Regulation of entheseal IL-23 expression by IL-4 and IL-13 as an explanation for arthropathy development under dupilumab therapy.

OBJECTIVES: Dupilumab blocks the IL-4 receptor (IL-4R) and thus signalling of the 'Th2' cytokines IL-4 and IL-13. It has a license to treat atopic eczema and was recently linked to emergent enthesitis and psoriasis. We investigated the cellular and functional basis for how IL-4/IL-13 regulates the IL-23-IL-17 axis in entheseal stromal, myeloid and lymphocyte cells. METHODS: Immunohistochemistry was performed on healthy enthesis samples from patients undergoing elective spinal surgery to investigate entheseal tissue IL-4R expression and cytokine expression by intracellular flow cytometry for IL-4 and IL-13. Digested human enthesis samples were stimulated with lipopolysaccharide (LPS) for IL-23 induction, either alone or with IL-4 or IL-13. Enthesis fibroblasts were stimulated with TNF and IL-17 with and without IL-4 or IL-13 to assess the effect on CCL20 secretion. Synovial fluid samples from PsA patients were also analysed by ELISA for levels of IL-4 and IL-13. RESULTS: The IL-4/IL-13 receptor was present in both the peri-entheseal bone and enthesis soft tissue, and entheseal-derived T cells produced basal levels of IL-4, but not IL-13. Both IL-4 and IL-13 attenuated LPS-induced entheseal IL-23 production. IL-4 also downregulated secretion of TNF/IL-17A-induced CCL20 from entheseal fibroblasts. Both IL-13 and IL-4 were also detectable in the synovial fluid of PsA patients. We also noted a seronegative inflammatory oligoarthritis whilst under dupilumab therapy. CONCLUSION: Our findings suggest a previously unknown protective role for IL-4/IL-13 in entheseal induction of the IL-23-IL-17 axis. These findings point towards a novel explanation for IL-13 pathway single nucleotide polymorphisms in PsA and also a molecular explanation for why anti-IL-4/IL-13 therapy may induce musculoskeletal entheseal pathology as recently reported.

Normal human enthesis harbours conventional CD4+ and CD8+ T cells with regulatory features and inducible IL-17A and TNF expression.

BACKGROUND: The human enthesis conventional T cells are poorly characterised. OBJECTIVES: To study the biology of the conventional T cells in human enthesis. METHODS: CD4+ and CD8+ T cells were investigated in 25 enthesis samples using immunofluorescence, cytometrically, bulk RNAseq and quantitative real-time PCR following anti-CD3/CD28 bead stimulation to determine interleukin (IL)-17A and tumour necrosis factor (TNF) levels. T-cell receptor (TCR) repertoires were characterised and a search for putative T-cell reactivity was carried out using TCR3 database. The impact of pharmacological antagonism with retinoic acid receptor-related orphan nuclear receptor gamma t inhibitor (RORγti), methotrexate and phosphodiesterase type 4 inhibitor (PDE4i) was investigated. RESULTS: Immunofluorescence and cytometry suggested entheseal resident CD4+ and CD8+ T cells with a resident memory phenotype (CD69+/CD45RA-) and tissue residency gene transcripts (higher NR4A1/AhR and lower KLF2/T-bet transcripts). Both CD4+ and CD8+ T cells showed increased expression of immunomodulatory genes including IL-10 and TGF-ß compared with peripheral blood T cells with entheseal CD8+ T cells having higher CD103, CD49a and lower SIPR1 transcript that matched CD4+ T cells. Following stimulation, CD4+ T cells produced more TNF than CD8+ T cells and IL-17A was produced exclusively by CD4+ T cells. RNAseq suggested both Cytomegalovirus and influenza A virus entheseal resident T-cell clonotype reactivity. TNF and IL-17A production from CD4+ T cells was effectively inhibited by PDE4i, while RORγti only reduced IL-17A secretion. CONCLUSIONS: Healthy human entheseal CD4+ and CD8+ T cells exhibit regulatory characteristics and are predicted to exhibit antiviral reactivity with CD8+ T cells expressing higher levels of transcripts suggestive of tissue residency. Inducible IL-17A and TNF production can be robustly inhibited in vitro.

Evidence that tissue resident human enthesis γδT-cells can produce IL-17A independently of IL-23R transcript expression.

OBJECTIVES: Murine models of interleukin (IL)-23-driven spondyloarthritis (SpA) have demonstrated entheseal accumulation of γδT-cells which were responsible for the majority of local IL-17A production. However, IL-23 blockers are ineffective in axial inflammation in man. This study investigated γδT-cell subsets in the normal human enthesis to explore the biology of the IL-23/17 axis. METHODS: Human spinous processes entheseal soft tissue (EST) and peri-entheseal bone (PEB) were harvested during elective orthopaedic procedures. Entheseal γδT-cells were evaluated using immunohistochemistry and isolated and characterised using flow cytometry. RNA was isolated from γδT-cell subsets and analysed by qPCR. Entheseal γδT-cells were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin, anti-CD3/28 or IL-23 and IL-17A production was measured by high-sensitivity ELISA and qPCR. RESULTS: Entheseal γδT-cells were confirmed immunohistochemically with Vδ1 and Vδ2 subsets that are cytometrically defined. Transcript profiles of both cell populations suggested tissue residency and immunomodulatory status. Entheseal Vδ2 cells expressed high relative abundance of IL-23/17-associated transcripts including IL-23R, RORC and CCR6, whereas the Vδ1 subset almost completely lacked detectable IL-23R transcript. Following PMA stimulation IL-17A was detectable in both Vδ1 and Vδ2 subsets, and following CD3/CD28 stimulation both subsets showed IL-17A and IL-17F transcripts with neither transcript being detectable in the Vδ1 subset following IL-23 stimulation. CONCLUSION: Spinal entheseal Vδ1 and Vδ2 subsets are tissue resident cells with inducible IL-17A production with evidence that the Vδ1 subset does so independently of IL-23R expression.

Identification of myeloid cells in the human enthesis as the main source of local IL-23 production.

OBJECTIVE: We investigated whether the normal human spinal enthesis contained resident myeloid cell populations, capable of producing pivotal proinflammatory cytokines including tumour necrosis factor (TNF) and interleukin (IL)-23 and determined whether these could be modified by PDE4 inhibition. METHODS: Normal human enthesis soft tissue (ST) and adjacent perientheseal bone (PEB) (n=15) were evaluated using immunohistochemistry (IHC), digested for myeloid cell phenotyping, sorted and stimulated with different adjuvants (lipopolysaccharide and mannan). Stimulated enthesis fractions were analysed for inducible production of spondyloarthropathy disease-relevant mediators (IL-23 full protein, TNF, IL-1ß and CCL20). Myeloid populations were also compared with matched blood populations for further mRNA analysis and the effect of PDE4 inhibition was assessed. RESULTS: A myeloid cell population (CD45+ HLADR+ CD14+ CD11c+) phenotype was isolated from both the ST and adjacent PEB and termed 'CD14+ myeloid cells' with tissue localisation confirmed by CD14+ IHC. The CD14- fraction contained a CD123+ HLADR+ CD11c- cell population (plasmacytoid dendritic cells). The CD14+ population was the dominant entheseal producer of IL-23, IL-1ß, TNF and CCL20. IL-23 and TNF from the CD14+ population could be downregulated by a PDE4I and other agents (histamine and 8-Bromo-cAMP) which elevate cAMP. Entheseal CD14+ cells had a broadly similar gene expression profile to the corresponding CD14+ population from matched blood but showed significantly lower CCR2 gene expression. CONCLUSIONS: The human enthesis contains a CD14+ myeloid population that produces most of the inducible IL-23, IL-1ß, TNF and CCL20. This population has similar gene expression profile to the matched blood CD14+ population.

24-Month Outcomes of Indirect Decompression Using a Minimally Invasive Interspinous Fixation Device versus Standard Open Direct Decompression for Lumbar Spinal Stenosis: A Prospective Comparison.

Purpose: An early-stage, multi-centre, prospective, randomised control trial with five-year follow-up was approved by Health Research Authority to compare the efficacy of a minimally invasive, laterally implanted interspinous fixation device (IFD) to open direct surgical decompression in treating lumbar spinal stenosis (LSS). Two-year results are presented. Patients and Methods: Forty-eight participants were randomly assigned to IFD or decompression. Primary study endpoints included changes from baseline at 8-weeks, 6, 12 and 24-months follow-ups for leg pain (visual analogue scale, VAS), back pain (VAS), disability (Oswestry Disability Index, ODI), LSS physical function (Zurich Claudication Questionnaire), distance walked in five minutes and number of repetitions of sitting-to-standing in one minute. Secondary study endpoints included patient and clinician global impression of change, adverse events, reoperations, operating parameters, and fusion rate. Results: Both treatment groups demonstrated statistically significant improvements in mean leg pain, back pain, ODI disability, LSS physical function, walking distance and sitting-to-standing repetitions compared to baseline over 24 months. Mean reduction of ODI from baseline levels was between 35% and 56% for IFD (p<0.002), and 49% to 55% for decompression (p<0.001) for all follow-up time points. Mean reduction of IFD group leg pain was between 57% and 78% for all time points (p<0.001), with 72% to 94% of participants having at least 30% reduction of leg pain from 8-weeks through 24-months. Walking distance for the IFD group increased from 66% to 94% and sitting-to-standing repetitions increased from 44% to 64% for all follow-up time points. Blood loss was 88% less in the IFD group (p=0.024) and operating time parameters strongly favoured IFD compared to decompression (p<0.001). An 89% fusion rate was assessed in a subset of IFD participants. There were no intraoperative device issues or re-operations in the IFD group, and only one healed and non-symptomatic spinous process fracture observed within 24 months. Conclusion: Despite a low number of participants in the IFD group, the study demonstrated successful two-year safety and clinical outcomes for the IFD with significant operation-related advantages compared to surgical decompression.

E-learning and research experience exchange in the online setting of student peer mentor network during COVID-19 pandemic and beyond: A laboratory case study.

For close to 2 years, we have witnessed the impacts of the SARS-CoV-2 pandemic on research at several different levels. Among the list, limited access to laboratory-based training for undergraduate students prevented this cohort from gaining exposure to the realities of a research laboratory at a critical time in training when they may have found motivation in this area as a career. COVID exposed a weakness in our training pipeline; an extreme dependency on face-to-face training that threatened to create a void in the research talent needed to replenish the scientific community every year. In the classroom, we witnessed a revolution of e-learning based approaches that could be rapidly implemented based on existing footprints. Out of necessity, our laboratory developed and implemented an e-learning model of an undergraduate peer mentor network that provides a knowledge and experience exchange platform between students with different levels of research experience. Implementation of the platform was to aid students with gaining knowledge in multiple aspects of scientific research and hands-on work in a research laboratory. The collaboration between the students of the network was aimed at not only advancing the theoretical and practical research experience, but also at developing feedback implementation and practicing "soft skills" critical for teamwork and leadership. Herein, we present an overview of the model along with survey responses of the students participating in the peer mentor network. We have found that peer delivery of practical benchwork both via scientific presentations and visualized experiments, reduced the time of training and the amount of staff assistance needed when students returned to the bench. Furthermore, this model accelerated student independence in laboratory work and increased research interest overall. In summary, the model of a peer mentor network has the potential to serve as a training platform and as a customized tool, supplementing research laboratory training at the undergraduate level beyond the pandemic.

Systematic review of microendoscopic discectomy for lumbar disc herniation.

STUDY DESIGN: Systematic review. OBJECTIVE: To search and analyse randomised controlled trials (RCTs) published since the Cochrane review by Gibson and Waddell (2007) comparing microendoscopic discectomy (MED) with open discectomy (OD) or microdiscectomy (MD) and to assess whether MED improves patient-reported outcomes. Discectomy for symptomatic herniated lumbar discs is an effective operative treatment. A number of operative techniques exist including OD, MD, and MED. A 2007 Cochrane review identified OD as an effective treatment for symptom improvement, and found sufficient evidence for MD. However, evidence for MED was lacking. METHODS: A systematic review of Medline and Embase was carried out. Aiming to identify RCTs carried out after 2007, which compared OD with MD and MED which reported the Oswestry disability index (ODI) as an outcome. RESULTS: Four RCTs were identified. None of the studies found a significant difference in the ODI scores between study groups at any time point. Three studies compared MED to OD and one compared OD, MD, and MED. The largest study reported an increased number of severe complications in the MED group. CONCLUSIONS: There is some evidence to suggest that MED performed by surgeons skilled in the technique in tertiary referral centres is as effective as OD.

The application of epiphenotyping approaches to DNA methylation array studies of the human placenta.

Background : Genome-wide DNA methylation (DNAme) profiling of the placenta with Illumina Infinium Methylation bead arrays is often used to explore the connections between in utero exposures, placental pathology, and fetal development. However, many technical and biological factors can lead to signals of DNAme variation between samples and between cohorts, and understanding and accounting for these factors is essential to ensure meaningful and replicable data analysis. Recently, "epiphenotyping" approaches have been developed whereby DNAme data can be used to impute information about phenotypic variables such as gestational age, sex, cell composition, and ancestry. These epiphenotypes offer avenues to compare phenotypic data across cohorts, and to understand how phenotypic variables relate to DNAme variability. However, the relationships between placental epiphenotyping variables and other technical and biological variables, and their application to downstream epigenome analyses, have not been well studied. Results : Using DNAme data from 204 placentas across three cohorts, we applied the PlaNET R package to estimate epiphenotypes gestational age, ancestry, and cell composition in these samples. PlaNET ancestry estimates were highly correlated with independent polymorphic ancestry informative markers, and epigenetic gestational age, on average, was estimated within 4 days of reported gestational age, underscoring the accuracy of these tools. Cell composition estimates varied both within and between cohorts, but reassuringly were robust to placental processing time. Interestingly, the ratio of cytotrophoblast to syncytiotrophoblast proportion decreased with increasing gestational age, and differed slightly by both maternal ethnicity (lower in white vs. non-white) and genetic ancestry (lower in higher probability European ancestry). The cohort of origin and cytotrophoblast proportion were the largest drivers of DNAme variation in this dataset, based on their associations with the first principal component. Conclusions : This work confirms that cohort, array (technical) batch, cell type proportion, self-reported ethnicity, genetic ancestry, and biological sex are important variables to consider in any analyses of Illumina DNAme data. Further, we demonstrate that estimating epiphenotype variables from the DNAme data itself, when possible, provides both an independent check of clinically-obtained data and can provide a robust approach to compare variables across different datasets.

Bracing Adolescent Idiopathic Scoliosis (BASIS) study - night-time versus full-time bracing in adolescent idiopathic scoliosis: study protocol for a multicentre, randomized controlled trial.

Aims: Scoliosis is a lateral curvature of the spine with associated rotation, often causing distress due to appearance. For some curves, there is good evidence to support the use of a spinal brace, worn for 20 to 24 hours a day to minimize the curve, making it as straight as possible during growth, preventing progression. Compliance can be poor due to appearance and comfort. A night-time brace, worn for eight to 12 hours, can achieve higher levels of curve correction while patients are supine, and could be preferable for patients, but evidence of efficacy is limited. This is the protocol for a randomized controlled trial of 'full-time bracing' versus 'night-time bracing' in adolescent idiopathic scoliosis (AIS). Methods: UK paediatric spine clinics will recruit 780 participants aged ten to 15 years-old with AIS, Risser stage 0, 1, or 2, and curve size (Cobb angle) 20° to 40° with apex at or below T7. Patients are randomly allocated 1:1, to either full-time or night-time bracing. A qualitative sub-study will explore communication and experiences of families in terms of bracing and research. Patient and Public Involvement & Engagement informed study design and will assist with aspects of trial delivery and dissemination. Discussion: The primary outcome is 'treatment failure' (Cobb angle progression to 50° or more before skeletal maturity); skeletal maturity is at Risser stage 4 in females and 5 in males, or 'treatment success' (Cobb angle less than 50° at skeletal maturity). The comparison is on a non-inferiority basis (non-inferiority margin 11%). Participants are followed up every six months while in brace, and at one and two years after skeletal maturity. Secondary outcomes include the Scoliosis Research Society 22 questionnaire and measures of quality of life, psychological effects of bracing, adherence, anxiety and depression, sleep, satisfaction, and educational attainment. All data will be collected through the British Spine Registry.

Determinants in Tailoring Antidiabetic Therapies: A Personalized Approach.

Diabetes has become a pandemic as the number of diabetic people continues to rise globally. Being a heterogeneous disease, it has different manifestations and associated complications in different individuals like diabetic nephropathy, neuropathy, retinopathy, and others. With the advent of science and technology, this era desperately requires increasing the pace of embracing precision medicine and tailoring of drug treatment based on the genetic composition of individuals. It has been previously established that response to antidiabetic drugs, like biguanides, sulfonylureas, dipeptidyl peptidase-4 (DPP-4) inhibitors, glucagon-like peptide 1 (GLP-1) agonists, and others, depending on variations in their transporter genes, metabolizing genes, genes involved in their action, etc . Responsiveness of these drugs also relies on epigenetic factors, including histone modifications, miRNAs, and DNA methylation, as well as environmental factors and the lifestyle of an individual. For precision medicine to make its way into clinical procedures and come into execution, all these factors must be reckoned with. This review provides an insight into several factors oscillating around the idea of precision medicine in type-2 diabetes mellitus.

Genetic Variants and Drug Efficacy in Tuberculosis: A Step toward Personalized Therapy.

Tuberculosis (TB) continues to be a major infectious disease affecting individuals worldwide. Current TB treatment strategy recommends the standard short-course chemotherapy regimen containing first-line drug, i.e., isoniazid, rifampicin, pyrazinamide, and ethambutol to treat patients suffering from drug-susceptible TB. Although Mycobacterium tuberculosis , the causing agent, is susceptible to drugs, some patients do not respond to the treatment or treatment may result in serious adverse reactions. Many studies revealed that anti-TB drug-related toxicity is associated with genetic variations, and these variations may also influence attaining maximum drug concentration. Thus, inter-individual diversities play a characteristic role by influencing the genes involved in drug metabolism pathways. The development of pharmacogenomics could bring a revolution in the field of treatment, and the understanding of germline variants may give rise to optimized targeted treatments and refine the response to standard therapy. In this review, we briefly introduced the field of pharmacogenomics with the evolution in genetics and discussed the pharmacogenetic impact of genetic variations on genes involved in the activities, such as anti-TB drug transportation, metabolism, and gene regulation.

A role for neutrophils in early enthesitis in spondyloarthritis.

BACKGROUND: Neutrophils are present in the early phases of spondyloarthritis-related uveitis, skin and intestinal disease, but their role in enthesitis, a cardinal musculoskeletal lesion in spondyloarthritis, remains unknown. We considered the role of neutrophils in the experimental SKG mouse model of SpA and in human axial entheses. METHODS: Early inflammatory infiltrates in the axial and peripheral entheseal sites in SKG mice were evaluated using immunohistochemistry and laser capture microdissection of entheseal tissue. Whole transcriptome analysis was carried out using Affymetrix gene array MTA 1.0, and data was analyzed via IPA. We further isolated neutrophils from human peri-entheseal bone and fibroblasts from entheseal soft tissue obtained from the axial skeleton of healthy patients and determined the response of these cells to fungal adjuvant. RESULTS: Following fungal adjuvant administration, early axial and peripheral inflammation in SKG mice was characterized by prominent neutrophilic entheseal inflammation. Expression of transcripts arising from neutrophils include abundant mRNA for the alarmins S100A8 and S100A9. In normal human axial entheses, neutrophils were present in the peri-entheseal bone. Upon fungal stimulation in vitro, human neutrophils produced IL-23 protein, while isolated human entheseal fibroblasts produced chemokines, including IL-8, important in the recruitment of neutrophils. CONCLUSION: Neutrophils with inducible IL-23 production are present in uninflamed human entheseal sites, and neutrophils are prominent in early murine spondyloarthritis-related enthesitis. We propose a role for neutrophils in the early development of enthesitis.

Profiling placental DNA methylation associated with maternal SSRI treatment during pregnancy.

Selective serotonin reuptake inhibitors (SSRIs) for treatment of prenatal maternal depression have been associated with neonatal neurobehavioral disturbances, though the molecular mechanisms remain poorly understood.  In utero exposure to SSRIs may affect DNA methylation (DNAme) in the human placenta, an epigenetic mark that is established during development and is associated with gene expression. Chorionic villus samples from 64 human placentas were profiled with the Illumina MethylationEPIC BeadChip; clinical assessments of maternal mood and SSRI treatment records were collected at multiple time points during pregnancy. Case distribution was 20 SSRI-exposed cases and 44 SSRI non-exposed cases. Maternal depression was defined using a mean maternal Hamilton Depression score > 8 to indicate symptomatic depressed mood ("maternally-depressed"), and we further classified cases into SSRI-exposed, maternally-depressed (n = 14); SSRI-exposed, not maternally-depressed (n = 6); SSRI non-exposed, maternally-depressed (n = 20); and SSRI non-exposed, not maternally-depressed (n = 24). For replication, Illumina 450K DNAme profiles were obtained from 34 additional cases from an independent cohort (n = 17 SSRI-exposed, n = 17 SSRI non-exposed). No CpGs were differentially methylated at FDR < 0.05 comparing SSRI-exposed to non-exposed placentas, in a model adjusted for mean maternal Hamilton Depression score, or in a model restricted to maternally-depressed cases with and without SSRI exposure. However, at a relaxed threshold of FDR < 0.25, five CpGs were differentially methylated (|Δß| > 0.03) by SSRI exposure status. Four were covered by the replication cohort measured by the 450K array, but none replicated. No CpGs were differentially methylated (FDR < 0.25) comparing maternally depressed to not depressed cases. In sex-stratified analyses for SSRI-exposed versus non-exposed cases (females n = 31; males n = 33), three additional CpGs in females, but none in males, were differentially methylated at the relaxed FDR < 0.25 cut-off. We did not observe large-scale alterations of DNAme in placentas exposed to maternal SSRI treatment, as compared to placentas with no SSRI exposure. We also found no evidence for altered DNAme in maternal depression-exposed versus depression non-exposed placentas. This novel work in a prospectively-recruited cohort with clinician-ascertained SSRI exposure and mood assessments would benefit from future replication.

Increased prevalence of idiopathic scoliosis in patients treated for childhood haematopoietic malignancy.

AIMS: The aim of this study was to determine whether there is an increased prevalence of scoliosis in patients who have suffered from a haematopoietic malignancy in childhood. METHODS: Patients with a history of lymphoma or leukaemia with a current age between 12 and 25 years were identified from the regional paediatric oncology database. The medical records and radiological findings were reviewed, and any spinal deformity identified. The treatment of the malignancy and the spinal deformity, if any, was noted. RESULTS: From a cohort of 346 patients, 19 (5.5%) had radiological evidence of scoliosis, defined as a Cobb angle of > 10°. A total of five patients (1.4% of the total cohort) had a Cobb angle of > 40°, all of whom had corrective surgery. No patient with scoliosis had other pathology as a possible cause of the scoliosis and all had been treated with high doses of steroids for leukaemia, either acute or chronic myeloid, or acute lymphoblastic. CONCLUSION: There is an increased prevalence of idiopathic-like scoliosis and larger curves (Cobb angle of > 40°) associated with childhood leukaemia, which has not been previously reported in the literature. Causative factors may relate to the underlying disease process and/or its treatment. Cite this article: Bone Joint J 2021;103-B(8):1400-1404.

Surgical treatment of spinal stenosis in achondroplasia: Literature review comparing results in adults and paediatrics.

BACKGROUND: This study aims to assess the quantity and quality of available literature on surgical treatment outcomes of spinal stenosis in adult and paediatric achondroplasia patients through a systematic review of literature and to investigate the suitability of conducting a meta-analysis on outcomes of surgical treatment. METHODS: Online databases were searched according to PRISMA guidelines. No restrictions regarding study design, sample size, previous treatment, or publication date were implemented. The following terms: "Spinal stenosis", "Spinal Decompression", "Spinal fusion", each term separately combined with the term "Achondroplasia" were used. Quality of the included studies were assessed used the Modified Coleman method. RESULTS: Five adult and four paediatric single-sample non-comparative studies were identified for inclusion (176 adult and 102 paediatric patients). Meta-analyses assessed the proportion of patients achieving full resolution of symptoms to be 0.51 (95% CI 0.00 to 1.00); the proportion of patients achieving full or partial resolution of symptoms to be 0.90 (95% CI 0.84 to 0.97); the proportion of procedures requiring re-operation to be 0.42 (95% CI 0.34 to 0.50; and the proportion of procedures involving dural tears to be 0.20 (95% CI 0.02 to 0.39). Statistical heterogeneity was very high for full resolution of symptoms and requirement for dural repair; and very low for other outcomes. CONCLUSIONS: The available literature on this population and condition is sparse, highly heterogenous, and is generally of low quality limiting the value of meta-analysis. Overall, outcomes of surgical decompression of symptomatic spinal stenosis in achondroplasia patients show consistent degree of resolution of symptoms. Duration of symptoms prior to surgical treatment appears to play an important role in the overall outcome of treatment. Therefore, a delay in diagnosis and treatment can potentially be detrimental in achieving a better outcome.

Surgery versus conservative management of stable thoracolumbar fracture: the PRESTO feasibility RCT.

BACKGROUND: There is informal consensus that simple compression fractures of the body of the thoracolumbar vertebrae between the 10th thoracic vertebra and the second lumbar vertebra without neurological complications can be managed conservatively and that obvious unstable fractures require surgical fixation. However, there is a zone of uncertainty about whether surgical or conservative management is best for stable fractures. OBJECTIVES: To assess the feasibility of a definitive randomised controlled trial comparing surgical fixation with initial conservative management of stable thoracolumbar fractures without spinal cord injury. DESIGN: External randomised feasibility study, qualitative study and national survey. SETTING: Three NHS hospitals. METHODS: A feasibility randomised controlled trial using block randomisation, stratified by centre and type of injury (high- or low-energy trauma) to allocate participants 1 : 1 to surgery or conservative treatment; a costing analysis; a national survey of spine surgeons; and a qualitative study with clinicians, recruiting staff and patients. PARTICIPANTS: Adults aged ≥ 16 years with a high- or low-energy fracture of the body of a thoracolumbar vertebra between the 10th thoracic vertebra and the second lumbar vertebra, confirmed by radiography, computerised tomography or magnetic resonance imaging, with at least one of the following: kyphotic angle > 20° on weight-bearing radiographs or > 15° on a supine radiograph or on computerised tomography; reduction in vertebral body height of 25%; a fracture line propagating through the posterior wall of the vertebra; involvement of two contiguous vertebrae; or injury to the posterior longitudinal ligament or annulus in addition to the body fracture. INTERVENTIONS: Surgical fixation: open spinal surgery (with or without spinal fusion) or minimally invasive stabilisation surgery. Conservative management: mobilisation with or without a brace. MAIN OUTCOME MEASURE: Recruitment rate (proportion of eligible participants randomised). RESULTS: Twelve patients were randomised (surgery, n = 8; conservative, n = 4). The proportion of eligible patients recruited was 0.43 (95% confidence interval 0.24 to 0.63) over a combined total of 30.7 recruitment months. Of 211 patients screened, 28 (13.3%) fulfilled the eligibility criteria. Patients in the qualitative study (n = 5) expressed strong preferences for surgical treatment, and identified provision of information about treatment and recovery and when and how they are approached for consent as important. Nineteen surgeons and site staff participated in the qualitative study. Key themes were the lack of clinical consensus regarding the implementation of the eligibility criteria in practice and what constitutes a stable fracture, alongside lack of equipoise regarding treatment. Based on the feasibility study eligibility criteria, 77% (50/65) and 70% (46/66) of surgeons participating in the survey were willing to randomise for high- and low-energy fractures, respectively. LIMITATIONS: Owing to the small number of participants, there is substantial uncertainty around the recruitment rate. CONCLUSIONS: A definitive trial is unlikely to be feasible currently, mainly because of the small number of patients meeting the eligibility criteria. The recruitment and follow-up rates were slightly lower than anticipated; however, there is room to increase these based on information gathered and the support within the surgical community for a future trial. FUTURE WORK: Development of consensus regarding the population of interest for a trial. TRIAL REGISTRATION: Current Controlled Trials ISRCTN12094890. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 62. See the NIHR Journals Library website for further project information.

Fractures occurring in the mid- to low back region (or thoracolumbar fractures) are the most common back fractures. When the fracture is stable with no spinal nerve injury, there is uncertainty whether treatment with surgery or non-surgical treatment (e.g. stabilising the spine with a brace) results in the best outcome for patients. The Pragmatic Randomised Evaluation of Stable Thoracolumbar fracture treatment Outcomes (PRESTO) study aimed to explore whether or not it would be feasible to carry out a full-scale study to find out which of these two treatments works best. Adults aged ≥ 16 years being treated for these fractures in three hospitals were invited to take part in the study. Over the course of 1 year, we assessed how many patients were treated, the number who met the study entry criteria and the proportion of eligible patients who agreed to take part. Staff and patients were interviewed about the study processes and their experiences of taking part. Spine surgeons from around the UK were also asked to complete an online survey, which asked questions about the treatment of patients with this fracture. There were fewer patients than expected who met the study entry criteria and, of these, fewer patients who agreed to take part. There were differences among surgeons about the definition of a stable fracture, and we found that surgeons have strong views about whether or not surgery is appropriate when fractures are stable. We also found that more support would be required for the staff involved in inviting patients to take part in a bigger study, and that the format and content of information provided to patients needs to be improved. The findings of the PRESTO study showed that a large trial is unlikely to be successful at this time; however, we have provided important information for future research into the treatment of these fractures.

IL-17A and TNF Modulate Normal Human Spinal Entheseal Bone and Soft Tissue Mesenchymal Stem Cell Osteogenesis, Adipogenesis, and Stromal Function.

OBJECTIVE: The spondylarthritides (SpA) are intimately linked to new bone formation and IL-17A and TNF pathways. We investigated spinal soft tissue and bone mesenchymal stem cell (MSC) responses to IL-17A and TNF, including their osteogenesis, adipogenesis, and stromal supportive function and ability to support lymphocyte recruitment. METHODS: Normal spinal peri-entheseal bone (PEB) and entheseal soft tissue (EST) were characterized for MSCs by immunophenotypic, osteogenic, chondrogenic, and adipogenic differentiation criteria. Functional and gene transcriptomic analysis was carried out on undifferentiated, adipo- differentiated, and osteo-differentiated MSCs. The enthesis C-C Motif Chemokine Ligand 20-C-C Motif Chemokine Receptor 6 (CCL20-CCR6) axis was investigated at transcript and protein levels to ascertain whether entheseal MSCs influence local immune cell populations. RESULTS: Cultured MSCs from both PEB and EST displayed a tri-lineage differentiation ability. EST MSCs exhibited 4.9-fold greater adipogenesis (p < 0.001) and a 3-fold lower osteogenic capacity (p < 0.05). IL-17A induced greater osteogenesis in PEB MSCs compared to EST MSCs. IL-17A suppressed adipogenic differentiation, with a significant decrease in fatty acid-binding protein 4 (FABP4), peroxisome proliferator-activated receptor gamma (PPARγ), Cell Death Inducing DFFA Like Effector C (CIDEC), and Perilipin-1 (PLIN1). IL-17A significantly increased the CCL20 transcript (p < 0.01) and protein expression (p < 0.001) in MSCs supporting a role in type 17 lymphocyte recruitment. CONCLUSIONS: Normal spinal enthesis harbors resident MSCs with different in vitro functionalities in bone and soft tissue, especially in response to IL-17A, which enhanced osteogenesis and CCL20 production and reduced adipogenesis compared to unstimulated MSCs. This MSC-stromal-enthesis immune system may be a hitherto unappreciated mechanism of "fine tuning" tissue repair responses at the enthesis in health and could be relevant for SpA understanding.

SARS-CoV-2 Infection Induces Psoriatic Arthritis Flares and Enthesis Resident Plasmacytoid Dendritic Cell Type-1 Interferon Inhibition by JAK Antagonism Offer Novel Spondyloarthritis Pathogenesis Insights.

Objective: Bacterial and viral infectious triggers are linked to spondyloarthritis (SpA) including psoriatic arthritis (PsA) development, likely via dendritic cell activation. We investigated spinal entheseal plasmacytoid dendritic cells (pDCs) toll-like receptor (TLR)-7 and 9 activation and therapeutic modulation, including JAK inhibition. We also investigated if COVID-19 infection, a potent TLR-7 stimulator triggered PsA flares. Methods: Normal entheseal pDCs were characterized and stimulated with imiquimod and CpG oligodeoxynucleotides (ODN) to evaluate TNF and IFNα production. NanoString gene expression assay of total pDCs RNA was performed pre- and post- ODN stimulation. Pharmacological inhibition of induced IFNα protein was performed with Tofacitinib and PDE4 inhibition. The impact of SARS-CoV2 viral infection on PsA flares was evaluated. Results: CD45+HLA-DR+CD123+CD303+CD11c- entheseal pDCs were more numerous than blood pDCs (1.9 ± 0.8% vs 0.2 ± 0.07% of CD45+ cells, p=0.008) and showed inducible IFNα and TNF protein following ODN/imiquimod stimulation and were the sole entheseal IFNα producers. NanoString data identified 11 significantly upregulated differentially expressed genes (DEGs) including TNF in stimulated pDCs. Canonical pathway analysis revealed activation of dendritic cell maturation, NF-κB signaling, toll-like receptor signaling and JAK/STAT signaling pathways following ODN stimulation. Both tofacitinib and PDE4i strongly attenuated ODN induced IFNα. DAPSA scores elevations occurred in 18 PsA cases with SARS-CoV2 infection (9.7 ± 4 pre-infection and 35.3 ± 7.5 during infection). Conclusion: Entheseal pDCs link microbes to TNF/IFNα production. SARS-CoV-2 infection is associated with PsA Flares and JAK inhibition suppressed activated entheseal plasmacytoid dendritic Type-1 interferon responses as pointers towards a novel mechanism of PsA and SpA-related arthropathy.