| 1. |
- Chockalingam, P. S., et al.
(författare)
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Elevated aggrecanase activity in a rat model of joint injury is attenuated by an aggrecanase specific inhibitor
- 2011
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 19:3, s. 315-323
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate aggrecanase activity after traumatic knee injury in a rat model by measuring the level of aggrecanase-generated Ala-Arg-Gly-aggrecan (ARG-aggrecan) fragments in synovial fluid, and compare with ARG-aggrecan release into joint fluid following human knee injury. To evaluate the effect of small molecule inhibitors on induced aggrecanase activity in the rat model. Method: An enzyme-linked immunosorbent assay (ELISA) was developed to measure ARG-aggrecan levels in animal and human joint fluids. A rat model of meniscal tear (MT)-induced joint instability was used to assess ARG-aggrecan release into joint fluid and the effects of aggrecanase inhibition. Synovial fluids were also obtained from patients with acute joint injury or osteoarthritis and assayed for ARG-aggrecan. Results: Joint fluids from human patients after knee injury showed significantly enhanced levels of ARG-aggrecan compared to uninjured reference subjects. Similarly, synovial fluid ARG-aggrecan levels increased following surgically-induced joint instability in the rat MT model, which was significantly attenuated by orally dosing the animals with AGG-523, an aggrecanase specific inhibitor. Conclusions: Aggrecanase-generated aggrecan fragments were rapidly released into human and rat joint fluids after injury to the knee and remained elevated over a prolonged period. Our findings in human and preclinical models strengthen the connection between aggrecanase activity in joints and knee injury and disease. The ability of a small molecule aggrecanase inhibitor to reduce the release of aggrecanase-generated aggrecan fragments into rat joints suggests that pharmacologic inhibition of aggrecanase activity in humans may be an effective treatment for slowing cartilage degradation following joint injury. (C) 2010 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.
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| 3. |
- Larsson, Staffan, et al.
(författare)
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An ARGS-aggrecan assay for analysis in blood and synovial fluid.
- 2014
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 22:2, s. 242-249
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Tidskriftsartikel (refereegranskat)abstract
- To validate a modified ligand-binding assay for the detection of aggrecanase generated aggrecan fragments with the ARGS neoepitope in synovial fluid (SF) and blood, and to verify the identity of aggrecan fragments found in blood.
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| 4. |
- Larsson, Staffan, et al.
(författare)
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Association between synovial fluid levels of aggrecan ARGS fragments and radiographic progression in knee osteoarthritis.
- 2010
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Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: INTRODUCTION: Aggrecanase cleavage at the 392Glu-393Ala bond in the interglobular domain (IGD) of aggrecan, releasing N-terminal 393ARGS fragments, is an early key event in arthritis and joint injuries. We determined whether synovial fluid (SF) levels of ARGS-aggrecan distinguish subjects with progressive radiographic knee osteoarthritis (ROA) from those with stable or no ROA. METHODS: We studied 141 subjects who, at examination A, had been given meniscectomies an average of 18 years earlier (range, 15 to 22 years). Seventeen individuals without surgery, and without known injury to the menisci or cruciate ligaments, were used as references. At examinations A and B, with a mean follow-up time of 7.5 years, we obtained SF and standing tibiofemoral and skyline patellofemoral radiographs. SF ARGS-aggrecan was measured with an electrochemiluminescence immunoassay, and we graded radiographs according to the OARSI atlas. The association between SF ARGS levels at examination A and progression of radiographic features of knee OA between examinations A and B was assessed by using logistic regression adjusted for age, gender, body mass index, and time between examinations, and stratified by ROA status at examination A. RESULTS: We found a weak negative association between SF ARGS concentrations and loss of joint space: the likelihood of progression of radiographic joint space narrowing decreased 0.9 times per picomole per milliliter increase in ARGS (odds ratio (OR) 0.89; 95% confidence interval (CI), 0.79 to 0.996). In subjects with and without preexisting ROA at examination A, the association was OR, 0.96; 0.81 to 1.13; and 0.77; 0.62 to 0.95, respectively. Average levels of SF ARGS 18 years after meniscectomy were no different from those of reference subjects and were not correlated to radiographic status at examination A. CONCLUSIONS: In subjects with previous knee meniscectomy but without ROA, levels of SF ARGS-aggrecan were weakly and inversely associated with increased loss of joint space over a period of 7.5 years.
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| 5. |
- Larsson, Staffan, et al.
(författare)
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Biological variation of human aggrecan ARGS neoepitope in synovial fluid and serum in early-stage knee osteoarthritis and after knee injury
- 2022
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Ingår i: Osteoarthritis and Cartilage Open. - : Elsevier BV. - 2665-9131. ; 4:4, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine biological variation of the aggrecanase-generated aggrecan ARGS neoepitope in serum (sARGS) and synovial fluid (sfARGS) within and between patients with osteoarthritis (OA) or anterior cruciate ligament (ACL) injury.DESIGN: Matched samples of serum and synovial fluid were available, as parts of clinical trials, from i) 16 subjects with early-stage OA on 8 occasions over 1 year, and ii) 120 subjects with acute ACL injury with samples available from at least 2 of 6 visits over 5 years. We used an in-house immunoassay to quantify ARGS and one-way ANOVA for statistical analyses.RESULTS: Variability in ARGS was higher in synovial fluid than in serum in both patient groups. Subjects with OA had the lowest variability both within and between patients and showed no variation over time in the degree of variability or in the cross-sectional mean, neither in serum nor in synovial fluid. After ACL injury, the concentration and the variability of ARGS was highest immediately after injury, with a subsequent decline both in concentration and in variability with time. In both patient groups there was a positive correlation between sfARGS and sARGS both within and between individuals (correlation coefficients between 0.16 and 0.20).CONCLUSIONS: The biological variation of ARGS is lower in serum than in synovial fluid, and lower in OA than after ACL injury. Serum ARGS is a measure of the total release of ARGS aggrecan from the whole body and a poor reflection of the release of ARGS aggrecan within the affected joint.
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| 7. |
- Larsson, Staffan, et al.
(författare)
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Serum ARGS-aggrecan in a phase 2 clinical trial targeting osteoarthritis
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Ingår i: Osteoarthritis and Cartilage. - 1063-4584. ; , s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- To monitor serum concentrations of the aggrecan alanine-arginine-glycine-serine (ARGS) neoepitope in a clinical trial of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5 inhibition as disease-modifying therapy of knee osteoarthritis, and to investigate relationships between reduction in ARGS and change in cartilage thickness, knee-related pain and function.DesignROCCELLA trial participants received once-daily oral S201086 75, 150 or 300 mg, or placebo, for 52 weeks. Serum was collected at baseline, 4, 12, 28 and 52 weeks, and 2 weeks post-treatment with ARGS measured by an in-house immunoassay. Change from baseline to week 52 in central medial femorotibial compartment cartilage thickness was measured by magnetic resonance imaging, function and pain by Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) subscores. Associations between cumulative change in ARGS and change in cartilage thickness or WOMAC subscores were evaluated by linear regression.ResultsS201086 reduced serum levels of ARGS in a dose-dependent manner throughout the treatment period. Maximal reduction was at 4 weeks with a 58.5% [95% CI 60.8%, 56.2%] reduction of ARGS compared to baseline for 300 mg S201086. Two weeks post-treatment, ARGS concentrations rebounded with a dose-dependent overshoot compared to baseline levels. Cumulative change of ARGS concentration from baseline to week 52 had no effect on change in cartilage thickness (slope −0.8×10−6 [−2.9×10−6, 1.3×10−6]) or change in WOMAC pain and function (slopes −30×10−6 [−64×10−6, 5.2×10−6] and −97×10−6 [−214×10−6, 20×10−6], respectively) at week 52.ConclusionSystemic inhibition of ADAMTS-5 resulted in markedly reduced serum ARGS, but change in serum ARGS concentrations showed no association with the progression of cartilage thinning, or patient reported pain and function.
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| 8. |
- Larsson, Staffan, et al.
(författare)
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Synovial fluid level of aggrecan ARGS fragments is a more sensitive marker of joint disease than glycosaminoglycan or aggrecan levels: a cross-sectional study
- 2009
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Ingår i: Arthritis Research and Therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Aggrecanase cleavage at the (392)Glu-(393)Ala bond in the interglobular domain (IGD) of aggrecan, releasing N-terminal (393)ARGS fragments, is an early key event in arthritis and joint injuries. Here, we use a quantitative immunoassay of aggrecan ARGS neoepitope fragments in human synovial fluid to determine if this cleavage-site specific method better identifies joint pathology than previously available less specific aggrecan assays. Methods Synovial fluid (SF) from 26 people with healthy knees (reference) and 269 patients were analyzed in a cross-sectional study. Patient groups were acute inflammatory arthritis, acute knee injury, chronic knee injury and knee osteoarthritis (OA). Aggrecan ARGS fragments were assayed by ELISA using the monoclonal antibody OA-1. Total aggrecan content was analyzed by an ELISA using the monoclonal antibody 1-F21, and sulfated glycosaminoglycan by Alcian blue precipitation. Results Aggrecan ARGS fragment concentrations in all groups differed from the reference group (P < 0.001). The acute inflammatory arthritis group had the highest median level, 177-fold greater than that of the reference group. Median levels (in pmol ARGS/ml SF) were: reference 0.5, acute inflammatory arthritis 88.5, acute knee injury 53.9, chronic knee injury 0.5 and OA 4.6. In contrast, aggrecan and sulfated glycosaminoglycan concentrations varied much less between groups, and only acute inflammatory arthritis and acute knee injury were found to have a two-fold increase in median levels compared to the reference. Conclusions Levels of aggrecan ARGS fragments in human synovial fluid are increased in human arthritis, OA and after knee injury, likely reflecting an enhanced cleavage at the (392)Glu-(393)Ala bond in the IGD by aggrecanase. An assay that specifically quantified these fragments better distinguished samples from joints with pathology than assays monitoring aggrecan or glycosaminoglycan concentrations. The newly developed ARGS fragment assay can be used to monitor aggrecanase activity in human joint disease and experimental models.
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| 9. |
- Larsson, Staffan, et al.
(författare)
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The association between changes in synovial fluid levels of ARGS-aggrecan fragments, progression of radiographic osteoarthritis and self-reported outcomes: a cohort study.
- 2012
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Ingår i: Osteoarthritis and Cartilage. - : Elsevier BV. - 1063-4584. ; 20:5, s. 388-395
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate whether change in concentrations over time of aggrecanase generated ARGS-aggrecan in synovial fluid (SF ARGS) associates with progression of radiographic knee Osteoarthritis (OA) and patient-reported outcome in subjects with previous meniscectomy. METHODS: We studied 141 subjects at two time points after meniscectomy. Time point A was on average 18years after meniscectomy, time point B was on average 7.5years later; 74 subjects had SF available from both examinations. We measured SF ARGS by an electrochemiluminescence immunoassay, graded radiographic features of tibiofemoral or patellofemoral OA according to the Osteoarthritis Research Society International (OARSI) atlas, and scored patient-reported outcomes using the Knee Injury and Osteoarthritis Outcome Score (KOOS). Using logistic regression (adjusted for age, gender, body mass index, time between examinations, and SF ARGS at first examination) we assessed associations between change in SF ARGS between first and second examinations and progression of radiographic OA and KOOS. RESULTS: In subjects with decreasing SF ARGS between examinations, the likelihood of loss of joint space and worsening of KOOS pain between examinations was increased 6- and 4-fold respectively compared to those increasing in SF ARGS (OR 5.72; 95% CI 1.53-21.4 and 3.66; 1.01-13.2, respectively). No significant associations were seen between decreasing SF ARGS and progression of osteophytes (OR 0.88; 0.28-2.78), or for patient-reported outcomes other than KOOS pain. CONCLUSION: Having decreasing levels of SF ARGS over time was associated with an increased risk of loss of joint space and pain worsening, but showed no association with other patient-reported outcomes or osteophyte progression.
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