Joint capsule mast cells and neuropeptides are increased within four weeks of injury and remain elevated in chronic stages of posttraumatic contractures

Biomechanical outcomes of pharmacological therapies for post-traumatic arthrofibrosis in preclinical animal models: a systematic review and meta-analysis

PURPOSE/AIM OF THE STUDY

There is still no evidence of which drug has the greatest therapeutic potential for post-traumatic arthrofibrosis. The aim of this study is to systematically review the literature for quality evidence and perform a meta-analysis about the pharmacological therapies of post-traumatic arthrofibrosis in preclinical models.

MATERIALS AND METHODS

A comprehensive and systematic search strategy was performed in three databases (MEDLINE, EMBASE and Web of Science) retrieving studies on the effectiveness of pharmacological therapies in the management of post-traumatic arthrofibrosis using preclinical models in terms of biomechanical outcomes. Risk of bias assessment was performed using the SYRCLE's risk of bias tool. A meta-analysis using a random-effects model was conducted if a minimum of three studies reported homogeneous outcomes for drugs with the same action mechanism.

RESULTS

Forty-six studies were included in the systematic review and evaluated for risk of bias. Drugs from 6 different action mechanisms of 21 studies were included in the meta-analysis. Overall, the methodological quality of the studies was poor. Statistically significant overall effect in favor of reducing contracture was present for anti-histamines (Chi2 p = 0.75, I2 = 0%; SMD (Standardized Mean Difference) = -1.30, 95%CI: -1.64 to -0.95, p < 0.00001) and NSAIDs (Chi2 p = 0.01, I2 = 63%; SMD= -0.93, 95%CI: -1.58 to -0.28, p = 0.005).

CONCLUSIONS

Anti-histamines, particularly ketotifen, have the strongest evidence of efficacy for prevention of post-traumatic arthrofibrosis. Some studies suggest a potential role for NSAIDs, particularly celecoxib, although heterogeneity among the included studies is significant.

Profibrotic behavior of fibroblasts derived from patients that develop posttraumatic shoulder stiffness

Background and Aims

Arthrofibrosis is a severe scarring condition characterized by joint stiffness and pain. Fundamental to developing arthrofibrotic scars is the accelerated production of procollagen I, a precursor of collagen I molecules that form fibrotic deposits in affected joints. The procollagen I production mechanism comprises numerous elements, including enzymes, protein chaperones, and growth factors. This study aimed to elucidate the differences in the production of vital elements of this mechanism in surgical patients who developed significant posttraumatic arthrofibrosis and those who did not.

Methods

We studied a group of patients who underwent shoulder arthroscopic repair of the rotator cuff. Utilizing fibroblasts isolated from the patients' rotator intervals, we analyzed their responses to profibrotic stimulation with transforming growth factor β1 (TGFβ1). We compared TGFβ1-dependent changes in the production of procollagen I. We studied auxiliary proteins, prolyl 4-hydroxylase (P4H), and heat shock protein 47 (HSP47), that control procollagen stability and folding. A group of other proteins involved in excessive scar formation, including connective tissue growth factor (CTGF), α smooth muscle actin (αSMA), and fibronectin, was also analyzed.

Results

We observed robust TGFβ1-dependent increases in the production of CTGF, HSP47, αSMA, procollagen I, and fibronectin in fibroblasts from both groups of patients. In contrast, TGFβ1-dependent P4H production increased only in the stiff-shoulder-derived fibroblasts.

Conclusion

Results suggest P4H may serve as an element of a mechanism that modulates the fibrotic response after rotator cuff injury.

Immune cell populations differ in patients undergoing revision total knee arthroplasty for arthrofibrosis

Arthrofibrosis following total knee arthroplasty (TKA) is a debilitating condition typically diagnosed based on clinical findings. To gain insight into the histopathologic immune cell microenvironment of arthrofibrosis, we assessed the extent of tissue fibrosis and quantified immune cell populations in specific tissue regions of the posterior capsule. We investigated specimens from three prospectively-collected, matched cohorts, grouped as patients receiving a primary TKA for osteoarthritis, revision TKA for arthrofibrosis, and revision TKA for non-arthrofibrotic, non-infectious reasons. Specimens were evaluated using hematoxylin and eosin staining, picrosirius red staining, immunofluorescence, and immunohistochemistry with Aperio®-based digital image analysis. Increased collagen deposition and increased number of α-SMA/ACTA2 expressing myofibroblasts were present in the arthrofibrosis group compared to the two non-arthrofibrotic groups. CD163 + macrophages were the most abundant immune cell type in any capsular sample with specific enrichment in the synovial tissue. CD163 + macrophages were significantly decreased in the fibrotic tissue region of arthrofibrosis patients compared to the patients with primary TKA, and significantly increased in adipose tissue region of arthrofibrotic specimens compared to non-arthrofibrotic specimens. Synovial CD117 + mast cells were significantly decreased in arthrofibrotic adipose tissue. Together, these findings inform diagnostic and targeted therapeutic strategies by providing insight into the underlying pathogenetic mechanisms of arthrofibrosis.

Effects of Different Static Progressive Stretching Durations on Range of Motion, Myofibroblasts, and Collagen in a Posttraumatic Knee Contracture Rat Model

OBJECTIVE

The purpose of this study was to investigate the effects of different durations of static progressive stretching (SPS) on posttraumatic knee contracture in rats, including range of motion (ROM), gait analysis, myofibroblast proliferation, and collagen regulation.

METHODS

The posttraumatic knee contracture model was established, and male Wistar rats were randomly divided into the 20-minute SPS treatment, 30-minute SPS treatment (S30), 40-minute SPS treatment, untreated, immobilization, and control groups. At Week 1, 2, and 4 of treatment intervention, joint ROM and gait were measured and compared. Knee joint samples stained with hematoxylin and eosin and Masson trichrome were used to observe alterations in pathological structures. Collagen density and cell numbers in the posterior joint capsule were used to assess joint capsule fibrosis and inflammation. Immunohistochemistry was used to detect type I collagen and α-smooth muscle actin expression.

RESULTS

The S30 group improved the most; ROM, stance, mean intensity, print area, and stride length were 115 (SD = 5) degrees, 0.423 (SD = 0.074) seconds, 156.020 (SD = 7.952), 2.116 (SD = 0.078) cm2, and 11.758 (SD = 0.548) cm, respectively. The numbers of myofibroblasts, fibroblasts, and inflammatory cells decreased, and collagen proliferation was significantly suppressed in the S30 group compared with the other groups.

CONCLUSION

S30 significantly improved posttraumatic knee contracture in rats, with reduced type I collagen and α-smooth muscle actin expression, decreased the numbers of myofibroblasts and inflammatory cells, suppressed fibrotic and inflammatory changes in the joint capsule, and increased joint mobility. This study provided basic evidence for an optimal standard-of-care treatment approach for posttraumatic knee joint contracture in rats, which may have significance for humans.

An in vivo rabbit joint injury model to measure trauma-induced coagulopathy and the effect of timing of administration of ketotifen fumarate on posttraumatic joint contracture

Objectives:

Using a rabbit in vivo joint injury model, the primary objective of the study was to determine if a relationship exists between earlier time to initiation of ketotifen fumarate (KF) treatment and posttraumatic joint contracture (PTJC) reduction. The secondary objective was to determine if a coagulation response could be detected with serial thrombelastography (TEG) analysis following acute trauma in this model.

Methods:

PTJC of the knee were created in 25 skeletally mature, New Zealand White rabbits. Five groups of 5 animals were studied: a control group that received twice daily subcutaneous injections of normal saline and 4 treatment groups that received twice daily subcutaneous injections of KF (0.5 mg/kg) starting immediately, 1-, 2-, and 4-weeks post-injury. After 8 weeks of immobilization, flexion contractures were measured biomechanically. Serial TEG analysis was performed on the control group animals pre-injury and weekly post-injury.

Results:

The average joint contracture in the Control Group (43.1° ± 16.2°) was higher than all KF treatment groups; however, the differences were not statistically significant. The average joint contracture was lowest in the 2-week post-injury treatment group (29.4° ± 12.1°), although not statistically significant compared to the other treatment groups. Serial TEG analysis demonstrated significantly higher mean maximal amplitude (maximal amplitude = 68.9 ± 1.7 mm; P < .001), alpha-angle (81.9° ± 0.9°; P < .001), and coagulation index (4.5 ± 0.3; P < .001) 1-week post-injury, which normalized to pre-injury values by 5-weeks post-injury.

Conclusions:

The use of the mast cell stabilizer KF within 2 weeks of injury demonstrated a nonsignificant trend towards reducing joint contracture in a rabbit in vivo model of PTJC. TEG and the in vivo rabbit joint injury model may be valuable in future preclinical studies of venous thromboembolism prevention and furthering our understanding of the pathophysiology of posttraumatic hypercoagulability.

The Dose-Response Effect of the Mast Cell Stabilizer Ketotifen Fumarate on Posttraumatic Joint Contracture: An in Vivo Study in a Rabbit Model

Posttraumatic joint contracture is a debilitating complication following an acute fracture or intra-articular injury that can lead to loss of motion and an inability to complete activities of daily living. In prior studies using an established in vivo model, we found that ketotifen fumarate (KF), a mast cell stabilizer, was associated with a significant reduction in the severity of posttraumatic joint contracture. Our primary research question in the current study was to determine whether a dose-response relationship exists between KF and posttraumatic joint contracture reduction.

Frozen Shoulder: A Systematic Review of Cellular, Molecular, and Metabolic Findings

BACKGROUND

Frozen shoulder is a common, poorly understood condition affecting the shoulder joint, with poor long-term outcomes in some in relation to pain and mobility. Understanding the pathophysiology of frozen shoulder at a cellular level and a molecular level may help in the development of novel treatments. The aim of this study was to perform a systematic review of studies examining the cellular, molecular, and metabolic findings in frozen shoulder.

METHODS

A literature search was conducted using Embase, CINAHL (Cumulative Index of Nursing and Allied Health Literature), and PubMed using relevant terms. Studies were included if they assessed cellular, molecular, or metabolic alterations in tissue or blood samples of patients with frozen shoulder.

RESULTS

Of 4,794 studies identified, 25 were included for analysis. Histological findings included nonspecific chronic inflammation and the proliferation of fibroblasts, adipocytes, and blood vessels. Molecular studies showed increased pro-inflammatory mediators, reduced matrix metalloproteinases (MMPs), and increased activity of factors promoting fibroblast activation and nerve growth. Metabolic alterations included an increase in blood lipids.

CONCLUSIONS

Frozen shoulder is thought to occur after a primary insult to the shoulder triggers a complex cascade and upregulation of growth factors and cytokines with an increased turnover of the extracellular matrix, activation of myofibroblasts with deposition of collagen, and reduced matrix degradation. The presence of a background pro-inflammatory state (e.g., patients with diabetes or hyperlipidemia) may exacerbate these abnormalities. Further work assessing patients in early stages of the disease and comparing the inflammatory or fibrogenic characteristics of the shoulder capsule with those of the other joints may help to determine the initiating factors and to explain the predisposition of the shoulder to stiffness.

CLINICAL RELEVANCE

Our findings may form the basis for identifying new targets for the clinical management of frozen shoulder.

PrEvention of Posttraumatic contractuRes with Ketotifen 1 (PERK 1): A Randomized Clinical Trial

OBJECTIVE

To assess the use of ketotifen fumarate (KF) to reduce posttraumatic contractures after elbow fractures and/or dislocations.

DESIGN

Randomized clinical trial.

SETTING

Three hospitals in Calgary, Canada, including one Level 1 trauma center.

PARTICIPANTS

Adults (n = 151) sustaining operative or nonoperatively managed isolated distal humerus or proximal radius ± ulna fractures or elbow dislocations within 7 days of injury.

INTERVENTIONS

KF 5 mg (n = 74) or lactose placebo (PL, n = 77) orally twice daily for 6 weeks.

MAIN OUTCOMES

Primary outcome elbow flexion-extension arc range of motion (ROM) at 12 weeks postrandomization. Safety measures including serious adverse events and radiographic fracture line disappearance from 2 to 52 weeks postrandomization.

RESULTS

The elbow ROM (mean, confidence interval) was not significantly different between KF (122 degrees, 118-127 degrees) and PL (124 degrees, 119-130 degrees) groups (P = 0.56). There was a significant difference in elbow ROM at 12 weeks postrandomization comparing operative (117 degrees, 112-122 degrees) versus nonoperative groups (128 degrees, 124-133 degrees) irrespective of intervention (P = 0.0011). There were 11 serious adverse events (KF = 6, PL = 5) that were those expected in an elbow fracture population potentially taking KF. There was no statistically significant difference in the rates of these events between the groups. The disappearance of fracture lines over the course of time was similar between groups. There was one nonunion in each group.

CONCLUSIONS

In a population of operative and nonoperatively managed elbow fractures and/or dislocations KF did not reduce posttraumatic contractures. The administration of KF in this population was not found to result in a significantly higher number of major adverse events when compared with placebo.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Reduction of arthrofibrosis utilizing a collagen membrane drug-eluting scaffold with celecoxib and subcutaneous injections with ketotifen

The dense formation of abnormal scar tissue after total knee arthroplasty results in arthrofibrosis, an unfortunate sequela of inflammation. The purpose of this study was to use a validated rabbit model to assess the effects on surgically-induced knee joint contractures of two combined pharmacological interventions: celecoxib (CXB) loaded on an implanted collagen membrane, and subcutaneously (SQ) injected ketotifen. Thirty rabbits were randomly divided into five groups. The first group received no intervention after the index surgery. The remaining four groups underwent intra-articular implantation of collagen membranes loaded with or without CXB at the time of the index surgery; two of which were also treated with SQ ketotifen. Biomechanical joint contracture data were collected at 8, 10, 16, and 24 weeks. At the time of necropsy (24 weeks), posterior capsule tissue was collected for messenger RNA and histopathologic analyses. At 24 weeks, there was a statistically significant increase in passive extension among rabbits in all groups treated with CXB and/or ketotifen compared to those in the contracture control group. There was a statistically significant decrease in COL3A1, COL6A1, and ACTA2 gene expression in the treatment groups compared to the contracture control group (P < .001). Histopathologic data also demonstrated a trend towards decreased fibrous tissue density in the CXB membrane group compared to the vehicle membrane group. The present data suggest that intra-articular placement of a treated collagen membrane blunts the severity of contracture development in a rabbit model of arthrofibrosis, and that ketotifen and CXB may independently contribute to the prevention of arthrofibrosis. Statement of clinical significance: Current literature has demonstrated that arthrofibrosis may affect up to 5% of primary total knee arthroplasty patients. For that reason, novel pharmacologic prophylaxis and treatment modalities are critical to mitigating reoperations and revisions while improving the quality of life for patients with this debilitating condition.

Anti-fibrotic effects of the antihistamine ketotifen in a rabbit model of arthrofibrosis

Aims

Arthrofibrosis is a relatively common complication after joint injuries and surgery, particularly in the knee. The present study used a previously described and validated rabbit model to assess the biomechanical, histopathological, and molecular effects of the mast cell stabilizer ketotifen on surgically induced knee joint contractures in female rabbits.

Methods

A group of 12 skeletally mature rabbits were randomly divided into two groups. One group received subcutaneous (SQ) saline, and a second group received SQ ketotifen injections. Biomechanical data were collected at eight, ten, 16, and 24 weeks. At the time of necropsy, posterior capsule tissue was collected for histopathological and gene expression analyses (messenger RNA (mRNA) and protein).

Results

At the 24-week timepoint, there was a statistically significant increase in passive extension among rabbits treated with ketotifen compared to those treated with saline (p = 0.03). However, no difference in capsular stiffness was detected. Histopathological data failed to demonstrate a decrease in the density of fibrous tissue or a decrease in α-smooth muscle actin (α-SMA) staining with ketotifen treatment. In contrast, tryptase and α-SMA protein expression in the ketotifen group were decreased when compared to saline controls (p = 0.007 and p = 0.01, respectively). Furthermore, there was a significant decrease in α-SMA (ACTA2) gene expression in the ketotifen group compared to the control group (p < 0.001).

Conclusion

Collectively, these data suggest that ketotifen mitigates the severity of contracture formation in a rabbit model of arthrofibrosis.

Contracture and transient receptor potential channel upregulation in the anterior glenohumeral joint capsule of patients with end-stage osteoarthritis

BACKGROUND

During anatomic total shoulder arthroplasty (TSA) for primary glenohumeral osteoarthritis (GHOA), the anterior shoulder joint capsule (ASJC) is characterized grossly by contracture, synovitis, and fibrosis. In tissues that develop fibrosis, there is substantial cross-talk between macrophages, fibroblasts, and myofibroblasts, modulated by calcium signaling and transient receptor potential (TRP) channel signaling. The purpose of this study was to compare and characterize the degree of synovitis, inflammatory infiltrate, and TRP channel expression in ASJC harvested from shoulders with and without primary GHOA.

METHODS

The ASJC was resected from patients undergoing TSA for primary GHOA or other diagnoses and compared with ASJC from cadaveric donors with no history of shoulder pathology. ASJC was evaluated by immunohistochemistry to characterize synovial lining and capsular inflammatory cell infiltrate and fibrosis, and to evaluate for expression of TRPA1, TRPV1, and TRPV4, known to be involved in fibrosis in other tissues. Blinded sections were evaluated by 3 graders using a semiquantitative scale; then results were compared between diagnosis groups using nonparametric methods.

RESULTS

Compared with normal control, the ASJC in primary GHOA had significantly increased synovitis, fibrosis, mixed inflammatory cell infiltrate including multiple macrophages subsets, and upregulation of TRP channel expression.

CONCLUSION

These data support the clinical findings of ASJC and synovial fibrosis in primary GHOA, identify a mixed inflammatory response, and identify dysregulation of TRP channels in the synovium and joint capsule. Further studies will identify the role of synovial and capsular fibrosis early in the development of GHOA.

Psychological Stress and Chronic Urticaria: A Neuro-immuno-cutaneous Crosstalk. A Systematic Review of the Existing Evidence

PURPOSE

It has been observed that certain patients with chronic spontaneous or idiopathic urticaria (CSU/CIU) have a personal history of a significant stressor before urticaria onset, while the prevalence of any psychopathology among these patients is significantly higher than in healthy individuals. Research has confirmed that skin is both an immediate stress perceiver and a target of stress responses. These complex interactions between stress, skin, and the nervous system may contribute to the onset of chronic urticaria. This systematic review investigated the association between CSU/CIU and neuroimmune inflammation with or without evidence of co-existing psychological stress from in vivo and ex vivo studies in human beings.

METHODS

PubMed and Scopus were searched to September 2019 for reports in human beings describing neuroimmune inflammation, stress, and CSU/CIU. A comprehensive search strategy was used that included all the relevant synonyms for the central concept.

FINDINGS

A total of 674 potentially relevant articles were identified. Only 13 satisfied the predefined inclusion criteria and were included in the systematic review. Five of these 13 studies evaluated the correlation between CSU/CIU, stress, and neuro-immune-cutaneous factors, while the remaining 8 focused on the association between CSU/CIU and these factors without examining any evidence of stress.

IMPLICATIONS

The complex neuro-immune-cutaneous model that involves numerous neuropeptides and neurokinins, inflammatory mediators and cells, hypothalamic-pituitary-adrenal axis hormones, and the skin may better explain the underlying pathophysiological mechanisms involved in the onset of urticaria. In addition, the elevated psychological stress level that has been closely related to CSU/CIU could be attributed to the imbalance or irregularity of this neuro-immune-cutaneous circuit. It is still unclear and must be further investigated whether any psychological stress results in or triggers CSU/CIU onset on top of a preexisting neuroimmune dysregulation. Nevertheless, new psycho-phenotypic or neuro-endotypic CSU/CIU subsets should be considered as the era of personalized treatment strategies emerges. A better understanding of CSU/CIU pathophysiology and consideration of the patient as a whole is vital for identifying targets for new potential treatment options.

Inflammatory cytokines and matrix metalloproteinases in the synovial fluid after intra-articular elbow fracture

BACKGROUND AND HYPOTHESIS

Post-traumatic elbow contracture remains a common and challenging complication with often unsatisfactory outcomes. Although the etiology is unknown, elevated or abnormal post-fracture synovial fluid cytokine levels may result in the migration of fibroblasts to the capsule and contribute to capsular pathology. Thus, the purpose of this study was to characterize the cytokine composition in the synovial fluid fracture hematoma of patients with intra-articular elbow fractures.

METHODS

The elbow synovial fluid fracture hematoma of 11 patients with intra-articular elbow fractures was analyzed for CTXII (C-terminal telopeptides of type II collagen [a cartilage breakdown product]) as well as 15 cytokines and matrix metalloproteinases (MMPs) including interferon γ, interleukin (IL) 1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, tumor necrosis factor α, MMP-1, MMP-2, MMP-3, MMP-9, and MMP-10. The uninjured, contralateral elbow served as a matched control. Mean concentrations of each factor were compared between the fluid from fractured elbows and the fluid from control elbows.

RESULTS

The levels of 14 of 15 measured cytokines and MMPs-interferon γ, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, tumor necrosis factor α, MMP-1, MMP-3, MMP-9, and MMP-10-were significantly higher in the fractured elbows. In addition, post hoc power analysis revealed that 10 of 14 significant differences were detected with greater than 90% power. The mean concentration of CTXII was not significantly different between groups.

CONCLUSIONS

These results demonstrate a proinflammatory environment after fracture that may be the catalyst to the development of post-traumatic elbow joint contracture. The cytokines with elevated levels were similar, although not identical, to the cytokines with elevated levels in studies of other weight-bearing joints, indicating the elbow responds uniquely to trauma.

Mechanisms involved in the arthrofibrosis formation and treatments following bone fracture

Arthrofibrosis is a common complication for patients with bone fracture following external and internal fixation. In this review, we summarize the related factors and significant pathways for joint adhesion following fracture surgery. Moreover, the different types of treatments and related preventive measures are also discussed. Many factors related to the development and treatment of arthrofibrosis are discussed in this review in order to provide possible clues for the prospective targets to develop new medication or treatments for preventing or reducing the joint adhesion following orthopedic surgery.

Diabetes mellitus does not increase the risk of knee stiffness after total knee arthroplasty: a meta-analysis of 7 studies including 246 053 cases

Purpose

Methods

Results

Conclusion

Level of evidence

Shared Fate of Meningeal Mast Cells and Sensory Neurons in Migraine

Migraine is a primary headache disorder which has complex neurogenic pathophysiological mechanisms still requiring full elucidation. The sensory nerves and meningeal mast cell couplings in the migraine target tissue are very effective interfaces between the central nervous system and the immune system. These couplings fall into three categories: intimacy, cross-talk and a shared fate. Acting as the immediate call-center of the neuroimmune system, mast cells play fundamental roles in migraine pathophysiology. Considerable evidence shows that neuroinflammation in the meninges is the key element resulting in the sensitization of trigeminal nociceptors. The successive events such as neuropeptide release, vasodilation, plasma protein extravasation, and mast cell degranulation that form the basic characteristics of the inflammation are believed to occur in this persistent pain state. In this regard, mast cells and sensory neurons represent both the target and source of the neuropeptides that play autocrine, paracrine, and neuro-endocrine roles during this inflammatory process. This review intends to contribute to a better understanding of the meningeal mast cell and sensory neuron bi-directional interactions from molecular, cellular, functional points of view. Considering the fact that mast cells play a sine qua non role in expanding the opportunities for targeted new migraine therapies, it is of crucial importance to explore these multi-faceted interactions.

Study of the mechanism underlying hsa-miR338-3p downregulation to promote fibrosis of the synovial tissue in osteoarthritis patients

Osteoarthritis (OA) is a degenerative joint disease characterized by the degradation of joint cartilage, the formation of osteophyma at joint margins, and synovial changes. Whereas lesions of the joint cartilage were the key point of the research and treatment of osteoarthritis before, a recent study showed that the synovium plays a crucial role in the pathological progress of OA. The inflammatory environment in the joints of OA patients always results in the overactivation of fibroblast-like synoviocytes (FLSs), which produce a multitude of inflammatory factors and media, not only leading to the degradation and injury of the cartilage tissue and promoting the development of osteoarthritis but also resulting in synovial fibrosis and joint stiffness. Therefore, the synovium has attracted increasing attention in the research of OA, and the study of the mechanism of activation of FLSs and the fibrosis of joint synovium may shed new light on OA treatment. By using high-throughput screening, we have identified that hsa-miR338-3p is significantly downregulated in the synovial tissue and joint effusion from OA patients. A functional study showed that overexpression of hsa-miR338-3p in the FLSs inhibited the TGF-β1-induced overactivation of the TGF-β/Smad fibrosis regulation pathway by suppressing TRAP-1 expression and thus reducing the TGF-β1-induced activation of the FLSs and the expression of vimentin and collagen I, two fibrosis markers. Meanwhile, a mechanism study also showed that the upregulation of hsa-miR338-3p reduced Smad2/3 phosphorylation by suppressing TRAP-1 and thus inhibited the TGF-β/Smad pathway and TIMP1, a downstream protein. The present study, for the first time, illustrates the role of hsa-miR338-3p in synovial fibrosis in OA patients and the related mechanism, which is of importance to the treatment of OA and its complications by targeting the FLSs and synovial tissue. Hsa-miR338-3p not only has the potential to be a target for the gene therapy of OA but also has the potential to be a new marker for the diagnosis of clinical progression in OA patients.

Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints

Objectives

Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated in vivo animal model of knee arthrofibrosis.

Materials and Methods

A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis.

Results

Animals that underwent arthrotomy had equivalent joint contractures regardless of scaffold implantation (-13.9° versus -10.9°, equivalence limit 15°). Animals that underwent surgery to induce contracture did not demonstrate equivalent joint contractures with (41.8°) or without (53.9°) collagen scaffold implantation. Chondral damage occurred in similar rates with (11 of 48) and without (nine of 48) scaffold implantation. No significant difference in synovitis was noted between groups. Absorption of the collagen scaffold occurred within eight weeks in all animals

Conclusion

Our data suggest that intra-articular implantation of a collagen sponge does not induce synovitis or cartilage damage. Implantation in a native joint does not seem to induce contracture. Implantation of the collagen sponge in a rabbit knee model of contracture may decrease the severity of the contracture.

Cite this article: J. A. Walker, T. J. Ewald, E. Lewallen, A. Van Wijnen, A. D. Hanssen, B. F. Morrey, M. E. Morrey, M. P. Abdel, J. Sanchez-Sotelo. Intra-articular implantation of collagen scaffold carriers is safe in both native and arthrofibrotic rabbit knee joints. Bone Joint Res 2016;6:162–171. DOI: 10.1302/2046-3758.63.BJR-2016-0193.

The posttraumatic stiff elbow: an update

Posttraumatic elbow stiffness is a disabling condition that remains challenging to treat despite improvement of our understanding of the pathogenesis of posttraumatic contractures and new treatment regimens. This review provides an update and overview of the etiology of posttraumatic elbow stiffness, its classification, evaluation, nonoperative and operative treatment, and postoperative management.

Auxiliary proteins that facilitate formation of collagen-rich deposits in the posterior knee capsule in a rabbit-based joint contracture model

Post-traumatic joint contracture is a debilitating consequence of trauma or surgical procedures. It is associated with fibrosis that develops regardless of the nature of initial trauma and results from complex biological processes associated with inflammation and cell activation. These processes accelerate production of structural elements of the extracellular matrix, particularly collagen fibrils. Although the increased production of collagenous proteins has been demonstrated in tissues of contracted joints, researchers have not yet determined the complex protein machinery needed for the biosynthesis of collagen molecules and for their assembly into fibrils. Consequently, the purpose of our study was to investigate key enzymes and protein chaperones needed to produce collagen-rich deposits. Using a rabbit model of joint contracture, our biochemical and histological assays indicated changes in the expression patterns of heat shock protein 47 and the α-subunit of prolyl 4-hydroxylase, key proteins in processing nascent collagen chains. Moreover, our study shows that the abnormal organization of collagen fibrils in the posterior capsules of injured knees, rather than excessive formation of fibril-stabilizing cross-links, may be a key reason for observed changes in the mechanical characteristics of injured joints. This result sheds new light on pathomechanisms of joint contraction, and identifies potentially attractive anti-fibrotic targets.

Neuroinflammatory Mechanisms of Connective Tissue Fibrosis: Targeting Neurogenic and Mast Cell Contributions

Significance: The pathogenesis of fibrogenic wound and connective tissue healing is complex and incompletely understood. Common observations across a vast array of human and animal models of fibroproliferative conditions suggest neuroinflammatory mechanisms are important upstream fibrogenic events. Recent Advances: As detailed in this review, mast cell hyperplasia is a common observation in fibrotic tissue. Recent investigations in human and preclinical models of hypertrophic wound healing and post-traumatic joint fibrosis provides evidence that fibrogenesis is governed by a maladaptive neuropeptide-mast cell-myofibroblast signaling pathway. Critical Issues: The blockade and manipulation of these factors is providing promising evidence that if timed correctly, the fibrogenic process can be appropriately regulated. Clinically, abnormal fibrogenic healing responses are not ubiquitous to all patients and the identification of those at-risk remains an area of priority. Future Directions: Ultimately, an integrated appreciation of the common pathobiology shared by many fibrogenic connective tissue conditions may provide a scientific framework to facilitate the development of novel antifibrotic prevention and treatment strategies.

A myofibroblast-mast cell-neuropeptide axis of fibrosis in post-traumatic joint contractures: an in vitro analysis of mechanistic components

Previous studies have implicated a myofibroblast-mast cell-neuropeptide axis of fibrosis in pathologic joint capsules from post-traumatic contractures. The hypothesis to be tested is that joint capsule cells (JC) from human elbows with post-traumatic contractures and their interactions with mast cells (MC) and neuropeptides in the microenvironment underlie the pathogenesis of contractures. The hypothesis was tested using an in vitro collagen gel contraction model. The JC were isolated from human elbow capsules and mixed with neutralized PureCol collagen I. The gels were treated in various ways, including addition of MC (HMC-1), the neuropeptide substance P (SP), an NK1 receptor (SP receptor) antagonist RP67580 and the mast cell stabilizer ketotifen fumarate (KF). The collagen gels were released from the wells and gel size (contraction) was measured optically at multiple time points. The JC contracted collagen gels in a dose-dependent manner. This was enhanced in the presence of MC and increased further with SP. Increasing concentrations of the SP receptor antagonist, RP67580 or the mast cell stabilizer, KF decreased the magnitude of contraction. These observations identify putative mechanistic components of a myofibroblast-mast cell-neuropeptide axis of fibrosis in the joint capsules in post-traumatic contractures and potential prophylactic or therapeutic interventions.

Reduction of intraarticular adhesion by topical application of colchicine following knee surgery in rabbits

The aim of this study was to investigate the efficacy of topical application of colchicine in reducing intraarticular adhesion in rabbits. Thirty-six rabbits were randomly and equally divided into three groups. An approximately 10 × 10 mm² area of cortical bone was removed from both sides of the left femoral condyle, and the cancellous bone underneath was exposed. Cotton pads soaked with different concentrations of colchicine or saline were applied to the decorticated areas for 10 minutes. The surgical limb was fixed in a flexed position for 4 weeks postoperatively. To evaluate knee intraarticular adhesion, we performed macroscopic evaluation, histological and collagen density analyses, hydroxyproline content determination, fibroblast counting and densitometric analyses. The results showed that loose collagen tissues with little or no adhesion were present around the decorticated areas in the group treated with 0.5 mg/ml colchicine. The intraarticular adhesion score, hydroxyproline content, number of fibroblasts and densitometric value in this group were also significantly lower than those in the other groups. There was moderate intraarticular adhesion in the group treated with 0.1 mg/ml colchicine. However, dense scar tissue with dense adhesions was found in the control group. In conclusion, topical application of 0.5 mg/ml colchicine may reduce knee intraarticular adhesion.

The outcome of open elbow arthrolysis: comparison of four different approaches based on one hundred cases

PURPOSE

The aim of this study was to evaluate the results of elbow arthrolysis according to the surgical approach, durability after arthrolysis and the severity of contracture.

METHODS

The study includes a cohort of 100 consecutive patients treated in our institution between 1986 and 2008. The indication for surgery was loss of mobility. This was the result of fractures, dislocation, simultaneous fracture/dislocation or other non-traumatic causes. All patients underwent open elbow release via one of four approaches (42 lateral, 44 medial, six combined medial-lateral and eight posterior). They were clinically evaluated at a minimum of 24 months after arthrolysis.

RESULTS

The average ranges of elbow extension, flexion and arc of motion had increased significantly at the follow up, respectively, by 20°, 16° and 36°. No significant difference was found with regard to surgical approach. However, we noticed significant deterioration of intra-operative average extension and arc of motion (AOM) over the follow up period, respectively, by 13° and 14°. The number of patients with AOM of 100° or more increased from three patients preoperatively to 28 postoperatively.

CONCLUSIONS

Open elbow arthrolysis is a successful method of treatment of elbow contracture. Results are durable, but there is some postoperative deterioration of extension gained during surgery. We may anticipate that at the final stage we shall obtain an average of 86% of intra-operative arc of motion. Patients with the most severe contractures have the best gains.

Prevention and treatment of elbow stiffness: a 5-year update

Elbow stiffness is a challenging and common problem faced by upper extremity surgeons. Although functional improvements can be made with both nonsurgical and surgical management strategies, physicians must remain vigilant with efforts to prevent stiffness before it starts. Recent advancements in the biology and pathology of elbow contracture have led to improved understanding of this difficult problem, and they may lead to future breakthroughs in the prevention and treatment of elbow stiffness. This article serves as an update to our previous review of elbow stiffness, focusing on recent advancements in the past 5 years, as well as updating our current algorithm for treatment.

Posttraumatic elbow joint contractures: defining pathologic capsular mechanisms and potential future treatment paradigms

The Andrew J. Weiland Medal is presented by the American Society for Surgery of the Hand to a midcareer researcher who is dedicated to advancing patient care in the field of hand surgery. This essay, awarded the Weiland Medal in 2012, focuses on posttraumatic elbow joint contractures. Joint contractures are well known to hand surgeons because they limit function of our patients. There is a thorough understanding of the pathoanatomy underlying joint contractures. However, the mechanisms leading to the pathoanatomy are either unknown or partially understood, depending on the etiology of the particular clinical condition. This review describes our research over the past 14 years on posttraumatic elbow joint contractures. It defines pathologic cellular, matrix, and growth factor changes in the joint capsule, elaborates on the development of an animal model of posttraumatic joint contractures, presents an evaluation of a potential prevention strategy based on our research, and outlines future plans to bring this work to the clinical realm for the benefit of patients.

Posttraumatic elbow contractures: targeting neuroinflammatory fibrogenic mechanisms

Posttraumatic elbow stiffness remains a common and challenging clinical problem. In the setting of a congruent articular surface, the joint capsule is regarded as the major motion-limiting anatomic structure. The affected joint capsule is characterized by irreversible biomechanical and biochemical fibrogenic changes strikingly similar to those observed in many other fibroproliferative human conditions. Studies in humans and preclinical animal models are providing emergent evidence that neuroinflammatory mechanisms are critical upstream events in the pathogenesis of posttraumatic connective tissue fibrogenesis. Maladaptive recruitment and activation of mast cell infiltrates coupled with the aberrant expression of growth factors such as transforming growth factor-beta, nerve growth factor, and neuropeptides such as substance P are common observations in posttraumatic joint contractures and many other fibroproliferative disorders. Blockade of these factors is providing promising evidence that if treatment is timed correctly, the fibrogenic process can be interrupted or impeded. This review serves to highlight opportunities derived from these recent discoveries across many aberrant fibrogenic disorders as we strive to develop novel, targeted antifibrotic prevention and treatment strategies for posttraumatic elbow stiffness.

Suppression of mast cell activity contributes to the osteoprotective effect of an herbal formula containing Herba Epimedii, Fructus Ligustri Lucidi and Fructus Psoraleae

Objectives

Mast cells are believed to contribute to the pathogenesis of osteoporosis as their number is increased in osteoporotic bones. Herba Epimedii, Fructus Ligustri Lucidi and Fructus Psoraleae are three Chinese herbs traditionally for tonifying the ‘kidney system’ and a herbal formula (ELP) containing the respective herbs at the weight ratio of 5 : 4 : 1 was shown to prevent osteoporosis. This study evaluated if suppression of mast cell accumulation and activity contribute to the anti-osteoporotic action of ELP.

Methods

The herbs were boiled under reflux to produce the aqueous extract that was further concentrated under reduced pressure and lyophilized. An in-vivo rat osteoporosis model using hind limb unloading was employed for studying the accumulation of mast cells. The human mast cell line, LAD2, was employed to evaluate the mast cell modulating action of ELP.

Key findings

Mast cell number in the tibiae of hind limb unloaded rats increased significantly during the course of osteoporosis. ELP treatment (10 g/kg/day) prevented both osteoporosis and mast cell accumulation in these rats. Furthermore, ELP significantly inhibited histamine and tumour necrosis factor-α release from LAD2 cells.

Conclusion

Mast cells contributed to hormone independent osteoporosis. The suppression of mast cell accumulation and activation may contribute to the anti-osteoporotic action of ELP.

Surgical capsular release reduces flexion contracture in a rabbit model of arthrofibrosis

Animal models of joint contracture may be used to elucidate the mechanisms of arthrofibrosis. Patients with joint contracture commonly undergo surgical capsular release. Previous animal models of joint contracture do not simulate this aspect of arthrofibrosis. We hypothesize that a surgical capsular release will decrease the severity of arthrofibrosis in this rabbit model. A capsular contracture was surgically created in 20 skeletally mature rabbits. Eight weeks later, ten rabbits underwent capsular release, which consisted of elevation of the posterior capsule through a lateral incision and manipulation under anesthesia. Ten rabbits had a sham incision, without release (control group). Immediately after release or sham surgery, extension loss (calculated by subtracting the knee extension angle (degrees) of the operative limb from the nonoperative, contralateral limb) was measured using fluoroscopy. All animals were sacrificed following 16 weeks of postoperative free cage activity. At sacrifice, joint contracture was measured using a custom, calibrated device. The histology of the posterior joint capsule was assessed at sacrifice. All animals survived both operations without complications. Immediately after surgical release or sham surgery, the average extension loss was 129.2 ± 10.7° in the control group versus 29.6 ± 8.2° in the capsular release group (p = 0.0002). Following 16 weeks of remobilization, the average extension loss of the control and capsular release animals were 49.0 ± 12.7° and 36.5 ± 14.2°, respectively (p = 0.035). There were no histological differences between the two groups. In this animal model, a surgical capsular release decreased the extension loss (flexion contracture) immediately after surgery, as well as following sixteen weeks of remobilization. There were no histological changes detected in the posterior joint capsule.

Posttraumatic elbow stiffness

Early posttraumatic elbow contractures may be treated with a combination of manipulation with the patient under anesthesia followed by bracing.Extrinsic contractures of the elbow may be treated with open or arthroscopic release, whereas intrinsic and combined contractures may require tissue release as well as partial or total arthroplasty.

Coexistence of fibrotic and chondrogenic process in the capsule of idiopathic frozen shoulders

OBJECTIVE

To analyze changes in the capsule from idiopathic frozen shoulders and clarify their etiology.

MATERIALS AND METHODS

Samples (the rotator interval capsule, middle glenohumeral ligament (MGHL), and inferior glenohumeral ligament (IGHL)) were collected from 12 idiopathic frozen shoulders with severe stiffness and 18 shoulders with rotator cuff tears as a control. The number of cells was counted and the tissue elasticity of the samples was calculated by scanning acoustic microscopy (SAM). The amount of glycosaminoglycan content was assessed by alcian blue staining. Gene and protein expressions related to fibrosis, inflammation, and chondrogenesis were analyzed by quantitative polymerase chain reaction (qPCR) and immunohistochemistry (IHC). Furthermore, the total genes of the two groups were compared by DNA microarray analysis.

RESULTS

The number of cells was significantly higher and the capsular tissue was significantly stiffer in idiopathic frozen shoulders compared with shoulders with rotator cuff tears. Staining intensity of alcian blue was significantly stronger in idiopathic frozen shoulders. Gene expressions related to fibrosis, inflammation, and chondrogenesis were significantly higher in idiopathic frozen shoulders compared with shoulders with rotator cuff tears assessed by both qPCR and DNA microarray analysis.

CONCLUSION

In addition to fibrosis and inflammation, which used to be considered the main pathology of frozen shoulders, chondrogenesis is likely to have a critical role in pathogenesis of idiopathic frozen shoulders.

The mast cell stabilizer ketotifen reduces joint capsule fibrosis in a rabbit model of post-traumatic joint contractures

OBJECTIVES

Using a rabbit model of post-traumatic joint contractures, we investigated whether treatment with a mast cell stabilizer after joint injury would lessen the molecular manifestations of joint capsule fibrosis.

METHODS

Surgical joint injury was used to create stable post-traumatic contractures of the knee in skeletally mature New Zealand white rabbits. Four groups of animals were studied: a non-operated control group (n = 8), an operated contracture group (n = 13) and two operated groups treated with the mast cell stabilizer, ketotifen, at doses of 0.5 mg/kg (n = 9) and 1.0 mg/kg (n = 9) twice daily. Joint capsule fibrosis was assessed by quantifying the mRNA and protein levels of α-SMA, tryptase, TGF-β1, collagen I and collagen III. Significance was tested using an ANOVA analysis of variance.

RESULTS

The protein and mRNA levels of α-SMA, TGF-β1, tryptase and collagen I and III were significantly elevated in the operated contracture group compared to control (p < 0.01). In both ketotifen-treated groups, protein and mRNA levels of α-SMA, TGF-β1 and collagen I were significantly reduced compared to the operated contracture group (p < 0.01).

CONCLUSIONS

These data suggest an inflammatory pathway mediated by mast cell activation is involved in joint capsule fibrosis after traumatic injury.

Does the source of hemarthrosis influence posttraumatic joint contracture and biomechanical properties of the joint?

BACKGROUND

Posttraumatic joint contracture is a common complication of intraarticular injuries and an associated traumatic hemarthrosis could be of importance for its development. The purpose of this investigation was to determine whether the source of the hemarthrosis (peripheral blood vs. bleeding from the bone marrow) affects the amount of contracture and its reversibility and biomechanical properties.

METHODS

46 New Zealand White rabbits were divided in 6 groups and 33 underwent 8 weeks immobilization with either hemarthrosis from bone marrow or peripheral blood. 16 rabbits underwent remobilization for another 8 weeks. 7 animals had only hemarthrosis (bone marrow) for 8 weeks, while 6 were used as controls. Analysis included mean contracture angle and biomechanical variables.

FINDINGS

The immobilized animals had an increased contracture angle, the knee angle vs. force curve had a greater hysteresis and showed higher initial stiffness. There was no difference in biomechanical properties of the knee between the different types of hemarthroses. After 8 weeks remobilization most biomechanical properties were not different from control.

INTERPRETATION

The origin of hemarthrosis, and therewith the presence of marrow-derived factors and pluripotential cells from bone marrow, does not seem to affect the severity of joint contractures nor their reversibility.

Neuropeptide, mast cell, and myofibroblast expression after rabbit deep flexor tendon repair

PURPOSE

Increased numbers of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers have been found in a number of fibrotic processes in connective tissues. The purpose of the present study was to investigate the occurrence of factors implicated in a hypothesized profibrotic neuropeptide-mast cell-myofibroblast pathway in deep flexor tendon healing.

METHODS

In a rabbit model of flexor tendon injury, with repair of the sharply transected deep flexor tendon using a modified Kessler and a running circumferential peripheral suture, segments of flexor tendons and sheaths were analyzed. The time points chosen-3, 6, 21, and 42 days after tendon repair-represent different stages in tendon healing. The messenger RNA levels of transforming growth factor-β1 and α-smooth muscle actin were measured with conventional reverse transcription-polymerase chain reaction, and the numbers of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers were determined with immunohistochemistry.

RESULTS

The messenger RNA levels for transforming growth factor-β1 and the myofibroblast marker α-smooth muscle actin were significantly increased in deep flexor tendons after injury and repair, at all studied time points, but remained unchanged or even down-regulated in the sheaths. Myofibroblasts, mast cells, and neuropeptide-containing nerve fibers all increased significantly in the healing tendons, exhibiting similar patterns of change in percentages of total cell number over time, reaching levels resembling that of the tendon sheaths with 33% to 50% of the total cell population.

CONCLUSIONS

After injury to the deep flexor tendon in a rabbit model, the proportion of myofibroblasts, mast cells, and neuropeptide-containing nerve fibers increases significantly. These findings support the hypothesis that the profibrotic neuropeptide-mast cell-myofibroblast pathway is activated in deep flexor tendon healing.

The mast cell stabilizer ketotifen fumarate lessens contracture severity and myofibroblast hyperplasia: a study of a rabbit model of posttraumatic joint contractures

BACKGROUND

The propensity of joints to become stiff after trauma is widely appreciated, and the joint capsule is commonly recognized as the major motion-limiting anatomical structure. Affected joint capsules become fibrotic, characterized by myofibroblast and collagen hyperplasia. Mast cell hyperplasia is common within fibrotic tissue, and mast cells are known to synthesize many profibrotic mediators. We hypothesized that mast cell inhibition after skeletal injury would lessen contracture severity and reduce myofibroblast hyperplasia within the joint capsule.

METHODS

Posttraumatic contractures of the knee were created with use of a combination of intra-articular injury and internal immobilization in skeletally mature New Zealand White rabbits. Four groups of animals were studied: a nonoperative control group, a group with the operatively created contracture and no pharmacological treatment (the operative contracture group), and two groups with the operatively created contracture that were treated with a mast cell stabilizer, ketotifen fumarate, at a dose of either 0.5 or 1.0 mg/kg twice daily (the 0.5-mg/kg and 1.0-mg/kg ketotifen groups). After eight weeks of immobilization, flexion contractures were measured and the posterior aspect of the joint capsule was harvested for quantification of myofibroblast and mast cell numbers.

RESULTS

Flexion contractures developed in the operative contracture group (mean and standard deviation, 58 degrees +/- 14 degrees ), and the severity of the contractures was reduced in both the group treated with 0.5 mg/kg of ketotifen (42 degrees +/- 17 degrees ) and the group treated with 1.0 mg/kg of ketotifen (45 degrees +/- 10 degrees ) (p < 0.02). The joint capsule myofibroblast and mast cell numbers in the operative contracture group were significantly increased compared with the values in the control group (p < 0.001), and the myofibroblast and mast cell numbers in both ketotifen groups were significantly reduced compared with the values in the operative contracture group (p < 0.001).

CONCLUSIONS

The use of a mast cell stabilizer, ketotifen, was effective in reducing the biomechanical and cellular manifestations of joint capsule fibrosis in a rabbit model of posttraumatic joint contracture. This finding suggests that an inflammatory pathway, mediated by mast cell activation, is involved in the induction of joint capsule fibrosis after traumatic injury.