New biochemical insights into the pathogenesis of osteoarthritis and the role of laboratory investigations in clinical assessment

Pathomechanics Underlying Femoroacetabular Impingement Syndrome: Theoretical Framework to Inform Clinical Practice

Over the last decade, there has been a marked increase in attention to, and interest in, femoroacetabular impingement syndrome (FAIS). Despite continued efforts by researchers and clinicians, the development, progression, and appropriate treatment of FAIS remains unclear. While research across various disciplines has provided informative work in various areas related to FAIS, the underlying pathomechanics, time history, and interaction between known risk factors and symptoms remain poorly understood. The purpose of this perspective is to propose a theoretical framework that describes a potential pathway for the development and progression of FAIS. This paper aims to integrate relevant knowledge and understanding from the growing literature related to FAIS to provide a perspective that can inform future research and intervention efforts.

Distinct tribological endotypes of pathological human synovial fluid reveal characteristic biomarkers and variation in efficacy of viscosupplementation at reducing local strains in articular cartilage

OBJECTIVE

Viscosupplementation has been used for decades to treat mild to moderate osteoarthritis, yet it is unknown if the lubricating function of different pathological synovial fluids (SF) vary, or if they respond differentially to viscosupplementation. The objectives of this study were to (i) evaluate the friction coefficients and induced shear strains in articular cartilage when lubricated with pathological SF, (ii) identify the effect of hyaluronic acid (HA) supplementation on friction coefficients and shear strains, and (iii) identify SF biomarkers that correlate with lubricating function.

METHOD

Human pathological SF was grouped by white blood cell count (inflammatory: >2000 cells/mm³, n = 6; non-inflammatory: <2000 cells/mm³, n = 6). Compositional analyses for lubricin and cytokines were performed. Friction coefficients and local tissue shear strain measurements were coupled using new, microscale rheological analyses by lubricating neonatal bovine cartilage explants with SF alone and in a 1:1 ratio with HA (Hymovis®).

RESULTS

Friction coefficients were not significantly different between the inflammatory and non-inflammatory pathologies (p = 0.09), and were poorly correlated with peak tissue strains at the cartilage articular surface (R² = 0.34). A subset of inflammatory SF samples induced higher tissue strains, and HA supplementation was most effective at lowering friction and tissue strains in this inflammatory subset. Across all pathologies there were clear relationships between polymorphonuclear neutrophil (PMN), IL-8, and lubricin concentrations with cartilage tissue strains.

CONCLUSION

These results suggest that pathological SF is characterized by distinct tribological endotypes where SF lubricating behaviors are differentially modified by viscosupplementation and are identifiable by biomarkers.

Consensus recommendations for managing osteoarthritic pain with topical NSAIDs in Asia-Pacific

Osteoarthritis prevalence is expected to increase markedly in the Asia-Pacific region due to rapid population aging. Identifying effective and safe therapeutic options to manage osteoarthritic pain is viewed as a priority. The Asia-Pacific Experts on Topical Analgesics Advisory Board developed consensus statements for use of topical NSAIDs in musculoskeletal pain. Evidence supporting these statements in osteoarthritic pain was reviewed. Best available evidence indicates that topical NSAIDs have a moderate effect on relief of osteoarthritic pain, comparable to that of oral NSAIDs but with a better risk-to-benefit ratio. International clinical practice guidelines recommend topical NSAIDs on par with or ahead of oral NSAIDs for pain management in patients with knee and hand osteoarthritis, and as the first-line choice in persons aged ≥75 years.

Protective effect of Shenmai injection on knee articular cartilage of osteoarthritic rabbits and IL-1β-stimulated human chondrocytes

Shenmai injection (SMI) has been widely used as a therapy to treat a number of diseases. However, its anti-osteoarthritic properties have not yet been fully investigated. In the present study, the protective effect of SMI on knee articular cartilage of anterior cruciate ligament transected rabbits and interleukin-1β (IL-1β)-stimulated human chondrocytes was investigated. For the in vivo study, knee osteoarthritis (KOA) was induced in female New Zealand white rabbits by anterior cruciate ligament transection (ACLT) in the knee of right hind limb. Rabbits either underwent sham surgery or ACLT surgery. Out of the rabbits receiving ACLT surgery, half of the rabbits received one 0.3 ml Shenmai intra-articular injection in the knee per week for four weeks, following ACLT surgery. The other rabbits received the same volume of normal saline solution. The cartilage was subsequently collected for histological evaluation. For the in vitro study, cultured human chondrocytes were treated with 10 ng/ml IL-1β in the presence or absence of 5 and 2% (v/v) SMI for 24 h. Nitric oxide (NO) and prostaglandin E2 (PGE2) levels in cell culture supernatant were assessed using a Griess reaction and ELISA respectively. The mRNA expression of cyclooxgenase-2 (COX-2), inducible nitric oxide synthase (iNOS), matrix metalloproteinase (MMP)-1, MMP-13 and tissue inhibitors of metalloproteinase-1 (TIMP-1) in chondrocytes were detected by reverse transcription-quantitative polymerase chain reaction. The results of the current study revealed that treatment with SMI ameliorated cartilage degradation in the ACLT rabbit model, and decreased levels of NO and PGE2. Furthermore, treatment with SMI decreased levels of COX-2, iNOS, MMP-1 and MMP-13 mRNA expression and increased TIMP-1 mRNA expression in IL-1β-stimulated human chondrocytes. These results indicate that SMI suppresses inflammation and ameliorated cartilage degradation, making it a potential and promising therapeutic option to treat KOA.

Muscle force and movement variability before and after total knee arthroplasty: A review

Variability in muscle force output and movement variability are important aspects of identifying individuals with mobility deficits, central nervous system impairments, and future risk of falling. This has been investigated in elderly healthy and impaired adults, as well as in adults with osteoarthritis (OA), but the question of whether the same correlations also apply to those who have undergone a surgical intervention such as total knee arthroplasty (TKA) is still being investigated. While there is a growing body of literature identifying potential rehabilitation targets for individuals who have undergone TKA, it is important to first understand the underlying post-operative impairments to more efficiently target functional deficits that may lead to improved long-term outcomes. The purpose of this article is to review the potential role of muscle force output and movement variability in TKA recipients. The narrative review relies on existing literature in elderly healthy and impaired individuals, as well as in those with OA before and following TKA. The variables that may predict long-term functional abilities and deficits are discussed in the context of existing literature in healthy older adults and older adults with OA and following TKA, as well as the role future research in this field may play in providing evidence-based data for improved rehabilitation targets.

Inhibitory effect of a propolis on di-n-propyl disulfide or n-hexyl salycilate-induced skin irritation, oxidative stress and inflammatory responses in mice

PURPOSE

Thermal imaging has been utilised, both preclinically and clinically, as a tool for assessing inflammation. Psoriasis is a chronic inflammatory skin disease characterised by hyperkeratosis, dermal inflammatory infiltrate and increased angiogenesis. The aim of the present study was to assess the usefulness of thermography in psoriatic lesion regression after topical treatment with bee propolis, recognised as potent antioxidants and anti-inflammatory agents.

METHODS

We monitored the inflammation process induced by irritants such as n-Hexyl salycilate (HXS) or Di-n-Propyl Disulfide (PPD) by histopatological assessment of the skin, thermographic scanning, total number of inflammatory cells in the peritoneal cavity, differential analysis of cells in the peritoneal cavity, macrophage spreading index, haematological and biochemical parameters, frequencies of micronucleated reticulocytes, lipid peroxidation and glutathione assay in the skin.

RESULTS

Topically applied ethanolic extract of propolis (EEP) with HXS or PPD reduced the lipid peroxidation in the skin and total number of inflammatory cells in the skin and peritoneal cavity, functional activity of macrophages, the number of micronuclei in mouse peripheral blood reticulocytes and enzymatic activity of ALP and AST.

CONCLUSION

These results demonstrate that topical application of EEP may improve psoriatic-like skin lesions by suppressing functional activity of macrophages and ROS production. Taken together, it is suggested that EEP can safely be utilised in the prevention of psoriasis-related inflammatory changes without causing any toxic effect.

Elevation in circulating biomarkers of cartilage damage and inflammation in athletes with femoroacetabular impingement

BACKGROUND

Femoroacetabular impingement (FAI) is one of the most common causes of early cartilage and labral damage in the nondysplastic hip. Biomarkers of cartilage degradation and inflammation are associated with osteoarthritis. It was not known whether patients with FAI have elevated levels of biomarkers of cartilage degradation and inflammation.

HYPOTHESIS

Compared with athletes without FAI, athletes with FAI would have elevated levels of the inflammatory C-reactive protein (CRP) and cartilage oligomeric matrix protein (COMP), a cartilage degradation marker.

STUDY DESIGN

Controlled laboratory study.

METHODS

Male athletes with radiographically confirmed FAI (n = 10) were compared with male athletes with radiographically normal hips with no evidence of FAI or hip dysplasia (n = 19). Plasma levels of COMP and CRP were measured, and subjects also completed the Short Form-12 (SF-12) and Hip Disability and Osteoarthritis Outcome Score (HOOS) surveys.

RESULTS

Compared with controls, athletes with FAI had a 24% increase in COMP levels and a 276% increase in CRP levels as well as a 22% decrease in SF-12 physical component scores and decreases in all of the HOOS subscale scores.

CONCLUSION

Athletes with FAI demonstrate early biochemical signs of increased cartilage turnover and systemic inflammation.

CLINICAL RELEVANCE

Chondral injury secondary to the repetitive microtrauma of FAI might be reliably detected with biomarkers. In the future, these biomarkers might be used as screening tools to identify at-risk patients and assess the efficacy of therapeutic interventions such as hip preservation surgery in altering the natural history and progression to osteoarthritis.

Changes in circulating biomarkers of muscle atrophy, inflammation, and cartilage turnover in patients undergoing anterior cruciate ligament reconstruction and rehabilitation

BACKGROUND

After anterior cruciate ligament (ACL) reconstruction, there is significant atrophy of the quadriceps muscles that can limit full recovery and place athletes at risk for recurrent injuries with return to play. The cause of this muscle atrophy is not fully understood.

HYPOTHESIS

Circulating levels of proatrophy, proinflammatory, and cartilage turnover cytokines and biomarkers would increase after ACL reconstruction.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Patients (N = 18; mean age, 28 ± 2.4 years) underwent surgical reconstruction of the ACL after a noncontact athletic injury. Circulating levels of biomarkers were measured along with Short Form-12, International Knee Documentation Committee, and objective knee strength measures preoperatively and at 6 postoperative visits. Differences were tested using repeated-measures 1-way analysis of variance.

RESULTS

Myostatin, TGF-β, and C-reactive protein levels were significantly increased in the early postoperative period and returned to baseline. Cartilage oligomeric matrix protein levels decreased immediately after surgery and then returned to baseline. CCL2, CCL3, CCL4, CCL5, EGF, FGF-2, IGF-1, IL-10, IL-1α, IL-1β, IL-1ra, IL-6, myoglobin, and TNF-α were not different over the course of the study.

CONCLUSION

An increase in potent atrophy-inducing cytokines and corresponding changes in knee strength and functional scores were observed after ACL reconstruction.

CLINICAL RELEVANCE

Although further studies are necessary, the therapeutic inhibition of myostatin may help prevent the muscle atrophy that occurs after ACL reconstruction and provide an accelerated return of patients to sport.

Epigallocatechin-3-gallate reduces inflammation induced by calcium pyrophosphate crystals in vitro

Although osteoarthritis (OA) is defined as a cartilage disease, synovitis involving mononuclear cell infiltration and overexpression of proinflammatory mediators is common in early and late OA. Calcium crystals deposition is thought to be a factor that likely contributes to synovial inflammation. In recent years, significant interest has emerged in the beneficial health effects attributed to the green tea polyphenols and in particular to epigallocatechin-3-gallate (EGCG). It has been demonstrated that some of the actions of EGCG are linked to its ability to interfere with cell membranes. The objective of this study was to evaluate the influence of EGCG in some inflammatory aspects of OA and whether EGCG is able to interfere with membrane organization. We assessed the effect of EGCG on the production of proinflammatory cytokines and chemokines released by human fibroblast-like synoviocytes (FLS) and THP-1 cells stimulated with calcium pyrophosphate (CPP) crystals in presence of methyl-β-cyclodextrin (MβCD), a cholesterol-removing agent that disturbs lipid raft structures. The chemotactic effect of culture supernatants was also evaluated. EGCG inhibited interleukin (IL)-1β, transforming growth factor beta, IL-8, and chemokine (C–C motif) ligand 2 (CCL2) release by stimulated FLS and/or THP-1 cells in a dose-dependent manner. Supernatants of CPP-stimulated cells induced the migration of neutrophils and mononuclear cells which decreased in a dose-dependent manner in the presence of EGCG. EGCG increased cell viability when added to THP-1 cells treated with MβCD. Furthermore, MβCD enhanced the inflammatory response to CPP crystals increasing IL-8 and CCL2 secretion which was inhibited by EGCG in a dose-dependent manner. This study showed that EGCG is able to reduce the inflammatory response induced by CPP crystals in vitro. The identification of EGCG as dietary supplement capable of affording protection or modulating the inflammatory response to CPP crystals may have important implications in the prevention and treatment of OA and crystal-related arthropathies.

Serological markers of erosive hand osteoarthritis

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

Comparison between hyaluronic acid and platelet-rich plasma, intra-articular infiltration in the treatment of gonarthrosis

BACKGROUND

Arthrosis is particularly prevalent in the knee. Infiltration treatment for gonarthrosis is among the most widely used techniques in orthopaedic practice.

PURPOSE

To compare the clinical response of hyaluronic acid (HA) and platelet-rich plasma (PRP) treatment in 2 groups of patients affected by gonarthrosis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 120 patients affected by clinically and radiographically documented gonarthrosis were included in this study. The gonarthrosis was graded using the Kellgren-Lawrence radiographic classification scale. The 120 patients were randomized into 2 study groups in a 1:1 ratio: 60 patients received 4 intra-articular injections of PRP (specifically, autologous conditioned plasma [ACP], 5.5 mL), and 60 patients received 4 intra-articular injections of HA (20 mg/2 mL). An unblinded physician performed infiltration once a week for 4 weeks into the knee affected by clinically relevant gonarthrosis (in both groups). All patients were evaluated with the Western Ontario and McMaster (WOMAC) score before the infiltration and at 4, 12, and 24 weeks after the first injection.

RESULTS

Treatment with a local injection of ACP had a significant effect shortly after the final infiltration and a continuously improving sustained effect up to 24 weeks (WOMAC score, 65.1 and 36.5 in the HA and ACP groups, respectively; P < .001), where the clinical outcomes were better compared with the results with HA. In the HA group, the worst results were obtained for grade III gonarthrosis, whereas the clinical results obtained in the ACP group did not show any statistically significant difference in terms of the grade of gonarthrosis. The mean WOMAC scores for grade III gonarthrosis were 74.85 in the HA group and 41.20 in the ACP group (P < .001).

CONCLUSION

Treatment with ACP showed a significantly better clinical outcome than did treatment with HA, with sustained lower WOMAC scores. Treatment with HA did not seem to be effective in the patients with grade III gonarthrosis.

Significance of C-reactive protein in osteoarthritis and total knee arthroplasty outcomes

BACKGROUND

The relationship between systemic inflammatory processes to total knee arthroplasty (TKA) outcomes remains unclear. This study investigates the relationship between serum high-sensitivity C-reactive protein (hs-CRP) and functional outcomes post-TKA.

METHODS

A total of 31 patients with osteoarthritis (OA) who underwent TKA were enrolled in the study; 15 with hs-CRP ≤1.0 mg/l (low hs-CRP group) and 16 subjects with hs-CRP ≥4.0 mg/l (high hs-CRP group). During surgery, synovium and bone sections were sequestered, formalin-fixed, and paraffin embedded for slide preparation. Tissue sections were stained with hematoxylin and eosin and analyzed using a light microscope. A total of 12 cytokines were measured in synovial fluid samples from the knee joint at time of surgery and analyzed using the Luminex Multi-Analyte Profiling System. Relationships between cytokines and hs-CRP were assessed using Spearman correlation coefficients. Student's t-tests were used to compare Short Form health outcomes survey (SF-12) health outcomes between high and low hs-CRP, and presurgical and postsurgical visits.

RESULTS

Mean ± standard deviation (SD) baseline and 1-year hs-CRP values for the low hs-CRP group were 0.55 ± 0.23 mg/l and 1.22 ± 1.32 mg/l, respectively (n = 15; p = 0.051) and for the high hs-CRP group were 7.86 ± 5.98 mg/l and 14.11 ± 38.9 mg/l, respectively (n = 13; p = 0.54). Lymphocytes were present in 10 synovium and one bone sample (all but one from high hs-CRP group). Interleukin (IL)-5 and IL-10 were significantly correlated with hs-CRP (p = 0.0137 and p = 0.0029, respectively). The low hs-CRP group exhibited significant improvement in the physical component of SF-12 at 6 and 12 months compared with baseline, whereas the high hs-CRP group exhibited significant improvement only at 6 months. Body mass index (BMI) had a significant positive correlation with presurgical hs-CRP.

CONCLUSIONS

The results of this study provide support for inflammatory mechanisms contributing to the OA progression, with hs-CRP being a possible predictive variable, combined with BMI and other comorbidities, of post-TKA function.

Expression levels of matrix metalloproteinase (MMP)-9 and its specific inhibitor TIMP-1, in septic and aseptic arthritis of the knee

PURPOSE

In cases of septic knee arthritis, there is excess of matrix metalloproteinases (MMPs) over tissue inhibitors of metalloproteinases (TIMPs), due to enhanced expression and activation that are induced by bacteria in comparison with rheumatic or degenerative arthritis. The aim of this study was to explore the expression levels of synovial gelatinase MMP-9 and its specific inhibitor TIMP-1 in septic and aseptic arthritis and their potential use as additional aids to clinical investigation.

METHODS

Gelatin zymography and western blot analysis were applied in effusions from knees of the patients with septic (SA-10 patients), rheumatic (RA-10 patients) and osteoarthritis (OA-10 patients).

RESULTS

Zymographic analysis revealed that all samples contained latent MMP-2 activity, albeit activated MMP-2 appeared in more of the septic than aseptic effusions. MMP-9 was not detected in osteoarthritic synovial fluid samples. Only trace amounts of MMP-9 activity were detected in 4 of 10 patients with RA, whereas higher MMP-9 levels were evident in all samples from SA (P = 0.0241). In immunoblotting assays, samples from SA showed significantly higher levels of MMP-9 compared with samples from RA (P = 0.0052), confirming zymographic results. Although no significant difference in TIMP-1 levels was observed, the estimated MMP-9/TIMP-1 ratio of septic effusions was significantly higher compared with aseptic ones (P = 0.0029).

CONCLUSIONS

The data presented suggest enhanced expression and activation of MMP-9 in septic native knee arthritis compared with aseptic. The presence of high levels of MMP-9 with concomitantly increased MMP-9/TIMP-1 ratio and activated gelatinases in effusions, independent of neutrophilic counts, may be indicative for infection.

Effects of adenovirus-mediated bFGF, IL-1Ra and IGF-1 gene transfer on human osteoarthritic chondrocytes and osteoarthritis in rabbits

The study investigated the effects of adenovirus-mediated gene transfection of basic fibroblast growth factor (bFGF), bFGF combined with interleukin-1 receptor antagonist protein (IL-Ra) and/or insulin-like growth factor-1 (IGF-1) both in human osteoarthritis (OA) chondrocytes and rabbits OA model. Human OA chondrocytes were delivered by adenovirus-mediated bFGF, IL-Ra and IGF-1 vectors, respectively. Chondrocyte proliferation, glycosaminoglycan (GAG) content, expression of type II collagen, ADAMTS-5, MMP-13, MMP-3 and TIMP-1 were determined. Rabbit OA model was induced by anterior cruciate ligament transaction (ACLT) in knees. Adenoviral vectors encoding human bFGF, IL-Ra and IGF-1 were injected intraarticularly into the knee joints after ACLT. The effects of adenovirus-mediated gene transfection on rabbit OA were evaluated. In vitro, the transfected genes were expressed in cell supernatant of human OA chondrocytes. AdbFGF group significantly promoted chondrocyte proliferation, and increased GAG and type II collagen synthesis than in the OA group. As two or three genes were transfected in different combinations, there was significant enhancement on the GAG content, type II collagen synthesis, and TIMP-1 levels, while ADAMTS-5, MMP-13, and MMP-3 levels were reduced. In vivo, the transfected genes were expressed in synovial fluid of rabbits. Intraarticular delivery of bFGF enhanced the expression of type II collagen in cartilage and decreased cartilage Mankin score compared with the OA control group (P=0.047; P<0.01, respectively). Multiple-gene transfection in different combinations showed better results than bFGF transfection alone. This study suggests that bFGF gene transfection is effective in treating experimental OA. Multiple gene transfection has better biologic effects on OA.

Analysis of Serum Proteins and Enzymes Level in Human Subjects with Osteoarthritis

The aim of the present study was to assess the serum proteins and enzymes level using polyacrylamide gel electrophoretic (PAGE) profiles in human subjects with osteoarthritis (OA). Forty-one subjects with confirmed OA were selected for the present study. Sera were collected from these individuals and loaded in equal amounts on native and denaturing PAGE separately. Software analysis of these profiles was done using Scion Imaging (Beta release-4, Scion Corporation) and GelPro (Media Cybernetics, USA) programs. To visualize esterases (Est) and lactate dehydrogenase (LDH) isoenzymes in the sera of these patients substrate specific staining was performed. Differences in the values of control and OA subjects were tested statistically. Software analysis of native-PAGE profiles revealed the presence of nineteen peptides in control and twenty one in OA subjects respectively. Two extra peptides were present in the β-globulins region of OA subjects. Significant decline from 42.77% to 34.72% in albumin levels (hypoalbuminemia) was observed in OA subjects with total albumin to globulin ratio 0.58. In SDS-PAGE, the difference in control and OA subjects was observed among eight peptides with molecular weight 25, 22 and 20 kDa (absent in OA) and five novel peptides 270, 125, 30, 21.36 and 18.4 kDa (absent in controls), while albumin retains the major activity. For enzymes, Est follow a relative order, BchEst (42.86%)> ArylEst (16.24%)>AchEst (6.85%) in OA subjects with the expression of a new BchEst isoform in 4.78% and two isoforms of ArylEst at 2.13 and 1.61% concentrations respectively. Significantly declined albumin esterase-like activity (AlbEst) was observed (34%) (P<0.05) in diseased subjects compared with controls (47%). Significant increase in LDH-5 and decline in LDH-1 and -2 isoenzymes were also observed in the sera of OA subjects. However, the overall rank of LDH isoenzymes was similar in control and OA subjects. Our results demonstrate noticeable differences in the sera PAGE profiles and enzymes activity in control and OA subjects and provide evidence to select serum for its use in the search for suitable biochemical markers in osteoarthritis.

Diagnostic Modalities for Diseased Articular Cartilage-From Defect to Degeneration: A Review

The progression of cartilage matrix damage to generalized degeneration is associated with specific pathophysiological and clinical aspects. Reliable detection of stage-related characteristics of cartilage disease serves both a therapeutic and prognostic goal. Over the past years, several (pre)clinical diagnostic modalities for cartilage pathologies have been advocated. Each modality focuses on different aspects of the disease. Early diagnosis, before irreversible damage has occurred, opens up the possibility for better treatment and improves the patients' prognosis. This article gives an overview of the diagnostic modalities available for monitoring cartilage pathology and focuses on reliability, clinical value, current status, and possible applications.

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

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

Determination of MMP-2 and -9 activities in synovial fluid of horses with osteoarthritic and arthritic joint diseases using gelatin zymography and immunocapture activity assays

REASON FOR PERFORMING STUDY

Matrix metalloproteinases (MMPs)-2 and -9 activities have been found elevated in synovial fluid from various joint diseases in man. However, in the horse few data are available.

OBJECTIVES

To explore the clinical significance of MMP-2 and -9 activities in synovial fluid of horses with different forms of joint diseases.

METHODS

Gelatin zymography and MMP-2 and -9 immunocapture activity assays were applied on synovial fluids from control joints and joints with aseptic joint disease (AJD) and septic arthritis (SA). Additionally, MMP-2 and -9 activities were measured in samples from SA to monitor the disease process.

RESULTS

Zymographic analysis revealed that samples from AJD and SA contained significantly increased latent MMP-2 activity compared to controls. Samples from SA showed significantly increased monomeric latent MMP-9 activity compared with all other affected joints and controls. Trace amounts of MMP-9 activity, due to the active and dimer form, were detected in samples from SA; however, these bands were absent in samples from AJD and controls. Using immunocapture activity assays, MMP-2 and -9 activities were found to be significantly elevated in joints from SA compared to controls and AJD samples. MMP-2 activity in samples from AJD was significantly increased compared to controls. Both MMP activities decreased in the joints from SA in the course of successful therapy.

CONCLUSIONS

Data from zymographic analysis confirmed that MMP-2 and -9 were elevated in equine joint diseases. Immunocapture activity assays have been shown to be suitable for the quantitative determination of MMP-2 and -9 activities in synovial fluid of horses. Both MMP-2 and -9 activities seem to be useful to indicate SA, and MMP-2 activity might be a suitable marker for AJD.

POTENTIAL RELEVANCE

These findings encourage the potential use of MMP-2 and -9 as additional aids to clinical investigation. Further work is required to validate the clinical significance of MMP activities in the progress of different joint diseases in horses.

Use of a portable thermal imaging unit as a rapid, quantitative method of evaluating inflammation and experimental arthritis

INTRODUCTION

Thermal imaging has been utilized, both preclinically and clinically, as a tool for assessing inflammation and arthritis. However, previous studies have employed large, relatively immobile devises to obtain the thermal signature of the tissue of interest. The present study describes the characterization of a hand-held thermal imaging device in a preclinical model of general inflammation and a model of rheumatoid arthritis (RA).

METHODS

A hand-held ThermoView Ti30 portable thermal imager was utilized to detect the temporal changes in thermal signatures in rat model of carrageenan-induced paw edema (CFE) and a model of collagen-induced arthritis (CIA). In both in vivo models, the kinetics of the thermal changes were correlated to footpad swelling. In addition, the CFE model was utilized to examine the ability of this technology to delineate pharmacodynamic changes in thermal signature in response to the non-steroidal anti-inflammatory drug indomethacin (10 mg/kg; p.o.).

RESULTS

Thermal analysis of rat paws in the CFE model demonstrated a significant increase in the mean temperature difference between the inflamed and contralateral control paw by two hours post-carrageenan (8.3 +/-0.5 degrees F). Indomethacin significantly decreased the mean temperature difference in treated animals as compared to vehicle. In the rat CIA model, increases in footpad temperature, as determined by thermal imaging, were significantly elevated by Day 11 and remained elevated throughout the duration of the 28 day protocol. Thermal changes were also found to precede increases in footpad edema (swelling).

DISCUSSION

The results of this study demonstrate that the hand-held thermal imaging technology represents a rapid, highly-reproducible method by which to quantitate the degree of inflammation in rat models of general inflammation and rheumatoid arthritis. The ability to detect pharmacodynamic responses in paw temperature suggests that this technology may be a useful tool for the development of pharmacologic interventions for the treatment inflammation-related pathologies.

Primer: the practical use of biological markers of rheumatic and systemic inflammatory diseases

The assessment of systemic inflammation by means of laboratory tests often complements the results of medical examination. Traditionally, the erythrocyte sedimentation rate and leukocytosis with left shift are diagnostic markers for inflammatory and infectious diseases. The levels of acute-phase proteins--especially C-reactive protein--are used to assess both the presence of inflammation and any response to treatment. The determination of C-reactive protein levels may be advised in three types of pathological situation: infection, acute or chronic inflammation, and evaluation of metabolic risk. Procalcitonin is useful as a marker of sepsis and severe infection. The concentration of serum amyloid A predicts the chances of survival of patients with secondary (AA) amyloidosis. Ferritin and its glycosylated form are of interest in the study of specific diseases such as adult-onset Still's disease. Markers of cartilage and bone turnover are complementary to these markers of inflammation. Although cytokine serum levels are transiently crucial to the generation of inflammation, their usefulness in the clinic is still under investigation. Serum concentrations of cytokine inhibitors or soluble cytokine receptors, as well as the clinical response of patients to treatment with cytokine antagonists, might generate important information for monitoring autoinflammatory diseases.

Middle ear admittance and hearing abnormalities in individuals with osteoarthritis

In osteoarthritis, the joint cartilage breaks down. Cartilage exists within the incudomalleolar and incudostapedial joints. In addition, the cartilage-covered base of the stapes footplate is bound to the cartilage-covered rim of the oval window by the annular ligament. Thus, higher prevalence of middle ear abnormalities and hearing loss can be expected in osteoarthritis due to degeneration of the cartilage and the subsequent abnormal repair response. In this study, tympanometric and audiometric data were obtained from 15 individuals diagnosed with osteoarthritis and 15 gender- and age-matched individuals without the diagnosis of arthritis. Results showed a significantly higher prevalence of middle ear abnormalities and hearing loss in ears with arthritis when compared to the control group. Interestingly, osteoarthritis and hearing loss are considered among the top chronic health concerns in older individuals although the connection between these two conditions has not been previously reported.