Regulation of allergic lung inflammation in rats: interaction between estradiol and corticosterone

The association between age at natural menopause and risk of asthma among postmenopausal women from the Canadian Longitudinal Study on Aging

OBJECTIVE

This study aimed to investigate the association between age at natural menopause and incidence of asthma among postmenopausal Canadian women.

METHODS

Women between the ages of 45-85 yr were followed for a 10-yr period. Analysis was restricted to naturally postmenopausal women who are nonsmokers and did not have asthma prior to menopause. Age at natural menopause was examined using the following categories: 40-44, 45-49, 50-54 (reference), and ≥55. Survival analysis was utilized to determine time to onset of asthma. Multivariable Cox regression analysis was performed to assess the relationship between age at natural menopause and asthma after adjusting for covariates.

RESULTS

The multivariable Cox regression analysis showed a 30% decreased risk of asthma in women with age at natural menopause of 40-44 yr compared with age at natural menopause of 50-54 yr with a hazard ratio of 0.7 (95% confidence interval: 0.49-0.95).

CONCLUSIONS

Women with later ages at natural menopause may be at increased risk for asthma.

Association between Estrogen Exposure and Idiopathic Subglottic Stenosis

OBJECTIVE

Idiopathic subglottic stenosis (iSGS) is a rare, recurrent, fibroinflammatory disease affecting the larynx and proximal trachea. Given it occurs primarily in adult females, estrogen is speculated to play a central pathophysiological role. This study aimed to evaluate relationships between estrogen exposure, disease progression, and recurrence.

METHODS

North American Airway Collaborative (NoAAC) data of adults with iSGS obstructive airway lesions, who underwent index endoscopic airway dilation, were used to identify associations between estrogen exposure, disease characteristics, and time to recurrence (TTR), and interventions were analyzed using Kruskal-Wallis test and Pearson coefficient. Cox proportional hazards regression models compared hazard ratios by estrogen exposure. Kaplan-Meier curves were plotted for TTR based on menopausal status.

RESULTS

In all, 533 females had complete estrogen data (33% premenopausal, 17% perimenopausal, 50% postmenopausal). Median estrogen exposure was 28 years. Overall, there was no dose-response relationship between estrogen exposure and disease recurrence. Premenopausal patients had significantly shorter time from symptom manifestation to diagnosis (1.17 vs. 1.42 years perimenopausal vs. 2.08 years postmenopausal, p < 0.001), shorter time from diagnosis to index endoscopic airway dilation (1.90 vs. 2.50 vs. 3.76 years, p = 0.005), and higher number of procedures (1.73 vs. 1.20 vs. 1.08 procedures, p < 0.001).

CONCLUSIONS

We demonstrate premenopausal patients may have a more aggressive disease variant than their peri- and postmenopausal counterparts. However, it is unclear as to whether this is related to reduced estrogen in the peri- and postmenopausal states or the age-related physiology of wound healing and inflammation, regardless of estrogen.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:825-830, 2024.

Bik promotes proteasomal degradation to control low-grade inflammation

Although chronic low-grade inflammation does not cause immediate clinical symptoms, over the longer term, it can enhance other insults or age-dependent damage to organ systems and thereby contribute to age-related disorders, such as respiratory disorders, heart disease, metabolic disorders, autoimmunity, and cancer. However, the molecular mechanisms governing low-level inflammation are largely unknown. We discovered that Bcl-2-interacting killer (Bik) deficiency causes low-level inflammation even at baseline and the development of spontaneous emphysema in female but not male mice. Similarly, a single nucleotide polymorphism that reduced Bik levels was associated with increased inflammation and enhanced decline in lung function in humans. Transgenic expression of Bik in the airways of Bik-deficient mice inhibited allergen- or LPS-induced lung inflammation and reversed emphysema in female mice. Bik deficiency increased nuclear but not cytosolic p65 levels because Bik, by modifying the BH4 domain of Bcl-2, interacted with regulatory particle non-ATPase 1 (RPN1) and RPN2 and enhanced proteasomal degradation of nuclear proteins. Bik deficiency increased inflammation primarily in females because Bcl-2 and Bik levels were reduced in lung tissues and airway cells of female compared with male mice. Therefore, controlling low-grade inflammation by modifying the unappreciated role of Bik and Bcl-2 in facilitating proteasomal degradation of nuclear proteins may be crucial in treating chronic age-related diseases.

Repurposing Tamoxifen as Potential Host-Directed Therapeutic for Tuberculosis

The global burden of tuberculosis (TB) is aggravated by the continuously increasing emergence of drug resistance, highlighting the need for innovative therapeutic options. The concept of host-directed therapy (HDT) as adjunctive to classical antibacterial therapy with antibiotics represents a novel and promising approach for treating TB. Here, we have focused on repurposing the clinically used anticancer drug tamoxifen, which was identified as a molecule with strong host-directed activity against intracellular Mycobacterium tuberculosis (Mtb). Using a primary human macrophage Mtb infection model, we demonstrate the potential of tamoxifen against drug-sensitive as well as drug-resistant Mtb bacteria. The therapeutic effect of tamoxifen was confirmed in an in vivo TB model based on Mycobacterium marinum infection of zebrafish larvae. Tamoxifen had no direct antimicrobial effects at the concentrations used, confirming that tamoxifen acted as an HDT drug. Furthermore, we demonstrate that the antimycobacterial effect of tamoxifen is independent of its well-known target the estrogen receptor (ER) pathway, but instead acts by modulating autophagy, in particular the lysosomal pathway. Through RNA sequencing and microscopic colocalization studies, we show that tamoxifen stimulates lysosomal activation and increases the localization of mycobacteria in lysosomes both in vitro and in vivo, while inhibition of lysosomal activity during tamoxifen treatment partly restores mycobacterial survival. Thus, our work highlights the HDT potential of tamoxifen and proposes it as a repurposed molecule for the treatment of TB. IMPORTANCE Tuberculosis (TB) is the world's most lethal infectious disease caused by a bacterial pathogen, Mycobacterium tuberculosis. This pathogen evades the immune defenses of its host and grows intracellularly in immune cells, particularly inside macrophages. There is an urgent need for novel therapeutic strategies because treatment of TB patients is increasingly complicated by rising antibiotic resistance. In this study, we explored a breast cancer drug, tamoxifen, as a potential anti-TB drug. We show that tamoxifen acts as a so-called host-directed therapeutic, which means that it does not act directly on the bacteria but helps the host macrophages combat the infection more effectively. We confirmed the antimycobacterial effect of tamoxifen in a zebrafish model for TB and showed that it functions by promoting the delivery of mycobacteria to digestive organelles, the lysosomes. These results support the high potential of tamoxifen to be repurposed to fight antibiotic-resistant TB infections by host-directed therapy.

Impacts of synthetic androgen and estrogenic antagonist administration on growth performance, sex steroids hormones, and immune markers of male and female broilers

The influence of synthetic androgen and estrogenic antagonists (Tamoxifen) on body characteristics and immune response of male and female broilers and the correlation between sex hormone levels were estimated in our experiment. One day old chicks were sexed, and chicks of each sex were randomly distributed on three experimental treatments; the first treatment group (TAM20) chicks were supplied with estrogenic antagonist tamoxifen citrate 20 mg/kg body weight through oral administration for four times every other day from third until ninth d; Androgen treatment chicks were injected intramuscular with veterinary androgen AD GAN@ (Boldenone Undecylenate 50 mg) 1 cm/10 kg body weight at fifth and ninth day, and the third treatment was control. Androgen treatment reported the highest feed intake with the lowest for TAM20 treatment. Concerning carcass characteristics, early androgen injection increased breast percentage significantly compared to TAM20 treatment. Androgen supplementation increased significantly comb the percentage. However, TAM20 decreased it particularly compared to control. Moreover, the percentage of comb and shanks was substantially higher for males than females. Concerning the effects of both treatments on sex hormones, androgen showed favorable effects on testosterone and estrogen compared to Tamoxifen 20 treatment. On the other hand, the administration of TAM 20 improves phagocytic activity compared to androgen administration.

Sex Differences in Mast Cell-Associated Disorders: A Life Span Perspective

Mast cells are critical innate immune effectors located throughout the body that are crucial for host defense mechanisms via orchestrating immune responses to a variety of host and environmental stimuli necessary for survival. The role of mast cells in brain development and behavior, meningeal function, and stress-related disorders has also been increasingly recognized. While critical for survival and development, excessive mast cell activation has been linked with an increasing number of inflammatory, stress-associated, and neuroimmune disorders including allergy/anaphylaxis, autoimmune diseases, migraine headache, and chronic pain disorders. Further, a strong sex bias exists for mast cell-associated diseases with females often at increased risk. Here we review sex differences in human mast cell-associated diseases and animal models, and the underlying biological mechanisms driving these sex differences, which include adult gonadal sex hormones as well the emerging organizational role of perinatal gonadal hormones on mast cell activity and development.

Sex Steroids Effects on Asthma: A Network Perspective of Immune and Airway Cells

A multitude of evidence has suggested the differential incidence, prevalence and severity of asthma between males and females. A compilation of recent literature recognized sex differences as a significant non-modifiable risk factor in asthma pathogenesis. Understanding the cellular and mechanistic basis of sex differences remains complex and the pivotal point of this ever elusive quest, which remains to be clarified in the current scenario. Sex steroids are an integral part of human development and evolution while also playing a critical role in the conditioning of the immune system and thereby influencing the function of peripheral organs. Classical perspectives suggest a pre-defined effect of sex steroids, generalizing estrogens popularly under the “estrogen paradox” due to conflicting reports associating estrogen with a pro- and anti-inflammatory role. On the other hand, androgens are classified as “anti-inflammatory,” serving a protective role in mitigating inflammation. Although considered mainstream and simplistic, this observation remains valid for numerous reasons, as elaborated in the current review. Women appear immune-favored with stronger and more responsive immune elements than men. However, the remarkable female predominance of diverse autoimmune and allergic diseases contradicts this observation suggesting that hormonal differences between the sexes might modulate the normal and dysfunctional regulation of the immune system. This review illustrates the potential relationship between key elements of the immune cell system and their interplay with sex steroids, relevant to structural cells in the pathophysiology of asthma and many other lung diseases. Here, we discuss established and emerging paradigms in the clarification of observed sex differences in asthma in the context of the immune system, which will deepen our understanding of asthma etiopathology.

The anti-inflammatory effect of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice

AIMS

Allergic rhinitis (AR), a major chronic inflammatory disease of the respiratory system, is a public health issue because of its substantial negative impact on quality of life and work efficiency alongside its high prevalence and costs. Dapsone is a sulfone chemical with reported anti-inflammatory and antibacterial properties. Accordingly, we investigated the anti-inflammatory impact of dapsone on ovalbumin-induced allergic rhinitis in balb/c mice.

MAIN METHODS

Intraperitoneal ovalbumin and hydroxide aluminum injection followed by intranasal ovalbumin administration sensitized female Balb/c mice. Mice received intraperitoneal dapsone either acute (5, 10, 20 mg/kg) 30 min before the last ovalbumin challenge, or chronic (20 mg/kg) on days 21 to 35.

KEY FINDINGS

Both acute and chronic intraperitoneal usage of dapsone showed a considerable decrease in the nasal scratching behavior, the number of sneezing, serum IL-4 and IgE levels of ovalbumin-induced AR in balb/c mice, but there was a significant increase in serum IFNγ level. Histopathological analysis demonstrated a significant reduction of eosinophil numbers, following dapsone injection. Goblet cell hyperplasia and respiratory epithelial-thickness decreased significantly in the acute and chronic 20 mg/kg dapsone groups compared to the ovalbumin-induced controls.

SIGNIFICANCE

This study shows that there is an association between acute and chronic dapsone treatment and some anti-allergic effects through an inflammation cascade.

Sex-Steroid Signaling in Lung Diseases and Inflammation

Sex/gender difference exists in the physiology of multiple organs. Recent epidemiological reports suggest the influence of sex-steroids in modulating a wide variety of disease conditions. Sex-based discrepancies have been reported in pulmonary physiology and various chronic inflammatory responses associated with lung diseases like asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and rare lung diseases. Notably, emerging clinical evidence suggests that several respiratory diseases affect women to a greater degree, with increased severity and prevalence than men. Although sex-specific differences in various lung diseases are evident, such differences are inherent to sex-steroids, which are major biological variables in men and women who play a central role to control these differences. The focus of this chapter is to comprehend the sex-steroid biology in inflammatory lung diseases and to understand the mechanistic role of sex-steroids signaling in regulating these diseases. Exploring the roles of sex-steroid signaling in the regulation of lung diseases and inflammation is crucial for the development of novel and effective therapy. Overall, we will illustrate the importance of differential sex-steroid signaling in lung diseases and their possible clinical implications for the development of complementary and alternative medicine to treat lung diseases.

Pharmacotherapeutic management of asthma in pregnancy and the effect of sex hormones

INTRODUCTION

Asthma is a common medical condition that can frequently affect pregnancy, and thus optimal management of asthma in pregnancy is important for both mother and baby. This article reviews recent developments of asthma pharmacotherapy and provides emerging data on the safety of asthma controller medications and biological therapies in pregnancy. The authors highlight the clinical outcomes of asthma during pregnancy, and summarize emerging new data related to the influence of sex hormones and fetal sex on asthma severity.

AREAS COVERED

This review of asthma pharmacotherapy during pregnancy examines the recent guidelines and reports the most pertinent publications on safety data and asthma management.

EXPERT OPINION

Asthma management during pregnancy follows the same principles as that of non-pregnant asthma. The available data for most asthma medications are reassuring, however there is a lack of adequate safety data available because pregnant women are generally excluded from clinical trials. More clarity is needed in guidelines regarding the management of asthma in pregnancy, and high-quality randomized control trials are required to strengthen the evidence base and inform future guidelines. In particular, safety studies examining biological therapies in pregnant women with severe asthma are needed.

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.

Mast Cells as a Double-Edged Sword in Immunity: Their Function in Health and Disease. First of Two Parts

Mast cells (MCs) have recently been re-interpreted in the context of the immune scenario in the sense that their pro-allergic role is no longer exclusive. In fact, MCs even in steady state conditions maintain homeostatic functions, producing mediators and intensively cross-talking with other immune cells. Here, emphasis will be placed on the array of receptors expressed by MCs and the variety of cytokines they produce. Then, the bulk of data discussed will provide readers with a wealth of information on the dual ability of MCs not only to defend but also to offend the host. This double attitude of MCs relies on many variables, such as their subsets, tissues of residency and type of stimuli ranging from microbes to allergens and food antigens. Finally, the relationship between MCs with basophils and eosinophils will be discussed.

Inflammatory and functional responses after (bio)diesel exhaust exposure in allergic sensitized mice. A comparison between diesel and biodiesel

Many cities fail to meet air quality standards, which results in increased risk for pulmonary disorders, including asthma. Human and experimental studies have shown that diesel exhaust (DE) particles are associated with worsening of allergic asthma. Biodiesel (BD), a cleaner fuel from renewable sources, was introduced in the eighties. Because of the reduction in particulate matter (PM) emissions, BD was expected to cause fewer adverse pulmonary effects. However, only limited data on the effect of BD emissions in asthma are available.

OBJECTIVE

Determine whether BD exhaust exposure in allergic sensitized mice leads to different effects on inflammatory and functional responses compared to DE exposure.

METHODS

Balb/C mice were orotracheally sensitized with House Dust Mite (HDM) or a saline solution with 3 weekly instillations. From day 9 until day 17 after sensitization, they were exposed daily to filtered air (FA), DE and BD exhaust (concentration: 600 μg/m³ PM_2.5). Lung function, bronchoalveolar lavage fluid (BALF) cell counts, cytokine levels (IL-2, IL-4, IL-5, IL-17, TNF-α, TSLP) in the BALF, peribronchiolar eosinophils and parenchymal macrophages were measured.

RESULTS

HDM-sensitized animals presented increased lung elastance (p = 0.046), IgG1 serum levels (p = 0.029), peribronchiolar eosinophils (p = 0.028), BALF levels of total cells (p = 0.020), eosinophils (p = 0.028), IL-5 levels (p = 0.002) and TSLP levels (p = 0.046) in BALF. DE exposure alone increased lung elastance (p = 0.000) and BALF IL-4 levels (p = 0.045), whereas BD exposure alone increased BALF TSLP levels (p = 0.004). BD exposure did not influence any parameters after HDM challenge, while DE exposed animals presented increased BALF levels of total cells (p = 0.019), lymphocytes (p = 0.000), neutrophils (p = 0.040), macrophages (p = 0.034), BALF IL-4 levels (p = 0.028), and macrophagic inflammation in the lung tissue (p = 0.037), as well as decreased IgG1 (p = 0.046) and IgG2 (p = 0.043) levels when compared to the HDM group.

CONCLUSION

The results indicate more adverse pulmonary effects of DE compared to BD exposure in allergic sensitized animals.

17β-Estradiol affects lung function and inflammation following ozone exposure in a sex-specific manner

Inflammatory lung diseases affect men and women disproportionately, suggesting that fluctuations of circulating hormone levels mediate inflammatory responses. Studies have shown that ozone exposure contributes to lung injury and impairment of innate immunity with differential effects in men and women. Here, we hypothesized that 17β-estradiol enhances inflammation and airway hyperresponsiveness (AHR), triggered by ozone exposure, in the female lung. We performed gonadectomy and hormone treatment (17β-estradiol, 2 wk) in C57BL/6J female and male mice and exposed animals to 1 ppm of ozone or filtered air for 3 h. Twenty-four hours later, we tested lung function, inflammatory gene expression, and changes in bronchoalveolar lavage fluid (BALF). We found increased AHR and expression of inflammatory genes after ozone exposure. These changes were higher in females and were affected by gonadectomy and 17β-estradiol treatment in a sex-specific manner. Gonadectomized male mice displayed higher AHR and inflammatory gene expression than controls exposed to ozone; 17β-estradiol treatment did not affect this response. In females, ovariectomy reduced ozone-induced AHR, which was restored by 17β-estradiol treatment. Ozone exposure also increased BALF lipocalin-2, which was reduced in both male and female gonadectomized mice. Treatment with 17β-estradiol increased lipocalin-2 levels in females but lowered them in males. Gonadectomy also reduced ozone-induced expression of lung IL-6 and macrophage inflammatory protein-3 in females, which was restored by treatment with 17β-estradiol. Together, these results indicate that 17β-estradiol increases ozone-induced inflammation and AHR in females but not in males. Future studies examining diseases associated with air pollution exposure should consider the patient's sex and hormonal status.

Sex difference in IgE sensitization associated with alcohol consumption in the general population

The association of alcohol consumption and immunoglobulin E (IgE) sensitization is debated. Few population-based studies have investigated whether such associations differ by sex. We explored the association of alcohol consumption with IgE sensitization in the general population, stratified by sex. We analyzed data for 1,723 adults from the 2010 Korean National Health and Nutrition Examination Survey. We divided subjects into three groups according to their self-reported alcohol consumption or serum level of gamma-glutamyltransferase (GGT), an objective marker of alcohol consumption. After adjustments, the odds ratios (ORs) of male high-risk drinkers were 2.09 (95% confidence interval [CI], 1.34–3.28) for total IgE and 1.71 (95% CI, 1.03–2.83) for Dermatophagoides farinae (DF)-specific IgE compared with male low-risk drinkers. In females, the dog-specific IgE level was associated with high-risk drinking (OR, 11.74; 95% CI, 2.04–67.24). The ORs of males in the high-serum-GGT group were 2.73 (95% CI, 1.72–4.33) for total IgE and 2.17 (95% CI, 1.35–3.47) for DF-specific IgE compared with those in the low-serum-GGT group. This study suggests a possible link between alcohol consumption and IgE sensitization, moreover, the risk of IgE sensitization was significantly higher in male high-risk drinkers. Therefore, clinicians should consider the risk of IgE sensitization possibly afflicting male high-risk drinkers.

Estrogen ameliorates allergic airway inflammation by regulating activation of NLRP3 in mice

Background: Estrogen has been suggested to play a protective role against airway inflammations, such as asthma. In these processes, the inflammasome nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain containing 3 (NLRP3) partly accounts for the activation of pro-inflammatory factors. The aim of the present study was to investigate whether NLRP3 was involved in the protective effect of estrogen against allergic airway inflammation. Methods: An ovariectomy was performed on female C57BL/6 mice; some were sham-operated (sham). We then sensitized and challenged them with ovalbumin (OVA) to establish an airway inflammation model. Meanwhile, some mice were treated with 17β-estradiol (E2) for 28 days. Results: The expression of NLRP3 inflammasome and its downstream products, caspase-1 and the pro-inflammatory cytokine interleukin (IL)-1β (IL-1β), increased concomitantly with OVA-challenged airway inflammation and decreased with the expression of estrogen receptor β (ERβ). In addition, treating ovariectomized (OVX) mice with E2 dramatically ameliorated airway inflammation via such mechanisms as leukocyte recruitment, mucus production, and secretion of pro-inflammatory cytokines other than IL-18 in bronchoalveolar lavage (BAL) fluid (BALF). Furthermore, E2 suppressed both the mRNA expression and protein expression of NLRP3, caspase-1, and IL-1β. In summary, our study showed that NLRP3 inflammasome activation and pro-inflammatory cytokine production markedly increased in OVA-induced airway inflammation, and E2 effectively abrogated such inflammation by regulating the activation of NLRP3.

Welding fume exposure is associated with inflammation: a global metabolomics profiling study

BACKGROUND

Increasing evidence suggests that welding fume exposure is associated with systemic inflammation. Although celluar metabolites may be associated with inflammation, there is limited information on metabolomic changes during welding fume exposure. Such changes may play an important role in the occurrence, development, and prevention of metal-associated diseases. We aim to investigate human metabolomics changes pre- and post-welding fume exposure.

METHODS

This study included 52 boilermakers totally. We collected plasma samples pre- and post-shift welding fume exposure and prepared samples using the automated MicroLab STAR® system. Metabolite concentrations were measured using ultra performance liquid chromatography - tandem mass spectrometer (UPLC-MS/MS) methods. Two-way analysis of variance was used to test the significance of metabolite changes with false discovery rate correction.

RESULTS

Analysis detected several metabolic changes after welding fume exposure, mainly involved in the lipid pathway [glucocorticoid class (cortisol, corticosterone, and cortisone), acylcarnitine class, and DiHOME species (9,10-DiHOME and 12,13-DiHOME)], amino acid utilization (isoleucine, proline and phenylalanine), and S-(3-hydroxypropyl) mercapturic acid (3-HPMA). These compounds are all associated with inflammation according to previous studies. Further, additive interaction effects linked smoking and 3-HPMA levels. In the metabolite set enrichment analysis for diseases, the top two disease-associated metabolite pathways were systemic inflammation-related diseases including rheumatoid arthritis and systemic lupus erythematosus.

CONCLUSIONS

This global metabolomics study shows evidence that metabolite changes during welding fume exposure are closely associated with systemic inflammation. The altered metabolites detected may be potential health monitoring biomarkers for boilermakers, especially for inflammation-related disease prevention.

Immunological Processes Driving IgE Sensitisation and Disease Development in Males and Females

IgE sensitisation has increased significantly over the last decades and is a crucial factor in the development of allergic diseases. IgE antibodies are produced by B cells through the process of antigen presentation by dendritic cells, subsequent differentiation of CD4⁺ Th2 cells, and class switching in B cells. However, many of the factors regulating these processes remain unclear. These processes affect males and females differently, resulting in a significantly higher prevalence of IgE sensitisation in males compared to females from an early age. Before the onset of puberty, this increased prevalence of IgE sensitisation is also associated with a higher prevalence of clinical symptoms in males; however, after puberty, females experience a surge in the incidence of allergic symptoms. This is particularly apparent in allergic asthma, but also in other allergic diseases such as food and contact allergies. This has been partly attributed to the pro- versus anti-allergic effects of female versus male sex hormones; however, it remains unclear how the expression of sex hormones translates IgE sensitisation into clinical symptoms. In this review, we describe the recent epidemiological findings on IgE sensitisation in male and females and discuss recent mechanistic studies casting further light on how the expression of sex hormones may influence the innate and adaptive immune system at mucosal surfaces and how sex hormones may be involved in translating IgE sensitisation into clinical manifestations.

Roads Less Traveled: Sexual Dimorphism and Mast Cell Contributions to Migraine Pathology

Migraine is a common, little understood, and debilitating disease. It is much more prominent in women than in men (~2/3 are women) but the reasons for female preponderance are not clear. Migraineurs frequently experience severe comorbidities, such as allergies, depression, irritable bowel syndrome, and others; many of the comorbidities are more common in females. Current treatments for migraine are not gender specific, and rarely are migraine and its comorbidities considered and treated by the same specialist. Thus, migraine treatments represent a huge unmet medical need, which will only be addressed with greater understanding of its underlying pathophysiology. We discuss the current knowledge about sex differences in migraine and its comorbidities, and focus on the potential role of mast cells (MCs) in both. Sex-based differences in pain recognition and drug responses, fluid balance, and the blood–brain barrier are recognized but their impact on migraine is not well studied. Furthermore, MCs are well recognized for their prominent role in allergies but much less is known about their contributions to pain pathways in general and migraine specifically. MC-neuron bidirectional communication uniquely positions these cells as potential initiators and/or perpetuators of pain. MCs can secrete nociceptor sensitizing and activating agents, such as serotonin, prostaglandins, histamine, and proteolytic enzymes that can also activate the pain-mediating transient receptor potential vanilloid channels. MCs express receptors for both estrogen and progesterone that induce degranulation upon binding. Furthermore, environmental estrogens, such as Bisphenol A, activate MCs in preclinical models but their impact on pain pathways or migraine is understudied. We hope that this discussion will encourage scientists and physicians alike to bridge the knowledge gaps linking sex, MCs, and migraine to develop better, more comprehensive treatments for migraine patients.

Asthma and Risk of Stroke: A Systematic Review and Meta-analysis

BACKGROUND

Several studies have suggested that asthma is associated with an increased risk of stroke. However, the results are inconsistent. The aim of this study is to investigate the relation of asthma and the risk of stroke through a systematic review and meta-analysis of published research.

METHODS

Pertinent studies were identified by a search of the PubMed and the Web of Science databases to June 2015. Study-specific hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled using fixed-effect or random-effect models when appropriate. Associations were tested in subgroups representing different participants and study characteristics. Publication bias was assessed with Egger's test.

RESULTS

Five articles comprising 524,637 participants and 6031 stroke cases were eligible for inclusion. Asthma was associated significantly with increased risk of stroke, and the pooled HR was 1.32 (95% CI: 1.13, 1.54, I(2)=80.4%). Subgroup analyses revealed that the association between asthma and stroke risk was stronger among female patients (HR = 1.42, 95% CI: 1.15-1.76) and prospective cohort study design (HR = 1.52, 95% CI: 1.21-1.91).

CONCLUSION

Asthma is associated with a significantly increased risk of stroke. This finding may have clinical and public health importance.

Increasing awareness of sex differences in airway diseases

There is growing epidemiologic data demonstrating sex differences with respect to prevalence and progression of airway diseases, including asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) and non-CF-related bronchiectasis. In asthma, for example, young boys have increased exacerbations and higher morbidity than girls which distinctly reverses after adolescence and into adulthood. In COPD, a disease that was historically considered an illness of men, the number of women dying per year is now greater than in men. Finally, women with CF-related bronchiectasis have a decreased median life expectancy relative to men and a higher risk of respiratory infections despite equal prevalence of the disease. A number of studies now exist demonstrating mechanisms behind these sex differences, including influences of genetic predisposition, sex hormones and comorbidities. The notable sex disparity has potential diagnostic, therapeutic and prognostic implications and for the practicing respiratory or general physician, a familiarity with these distinctions may augment effective management of patients with airway diseases. This review seeks to concisely summarize the data regarding gender-based differences in airway diseases, outline the current understanding of contributing factors and discuss therapeutic implications for clinicians.

Sexual maturation protects against development of lung inflammation through estrogen

Increasing levels of estrogen and progesterone are suggested to play a role in the gender switch in asthma prevalence during puberty. We investigated whether the process of sexual maturation in mice affects the development of lung inflammation in adulthood and the contributing roles of estrogen and progesterone during this process. By inducing ovalbumin-induced lung inflammation in sexually mature and immature (ovariectomized before sexual maturation) adult mice, we showed that sexually immature adult mice developed more eosinophilic lung inflammation. This protective effect of "puberty" appears to be dependent on estrogen, as estrogen supplementation at the time of ovariectomy protected against development of lung inflammation in adulthood whereas progesterone supplementation did not. Investigating the underlying mechanism of estrogen-mediated protection, we found that estrogen-treated mice had higher expression of the anti-inflammatory mediator secretory leukoprotease inhibitor (SLPI) and lower expression of the proasthmatic cytokine IL-33 in parenchymal lung tissue and that their expressions colocalized with type II alveolar epithelial cells (AECII). Treating AECII directly with SLPI significantly inhibited IL-33 production upon stimulation with ATP. Our data suggest that estrogen during puberty has a protective effect on asthma development, which is accompanied by induction of anti-inflammatory SLPI production and inhibition of proinflammatory IL-33 production by AECII.

Genetic Deletion of β-Arrestin-2 and the Mitigation of Established Airway Hyperresponsiveness in a Murine Asthma Model

β-Arrestin-2 (βarr2) is a ubiquitously expressed cytosolic protein that terminates G protein-coupled receptor signaling and transduces G protein-independent signaling. We previously showed that mice lacking βarr2 do not develop an asthma phenotype when sensitized to, and challenged with, allergens. The current study evaluates if an established asthma phenotype can be mitigated by deletion of βarr2 using an inducible Cre recombinase. We sensitized and challenged mice to ovalbumin (OVA) and demonstrated that on Day (d) 24 the allergic asthma phenotype was apparent in uninduced βarr2 and wild-type (WT) mice. In a second group of OVA-treated mice, tamoxifen was injected on d24 to d28 to activate Cre recombinase, and OVA aerosol challenge was continued through d44. The asthma phenotype was assessed using lung mechanics measurements, bronchoalveolar lavage cell analysis, and histological assessment of mucin and airway inflammation. Compared with their respective saline-treated controls, OVA-treated WT mice and mice expressing the inducible Cre recombinase displayed a significant asthma phenotype at d45. Whereas tamoxifen treatment had no significant effect on the asthma phenotype in WT mice, it inhibited βarr2 expression and caused a significant reduction in airway hyper-responsiveness (AHR) in Cre-inducible mice. These findings suggest that βarr2 is actively required for perpetuation of the AHR component of the allergic asthma phenotype. Our finding that βarr2 participates in the perpetuation of AHR in an asthma model means that targeting βarr2 may provide immediate and potentially long-term relief from daily asthma symptoms due to AHR irrespective of inflammation.

Tamoxifen augments the innate immune function of neutrophils through modulation of intracellular ceramide

Tamoxifen is a selective estrogen receptor modulator widely used for the treatment of breast cancer. In addition to its activity as an estrogen receptor agonist/antagonist, tamoxifen also modulates sphingolipid biosynthesis, which has been shown to play an important role in the regulation of neutrophil activity. Here, we find that tamoxifen stimulation enhances several pro-inflammatory pathways in human neutrophils, including chemotaxis, phagocytosis and neutrophil extracellular trap (NET) formation. The enhancement of NET production occurs via a ceramide/PKCζ-mediated pathway, and treatment with synthetic ceramide is sufficient to promote NET formation. Pretreatment of human neutrophils with tamoxifen boosts neutrophil bactericidal capacity against a variety of pathogens in vitro and enhances clearance of the leading human pathogen methicillin-resistant Staphylococcus aureus in vivo. Our results suggest that tamoxifen, and the lipid signaling pathways it modulates, merit further exploration as targets for boosting host innate immune function.

Phenotypes, Risk Factors, and Mechanisms of Adult-Onset Asthma

Asthma is a heterogeneous disease with many phenotypes, and age at disease onset is an important factor in separating the phenotypes. Genetic factors, atopy, and early respiratory tract infections are well-recognized factors predisposing to childhood-onset asthma. Adult-onset asthma is more often associated with obesity, smoking, depression, or other life-style or environmental factors, even though genetic factors and respiratory tract infections may also play a role in adult-onset disease. Adult-onset asthma is characterized by absence of atopy and is often severe requiring treatment with high dose of inhaled and/or oral steroids. Variety of risk factors and nonatopic nature of adult-onset disease suggest that variety of mechanisms is involved in the disease pathogenesis and that these mechanisms differ from the pathobiology of childhood-onset asthma with prevailing Th2 airway inflammation. Recognition of the mechanisms and mediators that drive the adult-onset disease helps to develop novel strategies for the treatment. The aim of this review was to summarize the current knowledge on the pathogenesis of adult-onset asthma and to concentrate on the mechanisms and mediators involved in establishing adult-onset asthma in response to specific risk factors. We also discuss the involvement of these mechanisms in the currently recognized phenotypes of adult-onset asthma.

Phase II study evaluating efficacy and safety of everolimus with letrozole for management of advanced (unresectable or metastatic) non-small cell lung cancer after failure of platinum-based treatment: a preliminary analysis of toxicity

INTRODUCTION

Lung cancer is one of the most common malignancies worldwide. Non-small cell lung cancer (NSCLC) comprises the majority of the cases of lung cancer. Previous studies have demonstrated a role for both the estrogen pathway and mammalian target of rapamycin (mTOR) in NSCLC.

METHODS

This single-arm phase 2 study was designed to assess the safety and efficacy of combination treatment with aromatase inhibitor—letrozole—and mTOR inhibitor—everolimus—in the treatment of patients with advanced (unresectable stage III or stage IV) NSCLC who had failed at least one line of platinum-based chemotherapy.

RESULTS

The study was closed after enrolling five patients due to safety concerns. Of the five patients treated with the study combination, two patients developed grade 5 pulmonary toxicity and another patient developed reversible grade 4 pulmonary toxicity.

CONCLUSIONS

There is a probable causal relationship between the study medication and the reported serious adverse events. In the absence of additional clinical data in lung cancer patients, we recommend that extreme caution be exercised in the use of combined letrozole and everolimus regimens in patients with advanced lung cancers, active pulmonary pathologies, or both.

In vivo genotoxicity evaluation of lung cells from Fischer 344 rats following 28 days of inhalation exposure to MWCNTs, plus 28 days and 90 days post-exposure

Despite their useful physico-chemical properties, carbon nanotubes (CNTs) continue to cause concern over occupational and human health due to their structural similarity to asbestos. Thus, to evaluate the toxic and genotoxic effect of multi-wall carbon nanotubes (MWCNTs) on lung cells in vivo, eight-week-old rats were divided into four groups (each group = 25 animals), a fresh air control (0 mg/m(3)), low (0.17 mg/m(3)), middle (0.49 mg/m(3)), and high (0.96 mg/m(3)) dose group, and exposed to MWCNTs via nose-only inhalation 6 h per day, 5 days per week for 28 days. The count median length and geometric standard deviation for the MWCNTs determined by TEM were 330.18 and 1.72 nm, respectively, and the MWCNT diameters ranged from 10 to 15 nm. Lung cells were isolated from five male and five female rats in each group on day 0, day 28 (only from males) and day 90 following the 28-day exposure. The total number of animals used was 15 male and 10 female rats for each concentration group. To determine the genotoxicity of the MWCNTs, a single cell gel electrophoresis assay (Comet assay) was conducted on the rat lung cells. As a result of the exposure, the olive tail moments were found to be significantly higher (p < 0.05) in the male and female rats from all the exposed groups when compared with the fresh air control. In addition, the high-dose exposed male and middle and high-dose exposed female rats retained DNA damage, even 90 days post-exposure (p < 0.05). To investigate the mode of genotoxicity, the intracellular reactive oxygen species (ROS) levels and inflammatory cytokine levels (TNF-α, TGF- β, IL-1, IL-2, IL-4, IL-5, IL-10, IL-12 and IFN-γ) were also measured. For the male rats, the H2O2 levels were significantly higher in the middle (0 days post-exposure) and high- (0 days and 28 days post-exposure) dose groups (p < 0.05). Conversely, the female rats showed no changes in the H2O2 levels. The inflammatory cytokine levels in the bronchoalveolar lavage (BAL) fluid did not show any statistically significant difference. Interestingly, the short-length MWCNTs deposited in the lung cells were persistent at 90 days post-exposure. Thus, exposing lung cells to MWCNTs with a short tube length may induce genotoxicity.

The putative role of ovary removal and progesterone when considering the effect of formaldehyde exposure on lung inflammation induced by ovalbumin

OBJECTIVE

Formaldehyde exposure during the menstrual cycle is known to affect the course of allergic lung inflammation. Because our previous data demonstrated that formaldehyde combined with an ovariectomy reduced allergic lung inflammation, we investigated the putative role of ovary removal and progesterone treatment when considering the effect of formaldehyde on allergic lung inflammation.

METHOD

Ovariectomized rats and their matched controls were exposed to formaldehyde (1%, 3 days, 90 min/day) or vehicle, and immediately after exposure, the rats were sensitized to ovalbumin by a subcutaneous route. After 1 week, the rats received a booster by the same route, and after an additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability, ex vivo tracheal reactivity to methacholine and mast cell degranulation were determined 24 h later.

RESULTS

Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure on ex vivo tracheal reactivity, cell influx into the lungs and mast cell degranulation.

CONCLUSION

In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation.

Ovariectomized OVA-sensitized mice display increased frequency of CD4(+)Foxp3(+) T regulatory cells in the periphery

It is well established that female sex hormones have a pivotal role in inflammation. For instance, our group has previously reported that estradiol has proinflammatory actions during allergic lung response in animal models. Based on these findings, we have decided to further investigate whether T regulatory cells are affected by female sex hormones absence after ovariectomy. We evaluated by flow cytometry the frequencies of CD4⁺Foxp3⁺ T regulatory cells (Tregs) in central and peripheral lymphoid organs, such as the thymus, spleen and lymph nodes. Moreover, we have also used the murine model of allergic lung inflammation a to evaluate how female sex hormones would affect the immune response in vivo. To address that, ovariectomized or sham operated female Balb/c mice were sensitized or not with ovalbumin 7 and 14 days later and subsequently challenged twice by aerosolized ovalbumin on day 21. Besides the frequency of CD4⁺Foxp3⁺ T regulatory cells, we also measured the cytokines IL-4, IL-5, IL-10, IL-13 and IL-17 in the bronchoalveolar lavage from lungs of ovalbumine challenged groups. Our results demonstrate that the absence of female sex hormones after ovariectomy is able to increase the frequency of Tregs in the periphery. As we did not observe differences in the thymus-derived natural occurring Tregs, our data may indicate expansion or conversion of peripheral adaptive Tregs. In accordance with Treg suppressive activity, ovariectomized and ovalbumine-sensitized and challenged animals had significantly reduced lung inflammation. This was observed after cytokine analysis of lung explants showing significant reduction of pro-inflammatory cytokines, such as IL-4, IL-5, IL-13 and IL-17, associated to increased amount of IL-10. In summary, our data clearly demonstrates that OVA sensitization 7 days after ovariectomy culminates in reduced lung inflammation, which may be directly correlated with the expansion of Tregs in the periphery and further higher IL-10 secretion in the lungs.

Adult asthma and risk of coronary heart disease, cerebrovascular disease, and heart failure: a prospective study of 2 matched cohorts

Asthma has been associated with increased cardiovascular disease (CVD) risk. The authors ascertained the association of asthma with CVD and the roles that sex, concurrent allergy, and asthma medications may play in this association. They assembled a cohort of 203,595 Northern California adults with asthma and a parallel asthma-free referent cohort (matched 1:1 on age, sex, and race/ethnicity); both cohorts were followed for incident nonfatal or fatal CVD and all-cause mortality from January 1, 1996, through December 31, 2008. Each cohort was 66% female and 47% white. After adjustment for age, sex, race/ethnicity, cardiac risk factors, and comorbid allergy, asthma was associated with a 1.40-fold (95% confidence interval (CI): 1.35, 1.45) increased hazard of coronary heart disease, a 1.20-fold (95% CI: 1.15, 1.25) hazard of cerebrovascular disease, a 2.14-fold (95% CI: 2.06, 2.22) hazard of heart failure, and a 3.28-fold (95% CI: 3.15, 3.41) hazard of all-cause mortality. Stronger associations were noted among women. Comorbid allergy predicted CVD but did not synergistically increase the CVD risk associated with asthma. Only asthma patients using asthma medications (particularly those on oral corticosteroids alone or in combination) were at enhanced risk of CVD. In conclusion, asthma was prospectively associated with increased risk of major CVD. Modifying effects were noted for sex and asthma medication use but not for comorbid allergy.

Role of female sex hormones, estradiol and progesterone, in mast cell behavior

Female sex hormones have long been suspected to have an effect on mast cell (MC) behavior. This assumption is based on the expression of hormone receptors in MCs as well as on the fact that many MC-related pathophysiological alterations have a different prevalence in females than in males. Further, serum IgE levels are much higher in allergic female mice compared to male mice. Ovariectomized rats developed less airway inflammation compared to sham controls. Following estrogen replacement ovariectomized rats re-established airway inflammation levels’ found in intact females. In humans, a much higher asthma prevalence was found in women at reproductive age as compared to men. Serum levels of estradiol and progesterone have been directly correlated with the clinical and functional features of asthma. Around 30–40% of women who have asthma experienced worsening of their symptoms during the perimenstrual phase, the so-called perimenstrual asthma. Postmenopausal women receiving hormone replacement therapy have an increased risk of new onset of asthma. Beside, estrus cycle dependent changes on female sex hormones are related to changes on MC number in mouse uterine tissue and estradiol and progesterone were shown to induce uterine MC maturation and degranulation. We will discuss here the currently available information concerning the role of these female sex hormones on MC behavior.

Gonadal hormones and oxidative stress interaction differentially affects survival of male and female mice after lung Klebsiella pneumoniae infection

Survival of mice after Klebsiella pneumoniae infection and phagocytosis by alveolar macrophages (AMs), in the presence or absence of ozone (O(3)) exposure prior to infection, is sex dependent. The objective of this work was to study the role of gonadal hormones, 5α-dihydrotestosterone (DHT) and 17β-estradiol (E(2)), on mouse survival after filtered air (FA) or O(3) exposure. Gonadectomized female (G×F) and male (G×M) mice implanted with control or hormone pellets (DHT in G×F, or E(2) in G×M), exposed to O(3) (2 ppm, 3h) or FA, and infected with K. pneumoniae were monitored for survival. Survival in G×F was identical after FA or O(3) exposure; in G×M O(3) exposure resulted in lower survival compared to FA. In O(3)-exposed females, gonadectomy resulted in increased survival compared to intact females or to G×M+E(2). A similar effect was observed in G×F+DHT. The combined negative effect of oxidative stress and hormone on survival was higher for E(2). Gonadectomy eliminated (females) or minimized (males) the previously observed sex differences in survival in response to oxidative stress, and hormone treatment restored them. These findings indicate that gonadal hormones and/or oxidative stress have a significant effect on mouse survival.

Estrogen stimulates Th2 cytokine production and regulates the compartmentalisation of eosinophils during allergen challenge in a mouse model of asthma

BACKGROUND

The observation that asthma becomes more prevalent following puberty in females suggests estrogen potentiates the development of this disease. However, most studies examining the role of estrogen in rodent models of asthma are complicated by their reliance on ovariectomised mice in which hormones other than estrogen are also attenuated.

METHODS

We aimed to understand the influence of estrogen on allergic airway disease by using type I (tamoxifen) or type II (ICI 182,780) antagonists in female mice or delivering estradiol to male mice during aeroallergen challenge.

RESULTS

The antagonists showed that estrogen promoted both the mobilisation of bone marrow eosinophils and egression of eosinophils to the airway lumen. These findings were corroborated in male mice treated with estradiol, which increased eosinophil numbers in both blood and airways. Estrogen stimulated goblet cell hyperplasia and baseline lung resistance, but had little effect on the number of eosinophils in the bronchial submucosa or methacholine-induced airway hyperreactivity. Estrogen receptor α was expressed by CD4+ T cells from allergic mice, and estrogen promoted the production of IL-5 and IL-13, and suppressed the production of the eicosanoid 12-HETE by mediastinal lymph node cells.

CONCLUSIONS

These data show that during aeroallergen challenge, estrogen stimulates Th2 cytokine production, which may be linked to its ability to suppress 12-HETE. Lung resistance at baseline, goblet cell hyperplasia and the compartmentalisation of eosinophils was also influenced by estrogen. However, estrogen does not play a major role in stimulating enhanced sensitivity to methacholine-induced lung resistance.

Recovery from silver-nanoparticle-exposure-induced lung inflammation and lung function changes in Sprague Dawley rats

In a previous study, the lung function, as indicated by the tidal volume, minute volume, and peak inspiration flow, decreased during 90 days of exposure to silver nanoparticles and was accompanied by inflammatory lesions in the lung morphology. Therefore, this study investigated the recovery from such lung function changes in rats following the cessation of 12 weeks of nanoparticle exposure. Male and female rats were exposed to silver nanoparticles (14-15 nm diameter) at concentrations of 0.66 × 10(6) particles/cm(3) (49 μg/m(3), low dose), 1.41 × 10(6) particles/cm(3) (117 μg/m(3), middle dose), and 3.24 × 10(6) particles/cm(3) (381 μg/m(3), high dose) for 6 h/day in an inhalation chamber for 12 weeks. The rats were then allowed to recover. The lung function was measured every week during the exposure period and after the cessation of exposure, plus animals were sacrificed after the 12-week exposure period, and 4 weeks and 12 weeks after the exposure cessation. An exposure-related lung function decrease was measured in the male rats after the 12-week exposure period and 12 weeks after the exposure cessation. In contrast, the female rats did not show a consistent lung function decrease either during the exposure period or following the exposure cessation. The histopathology showed a gradual recovery from the lung inflammation in the female rats, whereas the male rats in the high-dose group exhibited persistent inflammation throughout the 12-week recovery period. Therefore, the present results suggest a potential persistence of lung function changes and inflammation induced by silver nanoparticle exposure above the no observed adverse effect level.

Effects of repeated stress on distal airway inflammation, remodeling and mechanics in an animal model of chronic airway inflammation

BACKGROUND/AIMS

Epidemiological studies suggest that stress has an impact on asthmatic exacerbations. We evaluated if repeated stress, induced by forced swimming, modulates lung mechanics, distal airway inflammation and extracellular matrix remodeling in guinea pigs with chronic allergic inflammation.

METHODS

Guinea pigs were submitted to 7 ovalbumin or saline aerosols (1-5 mg/ml during 4 weeks; OVA and SAL groups). Twenty-four hours after the 4th inhalation, guinea pigs were submitted to the stress protocol 5 times a week during 2 weeks (SAL-S and OVA-S groups). Seventy-two hours after the 7th inhalation, guinea pigs were anesthetized and mechanically ventilated. Resistance and elastance of the respiratory system were obtained at baseline and after ovalbumin challenge. Lungs were removed, and inflammatory and extracellular matrix remodeling of distal airways was assessed by morphometry. Adrenals were removed and weighed.

RESULTS

The relative adrenal weight was greater in stressed guinea pigs compared to non-stressed animals (p < 0.001). Repeated stress increased the percent elastance of the respiratory system after antigen challenge and eosinophils and lymphocytes in the OVA-S compared to the OVA group (p < 0.001, p = 0.003 and p < 0.001). Neither collagen nor elastic fiber contents were modified by stress in sensitized animals.

CONCLUSIONS

In this animal model, repeated stress amplified bronchoconstriction and inflammatory response in distal airways without interfering with extracellular matrix remodeling.

Immunology and the menstrual cycle

Sex and gender differences in disease prevalence, pathogenesis and modulation have been frequently reported. The menstrual cycle represents the opportunity to study the physiological effect of hormonal fluctuations in vivo on the immune function and chronic disease modulation. Reports on the effect of the cycle on immune cell numbers and activity fluctuations are scarce, but recent publications demonstrate an increasing interest in the subject. The menstrual cycle might affect immune cell numbers and modulate their activity throughout the 4-week cycle, as demonstrated in the case of regulatory T cells. The implications of these fluctuations are particularly relevant in the field of chronic diseases affecting women of reproductive age. In fact, baseline inflammation and immune cell activation in association with other mechanisms, such as regulation of receptor expression, modulation of muscular contraction and behavioral aspects might explain the menstrual-associated fluctuations described in chronic and acute diseases. In the following review the current knowledge about the modulatory effects of the menstrual cycle on both immune cells and systemic diseases, such as autoimmune diseases, asthma, diabetes, cardiac arrhythmia and schizophrenia, is reported. Most of these diseases display worsening of symptoms premenstrually or during menses due to physiologic effects on the target tissue mediated by progesterone and estrogen fluctuations and, thus, display paradigmatic changes potentially relevant to numerous other conditions.

Sex steroid receptors in human lung diseases

Several epidemiological studies have reported that gender differences exist in clinical and biological manifestations of human lung diseases. In particular, women are far more likely to develop both neoplastic and non-neoplastic lung diseases than men. This gender difference above suggests that sex steroid may be involved in the pathogenesis of various lung diseases. These sex steroids mediate their effects through sex steroid receptors including estrogen receptors (ER) i.e. ERα and ERβ progesterone receptors (PR) i.e. PR-A and PR-B and androgen receptors (ARs), all of which have been reported to be expressed in lung tissue. Therefore it becomes important to clarify the potential roles of sex steroid receptor in both neoplastic and non-neoplastic lung diseases toward improved treatment options for the patients. In this review, we summarized a number of studies in humans and experimental animals that have identified possible roles of sex steroids in respiratory physiology and pathology.

Effects of menopause on hepatic 11β-hydroxysteroid dehydrogenase type 1 activity and adrenal sensitivity to adrenocorticotropin in healthy non-obese women

Menopause is associated with central obesity, dyslipidemia, hypertension and insulin resistance, which are also shown in the patients with excess of glucocorticoids. However, the interaction of hypothalamic-pituitary-adrenal (HPA) axis activity and menopause has not been fully understood. In this study, 55 healthy non-obese women were recruited, and then divided into two groups, premenopausal group (n = 24) and postmenopausal group (n = 31). HPA axis function was evaluated by using dexamethasone suppression test (DST; 0.25 mg), and adrenocorticotrophic hormone (ACTH)-stimulation test. Moreover, 25 mg cortisone acetate test was applied to evaluate the hepatic 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity. We found that hepatic 11β-HSD1 activity and adrenal response to ACTH were increased in the postmenopausal group compared with the premenopausal group, whereas the negative feedback effect of dexamethasone did not show significant difference between pre- and postmenopausal women. These findings suggest that the adrenal sensitivity to ACTH and hepatic 11β-HSD1 activity are increased. The increased cortisol conversion and/or synthesis may be contributed to the dysmetabolic features in the postmenopausal women.

[Exacerbations of asthma--precipitating factors: drugs]

Asthmatic exacerbations are sometimes triggered by medications, primarily the non-steroidal anti-inflammatory agents (NSAIDS) and beta-blockers. Asthma attacks induced by NSAIDS occur rapidly and can be severe. Widal syndrome is a specific disease entity whose physiopathology remains incompletely explained. Asthma is characteristically severe and steroid dependent; desensitisation with aspirin has been proposed, but this remains controversial. Beta-blockers are contra-indicated in asthma; the β1 "cardioselectivity" of some agents is not absolute, disappearing at high doses and the "partial agonists" are not better tolerated. However, certain authors have called into question the harmful effect of beta-blockade in moderate and stable asthma. More studies are needed, but the current data suggest that in some cases beta-blockers may be safe but their use requires close supervision. Other molecules can pose problems in asthmatics (dipyridamole, synthetic sex hormones and certain excipients). On the whole, there has been little innovation concerning the hazard that drugs can pose for some asthmatics. The task for the future will be to specify the physiopathology of Widal syndrome, and to clarify the categories of patients in whom beta-blockers can be safely employed as the public health consequences of cardiovascular pathologies make this an important issue for lung specialists.

The role of female hormones on lung function in chronic lung diseases

Background

The prevalence, morbidity, and mortality of inflammatory lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF) are increasing in women. There is a dearth of data on the biological mechanisms to explain such observations. However, some large epidemiologic studies suggest that lung function fluctuates during the menstrual cycle in female patients with airways disease but not in women without disease, suggesting that circulating estradiol and progesterone may be involved in this process.

Discussion

In asthma, estradiol shuttles adaptive immunity towards the T_H2 phenotype while in smokers estrogens may be involved in the generation of toxic intermediate metabolites in the airways of female smokers, which may be relevant in COPD pathogenesis. In CF, estradiol has been demonstrated to up-regulate MUC5B gene in human airway epithelial cells and inhibit chloride secretion in the airways. Progesterone may augment airway inflammation.

Summary

Taken together, clinical and in-vivo data have demonstrated a sex-related difference in that females may be more susceptible to the pathogenesis of lung diseases. In this paper, we review the effect of female sex hormones in the context of these inflammatory airway diseases.

Single early prenatal lipopolysaccharide exposure prevents subsequent airway inflammation response in an experimental model of asthma

AIMS

There has been emerging interest in the prenatal determinants of respiratory disease. In utero factors have been reported to play a role in airway development, inflammation, and remodeling. Specifically, prenatal exposure to endotoxins might regulate tolerance to allergens later in life. The present study investigated whether prenatal lipopolysaccharide (LPS) administration alters subsequent offspring allergen-induced inflammatory response in adult rats.

MAIN METHODS

Pregnant Wistar rats were treated with LPS (100 μg/kg, i.p.) on gestation day 9.5 and their ovariectomized female offspring were sensitized and challenged with OVA later in adulthood. The bronchoalveolar lavage (BAL) fluid, peripheral blood, bone marrow leukocytes and passive cutaneous anaphylaxis were evaluated in these 75-day-old pups.

KEY FINDINGS

OVA sensitized pups of NaCl treated rats showed an increase of leucocytes in BAL after OVA challenge. This increase was attenuated, when mothers were exposed to a single LPS injection early in pregnancy. Thus, LPS prenatal treatment resulted in (1) lower increased total and differential (macrophages, neutrophils, eosinophils and lymphocytes) BAL cellularity count; (2) increased number of total, mononuclear and polymorphonuclear cells in the peripheral blood; and (3) no differences in bone marrow cellularity or passive cutaneous anaphylaxis.

SIGNIFICANCE

In conclusion, female pups treated prenatally with LPS presented an attenuated response to experimentally-induced asthma. We observed reduced immune cell migration from peripheral blood to the lungs, with no effect on the production of bone marrow cells or antibodies. It was suggested that inflammatory events such as exposure to LPS in early fetal life can attenuate allergic inflammation in the lung, which is a common symptom in asthma.

Female sex hormones mediate the allergic lung reaction by regulating the release of inflammatory mediators and the expression of lung E-selectin in rats

Background

Fluctuations of estradiol and progesterone levels caused by the menstrual cycle worsen asthma symptoms. Conflicting data are reported in literature regarding pro and anti-inflammatory properties of estradiol and progesterone.

Methods

Female Wistar rats were ovalbumin (OVA) sensitized 1 day after resection of the ovaries (OVx). Control group consisted of sensitized-rats with intact ovaries (Sham-OVx). Allergic challenge was performed by aerosol (OVA 1%, 15 min) two weeks later. Twenty four hours after challenge, BAL, bone marrow and total blood cells were counted. Lung tissues were used as explants, for expontaneous cytokine secretion in vitro or for immunostaining of E-selectin.

Results

We observed an exacerbated cell recruitment into the lungs of OVx rats, reduced blood leukocytes counting and increased the number of bone marrow cells. Estradiol-treated OVx allergic rats reduced, and those treated with progesterone increased, respectively, the number of cells in the BAL and bone marrow. Lungs of OVx allergic rats significantly increased the E-selectin expression, an effect prevented by estradiol but not by progesterone treatment. Systemically, estradiol treatment increased the number of peripheral blood leukocytes in OVx allergic rats when compared to non treated-OVx allergic rats. Cultured-BAL cells of OVx allergic rats released elevated amounts of LTB₄ and nitrites while bone marrow cells increased the release of TNF-α and nitrites. Estradiol treatment of OVx allergic rats was associated with a decreased release of TNF-α, IL-10, LTB₄ and nitrites by bone marrow cells incubates. In contrast, estradiol caused an increase in IL-10 and NO release by cultured-BAL cells. Progesterone significantly increased TNF- α by cultured BAL cells and bone marrow cells.

Conclusions

Data presented here suggest that upon hormonal oscillations the immune sensitization might trigger an allergic lung inflammation whose phenotype is under control of estradiol. Our data could contribute to the understanding of the protective role of estradiol in some cases of asthma symptoms in fertile ans post-menopausal women clinically observed.

Hormonal factors and respiratory health in women--a review

Sex hormones appear to play an important role in the lung health of women. This is, however, poorly understood and, in most aspects, poorly investigated; and the literature has been contradictory and confusing. This review presents recent research concerning the involvement of sex hormones in respiratory health of adult women, using the population surveys European Community Respiratory Health Survey and Respiratory Health in Northern Europe. Respiratory health varied substantially according to hormonal and metabolic conditions. First, menopause was associated with lower lung function and more respiratory symptoms, especially among lean women. Second, hormonal replacement therapy (HRT) was associated with increased risk for asthma and wheeze; also, this association was particularly strong among lean women. Third, women with irregular menstruations in fertile age had more asthma, particularly allergic asthma, and reduced lung function, independently of body mass index (BMI) and physical activity. The findings were consistent across cultural and geographical borders. Our studies revealed that considering interplay between hormonal and metabolic factors is a clue to understand the effects of female sex hormones on the airways. A BMI of around 24-25 kg/m(2) appeared to be optimal; women with this BMI had no increase in respiratory health problems when reaching menopause or using HRT, and women in fertile age with this BMI had optimal lung function independently of menstrual status. In conclusion, female sex hormones appear to play a most important role for lung health in women. Further research on effects of sex hormones on the airways should take into account potential interplay with metabolic factors.

Hormonal influences on lung function and response to environmental agents: lessons from animal models of respiratory disease

Numerous studies in humans and experimental animals have identified considerable sex differences in respiratory physiology and in the response of the lung to environmental agents. These differences appear to be mediated, at least in part, by sex hormones and their nuclear receptors. Moreover, animal models are increasingly used to study pathogenic mechanisms and test potential therapies for a variety of human lung diseases, many of which appear to be influenced by sex and sex hormones. In this article, data are summarized from studies of lung function and disease in which sex differences have been observed. Specific attention is paid to animal models of acute lung injury, nonallergic and allergic lung inflammation, and lung fibrosis. It is anticipated that continued investigation of the role of sex and sex hormones in animal models will provide valuable insight into the pathogenesis and potential treatments for a variety of acute and chronic human lung diseases.

Estrogen receptor-alpha as a drug target candidate for preventing lung inflammation

Accumulating evidence shows that estrogens are protective factors in inflammatory lung diseases and are involved in the gender-related incidence of these pathologies. The aim of this study was to identify which estrogen receptor (ER), ER-alpha and/or ER beta, mediates hormone antiinflammatory effects in lung and how gender or aging modify this effect. Acute lung inflammation in wild type, ER alpha or ER beta knockout animals was induced by pleural injection of carrageenan; female mice were used and sham operated, ovariectomized, or ovariectomized and treated with 17beta-estradiol (E(2)) before carrageenan. Our data show that ER alpha, and not ER beta, mediates E(2)-induced reduction of the inflammatory response. By real-time PCR and immunohistochemistry assays, we demonstrate ER alpha expression in the resident and infiltrated inflammatory cells of the lung, in which ER beta could not be detected. In these cells, E(2)-mediated reduction in the expression of inflammatory mediators was also due to ER alpha. In parallel, we observed that female mice were more prone to inflammation as compared with males, suggesting a gender-related difference in lung susceptibility to inflammatory stimuli, whereas the effect of E(2) was similar in the two sexes. Interestingly, aging results in a strong increase in the inflammatory response in both sexes and in the disruption E(2)/ER alpha signaling pathway. In conclusion, our data reveal that E(2) is able to regulate lung inflammation in a gender-unrelated, age-restricted manner. The specific involvement of ER alpha in hormone action opens new ways to identify drug targets that limit the inflammatory component of lung pathologies.