Tracking Cardiovascular Comorbidity in Models of Chronic Inflammatory Disease.

Immune-mediated inflammatory diseases (IMIDs) are commonly associated with complex coexisting conditions, and cardiovascular comorbidities are a common cause of mortality in systemic inflammation. Experimental models of disease provide an opportunity to dissect inflammatory mechanisms that promote damage to vascular tissues affected by comorbidity. Here, we describe methods to recover the thoracic aorta from mice during experimental inflammatory arthritis and assess vascular constriction responses by isometric tension myography. To complement the assessment of functional changes in the vasculature during inflammatory arthritis, we also outline a method to characterize vascular inflammation by immunohistochemistry.

Utilising quality of life outcome trajectories to aid patient decision making in pelvic exenteration.

BACKGROUND: Shared decision-making in pelvic exenteration is a complex and detailed process, which must balance clinical, oncological and patient-reported outcomes (PROs), whilst addressing and valuing the patient priorities. Communicating patient-centred information on quality of life (QoL) and functional outcomes is an essential component of this. The aim of this systematic review was to understand the impact of pelvic exenteration on QoL PROs over a longitudinal period and to develop QoL trajectories to support decision-making in this context. METHODS: MEDLINE, Embase and Web of Science databases were searched between 1st January 2000 and 20th December 2021 Studies reporting on PROs, including QoL, in adults undergoing pelvic exenteration were included. Risk of bias was assessed using the ROBINS-I assessment tool. Data from studies reporting QoL using the same outcome measure at the same candidate timepoint were extracted and synthesised to develop a longitudinal QoL trajectory. RESULTS: Fourteen studies consisting of 1370 patients were included in this review. QoL trajectories were constructed in the domains of physical function, psychological function, role function, sexual function, body image and general and specific symptoms. Decision-making was only assessed by one study, with satisfaction with decision-making reported to be high. There is an initial decline in QoL scores in the domains of physical function, role function, sexual function, body image and general health and symptoms deteriorating during the first 3-6 months post-operatively. Psychological function is the only QoL domain that remains stable throughout the post-operative period. CONCLUSION: Mapping QoL trajectories provides a visual representation of post-operative progress, highlighting the enduring impact of pelvic exenteration on patients and can be used to inform pre-operative shared decision-making.

Designing and evaluating a patient decision aid for patients with locally advanced or locally recurrent rectal cancer: a national multicentre mixed methods study protocol.

INTRODUCTION: Approximately 5%-10% of new rectal cancers are locally advanced (locally advanced rectal cancer (LARC)) at presentation with 4%-8% recurring (locally recurrent rectal cancer (LRRC)) after initial treatment. Patients with potentially curable disease have to consider many trade-offs when considering major exenterative surgery. There are no decision tools for these patients and current resources have found to not meet minimum international standards. The overall aim of this study is to produce a validated patient decision aid (PtDA) to assist patients considering radical pelvic exenteration for LARC and LRRC created in line with international minimum standards. METHODS AND ANALYSIS: This study is a national, multicentre mixed methods project and has been designed in keeping with guidance from the International Patient Decision Aids Standard.This study is in four stages. In stage 1, we will develop the PtDA and its content using agile developmental methodology. In stage 2, we will assess the content and face validity of the PtDA using mixed-methods with key stakeholders. In stage 3, we will assess the feasibility and efficacy of the PtDA. In stage 4, we will establish the barriers and facilitators to the use of a PtDA in the outpatient setting. Questionnaires including the QQ-10, EORTC PATSAT-C33, Preparation for Decision-Making Scale and the NoMAD survey will be analysed during the study. Interviews will be analysed using thematic analysis. ETHICS AND DISSEMINATION: Research ethics approval from North of Scotland Research Ethics Service 19/NS/0056 (IRAS 257890) has been granted. Results will be published in open access peer-reviewed journals, presented in conferences and distributed through bowel research UK charity. External endorsement will be sought from the International Patient Decision Standards Collaboration inventory of PtDAs. PROSPERO REGISTRATION NUMBER: CRD42019122933.

Nurse and allied health professional experiences and attitudes toward critical care research: A national questionnaire study.

Introduction: The aim of this study was to investigate nurse and allied health professional experiences and attitudes toward critical care research in Wales. Methods: Data were collected related to demographic characteristics, involvement in and understanding of research, perceived influences and attitudes towards research. We calculated means (ranges) for continuous variable and frequencies (proportions) for discrete variables and performed an exploratory factor analysis. Results: Response rate was 55% (n = 575). Most respondents (84%) had participated in research less than five times in the previous 12 months, yet 91% believed research led to improved care patients. Only 32% respondents felt they were encouraged by managers to participate in research. Only 25% respondents had undertaken research training. Few respondents (29%) reported receiving adequate information regarding study progress or results (25%). Linear regression models indicate that a higher level of formal education was associated with a more positive view of research across all attitude factors. Promotion of research by colleagues and recognition/ opportunities for involvement in critical care research, were positively associated with the acceptability and experience of research. Discussion: A number of factors have been identified that could be targeted to improve recruitment to critical care research, including identification of staff to promote research, improved communication of study progress and findings and management encouragement to attend research training. Staff attitudes were positive towards the benefit of research on patient care in Wales.

The role of interleukin-6 trans-signalling on cardiovascular dysfunction in inflammatory arthritis.

OBJECTIVES: Cardiovascular (CV) mortality in RA patients is 50% higher than in the general population. There is increasing recognition that systemic inflammation is a major driver of this. IL-6 is implicated in cardiovascular disease (CVD) in the general population but its role in CVD in RA is undefined. Of the two modes of IL-6 signalling, trans-signalling is pro-inflammatory whereas classical signalling is linked with inflammation resolution. This study examines the role of IL-6 trans-signalling in CVD in a mouse model and patients with RA. METHODS: Myography determined the effect of IL-6 trans-signalling blockade, using sgp130Fc, on aortic constriction in murine collagen-induced arthritis. Serum CCL2 and sVCAM-1 as soluble biomarkers of sIL-6R trans-signalling were investigated in a human cross-sectional study. An observational longitudinal study investigated the association between these biomarkers and progression of subclinical atherosclerosis in early RA by measuring carotid intima-media thickness (CIMT). RESULTS: sgp130Fc reduced arthritis severity, serum CCL2 and sVCAM-1 and restored vascular function in collagen-induced arthritis (CIA). In established RA, sVCAM-1 correlated with the 28-joint DAS (DAS28) and CV risk. In early RA, baseline DAS28 was associated with CIMT change at 6 months. CIMT 'rapid progressors' at 12 months had higher baseline sVCAM-1, haemoglobin A1c, cholesterol:high-density lipoprotein cholesterol ratio and LDL cholesterol. CONCLUSIONS: IL-6 trans-signalling plays a pivotal role in vascular dysfunction in CIA. In early RA, sVCAM-1 was associated with progression of subclinical atherosclerosis. Inflammation from RA onset in CVD-susceptible individuals may accelerate atherosclerosis. IL-6 trans-signalling blockade may be beneficial to RA patients and perhaps for atherosclerosis in the general population.

AMPA/kainate glutamate receptor antagonists prevent posttraumatic osteoarthritis.

Musculoskeletal disorders represent the third greatest burden in terms of death and disability in the developed world. Osteoarthritis is the single greatest cause of chronic pain, has no cure, and affects 8.5 and 27 million people in the UK and US, respectively. Osteoarthritis is most prevalent in older people, but as it commonly occurs after joint injury, young people with such injuries are also susceptible. Painful joints are often treated with steroid or hyaluronic acid (HA) injections, but treatments to prevent subsequent joint degeneration remain elusive. In animals, joint injury increases glutamate release into the joint, acting on nerves to cause pain, and joint tissues to cause inflammation and degeneration. This study investigated synovial fluid glutamate concentrations and glutamate receptor (GluR) expression in injured human joints and compared the efficacy of GluR antagonists with current treatments in a mouse model of injury-induced osteoarthritis (ACL rupture). GluRs were expressed in the ligaments and meniscus after knee injury, and synovial fluid glutamate concentrations ranged from 19 to 129 µM. Intra-articular injection of NBQX (GluR antagonist) at the time of injury substantially reduced swelling and degeneration in the mouse ACL rupture model. HA had no effect, and Depo-Medrone reduced swelling for 1 day but increased degeneration by 50%. Intra-articular administration of NBQX modified both symptoms and disease to a greater extent than current treatments. There is an opportunity for repurposing related drugs, developed for CNS disorders and with proven safety in humans, to prevent injury-induced osteoarthritis. This could quickly reduce the substantial burden associated with osteoarthritis.

CD28- Cells Are Increased in Early Rheumatoid Arthritis and Are Linked With Cytomegalovirus Status.

Objective: CD3+CD8+CD28- cells are higher in Rheumatoid Arthritis (RA). The aim of this study was to assess CD3+CD8+CD28- cells in patients with early RA and assess the effects of cytomegalovirus (CMV) seropositivity. Method: In this prospective observation study, 50 RA patients were recruited from Cardiff University Hospital of Wales (UHW) rheumatology outpatient, 25 patients with early disease (disease duration 0-6 months) and 25 patients with established disease (>2 years). These were compared with 25 healthy controls. Clinical and serological markers of inflammation were noted, and peripheral blood mononuclear cells were analyzed using flow cytometry. Results: The percentage of the CD8+CD28- T cells was increased in RA patients and was associated with disease duration. The percentage of CD8+CD28- T cells was increased in CMV positive early and established RA grouped and early RA patients in comparison to CMV negative patients (p < 0.05). There is a weak but statistically significant correlation between the percentage of CD3+CD8+CD28- cells and CRP in CMV positive RA patients (r = 0.227, p < 0.05). Conclusion: The percentage of CD8+CD28- T cells is higher in RA patients and correlates with disease duration, highlighting a potential role early in the disease process. These cells were also higher in CMV positive early RA patients which may suggest a role of CMV in disease development.

Oestrogen-deficiency induces bone loss by modulating CD14+ monocyte and CD4+ T cell DR3 expression and serum TL1A levels.

BACKGROUND: Oestrogen-deficiency induced by menopause is associated with reduced bone density and primary osteoporosis, resulting in an increased risk of fracture. While the exact etiology of menopause-induced primary osteoporotic bone loss is not fully known, members of the tumour necrosis factor super family (TNFSF) are known to play a role. Recent studies have revealed that the TNFSF members death receptor 3 (DR3) and one of its ligands, TNF-like protein 1A (TL1A) have a key role in secondary osteoporosis; enhancing CD14+ peripheral blood mononuclear cell (PBMC) osteoclast formation and bone resorption. Whether DR3 and TL1A contribute towards bone loss in menopause-induced primary osteoporosis however, remains unknown. METHODS: To investigate this we performed flow cytometry analysis of DR3 expression on CD14+ PBMCs isolated from pre- and early post-menopausal females and late post-menopausal osteoporotic patients. Serum levels of TL1A, CCL3 and total MMP-9 were measured by ELISA. In vitro osteoclast differentiation assays were performed to determine CD14+ monocyte osteoclastogenic potential. In addition, splenic CD4+ T cell DR3 expression was investigated 1 week and 8 weeks post-surgery, using the murine ovariectomy model. RESULTS: In contrast to pre-menopausal females, CD14+ monocytes isolated from post-menopausal females were unable to induce DR3 expression. Serum TL1A levels were decreased approx. 2-fold in early post-menopausal females compared to pre-menopausal controls and post-menopausal osteoporotic females; no difference was observed between pre-menopausal and late post-menopausal osteoporotic females. Analysis of in vitro CD14+ monocyte osteoclastogenic potential revealed no significant difference between the post-menopausal and post-menopausal osteoporotic cohorts. Interestingly, in the murine ovariectomy model splenic CD4+ T cell DR3 expression was significantly increased at 1 week but not 8 weeks post-surgery when compared to the sham control. CONCLUSION: Our results reveals for the first time that loss of oestrogen has a significant effect on DR3; decreasing expression on CD14+ monocytes and increasing expression on CD4+ T cells. These data suggest that while oestrogen-deficiency induced changes in DR3 expression do not affect late post-menopausal bone loss they could potentially have an indirect role in early menopausal bone loss through the modulation of T cell activity.

A comparison of doctoral training in biomedicine and medicine for some UK and Scandinavian graduate programmes: learning from each other.

Although the historical bases for graduate training in the United Kingdom (UK) and Scandinavia both stem from the original concept developed by von Humboldt, and both award a 'PhD degree', their paths have diverged. There are thus significant differences in the manner in which graduate training is organised. To analyse these differences, two UK graduate programmes (School of Medicine, Cardiff University; Institute of Integrative Biology, University of Liverpool) and two Scandinavian graduate schools (Faculty of Medicine and Dentistry, University of Bergen; Karolinska Institutet, Stockholm) completed a Self-evaluation questionnaire developed by Organisation of PhD Education in Biomedicine and Health Sciences in the European System (ORPHEUS)). Analysis of the completed questionnaires shows differences concerning requirements for admission, the training content of PhD programmes, the format of the PhD thesis, how the thesis is assessed and the financial model. All programmes recognise that PhD training should prepare for employment both inside and outside of academia, with emphasis on transferable skills training. However, the analysis reveals some fundamental differences in the direction of graduate programmes in the UK and Scandinavia. In the UK, graduate programmes are directed primarily towards teaching PhD students to do research, with considerable focus on practical techniques. In Scandinavia, the focus is on managing projects and publishing papers. To some extent, the differences lead to a lack of full recognition of each other's theses as a basis for doing a postdoc. This paper describes the basis for these differences and compares the two approaches and points to areas in which there is, or might be, convergence.

Mode of presentation rather than the 'weekend effect' is a major determinant of in-hospital mortality.

BACKGROUND: The influence of patient demographics and mode of admission on the 'weekend effect' remains unclear. This study examins the relationship between day of admission, patient demographics, mode of presentation and survival. METHODS: Hospital admissions over a three-year period were studied. Patients with an inpatient stay less than 24 h and those who were discharged from the emergency department were excluded. In-hospital mortality was correlated with day of admission, age, gender and mode of presentation in a binary logistical regression analysis. RESULTS: There were 448,827 admissions, of which 350,648 (85.7%) occurred during a weekday. 256,777 (62.7%) were emergency presentations, which was closely related to a weekend admission (92.3% vs 57.8%, p < 0.001). There were 8099 deaths of which 6336 (78.2%) related to a weekday admission and 1736 (21.4%) related a weekend admission. Mortality for elective admissions was 78 (0.05%) compared to 8021 (3.12%), p < 0.001 in emergency admissions. Univariable regression analysis revealed a weekend admission (Odds Ratio (OR) 1.68 (95% confidence interval (CI) 1.60-1.78, p < 0.001) and emergency presentation (OR 63.02 (95%CI 50.42-78.77), p < 0.011) were associated with weekend mortality. On multivariable analysis the OR for weekend admission reduced to 1.07 (95%CI 1.01-1.13), p = 0.013 and the OR for emergency presentation increased to 76.68 (95%CI 61.40-96.00), p < 0.001. CONCLUSION: This study highlights that higher weekend mortality rates are a consequence of a lower proportion of elective admissions. Extending the working week to seven days might reduce weekend mortality without reducing the total number of deaths.

Inhibition of CCL3 abrogated precursor cell fusion and bone erosions in human osteoclast cultures and murine collagen-induced arthritis.

Objective: Macrophage inflammatory protein 1-alpha (CCL3) is a chemokine that regulates macrophage trafficking to the inflamed joint. The agonistic effect of CCL3 on osteolytic lesions in patients with multiple myeloma is recognized; however, its role in skeletal damage during inflammatory arthritis has not been established. The aim of the study was to explore the role of osteoclast-associated CCL3 upon bone resorption, and to test its pharmacological blockade for protecting against bone pathology during inflammatory arthritis. Methods: CCL3 production was studied during osteoclast differentiation from osteoclast precursor cells: human CD14-positive mononuclear cells. Mice with CIA were treated with an anti-CCL3 antibody. The effect of CCL3 blockade through mAb was studied through osteoclast number, cytokine production and bone resorption on ivory disks, and in vivo through CIA progression (clinical score, paw diameter, synovial inflammation and bone damage). Results: Over time, CCL3 increased in parallel with the number of osteoclasts in culture. Anti-CCL3 treatment achieved a concentration-dependent inhibition of osteoclast fusion and reduced pit formation on ivory disks (P ⩽ 0.05). In CIA, anti-CCL3 treatment reduced joint damage and significantly decreased multinucleated tartrate-resistant acid phosphatase-positive osteoclasts and erosions in the wrists (P < 0.05) and elbows (P < 0.05), while also reducing joint erosions in the hind (P < 0.01) and fore paws (P < 0.01) as confirmed by X-ray. Conclusion: Inhibition of osteoclast-associated CCL3 reduced osteoclast formation and function whilst attenuating arthritis-associated bone loss and controlling development of erosion in murine joints, thus uncoupling bone damage from inflammation. Our findings may help future innovations for the diagnosis and treatment of inflammatory arthritis.

In Vivo Models for Inflammatory Arthritis.

In vivo mouse models of inflammatory arthritis are extensively used to investigate pathogenic mechanisms governing inflammation-driven joint damage. Two commonly utilized models include collagen-induced arthritis (CIA) and methylated bovine serum albumin (mBSA) antigen-induced arthritis (AIA). These offer unique advantages for modeling different aspects of human disease. CIA involves breach of immunological tolerance resulting in systemic autoantibody-driven arthritis, while AIA results in local resolving inflammatory flares and articular T cell-mediated damage. Despite limitations that apply to all animal models of human disease, CIA and AIA have been instrumental in identifying pathogenic mediators, immune cell subsets and stromal cell responses that determine disease onset, progression, and severity. Moreover, these models have enabled investigation of disease phases not easily studied in patients and have served as testing beds for novel biological therapies, including cytokine blockers and small molecule inhibitors of intracellular signaling that have revolutionized rheumatoid arthritis treatment.

Treg Depletion Licenses T Cell-Driven HEV Neogenesis and Promotes Tumor Destruction.

T-cell infiltration into tumors represents a critical bottleneck for immune-mediated control of cancer. We previously showed that this bottleneck can be overcome by depleting immunosuppressive Foxp3+ regulatory T cells (Tregs), a process that can increase frequencies of tumor-infiltrating lymphocytes through promoting the development of specialized portals for lymphocyte entry, namely high endothelial venules (HEVs). In this paper, we used a carcinogen-induced tumor model that allows for coevolution of the tumor microenvironment and the immune response to demonstrate that Treg depletion not only results in widespread disruption to HEV networks in lymph nodes (LNs) but also activates CD8+ T cells, which then drive intratumoral HEV development. Formation of these vessels contrasts with ontogenic HEV development in LNs in that the process is dependent on the TNF receptor and independent of lymphotoxin ß receptor-mediated signaling. These intratumoral HEVs do not express the chemokine CCL21, revealing a previously undescribed intratumoral blood vessel phenotype. We propose a model where Treg depletion enables a self-amplifying loop of T-cell activation, which promotes HEV development, T-cell infiltration, and ultimately, tumor destruction. The findings point to a need to test for HEV development as part of ongoing clinical studies in patients with cancer. Cancer Immunol Res; 5(11); 1005-15. ©2017 AACR.

Death Receptor 3 regulates distinct pathological attributes of acute versus chronic murine allergic lung inflammation.

The Death Receptor 3 (DR3)/Tumour Necrosis Factor-like cytokine 1A (TL1A) axis stimulates effector T cells and type 2 innate lymphocytes (ILC2) that trigger cytokine release and drive disease pathology in several inflammatory and autoimmune diseases, including murine models of acute allergic lung inflammation (ALI). The aim of this study was to elucidate the role of DR3 in chronic ALI compared to acute ALI, using mice genetically deficient in the DR3 gene (DR3ko). Results showed DR3 expression in the lungs of wild-type mice was up-regulated following induction of acute ALI and this increased expression was maintained in chronic disease. DR3ko mice were resistant to cellular accumulation within the alveolar passages in acute, but not chronic ALI. However, DR3ko mice displayed reduced immuno-histopathology and goblet cell hyperplasia; hallmarks of the asthmatic phenotype; in chronic, but not acute ALI. These data suggest DR3 is a potential therapeutic target, involved in temporally distinct aspects of ALI progression and pathogenesis.

Alterations to adipose tissue morphology during inflammatory arthritis is indicative of vasculopathology in DBA/1 mice.

The physiologic function of adipose tissue is altered by the host's inflammatory response; the implications for maintaining human health and regulating inflammation-associated disease progression are ill defined. However, this cannot be investigated in humans, therefore the use of animal models is required. With the aim to determine morphological and molecular alterations to perivascular and organ-associated adipose tissues during inflammatory arthritis, collagen-induced arthritis (CIA) was established in male DBA/1 mice. Emerging evidence from this study signposts CIA in the DBA/1 mouse as a model that is relevant to study the development and treatment of early cardiovascular pathology associated with inflammatory arthritis. Here, we show global morphological changes in adipose tissue and the thoracic aorta in animals induced with CIA compared with the non-immunized controls. In CIA, we concluded that the increased cell count in PVAT was, at least in part, caused by an ingress and/or expansion of macrophages that had a mixed phenotype. A substantial increase of galectin-3 was expressed in PVAT from mice with CIA. Galectin-3 is elevated in the blood of patients with CVDs, however, it has never before been measured in PVAT in rodents or humans. Here, PVAT-associated galectin-3 is identified as a potential biomarker for detecting early vascular pathology in CIA and a promising candidate for translation to RA.

CCL3 and MMP-9 are induced by TL1A during death receptor 3 (TNFRSF25)-dependent osteoclast function and systemic bone loss.

Reduced bone density and secondary osteoporosis, resulting in increased risk of fracture, is a significant complicating factor in the inflammatory arthritides. While the exact etiology of systemic bone loss is not fully elucidated, recent insights into the tumor necrosis factor super family (TNFSF) revealed a potential role for death receptor 3 (DR3/TNFRSF25) and one of its ligands, TNF-like protein 1A (TL1A/TNFSF15). The mechanisms by which DR3/TL1A signalling modulates bone loss are unclear. We investigated the effect of DR3/TL1A signalling upon osteoclast-dependent chemokine and MMP production to unravel novel mechanisms whereby this pathway regulates OC formation and OC-dependent bone resorption. Collagen induced arthritis (CIA) was established in DR3wt and DR3ko mice, joints were sectioned and analysed histologically for bone damage while systemic trabecular bone loss distal to the affected joints was compared by micro-CT. Ablation of DR3 protected DBA/1 mice against the development and progression of CIA. In DR3ko, joints of the ankle and mid-foot were almost free of bone erosions and long bones of mice with CIA were protected against systemic trabecular bone loss. In vitro, expression of DR3 was confirmed on primary human CD14+ osteoclast precursors by flow cytometry. These cells were treated with TL1A in osteoclast differentiation medium and TRAP+ osteoclasts, bone resorption, levels of osteoclast-associated chemokines (CCL3, CCL2 and CXCL8) and MMP-9 measured. TL1A intensified human osteoclast differentiation and bone resorption and increased osteoclast-associated production of CCL3 and MMP-9. Our data reveals the DR3 pathway as an attractive therapeutic target to combat adverse bone pathology associated with inflammatory arthritis. We demonstrate that DR3 is critical in the pathogenesis of murine CIA and associated secondary osteoporosis. Furthermore, we identify a novel mechanism by which the DR3/TL1A pathway directly enhances human OC formation and resorptive activity, controlling expression and activation of CCL3 and MMP-9.

A case of Finegoldia magna (formerly Peptostreptococcus magnus) infection mimicking disseminated malignancy.

A 44-year-old alcoholic (and therefore immunocompromised) hospital cleaner presented with general malaise, weight loss, and erythematous skin nodules. Computed tomography scanning revealed a neck mass invading the thyroid gland, pulmonary infiltrates, liver lesions, and deposits on the anterior abdominal wall, consistent with disseminated malignancy. However, tissue diagnosis showed a necro-inflammatory process with no evidence of malignancy. Microscopy and culture of samples failed to detect any infectious pathogen, but after an extended incubation period, Finegoldia magna was isolated. This case study illustrates the importance of tissue diagnosis in suspected disseminated malignancy and raises the risk of acquiring the rarer bacteria amongst hospital staff.

Death Receptor 3 Promotes Chemokine-Directed Leukocyte Recruitment in Acute Resolving Inflammation and Is Essential for Pathological Development of Mesothelial Fibrosis in Chronic Disease.

Death receptor 3 (DR3; TNFRSF25) and its tumor necrosis factor-like ligand TL1A (TNFSF15) control several processes in inflammatory diseases through the expansion of effector T cells and the induction of proinflammatory cytokines from myeloid and innate lymphoid cells. Using wild-type (DR3+/+) and DR3-knockout (DR3-/-) mice, we show that the DR3/TL1A pathway triggers the release of multiple chemokines after acute peritoneal inflammation initiated by a single application of Staphylococcus epidermidis supernatant, correlating with the infiltration of multiple leukocyte subsets. In contrast, leukocyte infiltration was not DR3 dependent after viral challenge with murine cytomegalovirus. DR3 expression was recorded on connective tissue stroma, which provided DR3-dependent release of chemokine (C-C motif) ligand (CCL) 2, CCL7, CXCL1, and CXCL13. CCL3, CCL4, and CXCL10 production was also DR3 dependent, but quantitative RT-PCR showed that their derivation was not stromal. In vitro cultures identified resident macrophages as a DR3-dependent source of CCL3. Whether DR3 signaling could contribute to a related peritoneal pathology was then tested using multiple applications of S. epidermidis supernatant, the repetitive inflammatory episodes of which lead to peritoneal membrane thickening and collagen deposition. Unlike their DR3+/+ counterparts, DR3-/- mice did not develop fibrosis of the mesothelial layer. Thus, this work describes both a novel function and essential requirement for the DR3/TL1A pathway in acute, resolving, and chronic inflammation in the peritoneal cavity.

Characterization of death receptor 3-dependent aortic changes during inflammatory arthritis.

Murine collagen-induced arthritis (mCIA) is characterized by decreased vascular constriction responses and increased MMP-9. Here, we describe additional histological alterations within the aorta and surrounding perivascular adipose tissue (PVAT), study the role of PVAT in constriction response, and investigate the potential involvement of death receptor 3 (DR3). mCIA was induced in wild-type (WT) and DR3-/- mice with nonimmunized, age-matched controls. Vascular function was determined in isolated aortic rings ±PVAT, using isometric tension myography, in response to cumulative serotonin concentrations. Cellular expression of F4/80 (macrophages), Ly6G (neutrophils), DR3, and MMP-9 was determined using immunohistochemistry. In WTs, arthritis-induced vascular dysfunction was associated with increased F4/80+ macrophages and increased DR3 expression in the aorta and PVAT. MMP-9 was also up-regulated in PVAT, but did not correlate with alterations of PVAT intact constriction. DR3-/- mice inherently showed increased leukocyte numbers and MMP-9 expression in the PVAT, but retained the same nonarthritic constriction response as DR3WT mice ±PVAT. Arthritic DR3-/- mice had a worsened constriction response than DR3WT and showed an influx of neutrophils to the aorta and PVAT. Macrophage numbers were also up-regulated in DR3-/- PVAT. Despite this influx, PVAT intact DR3-/- constriction responses were restored to the same level as DR3WT. Impaired vascular constriction in inflammatory arthritis occurs independently of total MMP-9 levels, but correlates with macrophage and neutrophil ingress. Ablating DR3 worsens the associated vasculature dysfunction, however, DR3-/- PVAT is able to protect the aorta against aberrant vasoconstriction caused in this model.