Dose Of Methacholine Research Articles

Analysis of PC20-FEF25%–75% and ΔFVC in the methacholine bronchial provocation test

Purpose: Forced expiratory flow between 25% and 75% (FEF25%-75%) is known to sensitively reflect bronchial obstruction. Methacho line challenge test (MCT) has shown varying reduction levels of forced vital capacity (FVC) with the reduction in forced expiratory volume in 1 second (FEV1) in asthma. The aim of this study was to evaluate the clinical implication of provocative concentration causing a 20% fall in FEF25%-75% (PC20-FEF25%-75%) and the percentage fall in FVC at the PC20 dose of methacholine (△FVC). Methods: A total of 194 children who visited the hospital due to respiratory symptoms and underwent MCT were analyzed retro spectively. The patients were divided into 3 groups. Group I had both PC20-FEV1 and PC20-FEF25%-75% above 16 mg/mL; group II had a PC20-FEF25%-75% that fell below 16 mg/mL but PC20-FEV1 was 16 mg/mL or above; group III had a PC20-FEV1 and a PC20-FEF25%-75% that both fell below 16 mg/mL. Results: In group II, PC20-FEV1 was lower (P=0.026) and the rate of change in FEV1 and FEF25%-75% from baseline to 16 mg/mL of methacholine concentration was greater than in group I (both P<0.001). Levels of PC20-FEF25%-75% were higher in group II compared to group III (P<0.001). △FVC showed a correlation with PC20-FEV1 (P<0.001) only in the whole group. Conclusion: In asthmatic children, PC20-FEF25%-75% may be associated with bronchial hyperresponsiveness. △FVC was not associated with other parameters in either group. For subjects with a positive finding of PC20-FEF25%-75% and a negative finding of MCT, the pro gression to asthma can be suspected. (Allergy Asthma Respir Dis 2021;9:141-147)

In vitro tracheospasmolytic effect and acute toxicity screening of Coptosapelta flavescens Korth root ’s water extract

There are no data available regarding the bronchospasmolytic activity and toxicity of water extract of Coptosapelta flavescens Korth root (WECFR). Therefore, this study aimed to determine: a. the in vitro tracheospasmolytic effect of WECFR; b. safety of WECFR using the brine shrimp lethality test (BSLT) and immobilization of Daphnia magna larvae (IDL). In study, a guinea pig tracheal ring was contracted with methacholine and cumulative doses of WECFR solution were administered. A dose-response curve (DRC) was plotted of the percentage of the tracheal ring relaxation response. To test whether the relaxation mechanism occured through stimulation of beta2-adrenergic receptors, the tracheal ring was incubated with propranolol. Data analyzed using analysis of variance, showed that the DRC of WECFR was obtained with p &lt; 0.05 compared to the DRC of control, indicating that WECFR had a tracheospasmolytic effect. The DRC for propranolol-blocked WECFR did not shift to the right compared to the DRC of WECFR, confirming that the relaxation mechanism did not occur through the beta2-adrenergic receptors. Study b. assessed safety using BSLT and IDL. After exposing the larvae to WECFR and control for 24 and 48 h, respectively, the number of dead larvae was counted. Data analyzed using Probit program, showed that the lethal dose 50 of WECFR towards Artemia salina and Daphnia magna larvae was &gt; 1000 ppm, which means that it was not toxic. This studies demonstrate that WECFR exhibits tracheospasmolitic effect, but not through beta2-adrenergic receptors; WECFR is safe for Artemia salina and Daphnia magna larvae.

Diagnostic and Therapeutic Value of Hsa_circ_0002594 for T Helper 2-Mediated Allergic Asthma

Introduction: Circular RNAs (circRNAs) are an endogenous mircoRNA sponge that could act as potential biomarkers for the diagnosis and treatment of diseases. However, the role of circRNAs in asthma is far from clear. Objective: The aim of this study is to assess the diagnostic and therapeutic value of hsa_circ_0002594 for T helper (Th) 2-mediated allergic asthma. Methods: The expression profiles of hsa_circ_0002594 in CD4⁺ T cells were revealed by circRNA microarray. Hsa_circ_0002594 expression was confirmed via quantitative real-time PCR (qRT-PCR) in asthmatic patients and healthy subjects. Hsa_circ_0002594 levels were compared between subgroups. The clinical diagnostic abilities and therapeutic response of hsa_circ_0002594 were evaluated. The analyses utilized included a student’s t test, nonparametric tests, Spearman’s rank-order correlation, Fisher’s exact test, and the generation of receiver operating characteristic (ROC) curves. Results: Hsa_circ_0002594 was upregulated and positively correlated with fraction of exhaled nitric oxide while negatively correlated with methacholine dose producing a decrease of 20% from baseline in forced expiratory volume in the first second (PD20) in CD4⁺ T cells of asthma. Furthermore, hsa_circ_0002594 expression was higher in subgroups with a family history, skin pricking test (SPT)-positive, or Th2-high. The hsa_circ_0002594-high subgroup was more frequently associated with Th2-high biomarker profiles and positive SPT. Hsa_circ_0002594 was decreased after inhaled corticosteroids (ICS) treatment. ROC curve analyses of hsa_circ_0002594 showed high area under the curve values in the presence of ICS or not. Conclusions: Our data suggested that hsa_circ_0002594 was upregulated in CD4⁺ T cells and might have potential value in the diagnosis and treatment of Th2-mediated allergic asthma.

Altered airway mechanics in the context of obesity and asthma.

The obesity epidemic is causing a rise in asthma incidence due to the appearance of an obesity-specific late-onset nonallergic (LONA) phenotype. We investigated why only a subset of obese participants develop LONA asthma by determining how obesity, both alone and in combination with LONA asthma, affects the volume dependence of respiratory system impedance. We also determined how obesity and asthma affect impedance during and following challenge with the PC20 dose of methacholine. We found during passive exhalation that all obese participants, in contrast to lean controls and lean asthmatics, experienced similarly profound elevations in lung elastance as they approached functional residual capacity. We also found, however, that the LONA asthmatics had a greater negative dependence of airway resistance on lung volume over the middle of the volume range compared with the other groups. Methacholine challenge with the PC20 dose led to comparable changes in respiratory system impedance in the four study groups, but the doses themselves were substantially lower in both obese and lean asthmatic participants compared with obese and lean controls. Also, the obese LONA asthmatics had higher breathing frequencies and lower tidal volumes postchallenge compared with the other participants. Taken together, these results suggest that all obese individuals experience substantial lung collapse as they approach functional residual capacity, presumably due to the weight of the chest wall. It remains unclear why obese LONA asthmatics are hyperresponsive to methacholine while obese nonasthmatic individuals are not.NEW & NOTEWORTHY Why only a subset of severely obese subjects develop late-onset nonallergic (LONA) asthma remains unknown, although it is widely assumed that compression of the lungs by the chest wall is somehow involved. We show that lung compression is common to obese individuals both without asthma and with LONA asthma but that those with LONA asthma may have increased airway wall compliance and possibly also a reduced ability to recruit collapsed lung.

Calcium‐Sensing Receptor (CaSR) Modulates Hyperoxia‐Induced Airway Hyperreactivity In a Neonatal Mouse Model of Bronchopulmonary Dysplasia

Supplemental O2 is a primary mode of respiratory therapy for preterm infants. Numerous studies, however, have shown that supplemental O2 may contribute to the pathophysiology of airway hyperreactivity (AHR) associated with wheezing disorders such as asthma later in childhood. The calcium‐sensitive receptor (CaSR) is a potent modulator of smooth muscle contractility and may be an underlying feature of childhood asthma. In the present study, we investigated whether CaSR is involved in neonatal hyperoxia induced AHR in a mouse model of BPD. We hypothesize that inhibition (CaSR antagonism), downregulation of expression (siRNA), or deletion (CaSR KO mice) of CaSR will attenuate the AHR induced by hyperoxia in neonatal mice. Newborn C57BL/6 wild‐type (background) or CaSR−/− (knockout) mice were randomized on the second day of life and assigned to room air (21% O2) or hyperoxic (40% O2) groups and exposed for seven days, then recovered in room air for two additional weeks. At day P21, AHR was assessed in vitro using precision‐cut living lung slice preparations in response to increasing doses of methacholine (MCh, 0.25–8 μM). Wild‐type lung slices were pre‐incubated for 48 h in a CaSR siRNA sequence (40 nM) or scrambled RNA as a negative control. In another set of experiments, slices were pre‐incubated in a CaSR antagonist – NPS 2143 (10 nM) for 1 h. Airways were imaged and airway reactivity was expressed as percent change from baseline airway lumen area (± SEM). Neonatal hyperoxia significantly increased airway contractile responses to MCh in wild‐type mice with a mean maximal effect (Emax) of 68.4±8.7% decrease in airway lumen area compared to room air controls (47.3±5.8%, p&lt;0.001), indicating AHR. Pre‐incubation (48hrs) with siRNA targeting CaSR or pharmacologic inhibition (NPS 2143, 1hr incubation) of CaSR reversed the hyperoxia‐induced AHR and the contractile responses were normalized to control level, with hyperoxic groups Emax of 44.0±5.2% and 41.3±3.1%, respectively. AHR was not observed in CaSR knockout mice suggesting resistance to hyperoxia exposure. These data suggest that CaSR plays an important role in the long‐term effects of neonatal hyperoxia on AHR. We speculate that CaSR may be a novel therapeutic target to reverse airway hyperreactivity in former preterm infants who had received prior supplemental O2 therapy.Support or Funding InformationFunding: NIH: HL R01 138402 and NIH R01 HL 056470

Methacholine dose response curve and acceptability criteria of respiratory mechanics modeling

Aim: This study aimed to analyze the Constant Phase Model (CPM) Coefficient of Determination (COD) and an index of harmonic distortion () behavior in intravenous methacholine dose response curve. We studied the COD and behavior of Control and Lung Inflammation (OVA) groups of mice and we proposed an alternative for moments when the CPM should not be applied. Methods: 9-week female BALB/c mice were studied, 8 of the control group (23.11 ± 1.27 g) and 11 of the lung inflammation group (OVA) (21.45 ± 2.16 g). The COD values were obtained during the respiratory mechanics assessment via Forced Oscillation Technique (FOT) and the was estimated a posteriori. Both control and OVA groups were submitted to 4 doses of Methacholine (MCh) protocol. Results: A strong correlation between COD and was present at the last two doses (0.3 mg/kg: r = −0.75, p = 0.0013 and 1 mg/kg: r = −0.91; p < 0.0001) in the OVA group. Differences were found in doses of 0.3 mg/kg between control and OVA for the maximum values of Rn (Newtonian Resistance) and G (tissue viscous); and between groups at PBS and doses of 0.03, 0.1 and 0.3 mg/kg for H (Elastance). A similar behavior was observed for the analysis of Area Under the Curve with the exclusion of the 3 first measurements of each dose. However, in this scenario, the comparison with the maximum value presented a higher discriminatory capacity of the parameters associated with the parenchyma. Conclusions: During severe bronchoconstriction there is a strong negative correlation between model goodness of fit and nonlinearities levels, reinforcing that COD is a robust acceptance criterion, whether still simple and easily obtained from the ventilator. We also pointed out the area under the CPM parameters dose response curve is a useful and can be used as a complementary analysis to peak comparison following bolus injections of methacholine.

FEV1 recovery following methacholine challenge in asthma: Variability and comparison of methods

BackgroundMethacholine challenges have been used in clinical trials to assess therapeutic effects and potential adverse reactions of interventions on pulmonary function in a sensitive population, such as in subjects with asthma. Here, we evaluate the variability of the methacholine challenge recovery model, and compare the results obtained for both incremental and bolus challenge methods. MethodsThe extent, time course and variability of change in forced expiratory volume in 1 s (FEV1) following repeated methacholine challenges in subjects with mild asthma were investigated in an open-label, four-period, fixed-sequence, two-method, replicate crossover study. At Visits 1 and 2, subjects underwent an incremental challenge using doubling doses of methacholine until a ≥20% decrease in FEV1 was observed; at Visits 3 and 4, subjects underwent a bolus challenge, inhaling a single dose of methacholine calculated from the cumulative dose established during Visit 1. ResultsA total of 19 subjects were included in the study. Both the mean FEV1 area under the curve (FEV1 AUC0–tz) and mean maximum reductions in FEV1 (absolute and relative) 120 min post-challenge values were higher for the incremental challenges than the bolus challenges, with no reported difference between repetitions of the same methodology. FEV1 AUC0–tz decrease 120 min post challenge demonstrated an intra-subject coefficient of variation (CV) of 47.2% (incremental) and 78.3% (bolus), suggesting considerable between-visit variability. The mean absolute, and similarly relative, maximum reductions in FEV1 compared with post-diluent baseline values demonstrated lower intra-subject variability (incremental 21.16%, bolus 40.67%) than the FEV1 AUC0–tz-based endpoint.There was a trend towards faster recovery following the bolus challenge than with the incremental challenge. The provocative dose of methacholine inducing a ≥20% decrease in FEV1 resulted in a between-group mean difference of 27.20% in the incremental challenge periods, with a high intra-subject CV of 80.64%, demonstrating considerable variability. ConclusionMaximum reduction in FEV1 had the lowest variability. There was little difference between repetitions of the same methodology, as indicated by overlapping confidence intervals. There was a trend towards faster recovery following bolus challenge than with the incremental challenge. The results of this trial could be of value when designing future clinical trials using the methacholine challenge methodology.

In Vitro Study of Bronchial Relaxation Mechanism of Coptosapelta Flavescens Korth Root’s Methanol Extract On Receptors

Objective: To evaluate the bronchorelaxation effect of methanol extract of Coptosapelta flavescens Korth. ischolar_main (MECFR) on cholinergic, histamine receptors and beta2-adrenoceptors, in vitro. Method: The research design was experimental in which a 4-mm long guinea pig’s bronchus was kept in an isolated organ bath containing Kreb’s-Henseleit solution at 37°C, pH 7.4 and flooded with carbogen gas. The study was divided into 3 groups: in Group 1 and 2, the bronchial rings were incubated in 3 concentrations of MECFR, and then contracted with cumulative doses of methacholine and histamine, respectively; in Group 3, the bronchial ring was incubated in 3 concentrations of propranolol, contracted with a single dose of methacholine, and then the MECFR was administered in cumulative doses. Results: In both Group 1 and Group 2, the dose-response curves of all 3 doses of MECFR shifted to the right with lower E max (P&lt;0.05) as compared to the negative control. In Group 3, the dose-response curves showed MECFR has bronchorelaxation effect on bronchial rings both in the presence of propranolol andwithout, with similar E max (P&gt;0.05). Conclusion: MECFR exhibits bronchorelaxation effects by acting as non-competitive antagonist at the cholinergic and histamine1 receptors, and also by acting as beta 2 -adrenoceptor agonist.

Respiratory Duty Cycles in Individuals With and Without Airway Hyperresponsiveness

The respiratory duty cycle (Ti/Ttot) can influence bronchoprovocation test results and nebulized drug delivery. The Ti/Ttot has not yet been examined in individuals with airway hyperresponsiveness (AHR) in typical bronchoprovocation test conditions. This study investigated the mean Ti/Ttot in participants with and without AHR and whether the Ti/Ttot changes with increasing bronchoconstriction. Fifteen participants with AHR and fifteen participants without AHR completed this randomized crossover study. An ultrasonic spirometer was used for continuous measurement of the Ti/Ttot as participants inhaled room air or aerosolized solution. Each participant completed two methacholine challenges, one using a continuous-output vibrating mesh nebulizer/ultrasonic spirometer and one with the nebulizer only. Prior to each methacholine challenge, participants inhaled room air and aerosolized saline through the nebulizer/spirometer setup to record baseline Ti/Ttot data. The mean Ti/Ttot findings [95% CIs] during room air inhalation were 0.392 [0.378-0.406] and 0.447 [0.426-0.468] in participants with and without AHR, respectively (P < .001). The mean Ti/Ttot during saline inhalation were 0.389 [0.373-0.405] and 0.424 [0.398-0.450] in participants with and without AHR (P = .040). The Ti/Ttot showed a nonsignificant downward trend with progressive methacholine-induced bronchoconstriction. The mean Ti/Ttot in participants with AHR closely resembles the assumed Ti/Ttot of 0.40 recommended for standard use when calculating methacholine challenge results. Since the Ti/Ttot did not change significantly over the course of a methacholine challenge, the same Ti/Ttot can be used to calculate the dose of methacholine inhaled, regardless of the level of bronchoconstriction. ClinicalTrials.gov; No.: NCT03505489; URL: www.clinicaltrials.gov.

Exposure to lipopolysaccharide (LPS) reduces contractile response of small airways from GSTCD-/- mice.

IntroductionGenome-Wide Association Studies suggest glutathione S transferase C terminal domain (GSTCD) may play a role in development of Chronic Obstructive Pulmonary Disease. We aimed to define the potential role of GSTCD in airway inflammation and contraction using precision cut lung slice (PCLS) from wild-type (GSTCD+/+) and GSTCD knockout mice (GSTCD-/-).MethodsPCLS from age and gender matched GSTCD+/+ and GSTCD-/- mice were prepared using a microtome. Contraction was studied after applying either a single dose of Methacholine (Mch) (1 μM) or different doses of Mch (0.001 to 100 μM). Each slice was then treated with lipopolysaccharide (LPS) or vehicle (PBS) for 24 hours. PCLS contraction in the same airway was repeated before and after stimulation. Levels of TNFα production was also measured.ResultsThere were no differences in contraction of PCLS from GSTCD+/+ and GSTCD-/- mice in response to Mch (EC50 of GSTCD+/+ vs GSTCD-/- animals: 100.0±20.7 vs 107.7±24.5 nM, p = 0.855, n = 6 animals/group). However, after LPS treatment, there was a 31.6% reduction in contraction in the GSTCD-/- group (p = 0.023, n = 6 animals). There was no significant difference between PBS and LPS treatment groups in GSTCD+/+ animals. We observed a significant increase in TNFα production induced by LPS in GSTCD-/- lung slices compared to the GSTCD+/+ LPS treated slices.ConclusionGSTCD knockout mice showed an increased responsiveness to LPS (as determined by TNFα production) that was accompanied by a reduced contraction of small airways in PCLS. These data highlight an unrecognised potential function of GSTCD in mediating inflammatory signals that affect airway responses.

Regional airflow obstruction after bronchoconstriction and subsequent bronchodilation in subjects without pulmonary disease.

Some subjects with asthma have ventilation defects that are resistant to bronchodilator therapy, and it is thought that these resistant defects may be due to ongoing inflammation or chronic airway remodeling. However, it is unclear whether regional obstruction due to bronchospasm alone persists after bronchodilator therapy. To investigate this, six young, healthy subjects, in whom inflammation and remodeling were assumed to be absent, were bronchoconstricted with a PC20 [the concentration of methacholine that elicits a 20% drop in forced expiratory volume in 1 s (FEV1)] dose of methacholine and subsequently bronchodilated with a standard dose of albuterol on three separate occasions. Specific ventilation imaging, a proton MRI technique, was used to spatially map specific ventilation across 80% of each subject's right lung in each condition. The ratio between regional specific ventilation at baseline and after intervention was used to classify areas that had constricted. After albuterol rescue from methacholine bronchoconstriction, 12% (SD 9) of the lung was classified as constricted. Of the 12% of lung units that were classified as constricted after albuterol, approximately half [7% (SD 7)] had constricted after methacholine and failed to recover, whereas half [6% (SD 4)] had remained open after methacholine but became constricted after albuterol. The incomplete regional recovery was not reflected in the subjects' FEV1 measurements, which did not decrease from baseline (P = 0.97), nor was it detectable as an increase in specific ventilation heterogeneity (P = 0.78).NEW & NOTEWORTHY In normal subjects bronchoconstricted with methacholine and subsequently treated with albuterol, not all regions of the healthy lung returned to their prebronchoconstricted specific ventilation after albuterol, despite full recovery of integrative lung indexes (forced expiratory volume in 1 s and specific ventilation heterogeneity). The regions that remained bronchoconstricted following albuterol were those with the highest specific ventilation at baseline, which suggests that they may have received the highest methacholine dose.

S‐Nitrosoglutathione Reductase Inhibition Attenuates Airway Hyperreactivity in a Neonatal Hyperoxia‐Exposed Mouse Model

Premature infants exposed to supplemental oxygen are at risk for developing wheezing disorders and airway hyperreactivity (AHR). We have previously shown that the endogenous smooth muscle relaxant molecule, S‐nitrosoglutathione (GSNO), is degraded in neonatal hyperoxia by upregulated GSNO reductase (GSNOR) in the murine lung (Raffay, et al. Molecular Pharmacology 2016; 90(4):418–26). We hypothesize that inhibition or deletion of GSNOR will attenuate hyperoxia‐induced AHR in this neonatal mouse model. Newborn C57BL/6 wild‐type (background) or GSNOR−/− (knockout) mice were randomized on the first day of life and assigned to room air (21% O2) or hyperoxic (60% O2) groups for three weeks. At day P21, AHR was assessed in vitro using precision‐cut living lung slice preparations in response to increasing doses of bath‐applied methacholine (MCh, 0.25–64 μM). Wild‐type lung slices were pre‐incubated overnight with or without a GSNOR inhibitor (100 μM N6022). AHR is reported as percent change in airway lumen area from baseline (±SEM). 2–3 airways were imaged and averaged per animal per condition. Neonatal hyperoxia significantly increased (p&lt;0.001) airway contractile responses to MCh in wild‐type mice with a mean maximal effect (Emax) of 70.4 ± 2.1% compared to the room air control Emax of 44.5 ± 9.1%. GSNOR inhibition significantly reduced airway contractile responses in wild‐type hyperoxic slices to 34.1 ± 4.2% (p&lt;0.001). GSNOR−/− mice exposed to hyperoxia did not display increased airway contractile responses (Emax= 50.9 ± 5.5%). These studies show that neonatal hyperoxia‐exposed mice display in vitro AHR to methacholine and that inhibition or deletion of GSNOR attenuates hyperoxia‐induced AHR. We speculate that increased lung GSNOR expression is critical for neonatal hyperoxic bronchoconstriction. GSNO‐based therapies may serve as novel treatments for premature patients with AHR.Support or Funding InformationSupported by NIH 5K08HL133459‐02 and ATS Foundation Unrestricted Research GrantThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Sex Specific Effects of Obesity on Perivascular Adipose Tissue and Aortic Reactivity

Obesity is a societally prevalent disorder that affects men and women indiscriminately. Nationally, it has become a healthcare concern that impacts the wellness of 40% of US adults as per the US CDC. One disparaging issue implicated with the emerging obesity epidemic is damage to the cardiovascular system, and its differential effects on men and women. While cellular pathways primary to vascular tissue itself certainly play a role in obesity related vascular dysfunction; the condition of fat tissue surrounding vessels may also be implicated. A sex equipoised study of perivascular adipose tissue (PVAT) could potentially shed light onto the varying rates of cardiovascular health decline in men and women associated with obesity.17‐week‐old male and female, lean and obese Zucker rats (n=5 for all groups LZR/OZR) were used in this study. 2mm sections of thoracic aorta were dissected from the LZRs and OZRs. Aortic segments were mounted on a pin myograph system (DMT‐620m, AD Instruments) containing warm aerated physiological saline solution. PVAT conditioned media (PVATcm, 200mg/ml) was prepared using PVAT dissected from male and female LZR and OZR thoracic aortas. Vessels were pre‐constricted with phenylephrine (10−6M) and exposed to intensifying doses of methacholine (10−9M to 10−4M) resulting in a dose‐dependent curve used to assess baseline endothelial‐dependent relaxation (EDR). These methods were repeated and new measures were recorded after a 30min incubation with PVATcm that was native to the aortic segment. Subsequently, phenylephrine (10−9−4M) and sodium nitroprusside (SNP;10−9−4M) were used to assess endothelial‐independent relaxation and to measure total constriction. All data were analyzed via STATVIEW, using a one‐way ANOVA with significance p≤ 0.05.Male and female LZR had similar native aortic (without PVATcm) EDR (83% ± 1.5 vs. 90% ± 1.4 respectively). Incubating the LZR male and female aorta with their respective LZR PVATcm showed minor improvement in EDR (87% ± 1.6 and 94% ± 2.0). Male and female OZR native aortic EDR (64% ± 2.0 vs. 81% ± 1.7) was significantly lower compared to the male and female LZR native aorta. Incubating the female OZR aorta with their PVATcm did not significantly affect EDR (85% ± 4.4). In contrast, the male OZR aorta incubated with their PVATcm significantly reduced EDR (58% ± 2.1).These data indicate that the vasculature of obese animals is inherently damaged vs. lean animals. They also suggest that lean PVAT tissue may be advantageous to vascular health in both sexes. They further indicate that PVAT in obese males is involved in cardiovascular dysfunction, but PVAT in obese female animals elicit a response opposite of this. This suggests there may be biochemical factors present in the PVAT of obese females protecting them from cardiovascular dysfunction. The male/female dichotomy of EDR exemplified in this investigation requires further study to determine cellular pathways that may contribute to this protective mechanism.Support or Funding InformationWVINBRE: NIH Grant P20GM103434 WVCTSI : NIGM Grant 5U54GM104942‐03This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Furry Animal Allergen Component Sensitization and Clinical Outcomes in Adult Asthma and Rhinitis

Sensitization to allergen components has been linked to asthma in children, but studies in adults are lacking. To study the relation of sensitization to furry animal allergen components to risk of asthma, rhinitis, and markers of asthma severity in adults. From the West Sweden Asthma Study, a random population-representative sample of adults aged 16 to 75 years, 2006 participants were clinically examined; 1872 were analyzed for serum IgE level to a mix of aeroallergens. Those with an IgE level of more than 0.35 kUA/L to cat, dog, or horse allergen components were analyzed for specific cat (Felis domesticus [Fel d 1, Fel d 2, and Fel d 4]), dog (Canis familiaris [Can f 1, Can f 2, Can f 3, and Can f 5]), and horse (Equus caballus [Equ c 1]) allergen components. We defined monosensitization, double sensitization, and polysensitization (>2 components) patterns and applied cluster analysis to derive distinct sensitization clusters. Sensitization to each allergen component, lipocalins, each sensitization pattern, and each sensitization cluster (nonsensitized, Fel d 1-driven sensitized, and multisensitized clusters) was associated with substantial increased risk of asthma, rhinitis, concomitant asthma and rhinitis, and Asthma Control Test-controlled asthma. Fel d 1, Can f 1, Can f 2, Can f 3, polysensitization, and multisensitized cluster were further associated with increased fractional exhaled nitric oxide and eosinophil levels, but with lower PD20 methacoline (provocative dose of methacholine causing a 20% drop in FEV1) values. There was no association with asthma exacerbations, FEV1 predicted values, emergency visits or regular oral steroid use, and neutrophil levels. Sensitization to furry animal allergen components is an important predictor of asthma, rhinitis, and markers of asthma severity with increased blood eosinophils, fractional exhaled nitric oxide, and airway hyperreactivity.

Apport du test de provocation bronchique non spécifique dans le diagnostic d’asthme et d’inaptitude des militaires tunisiens

ObjectiveWe aimed to evaluate the value of the methacholine challenge test (MCT) in patients with asthma symptoms but without spirometric criteria and to determine the professional impact of asthma diagnosis by MCT in a Tunisian military population. Materials and methodsThis was a retrospective study conducted in the pulmonology department of the main military hospital in Tunis between November 2014 and March 2018 among soldiers with suspected asthma referred for aptitude assessment. All patients underwent spirometry followed by MCT. ResultsDuring the study period, 291 patient files were collected. The average age was 24.4 years (range: 18 to 48). All patients were male and exhibited bronchial hyperresponsiveness (BHR) with methacholine doses ranging from 100 to 1100μg (mean dose: 488μg). PD20 was between 100 and 400 in 45.4% of subjects compared with 400–800 in 30.9% and in 800–1100 in 23.7%. The degree of bronchoconstriction ranged from 20 to 55%. Mean bronchoconstriction in the smoking group was 32.7% vs. 20.3% in the non-smoking group (P=0.04). Bronchoconstriction was greater in the presence of rhinoconjunctivitis: 35.8% vs. 22.9% (P=0.02). We found no correlation between BHR, obesity and levels of IgE and eosinophilia. There was no correlation between the severity of HRB and sinonasal polyposis. All subjects were declared unfit for military service. ConclusionIn addition to clinical history, methacholine challenge testing plays a significant role in the diagnosis of asthma and medical screening for military service.

Dose omission to shorten methacholine challenge testing: clinical consequences of the use of a 10% fall in FEV1 threshold

IntroductionIn methacholine challenge testing (MCT), skipping a methacholine dose is suggested if FEV1 falls by < 5%. Using a larger threshold may further shorten test duration, but data supporting this hypothesis is lacking. We evaluated the safety and consequences of using a 10% FEV1 fall as threshold to skip the next dose of methacholine in patients undergoing MCT.MethodsWe reviewed MCTs performed in our center in 2017–2018. A ≤ 10% FEV1 fall allowed the omission of the next methacholine dose. Patients of interest were those in which a dose was skipped after a previous FEV1 fall outside the usual range (5–10%, termed “skip5–10%”). Adverse events [AE; mild: > 1 nebulized salbutamol dose (2.5 mg) to reach basal FEV1, palpitations; severe: hypoxemia and/or need for medical attention or intervention] were compared in the skip5–10% group and others. Regression analysis was used to identify predictors of AE.Results208 MCTs were analysed (135 males, age 52 ± 15 years). Skip5–10% occurred 111 times in 90 tests. Prevalence of AE was 5% and all were mild. Patients who developed AEs had lower FEV1, FVC and FEV1/FVC ratio, and higher lung volume values (all p < 0.05), but similar prevalence of skip5–10% (36 vs. 44%, p = 0.64). Overall, MCTs in which at least one skip5–10% occurred had a lower mean number of doses (3.1 ± 0.6 vs. 3.5 ± 1.3 doses, p = 0.007). Baseline residual volume was independently related to the development of AEs (OR 1.05, 95% CI 1.01–1.10, p = 0.01), but not the presence of a skip5–10%, even when the skipped dose directly led to the reaching of PC20 (OR 5.40, 95% CI 0.73–39.22, p = 0.10).ConclusionOmitting a methacholine dose based on a ≤ 10% fall in FEV1 occurs frequently and has the potential to shorten test duration. AE are rare, but patients with worse baseline lung function and gas trapping are at increased risk of mild side effects.

Fra2 Overexpression in Mice Leads to Non-allergic Asthma Development in an IL-13 Dependent Manner.

Background: Asthma is a complex chronic inflammatory disease characterised by airway inflammation, remodelling and hyperresponsiveness (AHR). Members of the AP-1 transcription factor family play important roles in the activation of the immune system and the control of cellular responses; however, their role in the development of asthma has not been well studied. We aimed to investigate the role of the lesser known AP-1 family member, Fra2 in experimental asthma.Methods: Phenotypic characterisation and gene expression profiling was performed on Fra2 (TG) overexpressing and wild-type mice. The efficacy of therapeutic interventions in regulating the Fra2 phenotype was determined.Results: Transcriptional profiling of TG mice revealed a high abundance of regulated genes associated with airway remodelling, inflammation and mucus production. A concomitant increase in peribronchial collagen deposition, smooth muscle thickening and mucus production was observed. TG mice possessed increased inflammatory infiltration in the lung, predominantly consisting of eosinophils and T-cells and elevated expression of Th2 cytokines and eotaxin. Furthermore, TG mice possessed severe AHR in response to increasing doses of methacholine. Glucocorticoid treatment led to a partial improvement of the asthma phenotype, whereas blockade of IL-13 via neutralising antibodies ameliorated AHR and mucus production, but had no effect on collagen deposition.Conclusion: We here describe a novel model for non-allergic asthma that does not require the application of exogenous allergens, which mimics several key features of the disease, such as airway inflammation, remodelling and hyperresponsiveness. Fra2 may represent a key molecule coordinating multiple aspects of asthma pathogenesis.

Prophylactic and therapeutic inhibition of allergic airway inflammation by probiotic Escherichia coli O83

Prophylactic and therapeutic inhibition of allergic airway inflammation by probiotic Escherichia coli O83

Aging attenuates adenosine triphosphate-induced, but not muscarinic and nicotinic, cutaneous vasodilation in men.

We evaluated the hypothesis that aging attenuates muscarinic, nicotinic, and ATP-related cutaneous vasodilation. In 11 young (24±4years) and 11 older males (61±8years), CVC was assessed at 3 forearm skin sites that were infused with either: (i) methacholine (muscarinic receptor agonist, 5 doses: 0.0125, 0.25, 5, 100, 2000mmol/L), (ii) nicotine (nicotinic receptor agonist, 5 doses: 1.2, 3.6, 11, 33, 100mmol/L), or (iii) ATP (purinergic receptor agonist, 5 doses: 0.03, 0.3, 3, 30, 300mmol/L). Each agonist was administered for 25minutes per dose. We showed that CVC at all doses of methacholine did not differ between groups. Similarly, no between-group differences in CVC were observed during nicotine administration at all doses administered. By contrast, while no differences in CVC were measured during the administration of ATP at low (0.03 and 0.3mmol/L) or high (300mmol/L) concentrations, CVC was reduced in the older relative to the young males at moderate concentrations of ATP (3mmol/L: 23±6 vs 40±13%max, 30mmol/L: 62±11 vs 83±8%max, both P≤.05). We show that aging attenuates ATP-induced, but not muscarinic or nicotinic, cutaneous vasodilation in men.

Immunomodulatory innate defence regulator (IDR) peptide alleviates airway inflammation and hyper-responsiveness

BackgroundExacerbation in asthma is associated with decreased expression of specific host defence peptides (HDPs) in the lungs. We examined the effects of a synthetic derivative of HDP, innate defence regulator...