Effet of combined nitrogen dioxide and carbon nanoparticle exposure on lung function during ovalbumin sensitization in brown norway rat

International audienceThe interaction of particulate and gaseous pollutants in their effects on the severity of allergic inflammation and airway responsiveness are not well understood. We assessed the effect of exposure to NO2 in the presence or absence of repetitive treatment with carbon nanoparticle (CNP) during allergen sensitization and challenges in Borwn-Norway (BN) rat, in order to assess their interactions on lung function and airway responses (AR) to allergen and methacholine (MCH), end-expiratory lung volume (EELV), bronchoalveolar lavage fluid (BALF) cellular content, serum and BALF cytokine levels and histological changes. Animals were divided into the following groups (n = 6): Control; CNP (Degussa-FW2): 13 nm, 0.5 mg/kg instilled intratracheally ×3 at 7-day intervals; OVA: ovalbumin-sensitised; OVA+CNP: both sensitized and exposed to CNP. Rats were divided into equal groups exposed either to air or to NO2, 10 ppm, 6 h/d, 5d/wk for 4 weeks. Exposure to NO2, significantly enhanced lung inflammation and airway reactivity, with a significantly larger effect in animals sensitized to allergen, which was related to a higher expression of TH1 and TH2-type cytokines. Conversely, exposure to NO2 in animals undergoing repeated tracheal instillation of CNP alone, increased BALF neutrophilia and enhanced the expression of TH1 cytokines: TNF-a and IFN-?, but did not show an additive effect on airway reactivity in comparison to NO2 alone. The exposure to NO2 combined with CNP treatment and allergen sensitization however, unexpectedly resulted in a significant decrease in both airway reactivity to allergen and to methacholine, and a reduction in TH2-type cytokines compared to allergen sensitization alone. EELV was significantly reduced with sensitization, CNP treatment or both. These data suggest an immunomodulatory effect of repeated tracheal instillation of CNP on the proinflammatory effects of NO2 exposure in sensitized BN rat. Furthermore, our findings suggest that NO2, CNP and OVA sensitization may significantly slow overall lung growth in parenchymally mature animals

Food Allergies in Modern Life

Food allergy, a specific immune response that occurs reproducibly upon exposure to a food allergen, is an increasing public health problem, causing a significant burden for affected patients, resulting in dietary restrictions, fear of accidental ingestions and related risk of severe reactions, and reduced quality of life. Clinical presentation ranges from mild to life-threatening symptoms. Component-resolved diagnosis with recombinant allergens has improved the diagnosis and, consequently, clinical management. Currently, there is no specific treatment for food allergy, so the only available management is limited to strict dietary avoidance, education on prompt recognition of symptoms, and emergency treatment of adverse reaction. In parallel, novel knowledge on the pathogenesis of food allergy is opening the way to new trials investigating several allergen-specific and allergen non-specific therapies, aiming to prevent the development of food allergy and acquire a persistent food tolerance

The first wheezing episode and the subsequent risk for asthma

Abstract: Background: The rhinovirus etiology of acute wheezing and allergic sensitization are important risk factors for asthma. Early interventions with oral corticosteroids have shown a possible potential to decrease asthma risk in some rhinovirus affected subgroups. However, information about the first wheezing episode overall and the effect of the risk factors diagnosed during the first wheezing episode on asthma development and lung function remain limited. Aims: The aims of this thesis were to study 1) the virus etiology of the first severe wheezing episode and the associations among the virus etiology, atopic characteristics and vitamin D status; 2) the efficacy of prednisolone during the first severe wheezing episode concerning the time to initiation of asthma control medication and 3) lung function 4 years after the first severe wheezing episode. Methods: In children aged 3-23 months, virus etiology and patient characteristics of the first wheezing episode were studied using laboratory diagnostics, standard parental questionnaires and patient charts. The efficacy of prednisolone was studied in a randomized placebo-controlled trial. During a 4-year follow-up using impulse oscillometry with exercise and bronchodilation tests, lung function was investigated. Results: Rhinovirus was the most common etiology (76%) of the first wheezing episode and positively associated with atopic characteristics and prolonged coughing. Vitamin D levels of the children were normal and were not associated with virus etiology or atopic characteristics. Children with a high rhinovirus genome load benefitted from prednisolone in terms of longer time to initiation of asthma control medication. Early allergic sensitization was associated with increased airway reactivity at preschool age. Conclusions: Rhinovirus is a common etiologic agent in the first severe wheezing episode and linked to atopic characteristics. These findings about the efficacy of prednisolone create a basis for planning the early intervention strategies to secondary prevention of asthma. Diagnosing allergic sensitization early is important for predicting the risk of asthma and compromised lung function development.Tiivistelmä: Tausta: Rinoviruksen aiheuttama uloshengitysvaikeuskohtaus ja allerginen herkistyminen ovat merkittäviä astman ennaltaehkäisyssä. Jotkin potilasryhmät saattavat hyötyä varhaisessa vaiheessa suun kautta annetusta kortikosteroidilääkityksestä. Ensimmäistä akuuttia uloshengitysvaikeutta ja sen aikaisten riskitekijöiden vaikutusta keuhkojen toimintaan ja astmaan on kuitenkin tutkittu vasta vähän. Tavoitteet: Tämän väitöstutkimuksen tavoitteena oli tutkia 1) ensimmäisen vaikean uloshengitysvaikeuskohtauksen virusetiologiaa sekä virusetiologian, atooppisten tekijöiden ja D-vitamiinitason keskinäisiä yhteyksiä; 2) ensimmäisen kohtauksen aikana annetun prednisolonilääkityksen vaikutusta astman kehittymiseen ja 3) keuhkojen toimintaa neljä vuotta ensimmäisen kohtauksen jälkeen. Menetelmät: Ensimmäisestä uloshengitysvaikeuskohtauksesta kärsivien 3-23 kuukauden ikäisten lasten atooppisia ominaisuuksia ja taudin virusetiologiaa sekä taudin vaikeusastetta selvitettiin laboratoriokokein, kyselykaavakkein ja sairauskertomuksia hyödyntäen. Prednisolonin tehoa tutkittiin satunnaistetulla, kontrolloidulla tutkimuksella. Keuhkojen toimintaa tutkittiin neljän vuoden kuluttua oskillometriatutkimuksella. Tulokset: Rinovirus oli yleisin virus (76 %) ensimmäisessä uloshengitysvaikeuskohtauksessa ja se oli yhteydessä atooppisiin ominaisuuksiin ja pidentyneeseen yskään. D-vitamiinitaso lapsilla oli normaali eikä se ollut yhteydessä atooppisiin tekijöihin tai virusetiologiaan. Lapset, joilla rinoviruksen määrä hengitysteissä oli suuri, hyötyivät prednisolonihoidosta kun vasteena tarkasteltiin aikaa astmalääkityksen aloitukseen. Varhain diagnosoitu allerginen herkistyminen oli yhteydessä lisääntyneeseen keuhkoputkien reaktiivisuuteen leikki-ikäisenä. Johtopäätökset: Rinovirus on yleinen löydös ensimmäisestä vaikeasta uloshengitysvaikeuskohtauksesta kärsivillä lapsilla ja se on yhteydessä atooppisiin tekijöihin. Löydökset prednisolonin tehosta luovat pohjaa riskiryhmien astman estämiseen tähtäävien interventiotutkimusten suunnittelulle. Allergisen herkistymisen varhainen diagnosointi on tärkeää, jotta voidaan ennustaa astmariskiä ja keuhkofunktion kehittymistä

Rhinovirus exacerbates house-dust-mite induced lung disease in adult mice

Abstract Human rhinovirus is a key viral trigger for asthma exacerbations. To date, murine studies investigating rhinovirus-induced exacerbation of allergic airways disease have employed systemic sensitisation/intranasal challenge with ovalbumin. In this study, we combined human-rhinovirus infection with a clinically relevant mouse model of aero-allergen exposure using house-dust-mite in an attempt to more accurately understand the links between human-rhinovirus infection and exacerbations of asthma. Adult BALB/c mice were intranasally exposed to low-dose house-dust-mite (or vehicle) daily for 10 days. On day 9, mice were inoculated with human-rhinovirus-1B (or UV-inactivated human-rhinovirus-1B). Forty-eight hours after inoculation, we assessed bronchoalveolar cellular inflammation, levels of relevant cytokines/serum antibodies, lung function and responsiveness/sensitivity to methacholine. House-dust-mite exposure did not result in a classical TH 2 -driven response, but was more representative of noneosinophilic asthma. However, there were significant effects of house-dustmite exposure on most of the parameters measured including increased cellular inflammation (primarily macrophages and neutrophils), increased total IgE and house-dust-mite-specific IgG 1 and increased responsiveness/sensitivity to methacholine. There were limited effects of human-rhinovirus-1B infection alone, and the combination of the two insults resulted in additive increases in neutrophil levels and lung parenchymal responses to methacholine (tissue elastance). We conclude that acute rhinovirus infection exacerbates house-dust-mite-induced lung disease in adult mice. The similarity of our results using the naturally occurring allergen house-dust-mite, to previous studies using ovalbumin, suggests that the exacerbation of allergic airways disease by rhinovirus infection could act via multiple or conserved mechanisms

Defining the role of mast cells in guinea pig models of asthma

Asthma is a common respiratory disease characterized by several pathophysiological features, such as allergen induced bronchoconstriction (in allergic asthma), airway hyperresponsiveness (AHR), airway inflammation, airway remodeling and mast cell hyperplasia. An increase of mast cells has been found in asthma patients. However, how these cells are involved in the development of asthma are not well defined. To investigate the role of mast cells in the pathophysiological characteristics of asthma, we established asthma models in guinea pigs, which have many similarities with humans, by exposing the animals to human relevant allergens: house dust mite (HDM) and cat dander extract (CDE). The involvement of mast cells in asthma-like features was investigated either by the addition of mast cell mediator antagonists or inhibitors, or inducing mast cell death. In paper I, we repeatedly exposed guinea pigs to HDM via intranasal instillation for seven weeks and successfully recaptured the antigen induced bronchoconstriction, the production of HDM specific immunoglobulins, AHR, eosinophilic inflammation with an increase of IL-13, airway remodeling (e.g., subepithelial collagen deposition and goblet cell hyperplasia) and mast cell hyperplasia. This model can be further used to study the role of mast cells in asthma. In paper II, we exposed guinea pigs to HDM or CDE intranasally for different time. Both HDM and CDE induce airway inflammation and airway remodeling after 4 weeks’ antigen exposures. These increases maintained after 8- and 12-week exposures. Exposing to both antigens for 8 weeks and 12 weeks induced a clear expansion of mast cells which is predominated by mast cells expressing tryptase. An increase of mast cells expressing both tryptase and chymase were also observed. In paper III, we isolated guinea pig trachea for comparing the effect of different mast cell agonists (HDM and Compound 48/80 (C48/80)) on airway smooth muscle responses and mediator release. We found that histamine, prostaglandins and 5- lipoxygenase products mediated the bronchoconstriction induced by HDM and C48/80. Both agonists induced a release of histamine, prostaglandin D2 and leukotriene B4. However, distinct of lipid mediator profiles were observed. The leukotriene E4 was only elevated by HDM, whereas C48/80 induced a broader release of lipid mediators. In paper IV and V, we identified an antibiotic monensin that can induce mast cell death. To examine if monensin can be a tool for investigating the role of mast cells in asthma, we cultured guinea pig tracheal segments from HDM sensitized guinea pigs and human bronchi with different concentrations of monensin for different time. We found that monensin has robust effects on causing mast cell death and totally blocked the HDM (in guinea pig trachea) and anti-IgE (in human bronchi) induced bronchoconstriction after 2 to 72h exposure without affecting the general tissue viability at low concentration. In the in vivo investigations, we exposed the guinea pigs to HDM repeatedly with or without monensin interventions. Monensin reduced the AHR, airway inflammation and mast cell hyperplasia in the HDM induced guinea pig model. In conclusion, exposing to human relevant allergens (HDM and CDE) are suitable for modeling of allergic asthma in guinea pigs. The increase of mast cells by HDM and CDE helps to investigate the role of mast cells in asthma models. Mast cells in guinea pig airways can respond differently to antigen and non-antigen agonists. Monensin can be a robust tool to induce mast cell death. The antigen induced bronchoconstriction by HDM in guinea pig trachea and anti-IgE in human bronchi are purely mast cell mediated. Our findings emphasize that mast cells have important roles in the development of AHR and airway inflammation in the guinea pig model used in this PhD study. The findings in this thesis highlight the importance of mast cells in asthma and the models we developed can be used as important tools for defining the mechanisms behind asthma

Salmon In Pregnancy Study (SIPS): the effects of increased oily fish intake during pregnancy on maternal and cord blood fatty acid composition, cord blood immunity and atopy outcomes in infants at 6 months of age

Parallel increases in many inflammatory diseases including atopy over the last 40 years suggest that common environmental changes may be promoting inflammatory immune responses. Modern diets have become increasingly rich in n-6 polyunsaturated fatty acids (PUFAs) and relatively deficient in n-3 PUFAs. These dietary changes are believed to promote a pro-sensitisation, pro-allergic and pro-inflammatory environment. Exposure to such an environment during pregnancy and in the very early life period is considered to influence subsequent patterns of the immature and developing neonatal immune system, and this may contribute to the increase in allergic disease in early life. As allergic diseases often first manifest in infancy, prevention strategies need to be targeted early, even in utero. Epidemiologic and experimental data provide a plausible link between dietary changes and increased incidence of childhood atopic disease. Although there have been studies examining the potential benefits of giving n-3 PUFA-rich fish oil supplements during pregnancy, there are no studies examining the effects of increased consumption of oily fish in pregnancy on neonatal immune responses and subsequent clinical outcomes.The Salmon in Pregnancy Study (SIPS) is the first randomised controlled trial of oily fish intervention during pregnancy. The hypotheses being investigated in SIPS is that increased intake of salmon, a source of long chain (LC) n-3 PUFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), in pregnancy will a) increase maternal LC n-3 PUFA intake, b) increase maternal and infant blood LC n-3 PUFA status, c) modulate fetal/neonatal immune responses and d) lower the risk of infant atopy determined at 6 months of age. The primary outcome measures of SIPS were the clinical signs of atopy in the offspring.Pregnant women (n=123) at high risk of having atopic offspring, and with low habitual intake of oily fish (? 2/month) were randomised at 20 weeks of pregnancy to either consuming 2 portions/week of farmed salmon (n=62) or continuing their habitual diet (n=61) until the end of pregnancy. The woman attended a clinic at 20 (n=123), 34 (n=110) and 38 (n=91) weeks of gestation at which fasting blood was collected and a food frequency questionnaire (FFQ) was administered (at 20 and 34 weeks). At delivery umbilical cord blood was collected (n=101) for fatty acid and immunological analysis. Infants attended a clinic at 6 months of age (n=86) for assessment of allergic sensitisation by skin prick testing (SPT) using various allergen extracts and of atopic dermatitis (SCORAD index).Maternal and cord plasma and cord blood mononuclear cell (CBMC) fatty acid compositions were determined by gas chromatography. Neonatal (cord) immune cell subsets were identified by flow cytometry. Ex-vivo cytokine production by CBMC in response to stimulants (allergen, mitogen, and toll-like receptor (TLR) ligands) was determined by cytometric bead array and flow cytometry. Ex-vivo prostaglandin E2 production by CBMC was determined by enzyme-linked immunosorbent assay. Immunoglobin E concentration was measured in cord blood plasma and in 6 month infant blood plasma.Eating oily fish twice a week during pregnancy resulted in a higher maternal intake of LC n-3 PUFAs (both EPA and DHA) and in higher maternal and cord blood plasma status of LC n-3 PUFAs (both EPA and DHA). LC n-3 PUFA content of CBMC was not significantly affected. CBMC production of interleukins-2, -4, -5, and -10 and tumour necrosis factor-? was lower in the salmon group. There was no effect of salmon on the atopic outcomes assessed at 6 months

Tracking Arachis hypogaea Allergen in Pre-Packaged Foodstuff: A Nanodiamond-Based Electrochemical Biosensing Approach

The present work reports a nanodiamond-based voltammetric immunosensing platform for the analysis of a food allergen (Ara h 1) present in peanuts (Arachis hypogaea). The possibility of the usage of nanodiamonds (d = 11.2 ± 0.9 nm) on screen-printed carbon electrodes (SPCE/ND) in a single-use two-monoclonal antibody sandwich assay was studied. An enhanced electroactive area (~18%) was obtained and the biomolecule binding ability was improved when the 3D carbon-based nanomaterial was used. The antibody-antigen interaction was recognized through the combination of alkaline phosphatase with 3-indoxyl phosphate and silver ions. Linear Sweep Voltammetry (LSV) was applied for fast signal acquisition and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) support the voltammetric approach and confirm the presence of silver particles on the electrode surface. The proposed immunosensor provided a low limit of detection (0.78 ng·mL−1) and highly precise (RSD < 7.5%) and accurate results. Quantification of Ara h 1 in commercial foodstuffs (e.g., crackers, cookies, protein bars) that refer to the presence of peanuts (even traces) on the product label was successfully achieved. The obtained data were in accordance with recovery results (peanut addition, %) and the foodstuff label. Products with the preventive indication “may contain traces” revealed the presence of peanuts lower than 0.1% (m/m). The method’s results were validated by comparison with an enzyme-linked immunosorbent assay. This allows confident information about the presence of allergens (even at trace levels) that leads to profitable conditions for both industry and consumers.This research received financial support from the European Union (FEDER funds through COMPETE POCI-01-0145-FEDER-030735) and National Funds (Fundação para a Ciência e a Tecnologia (FCT)) through the project PTDC/QUI-QAN/30735/2017—TracAllerSens—Electrochemical sensors for the detection and quantification of trace amounts of allergens in food products.info:eu-repo/semantics/publishedVersio