensitive to small changes in disease status over short periods of time. Owing to its exclusive presence in cartilaginous tissues, markers of CII synthesis and degradation have been extensively studied. Assays that measure these markers in biological fluids e.g. synovial fluid (SF), serum, and urine have been developed and applied to detect early disease onset, monitor disease progression, and response to anti-arthritic drugs. CII synthesis markers include the procollagen type II C-propeptide (PIICP) and the procollagen type IIA N-propeptide (PIIANP). CII degradation markers include CII C-telopeptide (CII-X), CII neoepitope (TIINE), helix II, C2C, CNBr 9.7, Coll 2-1, and Coll 2-1 NO(2). Most of these markers differentiate between early stages of OA, RA and reference controls. The best correlations with structural changes occur when measurements are made in SF while serum measurement frequently did not correlate with structural changes. Although the selection of an optimal marker or a set of markers is still problematic, few markers are of considerable utility in early detection and monitoring of arthritic diseases. The current challenge is to improve the discriminatory power of these markers so they can be used to guide therapeutic decisions.

Long term NSAID treatment inhibits COX-2 synthesis in the knee synovial membrane of patients with osteoarthritis: differential proinflammatory cytokine profile between celecoxib and aceclofenac

OBJECTIVE

To compare the effect of celecoxib with that of a classic non-steroidal anti-inflammatory drug (NSAID) on synovial inflammation and on the synovial expression of proinflammatory genes in patients with knee osteoarthritis (OA).

METHODS

30 patients with severe knee OA scheduled for total knee replacement surgery were included in a 3 month clinical trial. They were randomised to two groups: patients treated with celecoxib (CBX) (200 mg/24 h) and patients treated with aceclofenac (ACF) (100 mg/12 h). Those patients with OA who did not want to be treated with NSAIDs served as a control group. During knee surgery, synovial fluid (SF) and synovial membrane (SM) were collected. A SM specimen was fixed and embedded in paraffin and another part was frozen for molecular biology studies.

RESULTS

At the end of study both CBX and ACF treated patients showed a significant improvement in pain and knee function compared with controls. Both drugs significantly reduced prostaglandin E(2) (PGE(2)) SF concentration and down regulated COX-2 mRNA and protein expression at the SM. However, synovial macrophage infiltration (CD68 antigen staining) and expression of proinflammatory mediators, such as interleukin 1beta and tumour necrosis factor alpha, were decreased only by CBX treatment.

CONCLUSION

Both drugs improved joint pain and function, inhibited SF PGE(2) concentration, and induced a decrease in synovial COX-2 expression and synthesis not related to the tissue inflammatory status. These data suggest that PGE(2) blocking agents may decrease PGE(2) production not only by direct COX-2 inhibition but also by down regulating COX-2 expression and synthesis. However, CBX and ACF appear to have different anti-inflammatory profiles in controlling OA synovial macrophage infiltration and proinflammatory expression.

Biomarkers in osteoarthritis

PURPOSE OF REVIEW

Biomarker discovery and validation for osteoarthritis have accelerated over the past several years, coincident with an evolving understanding of joint tissue molecules and their complex interactions, and the compelling need for improved osteoarthritis outcome measures in clinical trials. This review highlights advances in osteoarthritis-related biomarker research within the past year.

RECENT FINDINGS

The studies in the past year involving biochemical markers in humans can be assigned to one of four categories: new approaches and new biomarkers, exploratory studies in specialized disease subsets, large cross-sectional validation studies, and longitudinal studies, with and without an intervention.

SUMMARY

Most these studies have examined the association of a biomarker with some aspect of the natural history of osteoarthritis. As illustrated by the six studies reviewed here that included therapeutic interventions, however, several biomarkers are emerging that display credible association with disease modification. The expanding pool of informative osteoarthritis-related biomarkers is expected to positively impact the development of therapeutics for this disease and, it is hoped, ultimately clinical care.

In Vitro, Ex Vivo, andIn VivoMethodological Approaches for Studying Therapeutic Targets of Osteoporosis and Degenerative Joint Diseases: How Biomarkers Can Assist?

Although our approach to the clinical management of osteoporosis (OP) and degenerative joint diseases (DJD)-major causes of disability and morbidity in the elderly-has greatly advanced in the past decades, curative treatments that could bring ultimate solutions have yet to be found or developed. Effective and timely development of candidate drugs is a critical function of the availability of sensitive and accurate methodological arsenal enabling the recognition and quantification of pharmacodynamic effects. The established concept that both OP and DJD arise from an imbalance in processes of tissue formation and degradation draws attention to need of establishing in vitro, ex vivo, and in vivo experimental settings, which allow obtaining insights into the mechanisms driving increased bone and cartilage degradation at cellular, organ, and organism levels. When addressing changes in bone or cartilage turnover at the organ or organism level, monitoring tools adequately reflecting the outcome of tissue homeostasis become particularly critical. In this context, bioassays targeting the quantification of various degradation and formation products of bone and cartilage matrix elements represent a useful approach. In this review, a comprehensive overview of widely used and recently established in vitro, ex vivo, and in vivo set-ups is provided, which in many cases effectively take advantage of the potentials of biomarkers. In addition to describing and discussing the advantages and limitations of each assay and their methods of evaluation, we added experimental and clinical data illustrating the utility of biomarkers for these methodological approaches.

Comparative Effect of Nimesulide and??Ibuprofen on the Urinary Levels of??Collagen Type II C-Telopeptide Degradation Products and on the Serum Levels of Hyaluronan and Matrix Metalloproteinases-3 and -13 in??Patients with Flare-Up of Osteoarthritis

BACKGROUND AND AIM

Because in vitro studies have shown that nimesulide not only preferentially inhibits COX-2 but also reduces the action/release of pro-inflammatory cytokines, down-regulates the synthesis and/or activity of collagenase(s), and releases reactive oxygen species and other toxic substances from neutrophils, this study investigated whether nimesulide and ibuprofen could affect levels of biochemical markers of joint inflammation and collagen catabolism in patients with flare-up of knee or hip osteoarthritis.

METHODS

Ninety patients were included in this randomised, prospective, single- blind study. They received either nimesulide (n = 45) or ibuprofen (n = 45) for a 4-week treatment period. The following parameters were analysed by ELISA: urinary levels of C-terminal cross-linking telopeptide of type II collagen (CTX-II), a marker of type II collagen breakdown; serum levels of hyaluronan (HA), a marker of synovial inflammation and hyperplasia; and circulating levels of stromelysin-1 (matrix metalloproteinase-3 [MMP-3]), collagenase-1 (MMP-1) and collagenase-3 (MMP-13). Statistical analysis used was ANOVA.

RESULTS

At the end of the treatment period, nimesulide but not ibuprofen markedly reduced the urinary levels of CTX-II (p < 0.001) and the serum levels of HA (p < 0.05), two markers known to prognosticate poor outcome of the osteoarthritis disease process. Nimesulide also reduced the serum levels of both MMP-3 (p < 0.05) and MMP-13 (p < 0.001). Furthermore, in the nimesulide group, the decrease in levels of CTX-II correlated significantly with the decrease in levels of HA and MMP-13.

CONCLUSION

Although nonsteroidal anti-inflammatory drugs are effective in improving pain and disability in OA patients, to date it has been unclear to what extent these drugs could affect joint metabolism and hence joint structure. Patients with flare-up of their osteoarthritis disease process exhibit enhanced levels of markers of joint inflammation and cartilage collagen breakdown, which were markedly decreased by nimesulide but not by ibuprofen.