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Susceptibility to inflammatory bowel diseases (IBDs), Crohn's disease (CD), and ulcerative colitis (UC) is linked with loss of intestinal epithelial barrier integrity and mitochondria dysfunction. Steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) domain-containing protein 7 (STARD7) is a phosphatidylcholine-specific (PC-specific) lipid transfer protein that transports PC from the ER to the mitochondria, facilitating mitochondria membrane stabilization and respiration function. The aim of this study was to define the contribution of STARD7 in the regulation of the intestinal epithelial mitochondrial function and susceptibility to colitis. In silico analyses identified significantly reduced expression of STARD7 in patients with UC, which was associated with downregulation of metabolic function and a more severe disease phenotype. STARD7 was expressed in intestinal epithelial cells, and STARD7 knockdown resulted in deformed mitochondria and diminished aerobic respiration. Loss of mitochondria function was associated with reduced expression of tight junction proteins and loss of intestinal epithelial barrier integrity that could be recovered by AMPK activation. Stard7+/- mice were more susceptible to the development of DSS-induced and Il10-/- spontaneous models of colitis. STARD7 is critical for intestinal epithelial mitochondrial function and barrier integrity, and loss of STARD7 function increases susceptibility to IBD. more...

Mast cells (MCs) are derived from CD34 + hematopoietic progenitors, consist of different subtypes, and are involved in several inflammatory conditions. However, our understanding of human MC developmental trajectories and subtypes has been limited by a scarcity of suitable cellular model systems. Herein, we developed an in vitro model of human MC differentiation from induced pluripotent stem cells (iPSC) to study human MC differentiation trajectories. Flow cytometry characterization of hemopoietic cells derived from the myeloid cells-forming complex (MCFC) revealed an initial increase in Lin - CD34 + hematopoietic progenitors within Weeks 1-3, followed by an increase in CD34 - CD45RA - SSC l ow and SSC high hematopoietic cells. The Lin - CD34 + hematopoietic progenitors consisted of SSC low CD45RA - CD123 ± c-Kit + FcεRI + populations that were β7-integrin high CD203c + and β7-integrin high CD203c - cells consistent with CMP Fc ε RI+ cells. Flow cytometry and cytologic analyses of the CD34 - Lin - (SSC low ) population revealed hypogranular cell populations, predominantly characterized by CD45RA - CD123 ± c-Kit + FcεRI - β7-integrin low and CD45RA - CD123 ± c-Kit - FcεRI + β7-integrin Mid cells. Analyses of hypergranular SSC high cells identified Lin - CD34 - CD45RA - c-Kit + FcεRI - and Lin - CD34 - CD45RA - c-Kit + FcεRI + cells. scRNA-seq analysis of the cells harvested at week 4 of the MCFC culture revealed the presence of monocyte and granulocyte progenitors (n = 547 cells, 26.7 %), Erythrocyte / unknown (n = 85, 4.1 %), neutrophils / myelocytes (n = 211 cells, 10.2 %), mast cell progenitor 1 (n = 599, 29.1 %), mast cell progenitor 2 (n = 152, 7.4 %), committed mast cell precursor (n = 113, 5.5 %), and MCs (n = 353, 17.1 %). In silico analyses of the MC precursor and mature MC populations revealed transcriptionally distinct MC precursor subtype and mature MC states (CMA1 + and CMA1 - subtypes). Culturing MC precursor populations in MC maturation media (mast cell media II) led to homogenous mature MC populations as evidenced by high expression of high-affinity IgE receptor, metachromatic granules, presence of MC granule proteins (Tryptase and Chymase) and activation following substance P stimulation and FcεRI crosslinking. This human iPSC-based approach generates MC precursors and phenotypically mature and functional MC populations. This system will be a useful model to generate human MC populations and broaden our understanding of MC biology and transcriptional regulation of MC differentiation trajectories., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.) more...

Background: Asthma and chronic obstructive pulmonary disease (COPD) are common chronic respiratory diseases, and some patients have overlapping disease features, termed asthma-COPD overlap (ACO). Patients characterized with ACO have increased disease severity; however, the mechanisms driving this have not been widely studied., Objectives: This study sought to characterize the phenotypic and transcriptomic features of experimental ACO in mice induced by chronic house dust mite antigen and cigarette smoke exposure., Methods: Female BALB/c mice were chronically exposed to house dust mite antigen for 11 weeks to induce experimental asthma, cigarette smoke for 8 weeks to induce experimental COPD, or both concurrently to induce experimental ACO. Lung inflammation, structural changes, and lung function were assessed. RNA-sequencing was performed on separated airway and parenchyma lung tissues to assess transcriptional changes. Validation of a novel upstream driver SPI1 in experimental ACO was assessed using the pharmacological SPI1 inhibitor, DB2313., Results: Experimental ACO recapitulated features of both asthma and COPD, with mixed pulmonary eosinophilic/neutrophilic inflammation, small airway collagen deposition, and increased airway hyperresponsiveness. Transcriptomic analysis identified common and distinct dysregulated gene clusters in airway and parenchyma samples in experimental asthma, COPD, and ACO. Upstream driver analysis revealed increased expression of the transcription factor Spi1. Pharmacological inhibition of SPI1 using DB2313, reduced airway remodeling and airway hyperresponsiveness in experimental ACO., Conclusions: A new experimental model of ACO featuring chronic dual exposures to house dust mite and cigarette smoke mimics key disease features observed in patients with ACO and revealed novel disease mechanisms, including upregulation of SPI1, that are amenable to therapy., (Copyright © 2022 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.) more...

Although aging and lung injury are linked to the development of idiopathic pulmonary fibrosis (IPF), the underlying pathognomonic processes predisposing to fibrotic lesions remain largely unknown. A deficiency in the ability of type 2 alveolar epithelial cell (AEC2) progenitors to regenerate and repair the epithelia has been proposed as a critical factor. In this issue of the JCI, Liang et al. identify a deficiency in the zinc transporter SLC39A8 (ZIP8) in AEC2s and in the subsequent activation of the sirtuin SIRT1 that predisposes to decreased AEC2 renewal capacity and enhanced lung fibrosis in both IPF and aging lungs. Interestingly, the authors demonstrate the efficacy of modulating dietary zinc levels, suggesting the need for clinical trials to evaluate the therapeutic potential of dietary supplementation and the development of pharmacological modulation of the Zn/ZIP8/SIRT1 axis for treatment. more...

Importance: There is a lack of studies comparing the intended and unintended consequences of prospective review and feedback (PRF) with computerized decision support systems (CDSS), especially in the longer term in antimicrobial stewardship., Objective: To examine the outcomes associated with the sequential implementation of PRF and CDSS and changes to these interventions with long-term use of antibiotics for and incidence of multidrug resistant organisms (MDROs) and other unintended outcomes., Design, Setting, and Participants: This cohort study used an interrupted time series with segmented regression analysis of data from January 2007 to December 2018. Data were extracted from the electronic medical records of patients admitted at a large university teaching hospital with high rates of antibiotic resistance in Singapore. Data were analyzed from June 2019 to June 2020., Exposures: PRF of piperacillin-tazobactam and carbapenems (intervention 1, April 2009), with the addition of hospital-wide CDSS (intervention 2, April 2011), and lifting of CDSS for half of the hospital wards for 6 months (intervention 3, March 2017)., Main Outcomes and Measures: Monthly antimicrobial use was measured in defined daily doses (DDDs) per 1000 patient-days. The monthly incidence of MDROs was calculated as number of clinical isolates detected per 1000 inpatient-days over a 6-month period. Unintended outcomes examined included in-hospital mortality and age-adjusted length of stay (LOS)., Results: The number of inpatients increased from 56 263 in 2007 to 63 572 in 2018. During the same period, the mean monthly patient days increased from 33 929 in 2007 to 45 603 in 2018, and the proportion of patients older than 65 years increased from 45.5% in 2007 to 56.6% in 2018. After intervention 1, there were 0.33 (95% CI, 0.18 to 0.48) more DDDs per 1000 patient-days per month of piperacillin-tazobactam and carbapenems and -11.05 (95% CI, -15.55 to -6.55) fewer DDDs per 1000 patient-days per month for other broad-spectrum antibiotics. After intervention 2, there were -0.22 (95% CI, -0.33 to -0.10) fewer DDDs per 1000 patient-days per month of piperacillin-tazobactam and carbapenems and -2.10 (95% CI, -3.13 to -1.07) fewer DDDs per 1000 patient-days per month for other broad-spectrum antibiotics. After intervention 3, use of piperacillin-tazobactam and carbapenem increased by 0.28 (95% CI, 0.02 to 0.55) DDDs per 1000 patient-days per month. After intervention 2, incidence of Clostridioides difficile decreased (estimate, -0.02 [95% CI, -0.03 to -0.01] cases per 1000 patient-days per month)., Conclusions and Relevance: In this cohort study, concurrent PRF and CDSS were associated with limiting the use of piperacillin-tazobactam and carbapenems while reducing use of other antibiotics. more...

Background: COVID-19 imposes challenges in antibiotic decision-making due to similarities between bacterial pneumonia and moderate to severe COVID-19. We evaluated the effects of antibiotic therapy on the clinical outcomes of COVID-19 pneumonia patients and diagnostic accuracy of key inflammatory markers to inform antibiotic decision-making., Methods: An observational cohort study was conducted in patients hospitalised with COVID-19 at the National Centre for Infectious Diseases and Tan Tock Seng Hospital, Singapore, from January to April 2020. Patients were defined as receiving empiric antibiotic treatment for COVID-19 if started within 3 days of diagnosis., Results: Of 717 patients included, 86 (12.0%) were treated with antibiotics and 26 (3.6%) had documented bacterial infections. Among 278 patients with COVID-19 pneumonia, those treated with antibiotics had more diarrhoea (26, 34.7% vs. 24, 11.8%, p < 0.01), while subsequent admissions to the intensive care unit were not lower (6, 8.0% vs. 10, 4.9% p = 0.384). Antibiotic treatment was not independently associated with lower 30-day (adjusted odds ratio, aOR 19.528, 95% confidence interval, CI 1.039-367.021) or in-hospital mortality (aOR 3.870, 95% CI 0.433-34.625) rates after adjusting for age, co-morbidities and severity of COVID-19 illness. Compared to white cell count and procalcitonin level, the C-reactive protein level had the best diagnostic accuracy for documented bacterial infections (area under the curve, AUC of 0.822). However, the sensitivity and specificity were less than 90%., Conclusion: Empiric antibiotic use in those presenting with COVID-19 pneumonia did not prevent deterioration or mortality. More studies are needed to evaluate strategies to diagnose bacterial co-infections in these patients. more...

CD4 + T-helper 22 (Th22) cells are a phenotypically distinct lymphocyte subset that produces high levels of interleukin (IL)-22 without co-production of IL-17A. However, the developmental origin and lineage classification of Th22 cells, their interrelationship to Th17 cells, and potential for plasticity at sites of infection and inflammation remain largely undefined. An improved understanding of the mechanisms underpinning the outgrowth of Th22 cells will provide insights into their regulation during homeostasis, infection, and disease. To address this knowledge gap we generated 'IL-17A-fate-mapping IL-17A/IL-22 reporter transgenic mice' and show that Th22 cells develop in the gastrointestinal tract and lung during bacterial infection without transitioning via an Il17a-expressing intermediate, although in some compartments alternative transition pathways exist. Th22-cell development was not dependent on T-bet; however, this transcription factor functioned as a promiscuous T-cell-intrinsic regulator of IL-17A and IL-22 production, in addition to regulating the outgrowth, phenotypic stability, and plasticity of Th22 cells. Thus, we demonstrate that at sites of mucosal bacterial infection Th22 cells develop as a distinct lineage independently of Th17 cells; though both lineages exhibit bidirectional phenotypic flexibility within infected tissues and their draining lymph nodes, and that T-bet plays a critical regulatory role in Th22-cell function and identity., (© 2021. The Author(s), under exclusive licence to Society for Mucosal Immunology.) more...

Background: Redundancy is mostly conceived as "waste" resulting from inefficient operations that ought to be eliminated. However, there are scholars who challenge this view and argue that redundancy is an essential element in facilitating reliable and safe operations in health care delivery processes. The ambiguity on redundancy has led to limited insights in health care settings., Purpose: This article seeks to provide clarity by investigating the conceptualization of redundancy within and across disparate contexts within hospital operations., Design/methodology/approach: An exploratory study using different hospital departments was conducted in two large hospitals as case studies to allow for in-depth understanding of the conceptualization of redundancy across hospital departments. Data sources included 42 semistructured interviews, surveys, field notes from site observations, and document analysis., Results/findings: The findings revealed alternative conceptualizations of redundancy, these being safety, care, heterogeneity, sustenance, and waste, and highlight their dominance in distinct hospital departments. The first four categories are positive in connotation, whereas the last, waste, has a negative connotation. Further, the analysis revealed that the conceptualization of redundancy is context dependent., Conclusion: Contrary to the general cognition of redundancy in the social science and management literature, our research found that redundancy might have a valuable role to play in core health care management concerns such as patient-centeredness, patient safety, and quality of care. This work is one of the first comprehensive studies on redundancy in the health care settings and is expected to steer scholarly conversations on redundancy in a more positive light., Practical Implications: Overall, this article serves as a call to health care operations decision makers and chiefs of hospitals to reexamine their current approach and management practices on redundancy., (Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.) more...

Allergic asthma is a chronic inflammatory airway disease characterized by dysregulated type 2 immune responses, including degranulating airway eosinophils that induce tissue damage and airway hyperresponsiveness (AHR). The type 2 cytokines interleukin 5 (IL-5) and IL-13 and the eosinophil-specific chemokine CCL11/CCL24/CCL26 axis recruit, activate, and regulate eosinophils in the airways. In this issue of the JCI, Karcz et al. identified a mechanism involving the nucleotide sugar UDP-glucose (UDP-G) and the purinergic receptor P2Y14R in amplifying eosinophil accumulation in the lung. During type 2 inflammation, UDP-G activates P2Y14R on eosinophils, inducing the cells to move and migrate into the lung. Pharmacologically or genetically inhibiting P2Y14R on eosinophils attenuated eosinophil infiltration and AHR. Future experiments, including identifying additional type 2 factors regulating P2Y14R expression on lung eosinophils, are necessary to ascertain the impact of targeting P2Y14R as an alternative or adjunctive therapy to current type 2 biologics for the treatment of asthma. more...

Background: Earlier studies have reported high antibiotic use in patients hospitalised for coronavirus disease 2019 (COVID-19), resulting in concerns of increasing antimicrobial resistance with increase antibiotic use in this pandemic. Point prevalence survey (PPS) can be a quick tool to provide antibiotic prescribing information to aid antimicrobial stewardship (AMS) activities., Objectives: To describe antibiotic utilization and evaluate antibiotic appropriateness in COVID-19 patients using PPS., Methods: Adapting Global-PPS on antimicrobial use, the survey was conducted in COVID-19 wards at 2 centres in Singapore on 22 April 2020 at 0800h. Patients on systemic antibiotics were included and evaluated for antibiotic appropriateness., Results: Five hundred and seventy-seven patients were screened. Thirty-six (6.2%) patients were on antibiotics and which were started at median of 7 days (inter-quartile rate (IQR), 4, 11) from symptom onset. Fifty-one antibiotics were prescribed in these patients. Overall, co-amoxiclav (26/51, 51.0%) was the most often prescribed antibiotic. Thirty-one out of 51 (60.8%) antibiotic prescriptions were appropriate. Among 20 inappropriate prescriptions, 18 (90.0%) were initiated in patients with low likelihood of bacterial infections. Antibiotic prescriptions were more appropriate when reviewed by infectious diseases physicians (13/31 [41.9%] versus 2/20 [10.0%], p=0.015), and if reasons for use were stated in notes (31/31 [100.0%] versus 16/20 [80.0%], p=0.019)., Conclusions: Despite low prevalence of antibiotic use among confirmed and suspected COVID-19 patients at 2 centres in Singapore, there was significant proportion of inappropriate antibiotics use where bacterial infections were unlikely. AMS teams can tailor stewardship strategies using PPS results., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.) more...

Background: The deployment of antimicrobial stewardship (AMS) teams to deal with the COVID-19 pandemic can lead to a loss of developed frameworks, best practices and leadership resulting in adverse impact on antimicrobial prescribing and resistance. We aim to investigate effects of reduction in AMS resources during the COVID-19 pandemic on antimicrobial prescribing., Methods: One of 5 full-time equivalent AMS pharmacists was deployed to support pandemic work and AMS rounds with infectious disease physicians were reduced from 5 to 2 times a week. A survey in acute inpatients was conducted using the Global Point Prevalence Survey methodology in July 2020 and compared with those in 2015 and 2017-2019., Results: The prevalence of antimicrobial prescribing (55% in 2015 to 49% in 2019 and 47% in 2020, p = 0.02) and antibacterials (54% in 2015 to 45% in 2019 and 42% in 2020, p < 0.01) have been reducing despite the pandemic. Antimicrobial prescribing in infectious disease wards with suspected or confirmed COVID-19 cases was 29% in 2020. Overall, antimicrobial prescribing quality indicators continued to improve (e.g. reasons in notes, 91% in 2015 to 94% in 2019 and 97% in 2020, p < 0.01) or remained stable (compliance to guideline, 71% in 2015 to 62% in 2019 and 73% in 2020, p = 0.08)., Conclusion: During the COVID-19 pandemic, there was no increase in antimicrobial prescribing and no significant differences in antimicrobial prescribing quality indicators. more...

Background: The anti-inflammatory effect of an α7nAChR agonist, PNU-282987, has previously been explored in the context of inflammatory disease. However, the effects of PNU-282987 on type 2 innate lymphoid cells (ILC2s)-mediated allergic airway inflammation has not yet been established., Aims: To determine the effects of PNU-282987 on the function of ILC2s in the context of IL-33- or Alternaria Alternata (AA)- induced airway inflammation., Methods: PNU-282987 was administered to mice that received recombinant IL-33 or AA intranasal challenges. Lung histological analysis and flow cytometry were performed to determine airway inflammation and the infiltration and activation of ILC2s. The previously published α7nAChR agonist GTS-21 was employed as a comparable reagent. ILC2s were isolated from murine lung tissue and cultured in vitro in the presence of IL-33, IL-2, and IL-7 with/without either PNU-282987 or GTS-21. The expression of the transcription factors GATA3, IKK, and NF-κB were also determined., Results: PNU-282987 and GTS-21 significantly reduced goblet cell hyperplasia in the airway, eosinophil infiltration, and ILC2s numbers in BALF, following IL-33 or AA challenge. In vitro IL-33 stimulation of isolated lung ILC2s showed a reduction of GATA3 and Ki67 in response to PNU-282987 or GTS-21 treatments. There was a significant reduction in IKK and NF-κB phosphorylation in the PNU-282987-treated group when compared to the GTS-21-treated ILC2s., Conclusion: PNU-282987 inhibits ILC2-associated airway inflammation, where its effects were comparable to that of GTS-21., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Yuan, Jiang, Li, Sokulsky, Wanyan, Wang, Liu, Zhou, Tay, Zhang, Yang and Li.) more...

The human microbiome comprises a complex ecosystem of microbial communities that exist within the human body, the largest and most diverse of which are found within the human intestine. It has been increasingly implicated in human health and diseases, demonstrably playing a critical role in influencing host immune response, protection against pathogen overgrowth, biosynthesis, and metabolism. As our understanding of the links between the gut microbiota with host immunity and infectious diseases deepens, there is a greater need to incorporate methods of modulating it as a means of therapy or infection prevention in daily clinical practice. Traditional antimicrobial stewardship principles have been evaluated to assess their impact on the gut microbiota diversity and the consequent repercussions, taking into consideration antibiotic pharmacokinetic and pharmacodynamic properties. Novel strategies of selective digestive decontamination and fecal microbiota transplantation to regulate the gut microbiota have also been tested in different conditions with variable results. This review seeks to provide an overview of the available literature on the modulation of the gut microbiota and its implications for infection control and antimicrobial stewardship. With increased understanding, gut microbiota profiling through metataxonomic analysis may provide further insight into modulating microbial communities in the context of infection prevention and control. more...

Asthma is now recognised as a heterogenous inflammatory disease of the lung based on cellular infiltrates and transcriptional profiles of blood and airway cells. Four distinct subgroups have been defined, eosinophilic (T2), neutrophilic (T1), mixed eosinophilic/neutrophilic and paucigranulocytic. Patients can also be stratified at a molecular level into T2-high, T2-low and/or T1 based on their gene signatures. Current treatments for asthma have been centred on administration of steroids and/or bronchodilators for the relief of bronchoconstriction and inflammation. These treatments are not always effective and often have limited efficacy during exacerbations. Eosinophil expansion and homing to tissues, bronchoconstriction, IgE production and mucus hypersecretion (hallmark features of asthma) are regulated by the type 2 cytokines IL-4, IL-5 and IL-13, the latter of which can induce the expression of the eosinophil chemotactic factors CCL11 and CCL24. A number of new generation biologics (monoclonal antibodies) targeting pathways regulated by the T2 cytokines IL-5 and IL-4/13 (IL-4 receptor alpha) have yielded effective therapies for eosinophil induced exacerbations of severe asthma. Despite these advances, difficulties still remain in treating all exacerbations, and this may reflect the contribution of other inflammatory cells such as neutrophils to pathogenesis. This review describes the effectiveness of targeting T2 pathways, emerging approaches and identifies the potential next steps for therapeutic intervention., (Copyright © 2020. Published by Elsevier Ltd.) more...

Background: Prospective review and feedback (PRF) of antibiotic prescriptions and compulsory computerized decision support system (CDSS) are 2 strategies of antimicrobial stewardship. There are limited studies investigating their combined effects. We hypothesized that the use of on-demand (voluntary) CDSS would achieve similar patient outcomes compared with automatically triggered (compulsory) CDSS whenever broad-spectrum antibiotics are ordered., Methods: A parallel-group, 1:1 block cluster randomized crossover study was conducted in 32 medical and surgical wards from March to August 2017. CDSS use for piperacillin-tazobactam or carbapenem in the intervention clusters was at the demand of the doctor, while in the control clusters CDSS use was compulsory. PRF was continued for both arms. The primary outcome was 30-day mortality., Results: Six hundred forty-one and 616 patients were randomized to voluntary and compulsory CDSS, respectively. There were no differences in 30-day mortality (hazard ratio [HR], 0.87; 95% CI, 0.67-1.12), re-infection and re-admission rates, antibiotic duration, length of stay, or hospitalization cost. The proportion of patients receiving PRF recommendations was not significantly lower in the voluntary CDSS arm (62 [10%] vs 81 [13%]; P = .05). Appropriate indication of antibiotics was high in both arms (351/448 [78%] vs 330/433 [74%]; P = .18). However, in geriatric medicine patients where antibiotic appropriateness was <50%, prescription via compulsory CDSS resulted in a shorter length of stay and lower hospitalization cost., Conclusions: Voluntary broad-spectrum antibiotics with PRF via CDSS did not result in differing clinical outcomes, antibiotic duration, or length of stay. However, in the setting of low antibiotic appropriateness, compulsory CDSS may be beneficial., (© The Author(s) 2020. Published by Oxford University Press on behalf of Infectious Diseases Society of America.) more...

Accumulating evidence highlights links between iron regulation and respiratory disease. Here, we assessed the relationship between iron levels and regulatory responses in clinical and experimental asthma.We show that cell-free iron levels are reduced in the bronchoalveolar lavage (BAL) supernatant of severe or mild-moderate asthma patients and correlate with lower forced expiratory volume in 1 s (FEV 1 ). Conversely, iron-loaded cell numbers were increased in BAL in these patients and with lower FEV 1 /forced vital capacity (FVC) ratio. The airway tissue expression of the iron sequestration molecules divalent metal transporter 1 ( DMT1 ) and transferrin receptor 1 ( TFR1 ) are increased in asthma, with TFR1 expression correlating with reduced lung function and increased Type-2 (T2) inflammatory responses in the airways. Furthermore, pulmonary iron levels are increased in a house dust mite (HDM)-induced model of experimental asthma in association with augmented Tfr1 expression in airway tissue, similar to human disease. We show that macrophages are the predominant source of increased Tfr1 and Tfr1 + macrophages have increased Il13 expression. We also show that increased iron levels induce increased pro-inflammatory cytokine and/or extracellular matrix (ECM) responses in human airway smooth muscle (ASM) cells and fibroblasts ex vivo and induce key features of asthma in vivo , including airway hyper-responsiveness (AHR) and fibrosis, and T2 inflammatory responses.Together these complementary clinical and experimental data highlight the importance of altered pulmonary iron levels and regulation in asthma, and the need for a greater focus on the role and potential therapeutic targeting of iron in the pathogenesis and severity of disease., Competing Interests: Conflict of interest: M.K. Ali has nothing to disclose. Conflict of interest: R.Y. Kim has nothing to disclose. Conflict of interest: A.C. Brown has nothing to disclose. Conflict of interest: J.R. Mayall has nothing to disclose. Conflict of interest: R. Karim has nothing to disclose. Conflict of interest: J.W. Pinkerton has nothing to disclose. Conflict of interest: G. Liu has nothing to disclose. Conflict of interest: K.L. Martin has nothing to disclose. Conflict of interest: M.R. Starkey has nothing to disclose. Conflict of interest: A.L. Pillar has nothing to disclose. Conflict of interest: C. Donovan has nothing to disclose. Conflict of interest: P.S. Pathinayake has nothing to disclose. Conflict of interest: O.R. Carroll has nothing to disclose. Conflict of interest: D. Trinder has nothing to disclose. Conflict of interest: H.L. Tay has nothing to disclose. Conflict of interest: Y.E. Badi has nothing to disclose. Conflict of interest: N.Z. Kermani has nothing to disclose. Conflict of interest: Y-K. Guo has nothing to disclose. Conflict of interest: R. Aryal has nothing to disclose. Conflict of interest: S. Mumby has nothing to disclose. Conflict of interest: S. Pavlidis has nothing to disclose. Conflict of interest: I.M. Adcock reports grants from EU-IMI, during the conduct of the study. Conflict of interest: J. Weaver has nothing to disclose. Conflict of interest: D. Xenaki has nothing to disclose. Conflict of interest: B.G. Oliver has nothing to disclose. Conflict of interest: E.G. Holliday has nothing to disclose. Conflict of interest: P.S. Foster has nothing to disclose. Conflict of interest: P.A. Wark has nothing to disclose. Conflict of interest: D.M. Johnstone has nothing to disclose. Conflict of interest: E.A. Milward has nothing to disclose. Conflict of interest: P.M. Hansbro has nothing to disclose. Conflict of interest: J.C. Horvat has nothing to disclose., (Copyright ©ERS 2020.) more...

Background: Acute exacerbations of asthma represent a major burden of disease and are often caused by respiratory infections. Viral infections are recognized as significant triggers of exacerbations; however, less is understood about the how microbial bioproducts such as the endotoxin (lipopolysaccharide (LPS)) trigger episodes. Indeed, increased levels of LPS have been linked to asthma onset, severity and steroid resistance., Objective: The goal of this study was to identify mechanisms underlying bacterial-induced exacerbations by employing LPS as a surrogate for infection., Methods: We developed a mouse model of LPS-induced exacerbation on the background of pre-existing type-2 allergic airway disease (AAD)., Results: LPS-induced exacerbation was characterized by steroid-resistant airway hyperresponsiveness (AHR) and an exaggerated inflammatory response distinguished by increased numbers of infiltrating neutrophils/macrophages and elevated production of lung inflammatory cytokines, including TNFα, IFNγ, IL-27 and MCP-1. Expression of the type-2 associated inflammatory factors such as IL-5 and IL-13 were elevated in AAD but not altered by LPS exposure. Furthermore, AHR and airway inflammation were no longer suppressed by corticosteroid (dexamethasone) treatment after LPS exposure. Depletion of pulmonary macrophages by administration of 2-chloroadenosine into the lungs suppressed AHR and reduced IL-13, TNFα and IFNγ expression. Blocking IL-13 function, through either IL-13-deficiency or administration of specific blocking antibodies, also suppressed AHR and airway inflammation., Conclusions & Clinical Relevance: We present evidence that IL-13 and innate immune pathways (in particular pulmonary macrophages) contribute to LPS-induced exacerbation of pre-existing AAD and provide insight into the complex molecular processes potentially underlying microbial-induced exacerbations., (© 2019 John Wiley & Sons Ltd.) more...

Severe Clostridioides difficile infection (CDI) is associated with poorer outcomes. We aimed to identify risk factors and treatment outcomes of severe CDI. This was a retrospective cohort study. Eligible patients from January to December 2012 were recruited. Severity definitions were in accordance with SHEA/IDSA 2010 guideline. Treatment outcomes were (1) diarrhoea persistence, (2) CDI recurrence, (3) major complications despite treatment and (4) 30-day mortality. Two hundred and seventy-two patients were included and 40% had severe CDI. High APACHE II score (aOR 1.112, 95% CI 1.014-1.219; p < 0.05), high C-reactive protein (aOR 1.011; 95% CI 1.004-1.019; p < 0.01) and carbapenem usage in past 90 days (aOR 3.259; 95% CI 1.105-9.609; p < 0.05) were independent risk factors of severe CDI. Majority received oral metronidazole as sole treatment (92.6% for mild-moderate, 83.9% for severe, 77% for severe-complicated). Diarrhoea persistence was 32% versus 50% (p < 0.01), CDI recurrence 16.6% versus 16.5% (p > 0.05), major complications 1.2% versus 11% (p < 0.001) and 30-day mortality 7.4% versus 20.2% (p < 0.01) in mild-moderate CDI and severe CDI groups respectively. Oral metronidazole for severe CDI was associated with persistent diarrhoea, major complications and mortality. Risk factors for severe CDI can guide doctors in diagnosing severe CDI earlier and instituting oral vancomycin treatment to improve outcomes from severe CDI. more...

Background: Surgical management of aortic arch pathologies is complex, and endovascular developments have now enabled total or hybrid endovascular aortic arch repair. We present our early experience with fenestrated aortic arch repairs in Ishimaru zones 1 and 2 pathologies., Methods: In a single tertiary institution, all consecutive endovascular aortic arch repairs were reviewed. A preoperative computed tomography aortogram was performed to assess anatomic suitability, which we defined as having a proximal sealing zone with a maximum diameter of 38 mm and minimum length of 20 mm, absence of significant aortic tortuosity, and suitable sealing zones in target vessels., Results: From September 2015 to February 2018, 5 cases of fenestrated aortic arch endovascular repairs were performed. There were 3 male patients. The patients were between 57 and 83 years old, all of whom were American Society of Anesthesiologists (ASA) class II or III. Indications for surgery included aortic arch aneurysms (n = 3), a symptomatic aortic dissection, and a left subclavian artery aneurysm. Three patients had a scallop to the innominate artery, and one patient had a scallop to the left common carotid artery. Fenestrations were made to 3 left common carotid arteries and 3 left subclavian arteries. In 2 patients, a left carotid-subclavian bypass was performed, and the left subclavian artery origin occluded with a vascular plug. Technical success was 100%. One patient developed a right occipital infarct and acute myocardial infarction. The mean duration of surgery was 164 min, and the mean length of stay was 4.2 days. The mean follow-up period was 14.4 months., Conclusions: The use of fenestrated grafts in the aortic arch is a feasible treatment option. However, certain limitations still exist, and preoperative planning is important in ensuring clinical success. Although this procedure appears feasible in the short term, long-term results and durability remain to be seen., (Copyright © 2018 Elsevier Inc. All rights reserved.) more...

Inflammatory bowel disease (IBD) is associated with several immune-mediated extraintestinal manifestations. More than half of all IBD patients have some form of respiratory pathology, most commonly neutrophil-mediated diseases, such as bronchiectasis and chronic bronchitis. Using murine models of colitis, we aimed to identify the immune mechanisms driving pulmonary manifestations of IBD. We found increased neutrophil numbers in lung tissue associated with the pulmonary vasculature in both trinitrobenzenesulfonic acid- and dextran sulfate sodium-induced models of colitis. Analysis of systemic inflammation identified that neutrophilia was associated with bacteremia and pyrexia in animal models of colitis. We further identified IL-6 as a systemic mediator of neutrophil recruitment from the bone marrow of dextran sulfate sodium animals. Functional inhibition of IL-6 led to reduced systemic and pulmonary neutrophilia, but it did not attenuate established colitis pathology. These data suggest that systemic bacteremia and pyrexia drive IL-6 secretion, which is a critical driver for pulmonary manifestation of IBD. Targeting IL-6 may reduce neutrophil-associated extraintestinal manifestations in IBD patients., (Copyright © 2018 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.) more...

A link between inflammatory disease and bone loss is now recognized. However, limited data exist on the impact of virus infection on bone loss and regeneration. Bone loss results from an imbalance in remodeling, the physiological process whereby the skeleton undergoes continual cycles of formation and resorption. The specific molecular and cellular mechanisms linking virus-induced inflammation to bone loss remain unclear. In the current study, we provide evidence that infection of mice with either lymphocytic choriomeningitis virus (LCMV) or pneumonia virus of mice (PVM) resulted in rapid and substantial loss of osteoblasts from the bone surface. Osteoblast ablation was associated with elevated levels of circulating inflammatory cytokines, including TNF-α, IFN-γ, IL-6, and CCL2. Both LCMV and PVM infections resulted in reduced osteoblast-specific gene expression in bone, loss of osteoblasts, and reduced serum markers of bone formation, including osteocalcin and procollagen type 1 N propeptide. Infection of Rag-1-deficient mice (which lack adaptive immune cells) or specific depletion of CD8 + T lymphocytes limited osteoblast loss associated with LCMV infection. By contrast, CD8 + T cell depletion had no apparent impact on osteoblast ablation in association with PVM infection. In summary, our data demonstrate dramatic loss of osteoblasts in response to virus infection and associated systemic inflammation. Further, the inflammatory mechanisms mediating viral infection-induced bone loss depend on the specific inflammatory condition., (Copyright © 2018 by The American Association of Immunologists, Inc.) more...

Respiratory syncytial virus (RSV) infection induces asthma exacerbations, which leads to worsening of clinical symptoms and may result in a sustained decline in lung function. Exacerbations are the main cause of morbidity and mortality associated with asthma, and significantly contribute to asthma-associated healthcare costs. Although glucocorticoids are used to manage exacerbations, some patients respond to them poorly. The underlying mechanisms associated with steroid-resistant exacerbations remain largely unknown. We have previously established a mouse model of RSV-induced exacerbation of allergic airways disease, which mimics hallmark clinical features of asthma. In this study, we have identified key roles for macrophage IFN-γ and IL-27 in the regulation of RSV-induced exacerbation of allergic airways disease. Production of IFN-γ and IL-27 was steroid-resistant, and neutralization of IFN-γ or IL-27 significantly suppressed RSV-induced steroid-resistant airway hyperresponsiveness and airway inflammation. We have previously implicated activation of pulmonary macrophage by TNF-α and/or MCP-1 in the mechanisms of RSV-induced exacerbation. Stimulation of pulmonary macrophages with TNF-α and/or MCP-1 induced expression of both IFN-γ and IL-27. Our findings highlight critical roles for IFN-γ and IL-27, downstream of TNF-α and MCP-1, in the mechanism of RSV-induced exacerbation. Thus, targeting the pathways that these factors activate may be a potential therapeutic approach for virus-induced asthma exacerbations., (Copyright © 2017 by The American Association of Immunologists, Inc.) more...

Introduction: The multi-disciplinary antimicrobial stewardship team at the study hospital conducts prospective review and feedback on all inpatient orders of piperacillin-tazobactam and carbapenems. In addition, the team provides non-antibiotic recommendations (i.e. additional investigations and infectious disease reviews). This study aimed to describe the impact of these recommendations on patient outcomes., Methods: Patients on carbapenem and piperacillin-tazobactam who received at least one non-antibiotic recommendation between January 2012 and August 2014 were included in this study. Acceptance and rejection of non-antibiotic recommendations by the managing physician were compared. The primary outcome was 30-d mortality., Results: Non-antibiotic recommendations were made in 166 patients. There were no differences in baseline characteristics between patients for whom recommendations were accepted and patients for whom recommendations were rejected. Thirty-day mortality (18.0% vs. 34.5%, P = 0.02) was significantly lower in patients who had at least one non-antibiotic recommendation accepted. Multi-variate analysis found that Charlson's comorbidity score [odds ratio (OR) 1.20, 95% confidence interval (CI) 1.03-1.42, P = 0.03], APACHE II score (OR 1.10, 95% CI 1.01-1.19, P < 0.01), hepatobiliary source of infection (OR 10.19, 95% CI 1.44-72.13, P = 0.02) and acceptance of at least one non-antibiotic recommendation (OR 0.39, 95% CI 0.17-0.88, P = 0.02) were independently associated with 30-d mortality., Conclusions: During prospective review and feedback of piperacillin-tazobactam and carbapenems, acceptance of non-antibiotic recommendations was found to be associated with a reduction in 30-d mortality., (Copyright © 2017 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.) more...

Severe asthma has significant disease burden and results in high healthcare costs. While existing therapies are effective for the majority of asthma patients, treatments for individuals with severe asthma are often ineffective. Mouse models are useful to identify mechanisms underlying disease pathogenesis and for the preclinical assessment of new therapies. In fact, existing mouse models have contributed significantly to our understanding of allergic/eosinophilic phenotypes of asthma and facilitated the development of novel targeted therapies (e.g. anti-IL-5 and anti-IgE). These therapies are effective in relevant subsets of severe asthma patients. Unfortunately, non-allergic/non-eosinophilic asthma, steroid resistance and disease exacerbation remain areas of unmet clinical need. No mouse model encompasses all features of severe asthma. However, mouse models can provide insight into pathogenic pathways that are relevant to severe asthma. In this review, as examples, we highlight models relevant to understanding steroid resistance, chronic tissue remodelling and disease exacerbation. Although these models highlight the complexity of the immune pathways that may underlie severe asthma, they also provide insight into new potential therapeutic approaches., (© 2017 Asian Pacific Society of Respirology.) more...

In this review, we highlight experiments conducted in our laboratories that have elucidated functional roles for CD4 + T-helper type-2 lymphocytes (T Hpt> 2 cells), their associated cytokines, and eosinophils in the regulation of hallmark features of allergic asthma. Notably, we consider the complexity of type-2 responses and studies that have explored integrated signaling among classical T H 2 cytokines (IL-4, IL-5, and IL-13), which together with CCL11 (eotaxin-1) regulate critical aspects of eosinophil recruitment, allergic inflammation, and airway hyper-responsiveness (AHR). Among our most important findings, we have provided evidence that the initiation of T H 2 responses is regulated by airway epithelial cell-derived factors, including TRAIL and MID1, which promote T H 2 cell development via STAT6-dependent pathways. Further, we highlight studies demonstrating that microRNAs are key regulators of allergic inflammation and potential targets for anti-inflammatory therapy. On the background of T H 2 inflammation, we have demonstrated that innate immune cells (notably, airway macrophages) play essential roles in the generation of steroid-resistant inflammation and AHR secondary to allergen- and pathogen-induced exacerbations. Our work clearly indicates that understanding the diversity and spatiotemporal role of the inflammatory response and its interactions with resident airway cells is critical to advancing knowledge on asthma pathogenesis and the development of new therapeutic approaches., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.) more...

Th22 cells are a major source of IL-22 and have been found at sites of infection and in a range of inflammatory diseases. However, their molecular characteristics and functional roles remain largely unknown because of our inability to generate and isolate pure populations. We developed a novel Th22 differentiation assay and generated dual IL-22/IL-17A reporter mice to isolate and compare pure populations of cultured Th22 and Th17 cells. Il17a fate-mapping and transcriptional profiling provide evidence that these Th22 cells have never expressed IL-17A, suggesting that they are potentially a distinct cell lineage from Th17 cells under in vitro culture conditions. Interestingly, Th22 cells also expressed granzymes, IL-13, and increased levels of Tbet. Using transcription factor-deficient cells, we demonstrate that RORγt and Tbet act as positive and negative regulators of Th22 differentiation, respectively. Furthermore, under Th1 culture conditions in vitro, as well as in an IFN-γ-rich inflammatory environment in vivo, Th22 cells displayed marked plasticity toward IFN-γ production. Th22 cells also displayed plasticity under Th2 conditions in vitro by upregulating IL-13 expression. Our work has identified conditions to generate and characterize Th22 cells in vitro. Further, it provides evidence that Th22 cells develop independently of the Th17 lineage, while demonstrating plasticity toward both Th1- and Th2-type cells., (Copyright © 2017 by The American Association of Immunologists, Inc.) more...

Limited evidence is available about the specific miRNA networks that regulate differentiation of specific immune cells. In this study, we characterized miRNA expression and associated alterations in expression with putative mRNA targets that are critical during differentiation of macrophages. In an effort to map the dynamic changes in the bone marrow (BM), we profiled whole BM cultures during differentiation into macrophages. We identified 112 miRNAs with expression patterns that were differentially regulated 5-fold or more during BMDM development. With TargetScan and MeSH databases, we identified 1267 transcripts involved in 30 canonical pathways linked to macrophage biology as potentially regulated by these specific 112 miRNAs. Furthermore, by employing miRanda and Ingenuity Pathways Analysis (IPA) analysis systems, we identified 18 miRNAs that are temporally linked to the expression of CSF1R, CD36, MSR1 and SCARB1; 7 miRNAs linked to the regulation of the transcription factors RUNX1 and PU.1, and 14 miRNAs target the nuclear receptor PPARα and PPARγ. This novel information provides an important reference resource for further study of the functional links between miRNAs and their target mRNAs for the regulation of differentiation and function of macrophages., Competing Interests: CONFLICTS OF INTERESTS The authors declare no competing financial interests. more...

MicroRNAs (miRNAs) are short noncoding RNAs that regulate a broad spectrum of biological processes, including immune responses. Although the contributions of miRNAs to the function of immune cells are beginning to emerge, their specific roles remain largely unknown. IL-33 plays an important role in macrophage activation for innate host defense and proinflammatory responses. In this study, we report that miR-487b can suppress the levels of mRNA and protein for IL-33 during the differentiation of bone marrow-derived macrophages (BMDMs). This results in inhibition of IL-33-induced expression of Ag-presenting and costimulatory molecules and proinflammatory mediators. A luciferase assay showed that miR-487b binds to the IL-33 3'-untranslated region. We also confirmed that IL-33 directly promotes the activation of BMDMs by increasing the expression of MHC class I, MHC class II, CD80/CD86, and inducible NO synthase (iNOS) in a dose-dependent manner. Exposure of BMDMs to the TLR4 ligand, LPS, decreased miR-487b expression, increased IL-33 transcript levels, and induced the production of proinflammatory mediators (e.g., iNOS, IL-1β, IL-6, and TNF-α). Treatment with a specific inhibitor of miR-487b function also resulted in increased levels of IL-33 mRNA, which augmented LPS-induced expression of these inflammatory mediators in macrophages. Collectively, our results indicate that miR-487b plays a negative regulatory role in macrophages by controlling the levels of IL-33 transcript and protein to fine-tune innate immune host defense and proinflammatory responses of these cells. Thus, miR-487b plays an important role in the regulation of macrophage homeostasis and activation by targeting IL-33 transcripts., (Copyright © 2016 by The American Association of Immunologists, Inc.) more...

MicroRNAs (miRNAs) are small non-coding RNA molecules that modulate expression of the majority of genes by inhibiting protein translation. Growing literature has identified functional roles for miRNAs across a broad range of biological processes. As such, miRNAs are recognized as potential disease biomarkers and novel targets for therapies. While several miRNA-targeted therapies are currently in clinical trials (e.g., for the treatment of hepatitis C virus infection and cancer), no therapies have targeted miRNAs in respiratory diseases in the clinic. In this mini-review, we review the current knowledge on miRNA expression and function in respiratory diseases, intervention strategies to target miRNA function, and considerations specific to respiratory diseases. Altered miRNA expression profiles have been reported in a number of respiratory diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, and idiopathic pulmonary fibrosis. These include alterations in isolated lung tissue, as well as sputum, bronchoalveolar lavage fluids and peripheral blood or serum. The observed alterations in easily accessible body fluids (e.g., serum) have been proposed as new biomarkers that may inform disease diagnosis and patient management. In a subset of studies, miRNA-targeted interventions also improved disease outcomes, indicating functional roles for altered miRNA expression in disease pathogenesis. In fact, direct administration of miRNA-targeting molecules to the lung has yielded promising results in a number of animal models. The ability to directly administer compounds to the lung holds considerable promise and may limit potential off-target effects and side effects caused by the systemic administration required to treat other diseases. more...