Nonasthmatic Subjects Research Articles

The Nasal Nitric Oxide Response to External Acoustic Energy: A Pilot Study of Sampling Dynamics

Background: The paranasal sinuses serve as a reservoir of nitric oxide (NO), contributing to baseline nasal NO (nNO) levels. nNO has also been shown to increase transiently with humming, a response that may be blunted in severe rhinosinusitis. Blunting of the acoustically-induced nNO transient (“spike”) has been proposed as a screening test for osteomeatal complex (OMC) obstruction in sinusitis. Preparatory to conducting a clinical evaluation study, to eliminate variation in patient effort during this maneuver, we evaluated the use of external acoustic energy—in place of humming—to elicit nNO transients, documenting the effects of varying stimulus amplitude and gas sampling rates. Methods: Non-smoking, non-asthmatic subjects with no history of chronic sinusitis or nasal polyposis underwent nNO measurements in triplicate under: (1) control (quiet) conditions, and (2) with 128 Hz external acoustic energy. In Experiment 1, twelve subjects were exposed to two different intensities of external acoustic energy at 3 L/min sampling rate. In Experiment 2, a subset of nine subjects was sampled with and without acoustic stimulation at three different gas sampling rates (1, 2, and 3 L/min). Results: Experiment 1: Subjects, as a group, showed intensity-related increases in nNO with increasing acoustic amplitude (p < 0.01). Experiment 2: independently, both applied acoustic energy and lower nasal gas sampling rates increased measured nNO levels (p < 0.05 to p < 0.0001). Longitudinally, baseline (quiet) nNO obtained on a repeated basis in the two experiments (n = 9) was highly reproducible (R2 = 0.84; p < 0.001), and acoustically-stimulated nNO was moderately so (R2 = 0.50; p < 0.05). Conclusions: Application of external acoustic energy is a practical alternative to humming for mobilizing NO from the paranasal sinuses, and could be more objectively applied in any future validation studies involving clinical sinusitis and/or OMC obstruction.

Corticosteroid therapy and airflow obstruction influence the bronchial microbiome, which is distinct from that of bronchoalveolar lavage in asthmatic airways

The lung has a diverse microbiome that is modest in biomass. This microbiome differs in asthmatic patients compared with control subjects, but the effects of clinical characteristics on the microbial community composition and structure are not clear. We examined whether the composition and structure of the lower airway microbiome correlated with clinical characteristics of chronic persistent asthma, including airflow obstruction, use of corticosteroid medications, and presence of airway eosinophilia. DNA was extracted from endobronchial brushings and bronchoalveolar lavage fluid collected from 39 asthmatic patients and 19 control subjects, along with negative control samples. 16S rRNA V4 amplicon sequencing was used to compare the relative abundance of bacterial genera with clinical characteristics. Differential feature selection analysis revealed significant differences in microbial diversity between brush and lavage samples from asthmatic patients and control subjects. Lactobacillus, Pseudomonas, and Rickettsia species were significantly enriched in samples from asthmatic patients, whereas Prevotella, Streptococcus, and Veillonella species were enriched in brush samples from control subjects. Generalized linear models on brush samples demonstrated oral corticosteroid use as an important factor affecting the relative abundance of the taxa that were significantly enriched in asthmatic patients. In addition, bacterial α-diversity in brush samples from asthmatic patients was correlated with FEV1 and the proportion of lavage eosinophils. The diversity and composition of the bronchial airway microbiome of asthmatic patients is distinct from that of nonasthmatic control subjects and influenced by worsening airflow obstruction and corticosteroid use.

Airway epithelial dual oxidase 1 mediates allergen-induced IL-33 secretion and activation of type 2 immune responses

The IL-1 family member IL-33 plays a critical role in type 2 innate immune responses to allergens and is an important mediator of allergic asthma. The mechanisms by which allergens provoke epithelial IL-33 secretion are still poorly understood. Based on previous findings indicating involvement ofthe NADPH oxidase dual oxidase 1 (DUOX1) in epithelial wound responses, we explored the potential involvement of DUOX1 in allergen-induced IL-33 secretion and potential alterations in airways of asthmatic patients. Cultured human or murine airway epithelial cells or mice were subjected to acute challenge with Alternaria alternata or house dust mite, and secretion of IL-33 and activation of subsequent type 2 responses were determined. The role of DUOX1 was explored by using small interfering RNA approaches and DUOX1-deficient mice. Cultured nasal epithelial cells from healthy subjects or asthmatic patients were evaluated for DUOX1 expression and allergen-induced responses. Invitro or invivo allergen challenge resulted in rapid airway epithelial IL-33 secretion, which depended critically on DUOX1-mediated activation of epithelial epidermal growth factor receptor and the protease calpain-2 through a redox-dependent mechanism involving cysteine oxidation within epidermal growth factor receptor and the tyrosine kinase Src. Primary nasal epithelial cells from patients with allergic asthma were found to express increased DUOX1 and IL-33 levels and demonstrated enhanced IL-33 secretion in response to allergen challenge compared with values seen in nasal epithelial cells from nonasthmatic subjects. Our findings implicate epithelial DUOX1 as a pivotal mediator of IL-33-dependent activation of innate airway type 2 immune responses to common airborne allergens and indicate that enhanced DUOX1 expression and IL-33 secretion might present important contributing features of allergic asthma.

Small RNA profiling reveals deregulated phosphatase and tensin homolog (PTEN)/phosphoinositide 3-kinase (PI3K)/Akt pathway in bronchial smooth muscle cells from asthmatic patients

Aberrant expression of small noncoding RNAs (sncRNAs), microRNAs (miRNAs) and PIWI-interacting RNAs (piRNAs) in particular, define several pathologic processes. Asthma is characterized by airway hyperreactivity, chronic inflammation, and airway wall remodeling. Asthma-specific miRNA profiles were reported for bronchial epithelial cells, whereas sncRNA expression in asthmatic bronchial smooth muscle (BSM) cells is almost completely unexplored. We sought to determine whether the primary BSM sncRNA expression profile is altered in asthmatic patients and identify targets of differentially expressed sncRNAs. Small RNA sequencing was used for sncRNA profiling in BSM cells (from 8 asthmatic and 6 nonasthmatic subjects). sncRNA identification and differential expression analysis was performed with iMir software. Experimentally validated miRNA targets were identified by using Ingenuity Pathway Analysis, and putative piRNA targets were identified by using miRanda software. BSM cells from asthmatic patients showed abnormal expression of 32 sncRNAs (26 miRNAs, 5 piRNAs, and 1 small nucleolar RNA). Target prediction for deregulated miRNAs and piRNAs revealed experimentally validated and predicted mRNA targets expressed in the BSM cells. Thirty-eight of these mRNAs represent major targets for deregulated miRNAs and might play important roles in the pathophysiology of asthma. Interestingly, 6 of these mRNAs were previously associated with asthma, considered as novel therapeutic targets for treatment of this disease, or both. Signaling pathway analysis revealed involvement of 38 miRNA-targeted mRNAs in increased cell proliferation through phosphatase and tensin homolog and phosphoinositide 3-kinase/Akt signaling pathways. BSM cells of asthmatic patients are characterized by aberrant sncRNA expression that recapitulates multiple pathologic phenotypes of these cells.

Defective Resensitization in Human Airway Smooth Muscle Cells Evokes β-Adrenergic Receptor Dysfunction in Severe Asthma.

β2-adrenergic receptor (β2AR) agonists (β2-agonist) are the most commonly used therapy for acute relief in asthma, but chronic use of these bronchodilators paradoxically exacerbates airway hyper-responsiveness. Activation of βARs by β-agonist leads to desensitization (inactivation) by phosphorylation through G-protein coupled receptor kinases (GRKs) which mediate β-arrestin binding and βAR internalization. Resensitization occurs by dephosphorylation of the endosomal βARs which recycle back to the plasma membrane as agonist-ready receptors. To determine whether the loss in β-agonist response in asthma is due to altered βAR desensitization and/or resensitization, we used primary human airway smooth muscle cells (HASMCs) isolated from the lungs of non-asthmatic and fatal-asthmatic subjects. Asthmatic HASMCs have diminished adenylyl cyclase activity and cAMP response to β-agonist as compared to non-asthmatic HASMCs. Confocal microscopy showed significant accumulation of phosphorylated β2ARs in asthmatic HASMCs. Systematic analysis of desensitization components including GRKs and β-arrestin showed no appreciable differences between asthmatic and non-asthmatic HASMCs. However, asthmatic HASMC showed significant increase in PI3Kγ activity and was associated with reduction in PP2A activity. Since reduction in PP2A activity could alter receptor resensitization, endosomal fractions were isolated to assess the agonist ready β2ARs as a measure of resensitization. Despite significant accumulation of β2ARs in the endosomes of asthmatic HASMCs, endosomal β2ARs cannot robustly activate adenylyl cyclase. Furthermore, endosomes from asthmatic HASMCs are associated with significant increase in PI3Kγ and reduced PP2A activity that inhibits β2AR resensitization. Our study shows that resensitization, a process considered to be a homeostasis maintaining passive process is inhibited in asthmatic HASMCs contributing to β2AR dysfunction which may underlie asthma pathophysiology and loss in asthma control.

Computed Tomography Assessment of Airways Throughout Bronchial Tree Demonstrates Airway Narrowing in Severe Asthma

To analyze airway dimensions throughout the bronchial tree in severe asthmatic patients using multidetector row computed tomography (MDCT) focusing on airway narrowing. Thirty-two patients with severe asthma underwent automated (BronCare software) analysis of their right lung bronchi, with counts of airways >3 mm long arising from the main bronchi (airway count) and bronchial dimension quantification at segmental and subsegmental levels (lumen area [LA], wall area [WA], and WA%). Focal bronchial stenosis was defined as >50% narrowing of maximal LA on contiguous cross-sectional slices. Severe asthmatics were compared to 13 nonsevere asthmatic patients and nonasthmatic (pooled) subjects (Wilcoxon rank tests, then stepwise logistic regression). Finally, cluster analysis of severe asthmatic patients and stepwise logistic regression identified specific imaging subgroups. The most significant differences between severe asthmatic patients and the pooled subjects were bronchial stenosis (subsegmental and all bronchi: P < .002) and WA% (P < .0003). Stepwise logistic regression retained WA% as the only explanatory covariable (P = .002). Two identified clusters of severe asthmatic patients differed for parameters characterizing airway narrowing (airway count: P = .0002; focal bronchial stenosis: P = .009). Airway count was as discriminant as forced expiratory volume in 1 second/forced vital capacity (P = .01) to identify patients in each cluster, with both variables being correlated (r = 0.59, P = .005). Severe asthma-associated morphologic changes were characterized by focal bronchial stenoses and diffuse airway narrowing; the latter was associated with airflow obstruction. WA%, dependent on airway caliber, is the best parameter to identify severe asthmatic patients from pooled subjects.

Cyclooxygenase-2 and microRNA-155 expression are elevated in asthmatic airway smooth muscle cells.

Cyclooxygenase-2 (COX-2) expression and PGE2 secretion from human airway smooth muscle cells (hASMCs) may contribute to β2-adrenoceptor hyporesponsiveness, a clinical feature observed in some patients with asthma. hASMCs from patients with asthma exhibit elevated expression of cytokine-responsive genes, and in some instances this is attributable to an altered histone code and/or microRNA expression. We hypothesized that COX-2 expression and PGE2 secretion might be elevated in asthmatic hASMCs in response to proinflammatory signals in part due to altered histone acetylation and/or microRNA expression. hASMCs obtained from nonasthmatic and asthmatic human subjects were treated with cytomix (IL-1β, TNF-α, and IFN-γ). A greater elevation of COX-2 mRNA, COX-2 protein, and PGE2 secretion was observed in the asthmatic cells. We investigated histone H3/H4-acetylation, transcription factor binding, mRNA stability, p38 mitogen-activated protein kinase signaling, and microRNA (miR)-155 expression as potential mechanisms responsible for the differential elevation of COX-2 expression. We found that histone H3/H4-acetylation and transcription factor binding to the COX-2 promoter were similar in both groups, and histone H3/H4-acetylation did not increase after cytomix treatment. Cytomix treatment elevated NF-κB and RNA polymerase II binding to similar levels in both groups. COX-2 mRNA stability was increased in asthmatic cells. MiR-155 expression was higher in cytomix-treated asthmatic cells, and we show it enhances COX-2 expression and PGE2 secretion in asthmatic and nonasthmatic hASMCs. Thus, miR-155 expression positively correlates with COX-2 expression in the asthmatic hASMCs and may contribute to the elevated expression observed in these cells. These findings may explain, at least in part, β2-adrenoceptor hyporesponsiveness in patients with asthma.

Jug r 2–reactive CD4+ T cells have a dominant immune role in walnut allergy

BackgroundAllergic reactions to walnut can be life threatening. While IgE epitopes of walnut have been studied, CD4+ T-cell specific epitopes for walnut remain uncharacterized. Particularly, the relationship of both phenotype and frequency of walnut specific T-cells to the disease have not been examined.ObjectivesWe sought to provide a thorough phenotypic analysis for walnut reactive T-cells in allergic and non-allergic subjects. Particularly, the relationship of phenotypes and frequencies of walnut specific T-cells with the disease.MethodsCD154 up-regulation assay was used to examine CD4+ T-cell reactivity towards walnut allergens.Jug r 1, Jug r 2 and Jug r 3. Tetramer-Guided epitope mapping approach was utilized to identify HLA-restricted CD4+ T-cells epitopes in Jug r 2. Direct ex vivo staining with peptide-major histocompatibility complex class II (pMHC-II) tetramers enabled the comparison of frequency and phenotype of Jug r 2-specific CD4+ T-cells between allergic and non-allergic subjects. Jug r 2-specific T-cell-clones were also generated and mRNA transcription factor levels were assessed by RT qPCR. Intracellular cytokine staining (ICS) assays were performed for further phenotypical analyses.ResultsJug r 2 was identified as the major allergen that elicited CD4+ T-cell responses. Multiple Jug r 2 T-cell epitopes were identified. The majority of these T-cells in allergic subjects have a CCR4+ TCM (central memory) phenotype. A subset of these T-cells express CCR4+CCR6+ irrespectively of the asthmatic status of the allergic subjects. ICS confirmed these TH2, TH2/TH17 and TH17-like heterogenic profiles. Jug r 2-specific T-cell-clones from allergic subjects mainly expressed GATA3; nonetheless, a portion of T-cell clones expressed either GATA3 and RORC, or RORC, confirming the presence of TH2, TH2/TH17 and TH17 cells.ConclusionsJug r 2 specific responses dominate walnut T-cell responses in subjects with walnut allergy. Jug r 2 central memory CD4+ cells and terminal effector T-cells were detected in peripheral blood with the central memory phenotype as the most prevalent phenotype. In addition to conventional TH2-cells, TH2/TH17 and TH17 cells were also detected in non-asthmatic and asthmatic subjects with walnut allergy. Understanding this T-cell heterogeneity may render better understanding of the disease manifestation.

No evidence for altered intracellular calcium-handling in airway smooth muscle cells from human subjects with asthma.

BackgroundAsthma is characterized by airway hyper-responsiveness and variable airflow obstruction, in part as a consequence of hyper-contractile airway smooth muscle, which persists in primary cell culture. One potential mechanism for this hyper-contractility is abnormal intracellular Ca2+ handling.MethodsWe sought to compare intracellular Ca2+ handling in airway smooth muscle cells from subjects with asthma compared to non-asthmatic controls by measuring: i) bradykinin-stimulated changes in inositol 1,4,5-trisphosphate (IP3) accumulation and intracellular Ca2+ concentration, ii) sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) expression, iii) mechanisms of cytoplasmic Ca2+ clearance assessed following instantaneous flash photolytic release of Ca2+ into the cytoplasm.ResultsWe found no differences in airway smooth muscle cell basal intracellular Ca2+ concentrations, bradykinin-stimulated IP3 accumulation or intracellular Ca2+ responses. Quantification of SERCA2 mRNA or protein expression levels revealed no differences in ASM cells obtained from subjects with asthma compared to non-asthmatic controls. We did not identify differences in intracellular calcium kinetics assessed by flash photolysis and calcium uncaging independent of agonist-activation with or without SERCA inhibition. However, we did observe some correlations in subjects with asthma between lung function and the different cellular measurements of intracellular Ca2+ handling, with poorer lung function related to increased rate of recovery following flash photolytic elevation of cytoplasmic Ca2+ concentration.ConclusionsTaken together, the experimental results reported in this study do not demonstrate major fundamental differences in Ca2+ handling between airway smooth muscle cells from non-asthmatic and asthmatic subjects. Therefore, increased contraction of airway smooth muscle cells derived from asthmatic subjects cannot be fully explained by altered Ca2+ homeostasis.

Self-reported adverse reactions and IgE sensitization to common foods in adults with asthma.

BackgroundThere is very few data available on the prevalence of food hypersensitivity among adults with asthma. The aim of this study was to explore the prevalence of self-reported adverse reactions and IgE sensitization to the different foods and to determine the spectrum and the prevalence of food-related gastrointestinal symptoms in adults with and with no asthma.MethodsA cross sectional study based on interviews and questionnaire responses from 1527 subjects, aged 18–75 years of age, from Västra Götaland in Sweden, as part of the larger West Sweden Asthma Study. IgE analyses were performed in sera from all subjects.ResultsFifty three percent of adults with asthma reported adverse reactions to foods compared to 30 % of non-asthmatics. Most asthmatics reported symptoms from eating hazelnut, followed by other nuts, birch-related foods, milk, peanut and shellfish. Furthermore, adults with asthma experienced significantly more often gastrointestinal symptoms from hazelnut, apple and milk and were found to significantly more often be sensitized to the most common foods compared to the non-asthmatic subjects. The asthmatics showed a significant correlation between IgE to both hazelnut and birch and self-reported symptoms after ingestion of hazelnut and to a lesser extent to almonds.ConclusionsThe prevalence of self-reported adverse reactions and sensitization to the most common foods was much higher among the asthmatic subjects. Hazelnut was the food that asthmatics most frequently experienced adverse reactions from, and the strong correlation between IgE to hazelnut and birch indicate that the observed adverse reactions are partly due to sensitization to allergens from the PR-10 family.Electronic supplementary materialThe online version of this article (doi:10.1186/s13601-015-0067-6) contains supplementary material, which is available to authorized users.

Association of serum adiponectin with asthma and pulmonary function in the Japanese population.

Conflicting findings have been reported regarding the role of adiponectin in asthma. The aim of this study was to evaluate the association of adiponectin with pulmonary functions and asthma in the Japanese population. First, among a general population that participated in a previous study (group 1), we selected 329 subjects after excluding those with asthma, chronic obstructive pulmonary disease, and a smoking history and examined the associations of the serum total adiponectin levels with pulmonary functions. In a second cohort (group 2) consisting of 61 asthmatic patients and 175 control non-asthmatic subjects, we examined the associations between asthma and the levels of total, high (HMW), middle (MMW) and low (LMW) molecular weight adiponectin isoforms as well as the ratio of each isoform to total adiponectin level. Although the total adiponectin levels were not significantly different between the asthmatic and control subjects in group 2, the levels were significantly and positively associated with the forced expiratory volume in 1 s after adjustments for confounding factors (P < 0.05) in women in group 1. In group 2, the LMW adiponectin level was significantly higher and the MMW/total adiponectin ratio was significantly lower among the asthmatic subjects than among the control subjects after adjustments for confounding factors in both sexes (P < 0.05). The present study showed that a low total adiponectin level may lead to airway narrowing compatible with asthmatic airways in women, and higher LMW adiponectin levels and lower MMW/total adiponectin ratio are significantly associated with current asthma in both sexes.

Nonlinear Compliance Modulates Dynamic Bronchoconstriction in a Multiscale Airway Model

The role of breathing and deep inspirations (DI) in modulating airway hyperresponsiveness remains poorly understood. In particular, DIs are potent bronchodilators of constricted airways in nonasthmatic subjects but not in asthmatic subjects. Additionally, length fluctuations (mimicking DIs) have been shown to reduce mean contractile force when applied to airway smooth muscle (ASM) cells and tissue strips. However, these observations are not recapitulated on application of transmural pressure (PTM) oscillations (that mimic tidal breathing and DIs) in isolated intact airways. To shed light on this paradox, we have developed a biomechanical model of the intact airway, accounting for strain-stiffening due to collagen recruitment (a large component of the extracellular matrix (ECM)), and dynamic actomyosin-driven force generation by ASM cells. In agreement with intact airway studies, our model shows that PTM fluctuations at particular mean transmural pressures can lead to only limited bronchodilation. However, our model predicts that moving the airway to a more compliant point on the static pressure-radius relationship (which may involve reducing mean PTM), before applying pressure fluctuations, can generate greater bronchodilation. This difference arises from competition between passive strain-stiffening of ECM and force generation by ASM yielding a highly nonlinear relationship between effective airway stiffness and PTM, which is modified by the presence of contractile agonist. Effectively, the airway at its most compliant may allow for greater strain to be transmitted to subcellular contractile machinery. The model predictions lead us to hypothesize that the maximum possible bronchodilation of an airway depends on its static compliance at the PTM about which the fluctuations are applied. We suggest the design of additional experimental protocols to test this hypothesis.

The efficacy and safety of the short ragweed sublingual immunotherapy tablet MK-3641 is similar in asthmatic and nonasthmatic subjects treated for allergic rhinitis with/without conjunctivitis

(−1.27; 95% CI: −3.48, 0.93; n=56) and 22% (−1.68; 95% CI: −3.69, 0.33; n=64), respectively, versus placebo (mean TCS=7.65; n=64) over the 15-day peak season. Among subjects without asthma receiving MK-3641 6 or 12 Amb a 1-U, TCS was reduced by 21% (−1.83; 95% CI: −2.84, −0.82; n=261) and 27% (−2.34; 95% CI: −3.33, −1.35; n=247), respectively, versus placebo (mean TCS=8.73; n=269). At least one treatment-related AE was experienced by 33%, 63%, and 65% of placebo and MK-3641 6 and 12 Amb a 1-U subjects with asthma, respectively, versus 24%, 54%, and 60% of subjects without asthma. No treatment-related serious or life-threatening AEs or hypersensitivity or systemic reactions were observed. Conclusions

Rhinovirus-induced VP1-specific Antibodies are Group-specific and Associated With Severity of Respiratory Symptoms

BackgroundRhinoviruses (RVs) are a major cause of common colds and induce exacerbations of asthma and chronic inflammatory lung diseases. MethodsWe expressed and purified recombinant RV coat proteins VP1-4, non-structural proteins as well as N-terminal fragments of VP1 from four RV strains (RV14, 16, 89, C) covering the three known RV groups (RV-A, RV-B and RV-C) and measured specific IgG-subclass-, IgA- and IgM-responses by ELISA in subjects with different severities of asthma or without asthma before and after experimental infection with RV16. FindingsBefore infection subjects showed IgG1>IgA>IgM>IgG3 cross-reactivity with N-terminal fragments from the representative VP1 proteins of the three RV groups. Antibody levels were higher in the asthmatic group as compared to the non-asthmatic subjects. Six weeks after infection with RV16, IgG1 antibodies showed a group-specific increase towards the N-terminal VP1 fragment, but not towards other capsid and non-structural proteins, which was highest in subjects with severe upper and lower respiratory symptoms. InterpretationOur results demonstrate that increases of antibodies towards the VP1 N-terminus are group-specific and associated with severity of respiratory symptoms and suggest that it may be possible to develop serological tests for identifying causative RV groups.

Regulator of G-protein signaling 2 repression exacerbates airway hyper-responsiveness and remodeling in asthma.

G protein-coupled receptors (GPCRs) are important regulators of cell functions in asthma. We recently reported that regulator of G-protein signaling (RGS) 2, a selective modulator of Gq-coupled GPCRs, is a key regulator of airway hyper-responsiveness (AHR), the pathophysiologic hallmark of asthma. Because RGS2 protein levels in airway cells were significantly lower in patients with asthma compared with patients without asthma, we further investigated the potential pathological importance of RGS2 repression in asthma. The human RGS2 gene maps to chromosome 1q31. We first screened patients with asthma for RGS2 gene promoter single-nucleotide polymorphisms (SNPs) and found significant differences in the distribution of two RGS2 SNPs (A638G, rs2746071 and C395G, rs2746072) between patients with asthma and nonasthmatic subjects. These two SNPs are always associated with each other and have the same higher prevalence in patients with asthma (65%) as compared with nonasthmatic subjects (35%). Point mutations corresponding to these SNPs decrease RGS2 promoter activity by 44%. The importance of RGS2 down-regulation was then determined in an acute IL-13 mouse model of asthma. Intranasal administration of IL-13 in mice also decreased RGS2 expression in lungs by ∼50% and caused AHR. Although naive RGS2 knockout (KO) mice exhibit spontaneous AHR, acute IL-13 exposure further increased AHR in RGS2 KO mice. Loss of RGS2 also significantly enhanced IL-13-induced mouse airway remodeling, including peribronchial smooth muscle thickening and fibrosis, without effects on goblet cell hyperplasia or airway inflammation in mice. Thus, genetic variations and increased inflammatory cytokines can lead to RGS2 repression, which exacerbates AHR and airway remodeling in asthma.

Useful biomarkers for assessing the adverse health effects of PCBs in allergic children: pediatric molecular epidemiology.

The incidences of childhood allergies have been increasing in recent years in many parts of the world. The development of allergic disorders is attributed to a complex series of interactions between individuals' genetic backgrounds and their immune and psychoneurotic responses to environmental factors. Among the various possible environmental causes of childhood allergies, the early exposure of developing infants to air pollutants and the presence of persistent chemical pollutants such as pesticides have been suggested most frequently. Therefore, it is very important to obtain epidemiological evidence of direct associations between clearly defined adverse health effects and exposure to low levels of pollutants. However, there are no useful biomarkers for assessing such associations. Thus, we planned to establish reliable health-related biomarkers that could be used to investigate these relationships in children. The serum concentrations of several sub-types of polychlorinated biphenyl (PCB) congeners were found to be significantly correlated with interleukin (IL)-8 mRNA expression among asthmatic children. In addition, IL-22 mRNA expression was found to be particularly useful for detecting the effects of environmental pollutants, especially PCB congeners, in a sub-population of vulnerable children who exhibited positive immunoglobulin E (IgE) responses to milk or egg. Furthermore, we detected significant differences in IL-22 mRNA expression between the IgE-negative non-asthmatic subjects and the asthmatic children who exhibited positive IgE reactions toward egg or milk. In conclusion, IL-8 and IL-22 mRNA expressions could be useful biomarkers for detecting sub-populations of children who are particularly vulnerable to the adverse health effects of environmental pollutants, especially PCBs.

The FACT score in predicting pneumococcal antibody levels in asthmatics

Background: There is no measure currently available to identify asthmatics with potential immune incompetence. Objective: We propose use of a novel scoring system called the FACT score, which is formulated based on four parameters: (1) Family history of asthma, (2) Atopic conditions, (3) Bacterial colonization and (4) Th1 versus Th2 immune profile. Methods: This was a cross-sectional study involving 16 asthmatics and 14 non-asthmatics. The first two parameters of the FACT score were obtained via a chart review and interview. For the third parameter, nasopharyngeal swab samples were cultured. The ratio of interleukin-5 to interferon-gamma for each patient was measured by peripheral blood mononuclear cells cultured with house dust mite. Antibodies to 23 pneumococcal antigens were used for humoral immunity. Results: The FACT scores for asthmatics (mean ± SD: 5.2 ± 1.87) were higher than those for non-asthmatics (mean ± SD: 3.3 ± 1.5) (p = 0.008). Of the 16 asthmatics, 7 (44%) had 12 or more positive serotype-specific polysaccharide antibodies, whereas 12 of 14 (86%) of non-asthmatics subjects had 12 or more positive serotype-specific polysaccharide antibodies (p = 0.014). Overall, the FACT score was inversely correlated with the number of positive serotype-specific antibody levels [rho (ρ) = -0.38, p = 0.04]. The proportions of subjects with 12 or more positive serotype-specific antibodies among non-asthmatics and asthmatics below and above the median of the FACT scores were 86, 50 and 38%, respectively (p = 0.052). Conclusions: The FACT score may help us identify a subset of asthmatics with immune incompetence. Study findings need to be replicated in a larger study.

Towards whom should indoor environmental quality control be sympathetic – Asthmatics or non-asthmatics?

From two independent research studies conducted to understand effect of varying thermal and indoor air pollution exposures on non-asthmatics and asthmatics' responses and work performances, this paper attempts to answer the question: Towards whom should IEQ control be sympathetic – asthmatics or non-asthmatics? The studies were conducted in a 240 m3 field environment chamber at the National University of Singapore. Subjects, between 20 and 30 years of age, were recruited from the university community to participate in these studies. In the first study, the interventions were two room air temperatures, i.e. 21.2 ± 0.3 °C and 25.0 ± 0.2 °C at constant ventilation. This study lasted for 8 h. Data were collected for inhaled air thermal sensations and salivary α-amylase concentration before and after 8-h exposures. In the second study, subjects were exposed to limonene and ozone (of simulated outdoor origin) at realistic concentrations for 3 h. Data for subjects' work performances, perceptual responses, and salivary α-amylase concentration at initial and after 3-h exposures were reported in this paper. The main findings suggest that: (i) temperature settings should be sympathetic towards asthmatic subjects because of their higher sensitivity to temperatures at the lower spectrum of thermal comfort conditions; (ii) IAQ settings should be sympathetic towards non-asthmatic subjects because of their higher sensitivity to perceived air quality acceptability in the same temperature range. Knowledge gained from this paper has practical implications towards creation of environmentally friendly indoor environment for asthmatic and non-asthmatic building occupants.

Bronchoprotective effect of simulated deep inspirations in tracheal smooth muscle.

Deep inspirations (DIs) taken before an inhaled challenge with a spasmogen limit airway responsiveness in nonasthmatic subjects. This phenomenon is called bronchoprotection and is severely impaired in asthmatic subjects. The ability of DIs to prevent a decrease in forced expiratory volume in 1 s (FEV1) was initially attributed to inhibition of airway narrowing. However, DIs taken before methacholine challenge limit airway responsiveness only when a test of lung function requiring a DI is used (FEV1). Therefore, it has been suggested that prior DIs enhance the compliance of the airways or airway smooth muscle (ASM). This would increase the strain the airway wall undergoes during the subsequent DI, which is part of the FEV1 maneuver. To investigate this phenomenon, we used ovine tracheal smooth muscle strips that were subjected to shortening elicited by acetylcholine with or without prior strain mimicking two DIs. The compliance of the shortened strip was then measured in response to a stress mimicking one DI. Our results show that the presence of "DIs" before acetylcholine-induced shortening resulted in 11% greater relengthening in response to the third DI, compared with the prior DIs. This effect, although small, is shown to be potentially important for the reopening of closed airways. The effect of prior DIs was abolished by the adaptation of ASM to either shorter or longer lengths or to a low baseline tone. These results suggest that DIs confer bronchoprotection because they increase the compliance of ASM, which, consequently, promotes greater strain from subsequent DI and fosters the reopening of closed airways.

Impact of asthma, exposure period, and filters on human responses during exposures to ozone and its initiated chemistry products.

The impact of asthma, exposure period, and filter condition downstream of the mixing box of air-conditioning system on building occupants' perceptual response, work performance, and salivary α-amylase secretion during exposures to ozone and its initiated chemistry products is studied. The experiments were conducted in a field environmental chamber (FEC) (240 m(3)) simulating an office environment. Experiments were conducted during periods when the air-handling system operated with new or used pleated panel filters at constant recirculation (7/h) and ventilation (1/h) rates. Average ozone and secondary organic aerosols (ozone-initiated chemistry products) measured during non-asthmatic and asthmatic subjects' 3-h exposures in the FEC were in the ranges approximately 20-37 ppb and approximately 1.6-3 μg/m(3), respectively. Asthmatic subjects' perceived odor intensity and sensory (eye, nose, and throat) irritation ratings were generally lower than those of non-asthmatic subjects, possibly explaining why asthmatic subjects accept perceived air quality more than non-asthmatic subjects. However, asthmatic subjects' perceived physiological-like symptom ratings (flu, chest tightness, and headache) and concentrations of secreted salivary α-amylase were generally higher than those of non-asthmatic subjects. Asthmatic subjects had significantly lower accuracy than non-asthmatic subjects in a task that required higher concentration although they had higher work speed. Filter condition did not make any significant difference for subjects' responses.