Increased concentrations of proteoglycan components in the synovial fluids of patients with acute but not chronic joint disease

Relationship between T1rho magnetic resonance imaging, synovial fluid biomarkers, and the biochemical and biomechanical properties of cartilage

Non-invasive techniques for quantifying early biochemical and biomechanical changes in articular cartilage may provide a means of more precisely assessing osteoarthritis (OA) progression. The goals of this study were to determine the relationship between T1rho magnetic resonance (MR) imaging relaxation times and changes in cartilage composition, cartilage mechanical properties, and synovial fluid biomarker levels and to demonstrate the application of T1rho imaging to evaluate cartilage composition in human subjects in vivo. Femoral condyles and synovial fluid were harvested from healthy and OA porcine knee joints. Sagittal T1rho relaxation MR images of the condyles were acquired. OA regions of OA joints exhibited an increase in T1rho relaxation times as compared to non-OA regions. Furthermore in these regions, cartilage sGAG content and aggregate modulus decreased, while percent degraded collagen and water content increased. In OA joints, synovial fluid concentrations of sGAG decreased and C2C concentrations increased compared to healthy joints. T1rho relaxation times were negatively correlated with cartilage and synovial fluid sGAG concentrations and aggregate modulus and positively correlated with water content and permeability. Additionally, we demonstrated the application of these in vitro findings to the study of human subjects. Specifically, we demonstrated that walking results in decreased T1rho relaxation times, consistent with water exudation and an increase in proteoglycan concentration with in vivo loading. Together, these findings demonstrate that cartilage MR imaging and synovial fluid biomarkers provide powerful non-invasive tools for characterizing changes in the biochemical and biomechanical environments of the joint.

Inflammatory cytokines and biomarkers of cartilage metabolism 8 years after anterior cruciate ligament reconstruction: results from operated and contralateral knees

BACKGROUND

Patients who sustain an acute anterior cruciate ligament (ACL) rupture are at increased risk to develop posttraumatic arthritis (PTA) in the injured knee whether the ACL is reconstructed or treated nonoperatively. Inflammatory cytokines and cartilage degradation biomarkers are elevated at the time of acute injury and postoperatively. This suggests that one mechanism for PTA may be an inflammatory degradative process initiated on the acute injury and sustained for some length of time independent of whether adequate joint stability is restored.

HYPOTHESIS

Inflammatory cytokines and biomarkers of cartilage degradation are elevated in the synovial fluid several years after reconstruction of the ACL, indicating an ongoing imbalance between extracellular matrix destruction and repair.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

In 11 patients who had undergone ACL reconstruction 8 years earlier, knee synovial fluid was aspirated from the operated knee and the contralateral nonoperated knee. The synovial fluid was analyzed for interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, sulfated glycosaminoglycans (sGAG), aggrecan neoepitope fragment (ARGS-aggrecan), and cartilage oligomeric matrix protein (COMP). At follow-up, the patients underwent bilateral weightbearing radiographs and bilateral MRIs of their knees.

RESULTS

No significant differences between the operated and the contralateral knee were found for the synovial fluid concentrations of IL-1β, IL-6, TNF-α, sGAG, ARGS-aggrecan, or COMP. There were significantly more radiographically visible osteoarthritic changes in the operated knees compared with the contralateral knees. MRIs revealed that all grafts and all contralateral ACLs were intact and, furthermore, that there was significantly more meniscal and cartilage damage in the index knees than the contralateral knees.

CONCLUSION

Eight years after ACL reconstruction, there were no significant differences in inflammatory cytokines and biomarkers for cartilage degeneration between the nonoperated and the ACL-reconstructed knee, even though there were more osteoarthritic changes and meniscal and cartilage damage in the operated knee, as seen on weightbearing radiographs and MRI.

Di-sulfated Keratan Sulfate as a Novel Biomarker for Mucopolysaccharidosis II, IVA, and IVB

Keratan sulfate (KS) is a storage material in mucopolysaccharidosis IV (MPS IV). However, no detailed analysis has been reported on subclasses of KS: mono-sulfated KS and di-sulfated KS. We established a novel method to distinguish and quantify mono- and di-sulfated KS using liquid chromatography-tandem mass spectrometry and measured both KS levels in various specimens.Di-sulfated KS was dominant in shark cartilage and rat serum, while mono-sulfated KS was dominant in bovine cornea and human serum. Levels of both mono- and di-sulfated KS varied with age in the blood and urine from control subjects and patients with MPS II and IVA. The mean levels of both forms of KS in the plasma/serum from patients with MPS II, IVA, and IVB were elevated compared with that in age-matched controls. Di-sulfated KS provided more significant difference between MPS IVA and the age-matched controls than mono-sulfated KS. The ratio of di-sulfated KS to total KS in plasma/serum increased with age in control subjects and patients with MPS II but was age independent in MPS IVA patients. Consequently, this ratio can discriminate younger MPS IVA patients from controls. Levels of mono- and di-sulfated KS in urine of MPS IVA and IVB patients were all higher than age-matched controls for all ages studied.In conclusion, the level of di-sulfated KS and its ratio to total KS can distinguish control subjects from patients with MPS II, IVA, and IVB, indicating that di-sulfated KS may be a novel biomarker for these disorders.

Establishment of glycosaminoglycan assays for mucopolysaccharidoses

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by deficiency of the lysosomal enzymes essential for catabolism of glycosaminoglycans (GAGs). Accumulation of undegraded GAGs results in dysfunction of multiple organs, resulting in distinct clinical manifestations. A range of methods have been developed to measure specific GAGs in various human samples to investigate diagnosis, prognosis, pathogenesis, GAG interaction with other molecules, and monitoring therapeutic efficacy. We established ELISA, liquid chromatography tandem mass spectrometry (LC-MS/MS), and an automated high-throughput mass spectrometry (HT-MS/MS) system (RapidFire) to identify epitopes (ELISA) or disaccharides (MS/MS) derived from different GAGs (dermatan sulfate, heparan sulfate, keratan sulfate, and/or chondroitin sulfate). These methods have a high sensitivity and specificity in GAG analysis, applicable to the analysis of blood, urine, tissues, and cells. ELISA is feasible, sensitive, and reproducible with the standard equipment. HT-MS/MS yields higher throughput than conventional LC-MS/MS-based methods while the HT-MS/MS system does not have a chromatographic step and cannot distinguish GAGs with identical molecular weights, leading to a limitation of measurements for some specific GAGs. Here we review the advantages and disadvantages of these methods for measuring GAG levels in biological specimens. We also describe an unexpected secondary elevation of keratan sulfate in patients with MPS that is an indirect consequence of disruption of catabolism of other GAGs.

Alterations of plasma glycosaminoglycan profile in patients with rheumatoid arthritis in relation to disease activity

BACKGROUND

Qualitative and quantitative evaluation of plasma glycosaminoglycans (GAGs) of rheumatoid arthritis (RA) patients in relation to disease activity estimated by DAS28 score was evaluated.

METHODS

GAGs were quantified by hexuronic acid assay and electrophoretic fractionation. Keratan sulfate (KS) and hyaluronic acid (HA) were measured by immunoassay.

RESULTS

Chondroitin/dermatan sulfate (CS/DS) and heparan sulfate/heparin (HS/H) in plasma of healthy subjects and RA patients were stated. Total GAGs, CS, HS/H and HA levels were higher in patients with high and moderate disease activity than in controls. Total GAGs and CS levels in patients with high disease activity were elevated in comparison to patients with low disease activity. HS/H levels in patients with high and moderate activity were elevated in comparison to those with low disease activity. KS levels were increased in all patient groups in comparison to controls. Total GAGs, CS, HS/H and HA levels were positively correlated with DAS28 and CRP.

CONCLUSIONS

Structural tissue damage/remodeling of the extracellular matrix occurs in RA, which is reflected in the qualitative and quantitative changes of plasma GAGs. The above changes depend on DAS28 and may contribute to systemic changes in the properties of the extracellular matrix.

Newborn screening and diagnosis of mucopolysaccharidoses: application of tandem mass spectrometry

Mucopolysaccharidoses (MPS) are a group of lysosomal storage disorders caused by the deficiency of lysosomal enzymes. The enzymes are required to break down glycosaminoglycans (GAGs) that help build bone, cartilage, tendons, corneas, skin and connective tissue. In patients with MPS, a missing enzyme leads to the accumulation of GAGs in the cells, blood, connective tissues, and multiple organs. The consequence is permanent, with progressive cellular damage affecting patients' appearance, physical abilities, organ and system function, and skeletal and mental development. The measurement of each specific GAG in a variety of specimens is required to establish the correlation between GAGs and physiological status of patients and/or prognosis and pathogenesis of the disease and to separate the patients with MPS from the healthy controls. We have developed a highly accurate, sensitive, and cost-effective liquid chromatography tandem mass spectrometry (LC-MS/MS) method for measurements of disaccharides derived from four specific GAGs [chondroitin sulfate (CS), dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS)]. Disaccharides were produced by specific enzyme digestion of each GAG, and subsequently, quantified by negative ion mode of multiple reaction monitoring. Subclasses of GAGs with the same molecular weights can be separated by liquid chromatography. We have also developed another GAG assay by high-throughput mass spectrometry (HT-MS/MS). The HT-MS/MS consists of an integrated solid phase extraction robot that binds and de-salts samples from assay plates and directly injects them into a MS/MS detector, reducing sample processing time to within ten seconds. HT-MS/MS consequently yields much faster throughput than conventional LC-MS/MS-based methods; however, the HT-MS/MS system does not use a chromatographic step, and therefore, cannot separate GAGs that have the same molecular weights. Both techniques can be applied to the analysis of dried blood spots, blood, and urine specimens. In this review, we describe the assay methods for GAGs and the application to newborn screening and diagnosis of MPS.

Comparisons of the chondroitin sulphate levels in orthodontically moved canines and the clinical outcomes between two different force magnitudes

The aims of this study were to compare the chondroitin sulphate (CS) levels in gingival crevicular fluid (GCF) of moved canines using either 70 or 120 g of orthodontic force, and to compare the rate of tooth movement and the amount of pain between these two force magnitudes. Sixteen patients (6 males and 10 females; aged 16.91 ± 2.99 years), with class I malocclusion, who required orthodontic treatment with first premolar extractions, were recruited. The force magnitudes used to move the maxillary canines distally were controlled at 70 and 120 g on the right and the left sides, respectively. GCF samples were collected with Periopaper(®) strips before and during orthodontic tooth movement. Competitive ELISA with monoclonal antibody was used to measure the CS levels. The distance of tooth movement and the amount of pain assessed by visual analog scale (VAS) scores were evaluated. The medians of CS levels during the loaded period were significantly greater than those during the unloaded period (P < 0.05). The differences between the medians of CS levels of 70 g and 120 g retraction force during each 1 week period were not significant. There was no significant difference in the rates of canine movement between these two force magnitudes. However, using 120 g, the medians of VAS scores were significantly greater than those with 70 g (P < 0.05). Collectively, 70 g retraction force appears to be sufficient and more suitable than 120 g force as it causes no difference in biochemically-assessed bone remodelling activity, the same rate of tooth movement, reduced pain and better comfort.

Measurement of glycosaminoglycans in canine synovial fluid and its correlation with the cause of secondary osteoarthritis, age and body weight

Glycosaminoglycans are natural components of healthy joint cartilage and they also appear in healthy synovial fluid. An increased amount of glycosaminoglycans in synovial fluid is believed to be a marker of secondary osteoarthritis, regardless of its primary cause. The aim of our study was to define the relationship between glycosaminoglycans in the synovial fluid and joint disorders, age, and body weight. The samples of synovial fluid were obtained from dogs suffering from secondary secondary osteoarthritis (n = 35) and from control dogs (n = 18); control dogs had normal body weight. The results were compared among joints of dogs with secondary osteoarthritis divided into groups according to the criteria mentioned above and control dogs. Glycosaminoglycan concentrations in synovial fluid were measured using dimethylmethylene blue assay. The lowest mean value of glycosaminoglycans in synovial fluid was measured in the control group. Significantly higher glycosaminoglycan content (P < 0.05) was found in synovial fluid isolated from obese dogs compared to control dogs. Furthermore, we observed an age-related trend, in which the highest mean values were reached either in old dogs or pups. Despite the absence of significant differences in glycosaminoglycan values among dogs suffering from various types of secondary secondary osteoarthritis, the highest mean values were measured in fragmented coronoid processus group. Our data suggest that abnormally increased body weight has an impact on glycosaminoglycan concentration in synovial fluid which may imply faster degradation and turnover of joint cartilage. Such observation has not yet been published in veterinary medicine.

Evidence for lysosomal exocytosis and release of aggrecan-degrading hydrolases from hypertrophic chondrocytes, in vitro and in vivo

The abundant proteoglycan, aggrecan, is resorbed from growth plate cartilage during endochondral bone ossification, yet mice with genetically-ablated aggrecan-degrading activity have no defects in bone formation. To account for this apparent anomaly, we propose that lysosomal hydrolases degrade extracellular, hyaluronan-bound aggrecan aggregates in growth plate cartilage, and that lysosomal hydrolases are released from hypertrophic chondrocytes into growth plate cartilage via Ca²⁺-dependent lysosomal exocytosis. In this study we confirm that hypertrophic chondrocytes release hydrolases via lysosomal exocytosis in vitro and we show in vivo evidence for lysosomal exocytosis in hypertrophic chondrocytes during skeletal development. We show that lysosome-associated membrane protein 1 (LAMP1) is detected at the cell surface following in vitro treatment of epiphyseal chondrocytes with the calcium ionophore, ionomycin. Furthermore, we show that in addition to the lysosomal exocytosis markers, cathepsin D and β-hexosaminidase, ionomycin induces release of aggrecan- and hyaluronan-degrading activity from cultured epiphyseal chondrocytes. We identify VAMP-8 and VAMP7 as v-SNARE proteins with potential roles in lysosomal exocytosis in hypertrophic chondrocytes, based on their colocalisation with LAMP1 at the cell surface in secondary ossification centers in mouse tibiae. We propose that resorbing growth plate cartilage involves release of destructive hydrolases from hypertrophic chondrocytes, via lysosomal exocytosis.

Investigating ADAMTS-mediated aggrecanolysis in mouse cartilage

Proteolysis of the cartilage proteoglycan aggrecan is a feature of arthritis. We present a method for analyzing aggrecanolysis in in vitro cultures of 3-week-old mouse femoral head cartilage based on traditional methods developed for large animal species. Investigators can choose either a simple analysis that detects several aggrecan fragments released into culture medium only or a more comprehensive study that detects all fragments present in both the medium and the cartilage matrix. The protocol comprises (i) cartilage culture and optional cartilage extraction, (ii) a quick and simple colorimetric assay for quantitating aggrecan and (iii) neoepitope western blotting to identify specific aggrecan fragments partitioning to the medium or cartilage compartments. The crucial difference between the methods for mice and larger animals is that the proportion of aggrecan in a given sample is normalized to total aggrecan rather than to tissue wet weight. This necessary break from tradition arises because tiny volumes of liquid clinging to mouse cartilage can increase the apparent tissue wet weight, causing unacceptable errors. The protocol has broad application for the in vitro analysis of transgenic mice, particularly those with mutations that affect cartilage remodeling, arthritic disease and skeletal development. The protocol is robust, reliable and takes 7-11 d to complete.

In vitro expansion and differentiation of fresh and revitalized adult canine bone marrow-derived and adipose tissue-derived stromal cells

The objective of this study was to determine the tissue density, in vitro expansion and differentiation of canine adipose tissue-derived (ASC) and bone marrow-derived (BMSC) stromal cells. Primary (P0) and cell passages 1-6 (P1-6) cell doubling numbers (CD) and doubling times (DT) were determined in fresh cells. The P0, P3, and P6 adipogenic (CFU-Ad), osteogenic (CFU-Ob), and fibroblastic (CFU-F) colony forming unit frequencies, lineage specific mRNA levels in differentiated P3 cells and composition of P3 and P6 chondrogenic pellets were assessed in cryogenically preserved cells. Cell yields from bone marrow were significantly higher than adipose tissue. Overall ASC and BMSC CDs and DTs and P3 and P6 CFU-F, CFU-Ad, and CFU-Ob were comparable. The P0 BMSC CFU-Ob was significantly higher than ASC. Lineage specific mRNA levels were higher in differentiated versus control cells, but similar between cell types. Protein was significantly greater in P3 versus P6 ASC chondrogenic pellets. Based on these findings, fresh and revitalized canine ASCs are viable alternatives to BMSCs for stromal cell applications.

In vitro adult canine adipose tissue-derived stromal cell growth characteristics

Stromal cells are undifferentiated cells found in embryonic and adult tissues. Adult mesenchymal stromal cells (MSCs) possess the properties of self renewal, long-term viability, multipotentiality, and immune privilege, which make them attractive candidates for regenerative medicine applications. In order to develop targeted adult stromal cell therapies for diseased and injured tissues in animals and humans, it is essential to have large-animal models. The dog represents not only a patient population, but is also a valuable experimental model. The dog has contributed significantly to the understanding of various human diseases such as genetic and musculoskeletal disorders. In order to optimize the use of stromal cell therapy in the dog as a patient or disease model, a comprehensive characterization of the cells is required.

Growth factor-rich plasma increases tendon cell proliferation and matrix synthesis on a synthetic scaffold: an in vitro study

Numerous scaffolds have been proposed for use in connective tissue engineering. Although these scaffolds direct cell migration and attachment, many are biologically inert and thus lack the physiological stimulus to attract cells and induce mitogenesis and matrix synthesis. In the current study, a bioactive scaffold was created by combining a synthetic scaffold with growth factor-rich plasma (GFRP), an autologous concentration of growth factors derived from a platelet-rich plasma preparation. In vitro tendon cell proliferation and matrix synthesis on autologous GFRP-enriched scaffolds, autologous serum-enriched scaffolds, and scaffolds alone were compared. The GFRP preparation was found to have a 4.7-fold greater concentration of a sentinel growth factor (transforming growth factor-beta1) compared with serum. When combined with media containing calcium, the GFRP produced a thin fibrin matrix over and within the GFRP-enriched scaffolds. Cell proliferation assays demonstrated that GFRP-enriched scaffolds significantly enhanced cell proliferation over autologous serum and control groups at both 48 and 72 h. Analysis of the scaffolds at 14, 21, and 28 days revealed that GFRP-enriched scaffolds significantly increased the deposition of a collagen-rich extracellular matrix when compared with the other groups. These results indicate that GFRP can be used to enhance in vitro cellular population and matrix deposition of tissue-engineered scaffolds.

Relationship between synovial fluid levels of glycosaminoglycans, hydroxyproline and general MMP activity and the presence and severity of articular cartilage change on the proximal articular surface of P1

REASONS FOR PERFORMING STUDY

Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting horses and leads to degeneration of articular cartilage. Diagnosis is based on clinical signs in combination with radiography, which is relatively insensitive and provides only an indication of accumulated damage. Alternative methods, such as molecular markers, are therefore needed that can quantitatively, reliably and sensitively detect osteoarthritic changes in the joints at an early stage of the disease. If such markers are to be used reliably, it is important to know the relationship between marker concentration and cartilage composition.

OBJECTIVES

To study the relationship between cartilage composition, synovial fluid levels of glycosaminoglycans (GAGs), hydroxyproline (Hyp) and general matrix metalloproteinase (MMP) activity, and the presence and severity of articular cartilage damage on the articular surface of P1.

METHODS

Synovial fluid (SF) was collected from the metacarpophalangeal joints of 60 mature horses, and levels of GAGs, Hyp and general MMP activity were determined. Further, GAG and denatured collagen content of the articular cartilage were determined at the dorsal articular margin of P1 (site 1) and central cavity (site 2). The presence and severity of cartilage change was quantified using the cartilage degeneration index (CDI), measured at the same 2 sites. Correlations between SF parameters, cartilage composition and degree of cartilage degeneration were sought using correlation analysis.

RESULTS

There was no correlation between GAG or Hyp content of SF and the amount of GAGs or denatured collagen, respectively, in cartilage. In joints with moderate to severe cartilage damage, the GAG content of site 1 was significantly lower than in joints with no to minimal cartilage change (P = 0.005) and there was a negative correlation between the amount of denatured collagen and GAG content at site 1 in all joints (r = -039, P = 0.002). Further, in joints with moderate to severe cartilage damage, there was a significant positive correlation between MMP activity in SF and Hyp levels in SF (r = 0.72, P < 0.001) and CDI at sites 1 (r = 0.46, P = 0.03) and 2 (r = 0.43, P = 0.04).

CONCLUSIONS

General MMP activity in joints with moderate to severe cartilage damage is related to the severity of those cartilage changes and to Hyp levels in SF. Glycosaminoglycan levels in SF are not directly related to MMP activity, GAG content of articular cartilage or severity of cartilage change.

POTENTIAL RELEVANCE

Glycosaminoglycan levels in SF are not helpful for the early detection of cartilage lesions. In damaged joints, Hyp levels may give an indication of the severity of cartilage change as they are strongly related to MMP activity, but do not qualify as markers for the presence or absence of cartilage lesions.

Chondroitin sulphate (WF6 epitope) levels in peri-miniscrew implant crevicular fluid during orthodontic loading

The aim of this study was to monitor changes in chondroitin sulphate (CS; WF6 epitope) levels in peri-miniscrew implant crevicular fluid (PMICF) during orthodontic loading. Ten patients (seven males and three females; aged 22.0 +/- 3.4 years), who required orthodontic treatment with extraction of all four premolar teeth, participated in the study. Twenty miniscrew implants (used as orthodontic anchorage) were placed, two in each patient, buccally and bilaterally in the alveolar bone between the roots of the maxillary posterior teeth. Sentalloy closed-coil springs (50 g) were used to load the miniscrew implants and to move the maxillary canines distally. During the unloaded period, PMICF samples were collected on days 1, 3, 5, and 7 after miniscrew implant placement and on days 14, 21, 28, and 35 during the loaded period. Clinical mobility assessments of the miniscrew implants were recorded at each visit. The competitive enzyme-linked immunosorbent assay with monoclonal antibody WF6 was used to detect CS (WF6 epitope) levels in the PMICF samples. The differences between the CS (WF6 epitope) levels during the unloaded and loaded periods were determined by a Mann-Whitney U-test. During the loaded period, two miniscrew implants were considered to have failed. The CS (WF6 epitope) levels during the unloaded period ranged from 0.00 to 758.03 ng/ml and those during the loaded period from 0.00 to 1025.11 ng/ml. Medians of CS (WF6 epitope) levels, around 'immobile' miniscrew implants, between the unloaded and loaded periods were not significantly different (P = 0.07). CS (WF6 epitope) levels in PMICF can be detected and may be used as biomarkers for assessing alveolar bone remodelling around miniscrew implants during orthodontic loading.

The effects of early or late treatment of osteochondral defects on joint homoeostasis: an experimental study in rabbits

A 3.5 x 4 mm tubular osteochondral defect was created on the right medial femoral condyles of 51 adult rabbits. In the control group (CG), defects were left untreated. In the early-(ETG) and late-(LTG) treatment groups, defects were treated by an osteoperiosteal graft 1 and 12 weeks, respectively, after the index procedure. Synovial fluid (SF) samples were collected regularly and proteoglycan fragments (PF), total collagen (TC) and collagenase (MMP-1) levels were measured. Rabbits were killed at 4 (early period), 12 (intermediate period), or 24 (late period) weeks postoperatively. Histological examination indicated a more successful healing in both grafting groups than in the CG, but without any difference at any time period between the grafting groups. In the CG, PF, and TC levels in SF increased continuously until the late period, indicating an ongoing degenerative activity in the joints. In contrast, SF marker levels in both grafting groups indicated that normalization in joint metabolism could be achieved-at least partially-after treatment. However, PF levels in the SF showed that the treatment of defects in earlier stages might result in better outcomes since the negative effects were more prominent in chronic stages, presumably due to the more prolonged period of disturbed homeostasis. Thus, histological values and SF marker levels indicated that treatment of osteochondral defects at any time of the disease had a positive effect on healing when compared to no treatment. Early treatment might better assist the recovery of joint homeostasis than late treatment.

Changes in synovial fluid and serum biomarkers with exercise and early osteoarthritis in horses

OBJECTIVE

To discriminate between changes in biomarkers with exercise compared to changes in biomarkers with osteoarthritis (OA) in exercising horses.

METHOD

Sixteen, 2-year-old horses were randomly assigned either to an exercise-alone (n=8) or OA-affected (also exercised) (n=8) group. All horses had both mid-carpal joints arthroscoped and OA induced in one mid-carpal joint in the OA-affected joints of OA-affected horses. Two weeks after surgery all horses commenced a strenuous exercise program on a high-speed treadmill. Clinical outcomes and synovial fluid and serum biomarkers, were evaluated weekly. Synovial and serum biomarkers evaluated were epitope CS846 (CS846), epitope CPII (CPII), glycosaminoglycans (GAGs), epitope Col CEQ (Col CEQ) (a marker of type II collagen degradation), type I and II collagen degradation fragments (C1,2C), osteocalcin, C-terminal of bone type I collagen (CTX1), type I collagen (Col I) and (synovial fluid only of cartilage) prostaglandin E2 (PGE2) levels. Horses were euthanized at day 91 and their joints assessed grossly, histopathologically, and histochemically.

RESULTS

Exercise induced a significant increase in synovial fluid CS846, CPII, GAG, Col CEQ, C1,2C, osteocalcin and Col I concentrations. There was a significant increase in synovial fluid CS846, CPII, Col CEQ, C1,2C, osteocalcin, Col I and PGE2 concentrations in OA-affected joints compared to exercise-alone joints. The concentration of serum CS846, CPII, GAG, osteocalcin, C1,2C and Col I increased with exercise. For each of these biomarkers there was also a statistically significant increase in serum biomarker levels in OA-affected horses compared to exercise-alone horses.

CONCLUSIONS

Six synovial fluid and serum biomarkers were useful in separating early experimental OA from exercise alone but synovial fluid CTX1 and serum Col CEQ and CTX1 were not.

Raised chondroitin sulphate WF6 epitope levels in gingival crevicular fluid in chronic periodontitis

AIM

To determine the levels of chondroitin sulphate (CS) WF6 epitope, recognized by WF6 monoclonal antibody, in gingival crevicular fluid (GCF) from different stages of periodontal disease and healthy periodontium, and to correlate those levels with clinical parameters.

MATERIAL AND METHODS

GCF samples, collected from 389 sites, were analysed for the WF6 epitope levels by the competitive enzyme-linked immunosorbent assay.

RESULTS

The median WF6 epitope level was significantly higher in chronic periodontitis sites (n=185) than in healthy and gingivitis sites (n=204) (p<0.001), whereas the median levels did not significantly differ between healthy (n=65) and gingivitis sites (n=139). The median level in severe periodontitis sites (n=60) was significantly higher than that in moderate periodontitis sites (n=63) (p=0.019). Similarly, the median level in moderate periodontitis sites was significantly higher than that in slight periodontitis sites (n=62) (p=0.001). The WF6 epitope levels significantly correlated with probing depth (r=0.777, p=0.001) and loss of clinical attachment level (r=0.814, p=0.001).

CONCLUSION

Elevated CS WF6 epitope levels in GCF are associated with severity of periodontitis. The WF6 antibody may therefore be clinically applied to monitor disease severity and progression.

Effect of COX-2 inhibitors and non-steroidal anti-inflammatory drugs on a mouse fracture model

A randomised, blinded, prospective animal study with 296 male C57BL/6N mice was performed to evaluate the biomechanical, biomolecular, biochemical, and histological impact of anti-inflammatory medications on fracture healing. A reproducible closed tibia fracture was created and stabilised with an intramedullary pin. Animals were randomised to placebo, ketorolac, ibuprofen, celecoxib, or rofecoxib treatment groups with biomechanical and biochemical testing at 4, 8, and 12 weeks. A second arm of the study was conducted in which animals were randomised to indomethacin or placebo treatment with biomechanical testing at 12 weeks. Histological and biomolecular studies were performed at 2 weeks on all groups in the first arm of the study. Biomechanical testing consisted of three-point bending evaluating maximum load, energy absorbed to maximum load, and stiffness. Safranin O-Fast Green stain was performed for histology. Biochemical quantifications of chondroitin and dermatan sulphate, hydroxyproline, total protein, and DNA content were performed. Osteocalcin and collagen types II and X were evaluated by in situ hybridisation. Some mechanical differences were seen between ketorolac and placebo at 4 weeks with respect to energy absorbed, but there were no differences in maximum load or stiffness seen between any treatment group and placebo at any time point. Indomethacin, celecoxib, rofecoxib, ibuprofen, and ketorolac did not significantly affect fracture healing in this young murine model.

The matrix-forming phenotype of cultured human meniscus cells is enhanced after culture with fibroblast growth factor 2 and is further stimulated by hypoxia

Human meniscus cells have a predominantly fibrogenic pattern of gene expression, but like chondrocytes they proliferate in monolayer culture and lose the expression of type II collagen. We have investigated the potential of human meniscus cells, which were expanded with or without fibroblast growth factor 2 (FGF2), to produce matrix in three-dimensional cell aggregate cultures with a chondrogenic medium at low (5%) and normal (20%) oxygen tension. The presence of FGF2 during the expansion of meniscus cells enhanced the re-expression of type II collagen 200-fold in subsequent three-dimensional cell aggregate cultures. This was increased further (400-fold) by culture in 5% oxygen. Cell aggregates of FGF2-expanded meniscus cells accumulated more proteoglycan (total glycosaminoglycan) over 14 days and deposited a collagen II-rich matrix. The gene expression of matrix-associated proteoglycans (biglycan and fibromodulin) was also increased by FGF2 and hypoxia. Meniscus cells after expansion in monolayer can therefore respond to chondrogenic signals, and this is enhanced by FGF2 during expansion and low oxygen tension during aggregate cultures.

Analysis of proteoglycans derived sulphated disaccharides by liquid chromatography/mass spectrometry

A method has been developed for the identification and quantitative determination of sulphated disaccharides derived from chondroitin sulphate (CS) and dermatan sulphate (DS) chains attached to proteoglycans (PGs). After digestion with Chondroitinase ABC, the pool of disaccharides can be directly separated by liquid chromatography on a porous graphitized carbon (PGC) column and identified by on-line electrospray mass spectrometry under negative ionization conditions. The relative intensities of the fragment ions obtained by MS/MS allow to distinguish the sulphate position. Calibration with standard disaccharides allows the quantification of the different isomers. The method showed good repeatability in terms of relative standard deviation (RSD < 2%) and linearity between 0.5 and 50 ng (total injected amount) for both 4- and 6-sulphated disaccharides. The limit of detection achieved in full scan mode was 0.1 ng. The methodology was applied to different types of biological samples obtained from patients suffering from chronic lung inflammation such as: lung tissue, bronchoalveolar lavage fluid (BALF), induced sputum and urine.

Retroviral transduction with SOX9 enhances re-expression of the chondrocyte phenotype in passaged osteoarthritic human articular chondrocytes

OBJECTIVES

Articular chondrocytes proliferate in monolayer culture, but the expression of the transcription factor SOX9 falls and the ability of the cells to reform cartilage tissue declines. We have investigated whether retroviral SOX9 expression in extensively passaged human articular chondrocytes from osteoarthritic (OA) joints enables the cells to regain a cartilage matrix forming phenotype in pellet culture.

DESIGN

Chondrocytes from normal and OA joints were retrovirally transduced with SOX9 and grown to passages 7-10 before being cultured as pellets of 500,000 cells for 14 days. Pellets were analysed by real time polymerase chain reaction, histology, immunohistochemistry and 1,9-dimethylmethylene blue assay.

RESULTS

Chondrocytes from OA joints displayed higher expression of COL2A1 gene when transduced with SOX9 and cultured as pellets with 10% serum, but glycosaminoglycan (GAG) synthesis was low. Addition of transforming growth factor beta-3 and insulin like growth factor-1 increased collagen II expression and GAG synthesis in these SOX9 transduced cell pellets. The cells adopted a rounded morphology and there was increased deposition of collagen II protein compared to control green fluorescent protein transduced cell pellets. Similar results were seen with transduced chondrocytes from OA or healthy cartilage. SOX9 transduced human dermal fibroblasts did not show any chondrogenic response.

DISCUSSION

Transduction with SOX9 primed the passaged articular chondrocytes to regain a chondrocytic phenotype in pellet culture and to form a cartilaginous matrix, which was enhanced by growth factors. Following transduction, chondrocytes from OA joints showed a similar capacity for chondrogenic recovery as those from healthy joints, which suggested that OA does not permanently compromise the chondrocyte phenotype.

Effect of matrix depleting agents on the expression of chondrocyte metabolism by equine chondrocytes

This study was carried out to investigate the effect of two enzymes (collagenase and chondroitinase) and two cytokines/metabolites (interleukin-1beta and retinoic acid) of known catabolic activity on the expression of cartilage metabolism/phenotype in equine articular cartilage. Articular cartilage explants from 11 horses (5-13 years old) were treated for 48 h and assayed for total sulphated glycosaminoglycan (GAG), the incorporation of 35S-sulphate, collagen degradation and mRNA expression of the proteoglycans collagen II, collagen IIA, collagen III, collagen IX, collagen X, collagen XI and glyceraldehyde-3-phosphate (GAPDH). Purified collagenase and retinoic acid were responsible for increased GAG loss from the tissues. Chondroitinase, responsible for catalysing the elimination of glucuronate residues from chondroitin A, B and C (Chondroitinase ABC) and retinoic acid treatment induced an inhibition of proteoglycan synthesis, whereas collagenase treatment did not. Collagenase activity was correlated with increased appearance of the CB11B epitope and type II collagen denaturation. By RT-PCR there was evidence of expression of altered collagen type IIA in purified collagenase treated tissues.

Assessment of the effects of age and joint disease on hydroxyproline and glycosaminoglycan concentrations in synovial fluid from the metacarpophalangeal joint of horses

OBJECTIVE

To assess the effects of age and joint disease on hydroxyproline and glycosaminoglycan (GAG) concentrations in synovial fluid from the metacarpophalangeal joint of horses and evaluate the association of those concentrations with severity of osteoarthritis and general matrix metalloproteinase (MMP) activity.

SAMPLE POPULATION

Synovial fluid was collected from the metacarpophalangeal joints of foals at birth (n = 10), 5-month-old foals (10), 11-month-old foals (5), and adult horses (73).

PROCEDURE

Hydroxyproline and GAG concentrations were determined in synovial fluid samples. The severity of osteoarthritis in adult joints was quantified by use of a cartilage degeneration index (CDI) and assessment of general MMP-activity via a fluorogenic assay.

RESULTS

Hydroxyproline and GAG concentrations in synovial fluid were highest in neonates and decreased with age. Concentrations reached a plateau in adults by 4 years and remained constant in healthy joints. In synovial fluid from osteoarthritic joints, hydroxyproline and GAG concentrations were not increased, compared with unaffected joints, but hydroxyproline were significantly correlated with the CDI and general MMP activity. There was no significant correlation between GAG concentration and CDI value or MMP activity.

CONCLUSIONS AND CLINICAL RELEVANCE

Changes in hydroxyproline concentration in synovial fluid appeared to indicate damage to collagen of the articular cartilage. In joints with osteoarthritis, the lack of high GAG concentration in synovial fluid and the absence of a significant correlation between GAG concentration and CDI values or MMP activity may severely limit the usefulness of this marker for monitoring equine joint disease.

Detection of collagen type II and proteoglycans in the synovial fluids of patients diagnosed with non-infectious knee joint synovitis indicates early damage to the articular cartilage matrix

OBJECTIVE

We have sought to determine if markers of proteoglycans and collagen type II (CII) degradation can be detected at an early stage following acute knee injury in the synovial fluid (SF) from a group of patients diagnosed with non-infectious knee joint synovitis (KJS). CII, proteoglycans and elastase activity in the SF from patients with KJS were compared to SF from patients with two chronic arthritis conditions: osteoarthritis (OA) and rheumatoid arthritis (RA) as well as normal SF controls.

METHODS

CII peptides were measured by sandwich ELISA using two monoclonal antibodies: 8:6:D8, a CII-specific antibody, and 14:7:D8 which binds to an amino acid sequence on CII as well as collagens type I, III and V. Epitope 9A4, a neo-epitope resulting from collagenase digestion of CI, CII, and CIII was measured by inhibition ELISA. Proteoglycans measurement included total sulfated glycosaminoglycans (sGAG) by dye-binding assay and 5-D-4 epitope, a keratan sulfate epitope, by inhibition ELISA. Elastase activity was measured colorimetircally using N-succinyl trialanine p-nitroanilide (SANA) substrate.

RESULTS

The quantified CII peptide concentrations by sandwich and inhibition ELISA were significantly higher in SF from patients with KJS (P<0.05) compared to SF from patients with OA, RA and normal aspirates. 5-D-4 and sGAG concentrations were significantly lower (P<0.05) in SF from patients with KJS compared to SF from patients with OA and RA. Elastase activity in SF from patients with KJS and RA were significantly higher (P<0.05) than SF from patients with OA. A significant correlation exists between elastase activity and 9A4 epitope concentration in SF from patients with KJS.

CONCLUSION

The elevated CII peptides concentrations in KJS SF compared to normal and OA aspirates indicate early signs of cartilage network damage. The low proteoglycans concentrations in SF from patients with KJS may indicate that injury is limited to the superficial zone of cartilage in the patient population studied. The high elastase activity in SF from patients with KJS and RA are linked to the high CII peptides concentration. The elastase activity in the SF from patients with KJS is due to the action of neutrophil elastase (NE) and collagenases, where both contribute to the destruction of the articular cartilage.

Biochemical change in joint fluid after isometric quadriceps exercise for patients with osteoarthritis of the knee

OBJECTIVE

The purpose of this study was to analyze the biochemical changes in the joint fluid, and pain relief resulting from isometric quadriceps exercise in patients with osteoarthritis of the knee.

DESIGN

Nineteen osteoarthritic knees in 17 patients with joint effusion were included. The patients performed isometric quadriceps exercise for 3 months. Isometric muscle torque at 30 and 60 degrees flexion, pain as measured using the visual analog scale and biochemical markers in joint fluid were evaluated before and after the exercise.

RESULTS

Pain score decreased from 3.9 to 2.3 after 12 weeks of exercise (P<0.001). Extension torque at 30 and 60 degrees knee flexion significantly increased from 4.7 to 6.9 kgm (47% increase, P<0.001) and from 10.8 to 12.6 kgm (17% increase, P<0.005) after 12 weeks of exercise. The molecular weight of hyaluronan increased from 2.11 to 2.40x10(6)(P<0.05) and the viscosity of joint fluid increased from 45.8 to 59.8 mPas after 12 weeks of exercise (P<0.05). Chondroitin 4-, 6-sulfate concentration in joint fluid decreased from 81.9 to 75.5 nmol/ml (P<0.05).

CONCLUSIONS

Isometric quadriceps exercise resulted in significant changes in joint fluid biochemical parameters, and these changes, at least in part, may explain the ameliorative effect of muscle exercise for osteoarthritis of the knee.

Age-related changes in the composition, the molecular stoichiometry and the stability of proteoglycan aggregates extracted from human articular cartilage

The heterogeneity of the components of proteoglycan aggregates, their stoichiometry within the aggregate and the aggregates' stability was investigated in normal human articular cartilage specimens (age-range newborn to 63 years). Proteoglycans were extracted from tissue by sequentially extracting them with PBS alone, PBS containing oligosaccharides of hyaluronan, and PBS containing solutions of increasing guanidinium chloride concentration (1 M, 2 M, 3 M and 4 M). A high proportion of each of the components of the proteoglycan aggregate, i.e. uronic acid, sulphated glycosaminoglycan, hyaluronan binding domain of aggrecan (G1-domain), link protein (LP) and hyaluronan, was extracted from immature cartilage by PBS alone and PBS containing oligosaccharides of hyaluronan. This was in marked contrast to adult cartilage, which required high concentrations of guanidinium chloride for the efficient extraction of these components. The molar ratios of total G1-domain:LP and the G1-domain associated with aggrecan:LP also differed markedly between immature and mature cartilage and between each of the sequential extracts. The concentration of LP was less than that of the G1-domain in all extracts of cartilage from individuals over 13 years, but this was particularly noticeable in the 1 M guanidinium chloride extracts, and it was surmised that a deficiency in LP produces unstable aggregates in situ. The fragmentation of LP, which is known to occur with advancing age, did not influence the extractability of LP, and fragments were present in each of the sequential extracts. Therefore the generally accepted model of proteoglycan aggregation presented in the literature, which is mostly derived from analysis of immature animal cartilage, cannot be used to describe the structure and organization of aggregates in adult human articular cartilage, where a heterogeneous population of complexes exist that have varying degrees of stability.

Use of joint fluid analysis for determining cartilage damage in osteonecrosis of the knee

OBJECTIVE

To assess the value of joint fluid analysis for determining cartilage degradation and prognosis in spontaneous osteonecrosis (ON) of the knee.

METHODS

Synovial fluid was obtained from 30 knees with spontaneous ON (26 medial femoral condyles, 4 medial tibial plateaus) as well as from 50 knees with medial compartmental osteoarthritis (OA) as a control. Levels of chondroitin 6-sulfate (C6S), C4S, and hyaluronic acid were measured with high-performance liquid chromatography. The lesion size, appearance of the articular cartilage, and results of magnetic resonance imaging (MRI) were compared with the results of joint fluid analysis.

RESULTS

The mean +/- SD level of C6S was 82.2 +/- 36.6 nmoles/ml in joint fluid from ON knees, which was significantly higher than the levels in knees with grade 2 (47.2 +/- 20.0 nmoles/ml) and grade 3 (55.8 +/- 29.2 nmoles/ml) OA. The C6S:C4S ratio was highest in lesions with mild articular changes and reflected the macroscopic alteration of cartilage overlying the ON lesion. The concentration of C6S in the 9 knees with lesions that covered > or = 40% of the condyle (99.0 +/- 32.9 nmoles/ml) was higher than that in the 17 knees with lesions that covered <40% of the condyle (67.2 +/- 31.7 nmoles/ml). Knees with bone marrow edema on MRI had a higher level of C6S than did knees with a fibrous-like appearance.

CONCLUSION

While radiologic staging was useful for indicating the size of the ON lesion, it was less valuable for determining articular cartilage damage. Joint fluid analysis may provide more precise information about articular cartilage degradation in ON, and the findings may also be of prognostic significance.

Cartilage-derived biomarkers of osteoarthritis in synovial fluid of dogs with naturally acquired rupture of the cranial cruciate ligament

OBJECTIVE

To compare synovial fluid biomarkers of cartilage metabolism in joints with naturally acquired or experimentally induced cranial cruciate ligament (CCL) rupture and determine correlations with stage and severity of disease in dogs.

ANIMALS

95 dogs with ruptured CCL, 8 dogs with experimentally ruptured CCL, and 24 healthy dogs.

PROCEDURES

Synovial fluid was assayed for chondroitin sulfate neo-epitopes 3B3(-) and 7D4 and glycosaminoglycan (GAG) concentration. Results were correlated with demographic data, duration of lameness, radiographic osteoarthritis score, and intra-articular lesions.

RESULTS

The 7D4 concentrations and 7D4:GAG in synovial fluid from joints with naturally acquired CCL rupture and experimental CCL transection were similar and significantly greater than values for healthy control joints. The 3B3(-) concentrations in the CCL-deficient groups were not significantly different, although only values in the naturally acquired CCL rupture group were significantly greater than those in the healthy control group. Within the naturally acquired CCL rupture group there was a significant correlation between 3B3(-) and 7D4 concentrations. However, there were no significant correlations between biomarker concentrations and continuous demographic or disease-related variables or differences in biomarker concentrations with different categories of disease.

CONCLUSIONS AND CLINICAL RELEVANCE

Synovial fluid biomarker concentrations were significantly increased in joints with secondary osteoarthritis associated with naturally acquired or experimental CCL rupture; however, lack of apparently simple relationships with demographic variables or stage or severity of disease limits their clinical usefulness.

Structure and function of aggrecan

Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan.

Synovial fluid studies in navicular disease

The purpose of this study was to investigate biochemical changes in synovial fluid in navicular disease, and to establish if synovial fluid from the distal interphalangeal joint (DIP) could be used diagnostically to assess alterations in the synovial fluid of the navicular bursa. Cartilage oligomeric matrix protein (COMP), total glycosaminoglycans (GAG), hyaluronan (HA), metalloproteinases 2 and -9 (MMP-2 and MMP-9) and total protein (TP) levels were determined in synovial fluids obtained from 18 navicular bursae and 35 DIP -joints from animals suffering from navicular disease, and the same synovial structures in 16 joints of horses with no evidence of abnormalities involving the foot. To avoid dilution effects, GAG/COMP, HA/COMP, MMP-2/ COMP and MMP-9/COMP ratios were also calculated for different synovial cavities. There was a good correlation, for COMP, GAG, HA, MMP-2 and TP levels, between synovial fluid from the navicular bursa and fluid from the DIP -joint in healthy animals. However, in animals with navicular disease, only COMP levels showed no difference between the navicular bursal fluid and the DIP-joint fluid concentration. Thus, enabling the use of COMP to standardise other biochemical concentration measurements from the synovial joint fluids. In horses with navicular disease, there was a significantly lower absolute concentration of GAG, and a significantly lower GAG/COMP ratio, in the synovial fluid of the navicular bursa and the DIP-joint compared to synovial fluid from the same joints from healthy horses. In contrast, the absolute HA concentration and HA/ COMP, MMP-2/COMP and MMP-9/COMP ratios were higher in synovial fluid from the DIP-joint of horses with navicular disease, and MMP-2 and MMP-9 relative activity levels and MMP-2/COMP and MMP-9/ COMP ratios were increased in fluid from navicular bursae in horses with navicular disease when compared to a control group.

Concentrations of chondroitin sulfate epitopes 3B3 and 7D4 in synovial fluid after intra-articular and extracapsular reconstruction of the cranial cruciate ligament in dogs

OBJECTIVE

To evaluate effects of intra-articular and extracapsular reconstruction of the cranial cruciate ligament (CCL) on metabolism of articular cartilage as reflected by concentrations of chondroitin sulfate epitopes 3B3 and 7D4 in synovial fluid.

ANIMALS

13 adult dogs.

PROCEDURE

Each dog underwent unilateral CCL transection (CCLT). One month after CCLT, sham CCL reconstruction (3 dogs), intra-articular CCL reconstruction (5), or extracapsular CCL reconstruction (5) was performed. Synovial fluid was collected by direct arthrocentesis from CCLT and contralateral stifle joints immediately before (time 0) and 1, 3, and 5 months after CCLT. Fluid was examined for concentrations of 3B3 and 7D4 epitopes and total sulfated glycosaminoglycan (GAG) content.

RESULTS

Concentrations of 3B3, 7D4, and GAG, 3B3:GAG, or 7D4:GAG in CCLT joints did not differ significantly among treatment groups nor in the ratios of these variables in CCLT joints to contralateral joints at 3 months. In a longitudinal analysis, concentrations of 3B3 and 7D4, 3B3:GAG, and 7D4:GAG in CCLT joints in all groups changed significantly with time, but we did not detect time X group interactions.

CONCLUSIONS AND CLINICAL RELEVANCE

Transection of CCL resulted in significant perturbation in articular cartilage metabolism as reflected by alterations in concentrations of 3B3 and 7D4 in synovial fluid. These changes over time were not significantly influenced by method of CCL reconstruction. We did not find evidence that surgical stabilization of CCL-deficient joints by intra-articular or extracapsular techniques had any effect on preventing alterations in composition of synovial fluid that have been associated with secondary osteoarthritis.

Effects of an orally administered mixture of chondroitin sulfate, glucosamine hydrochloride and manganese ascorbate on synovial fluid chondroitin sulfate 3B3 and 7D4 epitope in a canine cruciate ligament transection model of osteoarthritis

OBJECTIVE

To evaluate effects of an orally administered mixture of chondroitin sulfate, glucosamine hydrochloride and manganese ascorbate (CS-G-M) on articular cartilage metabolism in dogs with cranial cruciate ligament (CCL) deficient and reconstructed knees, as reflected by concentrations of synovial fluid 3B3, 7D4 and total sulfated glycosaminoglycan (GAG).

METHODS

Sixteen adult dogs that underwent unilateral CCL transection were randomized into four groups. Thereafter, group I (N=3) had a sham CCL reconstruction, group II (N=3) had CS-G-M and sham CCL reconstruction, group III (N=5) had CCL reconstruction, and group IV (N=5) had CS-G-M and CCL reconstruction. Synovial fluid collected at 0, 1, 3 and 5 months was examined by ELISA for 3B3 and 7D4 epitope, and by DMMB assay for total GAG.

RESULTS

Synovial fluid from CCL transected knees of CS-G-M treated dogs contained significantly elevated concentrations of 3B3 (P=0.029), 7D4 (P=0.036) and 7D4/GAG (P=0.007) in comparison to controls, in a cross-sectional analysis at 3 months. Furthermore, 7D4 and 7D4/GAG concentrations remained significantly elevated (P=0.012) in CCL transected knees of CS-G-M treated dogs over the 5 month period. However, when epitope concentrations were expressed as a ratio of CCL-transected to contralateral non-operated knee, treatment effect of CS-G-M was no longer significant. Reconstruction of the CCL had no significant effect on synovial fluid epitope.

CONCLUSIONS

Administration of CS-G-M was associated with altered concentrations of 3B3 and 7D4 epitope in synovial fluid, suggesting that these compounds may act to modulate articular cartilage matrix metabolism in vivo.

Cartilaginous extracellular matrix of failed massive osteoarticular allografts

Osteoarticular defects present a reparative challenge to orthopaedic surgeons. Osteoarticular allografts provided a promising solution. Unfortunately, many of these allografts failed secondary to articular cartilage degeneration. To determine the role of the extracellular matrix in graft failure, the authors have characterized the proteoglycan content of cartilage from grafts that failed early (2-4 years) and grafts that failed late (approximately 8 years) and compared this with normal cartilage. Cartilage was removed from all specimens. Proteoglycans were extracted and characterized based on molecular size and reactivity with antibodies. Protein and proteoglycan contents of early and late failure grafts were significantly lower per gram of tissue than normal cartilage. Patterns of distribution of associated proteoglycans and dissociated proteoglycans differed between early and later failure grafts and both were different from normal cartilage. Early failure cartilage contained less keratan sulfate proteoglycan with a different distribution of molecular sizes. Chondroitin sulfate epitopes showed discordance between early failure and normal cartilage and concordance between normal and late failure cartilage. These data show distinct differences in proteoglycan content between failed graft and normal cartilage and also between cartilage from grafts that failed early and late. Proteoglycan content and glycosaminoglycan substitution were altered in all specimens. Maintenance of a more normal extracellular matrix will be required to preserve function in these grafts for longer periods.

Synovial fluid chondroitin sulphate epitopes 3B3 and 7D4, and glycosaminoglycan in human knee osteoarthritis after exercise

OBJECTIVE

Walking exercise alleviates some symptoms, such as pain, in patients with mild to moderate knee osteoarthritis (OA). However, a major concern is that weightbearing exercise on osteoarthritic joints may exacerbate articular cartilage degradation. Loading of proteoglycan depleted articular cartilage in vitro increased expression of the chondroitin sulphate epitope 3B3, suggesting that loading may influence metabolism of osteoarthritic cartilage. This study aimed at evaluating the effects of walking exercise on articular cartilage metabolism in patients with knee OA, as reflected by changes in concentrations of synovial fluid markers.

METHODS

Thirty elderly patients with knee OA (Kellgren-Lawrence grades II to IV) were randomly allocated to control (n = 15) and 12 week exercise (n = 15) groups. Synovial fluid obtained from 21 of the patients at time zero and after 12 weeks was examined by enzyme linked immunosorbent assay (ELISA) for the chondroitin sulphate epitopes 3B3 and 7D4, and by a dye binding assay with 1, 9-dimethylmethylene blue for total sulphated glycosaminoglycan (GAG) concentrations. The 3B3/GAG and 7D4/GAG ratios were calculated.

RESULTS

No significant changes in concentrations of 3B3, 7D4, GAG, 3B3/GAG, or 7D4/GAG between time zero and 12 weeks were found in either group. However, there were significant declines in 3B3 (p=0. 001), GAG (p=0.007), and the 3B3/GAG ratio (p=0.049) with aging.

CONCLUSION

Twelve weeks of walking exercise had no demonstrable adverse effects on articular cartilage metabolism, as reflected by the concentrations of synovial fluid GAG or the chondroitin sulphate epitopes 3B3 and 7D4.

Nitric oxide inhibits aggrecan degradation in explant cultures of equine articular cartilage

Arthroses are debilitating diseases of articular joints which result in erosion of the cartilage extracellular matrix. Nitric oxide (NO) is a major component of the inflammatory response, and has been implicated as a mediator of some of the effects of the proinflammatory cytokine, interleukin-1 (IL-1). In this study, we investigated the role of NO in the regulation of proteoglycan degradation in equine articular cartilage. NO fully mediated the suppressive effect of IL-1 on proteoglycan synthesis. However, NO was also antagonistic to proteoglycan degradation, irrespective of whether degradation was initiated by 10 ng/ml IL-1 or 1 micromol/l all-trans retinoic acid (RA) which (unlike IL-1) does not elevate NO production. This was confirmed using the NO donor 2,2'-(hydroxynitrosohydrazono) bis-ethanamine (DETA-NONOate) and the iNOS inhibitor L-N5-iminoethyl ornithine (dihydrochloride) (L-NIO). The G1 fragments of aggrecan were detected in the media and extracts of cartilage explant cultures treated with all-trans RA, DETA-NONOate and L-NIO. The presence of exogenous NO in culture resulted in a decrease in the appearance of the 'aggrecanase' cleavage epitope. Therefore, changes in the appearance of the G1 fragment expressing the 'aggrecanase' cleavage epitope in the media emulated the glycosaminoglycan loss from the tissue. These results lend further support to the hypothesis that NO has an anticatabolic role in equine cartilage proteoglycan degradation, and suggest that this may be mediated by the regulation of 'aggrecanase' activity. Therefore, any pharmacological intervention using NO as a target must take into account both its catabolic and anticatabolic roles in joint tissue turnover.

Monopolar radiofrequency energy effects on joint capsular tissue: potential treatment for joint instability. An in vivo mechanical, morphological, and biochemical study using an ovine model

The purpose of this study was to evaluate the thermal effect of monopolar radiofrequency energy, a potential treatment means for joint instability, on the mechanical, morphologic, and biochemical properties of joint capsular tissue in an in vivo ovine model. The energy was applied arthroscopically to the synovial surface of the femoropatellar joint capsule of 24 sheep. The sheep were sacrificed at 0, 2, 6, and 12 weeks after surgery (6 per group). Monopolar radiofrequency energy initially caused a significant decrease in tissue stiffness and an increase in tissue relaxation properties, followed by gradual improvement in the tissue's mechanical properties by 6 weeks after surgery. Microscopic examination illustrated that radiofrequency energy initially caused collagen hyalinization and cell necrosis, followed by active tissue repair. Biochemical analysis revealed that treated collagen was significantly more trypsin-susceptibile than untreated collagen at 0 and 2 weeks after surgery, indicating early collagen denaturation. This study demonstrated that this treatment initially caused a significantly deleterious effect on the mechanical properties of the joint capsule, which was associated with partial denaturation of joint capsular tissue. This was followed by gradual improvement of the mechanical, morphologic, and biochemical properties of the tissue over time.

Serum levels of hyaluronan, antigenic keratan sulfate, matrix metalloproteinase 3, and tissue inhibitor of metalloproteinases 1 change predictably in rheumatoid arthritis patients who have begun activity after a night of bed rest

OBJECTIVE

To evaluate whether and how moderate physical activity following a night of rest influences serum levels of matrix metalloproteinase 3 (MMP-3), tissue inhibitor of metalloproteinases 1 (TIMP-1), antigenic keratan sulfate (Ag KS), and hyaluronan (HA) in 10 normal subjects and 38 patients with rheumatoid arthritis (RA).

METHODS

Blood was obtained from 20 RA patients before they arose from a night's sleep, and again 1 and 4 hours after they had begun to perform moderate physical activity. Another 18 RA patients remained in bed and blood was sampled at the same time periods. Serum levels of MMP-3, TIMP-1, Ag KS, and HA were measured by enzyme-linked immunosorbent assay. Clinical activity was evaluated by the Lansbury index.

RESULTS

Both in normal subjects and in RA patients who did not remain in bed throughout the period of blood sampling, levels of HA, Ag KS, and MMP-3 increased significantly during the first hour after the subjects arose: the increase in HA and Ag KS correlated with the Lansbury index in the RA group. Three hours later, levels of Ag KS had dropped to baseline values in both groups of subjects. Levels of HA remained significantly and moderately elevated in the RA group but not in the control group, while levels of MMP-3 did not drop significantly in either group. In contrast, levels of HA, Ag KS, and MMP-3 did not change significantly in RA patients who had remained in bed. Unlike the other markers, the levels of TIMP-1 remained unchanged at the different time periods in all 3 groups studied.

CONCLUSION

Significant changes in serum levels of some metabolic markers occur during the first hour after one arises from a night of sleep, especially in patients with RA. Measurement of the magnitude of these changes at different times in individual patients provides very different information about metabolic changes occurring in joint tissue than does measurement of the level of the markers at a single time point, as is usually currently reported.

Relationship of matrix metalloproteinases and their inhibitors to cartilage proteoglycan and collagen turnover: analyses of synovial fluid from patients with osteoarthritis

OBJECTIVE

To determine the relationship between matrix metalloproteinases (MMPs), their inhibitors, and the turnover of matrix molecules in articular cartilage from patients with osteoarthritis (OA).

METHODS

Synovial fluid samples were collected from the knees of 54 patients with OA. Radiographic evaluations and magnetic resonance imaging were performed on the knees of 34 OA patients to classify the stage of the disease. Biochemical analyses and immunoassays were used to measure the concentrations of MMP-1, MMP-3, tissue inhibitor of metalloproteinases 1 (TIMP-1), TIMP-2, the disaccharide of hyaluronic acid, the proteoglycan glycosaminoglycan disaccharides of chondroitin 4-sulfate (delta di-CS4) and chondroitin 6-sulfate (delta di-CS6), the 846 epitope on chondroitin sulfate of cartilage proteoglycan aggrecan (putative biosynthetic marker), the keratan sulfate (KS) epitope of aggrecan (putative degradation marker), and the C-propeptide of cartilage type II procollagen (CPII) (biosynthetic marker).

RESULTS

The concentration of TIMP-1 was directly correlated with the levels of MMP-1 and MMP-3 (both were also correlated with each other), confirming earlier results. There was an inverse correlation between the delta di-CS6:delta di-CS4 ratio and the concentration of MMP-3. The level of delta di-CS6 was correlated with that of the KS epitope, and to a lesser degree, with that of the 846 epitope (the latter was also correlated with the level of delta di-CS4). The concentration of TIMP-1 correlated with that of the 846 epitope, whereas TIMP-2 levels correlated with those of CPII. There were significantly lower concentrations of delta di-CS6, delta di-CS4, the 846 epitope, and CPII in synovial fluid from patients with late-stage OA.

CONCLUSION

These observations suggest a link between proteolysis and inhibitor concentrations in OA cartilage. Production of TIMPs appears to be individually linked to the synthesis of specific cartilage molecules. The reduction in the amount of cartilage-matrix structural components suggests that there is a measurable loss of cartilage in the late stages of the disease, as suggested previously. The resultant composition of the cartilage suggests that the loss may primarily involve "resident" molecules originally present in healthy cartilage.

The potential role of doxycycline in the treatment of osteoarthritis of the temporomandibular joint

Collagenase and gelatinase are matrix metalloproteinases (MMPs) which play an important role in tissue destruction in arthritic joints. Studies have demonstrated that tetracyclines can inhibit MMPs and prevent tissue destruction independent of their antimicrobial activity. The purpose of this pilot study is to assess the potential therapeutic role of Doxycycline in patients with advanced osteoarthritis of the temporomandibular joint (TMJ). This ongoing investigation includes patients with a diagnosis of osteoarthritis of the TMJ based on clinical and diagnostic imaging findings, symptoms (localized TMJ pain, limited mobility, dysfunction) for a minimum of 36 months, and failure of previous non-surgical and surgical modalities to alleviate the symptoms. A synovial fluid sample is collected by a saline injection and aspiration technique, followed by diagnostic arthroscopy. Patients are placed on Doxycycline 50 mg BID for three months and then undergo repeat diagnostic arthroscopy and synovial fluid collection. The samples are stored at -80 degrees C. Collagenase activity is determined by a combination of SDS-polyacrylamide gel electrophoresis and fluorography and calculated based on the percentage of collagen alpha chains that are degraded into alphaA breakdown products. Three patients have completed the three-month course of Doxycycline thus far, and 5 joints with osteoarthritis have been analyzed. All patients were female (mean age = 35, mean duration of symptoms = 132 months) and had undergone previous bilateral arthroscopies. One patient had undergone unilateral arthroplasty. The mean collagenase activity showed 55% collagen lysis prior to Doxycycline treatment and 19% after three months of therapy. The mean gelatinase activity was 28% prior to Doxycycline treatment and 7% after three months of therapy. The mean interincisal opening was 33 mm initially and 41 mm after three months of Doxycycline. Subjectively, two of the three patients reported significant improvement in their overall symptoms, which they had not experienced over the previous three years. One patient did not experience any change in symptoms, in spite of a marked reduction in collagenase activity from 86.4% to 9.6%. Because of the very small numbers of patients enrolled in this pilot study so far, no statistically significant differences could be appreciated. However, the dramatic reduction in collagenase activity in these patients, with a long history of TMJ symptoms from osteoarthritis, suggests the potential promising role of Doxycycline in the management of osteoarthritis, and further investigation is warranted.

Human aggrecan keratan sulfate undergoes structural changes during adolescent development

Alkaline borohydride-reduced keratan sulfate chains were isolated from human articular cartilage aggrecan from individuals of various ages (0-85 years old). The chains were structurally characterized using 1H NMR spectroscopy, gel permeation chromatography, and oligosaccharide profiling (after digestion with the enzymes keratanase and keratanase II). The results show that from birth to early adolescence (0-9 years) the levels of alpha(1-3)-fucosylation, alpha(2-3)-sialylation, and galactose sulfation increase. Also, the weight-average molecular weight of the chains increases. During maturation (9-18 years) the levels of fucosylation and galactose sulfation continue to increase and alpha(2-6)-sialylation of the chains occurs. In adult life (18-85 years) there is little change in the weight-average molecular weight of the chains, and the levels of fucosylation, sialylation, and sulfation remain fairly constant.

Measurement of serum and synovial fluid keratan sulphate and antibody to collagen type II in equine osteoarthritis

Keratan sulphate (KS) concentration and anticollagen type II antibody levels were measured in the serum and synovial fluid (SF) of clinically normal horses and horses with osteoarthritis (OA). Serum KS in OA was significantly higher than that in normal horses, while no significant difference was found in KS levels of SF between normal and OA. Assays of antibody to collagen type II showed no significant increase in sera and SF of OA. It was suggested that levels of serum KS would be of value in the pathological detection of OA in the joint, although there was no evidence that the measurable autoimmunity to collagen antigens would reflect the process of OA.

Macromolecular diffusion of biological polymers measured by confocal fluorescence recovery after photobleaching

Fluorescence recovery after photobleaching with an unmodified confocal laser scanning microscope (confocal FRAP) was used to determine the diffusion properties of network forming biological macromolecules such as aggrecan. The technique was validated using fluorescein isothiocyanate (FITC)-labeled dextrans and proteins (molecular mass 4-2000 kDa) at 25 degrees C and with fluorescent microspheres (207 nm diameter) over a temperature range of 5-50 degrees C. Lateral diffusion coefficients (D) were independent of the focus position, and the degree and extent of bleach. The free diffusion coefficient (Do) of FITC-aggrecan determined by confocal FRAP was 4.25 +/- 0.6 x 10(-8) cm2 s-1, which is compatible with dynamic laser light scattering measurements. It appeared to be independent of concentration below 2.0 mg/ml, but at higher concentrations (2-20 mg/ml) the self-diffusion coefficient followed the function D = Do(e)(-Bc). The concentration at which the self-diffusion coefficient began to fall corresponded to the concentration predicted for domain overlap. Multimolecular aggregates of aggrecan ( approximately 30 monomers) had a much lower free diffusion coefficient (Do = 6.6 +/- 1.0 x 10(-9) cm2 s-1) but showed a decrease in mobility with concentration of a form similar to that of the monomer. The method provides a technique for investigating the macromolecular organization in glycan-rich networks at concentrations close to those found physiologically.

Connective tissue markers of rheumatoid arthritis

Rheumatoid arthritis (RA) is a common systemic autoimmune disorder of unknown aetiology. The most common outcome of RA is a progressive development of joint destruction and deformity. Early introduction of disease-modifying antirheumatic drugs seems important for prevention of the long term injuries of articular cartilage and bone. Early diagnosis and selection of patients with rapidly progressive disease therefore is of clinical significance. Routine laboratory tests are valuable in monitoring for renal, hepatic and haematological side effects of medical treatment. Determination of rheumatoid factor contributes to the classification of arthritis as RA, and acute phase reactants are useful for quantifying and comparing the level of inflammatory activity in the course of a given patient. There is, however, a lack of sensitive and specific biochemical markers for RA, and frontline biochemical research is devoted to characterizing molecules which are of diagnostic and prognostic value, as well as molecules which are indicators of the degree of joint cartilage and bone destruction. The present survey summarizes current knowledge concerning possible tissue-specific marker molecules of RA.

Glycosaminoglycan components in temporomandibular joint synovial fluid as markers of joint pathology

PURPOSE

This study investigated the correlation between temporomandibular joint (TMJ) disease and the composition of glycosaminoglycans (GAGs) components in the synovial fluid (SF).

MATERIALS AND METHODS

Synovial fluid (SF) was obtained from 30 TMJs of 28 female patients diagnosed as having a displaced disc with reduction (WR) (seven joints), a displaced disc without reduction (WOR) (13 joints), osteoarthritis (OA) (five joints), or rheumatoid arthritis (RA) (five joints) by MR imaging and clinical examination. After the SF was directly aspirated, It was digested with chondroitinase ABC and hyaluronidase, and the concentration of unsaturated disaccharide isomers of chondroitin 6-sulfate (delta di-6S), chondroitin 4-sulfate (delta di-4S) and hyaluronic acid (delta di-HA) were measured by high-performance liquid chromatography (HPLC) combined with fluorometry. The ratio of delta di-6S or delta di-4S to delta di-HA, and delta di-6S to delta di-4S, were calculated.

RESULTS

There were no significant differences in concentrations of delta di-6S, delta di-4S, or delta di-HA among the groups. The ratio of delta di-6S to delta di-4S was 2.7 +/- 1.4 in OA, 2.6 +/- 0.9 in joints with WOR, 2.9 +/- 1.2 in joints with WR, and 1.3 +/- 0.4 in RA synovial fluid. Differences in the delta di-6S: delta di-4S ratio between RA and the other conditions were statistically significant (P < .05).

CONCLUSION

These results suggest that the delta di-6S:delta di-4S ratio in the synovial fluid of the TMJ reflects the proteoglycan metabolism of the joint tissues, particularly of the articular cartilage and synovial tissue. This ratio could be used to diagnose joint diseases and to predict articular cartilage destruction or synovial proliferation caused by these diseases.