Sex Bias in Asthma Prevalence and Pathogenesis

Masculinising testosterone treatment and effects on preclinical cardiovascular disease, muscle strength and power, aggression, physical fitness and respiratory function in transgender men: protocol for a 10-year, prospective, observational cohort study in Denmark at the Body Identity Clinic (BIC)

INTRODUCTION

The number of individuals with gender dysphoria seeking gender-affirming treatment is increasing. The short-term and long-term effects of masculinising treatment with testosterone are debated as serum testosterone increases up to 20-fold compared with cisgender women. We will investigate short-term and long-term effects of masculinising testosterone treatment on preclinical and clinical coronary disease, muscle strength and power, oxygen consumption (VO₂) max, cardiac and respiratory function and quality of life including aggression in transgender men.

METHODS AND ANALYSES

Prospective, single-centre, observational cohort study at the Body Identity Clinic (BIC), Odense University Hospital, Denmark. Investigations are performed at inclusion and following 1, 3, 5 and 10 years of testosterone therapy. Non-calcified coronary plaque volume and calcium score are estimated by coronary CT angiography. CT is only performed at inclusion and following 1 and 10 years. Upper body muscle strength and power are measured by a 'low row' weight stack resisted exercise machine. Evaluation of aggression and quality of life is assessed by questionnaires, VO₂ max is estimated by maximal testing on bike ergometer, and cardiac and respiratory functions are measured by echocardiography and spirometry, respectively. Markers of cardiovascular risk and inflammation and also cortisol and cortisone are assessed in blood, diurnal urine and/or hair samples. Our cohort (BIC), including dropouts, will be an embedded subcohort in a future national registry study in all individuals with gender dysphoria and controls. Data are available on International Statistical Classification of Diseases and Related Health Problems 10^th version diagnostic codes, prescriptions, socioeconomics and causes of death.

ETHICS AND DISSEMINATION

The Regional Committee on Health Research Ethics for Southern Denmark (S-20190108) and the Danish Data Protection Agency (19/27572) approved the study. Signed informed consent will be obtained from all participants. All findings will be published in peer-reviewed journals or at scientific conferences.

TRIAL REGISTRATION NUMBER

NCT04254354.

Factors Contributing to Sex Differences in Mice Inhaling Aspergillus fumigatus

Aspergillus fumigatus is a respiratory fungal pathogen and an allergen, commonly detected in flooded indoor environments and agricultural settings. Previous studies in Balb/c mice showed that repeated inhalation of live and dry A. fumigatus spores, without any adjuvant, elevated allergic immune response and airway remodeling. Sex-specific differences can influence host-pathogen interactions and allergic-asthma related outcomes. However, the effect of host sex on immune response, in the context of A. fumigatus exposure, remains unknown. In this study, we quantified the multivariate and univariate immune response of C57BL/6J mice to live, dry airborne A. fumigatus spores. Our results corroborate previous results in Balb/c mice that repeated inhalation of live A. fumigatus spores is sufficient to induce mucus production and inflammation by day 3 post last challenge, and antibody titers and collagen production by day 28 post-challenge. Principal Component Analysis (PCA) showed that females exhibited significantly higher levels of immune components than males did. Taken together, our data indicate that host-sex is an important factor in shaping the immune response against A. fumigatus, and must be considered when modeling disease in animals, in designing diagnostics and therapeutics for A. fumigatus-associated diseases or while drafting evidence-based guidelines for safe mold levels.

The Role of Neutrophils in the Pathophysiology of Asthma in Humans and Horses

Asthma is a common and debilitating chronic airway disease that affects people and horses of all ages worldwide. While asthma in humans most commonly involves an excessive type 2 immune response and eosinophilic inflammation, neutrophils have also been recognized as key players in the pathophysiology of asthma, including in the severe asthma phenotype where neutrophilic inflammation predominates. Severe equine asthma syndrome (sEAS) features prominent neutrophilic inflammation and has been increasingly used as a naturally occurring animal model for the study of human neutrophilic asthma. This comparative review examines the recent literature in order to explore the role of neutrophil inflammatory functions in the pathophysiology and immunology of asthma in humans and horses.

Sex-specific effects of in utero and adult tobacco smoke exposure

Tobacco smoke has harmful effects on a multiorgan level. Exposure to smoke, whether in utero or environmental, significantly increases susceptibility. This susceptibility has been identified to be divergent between males and females. However, there remains a distinct lack of thorough research into the relationship between sex and exposure to tobacco. Females tend to generate a more significant response than males during adulthood exposure. The intrauterine environment is meticulously controlled, and exposure to tobacco presents a significant factor that contributes to poor health outcomes and susceptibility later in life. Analysis of these effects in relation to the sex of the offspring is yet to be holistically reviewed and summarized. In this review, we will delineate the time-dependent relationship between tobacco smoke exposure and sex-specific disease susceptibility. We further outline possible biological mechanisms that may contribute to the identified pattern.

Sex Differences in Exercise-Induced Bronchoconstriction in Athletes: A Systematic Review and Meta-Analysis

Exercise-induced bronchoconstriction (EIB) is a common complication of athletes and individuals who exercise regularly. It is estimated that about 90% of patients with underlying asthma (a sexually dimorphic disease) experience EIB; however, sex differences in EIB have not been studied extensively. With the goal of better understanding the prevalence of EIB in males and females, and because atopy has been reported to occur at higher rates in athletes, in this study, we investigated sex differences in EIB and atopy in athletes. A systematic literature review identified 60 studies evaluating EIB and/or atopy in post-pubertal adult athletes (n = 7501). Collectively, these studies reported: (1) a 23% prevalence of EIB in athletes; (2) a higher prevalence of atopy in male vs. female athletes; (3) a higher prevalence of atopy in athletes with EIB; (4) a significantly higher rate of atopic EIB in male vs. female athletes. Our analysis indicates that the physiological changes that occur during exercise may differentially affect male and female athletes, and suggest an interaction between male sex, exercise, and atopic status in the course of EIB. Understanding these sex differences is important to provide personalized management plans to athletes with underlying asthma and/or atopy.

Susceptibility Factors in Chronic Lung Inflammatory Responses to Engineered Nanomaterials

Engineered nanomaterials (ENMs) are products of the emerging nanotechnology industry and many different types of ENMs have been shown to cause chronic inflammation in the lungs of rodents after inhalation exposure, suggesting a risk to human health. Due to the increasing demand and use of ENMs in a variety of products, a careful evaluation of the risks to human health is urgently needed. An assessment of the immunotoxicity of ENMs should consider susceptibility factors including sex, pre-existing diseases, deficiency of specific genes encoding proteins involved in the innate or adaptive immune response, and co-exposures to other chemicals. This review will address evidence from experimental animal models that highlights some important issues of susceptibility to chronic lung inflammation and systemic immune dysfunction after pulmonary exposure to ENMs.

Sex effects in the association between airway microbiome and asthma

BACKGROUND

Sex differences exist in asthma susceptibility and severity. Accumulating evidence has linked airway microbiome dysbiosis to asthma, and airway microbial communities have been found to differ by sex. However, whether sex modifies the link between airway microbiome and asthma has not been investigated.

OBJECTIVE

To evaluate sex effects in the association between airway microbiome and asthma.

METHODS

We analyzed induced sputum samples from 47 subjects (n = 23 patients with asthma and n = 24 normal controls) using 16S ribosomal RNA gene sequencing methods. The bacterial composition was analyzed for sex differences. Bacterial associations with asthma were assessed for each sex at the core taxa and genus levels.

RESULTS

The microbiome in induced sputum differed in women vs men at the community level. A total of 5 core bacterial taxa were found in all samples. No sex-specific core taxa were detected. The most abundant core taxon, Streptococcus salivarius, was significantly enriched in women than in men (P = .02). Within each sex, individuals with relatively lower abundance of S salivarius were more likely to have asthma (P = .006). For both sexes, increased Lactobacillus species were found in sputum samples of patients with patients compared with normal controls (adjusted P = .01). Haemophilus species were associated with asthma in men and not in women.

CONCLUSION

The airway microbiome differed by sex, and sex effects exist in the association of airway microbial markers and asthma. Future airway microbiome studies may yield better resolution if the context of specific sex is considered. The airway microbiome is a potential mechanism driving sex differences in asthma.

Serum free testosterone and asthma, asthma hospitalisations and lung function in British adults

OBJECTIVE

We examined the relation between serum-free testosterone and asthma, wheeze, asthma hospitalisations and lung function in older adults.

DESIGN

Cross-sectional study.

SETTING

UK.

PARTICIPANTS

256 419 adults aged 40 to 69 years, recruited from 2006 to 2010.

MAIN OUTCOME MEASURES

Multivariable logistic or linear regression was used for the analysis of free testosterone and physician-diagnosed asthma, current wheeze, asthma hospitalisations and lung function measures, which was adjusted for serum estradiol, smoking status and other covariates.

RESULTS

Free testosterone levels above the lowest quartile (Q1) were significantly associated with lower odds of asthma in both women (adjusted OR (aOR) for Q4 (the highest quartile) versus Q1=0.67, 95% CI=0.64 to 0.71) and men (aOR for Q4 versus Q1=0.87, 95% CI=0.82 to 0.91). Among subjects with asthma, free testosterone levels above Q1 were significantly associated with lower odds of current wheeze in women (aOR range=0.78 to 0.87), and free testosterone levels in Q4 were associated with lower odds of current wheeze in men (aOR for Q4 versus Q1=0.86, 95% CI=0.77 to 0.95). Among women with asthma, free testosterone levels in Q4 were also associated with lower odds of ≥1 asthma hospitalisation. Among men, free testosterone was positively associated with FEV₁ and FVC. Among women, free testosterone was negatively and weakly associated with FVC.

CONCLUSION

In a large study of British adults, elevated free testosterone levels are associated with lower odds of asthma and current wheeze in women and men, lower odds of asthma hospitalisations in women, and higher FEV₁ and FVC in men. DISSEMINATION TO PARTICIPANTS, AND RELATED PATIENT AND PUBLIC COMMUNITIES: The results of the study will be linked to the UK Biobank website.

Sex and gender: modifiers of health, disease, and medicine

Clinicians can encounter sex and gender disparities in diagnostic and therapeutic responses. These disparities are noted in epidemiology, pathophysiology, clinical manifestations, disease progression, and response to treatment. This Review discusses the fundamental influences of sex and gender as modifiers of the major causes of death and morbidity. We articulate how the genetic, epigenetic, and hormonal influences of biological sex influence physiology and disease, and how the social constructs of gender affect the behaviour of the community, clinicians, and patients in the health-care system and interact with pathobiology. We aim to guide clinicians and researchers to consider sex and gender in their approach to diagnosis, prevention, and treatment of diseases as a necessary and fundamental step towards precision medicine, which will benefit men's and women's health.

Prevalence and determinants of current asthma in Cameroon

INTRODUCTION

The prevalence of asthma varies from one country to another due to differences in ethnicity, socio-economics status, environmental and climatic risk factors. The aim of this study was to determine the prevalence and determinants of current asthma in Cameroonian adults.

MATERIAL AND METHODS

Data from 4 cross-sectional community-based studies from 2014 to 2018 were analyzed. Participants aged 19 years and above were selected through multilevel stratified random sampling methods across 2 urban areas, 2 semi-urban areas and 1 rural area. Current asthma was defined as "wheezing in the last 12 months in a subject with self-reported asthma or having used drugs for asthma treatment". Logistic regression was used to investigate the determinants of current asthma.

RESULTS

A total of 10,707 adults [median age (interquartile range)=36 (26-52) years, 44.5% of men] were definitively enrolled in the study. The overall prevalence [95% confidence interval (CI)] of current asthma was 3.9% (3.5-4.3)%. Determinants [odd's ratio (OR), (95%CI)] of current asthma were: Sudanese ethnicity [1.9(1.4-2.7)], rural area [1.5(1.1-2.1)], urban area [1.6(1.2-2.2)], past history of pneumonia [1.9(1.1-3.4)], allergic rhino-conjunctivitis [6.5(4.7-8.9)], atopic eczema [2.3(1.5-3.6)], body mass index (BMI)≥40kg/m² [1.9(1.0-3.4)] and BMI<18kg/m² [1.8(1.2-2.9)].

CONCLUSION

The prevalence of current asthma is close to the low value of the Sub-Saharan African range. Sudanese ethnicity, rural area, urban area, history of pneumonia, allergic disease, severe obesity and underweight were determinants of current asthma in Cameroon. More research is surely warranted to understand the mechanisms underlying the association of asthma with Sudanese ethnicity.

The course of asthma: A population-based 10-year study examining asthma remission in children diagnosed with asthma in preschool

BACKGROUND

The natural course of asthma may differ depending on the age of onset.

OBJECTIVE

To investigate predictors of asthma remission with a focus on the age of asthma onset.

METHODS

The study was a retrospective birth cohort of children with asthma in Saskatchewan, Canada. Using the Saskatchewan Ministry of Health databases, we identified children with a diagnosis of asthma in the first 6 years of life and who had at least 10 years of follow-up after diagnosis (n = 22 563). Of these, we included 6393 children either with persistent asthma (≥1 physician visit or hospitalization for asthma [PVHA] during each year of follow-up) and those who had remission (had PVHA in the first year after diagnosis but at some point during the follow-up no longer received PVHA until end of the study). We used survival analysis to examine associations between remission and age of asthma onset.

RESULTS

Of the study participants, 87.2% had early-onset (≤3 years) and 12.8% had late-onset (4-6 years) asthma. Over the 10-years of follow-up, the rate of asthma remission was 37 per 100 person-years. Early-onset asthma (hazard ratio [HR] = 1.10; 95%confidence interval [CI]: 1.01-1.20), being female (HR = 1.12; 95%CI: 1.07-1.18), living in a rural (HR = 1.20; 95%CI: 1.14-1.27) and medium urban (HR = 1.16; 95%CI: 1.08-1.26) location were positively associated with remission while history of atopy decreased likelihood of remission (HR = 0.73; 95%CI: 0.54-0.97).

CONCLUSION

Most children with asthma experienced remission, especially those with the onset of symptoms within the first 3 years of life.

Determinants of Allergic Sensitization, Asthma and Lung Function: Results from a Cross-Sectional Study in Italian Schoolchildren

Prenatal smoking exposure and early-life respiratory infections are major determinants of asthma during childhood. We investigate the factors influencing allergic sensitization (AS), asthma, and lung function in children and the balance between individual and environmental characteristics at different life stages. 1714 children aged 7–16 years and living in southern Italy were investigated using a parental questionnaire, skin prick tests, and spirometry. We found 41.0% AS prevalence: among children without parental history of asthma, male sex, maternal smoking during pregnancy (MatSmoke), and acute respiratory diseases in the first two years of life (ARD2Y) were significant risk factors for AS. MatSmoke was associated (OR = 1.79) with ARD2Y, and this association was influenced by sex. ARD2Y was, in turn, a significant risk factor (OR = 8.53) for childhood current asthma, along with AS (OR up to 3.03) and rhinoconjuctivitis (OR = 3.59). Forced mid-expiratory flow (FEF_25–75%) was negatively affected by ARD2Y, with a sex-related effect. Thus, males exposed to MatSmoke had significantly lower FEF_25–75% than unexposed males. Despite the difficulty of discriminating among the complex interactions underlying the development of allergic respiratory diseases, ARD2Y appears to strongly influence both asthma and lung function during childhood. In turn, ARD2Y is influenced by prenatal exposure to tobacco smoke with a sex-dependent effect.

Risk of Prevalent Asthma among Children Affected by Inflammatory Bowel Disease: A Population-Based Birth Cohort Study

Literature on the risk of asthma among children with inflammatory bowel disease (IBD) is limited and has reported discording results. To the best of our knowledge, no previous study has evaluated the association between asthma and childhood onset IBD, focusing on pediatric IBD with onset between 10 and 17 years, early-onset IBD (EO-IBD) between 0 and 9 years, and very early-onset IBD (VEO-IBD) between 0 and 5 years, all conditions characterized by different clinical progressions. A nested matched case-control design on a longitudinal cohort of 213,515 newborns was adopted. Conditional binomial regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) of asthma among children with IBD compared with controls. We found 162 children with IBD and 1620 controls. Overall, childhood onset IBD was associated with increased risks of being affected by asthma (OR: 1.49 95% CI 1.05–2.12), although a significant risk was only present among males (OR: 1.60 95% CI 1.02–2.51). Children with Crohn’s disease and ulcerative colitis had similarly increased risks, although they failed to attain statistical significance. Risks of asthma based on age at IBD onset were inversely related to age, with the lowest non-significant risks for pediatric IBD and EO-IBD, while children affected by VEO-IBD had the highest risk of asthma (OR: 2.75 95% CI 1.26–6.02). Our study suggests the presence of a higher prevalence of asthma among both male children with IBD and children with VEO-IBD. It could be advisable to pay greater attention to possible respiratory symptoms among these categories at higher risk.

Circular RNA circHIPK3 modulates the proliferation of airway smooth muscle cells by miR-326/STIM1 axis

AIMS

Emerging findings demonstrate the critical roles of noncoding RNA (ncRNA) in asthma development. Nevertheless, the biological roles of circular RNA (circRNA) in airway remodeling are still elusive. Here, the present research focuses on the regulation of circRNA circHIPK3 in airway smooth muscle cells (ASMCs) proliferation and migration.

MATERIALS AND METHODS

The sequence of circRNA was detected using Sanger sequencing. Cellular phenotypes were detected using CCK-8 assay, transwell and flow cytometer assay. The potential binding of miRNA and downstream and upstream targets was detected using dual-luciferase reporter assay.

KEY FINDINGS

Results showed that circHIPK3 was significantly upregulated in platelet-derived growth factor (PDGF) induced ASMCs. Functional analysis using CCK-8, transwell migration assays and flow cytometry analysis showed that circHIPK3 knockdown repressed proliferation, migration and up-regulated the apoptosis in ASMCs. Mechanistic assays showed that circHIPK3 sponged miR-326 in the cytoplasm, thereby targeting stromal interaction molecule 1 (STIM1) to regulate ASMCs' proliferation, migration and apoptosis.

SIGNIFICANCE

Collectively, the data elucidates that circHIPK3 functions as a regulator in the airway remodeling during the asthma development through miR-326/STIM1 axis, providing a novel insight for the therapeutic target.

Maternal stress in relation to sex-specific expression of placental genes involved in nutrient transport, oxygen tension, immune response, and the glucocorticoid barrier

INTRODUCTION

Murine models provide evidence that maternal stress during pregnancy can influence placenta morphology and function, including altered expression of genes involved in the maintenance and progression of pregnancy and fetal development. Corresponding research evaluating the impact of maternal stress on placental gene expression in humans is limited. We examined maternal stress in relation to placental expression of 17 candidate genes in a community-based sample.

METHODS

Participants included 60 mother-newborn pairs enrolled in the PRogramming of Intergenerational Stress Mechanisms pregnancy cohort based at the Mount Sinai Hospital in New York City. Placentas were collected immediately following delivery and gene expression was measured using a qPCR-based platform. Maternal experiences of traumatic and non-traumatic stress were measured using the Life Stressor Checklist-Revised (LSC-R) administered during a mid-pregnancy interview. We used multivariable linear regression to examine associations between LSC-R scores and expression of each gene in separate models in the sample overall and stratified by fetal sex.

RESULTS

Higher maternal stress was associated with significantly increased placental expression of the nutrient sensor gene OGT, the glucose transporter gene GLUT1, and the hypoxia sensor gene HIF3A. In models stratified by fetal sex, significant associations remained only among males.

DISCUSSION

This study represents one of the most comprehensive examinations of maternal lifetime traumatic and non-traumatic stress in relation to placental gene expression in human tissue. Our findings support that maternal stress may alter sex-specific placental expression of genes involved in critical developmental processes.

Asthma, Chronic Obstructive Pulmonary Disease, and Subsequent Risk for Incident Rheumatoid Arthritis Among Women: A Prospective Cohort Study

OBJECTIVE

Inflamed airways are hypothesized to contribute to rheumatoid arthritis (RA) pathogenesis due to RA-related autoantibody production, and smoking is the strongest environmental RA risk factor. However, the role of chronic airway diseases in RA development is unclear. We undertook this study to investigate whether asthma and chronic obstructive pulmonary disease (COPD) were each associated with RA.

METHODS

We performed a prospective cohort study of 205,153 women in the Nurses' Health Study (NHS, 1988-2014) and NHSII (1991-2015). Exposures were self-reported physician-diagnosed asthma or COPD confirmed by validated supplemental questionnaires. The primary outcome was incident RA confirmed by medical record review by 2 rheumatologists. Covariates (including smoking pack-years/status) were assessed via biennial questionnaires. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for RA were estimated using Cox regression.

RESULTS

We identified 15,148 women with confirmed asthma, 3,573 women with confirmed COPD, and 1,060 incident RA cases during 4,384,471 person-years (median 24.0 years/participant) of follow-up in the NHS and NHSII. Asthma was associated with increased RA risk (HR 1.53 [95% CI 1.24-1.88]) compared to no asthma/COPD after adjustment for covariates, including smoking pack-years/status. Asthma remained associated with increased RA risk when analyzing only never-smokers (HR 1.53 [95% CI 1.14-2.05]). COPD was also associated with increased RA risk (HR 1.89 [95% CI 1.31-2.75]). The association of COPD with RA was most pronounced in the subgroup of ever-smokers age >55 years (HR 2.20 [95% CI 1.38-3.51]).

CONCLUSION

Asthma and COPD were each associated with increased risk of incident RA, independent of smoking status/intensity and other potential confounders. These results provide support for the hypothesis that chronic airway inflammation may be crucial in RA pathogenesis.

The disease burden of childhood asthma in China: a systematic review and meta-analysis

Background

In China, childhood asthma prevalence showed a remarkable increase in the past decades. An updated epidemiological assessment of childhood asthma in China with a focus on prevalence and time trends is required.

Methods

We systematically searched three main Chinese databases and one English database to identify epidemiological studies of the prevalence of childhood asthma in China. Asthma cases were defined according to one of the five sets of Chinese diagnostic criteria which were established by the Children Respiratory Disease Group. We estimated age- and sex-specific prevalence of asthma using a multilevel mixed-effects logistic regression. We presented the time trends of asthma prevalence between 1990 and 2020 by age, sex and setting (urban vs rural), and also estimated the number of children affected by asthma in 2010.

Results

In 1990, the prevalence of asthma ranged from 0.13% (95% confidence interval (CI) = 0.10-0.20) in rural girls aged 14 years to 1.34% (95% CI = 1.11-1.67) in urban boys aged five years. In 2010, the overall prevalence of asthma in Chinese children aged 0-14 years was 2.12% (95% CI = 1.83-2.51), corresponding to 5.16 million children living with asthma. Children aged 5-9 years were with the highest prevalence estimate of 2.65% (95% CI = 2.31-3.12) and those aged 10-14 years were with the lowest (1.48%, 95% CI = 1.26-1.78). In 2020, it is expected that this disparity will continue, with the prevalence of asthma being at the lowest level among rural girls aged 14 years (1.11%, 95% CI = 0.82-1.54) and at the highest level among urban boys aged four years (10.27%, 95% CI = 8.61-12.18). Over the 30 years (1990-2020), the prevalence of asthma in children aged 0-14 years has increased in both sexes and settings, which was consistently the lowest in rural girls and the highest in urban boys.

Conclusions

This study shows that childhood asthma has been increasingly prevalent in China. Asthma is more frequent in boys and in rural areas. The detailed and systematic estimates of asthma prevalence in this study constitute the best currently available basis for policymaking, planning, and allocation of health and welfare resources related to the burden of childhood asthma in China.

Sex and Gender Aspects for Patient Stratification in Allergy Prevention and Treatment

Allergies are rapidly worsening in recent decades, representing the most common immunological diseases. The mechanism of disorders such as asthma, rhinocongiuntivitis, urticaria, atopic dermatitis, food and drug allergies, and anaphylaxis still remain unclear and consequently treatments is mostly still symptomatic and aspecific while developments of new therapies are limited. A growing amount of data in the literature shows us how the prevalence of allergic diseases is different in both sexes and its changes over the course of life. Genes, hormones, environmental and immunological factors affect sex disparities associated with the development and control of allergic diseases, while they more rarely are considered and reported regarding their differences related to social, psychological, cultural, economic, and employment aspects. This review describes the available knowledge on the role of sex and gender in allergies in an attempt to improve the indispensable gender perspective whose potential is still underestimated while it represents a significant turning point in research and the clinic. It will offer insights to stimulate exploration of the many aspects still unknown in this relationship that could ameliorate the preventive, diagnostic, and therapeutic strategies in allergic diseases.

Sex Steroid Hormones and Asthma in a Nationwide Study of U.S. Adults

Rationale: Women have a higher burden of asthma than men. Although sex hormones may explain sex differences in asthma, their role is unclear.Objectives: To examine sex hormone levels and asthma in adults.Methods: Cross-sectional study of serum levels of free testosterone and estradiol and current asthma in 7,615 adults (3,953 men and 3,662 women) aged 18-79 years who participated in the 2013-2014 and 2015-2016 U.S. National Health and Nutrition Examination Survey. Logistic regression was used for the multivariable analysis of sex hormones and current asthma, which was conducted separately in women and men.Measurements and Main Results: Free testosterone levels in the fourth quartile were associated with lower odds of current asthma in women (odds ratio [OR] for the fourth quartile [Q4] vs. Q1, 0.56; 95% confidence interval [CI], 0.39-0.80). Given an interaction between obesity and sex hormones on current asthma, we stratified the analysis by obesity. In this analysis, elevated free testosterone (OR for Q4 vs. Q1, 0.59; 95% CI, 0.37-0.91) and estradiol (OR for Q4 vs. Q1, 0.43; 95% CI, 0.23-0.78) levels were associated with reduced odds of current asthma in obese women, and an elevated serum estradiol was associated with lower odds of current asthma in nonobese men (OR for Q4 vs. Q1, 0.44; 95% CI, 0.21-0.90).Conclusions: Our findings suggest that sex hormones play a role in known sex differences in asthma in adults. Moreover, our results suggest that obesity modifies the effects of sex hormones on asthma in adults.

Proteomic analysis of sex differences in hyperoxic lung injury in neonatal mice

Sex-specific differences in the severity of bronchopulmonary dysplasia (BPD) are due to different susceptibility to hyperoxic lung injury, but the mechanism is unclear. In this study, neonatal male and female mouse pups (C57BL/6J) were exposed to hyperoxia and lung tissues were excised on postnatal day 7 for histological analysis and tandem mass tags proteomic analysis. We found that the lung sections from the male mice following postnatal hyperoxia exposure had increased alveolar simplification, significant aberrant pulmonary vascularization and arrest in angiogenesis compared with females. Comparison of differentially expressed proteins revealed 377 proteins unique to female and 425 unique to male as well as 750 proteins in both male and female. Bioinformatics analysis suggested that several differentially expressed proteins could contribute to the differences in sex-specific susceptibility to hyperoxic lung injury. Our results may help identify sex-specific biomarkers and therapeutic targets of BPD.

Oestrogen amplifies pre-existing atopy-associated Th2 bias in an experimental asthma model

BACKGROUND

The prevalence and severity of asthma, particularly the most common (atopic) form of the disease, increase amongst females but not males after puberty, and asthma activity also changes throughout the menstrual cycle and during pregnancy. The contribution of female sex hormones to asthma pathogenesis is incompletely understood.

OBJECTIVE

To obtain insight into the role of oestrogen (E2) in experimental atopic asthma, and guide future research on sex-related variations in atopic asthma susceptibility/intensity in humans.

METHODS

We utilized an experimental model comprising rat strains expressing dichotomous Th2-high vs Th2-low immunophenotypes exemplified by eosinophilia, mirroring differences between human atopics/non-atopics. We compared the efficiency of Th2-associated immunoinflammatory mechanisms, which differed markedly between the two strains, and between sexes in the Th2-high strain, and determined the effects of E2 administration on these differences.

RESULTS

Unique to the Th2-high strain, eosinophil: neutrophil ratios in the airways at baseline and following sensitization/aeroallergen challenge were logfold higher in females relative to males, and this was reflected by higher baseline blood eosinophil numbers in females. Pretreatment of Th2-high males with E2 abrogated this sex difference by selectively boosting Th2-associated genes in the airways and eosinophilia, but was without corresponding effect in the Th2-low strain. In contrast, parallel E2 effects on myeloid and lymphoid cell populations were relatively modest.

CONCLUSIONS AND CLINICAL RELEVANCE

E2 acts to amplify the eosinophilic component of pre-existing Th2-high immunophenotype, possibly acting at the level of the common eosinophil/neutrophil precursor in bone marrow to preferentially drive eosinophil differentiation. Constitutive granulocyte profiles in which the balance between eosinophils and neutrophils is skewed towards eosinophils have been identified in independent cohort studies as markers of asthma risk, and these findings suggest that more detailed studies on the role of E2 in this context, and in relation to asthma pathogenesis in post-pubertal females in particular, appear warranted.

Sex differences in the influence of obesity on a murine model of allergic lung inflammation

BACKGROUND

Despite the overwhelming evidence showing the influence of sex or obesity in the development of respiratory diseases in humans and animals, the mechanisms by which these combined two factors influence allergic asthma are not well understood.

OBJECTIVE

We have investigated the interaction between sex and weight gain in an experimental model of lung allergic inflammation induced by chicken egg ovalbumin (OVA) in mice.

METHODS

Animals were fed a high-fat diet for 8 weeks and then sensitized and challenged with OVA.

RESULTS

Our results demonstrate that in comparison with males, high-fat diet (HFD) allergic female mice exhibit a reduction in the number of leucocytes in the lung lumen when challenged with OVA and, in contrast, an accumulation of these cells in the lung tissue. In addition, we also observed that allergic HFD female mice presented a robust lung remodelling in comparison with HFD males, evidenced by higher deposition of collagen in the airways and TGF-β in lung fluid. Measuring epithelial adhesion molecule expression, we observed that female mice presented a significantly lower expression of CD103 than males in BAL cells, regardless of the diet. Similarly, HFD female mice express lower levels of EpCAM in lung tissue in comparison with males and lean females. Levels of A20/TNFAIP3 expression in lung tissue demonstrated that HFD female mice express lower levels of these regulatory factors than all the other groups. However, this reduction was not accompanied by an increase in activated NF-κB.

CONCLUSIONS

Our results present evidence that the interaction between sex and weight gain alters the progression of allergic asthma in mice with females developing airway remodelling at a much earlier stage than males.

CLINICAL RELEVANCE

These data may contribute to a better understanding of the clinical differences in the development and severity of allergic asthma observed between men and women of reproductive age.

ERα Signaling Increased IL-17A Production in Th17 Cells by Upregulating IL-23R Expression, Mitochondrial Respiration, and Proliferation

Women have increased prevalence of Th17-mediated autoimmune diseases, including lupus and multiple sclerosis, and severe asthma. While estradiol and progesterone increased IL-17A production in Th17 cells by inhibiting Let7f miRNA expression and increasing IL-23 receptor (IL-23R) expression, it remained unclear how estrogen signaling through the canonical nuclear receptors, estrogen receptor α (ERα) and/or ERβ, regulated this pathway. We hypothesized that estrogen signaling through ERα increased IL-23R expression and IL-17A production from Th17 cells. To test this hypothesis, naïve T cells from WT female, WT male, Esr1^−/− and Esr2^−/− female mice were differentiated into Th17 cells. IL-17A production and IL-23R expression were significantly increased in Th17 cells from WT female mice compared to Th17 cells from WT male mice. Deletion of ERα (Esr1^−/−), but not ERβ (Esr2^−/−), significantly decreased IL-17A production and IL-23R expression in Th17 cells by limiting IL-23R expression in a Let-7f dependent manner. ERα deficiency also decreased Th17 cell proliferation as well as decreased T cell metabolism as measured by ATP-linked oxygen consumption rate and proton leakage. Further, we found that Cox20 expression, a protein involved in mitochondrial respiration through assembly of cytochrome c oxidase in the electron transport chain, was increased in Th17 cells from WT female mice compared to Th17 cells from WT male and Esr1^−/− female mice. Inhibition of Cox20 decreased IL-17 production in Th17 cells from WT female mice. Combined these studies showed that ERα signaling increased IL-17A production in Th17 cells by upregulating IL-23R expression and promoting mitochondrial respiration and proliferation.

Differential estrogen-receptor activation regulates extracellular matrix deposition in human airway smooth muscle remodeling via NF-κB pathway

Altered airway smooth muscle (ASM) mass and extracellular matrix (ECM) deposition in airways are characteristic features of remodeling in asthma. Increased ECM production modulates ASM cell proliferation and leads to airway remodeling. Our previous studies showed that ASM from patients with asthma exhibited increased expression of estrogen receptor (ER)-β, which upon activation down-regulated ASM proliferation, implicating an important role for estrogen signaling in airway physiology. There is no current information on the effect of differential ER activation on ECM production. In this study, we evaluated the effect of ER-α vs. ER-β activation on ECM production, deposition, and underlying pathways. Primary human ASM cells isolated from asthmatics and nonasthmatics were treated with E₂, an ER-α agonist [propylpyrazoletriol (PPT)], and an ER-β agonist [WAY-200070 (WAY)] with TNF-α or platelet-derived growth factor (PDGF) followed by evaluation of ECM production and deposition. Expression of proteins and genes corresponding to ECM were measured using Western blotting and quantitative RT-PCR with subsequent matrix metalloproteinase (MMP) activity. Molecular mechanisms of ER activation in regulating ECM were evaluated by luciferase reporter assays for activator protein 1 (AP-1) and NF-κB. TNF-α or PDGF significantly (P < 0.001) increased ECM deposition and MMP activity in human ASM cells, which was significantly reduced with WAY treatment but not with PPT. Furthermore, TNF-α- or PDGF-induced ECM gene expression in ASM cells was significantly reduced with WAY (P < 0.001). Moreover, WAY significantly down-regulated the activation of NF-κB (P < 0.001) and AP-1 (P < 0.01, P < 0.05) in ASM cells from asthmatics and nonasthmatics. Overall, we demonstrate differential ER signaling in controlling ECM production and deposition. Activation of ER-β diminishes ECM deposition via suppressing the NF-κB pathway activity and might serve as a novel target to blunt airway remodeling.-Ambhore, N. S., Kalidhindi, R. S. R., Pabelick, C. M., Hawse, J. R., Prakash, Y. S., Sathish, V. Differential estrogen-receptor activation regulates extracellular matrix deposition in human airway smooth muscle remodeling via NF-κB pathway.

Estrogen receptors differentially regulate intracellular calcium handling in human nonasthmatic and asthmatic airway smooth muscle cells

Asthma is defined as chronic inflammation of the airways and is characterized by airway remodeling, hyperresponsiveness, and acute bronchoconstriction of airway smooth muscle (ASM) cells. Clinical findings suggest a higher incidence and severity of asthma in adult women, indicating a concrete role of sex steroids in modulating the airway tone. Estrogen, a major female sex steroid mediates its role through estrogen receptors (ER) ERα and ERβ, which are shown to be expressed in human ASM, and their expression is upregulated in lung inflammation and asthma. Previous studies suggested rapid, nongenomic signaling of estrogen via ERs reduces intracellular calcium ([Ca²⁺]_i), thereby promoting relaxation of ASM. However, long-term ER activation on [Ca²⁺]_i regulation in human ASM during inflammation or in asthma is still not known. In Fura-2-loaded nonasthmatic and asthmatic human ASM cells, we found that prolonged (24 h) exposure to ERα agonist (PPT) increased [Ca²⁺]_i response to histamine, whereas ERβ activation (WAY) led to decreased [Ca²⁺] compared with vehicle. This was further confirmed by ER overexpression and knockdown studies using various bronchoconstrictor agents. Interestingly, ERβ activation was more effective than 17β-estradiol in reducing [Ca²⁺]_i responses in the presence of TNF-α or IL-13, while no observable changes were noticed with PPT in the presence of either cytokine. The [Ca²⁺]_i-reducing effects of ERβ were mediated partially via L-type calcium channel inhibition and increased Ca²⁺ sequestration by sarcoplasmic reticulum_. Overall, these data highlight the differential signaling of ERα and ERβ in ASM during inflammation. Specific ERβ activation reduces [Ca²⁺]_i in the inflamed ASM cells and is likely to play a crucial role in regulating ASM contractility, thereby relaxing airways.

Atopic March: Collegium Internationale Allergologicum Update 2020

In recent decades, the worldwide prevalence of allergic disease has increased considerably. The atopic march is a model aimed at explaining the apparent progression of allergic diseases from atopic dermatitis (AD) to allergic asthma (AA) and to allergic rhinitis (AR). It hypothesizes that allergic disease begins, typically in children, with the development of AD, then AA, and finally progresses to AR. This theory has been widely studied in cross-sectional and long-term longitudinal studies and it has been found that as prevalence of AD declines, prevalence of AA increases. A similar relationship is reported between AA and AR. The legitimacy of the atopic march model is, however, currently debated. Epidemiological evidence and criticism of longitudinal studies point to an overstatement of the atopic march's prevalence and incorrect mechanisms, opening a discussion for alternative models to better explain the pathophysiological and epidemiological processes that promote this progression of allergic diseases. Albeit, risk factors for the development and progression of allergic disease, particularly AD, are critical in identifying disease progression. Investigating the role of age, severity, family history, phenotype, and genetic traits may give a better indication into the progression of allergic diseases. In addition, studies following patients from infancy into adulthood and a general increase in longitudinal studies would help broaden the knowledge of allergic disease progression and the atopic march.

Maternal food allergy is associated with daughters' menarche in early adolescence

Rationale

Associations between allergic disease and puberty amongst females have been widely studied. However, this association has received less attention in multigenerational populations. To this end, we sought to examine maternal allergic disease status ever, and daughters’ menarche.

Methods

In a cohort of children born in 1995, in Manitoba, Canada, we considered maternal allergic disease ever to daughters’ age 7–8 years, and daughters’ menarche at ages 12–14 years. We included all participants for whom we had information on both the exposure and the outcome of those eligible. Data were analysed using descriptive statistics and logistic regression, with adjustment for confounding variables.

Results

Overall, the prevalences of maternal allergic diseases were 28.6% for asthma 18.8% for food allergy, 27.3% for eczema and 45.5% for rhinitis. By age 12–14 years, 41.6% (64/159) girls had reached menarche. Maternal food allergy was significantly associated with daughters’ menarche (OR 4.39, 95% CI 1.51–12.73), whereas no association was found for maternal asthma, eczema or rhinitis. With consideration to comorbid disease, a combination of maternal asthma + food allergy was associated with daughters’ menarche by age 12–14 years (OR 6.41; 95% CI 1.32–31.01).

Conclusions

Maternal food allergy ever is associated with daughters’ menarche by age 12–14 years.

Factors related to changes in the asthma male: female ratio by age in 403 Mexican counties

BACKGROUND

Asthma is more frequent in males during childhood and in females after adolescence, which has been attributed to changes in sexual hormones levels.

OBJECTIVE

We explored changes of the asthma male: female ratio (AMFR) by age group in a large population (nationwide), and its ecological association (at county level) with some medical, geographical, or sociodemographic factors.

METHODS

Registries of the largest medical institution in Mexico (∼37.5 million subjects assigned to a family physician) were analyzed and the AMFR calculated using asthma incidences.

RESULTS

In boys, asthma incidence peaked at 0 to 4 years and progressively decreased, reaching a plateau in adulthood. In girls, asthma incidence showed a bimodal pattern, with maximal rates at 0 to 4 years old, and again at 50 to 54 years old. In the ecological analysis performed in more than 400 counties, the AMFR in adults (≥15 years old) inversely correlated with population density (r = -0.256) and altitude (r = -0.144), and directly correlated with acute respiratory tract infections (ARTI, r = 0.215), diabetes (r = 0.186), marginalization (r = 0.179), pneumonias (r = 0.166), and mean maximal temperature (r = 0.142), all with P < .01. In the multiple linear regression, only population density (P < .001) and ARTI (P = .006) remained statistically significant in the final model.

CONCLUSION

Asthma incidence in males and females did not match the expected sexual hormones variations, and other factors such as population density and ARTI also influenced the AMFR. These findings challenge the traditional belief that sexual hormones are major determinants of the AMFR.

Sex Differences in Paediatric and Adult Asthma

Asthma is the most common chronic condition in Western countries. Affecting 1 in 7 children and 1 in 12 adults, asthma is responsible for >350,000 avoidable deaths every year. While most children who develop symptoms of asthma are <5 years of age, the disease is frequently misdiagnosed or not suspected in infants and toddlers. In addition, the prevalence of asthma is different in males and females throughout their lifespan. While boys are more likely to develop asthma than girls, this pattern is reversed after puberty. This indicates that sex-specific factors, such as fluctuations in hormone levels, play a role in the disease's pathogenesis. In this review, the authors discuss recent advances in diagnostic tools for asthma in both adults and children, as well as the influences of BMI, environmental exposures, socioeconomic factors, and sex hormones in the disease's pathogenesis. The review will show that both experimental and epidemiological evidence suggest that circulating sex hormone levels are important contributors to asthma symptoms in post-pubertal females, while their role in males and children has not been yet established. In addition, the mechanisms associated with these hormonal influences on airway inflammation and hyper-reactivity have not been yet elucidated. The authors conclude that different factors affect asthma rates and severity in children and adults, and that more research needs to be conducted to identify the specific contributions of sex hormones. These will allow the development of more personalised asthma treatment strategies for men and women at different stages of life.

Modulation of the lung inflammatory response to ozone by the estrous cycle

Emerging evidence suggests that sex differences exist in the control of lung innate immunity; however, the specific roles of sex hormones in the inflammatory response, and the mechanisms involved are unclear. Here, we investigated whether fluctuations in circulating hormone levels occurring in the mouse estrous cycle could affect the inflammatory response to air pollution exposure. For this, we exposed female mice (C57BL/6J, 8 weeks old) at different phases of the estrous cycle to 2 ppm of ozone or filtered air (FA) for 3 h. Following exposure, we collected lung tissue and bronchoalveolar lavage fluid (BAL), and performed lung function measurements to evaluate inflammatory responses and respiratory mechanics. We found a differential inflammatory response to ozone in females exposed in the luteal phase (metestrus, diestrus) versus the follicular phase (proestrus, estrus). Females exposed to ozone in the follicular phase had significantly higher expression of inflammatory genes, including Ccl2, Cxcl2, Ccl20, and Il6, compared to females exposed in the luteal phase (P < 0.05), and displayed differential activation of regulatory pathways. Exposure to ozone in the follicular phase also resulted in higher BAL neutrophilia, lipocalin levels, and airway resistance than exposure in the luteal phase (P < 0.05). Together, these results show that the effects of ozone exposure in the female lung are affected by the estrous cycle phase, and potentially hormonal status. Future studies investigating air pollution effects and inflammation in women should consider the menstrual cycle phase and/or circulating hormone levels.