Genetics of asthma: an introduction for the clinician

Genetic Prediction Modeling in Large Cohort Studies via Boosting Targeted Loss Functions

Polygenic risk scores (PRS) aim to predict a trait from genetic information, relying on common genetic variants with low to medium effect sizes. As genotype data are high-dimensional in nature, it is crucial to develop methods that can be applied to large-scale data (largen $$ n $$ and largep $$ p $$ ). Many PRS tools aggregate univariate summary statistics from genome-wide association studies into a single score. Recent advancements allow simultaneous modeling of variant effects from individual-level genotype data. In this context, we introduced snpboost, an algorithm that applies statistical boosting on individual-level genotype data to estimate PRS via multivariable regression models. By processing variants iteratively in batches, snpboost can deal with large-scale cohort data. Having solved the technical obstacles due to data dimensionality, the methodological scope can now be broadened-focusing on key objectives for the clinical application of PRS. Similar to most methods in this context, snpboost has, so far, been restricted to quantitative and binary traits. Now, we incorporate more advanced alternatives-targeted to the particular aim and outcome. Adapting the loss function extends the snpboost framework to further data situations such as time-to-event and count data. Furthermore, alternative loss functions for continuous outcomes allow us to focus not only on the mean of the conditional distribution but also on other aspects that may be more helpful in the risk stratification of individual patients and can quantify prediction uncertainty, for example, median or quantile regression. This work enhances PRS fitting across multiple model classes previously unfeasible for this data type.

Genetic background of pulmonary (vascular) diseases - how much is written in the codes?

PURPOSE OF REVIEW

To provide a comprehensive overview of the underlying genetic defects of pulmonary (vascular) diseases and novel treatment avenues.

RECENT FINDINGS

Pulmonary arterial hypertension (PAH) is the prime example of a pulmonary vascular disease, which can be caused by genetic mutations in some patients. Germline mutations in the BMPR2 gene and further genes lead to vessel remodelling, increase of pulmonary vascular resistance and onset of heritable PAH. The PAH genes with the highest evidence and strategies for genetic testing and counselling have been assessed and evaluated in 2023 by international expert consortia. Moreover, first treatment options have just arisen targeting the molecular basis of PAH.

SUMMARY

Apart from PAH, this review touches on the underlying genetic causes of further lung diseases including alpha 1 antitrypsin deficiency, cystic fibrosis, familial pulmonary fibrosis and lymphangioleiomyomatosis. We point out the main disease genes, the underlying pathomechanisms and novel therapies trying not only to relieve symptoms but to treat the molecular causes of the diseases.

Early life exposures of childhood asthma and allergies-an epidemiologic perspective

Children around the world are continuing to develop and suffer from chronic lung diseases such as asthma. Childhood asthma commonly presents with recurrent episodes of cough, shortness of breath, and wheezing, all of which can lead to missed school days and hospitalization admissions. The role of environmental pollutants and aeroallergens has been increasingly recognized in relation to asthma etiology. We showcase the impacts of air pollution and pollen exposures in early life on childhood asthma and allergies through an epidemiologic perspective. We also examine the effects of indoor microbial exposures such as endotoxin and glucan on allergic diseases in schoolchildren as many spend most of their time in a household or classroom setting. Findings of this work can assist in the identification of key environmental factors in critical life periods and improve clinicians' diagnoses of asthma during early childhood.

Sex-specific alterations in the gut and lung microbiome of allergen-induced mice

Introduction

Recent evidence has demonstrated that the microbiome is a driver of the underlying pathophysiological mechanisms of respiratory disease. Studies have indicated that bacterial metabolites produced in the gut and lung can impact lung inflammation and immune cell activity, affecting disease pathology. Despite asthma being a disease with marked sex differences, experimental work linking microbiomes and asthma has not considered the sex variable.

Methods

To test the hypothesis that the lung and gut microbial composition impacts allergic lung inflammation in a sex-specific manner, we evaluated lung and gut microbiome alterations in a mouse model of allergic inflammation and assessed their association with lung function and inflammation phenotypes. For this, we exposed male and female adult C57BL/6J mice intranasally to 25 µg of a house dust mite extract mix (HDM) daily, or phosphate-buffered saline (PBS) as control, for 5 weeks (n = 4-6/group). DNA from fecal pellets collected before and after the 5-week treatment, and from lung tissue collected at endpoint, was extracted using the ZymoBIOMICS®-96 MagBead DNA Kit and analyzed to determine the 16S microbiome via Targeted Metagenomic Sequencing.

Results

The HDM treatment induced a sex-specific allergic inflammation phenotype with significantly higher neutrophilia, lymphocytosis, inflammatory gene expression, and histopathological changes in females than males following exposure to HDM, but higher airway hyperresponsiveness (AHR) in males than females. In addition, sex-specific lung gene expression and associated pathways were identified HDM mix after challenge. These changes corresponded to sex-specific alterations in the gut microbiome, where the Firmicutes to Bacteroidetes ratio (F:B) was significantly reduced in fecal samples from only male mice after HDM challenge, and alpha diversity was increased in males, but decreased in females, after 5-weeks of HDM treatment.

Discussion

Overall, our findings indicate that intranasal allergen challenge triggers sex-specific changes in both gut and lung microbiomes, and induces sex-specific lung inflammation, AHR, and lung inflammatory gene expression pathways, suggesting a contribution of the lung-gut axis in allergic airway disease.

Recommendations for Clinicians to Combat Environmental Disparities in Pediatric Asthma: A Review

TOPIC IMPORTANCE

Asthma is a common and complex lung disease in children, with disproportionally higher prevalence and related adverse outcomes among children in racial and ethnic minority groups, and of lower socioeconomic position. Environmental factors, including unhealthy housing and school-based exposures, can contribute to increased asthma morbidity and widening disparities. This underscores a significant environmental justice issue and suggests the need for clinical interventions to reduce sources of environmental exposures and ultimately diminish the observed disparities in childhood asthma.

REVIEW FINDINGS

Unhealthy housing conditions, including secondhand tobacco smoke, allergen exposure, and indoor air pollution, can exacerbate asthma symptoms in children. Although unhealthy housing can occur anywhere, such situations most frequently occur in urban, low-income environments where renting is common. To reduce environmental triggers, clinicians can recommend smoking cessation, cleaning techniques to mitigate exposure, and even directly contacting landlords to address poor housing conditions. Children spend much of their time in schools, where this built environment is also a source of asthma triggers (eg, poor ventilation) and allergens (eg, mold and pests, chemicals). As such, a multidisciplinary approach is needed to adequately address the burden of childhood asthma to equitably reduce disparities to both harmful exposures and negative health outcomes.

SUMMARY

Racial, ethnic, and socioeconomic disparities exist in asthma morbidity in children, and such disparities are driven in part by environmental factors at the housing and school level. Clinicians can make evidence-based recommendations to drive effective exposure reduction strategies to mitigate asthma morbidity and reduce observed disparities.

Impact of Interleukin-17 Receptor A Gene Variants on Asthma Susceptibility and Clinical Manifestations in Children and Adolescents

Several single nucleotide polymorphisms (SNPs) in multiple interleukin receptor genes could be associated with asthma risk and/or phenotype. Interleukin-17 (IL-17) has been implicated in tissue inflammation and autoimmune diseases. As no previous studies have uncovered the potential role of IL17 receptor A (RA) gene variants in asthma risk, we aimed to explore the association of four IL17RA SNPs (i.e., rs4819554A/G, rs879577C/T, rs41323645G/A, and rs4819555C/T) with asthma susceptibility/phenotype in our region. TaqMan allelic discrimination analysis was used to genotype 192 individuals. We found that the rs4819554 G/G genotype significantly reduced disease risk in the codominant (OR = 0.15, 95%CI = 0.05-0.45, p < 0.001), dominant (OR = 0.49, 95%CI = 0.26-0.93, p = 0.028), and recessive (OR = 0.18, 95%CI = 0.07-0.52, p < 0.001) models. Similarly, rs879577 showed reduced disease risk associated with the T allele across all genetic models. However, the A allele of rs41323645 was associated with increased disease risk in all models. The G/A and A/A genotypes have higher ORs of 2.47 (95%CI = 1.19-5.14) and 3.86 (95%CI = 1.62-9.18), respectively. Similar trends are observed in the dominant 2.89 (95%CI = 1.47-5.68, p = 0.002) and recessive 2.34 (95%CI = 1.10-4.98, p = 0.025) models. For the rs4819555 variant, although there was no significant association identified under any models, carriers of the rs4819554*A demonstrated an association with a positive family history of asthma (71.4% in carriers vs. 27% in non-carriers; p = 0.025) and the use of relievers for >2 weeks (52.2% of carriers vs. 28.8% of non-carriers; p = 0.047). Meanwhile, the rs4819555*C carriers displayed a significant divergence in the asthma phenotype, specifically atopic asthma (83.3% vs. 61.1%; p = 0.007), showed a higher prevalence of chest tightness (88.9% vs. 61.5%; p = 0.029), and were more likely to report comorbidities (57.7% vs. 16.7%, p = 0.003). The most frequent haplotype in the asthma group was ACAC, with a frequency of 22.87% vs. 1.36% in the controls (p < 0.001). In conclusion, the studied IL17RA variants could be essential in asthma susceptibility and phenotype in children and adolescents.

Asthma prevalence among United States population insights from NHANES data analysis

Asthma is a prevalent respiratory condition that poses a substantial burden on public health in the United States. Understanding its prevalence and associated risk factors is vital for informed policymaking and public health interventions. This study aims to examine asthma prevalence and identify major risk factors in the U.S.

POPULATION

Our study utilized NHANES data between 1999 and 2020 to investigate asthma prevalence and associated risk factors within the U.S.

POPULATION

We analyzed a dataset of 64,222 participants, excluding those under 20 years old. We performed binary regression analysis to examine the relationship of demographic and health related covariates with the prevalence of asthma. The study found that asthma affected 8.7% of the U.S.

POPULATION

Gender emerged as a significant factor, with 36.0% of asthma patients being male and 64.0% female (p < 0.001). Individuals aged 60 and older having the highest asthma prevalence at 34.0%. Non-Hispanic whites had the highest prevalence at 46.4%, followed by non-hispanic blacks at 26.0%. In contrast, Mexican Americans and other hispanic individuals had lower rates, at 9.6% and 9.0%, respectively. Females were 1.76 times more likely to have asthma than males (p < 0.001). Obese individuals had a 1.74 times higher likelihood of current asthma compared to underweight individuals (p < 0.001). Notably, both Non-Hispanic Whites and Non-Hispanic Blacks showed higher odds of current asthma compared to Mexican Americans (with adjusted odds ratios of 2.084 and 2.096, respectively, p < 0.001). The research findings indicate that asthma is prevalent in 8.7% of the U.S.

POPULATION

Our study highlights that individuals who are female, have low income, are obese, and smoke have the highest likelihood of being affected by asthma. Therefore, public health policies should prioritize addressing these risk factors in their preventive strategies.

Metabolite signatures associated with microRNA miR-143-3p serve as drivers of poor lung function trajectories in childhood asthma

BACKGROUND

Lung function trajectories (LFTs) have been shown to be an important measure of long-term health in asthma. While there is a growing body of metabolomic studies on asthma status and other phenotypes, there are no prospective studies of the relationship between metabolomics and LFTs or their genomic determinants.

METHODS

We utilized ordinal logistic regression to identify plasma metabolite principal components associated with four previously-published LFTs in children from the Childhood Asthma Management Program (CAMP) (n = 660). The top significant metabolite principal component (PCLF) was evaluated in an independent cross-sectional child cohort, the Genetic Epidemiology of Asthma in Costa Rica Study (GACRS) (n = 1151) and evaluated for association with spirometric measures. Using meta-analysis of CAMP and GACRS, we identified associations between PCLF and microRNA, and SNPs in their target genes. Statistical significance was determined using an false discovery rate-adjusted Q-value.

FINDINGS

The top metabolite principal component, PCLF, was significantly associated with better LFTs after multiple-testing correction (Q-value = 0.03). PCLF is composed of the urea cycle, caffeine, corticosteroid, carnitine, and potential microbial (secondary bile acid, tryptophan, linoleate, histidine metabolism) metabolites. Higher levels of PCLF were also associated with increases in lung function measures and decreased circulating neutrophil percentage in both CAMP and GACRS. PCLF was also significantly associated with microRNA miR-143-3p, and SNPs in three miR-143-3p target genes; CCZ1 (P-value = 2.6 × 10-5), SLC8A1 (P-value = 3.9 × 10-5); and TENM4 (P-value = 4.9 × 10-5).

INTERPRETATION

This study reveals associations between metabolites, miR-143-3p and LFTs in children with asthma, offering insights into asthma physiology and possible interventions to enhance lung function and long-term health.

FUNDING

Molecular data for CAMP and GACRS via the Trans-Omics in Precision Medicine (TOPMed) program was supported by the National Heart, Lung, and Blood Institute (NHLBI).

Risk of atopic dermatitis and the atopic march paradigm in children of mothers with atopic illnesses: A birth cohort study from the United Kingdom

BACKGROUND

Atopic dermatitis (AD) is thought to precede the onset of other allergic illness (OAI) in a temporal progression (ie, atopic march), yet the timing and progression has been questioned. It is also unclear how parental allergic illness impacts the development of these illnesses in offspring.

OBJECTIVE

(1) Explore risk of incident AD and (2) timing of allergic disease onset in children of mothers with AD compared with mothers without AD from the United Kingdom.

METHODS

We created a birth cohort of mother-child pairs using IQVIA Medical Research Data database and developed Cox proportional models to examine the above associations (hazard ratio, HR [95% confidence interval, CI]).

RESULTS

Among 1,224,243 child-mother pairs, mean child (standard deviation) follow-up time was 10.8 (8.3) years and 50.1% were males (N = 600,905). Children were 59% (HR = 1.59 [1.57, 1.60]) more likely to have AD if their mothers had AD compared with no AD with mean age of first AD diagnosis at 3.3 (4.8) years. Most children with any diagnosis of AD present with AD first (91.0%); however, in those with asthma, only 67.8% developed AD first.

CONCLUSION

Children born to mothers with AD are more prone to develop AD and some develop OAI first, suggesting that not all follow the same sequential pathway.

Breath of Change: Evaluating Asthma Information on TikTok and Introducing the Video Health Information Credibility Score

Introduction Asthma's global prevalence underscores the need for accessible health information dissemination, especially in the digital age. TikTok, known for its wide reach and diverse content, presents both opportunities and challenges in health information dissemination. This study aims to characterize the quality and reach of asthma-related content on TikTok and introduces the Video Health Information Credibility Score (VHICS) as a novel tool for quality assessment. Materials and methods We used a systematic methodology to analyze the top 100 TikTok videos by the number of likes tagged with #asthma. Data were collected in June 2023 and January 2024 to allow for temporal trend analysis. Videos were evaluated based on engagement metrics (views, likes, comments, shares, and favorites) and quality using the DISCERN instrument. Results Our analysis showed that physician-generated content accounted for a significant proportion of asthma-related videos, with varying levels of engagement. The DISCERN scores, with a range of 1 (lowest) to 5 highest), provided insights into content quality, revealing trends in user engagement and information reliability over time. Temporal analysis indicated changes in content creation and audience interaction. Discussion The study highlights the evolving landscape of digital health communication on TikTok. The introduction of VHICS added depth to the quality assessment of future directions, indicating the necessity for accurate and reliable health information on social media. The findings suggest an imperative for healthcare professionals to address misinformation and leverage digital platforms for patient education effectively. Conclusions TikTok is a significant medium for health information dissemination, with substantial potential for impact in patient education. The introduction of VHICS can enrich the analysis of video content, offering a robust tool for assessing the quality of health information on social media. This study underscores the importance of credible, clear, and audience-relevant health communication in the digital era.

Association of polymorphisms of vitamin D gene in children with asthma and allergic rhinitis - Hospital based study

Vitamin D gene polymorphisms are known to be associated with asthma and allergic rhinitis in children. However, the genetic association of the same in South Indian children with above condition is still unknown. The present study was designed with the objective to analyze the association of polymorphisms of vitamin D receptor gene (VDR) (rs797532, rs154410, rs2258470, rs731236) and transport gene of vitamin D (rs7041) in children with asthma and allergic rhinitis in South India. Children (1-18years) presenting with symptoms suggestive of asthma and allergic rhinitis to hospital based outpatient department, in Vellore, South India were recruited as cases and children presenting with minor illness without respiratory complaints were enrolled as controls during January 2018 to September 2021. Polymorphisms were genotyped using tetra-arms PCR. Significant increase in levels of absolute eosinophil counts and serum IgE levels with decrease in vitamin D levels was seen among the cases. Significant association between levels of vitamin D and serum IgE was also observed. Analysis of polymorphisms showed that, in comparison to homozygous major allele the odds of having heterozygous (OR0.55 (0.3, 0.99) and homozygous minor form (OR0.52 (0.28, 0.97) of rs7975232, homozygous minor (OR 0.51 (0.34, 0.76)) and alternate allele (OR 0.7 (0.53, 0.93)) of rs154410 and homozygous minor form (OR 0.57 (0.37, 0.88) of rs731236 was significantly lesser among the cases. Genotypic model of rs154410 (p0.023) and allele form of rs7041 (p 0.041) were significantly associated with vitamin D levels however no association of gene blocks with cases was seen in haplotype analysis. There was an apparent gene pool difference noted in comparative analysis between Indian studies. The study is the first in south India to analyze levels of serum IgE, Vitamin D levels, association of VDR polymorphisms, and rs7041 in children with asthma.

Causal relationship between asthma and ulcerative colitis and the mediating role of interleukin-18: a bidirectional Mendelian study and mediation analysis

Objective

Numerous observational investigations have documented a correlation between asthma and ulcerative colitis(UC). In this Mendelian Randomization (MR) study, we utilized extensive summary data from Genome-Wide Association Studies (GWAS) to further estimate the association between adult-onset asthma and the risk of UC, and to investigate the role of Interleukin-18 (IL-18) as a potential mediator.

Materials and methods

A two-step, two-sample MR study was conducted through mediation analysis. For this study, we employed a two-sample MR analysis using the inverse variance-weighted (IVW), weighted median, weighted mode, and MR-Egger regression techniques. We utilized publicly accessible summary statistics from a GWAS meta-analysis of adult-onset asthma in the UK Biobank (n=327,253; cases=26,582; controls=300,671) as the exposure factor. The outcomes were derived from GWAS data of individuals with European ancestry (n=26,405; cases=6,687; controls=19,718). GWAS data for IL-18 were obtained from individuals of European ancestry (n=9,785,222; cases=3,636; controls=9,781,586).

Results

The MR analysis indicates that adult-onset asthma is associated with an increased risk of UC, with an odds ratio (OR) of 1.019 (95% CI 1.001-1.045, P=0.006). However, there is no strong evidence to suggest that UC significantly impacts the risk of adult-onset asthma. IL-18 may act as a potential mediator in the causal relationship between adult-onset asthma and UC, with a mediation proportion of 3.9% (95% CI, 0.6%-6.9%).

Conclusion

In summary, our study established a causal relationship between asthma and UC, in which IL-18 contributes to a small extent. However, the primary factors underlying the influence of asthma on UC remain unclear. Future research should focus on identifying other potential mediators. In clinical practice, it is important to pay greater attention to intestinal lesions in patients with asthma.

Automated detection of airflow obstructive diseases: A systematic review of the last decade (2013-2022)

BACKGROUND AND OBJECTIVE

Obstructive airway diseases, including asthma and Chronic Obstructive Pulmonary Disease (COPD), are two of the most common chronic respiratory health problems. Both of these conditions require health professional expertise in making a diagnosis. Hence, this process is time intensive for healthcare providers and the diagnostic quality is subject to intra- and inter- operator variability. In this study we investigate the role of automated detection of obstructive airway diseases to reduce cost and improve diagnostic quality.

METHODS

We investigated the existing body of evidence and applied Preferred Reporting Items for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to search records in IEEE, Google scholar, and PubMed databases. We identified 65 papers that were published from 2013 to 2022 and these papers cover 67 different studies. The review process was structured according to the medical data that was used for disease detection. We identified six main categories, namely air flow, genetic, imaging, signals, and miscellaneous. For each of these categories, we report both disease detection methods and their performance.

RESULTS

We found that medical imaging was used in 14 of the reviewed studies as data for automated obstructive airway disease detection. Genetics and physiological signals were used in 13 studies. Medical records and air flow were used in 9 and 7 studies, respectively. Most papers were published in 2020 and we found three times more work on Machine Learning (ML) when compared to Deep Learning (DL). Statistical analysis shows that DL techniques achieve higher Accuracy (ACC) when compared to ML. Convolutional Neural Network (CNN) is the most common DL classifier and Support Vector Machine (SVM) is the most widely used ML classifier. During our review, we discovered only two publicly available asthma and COPD datasets. Most studies used private clinical datasets, so data size and data composition are inconsistent.

CONCLUSIONS

Our review results indicate that Artificial Intelligence (AI) can improve both decision quality and efficiency of health professionals during COPD and asthma diagnosis. However, we found several limitations in this review, such as a lack of dataset consistency, a limited dataset and remote monitoring was not sufficiently explored. We appeal to society to accept and trust computer aided airflow obstructive diseases diagnosis and we encourage health professionals to work closely with AI scientists to promote automated detection in clinical practice and hospital settings.

Causal relationship between Butyricimonas and allergic asthma: a two-sample Mendelian randomization study

Background

Growing evidence has well documented the close association between the gut microbiome and allergic respiratory disease, which has been notably represented by allergic asthma. However, it is unclear whether this association is a causal link. Therefore, we investigated the potential causal associations between the gut microbiome and allergic asthma or other allergic diseases.

Methods

In this study, we performed two-sample Mendelian randomization (MR) analyses by using the publicly available genome-wide association study (GWAS) summary data. Single-nucleotide polymorphisms (SNPs) that significantly correlated were selected as instrumental variables. The inverse variance weighted (IVW) method was used to examine the potential causal gut microbial genera for allergic asthma and other allergic diseases. The robustness of the primary findings of the MR analyses was ensured by using different sensitivity analyses.

Results

Combining the findings from multiple analyses, the host genetic-driven increases in Butyricimonas at the genus level were positively correlated with the risk of allergic asthma. In addition, phylum Bacteroidetes and class Bacteroidia were also found to have negative associations with the risk of allergic asthma; genus Slackia was identified as having potential causal effects with allergic asthma. No clear evidence of pleiotropy and heterogeneity was observed in genus Butyricimonas. Butyricimonas was also found to have an association with allergic rhinitis, but not with other allergic diseases.

Conclusion

Our findings indicate that there are new gut microbial genera that were causally associated with the risk of allergic asthma and other allergic diseases, and offer novel insights into the pathogenesis of allergic respiratory diseases.

GEMA 5.3. Spanish Guideline on the Management of Asthma

The Spanish Guideline on the Management of Asthma, better known by its acronym in Spanish GEMA, has been available for more than 20 years. Twenty-one scientific societies or related groups both from Spain and internationally have participated in the preparation and development of the updated edition of GEMA, which in fact has been currently positioned as the reference guide on asthma in the Spanish language worldwide. Its objective is to prevent and improve the clinical situation of people with asthma by increasing the knowledge of healthcare professionals involved in their care. Its purpose is to convert scientific evidence into simple and easy-to-follow practical recommendations. Therefore, it is not a monograph that brings together all the scientific knowledge about the disease, but rather a brief document with the essentials, designed to be applied quickly in routine clinical practice. The guidelines are necessarily multidisciplinary, developed to be useful and an indispensable tool for physicians of different specialties, as well as nurses and pharmacists. Probably the most outstanding aspects of the guide are the recommendations to: establish the diagnosis of asthma using a sequential algorithm based on objective diagnostic tests; the follow-up of patients, preferably based on the strategy of achieving and maintaining control of the disease; treatment according to the level of severity of asthma, using six steps from least to greatest need of pharmaceutical drugs, and the treatment algorithm for the indication of biologics in patients with severe uncontrolled asthma based on phenotypes. And now, in addition to that, there is a novelty for easy use and follow-up through a computer application based on the chatbot-type conversational artificial intelligence (ia-GEMA).

Potential drug targets for asthma identified in the plasma and brain through Mendelian randomization analysis

Background

Asthma is a heterogeneous disease, and the involvement of neurogenic inflammation is crucial in its development. The standardized treatments focus on alleviating symptoms. Despite the availability of medications for asthma, they have proven to be inadequate in controlling relapses and halting the progression of the disease. Therefore, there is a need for novel drug targets to prevent asthma.

Methods

We utilized Mendelian randomization to investigate potential drug targets for asthma. We analyzed summary statistics from the UK Biobank and then replicated our findings in GWAS data by Demenais et al. and the FinnGen cohort. We obtained genetic instruments for 734 plasma and 73 brain proteins from recently reported GWAS. Next, we utilized reverse causal relationship analysis, Bayesian co-localization, and phenotype scanning as part of our sensitivity analysis. Furthermore, we performed a comparison and protein-protein interaction analysis to identify causal proteins. We also analyzed the possible consequences of our discoveries by the given existing asthma drugs and their targets.

Results

Using Mendelian randomization analysis, we identified five protein-asthma pairs that were significant at the Bonferroni level (P < 6.35 × 10-5). Specifically, in plasma, we found that an increase of one standard deviation in IL1R1 and ECM1 was associated with an increased risk of asthma, while an increase in ADAM19 was found to be protective. The corresponding odds ratios were 1.03 (95% CI, 1.02-1.04), 1.00 (95% CI, 1.00-1.01), and 0.99 (95% CI, 0.98-0.99), respectively. In the brain, per 10-fold increase in ECM1 (OR, 1.05; 95% CI, 1.03-1.08) and PDLIM4 (OR, 1.05; 95% CI, 1.04-1.07) increased the risk of asthma. Bayesian co-localization found that ECM1 in the plasma (coloc.abf-PPH4 = 0.965) and in the brain (coloc.abf-PPH4 = 0.931) shared the same mutation with asthma. The target proteins of current asthma medications were found to interact with IL1R1. IL1R1 and PDLIM4 were validated in two replication cohorts.

Conclusion

Our integrative analysis revealed that asthma risk is causally affected by the levels of IL1R1, ECM1, and PDLIM4. The results suggest that these three proteins have the potential to be used as drug targets for asthma, and further investigation through clinical trials is needed.

From gene identifications to therapeutic targets for asthma: Focus on great potentials of TSLP, ORMDL3, and GSDMB

Asthma is a chronic respiratory disease, and clinically, asthma exacerbations remain difficult to treat. The disease is caused by combinations of and interactions between genetic and environmental factors. Genomic and genetic approaches identified many novel genes to treat asthma and brought new insights into the disease. The products of the genes have functional roles in regulating physiological or pathophysiological processes in airway structural cells and immune system cells. Genetic factors also interact with environmental factors such as air pollutants, and bacterial and viral infections to trigger the disease. Thymic stromal lymphopoietin (TSLP), orosomucoid-like 3 (ORMDL3), and gasdermin B (GSDMB) are three genes identified by genetic studies to have a great potential as therapeutic targets of asthma. TSLP is an important driver of type 2 inflammation. ORMDL3 mediates cell stress, sphingolipid synthesis, and viral and bacterial infections. GSDMB regulates cell pyroptosis through its N and C terminals and can bind sulfatides to influence inflammatory response. Investigating inhibitors or modulators for these pathways would bring a new landscape for therapeutics of asthma in future.

A Review of the Epigenetic Clock: Emerging Biomarkers for Asthma and Allergic Disease

DNA methylation (DNAm) is a dynamic, age-dependent epigenetic modification that can be used to study interactions between genetic and environmental factors. Environmental exposures during critical periods of growth and development may alter DNAm patterns, leading to increased susceptibility to diseases such as asthma and allergies. One method to study the role of DNAm is the epigenetic clock-an algorithm that uses DNAm levels at select age-informative Cytosine-phosphate-Guanine (CpG) dinucleotides to predict epigenetic age (EA). The difference between EA and calendar age (CA) is termed epigenetic age acceleration (EAA) and reveals information about the biological capacity of an individual. Associations between EAA and disease susceptibility have been demonstrated for a variety of age-related conditions and, more recently, phenotypes such as asthma and allergic diseases, which often begin in childhood and progress throughout the lifespan. In this review, we explore different epigenetic clocks and how they have been applied, particularly as related to childhood asthma. We delve into how in utero and early life exposures (e.g., smoking, air pollution, maternal BMI) result in methylation changes. Furthermore, we explore the potential for EAA to be used as a biomarker for asthma and allergic diseases and identify areas for further study.

Comparative Dynamic Pulmonary Function Tests Between Apparently Healthy Young Adult Offspring of Asthmatic and Non-asthmatic Parents: A Pilot Study

Background While the hereditary component of asthma has been established, its influence on early respiratory function changes in otherwise healthy offspring remains to be explored. Dynamic lung function tests assess airflow in and out of the lungs, providing valuable insights into respiratory health and detecting potential airflow limitations. This study aimed to compare the dynamic lung functions between offspring of asthmatic and non-asthmatic parents. Methodology A case-control design was employed comprising 30 cases (offspring of asthmatic parents) and 30 controls (offspring of non-asthmatic parents). Lung function parameters including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, forced expiratory flow between 25% and 75% of the FVC (FEF 25-75%), and maximum mid-expiratory flow at 50% of the FVC (Vmax 50%) were measured. Statistical analysis was conducted to compare the parameters between cases and controls using the unpaired t-test. Results The mean age of controls was 20.46 ± 2.82 years and the cases was 19.83 ± 1.41 years. The study revealed that cases exhibited lower FEV1 and Vmax 50% values compared to controls, indicating potential airflow limitations and altered mid-exhalation flow rates in the offspring of asthmatic parents. While trends were observed in FVC, FEV1/FVC ratio, and FEF 25-75%, these differences were not statistically significant. Conclusions The findings suggest a potential association between parental asthma and altered lung function parameters, specifically in FEV1 and Vmax 50%, among their offspring. These early respiratory function changes underscore the potential impact of hereditary factors on lung health. Healthcare professionals should take parental asthma into account when evaluating lung functions. This may lead to earlier detection and intervention. Further investigation is warranted to elucidate the underlying mechanisms and long-term implications of these findings.

Long non coding RNAs reveal important pathways in childhood asthma: a future perspective

Asthma is a long-term inflammatory disease of the airways of the lungs refers changes that occur in conjunction with, or as a result of, chronic airway inflammation. Airway remodeling the subsequent of inflammation constitutes cellular and extracellular matrix changes in the wall airways, epithelial-to-mesenchymal-transition and airway smooth muscle cell proliferation. Diseases often begin in childhood and despite extensive research, causative pathogenic mechanisms still remain unclear. Transcriptome analysis of childhood asthma reveals distinct gene expression profiles of Long noncoding RNAs which have been reported to play a central regulatory role in various aspects of pathogenesis, clinical course and treatment of asthma. We briefly review current understanding of lnc-RNA dysregulation in children with asthma, focusing on their complex role in the inflammation, cell proliferation and remodeling of airway to guide future researches. We found that the lnc-RNAs increases activity of several oncogenes such c-Myc, Akt, and ERK and various signaling pathways such as MAPK (PI3K, Ras, JNK and p38), NF-κB and Wnt and crosstalk between these pathways by TGFβ, β-catenin, ERK and SKP2. Moreover, two different signal transduction pathways, Wnt and Notch1, can be activated by two lnc-RNAs through sponging the same miRNA for exacerbation cell proliferation.

Associations between interleukin 17A and 17F polymorphisms and asthma susceptibility: A meta-analysis

Owing to their role in inflammatory reactions and immunological responses as well as their chromosomal location, interleukin (IL) 17A and 17F are regarded as candidate causal genes associated with asthma. The aim of this study was to determine whether IL17 polymorphisms are associated with susceptibility to asthma. We used the PubMed/Medline and Embase databases to search for studies reporting IL17 polymorphisms in patients with asthma and healthy controls. Meta-analyses were conducted to determine the associations between IL17A rs8193036 (-737C/T), rs2275913 (-197G/A), rs3819024 (A/G), rs3748067 (C/T), and rs4711998 (A/G) and IL17F rs763780 (7488A/G), rs2397084 (T/C), rs1889570 (C/T), rs11465553 (G/A), and rs1266828 (T/C) polymorphisms and asthma susceptibility. A total of 20 studies were included in this meta-analysis. Our results revealed the IL17A rs8193036 CC genotype was associated with asthma susceptibility (odds ratio [OR] = 1.490, 95% confidence interval [CI] = 1.027-2.161, p = .036). However, stratification by ethnicity indicated no association between this polymorphism and asthma in European and Asian subjects. Furthermore, no association was found between this polymorphism and asthma using the allele contrast, dominant or homozygous contrast models. No evidence of an association was found between any of the other IL17A and IL17F polymorphisms and asthma susceptibility in this meta-analysis. This meta-analysis showed that, among the studied polymorphisms, only the CC genotype of IL17A rs8193036 is associated with asthma susceptibility.

In vitro human cell-based models to study airway remodeling in asthma

Airway remodeling, as a predominant characteristic of asthma, refers to the structural changes that occurred both in the large and small airways. These pathological changes not only contribute to airway hyperresponsiveness and airway obstruction, but also predict poor outcomes of patients. In vitro models are the alternatives to animal models that facilitate airway remodeling research. Current approaches to mimic airway remodeling in vitro include mono cultures of cell lines and primary cells that are derived from the respiratory tract, and co-culture systems that consist of different cell subpopulations. Moreover, recent advances in microfluid chips and organoids show promise in simulating the complex architecture and functionality of native organs. According, they enable highly physiological-relevant investigations of human diseases in vitro. Here we aim to detail the current human cell-based models regarding their key pros and cons, and to discuss how they may be used to facilitate our understanding of airway remodeling in asthma.

Metabolomics of asthma, COPD, and asthma-COPD overlap: an overview

The two common progressive lung diseases, asthma and chronic obstructive pulmonary disease (COPD), are the leading causes of morbidity and mortality worldwide. Asthma-COPD overlap, referred to as ACO, is another complex pulmonary disease that manifests itself with features of both asthma and COPD. The disease has no clear diagnostic or therapeutic guidelines, thereby making both diagnosis and treatment challenging. Though a number of studies on ACO have been documented, gaps in knowledge regarding the pathophysiologic mechanism of this disorder exist. Addressing this issue is an urgent need for improved diagnostic and therapeutic management of the disease. Metabolomics, an increasingly popular technique, reveals the pathogenesis of complex diseases and holds promise in biomarker discovery. This comprehensive narrative review, comprising 99 original research articles in the last five years (2017-2022), summarizes the scientific advances in terms of metabolic alterations in patients with asthma, COPD, and ACO. The analytical tools, nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), and liquid chromatography-mass spectrometry (LC-MS), commonly used to study the expression of the metabolome, are discussed. Challenges frequently encountered during metabolite identification and quality assessment are highlighted. Bridging the gap between phenotype and metabotype is envisioned in the future.

The Role of Systems Biology in Deciphering Asthma Heterogeneity

Asthma is one of the most common and lifelong and chronic inflammatory diseases characterized by inflammation, bronchial hyperresponsiveness, and airway obstruction episodes. It is a heterogeneous disease of varying and overlapping phenotypes with many confounding factors playing a role in disease susceptibility and management. Such multifactorial disorders will benefit from using systems biology as a strategy to elucidate molecular insights from complex, quantitative, massive clinical, and biological data that will help to understand the underlying disease mechanism, early detection, and treatment planning. Systems biology is an approach that uses the comprehensive understanding of living systems through bioinformatics, mathematical, and computational techniques to model diverse high-throughput molecular, cellular, and the physiologic profiling of healthy and diseased populations to define biological processes. The use of systems biology has helped understand and enrich our knowledge of asthma heterogeneity and molecular basis; however, such methods have their limitations. The translational benefits of these studies are few, and it is recommended to reanalyze the different studies and omics in conjugation with one another which may help understand the reasons for this variation and help overcome the limitations of understanding the heterogeneity in asthma pathology. In this review, we aim to show the different factors that play a role in asthma heterogeneity and how systems biology may aid in understanding and deciphering the molecular basis of asthma.

Ambient Air Pollutants and Traffic Factors Were Associated with Blood and Urine Biomarkers and Asthma Risk

The UK Biobank (UKBB) is a large population-based cohort that provides a unique opportunity to study the association between environmental exposure and biomarkers and to identify biomarkers as potential instruments for assessing exposure dose, health damage, and disease risks. On 462 063 participants of European ancestry, we characterized the relationship of 38 disease-relevant biomarkers, asthma diagnosis, ambient pollution, traffic factors, and genetic background. The air pollutant exposure on the UKBB cohort was fairly low (e.g., mean PM_2.5 concentration at 10.0 μg/m³). Nevertheless, 30 biomarkers were in association with at least one environmental factor; e.g., C-reactive protein levels were positively associated with NO (p_adj = 2.99 × 10^-4), NO₂ (p_adj = 4.15 × 10^-4), and PM_2.5 (p_adj = 1.92 × 10^-6) even after multiple testing adjustment. Asthma diagnosis was associated with four pollutants (NO, NO₂, PM_2.5, and PM₁₀). The largest effect size was observed in PM_2.5, where a 5 μg/m³ increment of exposure was associated with a 1.52 increase in asthma diagnosis (p = 4.41 × 10^-13). Further, environmental exposure and genetic predisposition influenced biomarker levels and asthma diagnosis in an additive model. The exposure-biomarker associations identified in this study could serve as potential indicators for environmental exposure induced health damages. Our results also shed light on possible mechanisms whereby environmental exposure influences disease-causing biomarkers and in turn increases disease risk.

[Genetic aspects involved in asthma]

Asthma is an etiologically heterogeneous disease resulting from a complex interaction between genetic. The genetic aspects involved in asthma, which were analyzed from the perspective of the traditional model of multifactorial inheritance, were susceptibility, host factors, and environmental exposures. In the present paper, studies on their family aggregation, concordance in twins, and heritability were analized; as well as the current knowledge about candidate genes, genome wide association studies, and epigenomics contributions and other omic studies that have increased our knowledge about their pathophysiology and environmental interactions.

Nasal Microbiome Change During and After Exacerbation in Asthmatic Children

Airway and gut microbiota are important in asthma pathogenesis. Although several studies have revealed distinct microbiota in asthmatic airways at baseline compared to healthy controls, limited studies compared microbiota during acute exacerbation (AE) and in the recovery phase (RP) in the same asthmatic children. We aim to investigate association between microbiota and asthma status in children and explore their relationship with clinical features of asthma. We recruited 56 asthmatic children and investigated their nasal, throat, and stool microbiota during AE and in the RP. Totally, 320 samples were subjected to 16S rRNA sequencing. Although the microbial communities were clearly separated by body site, within each site the overall communities during AE and in the RP could not be distinguished. Most nasal microbiota were dominated by only one or two of six bacterial genera. The domination was associated with mite allergy and patient age only during AE but not in the RP. When moving into RP, the relative abundance of Staphylococcus increased while that of Moraxella decreased. Throat and stool microbiota were not associated with most of the clinical features. Interestingly, stool microbiota during AE was associated with ABO blood type and stool microbiota in the RP was associated with frequency of the subsequent exacerbations. In summary, the association between nasal microbiota and mite allergy only during AE suggests an altered local immunity and its interplay with nasal microbes. Our work provides a basis for studying microbes, and prevention or therapeutic strategy in childhood asthma, especially during AE.

Persistence of parental-reported asthma at early ages: A longitudinal twin study

BACKGROUND

Currently, we cannot predict whether a pre-school child with asthma-like symptoms will have asthma at school age. Whether genetic information can help in this prediction depends on the role of genetic factors in persistence of pre-school to school-age asthma. We examined to what extent genetic and environmental factors contribute to persistence of asthma-like symptoms at ages 3 to asthma at age 7 using a bivariate genetic model for longitudinal twin data.

METHODS

We performed a cohort study in monozygotic and dizygotic twins from the Netherlands Twin Register (NTR, n = 21,541 twin pairs). Bivariate genetic models were fitted to longitudinal data on asthma-like symptoms reported by parents at age 3 and 7 years to estimate the contribution of genetic and environmental factors.

RESULTS

Bivariate genetic modeling showed a correlation on the liability scale between asthma-like symptoms at age 3 and asthma at age 7 of 0.746 and the contribution of genetics was estimated to be 0.917. The genetic analyses indicated a substantial influence of genetic factors on asthma-like symptoms at ages 3 and 7 (heritability 80% and 90%, respectively); hence, contribution of environmental factors was low. Persistence was explained by a high (rg = 0.807) genetic correlation.

CONCLUSION

Parental-reported asthma-like symptoms at age 3 and asthma at age 7 are highly heritably. The phenotype of asthma-like symptoms at age 3 and 7 was highly correlated and mainly due to heritable factors, indicating high persistence of asthma development over ages 3 and 7.

Emerging Roles of Non-Coding RNAs in Childhood Asthma

Asthma is a chronic airway inflammatory disease in children characterized by airway inflammation, airway hyperresponsiveness and airway remodeling. Childhood asthma is usually associated with allergy and atopy, unlike adult asthma, which is commonly associated with obesity, smoking, etc. The pathogenesis and diagnosis of childhood asthma also remains more challenging than adult asthma, such as many diseases showing similar symptoms may coexist and be confused with asthma. In terms of the treatment, although most childhood asthma can potentially be self-managed and controlled with drugs, approximately 5-10% of children suffer from severe uncontrolled asthma, which carries significant health and socioeconomic burdens. Therefore, it is necessary to explore the pathogenesis of childhood asthma from a new perspective. Studies have revealed that non-coding RNAs (ncRNAs) are involved in the regulation of respiratory diseases. In addition, altered expression of ncRNAs in blood, and in condensate of sputum or exhalation affects the progression of asthma via regulating immune response. In this review, we outline the regulation and pathogenesis of asthma and summarize the role of ncRNAs in childhood asthma. We also hold promise that ncRNAs may be used for the development of biomarkers and support a new therapeutic strategy for childhood asthma.

Network and co-expression analysis of airway smooth muscle cell transcriptome delineates potential gene signatures in asthma

Airway smooth muscle (ASM) is known for its role in asthma exacerbations characterized by acute bronchoconstriction and remodeling. The molecular mechanisms underlying multiple gene interactions regulating gene expression in asthma remain elusive. Herein, we explored the regulatory relationship between ASM genes to uncover the putative mechanism underlying asthma in humans. To this end, the gene expression from human ASM was measured with RNA-Seq in non-asthmatic and asthmatic groups. The gene network for the asthmatic and non-asthmatic group was constructed by prioritizing differentially expressed genes (DEGs) (121) and transcription factors (TFs) (116). Furthermore, we identified differentially connected or co-expressed genes in each group. The asthmatic group showed a loss of gene connectivity due to the rewiring of major regulators. Notably, TFs such as ZNF792, SMAD1, and SMAD7 were differentially correlated in the asthmatic ASM. Additionally, the DEGs, TFs, and differentially connected genes over-represented in the pathways involved with herpes simplex virus infection, Hippo and TGF-β signaling, adherens junctions, gap junctions, and ferroptosis. The rewiring of major regulators unveiled in this study likely modulates the expression of gene-targets as an adaptive response to asthma. These multiple gene interactions pointed out novel targets and pathways for asthma exacerbations.

The Role of Upper Airway Microbiome in the Development of Adult Asthma

Clinical and molecular phenotypes of asthma are complex. The main phenotypes of adult asthma are characterized by eosinophil and/or neutrophil cell dominant airway inflammation that represent distinct clinical features. Upper and lower airways constitute a unique system and their interaction shows functional complementarity. Although human upper airway contains various indigenous commensals and opportunistic pathogenic microbiome, imbalance of this interactions lead to pathogen overgrowth and increased inflammation and airway remodeling. Competition for epithelial cell attachment, different susceptibilities to host defense molecules and antimicrobial peptides, and the production of proinflammatory cytokine and pattern recognition receptors possibly determine the pattern of this inflammation. Exposure to environmental factors, including infection, air pollution, smoking is commonly associated with asthma comorbidity, severity, exacerbation and resistance to anti-microbial and steroid treatment, and these effects may also be modulated by host and microbial genetics. Administration of probiotic, antibiotic and corticosteroid treatment for asthma may modify the composition of resident microbiota and clinical features. This review summarizes the effect of some environmental factors on the upper respiratory microbiome, the interaction between host-microbiome, and potential impact of asthma treatment on the composition of the upper airway microbiome.

Breathlessness across generations: results from the RHINESSA generation study

Background

Breathlessness is a major cause of suffering and disability globally. The symptom relates to multiple factors including asthma and lung function, which are influenced by hereditary factors. No study has evaluated potential inheritance of breathlessness itself across generations.

Methods

We analysed the association between breathlessness in parents and their offspring in the Respiratory Health in Northern Europe, Spain and Australia generation study. Data on parents and offspring aged ≥18 years across 10 study centres in seven countries included demographics, self-reported breathlessness, asthma, depression, smoking, physical activity level, measured Body Mass Index and spirometry. Data were analysed using multivariable logistic regression accounting for clustering within centres and between siblings.

Results

A total of 1720 parents (mean age at assessment 36 years, 55% mothers) and 2476 offspring (mean 30 years, 55% daughters) were included. Breathlessness was reported by 809 (32.7%) parents and 363 (14.7%) offspring. Factors independently associated with breathlessness in parents and offspring included obesity, current smoking, asthma, depression, lower lung function and female sex. After adjusting for potential confounders, parents with breathlessness were more likely to have offspring with breathlessness, adjusted OR 1.8 (95% CI 1.1 to 2.9). The association was not modified by sex of the parent or offspring.

Conclusion

Parents with breathlessness were more likely to have children who developed breathlessness, after adjusting for asthma, lung function, obesity, smoking, depression and female sex in both generations. The hereditary components of breathlessness need to be further explored.

COL4A3 expression in asthmatic epithelium depends on intronic methylation and ZNF263 binding

Background

Reduction of COL4A3, one of the six isoforms of collagen 4, in asthmatic airways results in increased inflammation and angiogenesis, implicating it as a central part of asthma pathogenesis. However, to date, the path underlying these diminished COL4A3 levels has been elusive. This study investigated a possible mechanism underlying the reduction of COL4A3 expression.

Methods

Bronchial biopsies of 76 patients with asthma and 83 controls were subjected to RNA-sequencing and DNA methylation bead arrays to identify expression and methylation changes. The binding of ZNF263 was analysed by chromatin-immunoprecipitation sequencing coupled with quantitative (q)PCR. Effects of ZNF263 silencing, using small interfering RNA, on the COL4A3 expression were studied using qPCR.

Results

COL4A3 expression was significantly reduced in bronchial biopsies compared to healthy controls, whereas DNA methylation levels at cg11797365 were increased. COL4A3 expression levels were significantly low in asthmatics without inhaled corticosteroid (ICS) use, whereas the expression was not statistically different between asthmatics using ICS and controls. Methylation levels at cg11797365 in vitro were increased upon consecutive rhinovirus infections.

Conclusion

Our data indicate an epigenetic modification as a contributing factor for the loss of COL4A3 expression in asthmatic airway epithelium.

An epigenetic modification interrupts ZNF263 binding, which may contribute to the loss of COL4A3 expression in asthmatic airway epitheliumhttps://bit.ly/39cZbyn

Genetic Determinants of Poor Response to Treatment in Severe Asthma

Severe asthma is a multifactorial disorder with marked phenotypic heterogeneity and complex interactions between genetics and environmental risk factors, which could, at least in part, explain why during standard pharmacologic treatment, many patients remain poorly controlled and at an increased risk of airway remodeling and disease progression. The concept of “precision medicine” to better suit individual unique needs is an emerging trend in the management of chronic respiratory diseases. Over the past few years, Genome-Wide Association Studies (GWAS) have revealed novel pharmacogenetic variants related to responses to inhaled corticosteroids and the clinical efficacy of bronchodilators. Optimal clinical response to treatment may vary between racial/ethnic groups or individuals due to genetic differences. It is also plausible to assume that epigenetic factors play a key role in the modulation of gene expression patterns and inflammatory cytokines. Remarkably, specific genetic variants related to treatment effectiveness may indicate promising pathways for novel therapies in severe asthma. In this review, we provide a concise update of genetic determinants of poor response to treatment in severe asthma and future directions in the field.

Early life blood lead levels and asthma diagnosis at age 4-6 years

The USA has a high burden of childhood asthma. Previous studies have observed associations between higher blood lead levels and greater hypersensitivity in children. The objective of the present study was to estimate the association between blood lead concentrations during early childhood and an asthma diagnosis between 48 and 72 months of age amongst a cohort with well-characterized blood lead concentrations. Blood lead concentrations were measured at 6, 12, 18, 24, 36, and 48 months of age in 222 children. The presence of an asthma diagnosis between 48 and 72 months was assessed using a questionnaire which asked parents or guardians whether they had been told by a physician, in the past 12 months, that their child had asthma. Crude and adjusted risk ratios (RR) of an asthma diagnosis were estimated for several parameterizations of blood lead exposure including lifetime average (6 to 48 months) and infancy average (6 to 24 months) concentrations. After adjustment for child sex, birthweight, daycare attendance, maternal race, education, parity, breastfeeding, income, and household smoking, age-specific or composite measures of blood lead were not associated with asthma diagnosis by 72 months of age in this cohort.

Functional abdominal pain disorders and asthma: two disorders, but similar pathophysiology?

INTRODUCTION

Functional abdominal pain disorders (FAPDs) and asthma are common ailments affecting both children and adults worldwide. Multiple studies have demonstrated an association between these two disorders. However, the exact reason for this observed association is not apparent.

AREAS COVERED

The current review has explored available literature and outlined multiple underlying pathophysiological mechanisms, common to both asthma and FAPDs, as possible reasons for this association.

EXPERT OPINION

Smooth muscle dysfunction, hypersensitivity and hyper-responsiveness, mucosal inflammation, and barrier dysfunction involving gastrointestinal and respiratory tracts are the main underlying pathophysiological mechanisms described for the generation of symptoms in FAPDs and asthma. In addition, alterations in neuroendocrine regulatory functions, immunological dysfunction, and microbial dysbiosis have been described in both disorders. We believe that the pathophysiological processes that were explored in this article would be able to expand the mechanisms of the association. The in-depth knowledge is needed to be converted to therapeutic and preventive strategies to improve the quality of care of children suffering from FAPDs and asthma.

Effects of low exposure to traffic related air pollution on childhood asthma onset by age 10 years

Although NO₂, a major traffic related air pollutant, has been associated with onset of childhood asthma, young children may be more susceptible to traffic related air pollution exposure compared to other individuals. We linked data from National Longitudinal Survey of Children and Youths Cycle 1-5 (1994-2003) and the National Air Pollution Surveillance Program to determine the association between NO₂ exposure and either early or late onset childhood asthma phenotypes. Children diagnosed with asthma from age 0-3 were defined as having early onset asthma. Children diagnosed with asthma from age 4-9 were defined as having late onset asthma. Mean NO₂ exposure for each quartile was 6.31 ppb, 9.45 ppb, 11.83 ppb, and 17.9 ppb. Higher levels of NO₂ exposure were more strongly associated with early childhood asthma (Quartile 3 OR: 2.11, 95% CI: 1.29, 3.44, Quartile 4 OR: 2.16, 95% CI: 1.27, 3.68) compared to the lowest level of NO₂ exposure (Quartile 1). No such association was observed with risk of late childhood asthma onset. Asthma susceptibility to NO₂ exposure may vary with the childhood developmental stage, and young children may be susceptible to NO₂ exposure at levels well below national and international guidelines. Our study emphasizes the importance of considering the timing of childhood asthma onset in future studies and confirms the increased risk of early onset of childhood asthma associated even with relatively low NO₂ exposure levels.

Blood and Salivary Amphiregulin Levels as Biomarkers for Asthma

Background: Amphiregulin (AREG) expression in asthmatic airways and sputum was shown to increase and correlate with asthma. However, no studies were carried out to evaluate the AREG level in blood and saliva of asthmatic patients. Objective: To measure circulating AREG mRNA and protein concentrations in blood, saliva, and bronchial biopsies samples from asthmatic patients. Methods: Plasma and Saliva AREG protein concentrations were measured using ELISA while PBMCs, and Saliva mRNA expression was measured by RT qPCR in non-severe, and severe asthmatic patients compared to healthy controls. Primary asthmatic bronchial epithelial cells and fibroblasts were assessed for AREG mRNA expression and released soluble AREG in their conditioned media. Tissue expression of AREG was evaluated using immunohistochemistry of bronchial biopsies from asthmatic patients and healthy controls. Publicly available transcriptomic databases were explored for the global transcriptomic profile of bronchial epithelium, and PBMCs were explored for AREG expression in asthmatic vs. healthy controls. Results: Asthmatic patients had higher AREG protein levels in blood and saliva compared to control subjects. Higher mRNA expression in saliva and primary bronchial epithelial cells plus higher AREG immunoreactivity in bronchial biopsies were also observed. Both blood and saliva AREG levels showed positive correlations with allergic rhinitis status, atopy status, eczema status, plasma periostin, neutrophilia, Montelukast sodium use, ACT score, FEV1, and FEV1/FVC. In silico analysis showed that severe asthmatic bronchial epithelium with high AREG gene expression is associated with higher neutrophils infiltration. Conclusion: AREG levels measured in a minimally invasive blood sample and a non-invasive saliva sample are higher in non-allergic severe asthma.

CLINICAL IMPLICATIONS

This is the first report to show the higher level of AREG levels in blood and saliva of non-allergic severe asthma.

A link among schizophrenia, diabetes, and asthma: Role of Ca2+/cAMP signaling

Asthma has been associated with an increased risk for developing schizophrenia. In addition, schizophrenia has been associated with an increased risk for developing type 2 diabetes mellitus, resulting in an elevated cardiovascular risk and in a limited life expectancy. It is well discussed that dysregulations related to Ca²⁺ signaling could link these diseases, in addition to cAMP signaling pathways. Thus, revealing this interplay among schizophrenia, diabetes, and asthma may provide novel insights into the pathogenesis of these diseases. Publications involving Ca²⁺ and cAMP signaling pathways, schizophrenia, diabetes, and asthma (alone or combined) were collected by searching PubMed and EMBASE. Both Ca²⁺ and cAMP signaling pathways (Ca²⁺/cAMP signaling) control the release of neurotransmitters and hormones, in addition to airway smooth muscle contractility, then dysregulations of these cellular processes may be involved in these diseases. Taking into consideration, the experience of our group in this field, this narrative review debated the involvement of Ca²⁺/cAMP signaling in this link among schizophrenia, diabetes, and asthma, including its pharmacological implications.

The genetics of asthma and the promise of genomics-guided drug target discovery

Asthma is an inflammatory airway disease that is estimated to affect 339 million people globally. The symptoms of about 5-10% of patients with asthma are not adequately controlled with current therapy, and little success has been achieved in developing drugs that target the underlying mechanisms of asthma rather than suppressing symptoms. Over the past 3 years, well powered genetic studies of asthma have increased the number of independent asthma-associated genetic loci to 128. In this Series paper, we describe the immense progress in asthma genetics over the past 13 years and link asthma genetic variants to possible drug targets. Further studies are needed to establish the functional significance of gene variants associated with asthma in subgroups of patients and to describe the biological networks within which they function. The genomics-guided discovery of plausible drug targets for asthma could pave the way for the repurposing of existing drugs for asthma and the development of new treatments.

The Infant Gut Microbiota and Risk of Asthma: The Effect of Maternal Nutrition during Pregnancy and Lactation

Research has amply demonstrated that early life dysbiosis of the gut microbiota influences the propensity to develop asthma. The influence of maternal nutrition on infant gut microbiota is therefore of growing interest. However, a handful of prospective studies have examined the role of maternal dietary patterns during pregnancy in influencing the infant gut microbiota but did not assess whether this resulted in an increased risk of asthma later in life. The mechanisms involved in the process are also, thus far, poorly documented. There have also been few studies examining the effect of maternal dietary nutrient intake during lactation on the milk microbiota, the effect on the infant gut microbiota and, furthermore, the consequences for asthma development remain largely unknown. Therefore, the specific aim of this mini review is summarizing the current knowledge regarding the effect of maternal nutrition during pregnancy and lactation on the infant gut microbiota composition, and whether it has implications for asthma development.

Exhaled Breath Condensate: A Non-Invasive Source for Tracking of Genetic and Epigenetic Alterations in Lung Diseases

Lung diseases have been recognized as an extensive cause of morbidity and mortality in the worldwide. The high degree of clinical heterogeneity and nonspecific initial symptoms of lung diseases contribute to a delayed diagnosis. So, the molecular and genomic profiling play a pivotal role in promoting the pulmonary diseases. Exhaled breath condensate (EBC) as a novel and potential method for sampling the respiratory epithelial lining fluid is to assess the inflammatory and oxidative stress biomarkers, drugs and genetic alterations in the pathophysiologic processes of lung diseases. The recent studies on the analysis of EBC from both a genetic and epigenetic point of view were searched from database and reviewed. This review provides an overview of the current findings in the tracking of genomic and epigenetic alterations which are potentially effective in better management of cancer detection. In addition, respiratory microbiota DNA using EBC samples in association with pulmonary disease especially lung cancer were investigated. Various studies have concluded that EBC has a great potential for analysis of nuclear and mitochondrial DNA alterations as well as epigenetic modifications and identification of respiratory microbiome. Next-generation sequencing (NGS) based genomic profiling of EBC samples is recommended as a promising approach to establish personalized based prevention, diagnosis, treatment and post-treatment follow-ups for patients with lung diseases especially lung cancer.

Novel Comprehensive Bioinformatics Approaches to Determine the Molecular Genetic Susceptibility Profile of Moderate and Severe Asthma

Background: Asthma is a chronic inflammatory condition linked to hyperresponsiveness in the airways. There is currently no cure available for asthma, and therapy choices are limited. Asthma is the result of the interplay between genes and the environment. The exact molecular genetic mechanism of asthma remains elusive. Aims: The aim of this study is to provide a comprehensive, detailed molecular etiology profile for the molecular factors that regulate the severity of asthma and pathogenicity using integrative bioinformatics tools. Methods: The GSE43696 omnibus gene expression dataset, which contains 50 moderate cases, 38 severe cases, and 20 healthy controls, was used to investigate differentially expressed genes (DEGs), susceptible chromosomal loci, gene networks, pathways, gene ontologies, and protein–protein interactions (PPIs) using an intensive bioinformatics pipeline. Results: The PPI network analysis yielded DEGs that contribute to interactions that differ from moderate-to-severe asthma. The combined interaction scores resulted in higher interactions for the genes STAT3, AGO2, COL1A1, CLCN6, and KSR for moderate asthma and JAK2, INSR, ERBB2, NR3C1, and PTK6 for severe asthma. Enrichment analysis (EA) demonstrated differential enrichment between moderate and severe asthma phenotypes; the ion transport regulation pathway was significantly enhanced in severe asthma phenotypes compared to that in moderate asthma phenotypes and involved PER2, GCR, IRS-2, KCNK7, KCNK6, NOX1, and SCN7A. The most enriched common pathway in both moderate and severe asthma is the development of the glucocorticoid receptor (GR) signaling pathway followed by glucocorticoid-mediated inhibition of proinflammatory and proconstrictory signaling in the airway of smooth muscle cell pathways. Gene sets were shared between severe and moderate asthma at 16 chromosome locations, including 17p13.1, 16p11.2, 17q21.31, 1p36, and 19q13.2, while 60 and 48 chromosomal locations were unique for both moderate and severe asthma, respectively. Phylogenetic analysis for DEGs showed that several genes have been intersected in phases of asthma in the same cluster of genes. This could indicate that several asthma-associated genes have a common ancestor and could be linked to the same biological function or gene family, implying the importance of these genes in the pathogenesis of asthma. Conclusion: New genetic risk factors for the development of moderate-to-severe asthma were identified in this study, and these could provide a better understanding of the molecular pathology of asthma and might provide a platform for the treatment of asthma.

Relevance of the first thousand days of life to the development of wheezing in children aged 6-7 years

INTRODUCTION

The first thousand days of life are a critical stage for the development of respiratory and immune systems. Many events in this period may be associated with wheezing in childhood.

OBJECTIVE

This study aimed to investigate the association between early life determinants and wheezing in children aged 6-7 years.

MATERIALS AND METHODS

Population-based case-control study using early-life related questions. We used the International Study of Asthma and Allergies in Childhood questionnaire to assess wheezing symptoms. Multiple logistic regressions were performed according to a hierarchical framework, considering the complex dynamic of wheezing/asthma and potential interaction between different levels of determination.

RESULTS

A total of 820 children were included, from which 162 reported wheezing symptoms (19.7%). Multivariable analysis identified socioeconomic conditions (OR 2.08, 95% CI 1.08-4.00), family history of asthma (OR 2.28, 95% CI 1.37-3.75), vaginal discharge that required treatment during pregnancy (OR 1.68, 95% CI 1.00-2.83), neonatal hyperbilirubinemia (OR 2.00, 95% CI 1.17-3.42), anemia and intestinal parasitosis in the first two years (OR 2.28, 95% CI 1.22-4.25; OR 1.72, 95% CI 1.02-2.92, respectively) independently associated to wheezing at 6-7 years. Intended pregnancy was associated with reduced wheezing (OR 0.47, 95% CI 0.28-0.77).

CONCLUSIONS

Several factors were associated with wheezing in childhood. Considering that intended pregnancy reduced wheezing and other associated exposures are considered modifiable, these findings may guide the planning of strategies to decrease the susceptibility to asthma symptoms in childhood.

Admixture mapping of asthma in southwestern Europeans with North African ancestry influences

The prevalence of asthma symptoms in Canary Islanders, a southwestern European population from Spain, is almost three times higher than the country average. Because the genetic risks identified so far explain <5% of asthma heritability, here we aimed to discover new asthma loci by completing the first admixture mapping study in Canary Islanders leveraging their distinctive genetic makeup, where significant northwest African influences coexist in the European genetic diversity landscape. A 2-stage study was conducted in 1,491 unrelated individuals self-declaring having a Canary Islands origin for the 4 grandparents. Local ancestry estimates were obtained for the shared positions with reference data from putative ancestral populations from Europe, North Africa, and sub-Saharan Africa. Case-control deviations in local ancestry were tested for each ancestry separately using logistic regressions adjusted for principal components, followed by fine-mapping analyses based on imputed genotypes and analyses of the likely deleterious exonic variants. The admixture mapping analysis of asthma detected that local North African ancestry in a locus spanning 365 kb of chromosome 16q23.3 was associated with asthma risk at study-wide significance [lowest P = 1.12 × 10^-4; odds ratio (OR) = 2.05; 95% confidence interval (CI) = 1.41-3.00]. Fine-mapping studies identified a variant associated with asthma, and results were replicated in independent samples (rs3852738, OR = 1.34; 95% CI = 1.13-1.59, P = 7.58 × 10^-4). Whole exome sequencing data from a subset of individuals revealed an enrichment of likely deleterious variants among asthma cases in 16q23.3, particularly in the phospholipase Cγ2 (PLCG2) gene (P = 3.67 × 10^-4). By completing the first mapping study of asthma in admixed populations from Europe, our results revealed a new plausible asthma locus.

Respiratory healthcare by design: Computational approaches bringing respiratory precision and personalised medicine closer to bedside

Precision medicine represents a potentially powerful means to alleviate the growing burden of chronic respiratory diseases. To realise its potential, however, we need a systems level understanding of how biological events (signalling pathways, cell-cell interactions, tissue mechanics) integrate across multiple spatial and temporal scales to give rise to pathology. This can be achieved most practically in silico: a paradigm that offers tight control over model parameters and rapid means of testing and generating mechanistic hypotheses. Patient-specific computational models that can enable identification of pathological mechanisms unique to patients' (omics, physiological, and anatomical) profiles and, therefore, personalised drug targets represent a major milestone in precision medicine. Current patient-based models in literature, especially medical devices, cardiac modelling, and respiratory medicine, rely mostly on (partial/ordinary) differential equations and have reached relatively advanced level of maturity. In respiratory medicine, patient-specific simulations mainly include subject scan-based lung mechanics models that can predict pulmonary function, but they treat the (sub)cellular processes as "black-boxes". A recent advance in simulating human airways at a cellular level to make clinical predictions raises the possibility of linking omics and cell level data/models with lung mechanics to understand respiratory pathology at a systems level. This is significant as this approach can be extended to understanding pathologies in other organs as well. Here, I will discuss ways in which computational models have already made contributions to personalised healthcare and how the paradigm can expedite clinical uptake of precision medicine strategies. I will mainly focus on an agent-based, asthmatic virtual patient that predicted the impact of multiple drug pharmacodynamics at the patient level, its potential to develop efficacious precision medicine strategies in respiratory medicine, and the regulatory and ethical challenges accompanying the mainstream application of such models.

Toxicogenomic analysis of publicly available transcriptomic data can predict food, drugs, and chemical-induced asthma

Background

: With the increasing incidence of asthma, more attention is focused on the diverse and complex nutritional and environmental triggers of asthma exacerbations. Currently, there are no established risk assessment tools to evaluate asthma triggering potentials of most of the nutritional and environmental triggers encountered by asthmatic patients.

Purpose

 The objective of this study is to devise a reliable workflow, capable of estimating the toxicogenomic effect of such factors on key player genes in asthma pathogenesis.

Methods

Gene expression extracted from publicly available datasets of asthmatic bronchial epithelium were subjected to a comprehensive analysis of differential gene expression to identify significant genes involved in asthma development and progression. The identified genes were subjected to Gene Set Enrichment Analysis using a total of 31,826 gene sets related to chemical, toxins, and drugs to identify common agents that share similar asthma-related targets genes and signaling pathways.

Results

Our analysis identified 225 differentially expressed genes between severe asthmatic and healthy bronchial epithelium. Gene Set Enrichment Analysis of the identified genes showed that they are involved in response to toxic substances and organic cyclic compounds and are targeted by 41 specific diets, plants products, and plants related toxins (eg adenine, arachidonic acid, baicalein, caffeic acid, corilagin, curcumin, ellagic acid, luteolin, microcystin-RR, phytoestrogens, protoporphyrin IX, purpurogallin, rottlerin, and salazinic acid). Moreover, the identified chemicals share interesting inflammation-related pathways like NF-κB.

Conclusion

Our analysis was able to explain and predict the toxicity in terms of stimulating the differentially expressed genes between severe asthmatic and healthy epithelium. Such an approach can pave the way to generate a cost-effective and reliable source for asthma-specific toxigenic reports thus allowing the asthmatic patients, physicians, and medical researchers to be aware of the potential triggering factors with fatal consequences.

Influences of Maternal Factors Over Offspring Allergies and the Application for Food Allergy

The prevalence of food allergy has been steadily rising worldwide with the highest incidence noted among younger children, and increasingly recognized as a growing public concern. The first known ingestion of foods often causes allergic reaction, suggesting that sensitization of offspring with food allergens may occur during pregnancy and/or through breastfeeding. This creates a milieu that shapes the neonatal immune responses to these allergens. However, the effects of maternal allergen exposure and maternal sensitization with allergens on development of allergies in offspring remain controversial. This review discusses recent advances from human data in our understanding of how maternal factors, namely, food allergens, allergen-specific immunoglobulins, cytokines, genetics, and environmental factors transferred during pregnancy or breastfeeding influence offspring allergies and how such effects may be applicable to food allergy. Based on information obtained from mouse models of asthma and food allergy, the review also dissects the mechanisms by which maternal factors, including the impact of immune complexes, transforming growth factor-β, vitamin A, and regulatory T-cell responses, contribute to the induction of neonatal tolerance vs. development of allergic responses to maternally transferred allergens.

Determination of Personalized Asthma Triggers From Multimodal Sensing and a Mobile App: Observational Study

BACKGROUND

Asthma is a chronic pulmonary disease with multiple triggers. It can be managed by strict adherence to an asthma care plan and by avoiding these triggers. Clinicians cannot continuously monitor their patients' environment and their adherence to an asthma care plan, which poses a significant challenge for asthma management.

OBJECTIVE

In this study, pediatric patients were continuously monitored using low-cost sensors to collect asthma-relevant information. The objective of this study was to assess whether kHealth kit, which contains low-cost sensors, can identify personalized triggers and provide actionable insights to clinicians for the development of a tailored asthma care plan.

METHODS

The kHealth asthma kit was developed to continuously track the symptoms of asthma in pediatric patients and monitor the patients' environment and adherence to their care plan for either 1 or 3 months. The kit consists of an Android app-based questionnaire to collect information on asthma symptoms and medication intake, Fitbit to track sleep and activity, the Peak Flow meter to monitor lung functions, and Foobot to monitor indoor air quality. The data on the patient's outdoor environment were collected using third-party Web services based on the patient's zip code. To date, 107 patients consented to participate in the study and were recruited from the Dayton Children's Hospital, of which 83 patients completed the study as instructed.

RESULTS

Patient-generated health data from the 83 patients who completed the study were included in the cohort-level analysis. Of the 19% (16/83) of patients deployed in spring, the symptoms of 63% (10/16) and 19% (3/16) of patients suggested pollen and particulate matter (PM2.5), respectively, to be their major asthma triggers. Of the 17% (14/83) of patients deployed in fall, symptoms of 29% (4/17) and 21% (3/17) of patients suggested pollen and PM2.5, respectively, to be their major triggers. Among the 28% (23/83) of patients deployed in winter, PM2.5 was identified as the major trigger for 83% (19/23) of patients. Similar correlations were not observed between asthma symptoms and factors such as ozone level, temperature, and humidity. Furthermore, 1 patient from each season was chosen to explain, in detail, his or her personalized triggers by observing temporal associations between triggers and asthma symptoms gathered using the kHealth asthma kit.

CONCLUSIONS

The continuous monitoring of pediatric asthma patients using the kHealth asthma kit generates insights on the relationship between their asthma symptoms and triggers across different seasons. This can ultimately inform personalized asthma management and intervention plans.

kBot: Knowledge-enabled Personalized Chatbot for Asthma Self-Management

There is a well-recognized need for a shift to proactive asthma care given the impact asthma has on overall healthcare costs. The demand for continuous monitoring of patient's adherence to the medication care plan, assessment of environmental triggers, and management of asthma can be challenging in traditional clinical settings and taxing on clinical professionals. Recent years have seen a robust growth of general purpose conversational systems. However, they lack the capabilities to support applications such an individual's health, which requires the ability to contextualize, learn interactively, and provide the proper hyper-personalization needed to hold meaningful conversations. In this paper, we present kBot, a knowledge-enabled personalized chatbot system designed for health applications and adapted to help pediatric asthmatic patients (age 8 to 15) to better control their asthma. Its core functionalities include continuous monitoring of the patient's medication adherence and tracking of relevant health signals and environment data. kBot takes the form of an Android application with a frontend chat interface capable of conversing in both text and voice, and a backend cloud-based server application that handles data collection, processing, and dialogue management. It achieves contextualization by piecing together domain knowledge from online sources and inputs from our clinical partners. The personalization aspect is derived from patient answering questionnaires and day-to-day conversations. kBOT's preliminary evaluation focused on chatbot quality, technology acceptance, and system usability involved eight asthma clinicians and eight researchers. For both groups, kBot achieved an overall technology acceptance value of greater than 8 on the 11-point Likert scale and a mean System Usability Score (SUS) greater than 80.