Bronchial Hyperresponsiveness to Methacholine and AMP in Children With Atopic Asthma

Guideline Implementation for Improved Asthma Management and Treatment Adherence in Children in Jordan

Asthma imposes a significant social burden on children, their families, and society at large. As a chronic health condition, effective management could greatly benefit from consistent adherence to guidelines. Despite this, minimal effort has been exerted to examine the impact of asthma management guidelines and adherence to treatment on children with asthma and the mothers caring for them. This study was designed to evaluate the influence of asthma management guidelines on the knowledge and treatment adherence among children with asthma and their mothers. A quasi-experimental design was utilized, and the study was conducted at two large hospitals in Jordan: Princess Rahma Hospital and King Hussein Medical Center. A purposive sample of children aged 6-12 years (n = 100) who were accompanied by their mothers (n = 100) were recruited for this study. Data were collected using a structured questionnaire and an observation checklist before and after the implementation of guidelines. Statistical analyses were performed using SPSS. The results revealed a statistically significant improvement in knowledge related to asthma among children and their mothers (p < 0.001). Additionally, a statistically significant difference was observed in the children's adherence to their treatment regimen before and after the implementation of asthma management guidelines (p < 0.001). Moreover, the improvements in knowledge and practice related to asthma were sustained in the follow-up assessments. In conclusion, the guidelines had a beneficial effect on the children's adherence to their treatment regimen both before and after their implementation. Thus, asthma patients should adhere to conventional guidelines at various health services to manage their condition effectively.

Small-Airway Dysfunction is Involved in the Pathogenesis of Asthma: Evidence from Two Mouse Models

Background

There has been growing evidence of small-airway dysfunction in patients with asthma. Few studies have evaluated the mechanism of small-airway dysfunction in mouse models of asthma.

Purpose

We explored the correlation between small-airway spirometric variables and large-airway function or inflammation in different endotypes of asthma.

Methods

Ovalbumin (OVA) sensitization/challenge was used to produce a type 2 (T2)-high asthma model, and OVA combined with ozone exposure (OVA + ozone) was used for the T2-low asthma model with increased neutrophils. Spirometry, airway responsiveness, cytokine levels in bronchoalveolar lavage fluid (BALF), and pathological analyses of lung slices stained with hematoxylin-eosin, periodic acid–Schiff, and Masson’s trichrome stain were all determined. Muc5ac expression in lung tissue was evaluated by the reverse transcription-polymerase chain reaction (RT-PCR), and alpha-smooth muscle actin was measured by immunohistochemistry.

Results

Inflammatory cells infiltrated the lung tissue and inflammatory cytokines were increased in the BALF of both the OVA and OVA + ozone groups, compared with the control group. Peribronchial hypersecretion and collagen deposition were evident in the models. The OVA + ozone group showed greater neutrophilic infiltration and peribronchial smooth muscle proliferation than the OVA group. Large-airway obstruction, small-airway dysfunction, and airway hyperresponsiveness were confirmed in both models. Small-airway functional variables, such as MMEF (mean midexpiratory flow, average flow from 25 to 75% forced vital capacity [FVC]) and FEF50 (forced expiratory flow at 50% of FVC), were positively correlated with large-airway function and had a stronger negative correlation with airway inflammation, mucus secretion, and responsiveness than large-airway function.

Conclusion

Small-airway dysfunction was evident in the two endotypes of asthma and was correlated with severe airway inflammation, mucus hypersecretion, and airway hyperresponsiveness. The small airways may be an important target in asthma treatment, and further research in the role of small-airway variables in the pathogenesis of asthma is warranted.

Factors Associated with Positive Adenosine Challenge Test in Young Children with Suspected Asthma

Background: To investigate the predictive factors associated with positive adenosine monophosphate challenge using the auscultation method (AMP-PCW) test results. Methods: This is a prospective study of young children with suspected asthma who underwent AMP-PCW test. Patients with a positive AMP-PCW test were compared with those with a negative AMP-PCW. A multivariate logistic regression model was performed to identify the independent determinants of positive AMP-PCW. Results: A total of 159 patients completed the AMP-PCW test. The median age was 53 months. In total, 54.0% of patients had a positive AMP-PCW. The prevalence of atopic dermatitis and family history of asthma and allergy were significantly higher among the positive AMP-PCW group (P = 0.04, P = 0.02, and P = 0.007, respectively), as were the prevalences of elevated immunoglobulin E (IgE), peripheral blood eosinophils percentage (P = 0.003, P < 0.001, respectively), and number of emergency department (ED) visits/hospitalizations before AMP-PCW test (P = 0.006). A significant inverse correlation exists between peripheral blood eosinophils percentage and serum IgE levels with the AMP end-point concentrations (r = -0.302, P = 0.001, and r = -0.312, P = 0.001, respectively). In multivariate logistic regression model, peripheral blood eosinophils percentage, IgE levels, and the number of ED visits/hospitalizations before the AMP-PCW test were found as independent predictors for positive AMP-PCW test result. Conclusions: Our results suggest that bronchial responsiveness to AMP-PCW is related to proxy markers of airway inflammation (elevated eosinophils and IgE levels) and clinical exacerbation of asthma before the test. This may support the role of AMP-PCW in detecting inflammatory changes and monitoring their trend among young children with suspected asthma.

Prenatal particulate matter affects new asthma via airway hyperresponsiveness in schoolchildren

BACKGROUND

The most relevant time of PM₁₀ exposure to affect airway hyperresponsiveness (AHR) and new development of asthma in school-aged children is unclear. The aims of this study were to investigate the most critical time of PM₁₀ exposure to affect AHR and new diagnosis of asthma from AHR in school-aged children.

METHODS

Elementary schoolchildren (n = 3570) have been enrolled in a nationwide prospective 4-year follow-up survey in Korea from 2005 to 2006. Individual annual PM₁₀ exposure was estimated by using an ordinary kriging method from the prenatal period to 7 years of age. AHR at 7 years was defined by a methacholine PC₂₀ ≤8 mg/mL.

RESULTS

PM₁₀ exposure during pregnancy and at 1 year of age showed significant effects on AHR (aOR: 1.694, 95% CI: 1.298-2.209; and aOR: 1.750, 95% CI: 1.343-2.282, respectively). PM₁₀ exposure during pregnancy was associated with the risk of a new diagnosis of asthma (aOR: 2.056, 95% CI: 1.240-3.409), with the highest risk in children with AHR at age 7 (aOR: 6.080, 95% CI: 2.150-17.195). PM₁₀ exposure in the second trimester was associated with the highest risk of a new diagnosis of asthma in children with AHR at age 7 (aOR: 4.136, 95% CI: 1.657-10.326).

CONCLUSIONS

Prenatal PM₁₀ exposure in the second trimester is associated with an increased risk of a new diagnosis of asthma in school-aged children with AHR at 7 years. This study suggests that PM₁₀ exposure during a specific trimester in utero may affect the onset of childhood asthma via AHR.

Prevalence of airway hyperresponsiveness and its seasonal variation in children with asthma

BACKGROUND

Airway hyperresponsiveness (AHR) is a key feature of asthma and can be detected using various bronchoprovocation tests. In pediatric populations, the percentage of a positive methacholine challenge test (MCCTs) in children with asthma varies among studies, and some have reported seasonal variability. However, these studies have mostly been conducted in temperate regions. This study evaluated the prevalence of AHR to methacholine and its seasonal variation in asthmatic children in Taiwan, a subtropical country.

METHODS

A total of 276 children with asthma and their MCCT results were retrospectively reviewed. All were diagnosed with asthma and received asthma controllers regularly. They were assigned to four season groups depending in which season MCCTs were administered, with seasons categorized by the Central Weather Bureau of Taiwan. Subgroup analyses, including for sex, age, and atopy level, were compared for seasonal difference.

RESULTS

The prevalence of methacholine hyperresponsiveness was 70.7% (n = 195), and the children who were younger and had higher total serum IgE were more sensitive to methacholine (p = 0.019 and p < 0.005, respectively). No significant difference in AHR prevalence among seasons was observed (p = 0.480). The percentage of borderline, mild, and moderate severity of MCCT results was almost equally distributed among the seasons. In subgroup analysis, the children with a higher IgE level (≥75th percentile of all data) had a higher proportion of positive MCCTs in summer (88.6%, p = 0.016).

CONCLUSION

In total, 70% of the children with asthma in Taiwan had AHR to methacholine, which varied among seasons. Children with a higher total serum IgE level may be more seasonally dependent, particularly in summer.

Single nucleotide polymorphisms in asthma candidate genes TBXA2R, ADAM33 FCER1B and ORMDL3 in Pakistani asthmatics a case control study

BACKGROUND

Genetic variations in different loci and genes are important in asthma pathogenesis. There is much importance of various immunological pathways in the IgE secretion regulation. Alterations in any main part of these pathways can increase the risk of asthma development. Polymorphisms in these genetic markers can effect certain pathways which predict the asthma susceptibility. In the present study, SNPs directly or indirectly affecting the immunological process pathways are selected.

METHODS

This study was conducted to determine association of 16 SNPs in 10 candidate genes with asthma in Pakistani population in 333 asthmatic cases and 220 healthy controls. Genotyping was performed using the Sequenom Mass ARRAY iPLEX platform (14 SNPs) and TaqMan assay (2 SNPs).

RESULTS

The minor allele at two of the SNPs showed association with protection from asthma, rs1131882 in TBXA2R gene (OR 0.73, 95% CI 0.52-1.01, P = 0.05) and rs2280091 in the ADAM33 gene (OR 0.69, 95% CI 0.50-0.97, P = 0.03). For FCER1B gene, rs2583476 the asthmatic male gender had higher TT genotype counts as compared to controls (OR = 1.86, 95% CI = 1.09-3.17, p = 0.01). In rs11650680 of ORMDL3 gene the CT genotype is more prevalent in female asthma cases in comparison with female controls (OR = 1.99, 95% CI = 1.02-3.89, p = 0.03).

CONCLUSIONS

This data suggests that variations at TBXA2R and ADAM33 genes are found to be associated with asthma susceptibility in Pakistan. FCER1B gene is associated with male and ORMDL3 in female asthmatics. These genetic markers can be important source of asthma risk in Pakistani population.

The Lung Function Impairment in Non-Atopic Patients With Chronic Rhinosinusitis and Its Correlation Analysis

Objectives

Chronic rhinosinusitis (CRS) is common disease in otorhinolaryngology and will lead to lower airway abnormality. However, the only lung function in CRS patients and associated factors have not been much studied.

Methods

One hundred patients with CRS with nasal polyps (CRSwNP group), 40 patients with CRS without nasal polyps (CRSsNP group), and 100 patients without CRS were enrolled. The difference in lung function was compared. Meanwhile, CRSwNP and CRSsNP group were required to undergo a bronchial provocation or dilation test. Additionally, subjective and objective outcomes were measured by the visual analogue scale (VAS), 20-item Sino-Nasal Outcome Test (SNOT-20), Lund-Mackay score, Lund-Kennedy endoscopic score. The correlation and regression methods were used to analyze the relationship between their lung function and the above parameters.

Results

The forced expiratory volume in 1 second (FEV₁) and forced expiratory flow between 25% and 75% of forced vital capacity (FEF_25-75) of CRSwNP group were significantly lower than other groups (P<0.05). On peak expiratory flow, there was no difference between three groups. In CRSwNP group, FEV₁ was negatively correlated with peripheral blood eosinophil count (PBEC) and duration of disease (r=–0.348, P=0.013 and r=–0.344, P=0.014, respectively), FEF_25-75 negatively with VAS, SNOT-20 (r=–0.490, P=0.028 and r=–0.478, P=0.033, respectively) in CRSsNP group. The incidence of positive bronchial provocation and dilation test was lower in CRSwNP group (10% and 0%, respectively), with both 0% in CRSsNP group. The multiple linear regression analysis indicated that change ratio of FEV₁ before and after bronchial provocation or dilation test were correlated with PBEC in CRSwNP group (β=0.403, P=0.006).

Conclusion

CRS leading to impaired maximum ventilation and small airway is associated with the existence of nasal polyp. Lung function impairments can be reflected by PBEC, duration, VAS, and SNOT-20. In CRSwNP patients, PBEC is independent predictor of FEV₁ change ratio.

Airway hyper-responsiveness to mannitol provides a good evaluation of atopy in childhood asthma

AIM

The relationship between airway hyper-responsiveness (AHR) and atopy has been previously investigated, but there are still some issues to be clarified. The aim of this study was to assess the link between AHR and mannitol and atopy in asthmatic children.

METHODS

We evaluated 44 children with asthma, aged 6-16 years of age, using skin prick tests (SPTs), serum total and specific immunoglobulin E (IgE) levels and the mannitol challenge test (MCT).

RESULTS

We found a good correlation between AHR to mannitol and specific IgE against Dermatophagoides pteronissinus (r = -0.66, p < 0.001) and a weak correlation with specific IgE against dog dander (r = -0.33, p = 0.01) and Aspergillus fumigatus (r = -0.23, p = 0.02). Furthermore, we found a weak correlation between AHR to mannitol and serum total IgE (r = -0.30; p = 0.03), the sum of specific IgE to aeroallergens (r = -0.37, p = 0.01) and the number of positive SPTs (r = -0.31, p = 0.02).

CONCLUSION

Measuring AHR with MCT might provide an accurate evaluation of the degree of atopy in children. The patients with a higher degree of atopy were significantly more reactive to mannitol. In clinical practice, these results indicate that children with asthma who are more atopic may require more intensive treatment strategies to reduce AHR.

Loss of regulator of G protein signaling 5 promotes airway hyperresponsiveness in the absence of allergic inflammation

BACKGROUND

Although eosinophilic inflammation typifies allergic asthma, it is not a prerequisite for airway hyperresponsiveness (AHR), suggesting that underlying abnormalities in structural cells, such as airway smooth muscle (ASM), contribute to the asthmatic diathesis. Dysregulation of procontractile G protein-coupled receptor (GPCR) signaling in ASM could mediate enhanced contractility.

OBJECTIVE

We explored the role of a regulator of procontractile GPCR signaling, regulator of G protein signaling 5 (RGS5), in unprovoked and allergen-induced AHR.

METHODS

We evaluated GPCR-evoked Ca(2+) signaling, precision-cut lung slice (PCLS) contraction, and lung inflammation in naive and Aspergillus fumigatus-challenged wild-type and Rgs5(-/-) mice. We analyzed lung resistance and dynamic compliance in live anesthetized mice using invasive plethysmography.

RESULTS

Loss of RGS5 promoted constitutive AHR because of enhanced GPCR-induced Ca(2+) mobilization in ASM. PCLSs from naive Rgs5(-/-) mice contracted maximally at baseline independently of allergen challenge. RGS5 deficiency had little effect on the parameters of allergic inflammation, including cell counts in bronchoalveolar lavage fluid, mucin production, ASM mass, and subepithelial collagen deposition. Unexpectedly, induced IL-13 and IL-33 levels were much lower in challenged lungs from Rgs5(-/-) mice relative to those seen in wild-type mice.

CONCLUSION

Loss of RGS5 confers spontaneous AHR in mice in the absence of allergic inflammation. Because it is selectively expressed in ASM within the lung and does not promote inflammation, RGS5 might be a therapeutic target for asthma.