Background Glucocorticoids are used as mainstay therapy for asthma, but some patients remain resistant to therapy. MicroRNAs (miRNAs) are important regulators of the immune system by promoting the ...catabolism of their target transcripts as well as attenuating their translation. The role of miRNA in regulating allergic inflammation remains largely unknown. Blocking miRNA function may provide a new nonsteroidal anti-inflammatory approach to treatment. Objectives To (1) determine the role of specific miRNAs in the regulation of hallmark features of allergic airways inflammation and (2) compare the efficacy of antagonizing miRNA function with that of steroid treatment. Methods Mice were sensitized and then aeroallergen-challenged with house dust mite to induce allergic airways disease, and alterations in the expression of miRNAs were characterized. Next mice were treated with antagomirs that inhibited the function of specific miRNAs in the lung or treated with dexamethasone and inflammatory lesions, and airway hyperresponsiveness was measured. Results miR-145, miR-21, and let-7b have been implicated in airway smooth muscle function, inflammation, and airways epithelial cell function, respectively. Inhibition of miR-145, but not miR-21 or lethal-7b, inhibited eosinophilic inflammation, mucus hypersecretion, TH 2 cytokine production, and airway hyperresponsiveness. The anti-inflammatory effects of miR-145 antagonism were comparable to steroid treatment. Conclusion Our study highlights the importance of understanding the contribution of miRNAs to pathogenesis of human allergic disease and their potential as novel anti-inflammatory targets.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Summary Background Bronchiolitis is the most common lung infection in infants and treatment focuses on management of respiratory distress and hypoxia. High-flow warm humidified oxygen (HFWHO) is ...increasingly used, but has not been rigorously studied in randomised trials. We aimed to examine whether HFWHO provided enhanced respiratory support, thereby shortening time to weaning off oxygen. Methods In this open, phase 4, randomised controlled trial, we recruited children aged less than 24 months with moderate bronchiolitis attending the emergency department of the John Hunter Hospital or the medical unit of the John Hunter Children's Hospital in New South Wales, Australia. Patients were randomly allocated (1:1) via opaque sealed envelopes to HFWHO (maximum flow of 1 L/kg per min to a limit of 20 L/min using 1:1 air–oxygen ratio, resulting in a maximum FiO2 of 0·6) or standard therapy (cold wall oxygen 100% via infant nasal cannulae at low flow to a maximum of 2 L/min) using a block size of four and stratifying for gestational age at birth. The primary outcome was time from randomisation to last use of oxygen therapy. All randomised children were included in the primary and secondary safety analyses. This trial is registered with the Australian New Zealand Clinical Trials Registry, number ACTRN12612000685819. Findings From July 16, 2012, to May 1, 2015, we randomly assigned 202 children to either HFWHO (101 children) or standard therapy (101 children). Median time to weaning was 24 h (95% CI 18–28) for standard therapy and 20 h (95% CI 17–34) for HFWHO (hazard ratio HR for difference in survival distributions 0·9 95% CI 0·7–1·2; log rank p=0·61). Fewer children experienced treatment failure on HFWHO (14 14%) compared with standard therapy (33 33%; p=0·0016); of these children, those on HFWHO were supported for longer than were those on standard therapy before treatment failure (HR 0·3; 95% CI 0·2–0·6; p<0·0001). 20 (61%) of 33 children who experienced treatment failure on standard therapy were rescued with HFWHO. 12 (12%) of children on standard therapy required transfer to the intensive care unit compared with 14 (14%) of those on HFWHO (difference −1%; 95% CI −7 to 16; p=0·41). Four adverse events occurred (oxygen desaturation and condensation inhalation in the HFWHO group, and two incidences of oxygen tubing disconnection in the standard therapy group); none resulted in withdrawal from the trial. No oxygen-related serious adverse events occurred. Secondary effectiveness outcomes are reported in the Results section. Interpretation HFWHO did not significantly reduce time on oxygen compared with standard therapy, suggesting that early use of HFWHO does not modify the underlying disease process in moderately severe bronchiolitis. HFWHO might have a role as a rescue therapy to reduce the proportion of children requiring high-cost intensive care. Funding Hunter Children's Research Foundation, John Hunter Hospital Charitable Trust, and the University of Newcastle Priority Research Centre GrowUpWell.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Inflammation is associated with an increased risk of a range of chronic diseases. A diet high in fruit and vegetables may help to reduce inflammation, as fruit and vegetables are rich sources of ...antioxidants and other biologically active substances, which may improve immune function.
To summarize the evidence, we executed a systematic review and meta-analysis examining the effects of fruit and/or vegetable intake on inflammatory biomarkers and immune cells in humans with different diseases and conditions.
Electronic databases including PubMed, Cochrane, CINAHL, and EMBASE were systematically searched up to March 2018.
Eighty-three studies were included. Of these, 71 (86%) were clinical trials, and 12 were observational studies (n = 10 cross-sectional and n = 2 cohort). Amongst the observational research, n = 10 studies found an inverse association between intakes of fruit or vegetables and inflammatory biomarkers. Similarly, the majority of the intervention studies (68%, n = 48) reported beneficial effects of fruit or vegetable intake on ≥1 biomarker of systemic or airway inflammation. A meta-analysis of included studies showed that fruit or vegetable intake decreased circulating levels of C-reactive protein and tumor necrosis factor-α (P < 0.05) and increased the γδ-T cell population (P < 0.05).
In conclusion, this review suggests that higher intakes of fruit and vegetables lead to both a reduction in proinflammatory mediators and an enhanced immune cell profile.
Full text
Available for:
CMK, GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Allergic asthma is an inflammatory disease of the lung characterized by abnormal T helper-2 (TH2) lymphocyte responses to inhaled antigens. The molecular mechanisms leading to the generation of TH2 ...responses remain unclear, although toll-like receptors (TLRs) present on innate immune cells play a pivotal role in sensing molecular patterns and in programming adaptive T cell responses. Here we show that in vivo activation of TLR4 by house dust mite antigens leads to the induction of allergic disease, a process that is associated with expression of a unique subset of small, noncoding microRNAs. Selective blockade of microRNA (miR)-126 suppressed the asthmatic phenotype, resulting in diminished TH2 responses, inflammation, airways hyperresponsiveness, eosinophil recruitment, and mucus hypersecretion. miR-126 blockade resulted in augmented expression of POU domain class 2 associating factor 1, which activates the transcription factor PU.1 that alters TH2 cell function via negative regulation of GATA3 expression. In summary, this study presents a functional connection between miRNA expression and asthma pathogenesis, and our data suggest that targeting miRNA in the airways may lead to anti-inflammatory treatments for allergic asthma.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Summary
In this review, we highlight experiments conducted in our laboratories that have elucidated functional roles for CD4+ T‐helper type‐2 lymphocytes (TH2 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 TH2 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 TH2 responses is regulated by airway epithelial cell‐derived factors, including TRAIL and MID1, which promote TH2 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 TH2 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.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
Rhinovirus (RV) infections in asthmatic patients are often associated with asthma exacerbation, characterized by worsened airways hyperreactivity and increased immune cell infiltration to the ...airways. The C-X-C chemokines, CXCL3 and CXCL5, regulate neutrophil trafficking to the lung via CXCR2, and their expression in the asthmatic lung is associated with steroid-insensitive type 2 inflammatory signatures. Currently, the role of CXCL3 and CXCL5 in regulating neutrophilic and type 2 responses in viral-induced asthma exacerbation is unknown. Inhibition of CXCL3 or CXCL5 with silencing RNAs in a mouse model of RV-induced exacerbation of asthma attenuated the accumulation of CXCR2
neutrophils, eosinophils, and innate lymphoid cells in the lung and decreased production of type 2 regulatory factors IL-25, IL-33, IL-5, IL-13, CCL11, and CCL24. Suppression of inflammation was associated with decreased airways hyperreactivity, mucus hypersecretion, and collagen deposition. Similar results were obtained by employing RC-3095, which has been shown to bind to CXCR2, or by depletion of neutrophils. Our data demonstrate that CXCL3 and CXCL5 may be critical in the perpetuation of RV-induced exacerbation of asthma through the recruitment of CXCR2-positive neutrophils and by promoting type 2 inflammation. Targeting the CXCL3/CXCL5/CXCR2 axis may provide a new therapeutic approach to attenuating RV-induced exacerbations of asthma.
Asthma exacerbations represent a significant disease burden and are commonly caused by rhinovirus (RV), which is sensed by Toll-like receptors (TLR) such as TLR7. Some asthmatics have impaired ...interferon (IFN) responses to RV, but the underlying mechanisms of this clinically relevant observation are poorly understood.
To investigate the importance of intact TLR7 signalling in vivo during RV exacerbation using mouse models of house dust mite (HDM)-induced allergic airways disease exacerbated by a superimposed RV infection.
Wild-type and TLR7-deficient (Tlr7(-/-)) BALB/c mice were intranasally sensitised and challenged with HDM prior to infection with RV1B. In some experiments, mice were administered recombinant IFN or adoptively transferred with plasmacytoid dendritic cells (pDC).
Allergic Tlr7(-/-) mice displayed impaired IFN release upon RV1B infection, increased virus replication and exaggerated eosinophilic inflammation and airways hyper reactivity. Treatment with exogenous IFN or adoptive transfer of TLR7-competent pDCs blocked these exaggerated inflammatory responses and boosted IFNγ release in the absence of host TLR7 signalling. TLR7 expression in the lungs was suppressed by allergic inflammation and by interleukin (IL)-5-induced eosinophilia in the absence of allergy. Subjects with moderate-to-severe asthma and eosinophilic but not neutrophilic airways inflammation, despite inhaled steroids, showed reduced TLR7 and IFNλ2/3 expression in endobronchial biopsies. Furthermore, TLR7 expression inversely correlated with percentage of sputum eosinophils.
This implicates IL-5-induced airways eosinophilia as a negative regulator of TLR7 expression and antiviral responses, which provides a molecular mechanism underpinning the effect of eosinophil-targeting treatments for the prevention of asthma exacerbations.
Exhaled nitric oxide is a marker of airway inflammation. Air pollution induces airway inflammation and oxidative stress. Little is known about the impact of air pollution on exhaled nitric oxide in ...young infants.
The Breathing for Life Trial recruited pregnant women with asthma into a randomised controlled trial comparing usual clinical care versus inflammometry-guided asthma management in pregnancy. Four hundred fifty-seven infants from the Breathing for Life Trial birth cohort were assessed at six weeks of age. Exhaled nitric oxide was measured in unsedated, sleeping infants. Its association with local mean 24-h and mean seven-day concentrations of ozone, nitric oxide, nitrogen dioxide, carbon monoxide, sulfur dioxide, ammonia, particulate matter less than 10 μm (PM10) and less than 2.5 μm (PM2.5) in diameter was investigated. The air pollutant data were sourced from local monitoring sites of the New South Wales Air Quality Monitoring Network. The association was assessed using a 'least absolute shrinkage and selection operator' (LASSO) approach, multivariable regression and Spearman's rank correlation.
A seasonal variation was evident with higher median exhaled nitric oxide levels (13.6 ppb) in warmer months and lower median exhaled nitric oxide levels (11.0 ppb) in cooler months, P = 0.008. LASSO identified positive associations for exhaled nitric oxide with 24-h mean ammonia, seven-day mean ammonia, seven-day mean PM10, seven-day mean PM2.5, and seven-day mean ozone; and negative associations for eNO with seven-day mean carbon monoxide, 24-h mean nitric oxide and 24-h mean sulfur dioxide, with an R-square of 0.25 for the penalized coefficients. These coefficients selected by LASSO (and confounders) were entered in multivariable regression. The achieved R-square was 0.27.
In this cohort of young infants of asthmatic mothers, exhaled nitric oxide showed seasonal variation and an association with local air pollution concentrations.
Full text
Available for:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The role of microRNAs (miRNAs) in regulating gene expression is currently an area of intense interest. Relatively little is known, however, about the role of miRNAs in inflammatory and ...immunologically-driven disorders. In a mouse model, we have previously shown that miRNAs are potentially important therapeutic targets in allergic asthma, because inhibition of miR-126, one of a small subset of miRNAs upregulated in the airway wall, effectively suppressed Th2-driven airway inflammation and other features of asthma. In the present study, we extended investigation of the therapeutic potential of miRNA inhibition to our well-established model of chronic asthma.
Female BALB/c mice were systemically sensitised with ovalbumin (OVA) and chronically challenged with low mass concentrations of aerosolised OVA for up to 6 weeks. Airway tissue was obtained by blunt dissection and RNA was isolated for miRNA profiling. On the basis of the results obtained, animals were subsequently treated with either an antagomir to miR-126 (ant-miR-126) or a scrambled control antagomir once weekly during the 6 weeks of chronic challenge, and the effects on airway inflammation and remodelling were assessed using established morphometric techniques.
Compared to naïve mice, there was selective upregulation of a modest number of miRNAs, notably miR-126, in the airway wall tissue of chronically challenged animals. The relative increase was maximal after 2 weeks of inhalational challenge and subsequently declined to baseline levels. Compared to treatment with the scrambled control, ant-miR-126 significantly reduced recruitment of intraepithelial eosinophils, but had no effect on the chronic inflammatory response, or on changes of airway remodelling.
In this model of chronic asthma, there was an initial increase in expression of a small number of miRNAs in the airway wall, notably miR-126. However, this later declined to baseline levels, suggesting that sustained changes in miRNA may not be essential for perpetuation of chronic asthma. Moreover, inhibition of miR-126 by administration of an antagomir suppressed eosinophil recruitment into the airways but had no effect on chronic inflammation in the airway wall, or on changes of remodelling, suggesting that multiple miRNAs are likely to regulate the development of these lesions.
Background
Rhinovirus (RV) positive bronchiolitis episodes in infancy confer a higher risk to develop asthma in later childhood with associated lung function impairments. We aimed to investigate the ...association between the type of virus causing a bronchiolitis hospitalization episode and lung ventilation inhomogeneities at preschool age.
Methods
Infants hospitalized with a clinical diagnosis of moderate (ward admission) or severe (pediatric intensive care ward admission) bronchiolitis were prospectively followed‐up at preschool age to assess nitrogen (N2) multiple breath washout (MBW). Lung clearance index (LCI), functional residual capacity (FRC), and concentration normalized phase III slope analysis (SnIII) indices were reported from ≥2 technically acceptable trials. Differences between groups were calculated using logistic and linear regression and adjusted for confounders (sex, age at bronchiolitis admission, height at visit, maternal asthma, and doctor‐diagnosed asthma, including interaction terms between the latter three). An interaction term was included in a regression model to test for an interaction between RV bronchiolitis severity and MBW parameters at preschool age.
Results
One hundred and thirty‐nine subjects attended preschool follow‐up, of which 84 out of 103 (82%) performing MBW had technically acceptable data. Children with a history of RV positive bronchiolitis (n = 39) had increased LCI (adjusted β‐coefficient aβ = 0.33, 95% confidence interval CI 0.02–0.65, p = 0.040) and conductive airways ventilation inhomogeneity Scond (aβ = 0.016, CI 0.004–0.028, p = 0.011) when compared with those with a RV negative bronchiolitis history (n = 45). In addition, we found a statistical interaction between RV bronchiolitis and bronchiolitis severity strengthening the association with LCI (aβ = 0.93, CI 0.20–1.58, p = 0.006).
Conclusion
Children with a history of hospital admission for RV positive bronchiolitis in infancy might be at a higher risk of lung ventilation inhomogeneities at preschool age, arising from the peripheral conducting airways.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
PDF
