Bilateral first metatarsophalangeal joint arthrodesis: An investigation of functional, surgical and radiological outcomes

BACKGROUND

First metatarsophalangeal joint (MTPJ) arthrodesis is a commonly utilised procedure. In this study, the authors aim to explore functional outcomes of patients undergoing nonsynchronous bilateral first MTPJ arthrodesis under the care of a single surgeon using a compression screw/locking plate construct.

METHODS

This is a prospectively collected, retrospectively analysed case series of fifty five patients who underwent bilateral nonsynchronous first MTPJ arthrodesis. Clinical and radiological outcomes were assessed preoperatively and at a minimum of two years postoperatively. Clinical outcomes were assessed using the Foot and Ankle Outcome Score (FAOS), the Self-Reported Foot and Ankle Score (SEFAS) and the Sports Questionnaire version 1 (SQ). Postoperative radiographs were used to assess evidence of union and compare both hallux valgus and intermetatarsal angles. Removal of hardware, revision surgery and correction of deformities were also recorded.

RESULTS

Fifty five patients were included in the study. There was statistically significant improvements in all five facets of the FAOS (p value < 0.05). The mean postoperative SEFAS was 45.1. In total, patients participated in thirteen different sporting activities. This represented 92 patient specific activities preoperatively and 104 postoperatively. The most common activities were walking, cycling and swimming. Overall, 94.5% (N = 52) of the cohort were satisfied with their return to sport while 98.2% (N = 54) would recommend bilateral first MTPJ arthrodesis. Mean reductions in hallux valgus angles and intermetatarsal angles were noted at 18.87 and 4.69 degrees respectively. There was one non-union in the cohort which required revision surgery. One patient required removal of hardware.

CONCLUSIONS

Bilateral first MTPJ arthrodesis is a safe and effective surgical option for patients with bilateral first MTPJ pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes and allows patients reliably return to physical activities.

Outcomes following tibiotalocalcaneal arthrodesis using a solid posterior offset intramedullary nail in 44 patients with a minimum 30-month follow-up

BACKGROUND

Tibiotalocalcaneal arthrodesis is frequently performed by foot and ankle surgeons in the management of complex ankle and hindfoot pathology. In this study, the authors describe the clinical and radiological outcomes of tibiotalocalcaneal arthrodesis using a solid posterior offset hindfoot arthrodesis nail.

METHODS

Forty-four consecutive patients underwent tibiotalocalcaneal arthrodesis by a single surgeon operating in two centers. Clinical and radiological outcomes were assessed preoperatively and at 6-month, 12-month and final follow-up (mean 47 months). Clinical outcomes were assessed with VAS, AOFAS and MOXFQ scores. Serial radiographs were used to assess union at each follow-up visit.

RESULTS

Forty-four patients attended 12-month and final follow-up (mean 47 months). A total of 44 (100%) ankle joints and 44 (100%) subtalar joints were completely united at 12-month follow-up. The VAS score improved significantly from a mean of 6.5 preoperatively to a mean of 0.98 at final follow-up (P = <0.0001). AOFAS score improved significantly from a mean of 36.4 preoperatively to a mean of 73 at final follow-up (P = <0.0001). MOXFQ score improved significantly from a mean of 44.5 preoperatively to a mean of 12.7 at final follow-up (P = <0.0001). The mean change in frontal plane alignment was 5.7 degrees (P = 0.005). A total of 6 patients (13.6%) had an adverse event during the course of the study.

CONCLUSIONS

Tibiotalocalcaneal arthrodesis with a solid posterior offset hindfoot arthrodesis nail is a safe and effective surgical option for patients with severe ankle and hindfoot pathology. It has a high union rate, low complication rate and significantly improves clinical outcomes.

Improved adherence to hip fracture standards reduces mortality after hip fractures

BACKGROUND

Hip fractures are increasing in incidence due to increasing life expectancy. Mortality continues to improve but it is important to explore which factors are responsible for driving improvements.

METHODS

A cohort of hip fracture patients predating SARS-CoV-2 was examined to determine the predictors of adherence to the six Irish Hip Fracture Standards (IHFS) and the impact of adherence on short (30 day) and long term (1 year) mortality. Our primary aim was assess the impact of a single HFS and cumulative number of HFS on mortality after hip fracture. Our secondary aim was to determine the impact of the HFS which are intrinsically linked to specialist Geriatric care.

RESULTS

Across 962 patients, over 5 years, the factors which were associated with adherence to HFS were female gender, increasing ASA grade and being nursed on an orthopaedic ward. Patients with increasing ASA were more likely to have met HFS 4-6 (Geriatrician review HFS4, bone health HFS5 & specialist falls assessment HFS6), less likely to have surgery within 48 h are more likely to develop a pressure ulcer. If the patient was not nursed on an orthopaedic ward all HFS were less likely to be met. At 30 days HFS 4-6 were associated with a statistically significant odds ratio (OR) of being alive, while at one year HFS 1 (admitted to an orthopaedic ward within 4 h), 5 and 6 were associated with a statistically significant OR of being alive. As increasing numbers of hip fracture standards were met patients were more likely to be alive at 30 days and one year.

CONCLUSION

This study has identified that improved adherence to hip fracture standards are associated with improved mortality at 30 days and one year.

Modern Internet Search Analytics and Osseointegration: What are Patients Asking and Reading Online?

Background

Osseointegration (OI) limb has been performed for over 30 years and is an example of an advance in technology and surgical technique which has led to improvements in patient mobility and quality of life. An increasing number of patients seek information about osseointegration. The aim of this study was to categorise the most frequently asked questions by patients using the Google search engine and the most frequently accessed websites with the highest return on answers. The secondary aims of this study were to assess the quality of the information provided on those websites and to stratify, by category, which websites provide the best quality information.

Materials and methods

Ten permutations and conjugations of the word 'osseointegration' were entered into Google. The first fifty 'People also ask' and associated websites by Google's machine learning and natural language processing engine were collected for each search term. The Rothwell classification system of questions by topic (Fact, Value, Policy) and websites by category was used (Commercial, Academic, Medical Practice, Single Surgeon Personal, Government, Social Media). Website quality was assessed using the Journal of the American Medical Association (JAMA) benchmark criteria (Likert-style rating 0-4). Pearson's Chi-squared and Student's t-tests were performed for statistical analysis as appropriate (significance, p < 0.05).

Results

The 10 search terms generated 454 questions and referenced 408 websites. Of the 454 questions generated, the most common question categories were fact (70.8%), value (19.2%), and policy (10%). The most common website type was social media (37.4%). The most common question types were technical details (30.4%), specific activity (20.6%), and cost (14.1%). Only 1.6% of questions related to risks and complications. Generally, website quality was poor with 64.1% having a JAMA score of 0 or 1. Websites that were categorised as 'Government' had the highest overall JAMA scores: 71.4% had a score of 4.

Conclusion

Based on Google search engine's results, the most commonly asked questions about osteointegration related to technical details, specific activities and cost; only 1.6% related to risks and complications. Interestingly, social media websites represented the highest volume of search result referrals. Overall, the quality of websites was poor with the most factual information coming from governmental websites.

How to cite this article

Murphy EP, Sheridan GA, Page BJ, et al. Modern Internet Search Analytics and Osseointegration: What Are Patients Asking and Reading Online? Strategies Trauma Limb Reconstr 2023;18(3):163-168.

NR4A1-3 nuclear receptor activity and immune cell dysregulation in rheumatic diseases

The development and progression of immune-mediated rheumatic disease (IMRD) involves dysfunction of innate and adaptive immune cell populations leading to altered responses including inflammasome activation, dysregulated cytokine networks, increased immune cell numbers and multifaceted cell-cell communication. Several rheumatic diseases are further characterized by the presence of autoantibodies, immune complex mediated complement activation and the deficit of peripheral immune tolerance due to reduced regulatory T-lymphocyte cell function. Ultimately, in rheumatic disease the loss in cellular and tissue homeostasis culminates in the advancement of chronic inflammation. The three members of the NR4A subfamily of nuclear receptors are immediate early genes, and act as potent transcriptional responders to changes in the cellular and tissue microenvironment. Subfamily members are rapidly expressed in diseases characterized by inflammation and function to control the differentiation and activity of innate and adaptive immune cells in a cell-type and cell-context specific manner. Rheumatic disease including rheumatoid-, psoriatic-, osteo-arthritis and systemic sclerosis display altered NR4A1-3 activity in controlling immune cell migration and function, production of paracrine signaling molecules, synovial tissue hyperplasia, and regulating cartilage turn-over in vivo. Additionally, NR4A1-3 activities mediate cytokine, prostanoid and growth factor signaling to control angiogenesis, modulate the regulatory functions of mesenchymal stromal cells, alter the activation status of dendritic cells, influence the generation of peripheral myeloid and T-lymphocyte lineages and promote the maintenance of functional regulatory T-cells. Further reports uncover the potential of moderating NR4A 1-3 receptors as therapeutic targets in altering immune tolerance, pathological angiogenesis and controlling inflammation in several models of disease.

Total Knee Arthroplasty in Hemophilia: Survivorship and Outcomes-A Systematic Review and Meta-Analysis

BACKGROUND

Patients with hemophilia (PWHs) may experience spontaneous or traumatic bleeding episodes. Recurrent bleeding can lead to end-stage hemophilic arthropathy and total knee replacement (TKR) provides an effective treatment. The aim of this study is to investigate outcomes in PWHs who undergo TKR.

METHODS

A systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Study outcomes included patient-reported functional outcomes, implant survivorship, and complications. Subgroup analysis was performed assessing the effect of recombinant prophylaxis medication by comparing studies that included only TKRs performed after the year 2000 (period A), to those that included TKRs before 2000 (period B).

RESULTS

Twenty-eight studies were included, with a total of 1210 TKRs performed in 917 PWHs. The mean age of patients was 38.5 years (standard deviation 5.1) with a mean length of follow-up of 7.1 years (standard deviation 2.9). The total complication rate was 28.7%, with 19.3% requiring a further procedure. Hospital for Special Surgery Knee Score improved by 44.6 points (confidence interval 38.9-50.4) and Knee Society Score function improved by 35.9 points (confidence interval 30.1-41.8). Total range of motion improved by 22.3°. The most common complication was post-operative hemarthrosis (7.6%, 92 TKRs). Deep infection (6.2% vs 3.9%) and aseptic loosening (3.8% vs 2.1%) rates fell between period B and period A.

CONCLUSION

TKR in PWHs is a successful procedure improving function, reducing pain, and improving range of motion. PWHs undergo TKR at a younger age and have a higher risk of complications, though contemporary treatment has reduced these risks. PWHs can expect similar survivorship to the general population.

Collagenase and the Treatment of Dupuytren Contracture: Efficacy of Treatment and Patient Satisfaction

Background: Collagenase clostridium histolyticum has become a widely used treatment in the management of Dupuytren disease. The aims of this study are to assess the immediate success of treatment of Dupuytren contracture with collagenase injection, to measure long-term patient-rated outcomes, to determine whether the risk factors for the disease impacted outcomes and to report complications of collagenase treatment. Methods: A prospective study was performed in a tertiary referral centre. Measurements were recorded pre-treatment, day 1 and day 90. Patient-rated outcome scores were measured using Disability of the Arm, Shoulder and Hand questionnaire (DASH) and the Michigan Hand Questionnaire (MHQ) at minimum 36 months post-injection. Results: The study included 45 patients with 53 hands with a mean age of 65.7 years. The treatment was successful in 62% of patients with the greatest improvement in the metacarpal-phalangeal joint of the little finger. Diabetes, epilepsy, gender, alcohol intake and positive family history had no statistically significant predictive value on successful outcomes. Patient satisfaction at 41 months was high with mean MHQ score of 97.3. Conclusions: Collagenase is effective in the treatment of Dupuytren contracture, with disease involving the little finger showing the greatest benefit. Risk factors for development of Dupuytren disease had no effect on successful outcome and long-term satisfaction rates are high. Level of Evidence: Level III (Therapeutic).

Functional Capabilities After First Metatarsal Phalangeal Joint Arthrodesis Using a Locking Plate and Compression Screw Construct

Arthrodesis of the first metatarsal phalangeal joint (MTPJ) is a widely utilized surgical procedure for a wide array of metatarsal pathologies. This study aims to explore the functional limitations following first MTPJ arthrodesis, overall satisfaction and patient's abilities to achieve activities of daily living (ADL). This prospective cohort study assessed functional limitations as well as footwear and lifestyle restrictions using several questionnaires. One hundred and three participants who had a first MTPJ arthrodesis under the care of a single surgeon were recruited. Pre- and postoperative patient-reported outcome measures were recorded. The American Orthopaedic Foot and Ankle Score (AOFAS) and the Manchester-Oxford Foot Questionnaire were also used to further examine functional status. Hallux valgus angle (HVA) and intermetatarsal angle (IMA) were compared using preoperative and postoperative weightbearing radiographs and successful fusion was recorded. Complications were documented and are discussed in detail. The duration of follow-up was more than 12 months. There was one nonunion in the cohort while 2 patients experienced delay to fusion. Approximately 97% of patients were very satisfied with the procedure and their ability to achieve ADLs post operatively. A further 82.5% of patients were able to return to wearing nonadaptive footwear. The mean reduction in HVA and IMA was 21.78° and 6.84°, respectively. This study demonstrates the safe and successful use of a compression screw/locking plate construct for arthrodesis of the first MTPJ. Furthermore, the study provides clear evidence of high levels of functionality after the procedure with statistically significant differences (p value <.05) in all 4 facets of the AOFAS questionnaire as well as several notable differences in activity levels and footwear restrictions pre and postoperatively.

Does Proximal Femoral Morphology Impact Morbidity and Mortality? A Cohort Study of Uncemented Hemiarthroplasties in the Treatment of Femoral Neck Fractures

Background

To assess outcomes after uncemented hemiarthroplasty stems in the treatment of intracapsular femoral neck fractures over an 11-year period. Mortality rates were assessed, and whether proximal femoral geometry and stem alignment were factors in intraoperative or postoperative periprosthetic fracture (PPF) needs to be identified.

Materials and Methods

A retrospective single-center observational study was conducted of all patients who underwent intracapsular femoral neck fracture treatment using an uncemented prosthesis between January 2008 and December 2018. Primary endpoints included mortality rate, Dorr classification, prosthesis alignment, intraoperative fracture, and reoperation rate for any reason. Subanalysis on collared and uncollared implants was also conducted. Multivariate logistic regression was performed based on Dorr classification for stem alignment, fracture incidence, reoperation rate, implant sizing, and patient mortality.

Results

A total of 536 patients received an uncemented hemiarthroplasty in the study period. The mean patients age was 80.4 years, of which 71% were female. The 30-day mortality rate was 5.2%, with no deaths on day zero or day one. Twenty patients (3.7%) sustained an intraoperative calcar fracture, and 14 patients a PPF (2.6%) at a mean of 1.3 years from surgery. Dorr C type femurs were more likely to develop a PPF (P = .001), while valgus stem alignment was associated with PPF (P = .049).

Conclusions

This implant has low reoperation rates, low early postoperative mortality, and low 30-day mortality. This large single-center study provides up-to-date information using a contemporary stem in patients with multiple comorbidities. Dorr C femoral morphology and valgus stem malalignment were risk factors for postoperative fractures.

Transcriptional Profiling of Monocytes Deficient in Nuclear Orphan Receptors NR4A2 and NR4A3 Reveals Distinct Signalling Roles Related to Antigen Presentation and Viral Response

The nuclear receptor sub-family 4 group A (NR4A) family are early response genes that encode proteins that are activated in several tissues/cells in response to a variety of stressors. The NR4A family comprises NR4A1, NR4A2 and NR4A3 of which NR4A2 and NR4A3 are under researched and less understood, particularly in the context of immune cells. NR4A expression is associated with multiple diseases e.g. arthritis and atherosclerosis and the development of NR4A-targetting molecules as therapeutics is a current focus in this research field. Here, we use a combination of RNA-sequencing coupled with strategic bioinformatic analysis to investigate the down-stream effects of NR4A2 and NR4A3 in monocytes and dissect their common and distinct signalling roles. Our data reveals that NR4A2 and NR4A3 depletion has a robust and broad-reaching effect on transcription in both the unstimulated state and in the presence of LPS. Interestingly, many of the genes affected were present in both the unstimulated and stimulated states revealing a previously unappreciated role for the NR4As in unstimulated cells. Strategic clustering and bioinformatic analysis identified both distinct and common transcriptional roles for NR4A2 and NR4A3 in monocytes. NR4A2 notably was linked by both bioinformatic clustering analysis and transcription factor interactome analysis to pathways associated with antigen presentation and regulation of MHC genes. NR4A3 in contrast was more closely linked to pathways associated with viral response. Functional studies further support our data analysis pointing towards preferential/selective roles for NR4A2 in the regulation of antigen processing with common roles for NR4A2 and NR4A3 evident with respect to cell migration. Taken together this study provides novel mechanistic insights into the role of the enigmatic nuclear receptors NR4A2 and NR4A3 in monocytes.

Perioperative Mortality and Periprosthetic Fracture: A Single-Center Experience of 857 Uncemented Hemiarthroplasties for Displaced Femoral Neck Fractures

BACKGROUND

Uncemented hemiarthroplasty (UHA) for displaced femoral neck fracture (FNF) is favored by some surgeons because of the reduced rate of perioperative mortality and operative time. However higher rates of intraoperative and postoperative periprosthetic fractures (PPFs) have been reported. The aim of the study was to review day-0, day-1, day-2, day-30, and one-year mortality as well as intraoperative and postoperative PPF after UHA for displaced FNF and compare this with cemented hemiarthroplasties (CHAs) performed. Secondary objectives were to assess whether femoral stem geometry and alignment were associated with PPF in UHA.

METHODS

A retrospective observational study was conducted of patients treated with a hemiarthroplasty for a displaced FNF over an eleven-year period. Radiographic analysis was conducted of femoral geometry and stem alignment.

RESULTS

Over the 11-year study period, 857 UHAs and 247 CHAs were performed. There were no on-table, day-0, day-1, or day-2 deaths in UHA. Intraoperative PPF occurred in 3.6% UHA and 2% CHA and postoperative PPF in 2.4% UHA and 4.8% CHA. Intraoperative PPF was not associated with increased mortality (P = .15), postoperative PPF, or all-cause revision in UHA. Valgus stem alignment was a risk factor for a postoperative PPF and additional surgery in UHA (P = .004).

CONCLUSION

UHA was associated with no perioperative deaths and a 30-day mortality rate of 5% in this series. It can be considered in patients with multiple medical comorbidities. Careful surgical planning and technique is important to optimize stem alignment particularly in Dorr C type femurs.

Intermediate to Long-Term Follow-up of Distal Femoral Replacements in the Treatment of Neoplastic Disease About the Knee

Background

Limb salvage procedures have become more prevalent in orthopedic oncology. Endoprostheses have been used successfully to reconstruct large skeletal deficits. The aim was to review intermediate to long-term follow-up of distal femoral replacements in the setting of neoplastic disease about the knee.

Methods

This was a single-center retrospective cohort study from 1997 to 2018 in a national referral center for oncology. The secondary objectives were to describe morbidity and mortality in this cohort. We recorded the modes of failure using Henderson classification system, complications, revisions, and all further operations.

Results

Seventy-two distal femoral replacements were performed. Osteosarcoma was the most common indication (55 patients). Other indications included chondrosarcoma (7 patients), giant cell tumor (5 patients), Ewing’s sarcoma (2 patients), metastatic spread (2 patients), and leiomyosarcoma (1 patient). One-year mortality was 1.38% with an overall mortality of 13.8%, at the end of the study period. The 1-year revision rate was 4.2%, 30.5% for 10 years, and 38.8% for more than 15 years. The overall implant survival rate was 63.8%. The most common reasons for failure included aseptic loosening (16.6%), infection (16.6%), and local recurrence (9.7%) with an amputation rate of 6.9% in the cohort.

Conclusion

Neoplastic disease of the lower limb is associated with significant morbidity. Aseptic loosening (16.6%) and infection (16.6%) were the most common reasons for failure in this cohort.

Establishing a Virtual Clinic for Developmental Dysplasia of the Hip: A Prospective Study

BACKGROUND

The aim was to describe the introduction and operation of a virtual developmental dysplasia of the hip (DDH) clinic. Our secondary objectives were to provide an overview of DDH referral reasons, treatment outcomes, and adverse events associated with it.

METHODS

A prospective observational study involving all patients referred to the virtual DDH clinic was conducted. The clinic consultant delivered with 2 DDH clinical nurse specialists (CNS). The outcomes following virtual review include further virtual review, CNS review, consultant review or discharge. Treatment options include surveillance, brace therapy, or surgery. Efficiency and cost analysis were assessed.

RESULTS

Over the 3.5-year study period, 1002 patients were reviewed, of which 743 (74.2%) were female. The median age at time of referral was 7 months, (interquartile range of 5 to 11) with a median time to treatment decision of 9 days. Median waiting times from referral to treatment decision was reduced by over 70%. There were 639 virtual reviews, 186 CNS reviews, and 144 consultant reviews. The direct discharge rate was 24%. One hundred one patients (10%) had dislocated or subluxed hips at initial visit while 26.3% had radiographically normal hips. Over the study period 704 face to face (F2F) visits were avoided. Cost reductions of €170 were achieved per patient, with €588,804 achieved in total. Eighteen parents (1.8%) opted for F2F instead of virtual review. There were no unscheduled rereferrals or recorded adverse events.

CONCLUSION

We report the outcomes of the first prospective virtual DDH clinic. This clinic has demonstrated efficiency and cost-effectiveness, without reported adverse outcomes to date. It is an option to provide consultant delivered DDH care, while reducing F2F consults.

LEVEL OF EVIDENCE

Level III.

Protein kinase D, ubiquitin and proteasome pathways are involved in adenosine receptor-stimulated NR4A expression in myeloid cells

Adenosine is a purine nucleoside pivotal for homeostasis in cells and tissues. Stimulation of the adenosine receptors (AR) has been shown to regulate the nuclear orphan receptor 4A (NR4A1-3) family, resulting in attenuation of hyper-inflammatory responses in myeloid cells. The NR4A1-3 orphan receptors are early immediate response genes and transcriptional regulators of cell and tissue homeostasis. The signal transduction and transcriptional mechanism(s) of how AR-stimulation promotes NR4A expression in myeloid cells is unknown and is the focus of this study. We confirm that adenosine and the stable analogue, 5'-N-Ethylcarboxamidoadenosine (NECA), enhance NR4A1-3 expression in THP-1 cells. Pharmacological approaches identified that protein kinase D (PKD) mediates AR-stimulated NR4A expression in myeloid cells and reveals no involvement of PKA nor PKC. The role of NF-κB, a principal regulator of NR4A expression in myeloid cells, was examined as a possible transcriptional regulator downstream of PKD. Utilising BAY11-7082 and MG-132, inhibitors of the respective ubiquitin and proteasome pathways essential for NF-κB activation, suggested a prospective role for NF-κB, or more specifically signalling via IKKα/β. However, biological interventional studies using overexpression of IκBα in myeloid cells and MEF cells lacking IKKα and IKKβ (IKKα/β^-/-) revealed the NF-κB pathway is not utilised in mediating AR-stimulated NR4A expression. Thus, this study contributes mechanistic insight into how AR signalling modulates the expression of NR4A receptors, pivotal regulators of inflammatory responses in myeloid cells.

The NR4A agonist, Cytosporone B, attenuates pro-inflammatory mediators in human colorectal cancer tissue ex vivo

Inflammation is a pivotal pathological factor in colorectal cancer (CRC) initiation and progression, and modulating this inflammatory state has the potential to ameliorate disease progression. NR4A receptors have emerged as key regulators of inflammatory pathways that are important in CRC. Here, we have examined the effect of NR4A agonist, Cytosporone B (CsnB), on colorectal tissue integrity and its effect on the inflammatory profile in CRC tissue ex vivo. Here, we demonstrate concentrations up 100 μM CsnB did not adversely affect tissue integrity as measured using transepithelial electrical resistance, histology and crypt height. Subsequently, we reveal through the use of a cytokine/chemokine array, ELISA and qRT-PCR analysis that multiple pro-inflammatory mediators were significantly increased in CRC tissue compared to control tissue, which were then attenuated with the addition of CsnB (such as IL-1β, IL-8 and TNFα). Lastly, stratification of the data revealed that CsnB especially alters the inflammatory profile of tumours derived from males who had not undergone chemoradiotherapy. Thus, this study demonstrates that NR4A agonist CsnB does not adversely affect colon tissue structure or functionality and can attenuate the pro-inflammatory state of human CRC tissue ex vivo.

Targeting NR4A Nuclear Receptors to Control Stromal Cell Inflammation, Metabolism, Angiogenesis, and Tumorigenesis

The NR4A1–NR4A3 (Nur77, Nurr1, and Nor-1) subfamily of nuclear receptors is a group of immediate early genes induced by a pleiotropy of stimuli including peptide hormones, growth factors, cytokines, inflammatory, and physiological stimuli, and cellular stress. NR4A receptors function as potent sensors of changes in the cellular microenvironment to control physiological and pathological processes through genomic and non-genomic actions. NR4A receptors control metabolism and cardiovascular and neurological functions and mediate immune cell homeostasis in inflammation and cancer. This receptor subfamily is increasingly recognized as an important molecular connection between chronic inflammation, altered immune cell responses, and cancer development. In this review, we examine how transcriptome analysis identified NR4A1/NR4A2 receptors as transcriptional regulators in mesenchymal stromal cell (MSC) migration, cell cycle progression, and cytokine production to control local immune responses. In chronic inflammatory conditions, such as rheumatoid arthritis, NR4A receptors have been shown to modify the activity of MSC and fibroblast-like stromal cells to regulate synovial tissue hyperplasia, pathological angiogenesis, and cartilage turnover in vivo. Additionally, as NR4A1 has been observed as a major transcriptional regulator in tumor–stromal communication controlling tumorigenesis, we discuss how advances in the pharmacological control of these receptors lead to important new mechanistic insights into understanding the role of the tumor microenvironment in health and disease.

Perioperative Mortality After Cemented or Uncemented Hemiarthroplasty for Displaced Femoral Neck Fractures-A Systematic Review and Meta-analysis

BACKGROUND

Debate surrounds the use of cemented or uncemented prostheses for the treatment of displaced femoral neck fractures (FNF). Many guidelines recommend the use of the cemented hemiarthroplasty (CHA). Proponents of CHA point out the increased re-operation rate while proponents of uncemented hemiarthroplasty (HA) highlight the increased mortality rate in the perioperative period. The aim of this study was to systematically review the literature to evaluate perioperative mortality after HA for displaced FNFs.

METHODS

A systematic review and meta-analysis was performed of MEDLINE, Cochrane Library, and Embase databases evaluating perioperative mortality after HA for displaced FNFs. Randomized control trials and observational studies were included comparing current-generation stem designs. A meta-analysis was performed on studies that directly compared the different modes of fixation.

RESULTS

Twenty-two studies were included (seven randomized control trials and 15 observational studies), with a total of 183,167 HAs for treatment of a displaced FNF. Fourteen studies were included in the meta-analysis. There was a higher cumulative odds of death within the first 48 hours in those with CHA compared with uncemented HA (OR: 1.64; 95% CI: 1.35, 2.00; P ≤ .01). No difference was found in mortality at 7 days, 30 days, and one year.

CONCLUSION

CHA is associated with an increased mortality rate within the first two days of surgery with no difference at 7 days, 30 days, and one year. Surgeons should consider tailoring their stem choice based on the physiological status of the patient when planning HA for FNFs. Techniques to reduce the risk of bone cement implantation syndrome should be used.

Virtual geriatric clinics and the COVID-19 catalyst: a rapid review

Background

During the current COVID-19 health crisis virtual geriatric clinics have become increasingly utilised to complete outpatient consultations, although concerns exist about feasibility of such virtual consultations for older people. The aim of this rapid review is to describe the satisfaction, clinic productivity, clinical benefit, and costs associated with the virtual geriatric clinic model of care.

Methods

A rapid review of PubMed, MEDLINE and CINAHL databases was conducted up to April 2020. Two independent reviewers extracted the information. Four subdomains were focused on: satisfaction with the virtual geriatric clinic, clinic productivity, clinical benefit to patients, costs and any challenges associated with the virtual clinic process.

Results

Nine studies with 975 patients met our inclusion criteria. All were observational studies. Seven studies reported patients were satisfied with the virtual geriatric clinic model of care. Productivity outcomes included reports of cost-effectiveness, savings on transport, and improved waiting list metrics. Clinical benefits included successful polypharmacy reviews, and reductions in acute hospitalisation rates. Varying challenges were reported for both clinicians and patients in eight of the nine studies. Hearing impairments and difficulty with technology added to anxieties experienced by patients. Physicians missed the added value of a thorough physical examination and had concerns about confidentiality.

Conclusion

Virtual geriatric clinics demonstrate evidence of productivity, benefit to patients, cost effectiveness and patient satisfaction with the treatment provided. In the current suboptimal pandemic climate, virtual geriatric clinics may allow Geriatricians to continue to provide an outpatient service, despite the encountered inherent challenges.

Key Service Improvements After the Introduction of an Integrated Orthogeriatric Service

Introduction:

Models of orthogeriatric care have been shown to improve functional outcomes for patients after hip fractures and can improve compliance with best practice guidelines for hip fracture care.

Methods:

We evaluated improvements to key performance indicators in hip fracture care after implementation of a formal orthogeriatric service. Compliance with Irish Hip Fracture standards of care was reviewed, and additional outcomes such as length of stay, access to rehabilitation, and discharge destination were evaluated.

Results:

Improvements were observed in all of the hip fracture standards of care. Mean length of stay decreased from 19 to 15.5 days (mean difference 3.5 days; P < .05). A higher proportion of patients were admitted to rehabilitation (16.7% vs 7.9%, P < .05), and this happened in a timelier fashion (17.8 vs 24.8 days, P < .05). We found that less patients required convalescence post-hip fracture.

Discussion:

A standardized approach to integrated post-hip fracture care with orthogeriatrics has improved standards of care for patients.

Conclusion:

Introduction of orthogeriatric services has resulted in meaningful improvements in clinical outcomes for older people with hip fractures.

Does Google™ Have the Answers? The Internet-based Information on Pelvic and Acetabular Fractures

Introduction

The aim of this study is to assess the readability and reliability of internet-based information on pelvic and acetabular fractures.

Methods

The three most popular English-based internet search engines are Google, Yahoo, and Bing. Quality was assessed using the DISCERN tool, the Journal of the American Medical Association tool, and the presence of the Health on the Net Code (HONcode) seal. Readability was assessed using a combination of the Flesch Reading Ease Score and the Flesch-Kincaid grade level. Inclusion criteria included English language websites with the relevant search terms. We excluded videos, YouTube links, or sponsored advertisements. Search terms included acetabular fracture/fractured acetabulum and pelvic fracture/fractured pelvis. The top 25 websites in each search engine were reviewed. The searches for acetabular fractures and pelvic fractures generated 75 websites in total. Duplicates were excluded.

Results

The search for acetabular fracture revealed 36 discrete websites among the three search engines, and the search for pelvic fractures revealed 45 websites. Overall, the average reading grade was 9.7 for acetabular websites and 13.6 for pelvis websites. The quality of the websites was poor across all key performance indicators studied.

Conclusion

Physicians should be aware of the quality of medical information available to patients via internet searches because physicians should play a central role in the navigation of poor quality information to help direct patient-centered care.

A prospective evaluation of bone marrow aspirate concentrate and microfracture in the treatment of osteochondral lesions of the talus

BACKGROUND

The term osteochondral lesion (OCL) refers to a defect involving the chondral surface and or subchondral bone. These lesions are associated with ankle injuries with bony and soft tissue and cause pain, decreased range of motion, swelling and impact adversely on quality of life. To date the standard treatment has been isolated microfracture (BMS). The aim of this study was to compare the outcomes of BMS alone to BMS augmented with bone marrow aspirate concentrate (BMAC) in the treatment of ankle OCLs.

METHODS

This study was a prospective cohort study carried out from 2010-2015 in a single surgeon's practice. Patients from 2010-2012 were treated with microfracture alone while patients from 2013-2015 were treated with micro fracture augmented with bone marrow aspirate concentrate and fibrin glue. Self-reported patient outcome measures were measured. Complications, revision rates, and visual analogue pain scores were compared.

RESULTS

101 patients were included in the study. 52 patients were in the microfracture group while 49 patients were in the microfracture/BMAC group. The minimum follow-up for both groups was 36 months. Both groups had a statistically significant improvement in pain scores, quality of life scores, participation in sport and activities of daily living. The revision rate was 28.8% in the microfracture group versus 12.2% in the microfracture/BMAC group, which was statistically significant, p=0.0145. The majority of the lesions were less than 1.5cm² in diameter in both cohorts.

CONCLUSIONS

Microfracture and bone marrow aspirate concentrate appears to be a safe and effective treatment option for osteochondral lesions of the talus. The addition of bone marrow aspirate concentrate does not result in any increase in ankle or donor site morbidity. It is a well-tolerated therapy which decreases revision rates for treatment of the osteochondral lesions when compared to microfracture alone.

LEVEL OF EVIDENCE

Level III.

The burden of hardware removal in ankle fractures: How common is it, why do we do it and what is the cost? A ten-year review

BACKGROUND

Ankle fractures account for 9% of all fractures and 40% require surgical management. The ankle is the most common site of hardware removal. The purpose of our study was to investigate the incidence, indication and economic cost associated with removal of hardware from the ankle.

METHODS

We conducted a ten-year retrospective review of 1482 patients treated by open reduction internal fixation for an unstable ankle fracture. Skeletally immature patients were excluded. Data collected was cross referenced from patient medical records, the radiological and electronic patient database. The casemix and hospital inpatient enquiry system (HIPE) were used to calculate costs.

RESULTS

The mean age was 39.9 years with 53.6% male. 185 patients (12.5%) underwent hardware removal with unplanned removal performed in 6% of cases. The average cost of removal was €1113.

CONCLUSION

Removal of hardware continues to be a common operation with significant costs to all involved. More than one in 10 patients underwent future removal of hardware.

LEVEL OF EVIDENCE

Level 3.

Breaking Bad: A Comparative Descriptive Analysis of Periprosthetic Fractures Around Cemented and Uncemented Femoral Stems

BACKGROUND

Periprosthetic fractures are most commonly classified according to the Vancouver classification system and more recently the Unified Classification System. The aim of this study is to provide a descriptive analysis of fracture patterns in femoral periprosthetic fractures (PPFs) by femoral stem fixation.

METHODS

A retrospective observational study of all femoral PPFs over a 10-year period at our institution was conducted. Presenting radiographs were examined to assess the fracture pattern.

RESULTS

Over the 10-year period, 138 femoral PPFs that underwent operative treatment were examined. Mean age of patients was 78 years with 45.7% male and median American Society of Anaesthesiologists grade 3. The femoral stem fixation was cemented in 83 patients and uncemented in 55 patients. Uncemented femoral stems most commonly caused a simple oblique fracture pattern (69.1%) with a more comminuted pattern seen in cemented fixation (59%).

CONCLUSION

Fracture patterns differ according to femoral stem fixation. A simple "sickle-like" oblique fracture pattern was more commonly seen in uncemented stems while cemented tapered stems resulted in a comminuted "axe splitting" pattern.

A novel approach using 3-D printing in the Irish National Centre for pelvic and acetabular surgery

BACKGROUND

Complex pelvic fractures present the orthopaedic surgeon with many challenges. 3-D printed models may provide assistance in pre-operative planning, may lead to improvements in intra-operative (i) decision making and (ii) efficiencies (time reduction, blood loss reduction, screening reduction) and may result in improvements in post-operative outcomes (fracture reduction & quality of life). The models also provide hands-on opportunities for orthopaedic trainees and patients. This may result in improvements in (i) education/training regarding the management of pelvic and acetabular fractures for orthopaedic trainees and (ii) improvements in patient consenting and overall patient satisfaction.

DESIGN

Single-centre, two orthopaedic surgeons (pelvic and acetabular fellowship trained), prospective observational study. Twenty patients with acute displaced pelvic/acetabular fracture(s); ten 3-D-printed pelvis and ten non-printed cases for comparison. The comparison cohorts were matched for fracture classification, sex and age.

OUTCOME MEASURES

Classification assistance, intra-operative time, estimated blood loss, screening amount, post-operative reduction and infection, EQ-5D-5L, teaching/educational assistance and pre-operative counselling.

RESULTS

The models provided more information regarding fracture pattern, however, this did not result in change of CT-planned approach/procedure or patient outcomes. The models scored highly on surgeon's questionnaire. The models were found to have a positive impact on trainee education and patient consenting/counselling. With regard to objective comparisons, there was no significant improvements in time-to-surgery, intra-operative time, estimated blood loss, screening amount, fracture reduction or infection rate. There was no significant difference in quality of life questionnaire ~ 12 months post-surgery (statistical tests used; Cohen's effect size and Fisher's exact test).

CONCLUSIONS

Whilst the authors recognize the positive subjective findings with respect to the use of 3-D printing in pelvic and acetabular trauma in our National Centre, objective findings were lacking.

A growing challenge: The rise of femoral periprosthetic fractures - An 11-year observational study

INTRODUCTION

The demand for joint arthroplasty has risen as our elderly population increases and ages. With this so to has the number of patients suffering periprosthetic fractures (PPF). The aim of our study was to quantify the burden of PPF and provide an up to date reference of the epidemiology of PPF in Ireland. We also sought to assess length of stay (LOS), resource utilisation and mortality associated with this cohort of patients.

METHODS

An eleven-year retrospective observational study was conducted of a consecutive series of patients treated for a femoral PPF. Costs were obtained from activity based tariffs provided by the hospital inpatient enquiry system and mortality was confirmed using the national death events publication system.

RESULTS

Over the 11-year study period 174 procedures for a femoral PPF were performed. Mean age of patients was 77.6 years (SD 11.1 years) with 44.7% male. Median ASA grade was 3 (range 1-4) and mean LOS was 19 days. There was a 700% increase in patients undergoing surgery for a PPF over the study period. The mean cost of care was €24,413 in 2017. Thirty-day mortality was 2.9% while one-year mortality was 12.4%.

CONCLUSIONS

PPF occur in an elderly comorbid cohort of patients. Care of these patients now makes up a considerable part of the orthopaedic workload and consumes a significant portion of healthcare resources. Patients should be treated in tertiary referral centres with surgeons skilled in their management. Better access to rehabilitation is needed.

Where does Pelvic and Acetabular Fracture Treatment fit into the Newly Proposed Major Trauma Model in Ireland?

Aim To provide the most up to date reference of referral patterns for pelvis and acetabular (PA) fractures in Ireland and discuss where services should ideally be located. Methods A retrospective review was conducted of all referrals to the national referral centre for PA fractures in Ireland for 2016 and 2017. Results Over the two-year study period 456 referrals were made. Mean age of patients was 53 years, 62.9% were male. Management was conservative in 60.7%, operative in 38.2% while 1.1% died prior to transfer. Nearly half of fractures (47.8%) were due to falls with 38.6% due to road trauma. Referrals from the proposed central trauma network accounted for 76.1% of referrals. Median length of stay was 7 days. Average cost of operative treatment was €11,774. Conclusions PA trauma is associated with significant morbidity and costs to both patients and society. Consideration needs to be given to where best to place PA services to ensure the highest quality care in this cohort of patients

Subcellular Localization of NR4A2 Orphan Nuclear Receptor Expression in Human and Mouse Synovial Joint Tissue

NR4A1-3 receptors are required in inflammatory disease initiation and progression, where they function as early response regulators, controlling the extent of the inflammatory response and promoting inflammatory resolution. NR4A receptor activity controls inflammatory processes in several diseases characterized by chronic inflammation including rheumatoid arthritis (RA) and atherosclerosis. Studies indicate that cell-type and cellular microenvironment can alter NR4A1-3 receptor activity and influence their biological roles. Thus, the study of appropriate in vivo models of inflammatory disease is important to ascertain their cell- and tissue-specific functional roles. Here we describe immunohistochemical approaches optimized to study the expression patterns of NR4A nuclear receptors in inflamed synovium tissues obtained from patients diagnosed with RA and mouse models of inflammatory joint disease.

A growing problem: cycling referrals to the National Centre for Pelvic and Acetabular Fracture Management in Ireland

BACKGROUND

Popularity in cycling continues to grow. In Ireland, in the last 5 years, 42% more people now use it to travel to work. This has been mirrored by a rise in cycling-related trauma and deaths. The popularity amongst men has led to the term middle-aged men in Lycra (MAMIL) being coined.

AIMS

The purpose of our study was to quantify cycling-related pelvic and acetabular fracture referrals in Ireland and determine injury patterns, cost and functional outcomes following these injuries.

METHODS

A retrospective cohort study was conducted of all referrals to our institution, the National Centre for Pelvis and Acetabular Fracture Management, in 2016 and 2017. Demographic, mechanism of injury, concomitant trauma and treatment data were analysed. Patients were contacted to assess return to work, sport and quality of life (EQ-5D-3L).

RESULTS

Cycling injury referrals increased by 90% between 2016 and 2017 with a greater number of cycling than motorbike injury referrals. Twenty-nine patients sustained a pelvic and acetabular (PA) injury while cycling. The mean patient age was 51.7 years of which 86.2% were male with 41% suffering a concomitant injury. Fourteen patients (48.3%) required surgery of which 60% have returned to cycling. Mean cost of treatment was €11,757. The median EQVAS was 80.

CONCLUSIONS

The rise in popularity of cycling has been mirrored by an increase in PA injuries and deaths. These injuries are associated with significant costs to the patient, hospital and society. Greater investment in safety and awareness is needed to protect this vulnerable group.

Differential regulation of transcription by the NURR1/NUR77 subfamily of nuclear transcription factors

NURR1 is an orphan member of the nuclear receptor superfamily of transcription factors that shares close sequence homology to the orphan nuclear receptor and immediate early gene product NUR77(NGF1 beta). The physiological role of NURR1 has not been established in mammalian cells. However, the observation that NURR1 and NUR77 interact with at least one common enhancer element (AAAAGGTCA), together with their partly overlapping but differential expression patterns in mammalian tissues, suggests that these proteins may have both shared and independent transcription regulatory functions. To identify potential target genes that may be regulated by NURR1, we analyzed its DNA binding properties to potential cis-acting enhancer elements. Using point mutagenesis of the AAAAGGTCA motif, we have identified three additional sequences that bind specifically to both NURR1 and NUR77, one of which serves as a functional enhancer element. Comparative analysis of the transcription regulatory properties of NURR1 and NUR77 indicates that the proteins can display opposing transregulatory activities that are influenced by the specific cis-acting sequences to which they bind. Our results indicate that the transcriptional responses of specific target genes to the NURR1/NUR77 subfamily may be differentially regulated by the relative cellular levels of NURR1 and NUR77 and influenced by the specific enhancer sequences that mediate their activity. Finally, we have identified several potential target genes of neuronal and neuroendocrine origin whose promoters contain this element.

Osteochondral lesions of the ankle: The current evidence supporting scaffold-based techniques and biological adjuncts

BACKGROUND

Talar osteochondral lesions are more common than has been previously recognized. Optimal treatment remains unclear and the subject of much debate in the literature. Although reparative techniques such as microfracture have produced initial good results and remain the gold standard in the management of these lesions, the literature is deficient in long-term data. Recently, techniques focused on enhancing the local biological environment have been developed which have demonstrated promising outcomes.

METHODS

We reviewed the available evidence concerning scaffold-based techniques and biological adjuncts in the management of talar osteochondral lesions published in the English language on PubMed.

RESULTS

An update is provided on the current evidence concerning the role of biological adjuncts in the management of osteochondral lesions of the talus.

CONCLUSIONS

There has been an explosion of interest among the orthopaedic community in the role of biologics in the management of complex talar osteochondral lesions. A number of exciting new techniques have been developed which show promise. Robust randomized control trials are required to identify the optimal surgical strategy.

Bone Marrow Aspirate Concentrate and Microfracture Technique for Talar Osteochondral Lesions of the Ankle

Osteochondral lesions of the talus refer to a chondral or subchondral defect of the articular cartilage and potentially the underlying bone. Ankle sprains are an extremely common injury; approximately 27,000 ankle sprains occur per day in America. Fifty percent of these can lead to a cartilage injury to the ankle. There has been a high quoted rate of failure with conservative measures of up to 45% in some series. Surgical options are largely broken down into 2 groups, namely, reparative or regenerative treatments. The reparative techniques include debridement and bone marrow stimulation techniques such as microdrilling and microfracture. Regenerative techniques include autologous osteochondral transplants. However, there are disadvantages in terms of donor site morbidity and the development of subchondral bone cysts over time. The aim of this video is to demonstrate a technique for microfracture and augmentation with bone marrow aspirate concentration and Tisseel fibrin glue. This video details the indications for performing microfracture, the indications for using bone marrow stimulation techniques, and the contraindications. Patient positioning, setup, preparation of the lesion, harvesting of the bone marrow aspirate concentrate, and application of the bone marrow aspirate are detailed.

Spinal Metastatic Disease: A Review of the Role of the Multidisciplinary Team

Historically, a simple approach centered on palliation was applicable to the majority of patients with metastatic spinal disease. With advances in diagnosis and treatment, a more complicated algorithm has devolved requiring a multidisciplinary approach with institutional commitment and support. We performed a database review including pertinent articles exploring the multidisciplinary management of spinal metastatic disease. The wide variation in clinical presentation and tumor response to treatment necessitates a multidisciplinary approach that integrates the diagnosis and treatment of the cancer, symptom management, and rehabilitation for optimal care of patients with spinal metastases. Advances in the field of radiology have led to earlier and more focused diagnosis of spinal metastasis and acts to guide therapy. Advances in surgical techniques, neurophysiologic monitoring, and anesthetic expertise have allowed surgeons to perform more extensive procedures leading to improved outcomes and reduced morbidity. Radiation oncology input that is essential as external beam radiation therapy can provide significant pain relief. Non-operative measures may include bisphosphonate infusions, management of complications (e.g. hypercalcemia of malignancy), monoclonal antibody infusions, and chemotherapy if indicated in the treatment of the primary malignancy. Input from psychology services is necessary to address the biopsychosocial ramifications of spinal metastasis. Allied health professionals in the form of physiotherapists, social workers, and dieticians also contribute in maximizing patients' quality of life and well-being.

NR4A Receptors Differentially Regulate NF-κB Signaling in Myeloid Cells

Dysregulation of inflammatory responses is a hallmark of multiple diseases such as atherosclerosis and rheumatoid arthritis. As constitutively active transcription factors, NR4A nuclear receptors function to control the magnitude of inflammatory responses and in chronic inflammatory disease can be protective or pathogenic. Within this study, we demonstrate that TLR4 stimulation using the endotoxin lipopolysaccharide (LPS) rapidly enhances NR4A1–3 expression in human and murine, primary and immortalized myeloid cells with concomitant gene transcription and protein secretion of MIP-3α, a central chemokine implicated in numerous pathologies. Deficiency of NR4A2 and NR4A3 in human and murine myeloid cells reveals that both receptors function as positive regulators of enhanced MIP-3α expression. In contrast, within the same cell types and conditions, altered NR4A activity leads to suppression of LPS-induced MCP-1 gene and protein expression. An equivalent pattern of inflammatory gene regulation is replicated in TNFα-treated myeloid cells. We show that NF-κB is the critical regulator of NR4A1–3, MIP-3α, and MCP-1 during TLR4 stimulation in myeloid cells and highlight a parallel mechanism whereby NR4A activity can repress or enhance NF-κB target gene expression simultaneously. Mechanistic insight reveals that NR4A2 does not require DNA-binding capacity in order to enhance or repress NF-κB target gene expression simultaneously and establishes a role for NF-κB family member Relb as a novel NR4A target gene involved in the positive regulation of MIP-3α. Thus, our data reveal a dynamic role for NR4A receptors concurrently enhancing and repressing NF-κB activity in myeloid cells leading to altered transcription of key inflammatory mediators.

Prospective Evaluation of Intra-Articular Sodium Hyaluronate Injection in the Ankle

Viscosupplementation by injection of hyaluronic acid into the ankle can be used to provide pain relief and to delay the need for surgery in patients with osteoarthritis of the ankle. In the present investigation, we prospectively evaluated 50 consecutive patients (25 males and 25 females) undergoing a 3-injection protocol of sodium hyaluronate viscosupplementation in the ankle from January 2014 to January 2015. The Foot and Ankle Outcomes Score was used to compare the patients' pre- and post-treatment opinions about their ankle problems. The mean pretreatment Foot and Ankle Outcomes Score was 48 ± 6.3 (range 25 to 84) and the 6-month post-treatment score was 78 ± 5.8 (range 48 to 100). This difference was statistically significant (p = .003). From our findings in the present prospective cohort study, we have concluded that intra-articular injection of sodium hyaluronate viscosupplementation is a useful conservative therapy for osteoarthritis of the ankle.

Single Oblique Incision for Simultaneous Open Reduction and Internal Fixation of the Posterior Malleolus and Anterior Syndesmosis

Several surgical approaches to the posterior malleolus have been described. However, these approaches may make it difficult for fixation of associated lateral malleolar and anterior syndesmotic fractures. A single incision approach is described that allows safe access to the posterior malleolus while also facilitating access to the lateral malleolus and anterior syndesmosis.

Adenosine Modulates NR4A Orphan Nuclear Receptors To Attenuate Hyperinflammatory Responses in Monocytic Cells

Adenosine receptor-mediated regulation of monocyte/macrophage inflammatory responses is critical in the maintenance of tissue homeostasis. In this study, we reveal that adenosine potently modulates the expression of NR4A1, 2, and 3 orphan nuclear receptors in myeloid cells, and this modulation is primarily through the adenosine A2a receptor subtype. We demonstrate that A2a receptor activation of NR4A1-3 receptor synthesis is further enhanced in TLR4-stimulated monocytes. After TLR4 stimulation, NR4A receptor-depleted monocyte/macrophage cells display significantly altered expression of cell-surface markers and produce increased inflammatory cytokine and chemokine secretion rendering the cells an enhanced proinflammatory phenotype. Exposure of TLR4 or TNF-α-stimulated monocytes to adenosine analogs directs changes in the expression of MIP-3α and IL-23p19, with NR4A2 depletion leading to significantly enhanced expression of these factors. Furthermore, we establish that nuclear levels of NF-κB/p65 are increased in TLR/adenosine-stimulated NR4A2-depleted cells. We show that, after TLR/adenosine receptor stimulation, NR4A2 depletion promotes significant binding of NF-κB/p65 to a κB consensus binding motif within the MIP-3α proximal promoter leading to increased protein secretion, confirming a pivotal role for NF-κB activity in controlling cellular responses and gene expression outcomes in response to these mediators. Thus, these data demonstrate that during an inflammatory response, adenosine modulation of NR4A receptor activity acts to limit NF-κB-mediated effects and that loss of NR4A2 expression leads to enhanced NF-κB activity and hyperinflammatory responses in myeloid cells.

Tumor necrosis factor inhibition modulates thrombospondin-1 expression in human inflammatory joint disease through altered NR4A2 activity

We examined thrombospondin-1 (THBS1, alias TSP-1) expression in human synovial tissue (ST) during the resolution phase of chronic inflammation and elucidated its transcriptional regulation by the orphan receptor 4A2 (NR4A2). In vivo, rheumatoid arthritis (RA) serum and ST revealed altered expression levels and tissue distribution of TSP-1. After anti-tumor necrosis factor therapy, a reciprocal relationship between TSP-1 and NR4A2 expression levels was measured in patients with clinical and ST responses to biological treatment. In vitro, primary RA fibroblast-like synoviocytes (FLSs) expressed minimal TSP-1 mRNA levels with high transcript levels of NR4A2, vascular endothelial growth factor (VEGF), and IL-8 measured. Hypoxic modulation of RA FLSs resulted in inverse expression levels of TSP-1 compared with NR4A2, IL-8, and VEGF. Ectopic NR4A2 expression led to reduced TSP-1 mRNA and protein levels with concomitant increases in proangiogenic mediators. NR4A2 transcriptional activity, independent of DNA binding, repressed the hTSP-1 promoter leading to reduced mRNA and protein release in immortalized K4IM FLSs. Bioinformatic and deletion studies identified a 5' region of the TSP-1 promoter repressed by NR4A2 and proangiogenic transcription factors, including NF-κB and Ets1/2. Stable depletion of NR4A2 levels resulted in a shift in the TSP-1/VEGF expression ratio. Thus, modulation of TSP-1 expression is achieved through anti-tumor necrosis factor therapy effects on specific transcriptional networks, suggesting that enhanced TSP-1 expression may help restore tissue homeostasis during resolution of inflammation.

An intra-articular salmon calcitonin-based nanocomplex reduces experimental inflammatory arthritis

Prolonged inappropriate inflammatory responses contribute to the pathogenesis of rheumatoid arthritis (RA) and to aspects of osteoarthritis (OA). The orphan nuclear receptor, NR4A2, is a key regulator and potential biomarker for inflammation and represents a potentially valuable therapeutic target. Both salmon calcitonin (sCT) and hyaluronic acid (HA) attenuated activated mRNA expression of NR4A1, NR4A2, NR4A3, and matrix metalloproteinases (MMPs) 1, 3 and 13 in three human cell lines: SW1353 chondrocytes, U937 and THP-1 monocytes. Ad-mixtures of sCT and HA further down-regulated expression of NR4A2 compared to either agent alone at specific concentrations, hence the rationale for their formulation in nanocomplexes (NPs) using chitosan. The sCT released from NP stimulated cAMP production in human T47D breast cancer cells expressing sCT receptors. When NP were injected by the intra-articular (I.A.) route to the mouse knee during on-going inflammatory arthritis of the K/BxN serum transfer model, joint inflammation was reduced together with NR4A2 expression, and local bone architecture was preserved. These data highlight remarkable anti-inflammatory effects of sCT and HA at the level of reducing NR4A2 mRNA expression in vitro. Combining them in NP elicits anti-arthritic effects in vivo following I.A. delivery.

Histamine contributes to increased RANKL to osteoprotegerin ratio through altered nuclear receptor 4A activity in human chondrocytes

OBJECTIVE

To elucidate histamine receptor-mediated signaling pathways, transcriptional events, and target gene expression in human cartilage.

METHODS

Histamine modulation of cartilage destruction was assessed by Safranin O staining and proteoglycan release. H(1) , H(2) , H(3) , and H(4) histamine receptor-dependent regulation of transcription factors (nuclear receptor 4A1 [NR4A1], NR4A2, and NR4A3), RANKL, and osteoprotegerin (OPG) messenger RNA (mRNA) levels were measured in primary and SW-1353 chondrocyte cells using quantitative polymerase chain reaction and selective histamine receptor antagonists. Soluble RANKL and OPG protein levels were determined using enzyme-linked immunosorbent assays. NR4A protein levels and transactivity were evaluated by Western blot analysis, immunocytochemistry, and luciferase reporter assays. Stable depletion of NR4A1-3 was achieved by lentiviral transduction of NR4A short hairpin RNA.

RESULTS

Primary human chondrocyte cells expressed differential steady-state levels of H(1) -H(4) histamine receptor mRNA. In combination with tumor necrosis factor α, histamine significantly promoted cartilage proteoglycan depletion and release. Histamine modulated the expression of NR4A1-3 orphan receptors in primary and immortalized human chondrocyte cells in a time- and concentration-dependent manner. Histamine selectively signaled through H(1) and H(2) histamine receptors in chondrocytes to modulate RANKL and NR4A2 expression. The temporal effects of histamine on NR4A2 gene transcription were reduced in cells pretreated with inhibitors directed against protein kinase A, MAPK, and NF-κB signaling pathways. Histamine modulated the expression of RANKL with modest effects on OPG levels, leading to increased RANKL:OPG mRNA and protein ratios. Stable knockdown of NR4A1-3 expression resulted in reduced endogenous OPG levels and the loss of histamine-dependent regulation of RANKL expression.

CONCLUSION

Our findings indicate that histamine, via H(1) and H(2) histamine receptors, contributes to joint disease by enhancing the ratio of RANKL to OPG expression through altered NR4A activity in human chondrocyte cells.

Orphan nuclear receptor NR4A2 induces synoviocyte proliferation, invasion, and matrix metalloproteinase 13 transcription

OBJECTIVE

To address the role of the nuclear receptor 4A (NR4A) family of orphan nuclear receptors in synoviocyte transformation, hyperplasia, and regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in models of inflammatory arthritis.

METHODS

NR4A messenger RNA levels in synovial tissue and primary synoviocytes were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR). NR4A2 was stably overexpressed in normal synoviocytes, and cell proliferation, survival, anchorage-independent growth, migration, and invasion were monitored in vitro. MMP and TIMP expression levels were analyzed by quantitative RT-PCR, and MMP-13 promoter activity was measured using reporter assays. Stable depletion of endogenous NR4A levels was achieved by lentiviral transduction of NR4A short hairpin RNA (shRNA), and the effects on proliferation, migration, and MMP-13 expression were analyzed.

RESULTS

NR4A2 was expressed at elevated levels in normal, OA, and RA synovial tissue and in primary RA synoviocytes. Tumor necrosis factor α (TNFα) rapidly and selectively induced expression of NR4A2 in synoviocytes. Ectopic expression of NR4A2 in normal synoviocytes significantly increased proliferation and survival, promoted anchorage-independent growth, and induced migration and invasion. MMP-13 gene expression was synergistically induced by NR4A2 and TNFα, while expression of TIMP-2 was antagonized. NR4A2 directly transactivated the proximal MMP-13 promoter, and a point mutation in the DNA binding domain of NR4A2 abolished transcriptional activation. Depletion of endogenous NR4A receptors with shRNA reduced synoviocyte proliferation, migration, and MMP-13 expression.

CONCLUSION

The orphan nuclear receptor NR4A2 is a downstream mediator of TNFα signaling in synovial tissue. NR4A2 transcriptional activity contributes to the hyperplastic and invasive phenotype of synoviocytes that leads to cartilage destruction, suggesting that this receptor may show promise as a therapeutic target in inflammatory arthritis.

Molecular pathways: the role of NR4A orphan nuclear receptors in cancer

Nuclear receptors are of integral importance in carcinogenesis. Manipulation of classic ligand-activated nuclear receptors, such as estrogen receptor blockade in breast cancer, is an important established cancer therapy. Orphan nuclear receptors, such as nuclear family 4 subgroup A (NR4A) receptors, have no known natural ligand(s). These elusive receptors are increasingly recognized as molecular switches in cell survival and a molecular link between inflammation and cancer. NR4A receptors act as transcription factors, altering expression of downstream genes in apoptosis (Fas-ligand, TRAIL), proliferation, DNA repair, metabolism, cell migration, inflammation (interleukin-8), and angiogenesis (VEGF). NR4A receptors are modulated by multiple cell-signaling pathways, including protein kinase A/CREB, NF-κB, phosphoinositide 3-kinase/AKT, c-jun-NH(2)-kinase, Wnt, and mitogen-activated protein kinase pathways. NR4A receptor effects are context and tissue specific, influenced by their levels of expression, posttranslational modification, and interaction with other transcription factors (RXR, PPAR-Υ). The subcellular location of NR4A "nuclear receptors" is also important functionally; novel roles have been described in the cytoplasm where NR4A proteins act both indirectly and directly on the mitochondria to promote apoptosis via Bcl-2. NR4A receptors are implicated in a wide variety of malignancies, including breast, lung, colon, bladder, and prostate cancer; glioblastoma multiforme; sarcoma; and acute and/or chronic myeloid leukemia. NR4A receptors modulate response to conventional chemotherapy and represent an exciting frontier for chemotherapeutic intervention, as novel agents targeting NR4A receptors have now been developed. This review provides a concise clinical overview of current knowledge of NR4A signaling in cancer and the potential for therapeutic manipulation.

Identification of NURR1 as a mediator of MIF signaling during chronic arthritis: effects on glucocorticoid-induced MKP1

Elucidation of factors regulating glucocorticoid (GC) sensitivity is required for the development of "steroid-sparing" therapies for chronic inflammatory diseases, including rheumatoid arthritis (RA). Accumulating evidence suggests that macrophage migration inhibitory factor (MIF) counterregulates the GC-induction of anti-inflammatory mediators, including mitogen-activated protein kinase phosphatase 1 (MKP1), a critical mitogen-activated protein kinase signaling inhibitor. This observation has yet to be extended to human disease; the molecular mechanisms remain unknown. We investigated NURR1, a GC-responsive transcription factor overexpressed in RA, as a MIF signaling target. We reveal abrogation by recombinant MIF (rMIF) of GC-induced MKP1 expression in RA fibroblast-like synoviocytes (FLS). rMIF enhanced NURR1 expression, artificial NBRE (orphan receptor DNA-binding site) reporter transactivation, and reversed GC-inhibition of NURR1. NURR1 expression was reduced during experimental arthritis in MIF-/- synovium, and silencing MIF reduced RA FLS NURR1 mRNA. Consistent with NBRE identification on the MKP1 gene, MKP1 mRNA was reduced in FLS that ectopically express NURR1, and silencing NURR1 enhanced MKP1 mRNA in RA FLS. rMIF enhanced NBRE binding on the MKP1 gene, and the absence of the NBRE prevented NURR1-repressive effects on basal and GC-induced MKP1 transactivation. This study defines NURR1 as a novel MIF target in chronic inflammation and demonstrates a role for NURR1 in regulating the anti-inflammatory mediator, MKP1. We propose a MIF-NURR1 signaling axis as a regulator of the GC sensitivity of MKP1.

Identification of NURR1 as a mediator of MIF signaling during chronic arthritis: effects on glucocorticoid-induced MKP1

Elucidation of factors regulating glucocorticoid (GC) sensitivity is required for the development of "steroid-sparing" therapies for chronic inflammatory diseases, including rheumatoid arthritis (RA). Accumulating evidence suggests that macrophage migration inhibitory factor (MIF) counterregulates the GC-induction of anti-inflammatory mediators, including mitogen-activated protein kinase phosphatase 1 (MKP1), a critical mitogen-activated protein kinase signaling inhibitor. This observation has yet to be extended to human disease; the molecular mechanisms remain unknown. We investigated NURR1, a GC-responsive transcription factor overexpressed in RA, as a MIF signaling target. We reveal abrogation by recombinant MIF (rMIF) of GC-induced MKP1 expression in RA fibroblast-like synoviocytes (FLS). rMIF enhanced NURR1 expression, artificial NBRE (orphan receptor DNA-binding site) reporter transactivation, and reversed GC-inhibition of NURR1. NURR1 expression was reduced during experimental arthritis in MIF-/- synovium, and silencing MIF reduced RA FLS NURR1 mRNA. Consistent with NBRE identification on the MKP1 gene, MKP1 mRNA was reduced in FLS that ectopically express NURR1, and silencing NURR1 enhanced MKP1 mRNA in RA FLS. rMIF enhanced NBRE binding on the MKP1 gene, and the absence of the NBRE prevented NURR1-repressive effects on basal and GC-induced MKP1 transactivation. This study defines NURR1 as a novel MIF target in chronic inflammation and demonstrates a role for NURR1 in regulating the anti-inflammatory mediator, MKP1. We propose a MIF-NURR1 signaling axis as a regulator of the GC sensitivity of MKP1.

Identification of NURR1 as a mediator of MIF signaling during chronic arthritis: effects on glucocorticoid-induced MKP1

Elucidation of factors regulating glucocorticoid (GC) sensitivity is required for the development of "steroid-sparing" therapies for chronic inflammatory diseases, including rheumatoid arthritis (RA). Accumulating evidence suggests that macrophage migration inhibitory factor (MIF) counterregulates the GC-induction of anti-inflammatory mediators, including mitogen-activated protein kinase phosphatase 1 (MKP1), a critical mitogen-activated protein kinase signaling inhibitor. This observation has yet to be extended to human disease; the molecular mechanisms remain unknown. We investigated NURR1, a GC-responsive transcription factor overexpressed in RA, as a MIF signaling target. We reveal abrogation by recombinant MIF (rMIF) of GC-induced MKP1 expression in RA fibroblast-like synoviocytes (FLS). rMIF enhanced NURR1 expression, artificial NBRE (orphan receptor DNA-binding site) reporter transactivation, and reversed GC-inhibition of NURR1. NURR1 expression was reduced during experimental arthritis in MIF-/- synovium, and silencing MIF reduced RA FLS NURR1 mRNA. Consistent with NBRE identification on the MKP1 gene, MKP1 mRNA was reduced in FLS that ectopically express NURR1, and silencing NURR1 enhanced MKP1 mRNA in RA FLS. rMIF enhanced NBRE binding on the MKP1 gene, and the absence of the NBRE prevented NURR1-repressive effects on basal and GC-induced MKP1 transactivation. This study defines NURR1 as a novel MIF target in chronic inflammation and demonstrates a role for NURR1 in regulating the anti-inflammatory mediator, MKP1. We propose a MIF-NURR1 signaling axis as a regulator of the GC sensitivity of MKP1.

Histamine modulation of peripheral CRH receptor type 1alpha expression is dependent on Ca(2+) signalling and NF-kappaB/p65 transcriptional activity

Histamine promotes immune complex-induced vascular leakage in vivo, a critical and early event that leads to joint-specific autoimmune damage. Initial assessment, using explanted human synovial tissue (ST), indicates that histamine can modulate local expression of type 1 alpha CRH receptors (CRH-R1alpha). The objective of this study was to elucidate the signalling events and transcriptional mechanism(s) controlling histamine-dependent regulation of CRH-R1alpha expression in human inflammatory arthritis. Histamine significantly promotes CRH-R1alpha mRNA and protein expression in a time- and concentration-dependent manner in human endothelial and synoviocyte cells. Transactivation of the human CRH-R1 promoter is significantly enhanced by histamine which can be mimicked by treatment with a Ca(2+) ionophore and completely diminished in the presence of a Ca(2+) chelator. Histamine-mediated responses involve enhanced activation and nuclear localisation of transcription factors including CREB, NF-kappaB and NR4A2. Functional consequences of enhanced CREB, NF-kappaB and NR4A2 activity confirm that NF-kappaB/p65 selectively controls CRH-R1 promoter activity. Co-transfection of NF-kappaB/p65 potently transactivates the CRH-R1 promoter while co-expression of a dominant negative IkappaBalpha kinase inhibits endogenous and histamine-induced promoter activity. Bioinformatic analysis identifies three putative kappaB consensus binding sites at proximal and distal positions and 5' deletional analysis identifies promoter region(s) required for activation by histamine and NF-kappaB/p65. We observe direct NF-kappaB/p65 interaction within the promoter region and site-directed mutagenesis reveals that all three kappaB sites are required to mediate histamine and NF-kappaB/p65 regulation of CRH-R1 promoter activity. These findings confirm that histamine, via enhanced Ca(2+) signalling and NF-kappaB/p65 activity, contributes to changes in ST inflammation by promoting CRH-R1alpha-mediated responses.