Early osteoarthritis and microdialysis: a novel in vivo approach for measurements of biochemical markers in the perisynovium and intraarticularly

Microdialysis to Quantify Inflammatory Cytokines in the Glenohumeral Joint: A Brief Methods Report

Microdialysis quantifies in vivo soft-tissue biochemical concentrations via passive diffusion of interstitial molecules through a porous membrane into a dialysate. The purpose of this pilot study was to evaluate a technique to measure inflammatory cytokines associated with rotator cuff tendinopathy by inserting a microdialysis catheter into the posterior glenohumeral joint. The technique was tested in a convenience sample of six pain-free, able-bodied veterans. Complete dialysate samples were collected in two participants. Two participants' sample volumes were smaller than what was required for analysis (30 μl) and thus were diluted. Catheter failures in two participants prevented collection altogether. Three cytokine concentrations were quantified: interleukin-1 receptor antagonist, interleukin 8, and regulated on activation, normal T-cell expressed and secreted. Microdialysis is not recommended for use in the glenohumeral joint, yet quantification of glenohumeral joint cytokines could yield valuable information to better understand pathophysiology of the joint and its surrounding tissues. Another technique, such as joint lavage, may be a more attractive alternative to overcome the limitations of microdialysis in the glenohumeral joint.

Intra-articular zoledronic acid in a rat osteoarthritis model: significant reduced synovitis may indicate chondroprotective effect

PURPOSE

The aim of this experimental study was to evaluate the effect of intra-articular application of zoledronic acid (ZA) on joint cartilage and synovial tissue following induction of knee osteoarthritis (OA) in a rat model.

METHODS

An OA model was created by anterior cruciate ligament transection (ACLT) in the right knees of 48 adult Wistar albino rats. The rats were randomized into a study and control groups, each including 24 rats, and 10 μg of ZA was injected in 0.1 ml of sterile saline to 24 animals in the study group on the first day to operation and was repeated weekly until the rats were killed. The same volume of sterile saline was injected with the same schedule to the control group. Eight rats from both the study and control groups were killed, each time, on the 4th day, the 3rd week, and the 6th week after the operation. The groups were compared based on the histological scores of synovitis and cartilage destruction and the evaluation of serum markers.

RESULTS

Histological score indicates progression of synovitis was significantly less in the study group (p = 0.047). There was significant increase in the mean Mankin cartilage damage score in the control group (p = 0.021), while no significant change was found in the study group. When the two groups were compared over time, no statistically significant difference was detected in total histological scores, although there was a 47 % less incidence of cartilage tissue damage in the study group and better cartilage structure and tide mark integrity scores were also detected in the study group (p = 0.017 and p = 0.021, respectively).

CONCLUSION

Intra- articular zoledronic acid may suppress synovial inflammation. Furthermore, Zoledronic Acid does not reduce cartilage degeneration in early osteoarthritis models, but may provide some chondroprotective effect in ACLT- induced knee osteoarthritis model in rats.

Efficacy of strength and aerobic exercise on patient-reported outcomes and structural changes in patients with knee osteoarthritis: study protocol for a randomized controlled trial

BACKGROUND

Despite an extensive literature on treatment interventions for patients with knee osteoarthritis, studies comparing the efficacy of different exercise interventions and living the life as usual on quality of life, cartilage quality and cost-effectiveness are lacking. The aim of the present study is to compare the efficacy of two different exercise programs compared to a control group in individuals with established radiographic and symptomatic knee osteoarthritis on self-reported knee-related quality of life, knee pain, physical function, and cartilage quality.

METHODS/DESIGN

A three-armed randomized controlled trial involving two exercise interventions and a control group of individuals doing as they usually do is described. The patients will have mild to moderate radiographic osteoarthritis according to the Kellgren and Lawrence classification (grade 2-3), and fulfill the American College of Rheumatology clinical criteria, be aged between 45 and 65 years, and have no other serious physical or mental illnesses. The patients will be randomly allocated to a strength exercise group; a cycling group, or a control group. The primary outcome is the Knee injury and Osteoarthritis Outcome Score knee-related quality of life subscale. Secondary outcomes include all five Knee Injury and Osteoarthritis Outcome Score subscales, morphological evaluation of cartilage including focal thickness, subchondral bone marrow edema, proteoglycan content and collagen degradation (measured using magnetic resonance imaging clinical sequences, T2 mapping and T1ρ), specific serum biomarkers, isokinetic muscle strength, maximal oxygen uptake, quality of life (EuroQol 5D), and self-efficacy (Arthritis Self-Efficacy Scale). A sample size calculation on the primary outcome showed that 207 individuals, 69 in each group, is needed to detect a clinically relevant difference of 10 points with 80% power and a significance level of 5%. Assessments will be conducted at baseline, 14 weeks, 1 year and 2 years post-randomization. The interventions will be a 14 weeks exercise program.

DISCUSSION

Although exercise therapy has been found to be effective in knee osteoarthritis, the knowledge of the underlying mechanisms for why exercise works is lacking. This study will contribute with knowledge on the efficacy of strength exercise versus cycling on patient-reported outcomes, cartilage quality and cost-effectiveness.

TRIAL REGISTRATION

Clinicaltrial.gov Identifier: NCT01682980.

Scanty integration of osteochondral allografts cryopreserved at low temperatures with dimethyl sulfoxide

PURPOSE

To compare the integration of osteochondral allografts cryopreserved at different temperatures and different concentrations of dimethyl sulfoxide in an in vivo sheep animal model.

METHODS

Thirty-six adult sheep were randomly allocated to 6 groups of allograft osteochondral transplantation. Six osteochondral cylinders were stored for 6 weeks at -80°C; 6 at -80°C with 10% dimethyl sulfoxide (DMSO); 6 at -80°C with 10% DMSO for 90 min; 6 at -186°C; 6 at -186°C with 10% DMSO; 6 at -186°C for 90 min. After transplantation, all animals were euthanized at 6 months. Harvested specimens underwent gross morphologic and histologic evaluation.

RESULTS

We found no statistically significant differences when comparing the gross cartilage morphology and histopathologic scores of each group. The Mankin and OARSI scores and the modified Wakitani and OARSI scores showed a good correlation grade. The Mankin and modified Wakitani scores showed a fair correlation grade.

CONCLUSION

The cryopreservation protocols adopted in the present study provided scanty integration in an in vivo sheep model of osteochondral allograft transplantation. Therefore, their use in the clinical practice is discouraged.

Osteoarthritis year 2010 in review: biochemical markers

At the 2010 Osteoarthritis Research Society International (OARSI) congress in Brussels I was asked to present on "Biochemical Markers" in the "Year in Review" session. This provided an opportunity to summarize ongoing work and consensus building in the osteoarthritis research community related to osteoarthritis biomarkers, and second, and an opportunity to briefly overview a subset of studies from the previous 12 months related to soluble biomarkers that provided novel insights in the field. This review therefore briefly summarizes the progress in 2010 of the OARSI OA Biomarkers Global Initiative and the OARSI FDA Biomarkers Working Group, and provides a summary of selected osteoarthritis biomarker studies reported over the previous 12 months based on a review of articles from seven musculoskeletal journals and a PubMed search using the terms biomarkers and osteoarthritis.

Exercise increases interleukin-10 levels both intraarticularly and peri-synovially in patients with knee osteoarthritis: a randomized controlled trial

Introduction

The microdialysis method was applied to the human knee joint with osteoarthritis (OA) in order to reveal changes in biochemical markers of cartilage and inflammation, intraarticularly and in the synovium, in response to a single bout of mechanical joint loading.

Methods

Thirty-one female subjects with OA of the knee were randomized to non-exercise (NEx) or exercise (Ex) groups. Following acute resistance exercise (25 sets of 10 repetitions at 60% of 1 Repetition Maximum) or none (NEx), peripheral nerve blocks just below the inguinal ligament were applied and two microdialysis catheters were positioned in two different compartments, intraarticularly and peri-synovially. The microdialysis catheters were perfused at a slow rate (2 μl/minute) with a solution of Ringer-acetate and radioactively labelled glucose allowing for determination of relative recovery (RR) and calculation of interstitial concentrations of inflammatory and cartilage biomarkers over a three-hour period.

Results

A significant increase of Interleukin (IL) -10 was discovered in both positions of the knee in the Ex group over the three hours post exercise, whereas IL-10 remained stationary over time in the NEx group. IL-6 and IL-8 displayed significant increases over time regardless of group and position of the catheter. Cartilage oligomeric matrix protein (COMP) decreased intraarticularly in the post exercise period in the Ex group compared to the NEx group.

Conclusions

Exercise caused an increase in both intraarticular and peri-synovial concentrations of IL-10 in a group of human females with knee OA. This suggests a positive effect of exercise on a chondroprotective anti-inflammatory cytokine response in patients with knee OA and might contribute to explaining the beneficial effect that exercise has on OA.

Trial registration

NCT01090375.