Synovial cytokine expression in ankle osteoarthritis depends on age and stage

Tizoxanide as a novel theraputic candidate for osteoarthritis

Osteoarthritis (OA) is a frequently seen degenerative joint disease in the elderly. Its pathogenesis is highly related to the local inflammatory reaction and autophagy. Tizoxanide (Tiz), the main active metabolite of nitazoxanide, has proved its anti-inflammatory properties in several diseases. However, the exact role of Tiz in OA remains to explore. In this study, we investigated the anti-arthritic effects and the underlying molecular mechanisms of Tiz on rat OA. The results showed that Tiz could attenuate the IL-1β-induced inflammatory disorders, cartilage matrix damage and autophagy reduction in rat chondrocytes. Moreover, employment of autophagy inhibitor 3-methyladenine (3-MA) could antagonize the protective effects of Tiz in IL-1β-treated rat chondrocytes. Additionally, Tiz also inhibited the IL-1β-induced PI3K/AKT/mTOR and P38/JNK phosphorylation in chondrocytes. In vivo, intra-articular injection of Tiz could significantly alleviate the progression of cartilage damage in rat OA model. Briefly, our study demonstrated the therapeutic potential of Tiz in OA, suggesting that Tiz administration might serve as a promising strategy in OA therapy.

RIP1 Perturbation Induces Chondrocyte Necroptosis and Promotes Osteoarthritis Pathogenesis via Targeting BMP7

Osteoarthritis (OA) is a highly prevalent and debilitating joint disorder that characterized by progressive destruction of articular cartilage. There is no effective disease-modifying therapy for the condition due to limited understanding of the molecular mechanisms on cartilage maintenance and destruction. Receptor-interacting protein kinase 1 (RIP1)-mediated necroptosis plays a vital role in various diseases, but the involvement of RIP1 in OA pathogenesis remains largely unknown. Here we show that typical necrotic cell morphology is observed within human OA cartilage samples in situ, and that RIP1 is significantly upregulated in cartilage from both OA patients and experimental OA rat models. Intra-articular RIP1 overexpression is sufficient to induce structural and functional defects of cartilage in rats, highlighting the crucial role of RIP1 during OA onset and progression by mediating chondrocyte necroptosis and disrupting extracellular matrix (ECM) metabolism homeostasis. Inhibition of RIP1 activity by its inhibitor necrostatin-1 protects the rats from trauma-induced cartilage degradation as well as limb pain. More importantly, we identify bone morphogenetic protein 7 (BMP7) as a novel downstream target that mediates RIP1-induced chondrocyte necroptosis and OA manifestations, thereby representing a non-canonical regulation mode of necroptosis. Our study supports a model whereby the activation of RIP1-BMP7 functional axis promotes chondrocyte necroptosis and subsequent OA pathogenesis, thus providing a new therapeutic target for OA.

Enhanced BMP-2/BMP-4 ratio in patients with peripheral spondyloarthritis and in cytokine- and stretch-stimulated mouse chondrocytes

Background

Excessive bone formation in the entheses is one of the features of peripheral spondyloarthritis (SpA). Complex pathological mechanisms connecting inflammation, mechanical stress, and ossification are probably involved. We focused on bone morphogenetic protein (BMP)-2, -4, and -7 as possible mediators of this process.

Methods

BMP-2, -4, and -7 concentration was measured by ELISA in synovial fluids (SFs) of SpA (n = 56) and osteoarthritic (n = 21) patients. Mouse organotypic ankle cultures were challenged by a pro-inflammatory cocktail. Mouse primary chondrocytes, osteoblasts, or tenocytes were treated with TNF-α, interleukin (IL)-17, or IL-22 and/or subjected to cyclic stretch, or with recombinant BMP-2 or -4.

Results

In SpA SFs, if BMP-7 was barely detectable, BMP-2 concentration was higher and BMP-4 was lower than in osteoarthritic samples, so that BMP-2/BMP-4 ratio augmented 6.5 folds (p < 0.001). In SpA patients, TNF-α, IL-6, and IL-17 levels correlated this ratio (n = 21). Bmp-2/Bmp-4 ratio was similarly enhanced by cytokine treatment in explant and cell cultures, at mRNA level. In particular, simultaneous application of TNF-α and cyclical stretch induced a 30-fold increase of the Bmp-2/Bmp-4 ratio in chondrocytes (p = 0.027). Blockade of prostaglandin E₂ and IL-6 production had almost no effect on the stretch-induced regulation of Bmp-2 or -4. Osteoinductive effects of BMP-4, and to a lesser extend BMP-2, were identified on cultured chondrocytes and tenocytes.

Conclusions

Our results first settle that BMP factors are locally deregulated in the SpA joint. An unexpected decrease in BMP-4 could be associated to an increase in BMP-2, possibly in response to mechanical and/or cytokine stimulations.

The effect of a heel-unloading orthosis in short-term treatment of calcaneus fractures on physical function, quality of life and return to work - study protocol for a randomized controlled trial

BACKGROUND

There are no standardized therapy guidelines for rehabilitation of calcaneus fractures. While there is consensus on non or partial weight-bearing, the use of supporting devices such as specific foot ankle orthosis is still a matter of debate. Recently, a heel-unloading orthosis ("Settner shoe") was introduced for aftercare of these fractures, allowing walking by shifting the load to the middle-foot and forefoot. This orthosis enables early mobilization of patients suffering from either one-sided or two-sided fractures. The Settner shoe can be applied in non-operative therapy and after surgery. Specifically in calcaneus fractures, early regain of physical activity has been highlighted as one of the key factors for quality of life and the ability to return to work. Thus, we hypothesize that mobilization with the Settner shoe results in improved quality of life and greater physical activity within the first 3 months.

METHODS

This is going to be analyzed by a randomized controlled study comparing treatment with and without this specific orthosis. The secondary outcome measure is the time point of return to work in patients aged between 18 and 60 years, with calcaneus fracture. Furthermore, the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, a 3-dimensional gait analysis, and the Euroqol-5 dimension-3 level (EQ-5D-3 L) questionnaire for quality of life are assessed.

DISCUSSION

This is the first trial applying a standardized rehabilitation protocol in patients with calcaneus fractures, aiming to improve the non-operative part of treatment by use of an orthosis.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03572816 . Registered on 27 July 2018.

Validation of Activity Tracking Procedures in Elderly Patients after Operative Treatment of Proximal Femur Fractures

Background

Early postoperative physical activity in elderly patients suffering from proximal femoral fractures may reduce mortality. We hypothesized that activity trackers can reliably and objectively monitor the in-hospital mobilization, correlating with functional independence and quality of life.

Methods

Three different tracker types (Fitbit™ flex, Misfit™ Shine, and Axivity AX3) at three locations (wrist, ankle, and femur) recorded steps and signal vector magnitudes (SVM) in 22 patients. They were 81 ± 8 years old, were equally distributed between the sexes, and had an ASA score of 2.5 ± 0.6. Single protocoled activity events (n = 191) were clinically categorized into 4 levels and correlated with the monitored signals. Additionally, 2 ± 1 and 8 ± 3 days after the operation, the EuroQol-5D and the Barthel-20 index supplemented this data.

Results

All measurements at the wrist (Fitbit, Misfit) resulted in unacceptable accuracy; however, sensitivity and specificity reached around 90% using the Misfit at the ankle. Applying this combination, the correlation between real and measured steps (R² = 0.99) and the category discrimination were statistically significant (p < 0.002). A discriminant analysis featured the calculation of four activity levels based on SVM measurements using the Axivity tracker at the femur. A cluster analysis showed a 100% agreement between the clinically observed and the calculated activity levels. The amount of active minutes or periods and both the EuroQol-5D and the Barthel-20 indices significantly increased between the analyzed time points after the operation. However, only the Barthel-20 was associated with the measured activity levels (p < 0.01).

Conclusion

The Misfit and the Axivity trackers can reliably monitor activity in elderly patients after operative treatment of proximal femur fractures. However, the wear location is decisive. Objectively measured activity correlated with functional independence and quality of life.

Increased cytokine levels and histological changes in cartilage, synovial cells and synovial fluid after malleolar fractures

BACKGROUND

Malleolar fractures are among the most common fractures in the human skeleton with a high risk of later development of post-traumatic osteoarthritis (OA). The acute ankle injury initiates a sequence of events potentially leading to progressive articular surface damage resulting from inflammatory changes in cartilage, synovial tissue and synovial fluid. We hypothesised that in the acute phase of ankle fracture, these changes occur at the same time in the different tissues.

METHODS

Specimens of chondral tissue, synovial tissue and synovial fluid were collected from 16 patients with acute articular ankle fracture (study group). Additional samples were obtained from five male fresh cadavers within 12 hours of death (control group). Chondral tissue was assessed for cellularity, irregularities and chondrocyte disarray. Synovial tissue was assessed for synovitis, proteoglycans and collagen deposition. Synovial fluid was assessed for cytokines IL-2, IL-6, IL-10, IL-17, IFN-γ and TGF-β1.

RESULTS

Chondral tissue showed discontinuity in the tidemark between cartilage and subchondral bone, chondrocyte disarray, increased cellularity (both at the cartilage surface and subchondral bone), articular surface irregularities and increased deposition of proteoglycans and collagen fibres. Synovial tissue showed a statistically significant difference between the study and control groups in the concentration per tissue area of both thin collagen fibres (p=0.0274) and thick collagen fibres (p<0.0001). Cytokine concentrations in synovial fluid samples were significantly higher in ankle fracture tissue compared with controls for IL-2 (p=0.0002), IL-6 (p<0.0001), IL-10 (p=0.002) and IL-17 (p<0.0001). No statistically significant differences were observed for IFN-γ (p=0.06303) and TGF-β1 (p=0.8832).

CONCLUSION

We observed a pattern of simultaneous and interrelated pathological changes in cartilage, subchondral bone, synovial tissue and synovial fluid after acute malleolar fracture. As the observed inflammatory changes could lead to the development of OA, a more thorough knowledge of these early processes could be helpful to find strategies for prevention or delay of this common complication.

Five-Year Outcomes After Treatment for Acute Instability of the Tibiofibular Syndesmosis Using a Suture-Button Fixation System

Background:

Suture-button repair is a widely accepted surgical treatment for acute and isolated ankle syndesmosis injuries. To our knowledge, midterm results have not previously been reported.

Purpose:

To evaluate the clinical, qualitative, and quantitative radiological midterm outcomes of suture-button repair after acute isolated ankle syndesmosis injuries.

Study Design:

Retrospective case series; Level of evidence, 4.

Methods:

Clinical outcomes were measured using the Foot and Ankle Disability Index (FADI) and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Three-tesla magnetic resonance imaging (MRI) was performed bilaterally at the ankle. Besides morphological sequences for evaluation of the syndesmosis and degenerative changes of the ankle using the Ankle Osteoarthritis Scoring System (AOSS), the MR protocol included a coronal 2-dimensional multislice multiecho sequence for quantitative cartilage T2-weighted mapping. Spearman correlations and paired t tests were used for statistical analysis.

Results:

This retrospective study included 19 consecutive patients (mean age, 29.7 ± 11.5 years) with acute isolated syndesmosis injuries treated with a suture-button system between January 2006 and June 2014, with a mean follow-up of 5.1 ± 2.6 years. Postoperatively, the median FADI score was 136 (range, 78-136), and the median AOFAS score was 100 (range, 87-100). Seventeen (89.5%) patients reported to have reached their preinjury level of sports activities. MRIs of 16 patients were obtained and all showed intact anterior and posterior syndesmotic ligaments; however, in most patients, the previously injured syndesmotic ligament was thickened compared with the uninjured ankle. Average width of the anterior (P = .81) and posterior (P = .60) syndesmosis was not significantly different between the ipsilateral (3.2 ± 1.2 and 4.4 ± 0.9 mm) and contralateral ankles (3.0 ± 0.6 and 4.2 ± 0.7 mm). The median AOSS score was 1.5 (range, 0-11) for the ipsilateral ankle and 0 (range, 0-6) for the contralateral ankle. T2 values of articular cartilage did not significantly differ between the involved and the uninjured ankle (P = .68). Five patients needed hardware removal due to persistent skin irritation, and 1 patient suffered from reinstability of the ankle resulting in revision surgery 2 years after the index surgery.

Conclusion:

Suture-button fixation is an excellent treatment for acute and isolated syndesmosis injuries, resulting in stable ankles without early or advanced osteoarthritic changes at midterm follow-up.

Osteoarthritis in Football

Football is currently the most popular sporting activity in the world. Multiple reports have shown that a high incidence of osteoarthritis is found in football players. Evidence clearly shows that traumatic injury significantly predisposes players for such pathophysiology. Injuries are frequent in amateur as well as professional football players, with knee and ankle accounting for the most severe injuries. Many professional athletes lose playing time due to injuries and many are forced into early retirement. Posttraumatic osteoarthritis is a common finding among ex-football players with numbers well above the normal population. Today's surgical techniques are advanced and capable of restoring the joint to a certain extent. However, a restitution ad integrum is reached only in very rare cases. Professional football players that return to play after serious injuries perform their extremely strenuous activity on morphologically compromised joints. Incomplete rehabilitation and pressure to return to play after an injurious event clearly put the athlete at an even higher risk for joint degeneration. Prevention strategies, improved surgical management, strict rehabilitation, as well as future aspects such as early suppression of inflammation, personalized medicine, and predictive genomics DNA profiling are needed to reduce incidence and improve the health perspectives of football players.

Prospective Clinical Trial for Septic Arthritis: Cartilage Degradation and Inflammation Are Associated with Upregulation of Cartilage Metabolites

Background. Intra-articular infections can rapidly lead to osteoarthritic degradation. The aim of this clinical biomarker analysis was to investigate the influence of inflammation on cartilage destruction and metabolism. Methods. Patients with acute joint infections were enrolled in a prospective clinical trial and the cytokine composition of effusions (n = 76) was analyzed. Characteristics of epidemiology and disease severity were correlated with levels of cytokines with known roles in cartilage turnover and degradation. Results. Higher synovial IL-1β concentrations were associated with clinical parameters indicating a higher disease severity (p < 0.03) excluding the incidence of sepsis. Additionally, intra-articular IL-1β levels correlated with inflammatory serum parameters as leucocyte counts (LC) and C-reactive protein concentrations (p < 0.05) but not with age or comorbidity. Both higher LC and synovial IL-1β levels were associated with increased intra-articular collagen type II cleavage products (C2C) indicating cartilage degradation. Joints with preinfectious lesions had higher C2C levels. Intra-articular inflammation led to increased concentrations of typical cartilage metabolites as bFGF, BMP-2, and BMP-7. Infections with Staphylococcus species induced higher IL-1β expression but less cartilage destruction than other bacteria. Conclusion. Articular infections have bacteria-specific implications on cartilage metabolism. Collagen type II cleavage products reliably mark destruction, which is associated with upregulation of typical cartilage turnover cytokines. This trial is registered with DRKS00003536, MISSinG.

Prospective clinical trial of patients who underwent ankle arthroscopy with articular diseases to match clinical and radiological scores with intra-articular cytokines

OBJECTIVE

There is still a lack of reliable data on cytokine concentrations in the ankle and their value for prognosis.

METHODS

In a prospective clinical trial, lavage fluids were collected from 49 patients with an arthroscopy of the ankle. The fluids were investigated by ELISA for cytokine levels. Clinical scores (FFI, AOFAS) were evaluated both pre-operatively and then again 12 months after surgery (n = 43, 88%). Radiological changes were noted with the Kellgren-Lawrence-Score (KLS) and the Ankle Osteoarthritis Scoring System (AOSS). Based on the difference between the pre- and postoperative clinical scores, two groups were defined according to whether they had benefited from the surgical therapy (Δ score ≥ 10) or not (Δ score < 10).

RESULTS

The average clinical scores had improved to a statistically significant extent in the one-year follow-up (p < 0.01). BMP-2 (p = 0.02), IGF-1 (p = 0.04), BMP-7 (p = 0.01) and aggrecan (p = 0.04) showed significant correlations with pre-operative clinical and radiological scores (p = 0.02, p = 0.01, p = 0.01, p = 0.01). Furthermore, BMP-2 (p = 0.01), IGF-1/TPC (p = 0.03) and aggrecan (p = 0.01) correlated with scores after one year (p = 0.02, p = 0.01). High aggrecan concentrations were associated with a low clinical and a high radiological score at both time points, both indicating progress of cartilage degeneration in contrast to BMP-2 or IGF-1. Furthermore, MMP-13 concentrations were significantly higher in the non-benefit group (p = 0.02).

CONCLUSION

BMP-2, IGF-1, aggrecan and MMP-13 seem to be involved in the degenerative process of cartilage in the ankle joint. Additionally, high synovial MMP-13 concentrations indicate a worse clinical outcome.

Association between intraarticular cytokine levels and clinical parameters of osteochondritis dissecans in the ankle

Background

Reliable data about in vivo regulation of cytokines in osteochondritis dissecans (OCD) of the ankle are still missing. Disease-specific regulation patterns were hypothesized.

Methods

28 patients with a mean age of 30.7 ± 14.8 years undergoing an arthroscopy of the ankle because of OCD were prospectively included in a clinical trial. Lavage fluids were analyzed by ELISA for levels of aggrecan, BMP-2, BMP-7, IGF-1, IGF-1R, bFGF, endoglin, MMP-13, and IL-1β. Additionally, clinical parameters and scores (FFI, CFSS, AOFAS) were evaluated and supplemented by the Kellgren Lawrence Score (KLS) for conventional X-rays and the Ankle Osteoarthritis Scoring System (AOSS) for MRI.

Results

Grading of OCD lesions statistically significant increased with age and was higher in case of previously performed operations (p < 0.03). A worse clinical function reflected by low AOFAS and CFSS scores or high FFI was associated with high grading of cartilage damage or OCD (p < 0.03). Similarly, high radiological scores (KLS and AOSS) indicating progress of OA positively correlated with grading of cartilage damage and OCD. The concordance between the MRI and arthroscopic classification was overall moderate (κ = 0.52). Biochemically, only IGF/IGF-1R levels were consistently negatively associated with OCD grading, ICRS score, FFI and KLS (p < 0.05). Correlation data is supported by post hoc statistics.

Conclusions

Radiological and clinical parameters in association with synovial IGF-1/IGF-1R levels indicated an increasing joint degeneration with rising OCD stage.

Trial registration

German Clinical Trials Register DRKS00000365, 11/03/2008.

Early intra-articular complement activation in ankle fractures

Cytokine regulation possibly influences long term outcome following ankle fractures, but little is known about synovial fracture biochemistry. Eight patients with an ankle dislocation fracture were included in a prospective case series and matched with patients suffering from grade 2 osteochondritis dissecans (OCD) of the ankle. All fractures needed external fixation during which joint effusions were collected. Fluid analysis was done by ELISA measuring aggrecan, bFGF, IL-1β, IGF-1, and the complement components C3a, C5a, and C5b-9. The time periods between occurrence of fracture and collection of effusion were only significantly associated with synovial aggrecan and C5b-9 levels (P < 0.001). Furthermore, synovial expressions of both proteins correlated with each other (P < 0.001). Although IL-1β expression was relatively low, intra-articular levels correlated with C5a (P < 0.01) and serological C-reactive protein concentrations 2 days after surgery (P < 0.05). Joint effusions were initially dominated by neutrophils, but the portion of monocytes constantly increased reaching 50% at day 6 after fracture (P < 0.02). Whereas aggrecan and IL-1β concentrations were not different in fracture and OCD patients, bFGF, IGF-1, and all complement components were significantly higher concentrated in ankle joints with fractures (P < 0.01). Complement activation and inflammatory cell infiltration characterize the joint biology following acute ankle fractures.

Biochemical characterization of early osteoarthritis in the ankle

Purpose. Reliable data about in vivo regulation of cytokines in early ankle osteoarthritis (OA) are still missing. Methods. 49 patients with a mean age of 33 ± 14 years undergoing an arthroscopy of the ankle with different stages of chronic OA were prospectively included in a clinical trial. Lavage fluids were analyzed by ELISA. Additionally, clinical parameters and scores (FFI, CFSS, and AOFAS) were evaluated and supplemented by the Kellgren Lawrence Score (KLS) and the ankle osteoarthritis scoring system (AOSS). Results. ICRS grading of cartilage damage, previous operations, and duration of complains were strong indicators for OA progress and showed correlations to age, clinical scores, validated KLS, and AOSS (P < 0.04). Systemic and intraarticular inflammatory parameters were low in all patients. Biochemically, aggrecan and BMP-7 positively indicated OA with statistically significant associations with duration of symptoms, FFI, AOFAS, and KLS (P < 0.04). In contrast, BMP-2 levels showed statistically significant negative correlations to aggrecan or BMP-7 concentrations, which is in line with the negative association with ICRS score and KLS and the positive correlation with FFI (P < 0.03). Conclusions. We were able to identify different key markers of OA in the ankle as aggrecan, BMP-7, and BMP-2, offering starting points for new ways in diagnostics and interventional strategies.