Gene-environment interactions and airway disease in children

Inhaled medications and inhalation chambers for childhood asthma. Spanish network of working groups on asthma in pediatrics (REGAP)

Asthma, the most prevalent chronic disease in pediatric age, continues to pose challenges in its management and treatment. National and international guidelines emphasize the importance of therapeutic education (TE) to achieve disease control. TE involves imparting knowledge and skills to the patient and their family, enhancing medication adherence, rectifying errors in inhalation technique, and tailoring treatment based on individual patient characteristics. It is essential for TE to be progressive, gradual, and personalized, spanning all levels of care. Training healthcare professionals in TE is crucial, particularly for pediatricians, who must also be aware of the extensive variability of available meds and inhalers and their respective age-specific indications. Addressing this need, the REGAP Group extensively reviewed inhalers currently available in Spain for pediatric asthma treatment. The review encompassed different inhalation systems and inhaled drugs used for pediatric asthma treatment. This review will be updated annually, providing information on medications, devices, inhalation chambers, indications, and financiation. The REGAP Group hopes that these tables will be a valuable help for pediatricians in their daily clinical practice and serve as an effective TE tool.

Generational Patterns of Asthma Incidence among Immigrants to Canada over Two Decades. A Population-based Cohort Study

RATIONALE

Canada, an industrialized country with high endemic asthma rates, is characterized by a large immigrant population.

OBJECTIVES

We sought to provide insight into the relative contribution of environmental exposure to asthma risk by comparing asthma rates among recent immigrants relative to long-term residents of Canada.

METHODS

This was a population-based, retrospective cohort study performed using provincial health administrative data for all residents of Ontario, Canada. Residents with and without a diagnosis of asthma from fiscal years 1996-2012 were included. Individuals were categorized as being immigrants (landed in Canada after 1985) or long-term residents of Ontario by linkage with the Immigration, Refugees, and Citizenship Canada's Permanent Resident Database. We calculated the age- and sex-standardized incidence of asthma among residents of Ontario, and compared the incidence of asthma among immigrants and long-term residents using incidence rate ratios (IRRs).

RESULTS

Analysis of approximately 11.7 million records showed that 2.2 immigrants arrived in Canada during the study period, with over 50% from East and South Asia and the Pacific. We found that asthma incidence was lower among immigrants compared with long-term residents (IRR = 0.30; 95% confidence interval = 0.30-0.30; P < 0.001). However, Ontario-born children of immigrants from most world regions had significantly higher asthma incidence compared with children of long-term residents (IRR = 1.44; 95% confidence interval = 1.43-1.45; P < 0.001). The overall incidence of asthma in Ontario decreased between 1996 and 2012 (P_trend < 0.001). Immigrants contributed to only a small proportion of the asthma incidence in Ontario, and changes within this group did not significantly affect trends in the overall Ontario population asthma incidence.

CONCLUSIONS

The higher asthma incidence seen among children of immigrants, but not in their parents, suggests that being born in Canada was critical for determining asthma risk. These findings support the importance of in utero and/or early life exposures on asthma development.

Effectiveness of an educational program for children and their families on asthma control treatment adherence

Objective: Τo investigate the effect of an asthma care educational program for children and adolescents with asthma, on adherence to asthma control treatment and on clinical indices.Methods: Individuals newly diagnosed with asthma, aged 4-16 years, randomized to the intervention and control group. The participants were monitored for 6 weeks. At baseline, before the initiation of inhaled corticosteroids/long-acting beta₂-agonist (ICS/LABA), the intervention group attended the educational program; the control group received the usual care. Both groups were equipped with electronic monitoring devices for measuring adherence. Spirometry, exhaled nitric oxide fraction (FeNO), and asthma control test (ACT) score were measured in both groups in the pre and post-ICS/LABA initiation visit.Results: Seventy-eight participants were enrolled in this study (n = 39 to each group). Median percentage of adherence was 73% for the total sample, and 80% and 68% in intervention and control group, respectively (p < 0.001). In multivariate analysis, the program was positively associated with improved adherence (p < 0.001). ICS/LABA had a positive effect on spirometric indices, FeNO, and ACT score, whilst the educational program did not improved significantly the above variables.Conclusions: Establishing and increasing adherence is challenging. An asthma care educational program is associated with greater short-term adherence during a period of active monitoring.

Will every child have allergic rhinitis soon?

OBJECTIVES

Given the increasing prevalence of AR amongst children, we aimed to review the literature regarding the future of AR in this population.

METHODS

We searched the PubMed, Google and Proquest Central databases at Kırıkkale University Library. Search terms used were: "allergic rhinitis", "children", "paediatric", "allergy", "future", "risk factors", "treatment", "pharmacotherapy" and/or "allergen - specific immunotherapy". With regard to risk factors for allergic rhinitis, the terms "Environmental factors", "Improved hygiene", "Increased indoor allergen exposure", "Farms, villages, worms, and other parasites", "Environmental toxicants", "Diet", "Lifestyle changes", "Air pollution" and "Climate factors" were searched for. "Prevention of allergic diseases" and "Allergen-specific immunotherapy in the future" were also included in the search.

RESULTS

AR has a high prevalence and causes considerable morbidity, has associated comorbidity and features specific complications. The principal treatments rely on avoiding the allergens responsible, and administering drug treatment or immunotherapy, which targets specific antigens. Genetic drift does not explain the rising prevalence of allergic disorders, but multifactorial environmental factors are likely culprits. Amongst such environmental factors to consider are the rise in caesarean births, decreases in breast feeding, dietary changes resulting in less fresh produce being consumed, the eradication of intestinal worm infestations, alterations in the way homes are aired and heated, children taking less exercise and being outdoors for shorter periods, whilst also having more contact with pollution.

CONCLUSION

Barring substantial lifestyle alterations, more and more children are likely to develop AR. It may prove feasible to stop allergy developing in the first place through manipulation of the microbiome, but the exact format such a modification should involve remains to be discovered. Molecular allergological techniques do offer the prospect of more precisely targeted immunotherapy, the sole disease modifier at present. However, at present the complexity and cost of such interventions prevents their widespread use and research in this area is still needed. The majority of children with AR are going to be managed using nasal saline sprays, since they are the most straightforward and least risky alternative for first line treatment.

Transgenerational and intergenerational epigenetic inheritance in allergic diseases

It has become clear that early life (including in utero exposures) is a key window of vulnerability during which environmental exposures can alter developmental trajectories and initiate allergic disease development. However, recent evidence suggests that there might be additional windows of vulnerability to environmental exposures in the parental generation before conception or even in previous generations. There is evidence suggesting that information of prior exposures can be transferred across generations, and experimental animal models suggest that such transmission can be conveyed through epigenetic mechanisms. Although the molecular mechanisms of intergenerational and transgenerationational epigenetic transmission have yet to be determined, the realization that environment before conception can alter the risks of allergic diseases has profound implications for the development of public health interventions to prevent disease. Future research in both experimental models and in multigenerational human cohorts is needed to better understand the role of intergenerational and transgenerational effects in patients with asthma and allergic disease. This will provide the knowledge basis for a new approach to efficient intervention strategies aimed at reducing the major public health challenge of these conditions.

e-Monitoring of Asthma Therapy to Improve Compliance in children (e-MATIC): a randomised controlled trial

Real-time medication monitoring (RTMM) is a promising tool for improving adherence to inhaled corticosteroids (ICS), but has not been sufficiently tested in children with asthma. We aimed to study the effects of RTMM with short message service (SMS) reminders on adherence to ICS, asthma control, asthma-specific quality of life and asthma exacerbation rate; and to study the associated cost-effectiveness.In a multicentre, randomised controlled trial, children (aged 4-11 years) using ICS were recruited from five outpatient clinics and were given an RTMM device for 12 months. The intervention group also received tailored SMS reminders, sent only when a dose was at risk of omission. Outcome measures were adherence to ICS (RTMM data), asthma control (childhood asthma control test questionnaire), quality of life (paediatric asthma quality of life questionnaire) and asthma exacerbations. Costs were calculated from a healthcare and societal perspective.We included 209 children. Mean adherence was higher in the intervention group: 69.3% versus 57.3% (difference 12.0%, 95% CI 6.7%-17.7%). No differences were found for asthma control, quality of life or asthma exacerbations. Costs were higher in the intervention group, but this difference was not statistically significant.RTMM with tailored SMS reminders improved adherence to ICS, but not asthma control, quality of life or exacerbations in children using ICS for asthma.

Mitochondrial Redox Dysfunction and Environmental Exposures

SIGNIFICANCE

Mitochondria are structurally and biochemically diverse, even within a single type of cell. Protein complexes localized to the inner mitochondrial membrane synthesize ATP by coupling electron transport and oxidative phosphorylation. The organelles produce reactive oxygen species (ROS) from mitochondrial oxygen and ROS can, in turn, alter the function and expression of proteins used for aerobic respiration by post-translational and transcriptional regulation.

RECENT ADVANCES

New interest is emerging not only into the roles of mitochondria in disease development and progression but also as a target for environmental toxicants.

CRITICAL ISSUES

Dysregulation of respiration has been linked to cell death and is a major contributor to acute neuronal trauma, peripheral diseases, as well as chronic neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease.

FUTURE DIRECTIONS

Here, we discuss the mechanisms underlying the sensitivity of the mitochondrial respiratory complexes to redox modulation, as well as examine the effects of environmental contaminants that have well-characterized mitochondrial toxicity. The contaminants discussed in this review are some of the most prevalent and potent environmental contaminants that have been linked to neurological dysfunction, altered cellular respiration, and oxidation.

Neonatal hyperbilirubinemia and childhood allergic diseases: a systematic review

Studies have found a link between neonatal hyperbilirubinemia (NNH) and/or neonatal phototherapy (NPT) and childhood allergic diseases. The present systematic review was conducted to provide updated evidence and to provide direction regarding future research. A systematic search of the published literature was carried out. Observational studies including children up to 12 yr of age were included. Data extraction was carried out using a standardized data extraction form that was designed and pilot tested a priori. The analysis was carried out with the statistical software RevMan (version 5.2) [Protocol is registered at

PROSPERO

CRD42014009943]. Of 79 citations retrieved, a total of 7 good quality studies (n = 101,499) were included in the final analysis. There was a significant increase in the odds of asthma and allergic rhinitis (AR) after NNH [asthma, OR 4.26 (95% CI 4.04-4.5); AR, OR 5.37 (95% CI 4.16-6.92)] and after NPT [asthma, OR 3.81 (95% CI 3.53-4.11); AR, OR 3.04(95% CI 2.13-4.32)]. A similar increase in the trend was noted for late onset of asthma after NNH [OR 4.1 (95% CI 2.82-5.94)], and hospitalization due to asthma after NPT [OR 3.56 (95% CI 2.93-4.33)]. The GRADE evidence generated was of 'low quality'. The current evidence finds a significant increase in the odds of childhood allergic diseases after NNH and/or NPT. As observational studies were included, the evidence generated was of 'low quality'. Future studies should try to elucidate the pathophysiologic link between NNH and/or NPT and childhood allergic diseases.

Gene-environment interactions in asthma and allergic diseases: challenges and perspectives

The concept of gene-environment (GxE) interactions has dramatically evolved in the last century and has now become a central theme in studies that assess the causes of human disease. Despite the numerous efforts to discover genes associated in asthma and allergy through various approaches, including the recent genome-wide association studies, investigation of GxE interactions has been mainly limited to candidate genes, candidate environmental exposures, or both. This review discusses the various strategies from hypothesis-driven strategies to the full agnostic search of GxE interactions with an illustration from recently published articles. Challenges raised by each piece of the puzzle (ie, phenotype, environment, gene, and analysis of GxE interaction) are put forward, and tentative solutions are proposed. New perspectives to integrate various types of data generated by new sequencing technologies and to progress toward a systems biology approach of disease are outlined. The future of a molecular network-based approach of disease to which GxE interactions are related requires space for innovative and multidisciplinary research. Assembling the various parts of a puzzle in a complex system could well occur in a way that might not necessarily follow the rules of logic.

CT based computerized identification and analysis of human airways: a review

As one of the most prevalent chronic disorders, airway disease is a major cause of morbidity and mortality worldwide. In order to understand its underlying mechanisms and to enable assessment of therapeutic efficacy of a variety of possible interventions, noninvasive investigation of the airways in a large number of subjects is of great research interest. Due to its high resolution in temporal and spatial domains, computed tomography (CT) has been widely used in clinical practices for studying the normal and abnormal manifestations of lung diseases, albeit there is a need to clearly demonstrate the benefits in light of the cost and radiation dose associated with CT examinations performed for the purpose of airway analysis. Whereas a single CT examination consists of a large number of images, manually identifying airway morphological characteristics and computing features to enable thorough investigations of airway and other lung diseases is very time-consuming and susceptible to errors. Hence, automated and semiautomated computerized analysis of human airways is becoming an important research area in medical imaging. A number of computerized techniques have been developed to date for the analysis of lung airways. In this review, we present a summary of the primary methods developed for computerized analysis of human airways, including airway segmentation, airway labeling, and airway morphometry, as well as a number of computer-aided clinical applications, such as virtual bronchoscopy. Both successes and underlying limitations of these approaches are discussed, while highlighting areas that may require additional work.

The Peru Urban versus Rural Asthma (PURA) Study: methods and baseline quality control data from a cross-sectional investigation into the prevalence, severity, genetics, immunology and environmental factors affecting asthma in adolescence in Peru

OBJECTIVES

According to a large-scale international survey, Peru has one of the highest prevalences of asthma worldwide; however, data from this survey were limited to participants from urban Lima. The authors sought to characterise the epidemiology of asthma in Peru in two regions with disparate degrees of urbanisation. In this manuscript, the authors summarise the study design and implementation.

DESIGN

A cross-sectional study.

PARTICIPANTS

Using census data of 13-15-year-old adolescents from two communities in Peru, the authors invited a random sample of participants in Lima (n=725) and all adolescents in Tumbes (n=716) to participate in our study.

PRIMARY AND SECONDARY OUTCOME MEASURES

The authors asked participants to complete a questionnaire on asthma symptoms, environmental exposures and socio-demographics and to undergo spirometry before and after bronchodilator, skin allergy testing and exhaled nitric oxide testing. The authors obtained blood samples for haematocrit, total IgE levels, vitamin D levels and DNA in all participants and measured indoor particulate matter concentrations for 48 h in a random subset of 70-100 households at each site.

RESULTS

Of 1851 eligible participants, 1441 (78%) were enrolled and 1159 (80% of enrolled) completed all physical tests. 1283 (89%) performed spirometry according to standard guidelines, of which 86% of prebronchodilator tests and 92% of postbronchodilator tests were acceptable and reproducible. 92% of allergy skin tests had an adequate negative control. The authors collected blood from 1146 participants (79%) and saliva samples from 148 participants (9%). Overall amounts of DNA obtained from blood or saliva were 25.8 μg, with a 260/280 ratio of 1.86.

CONCLUSIONS

This study will contribute to the characterisation of a variety of risk factors for asthma, including urbanisation, total IgE levels, vitamin D levels and candidate genes, in a resource-poor setting. The authors present data to support high quality of survey, allergic, spirometric and genetic data collected in our study.

T(H)17 cells in asthma and inflammation

BACKGROUND

The chronic airway disease asthma causes significant burden to patients as well as the healthcare system with limited options for prevention or cure. Inadequate treatment strategies are most likely due to the complex heterogeneous nature of asthma. Furthermore, the severe asthma phenotype is characterized by the lack of a response to standard medication, namely, corticosteroids.

SCOPE OF REVIEW

In the last several years it has been shown that the eosinophilic/atopic phenotype of asthma driven by T(H)2 mechanisms is not the only immunologic pathway contributing to disease. In fact, there has been evidence revealing that severe asthmatics in particular have neutrophilic inflammation, and this is associated with corticosteroid resistance. T(H)17 cells, a recently discovered lineage of T helper cells, play an important role in lung host defense against multiple pathogens via production of the cytokine IL-17. IL-17 promotes neutrophil production and chemotaxis via multiple factors.

MAJOR CONCLUSIONS

Mouse and human studies provide robust evidence that T(H)17 cells and IL-17 play a role in severe asthma and may contribute to corticosteroid resistance.

GENERAL SIGNIFICANCE

As we learn more about T(H)17 cells in severe asthma, the goal is to potentially target this pathway for treatment in the hope of significantly improving the quality of life for those children and adults affected with this disease. This article is part of a Special Issue entitled: Biochemistry of Asthma.

Who is affected more by air pollution-sick or healthy? Some evidence from a health survey of schoolchildren living in the vicinity of a coal-fired power plant in Northern Israel

OBJECTIVE

To evaluate the effects of exposure to air pollution by NO(x) and SO(2) on the development of pulmonary function of children, characterized by different health status.

METHODS

A cohort of 1181 schoolchildren from the 2nd to 5th grades, residing near a major coal-fired power plant in the Hadera district of Israel, were subdivided into three health status groups, according to the diagnosis given by a physician at the beginning of the study period in 1996: (a) healthy children; (b) children experiencing chest symptoms, and (c) children with asthma or spastic bronchitis. Pulmonary Function Tests (PFTs) were performed twice (in 1996 and 1999) and analyzed in conjunction with air pollution estimates at the children's places of residence and several potential confounders-height, age, gender, parental education, passive smoking, housing density, length of residence in the study area and proximity to the main road.

RESULTS

A significant negative association was found between changes in PFT results and individual exposure estimates to air pollution, controlled for socio-demographic characteristics of children and their living conditions. A sensitivity analysis revealed a decrease in the Forced Expiratory Volume during the First Second (FEV(1)) of about 19.6% for children with chest symptoms, 11.8% for healthy children, and approximately 7.9% for children diagnosed with asthma. Results of a sensitivity test for the Forced Vital Capacity (FVC) were found to be similar.

CONCLUSION

Exposure to air pollution appeared to have had the greatest effect on children with chest symptoms. This phenomenon may be explained by the fact that this untreated symptomatic group might experience the most severe insult on their respiratory system as a result of exposure to ambient air pollution, which is reflected by a considerable reduction in their FEV(1) and FVC. Since asthmatic children have lower baseline and slower growth rates, their PFT change may be affected less by exposure to air pollution, reflecting a well known relationship between pulmonary function change and height growth, according to which age-specific height is very similar for preadolescent children, but shifts upward with age during the growth spurt.

Influences on adherence to pediatric asthma treatment: a review of correlates and predictors

Nonadherence to treatment is an important influence on the health outcomes of children and adolescents with pediatric asthma, which is the most prevalent childhood chronic illness. Because the factors that influence treatment adherence for pediatric asthma are not well understood, a comprehensive review of relevant research is needed. To address this need, research concerning the correlates and predictors of adherence to inhaled corticosteroid treatment for pediatric asthma was reviewed. Significant predictors and correlates of treatment adherence identified in this review were consistent with a conceptual model that included family demographic characteristics and functioning, parent and child characteristics, health care system and provider characteristics, and child health outcomes. Family functioning and parental beliefs about asthma and medication treatment demonstrated consistent relationships with treatment adherence. Future research should test multivariate models of influences on treatment adherence in pediatric asthma in prospective studies using reliable and valid measures of predictors and outcomes. Intervention studies are also needed that target potentially modifiable, empirically supported influences to enhance treatment adherence. The clinical management of pediatric asthma would be enhanced by routine assessment of barriers to treatment adherence and anticipatory interventions that address them to prevent nonadherence.

State of childhood asthma and future directions conference: overview and commentary

The Merck Childhood Asthma Network, Inc conference titled "State of Childhood Asthma and Future Directions: Strategies for Implementing Best Practices" was held December 13 to 14, 2006. Here we summarize the presentations and recommendations for systems approaches from that conference and discuss current asthma care.