Association of synovial fluid and urinary C2C-HUSA levels with surgical outcomes post-total knee arthroplasty.

OBJECTIVES: After total knee arthroplasty (TKA), ∼30% of knee osteoarthritis (KOA) patients show little symptomatic improvement. Earlier studies have correlated urinary (u) type 2 collagen C terminal cleavage peptide assay (C2C-HUSA), which detects a fragment of cartilage collagen breakdown, with KOA progression. This study determines whether C2C levels in urine, synovial fluid, or their ratio, are associated with post-surgical outcomes. METHODS: From a large sample of 489 subjects, diagnosed with primary KOA undergoing TKA, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores were collected at baseline (time of surgery) and one-year post-TKA. Baseline urine (u) and synovial fluid (sf) were analysed using the IBEX-C2C-HUSA assay, with higher values indicating higher amounts of cartilage degradation. For urine, results were normalised to creatinine. Furthermore, subjects' changes in WOMAC scores were categorised based on percent reduction in pain or improvement in function, compared to baseline, such that >66.7%, >33.3 to ≤66.7%, and ≤33.3% denoted "strong", "moderate" and "mild/worse" responses, respectively. Associations of individual biofluid C2C-HUSA levels, or their ratio, with change in WOMAC pain and function scores up to one-year post-TKA, or category of change, were analysed by linear, logistic, or cumulative odds models. RESULTS: Higher baseline uC2C-HUSA levels or a lower ratio of baseline sfC2C-HUSA to uC2C-HUSA were associated with improvements in WOMAC pain by linear multivariable modelling [odds ratio -0.40 (95% confidence interval -0.76, -0.05) p = 0.03; 0.36 (0.01, 0.71), p = 0.04, respectively], while sfC2C-HUSA alone was not. However, lower ratios of sfC2C-HUSA to uC2C-HUSA were associated with improvements in WOMAC function [1.37 (0.18, 2.55), p = 0.02], while sfC2C-HUSA and uC2C-HUSA alone were not. Lower ratios of sfC2C-HUSA to uC2C-HUSA were also associated with an increased likelihood of a subject being categorised in a group where TKA was beneficial in both univariable [pain, 0.81 (0.68, 0.96), p = 0.02; function, 0.92 (0.85, 0.99), p = 0.035] and multivariable [pain, 0.81 (0.68, 0.97) p = 0.02; function, 0.92 (0.85, 1.00), p = 0.043] ordinal modelling, while sfC2C-HUSA and uC2C-HUSA alone were not. CONCLUSIONS: Overall, ratios of baseline sfC2C-HUSA to uC2C-HUSA, and baseline uC2C-HUSA, may play an important role in studying post-TKA surgical outcomes.

T-cell responses to versican in ankylosing spondylitis.

The objective of our study was to undertake a systematic analysis of the T-cell response to the proteoglycan versican G1-globular domain (VG1) in ankylosing spondylitis (AS) as immunity to VG1 in mice can induce a pathology closely resembling AS. Peripheral blood lymphocytes from 36 AS patients and 33 healthy controls were incubated with recombinant human VG1 in culture for 6 h. T-cell responses were assessed by FACS analyses using mAb against surface expression of the activation marker CD69 and against the intracellular cytokines interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha. T cells activated by exposure to versican were determined by assessing the percentage of CD4+ or CD8+ T cells that were CD69/cytokine double-positive cells as compared to isotype control staining. In the AS patients, exposure to VG1 resulted in increased expression by CD4+ T cells of IFN-gamma in 55.6% of patients and of TNF-alpha in 52.8% of patients. In the controls, only 36.4% of subjects demonstrated an IFN-gamma response and 36.4% demonstrated a TNF-alpha response (P value 0.148, 0.227, respectively). With respect to CD8+ T-cell responses, versican stimulation enhanced IFN-gamma expression in 44.4% of AS patients and 39.4% of controls, and enhanced TNF-alpha response in 50.0% of AS patients and 39.4% of controls (P value 0.620, 0.327, respectively). Although, there was no statistically significant difference in the magnitude of the IFN-γ or TNF secretion by CD4+ T cells and CD8+ T cells between AS and controls, our results demonstrate an enhanced T-cell response to VG1 in AS.

Repeated intraarticular injections of triamcinolone acetonide alter cartilage matrix metabolism measured by biomarkers in synovial fluid.

Although intraarticular (IA) corticosteroids are frequently used to treat joint disease, the effects of their repeated use on articular cartilage remains controversial. The aim of our study was to determine the effects of a clinically recommended dose of IA triamcinolone acetonide (TA), on synovial fluid (SF) biomarkers of cartilage metabolism. Ten adult horses, free of osteoarthritis (OA) in their radiocarpal joints, were studied. One radiocarpal joint of each horse was randomly chosen for treatment and the contralateral anatomically paired joint acted as the control. Aseptic arthrocentesis was performed weekly on both joints for 13 weeks. The initial results from the first 3 weeks of the experimental period established baseline untreated control marker levels for each joint, each being its own control. On weeks 3, 5, and 7, a sterile suspension of 12 mg of TA was injected into the treated joint and an equivalent volume of sterile saline solution (0.9%) was injected into the control joint. SF was immunoassayed for biomarkers of aggrecan turnover (CS 846 & KS), types I and II collagen cleavage (C1,2C) and type II collagen synthesis (CPII). In treated joints, there was a significant increase in CS 846, KS, C1,2C and CPII epitope concentrations following IA TA injections when compared to baseline levels. There was also a significant increase in C1,2C and CPII epitope concentrations in the contralateral control joints following IA TA injections in the treated joint. Significant differences were observed between treated and control joints for all markers except CPII. These findings indicate that TA alters articular cartilage and collagen metabolism in treated and, interestingly, also in control joints, suggesting a systemic effect of the drug. Though intuitively the observed findings would favor the hypothesis that long-term IA TA treatment changes joint metabolism and this may have detrimental effects; further studies would be necessary to confirm this.

Differences in type II collagen degradation between peripheral and central cartilage of rat stifle joints after cranial cruciate ligament transection.

OBJECTIVE: Type II collagen degradation is thought to be the key process in cartilage degradation during the development of osteoarthritis (OA). In this study, we investigated the kinetics of type II collagen degradation during surgically induced OA. METHODS: Experimental OA was induced in male Wistar rats by transecting the cranial (anterior) cruciate ligament (CCL). Hematoxylin and eosin staining was used to study overall cartilage degradation, while immunostained sections were used to demonstrate denatured type II collagen (Col2-3/4m antibody) and the collagenase cleavage site in type II collagen (Col2-3/ 4Cshort antibody). RESULTS: During the first 3-4 weeks, cartilage destruction, associated with chondrocyte death, proteoglycan depletion, and a marked increase in the collagenase cleavage neoepitope, was mainly located at the margins of the cartilage. From weeks 3-4, the central part of the cartilage showed increased surface fibrillation and apparent chondrocyte death. In these areas, increased denatured type II collagen staining but little cleavage-site staining was present. CONCLUSION: These results indicate that cartilage degradation after CCL transection in the rat consists of 2 phases. An early phase located at the cartilage margins and a late phase located at the central part of the cartilage. In the early phase, collagenase-dependent cartilage damage occurred. During the late phase, the level of type II collagen denaturation increased.

Evidence for altered synthesis of type II collagen in patients with osteoarthritis.

There is evidence to suggest that the synthesis of type II collagen is increased in osteoarthritis (OA). Using an immunoassay, we show that the content of the C-propeptide of type II procollagen (CPII), released extracellularly from the newly synthesized molecule, is directly related to the synthesis of this molecule in healthy and osteoarthritic articular cartilages. In OA cartilage, CPII content is often markedly elevated (mean 7.6-fold), particularly in the mid and deep zones, reaching 29.6% of the content in newborn. Synthesis is also directly related to total collagen II content in OA, suggesting its importance in maintaining collagen content and cartilage structure. The release of CPII from cartilage is correlated directly with cartilage content. However, the increase in CPII in OA cartilage is not reflected in serum, where a significant reduction is observed. Together these studies provide evidence for alterations in procollagen II synthesis in vivo in patients with OA.