Aspirin-exacerbated respiratory disease is associated with variants in filaggrin, epithelial integrity, and cellular interactions

Background

Previous studies have determined that up to 6% of patients with aspirin-exacerbated respiratory disease (AERD) have family history of AERD, indicating a possible link with genetic polymorphisms. However, whole exome sequencing (WES) studies of such associations are currently lacking.

Objectives

We sought to examine whether WES can identify pathogenic variants associated with AERD.

Methods

Diagnoses of AERD were confirmed in patients with nasal polyps and asthma. WES was performed using an Illumina sequencing platform. Human Phenotype Ontology terms were used to define the patients' phenotypes. Exomiser was used to annotate, filter, and prioritize possible disease-causing genetic variants.

Results

Of 39 patients with AERD, 41% reported a family history of asthma and 5% reported a family history of AERD. Pathogenic exome variants in the filaggrin gene (FLG) were found in 2 patients (5%). Other variants not known to be pathogenic were detected in an additional 16 patients (41%) in genes related to epithelial integrity and cellular interactions, including genes encoding desmoglein 3 (DSG3), dynein axonemal heavy chain 9 (DNAH9), collagen type VII alpha 1 chain (COL7A1), collagen type XVII alpha 1 chain (COL17A1), chromodomain helicase DNA binding protein-7 (CHD7), TSC complex subunit 2/tuberous sclerosis-2 protein (TSC2), P-selectin (SELP), and platelet-derived growth factor receptor-alpha (PDGFRA).

Conclusion

WES identified a monogenic susceptibility to AERD in 5% of patients with FLG pathogenic variants. Other variants not previously identified as pathogenic were found in genes relevant to epithelial integrity and cellular interactions and may further reveal genetic factors that contribute to this condition.

Progestogen Hypersensitivity

Progestogen hypersensitivity (PH) is a heterogeneous disease characterized by diverse cutaneous manifestations, bronchospasm, and/or anaphylaxis. Possible triggers include ovarian progesterone and exogenous progestogens. The timing of symptoms is critical to diagnose PH: during the luteal phase of the menstrual cycle for the endogenous form and after exposure to progestins for exogenous PH. Diagnostic modalities such as progesterone skin testing have low sensitivity and specificity for PH. When exogenous PH is suspected, the allergist should consider a progestogen challenge. Treatment strategies should be tailored for each patient, including symptom-directed therapies, ovulation suppression, and progesterone desensitization. Future studies should explore the mechanisms of PH, validation of diagnostic criteria, and standardization of treatment strategies.

Endogenous inhibitory mechanisms in asthma

Endogenous inhibitory mechanisms promote resolution of inflammation, enhance tissue repair and integrity, and promote homeostasis in the lung. These mechanisms include steroid hormones, regulatory T cells, IL-10, prostaglandin E2, prostaglandin I2, lipoxins, resolvins, protectins, maresins, glucagon-like peptide-1 receptor, adrenomedullin, nitric oxide, and carbon monoxide. Here we review the most recent literature regarding these endogenous inhibitory mechanisms in asthma, which remain a promising target for the prevention and treatment of asthma.

Sex differences in a murine model of asthma are time and tissue compartment dependent

CONCLUSION

Sexual dimorphism in lung inflammation is both time and tissue compartment dependent. Spatiotemporal variability in sex differences in a murine model of asthma must be accounted for when planning experiments to model the sex bias in allergic inflammation.

Global disparities in availability of epinephrine auto-injectors

Background

Anaphylaxis is the most severe clinical presentation of acute systemic allergic reactions and can cause death. Given the prevalence of anaphylaxis within healthcare systems, it is a high priority public health issue. However, management of anaphylaxis - both acute and preventative - varies by region.

Methods

The World Allergy Organization (WAO) Anaphylaxis Committee and the WAO Junior Members Steering Group undertook a global online survey to evaluate local practice in the diagnosis and management of anaphylaxis across regions.

Results

Responses were received from WAO members in 66 countries. While intramuscular epinephrine (adrenaline) is first-line treatment for anaphylaxis, some countries continue to recommend alternative routes in contrast to guidelines. Epinephrine auto-injector (EAI) devices, prescribed to individuals at ongoing risk of anaphylaxis in the community setting, are only available in 60% of countries surveyed, mainly in high-income countries. Many countries in South America, Africa/Middle-East and Asian-Pacific regions do not have EAI available, or depend on individual importation. In countries where EAIs are commercially available, national policies regarding the availability of EAIs in public settings are limited to few countries (16%). There is no consensus regarding the time patients should be observed following emergency treatment of anaphylaxis.

Conclusion

This survey provides a global snapshot view of the current management of anaphylaxis, and highlights key unmet needs including the global availability of epinephrine for self-injection as a key component of anaphylaxis management.

Hypersensitivity reactions to biologics used in the treatment of allergic diseases: clinical features, diagnosis and management

Several monoclonal antibodies have been approved by the Food and Drug Administration (FDA) to treat allergic disorders, including omalizumab, dupilumab, mepolizumab, reslizumab, benralizumab, tralokinumab and tezepelumab, and their indications continue to expand. Although the risks associated with these agents are overall low, hypersensitivity reactions have been described and are reported more frequently with increased use. We provide a comprehensive review of clinical features, diagnosis and management of hypersensitivity reactions attributed to these agents. We aim to provide useful information for the clinician managing hypersensitivity reactions to these monoclonal antibodies, as well as highlight the need for future research to address specific gaps in knowledge.

Biomarkers of cellular senescence in idiopathic pulmonary fibrosis

BACKGROUND

Cellular senescence is a cell fate in response to diverse forms of age-related damage and stress that has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). The associations between circulating levels of candidate senescence biomarkers and disease outcomes have not been specifically studied in IPF. In this study we assessed the circulating levels of candidate senescence biomarkers in individuals affected by IPF and controls and evaluated their ability to predict disease outcomes.

METHODS

We measured the plasma concentrations of 32 proteins associated with senescence in Lung Tissue Research Consortium participants and studied their relationship with the diagnosis of IPF, parameters of pulmonary and physical function, health-related quality of life, mortality, and lung tissue expression of P16, a prototypical marker of cellular senescence. A machine learning approach was used to evaluate the ability of combinatorial biomarker signatures to predict disease outcomes.

RESULTS

The circulating levels of several senescence biomarkers were significantly elevated in persons affected by IPF compared to controls. A subset of biomarkers accurately classified participants as having or not having the disease and was significantly correlated with measures of pulmonary function, health-related quality of life and, to an extent, physical function. An exploratory analysis revealed senescence biomarkers were also associated with mortality in IPF participants. Finally, the plasma concentrations of several biomarkers were associated with their expression levels in lung tissue as well as the expression of P16.

CONCLUSIONS

Our results suggest that circulating levels of candidate senescence biomarkers are informative of disease status, pulmonary and physical function, and health-related quality of life. Additional studies are needed to validate the combinatorial biomarkers signatures that emerged using a machine learning approach.

Paired Indoor and Outdoor Nitrogen Dioxide Associated With Childhood Asthma Outcomes in a Mixed Rural-Urban Setting: A Feasibility Study

INTRODUCTION

Nitrogen dioxide (NO₂) is known to be a trigger for asthma exacerbation. However, little is known about the role of seasonal variation in indoor and outdoor NO₂ levels in childhood asthma in a mixed rural-urban setting of North America.

METHODS

This prospective cohort study, as a feasibility study, included 62 families with children (5-17 years) that had diagnosed persistent asthma residing in Olmsted County, Minnesota. Indoor and outdoor NO₂ concentrations were measured using passive air samples over 2 weeks in winter and 2 weeks in summer. We assessed seasonal variation in NO₂ levels in urban and rural residential areas and the association with asthma control status collected from participants' asthma diaries during the study period.

RESULTS

Outdoor NO₂ levels were lower (median: 2.4 parts per billion (ppb) in summer, 3.9 ppb in winter) than the Environmental Protection Agency (EPA) annual standard (53 ppb). In winter, a higher level of outdoor NO₂ was significantly associated with urban residential living area (P = .014) and lower socioeconomic status (SES) (P = .027). For both seasons, indoor NO₂ was significantly higher (P < .05) in rural versus urban areas and in homes with gas versus electric stoves (P < .05). Asthma control status was not associated with level of indoor or outdoor NO₂ in this cohort.

CONCLUSIONS

NO₂ levels were low in this mixed rural-urban community and not associated with asthma control status in this small feasibility study. Further research with a larger sample size is warranted for defining a lower threshold of NO₂ concentration with health effect on asthma in mixed rural-urban settings.

Asthma in pregnancy

Background: Asthma is a frequent and potentially life-threatening disease that complicates many pregnancies. There are extensive data with regard to the diagnosis and treatment of asthma during pregnancy. Medical providers require an up-to-date summary of the critical aspects of asthma management during pregnancy. Objective: This review aimed to summarize the available data from clinical trials, cohort studies, expert opinions, and guideline recommendations with regard to asthma in pregnancy. Methods: A search through PubMed was conducted by using keywords previously mentioned and MeSH (Medical Subject Headings) terminology. Clinical trials, observational studies, expert opinions, guidelines, and other reviews were included. The quality of the studies was assessed, and data were extracted and summarized. Results: Asthma worsens in ∼40% of pregnant women, which can be associated with maternal and fetal complications. Physiologic changes in the respiratory, cardiovascular, and immune systems during pregnancy play a critical role in the manifestations of asthma. The diagnosis and the treatment of asthma are similar to that of patients who are not pregnant. Nonetheless, concern for fetal malformations, preterm birth, and low birth weight must be considered when managing pregnant patients with asthma. Importantly, cornerstones of the pharmacotherapy of asthma seem to be safe during pregnancy. Conclusion: Asthma in pregnancy is associated with adverse outcomes. Roadblocks to management include associated comorbidities, medication nonadherence, atopy, lack of education, and smoking habits. These need to be acknowledged and addressed for successful asthma management during pregnancy.

Alpha-T-catenin is expressed in peripheral nerves as a constituent of Schwann cell adherens junctions

The adherens junction component, alpha-T-catenin (αTcat) is an established contributor to cardiomyocyte junction structure and function, but recent genomic studies link CTNNA3 polymorphisms to diseases with no clear cardiac underpinning, including asthma, autism and multiple sclerosis, suggesting causal contributions from a different cell-type. We show Ctnna3 mRNA is highly expressed in peripheral nerves (e.g. vagus and sciatic), where αTcat protein enriches at paranodes and myelin incisure adherens junctions of Schwann cells. We validate αTcat immunodetection specificity using a new Ctnna3-knock-out fluorescence reporter mouse line yet find no obvious Schwann cell loss-of-function morphology at the light microscopic level. CTNNA3/Ctnna3 mRNA is also abundantly detected in oligodendrocytes of the central nervous system via public databases, supporting a general role for αTcat in these unique cell-cell junctions. These data suggest that the wide range of diseases linked to CTNNA3 may be through its role in maintaining neuroglial functions of central and peripheral nervous systems. This article has a corresponding First Person interview with the co-first authors of the paper.

Safety of Biologics for Atopic Diseases During Pregnancy

The high prevalence of atopic diseases in women of childbearing age reveals the need to determine the safety of biologics during pregnancy. This review summarizes the effects of 7 Food and Drug Administration-approved biologics (omalizumab, mepolizumab, reslizumab, benralizumab, dupilumab, tezepelumab, and tralokinumab) on maternal and fetal outcomes. For this purpose, we reviewed English-language publications to investigate whether the use of biologics for atopic diseases during pregnancy increased the risk of preterm delivery, stillbirth, low birth weight, or congenital malformations. Most publications found were case reports, case series, or observational studies reporting outcomes in a total of 313 pregnancies. No randomized controlled studies were identified. We found that biologics do not seem to influence maternal or fetal outcomes. Indeed, worsening of the underlying atopic disease during pregnancy appears to be more detrimental to the viability of the pregnancy. Given the small sample size and scarcity of studies, future research should include prospective studies with comparable control groups without exposure to biologics and multicenter registries for long-term follow-up.

Hormonal Effects on Asthma, Rhinitis, and Eczema

Hormones significantly influence the pathogenesis of asthma, rhinitis, and eczema. This review aims to summarize relevant clinical considerations for practicing allergists and immunologists. The first section reviews the effects of sex hormones: estrogen, progesterone, and testosterone. The second concerns insulin production in the context of type 1 and type 2 diabetes. The third concludes with a discussion of thyroid and adrenal pathology in relationship to asthma, rhinitis, and eczema.

Predictors of seroconversion after coronavirus disease 2019 vaccination

Background

Vaccine nonresponse during the coronavirus disease 2019 (COVID-19) pandemic has considerable individual and societal risks.

Objective

To investigate the clinical characteristics of patients with lack of seroconversion after vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods

Demographic and clinical data were collected from 805 patients who had validated antibody assays against the SARS-CoV-2 spike protein at least 14 days after completion of their COVID-19 vaccination. Clinical characteristics from patients with a negative (< 0.4 U/mL) antibody response were assessed and summarized.

Results

A total of 622 (77.3%) patients attained seroconversion as defined by a titer of greater than or equal to 0.4 U/mL, whereas 183 out of 805 (22.7%) patients exhibited no seroconversion after vaccination against SARS-CoV-2. Univariately, older age (P = .02) and male sex were associated with a lower likelihood of seroconversion (P = .003). Therapy with immunosuppressive drugs was noted in 93 (50.8%) of seronegative patients with most (n = 83/93, 89.2%) receiving ongoing immunosuppressive therapy at the time of vaccination. Among the 134 (73.2%) seronegative patients with immunodeficiency, 110 (82.1%) had primary immunodeficiency. Cancer (n = 128, 69.9%), B cell depletion therapy (n = 90/115, 78.3%), and immunosuppressant steroid use (n = 71/93 on immunosuppressants, 76.3%) were the other common characteristics among the vaccine nonresponders. More importantly, our study did not evaluate the actual efficacy of COVID-19 vaccination.

Conclusion

Vaccine responses vary by age and sex, with men showing lower rates of seroconversion as compared with women. Primary immunodeficiency along with active malignancy and ongoing immunosuppression with steroids or B cell depletion therapy appeared to be the most common characteristics for those with a lack of vaccine seroconversion after COVID-19 vaccination.

Utility and futility of skin testing to address concerns surrounding messenger RNA coronavirus disease 2019 vaccine reactions

BACKGROUND

The mechanism of coronavirus disease 2019 (COVID-19) vaccine hypersensitivity reactions is unknown. COVID-19 vaccine excipient skin testing has been used in evaluation of these reactions, but its utility in predicting subsequent COVID-19 vaccine tolerance is also unknown.

OBJECTIVE

To evaluate the utility of COVID-19 vaccine and vaccine excipient skin testing in both patients with an allergic reaction to their first messenger RNA COVID-19 vaccine dose and patients with a history of polyethylene glycol allergy who have not yet received a COVID-19 vaccine dose.

METHODS

In this multicenter, retrospective review, COVID-19 vaccine and vaccine excipient skin testing was performed in patients referred to 1 of 3 large tertiary academic institutions. Patient medical records were reviewed after skin testing to determine subsequent COVID-19 vaccine tolerance.

RESULTS

A total of 129 patients underwent skin testing, in whom 12 patients (9.3%) had positive results. There were 101 patients who received a COVID-19 vaccine after the skin testing, which was tolerated in 90 patients (89.1%) with no allergic symptoms, including 5 of 6 patients with positive skin testing results who received a COVID-19 vaccine after the skin testing. The remaining 11 patients experienced minor allergic symptoms after COVID-19 vaccination, none of whom required treatment beyond antihistamines.

CONCLUSION

The low positivity rate of COVID-19 vaccine excipient skin testing and high rate of subsequent COVID-19 vaccine tolerance suggest a low utility of this method in evaluation of COVID-19 vaccine hypersensitivity reactions. Focus should shift to the use of existing vaccine allergy practice parameters, with consideration of graded dosing when necessary. On the basis of these results, strict avoidance of subsequent COVID-19 vaccination should be discouraged.

Delayed systemic urticarial reactions following mRNA COVID-19 vaccination

Background: As the vaccination campaign in response to the coronavirus disease 2019 (COVID-19) pandemic continues, concerns with regard to adverse reactions to the vaccine remain. Although immediate hypersensitivity reactions have received much attention, delayed systemic urticarial reactions after vaccination can occur. Objective: To describe the clinical presentation, vaccine excipient skin testing results, and outcomes of subsequent COVID-19 vaccination in patients who experienced delayed systemic urticarial reactions after messenger RNA (mRNA) COVID-19 vaccination. Methods: This was a retrospective case series of 12 patients referred to the Mayo Clinics in Rochester, Minnesota, and Jacksonville, Florida, between January 19, 2021, and April 30, 2021, for evaluation of delayed systemic urticarial reactions after mRNA COVID-19 vaccination. Demographics, medical and allergic history, reaction details, vaccine excipient skin testing results (when performed), and the outcome after subsequent vaccination were collected for each patient. Results: The mean age of the patients was 52 years, all were white, and 9 (75%) were women. Half of the patients had a history of drug allergy, and one had a history of chronic spontaneous urticaria. Seven patients reacted to the Pfizer-BioNTech vaccine and five reacted to the Moderna vaccine. Seven patients developed symptoms between 8 and 24 hours after vaccination. Nine patients required antihistamines for treatment. The median time to symptom resolution was 4 days. Nine patients underwent allergist-directed COVID-19 vaccine excipient skin testing, all of which were negative. Ten patients chose to receive their next mRNA COVID-19 vaccine dose, and four patients experienced recurrent delayed urticaria. Conclusion: Delayed systemic urticarial reactions after mRNA COVID-19 vaccination were not life-threatening, could be treated with antihistamines, and were not predicted with vaccine excipient skin testing. They were not a contraindication to subsequent vaccination, although patients should be counseled with regard to the possibility of recurrence.

State-of-the-art beta-adrenoreceptor agonists for the treatment of asthma

INTRODUCTION

Asthma, a heterogeneous disease, is characterized by chronic airway inflammation and hyperreactivity. β₂-adrenoreceptor agonists (β₂-agonists) remain pivotal for asthma management. Short-acting β₂-agonists (SABAs) result in rapid symptomatic alleviation and bronchospasm prevention. Patients experience significant clinical benefits from therapy with long-acting β₂-agonists (LABAs) with efficacy to bronchodilate, and prolonged lung function betterment. Recently discovered β₂-agonists with longer half-lives offer once-daily dosing.

AREAS COVERED

The authors provide a thorough review of the pharmacokinetics, pharmacodynamics, efficacy, tolerability, classification, and safety of β₂-agonists through an in-depth review of current literature using these databases: U.S. National Institutes of Health's National Library of Medicine (NIH/NLM), PubMed Central, and NLM clinical trials.

EXPERT OPINION

β₂- agonists act primarily on airway smooth muscle cells and are quintessential for adequate asthma management. Given their pharmacodynamic and pharmacokinetic properties, SABAs are used as rescue medication. Notably, the current Global Initiative for Asthma (GINA) strategy document recommends using LABA/inhaled corticosteroid combinations both as a daily controller and as a rescue medication. Clinicians should assess this new treatment plan on a per-case basis, making sure to evaluate inhaler adherence and treat modifiable risk factors. The development of next-generation β₂- agonists is an exciting research area that could significantly improve patients' adherence to treatment regimens and, consequently, asthma control and quality of life.

Outcomes among patients with COVID-19 and asthma: A systematic review and meta-analysis

Background: It remains unclear if asthma is a risk factor associated with worse outcomes among patients with coronavirus disease 2019 (COVID-19). Methods: We performed a comprehensive database search for studies published from January 1, 2019, to October 2, 2020. We included studies that evaluated outcomes among patients with COVID-19 and underlying asthma. Outcomes of interest included the need for hospitalization, length of hospitalization, intensive care unit (ICU) admission, and death. The meta-analysis was conducted by using random-effects methodology. Results: A total of 389 studies were identified through data base searches. After abstract and full-text screening, 16 observational studies with 92,275 patients were included in the analysis. Of the 16 studies, 15 were retrospective and 1 was a prospective cohort study. The average age was 39.6 years, with 48% female patients. Six of the studies included pediatric patients, and one of these studies only evaluated pediatric patients. One study only evaluated pregnant patients. Among patients with COVID-19, the presence of asthma was not associated with any significant increase in risk of hospitalization (odds ratio [OR] 1.46 [95% confidence interval {CI}, 0.29-7.28]), length of hospitalization (1.59 days [-0.55 to 3.74]), ICU admission (OR 1.65 [95% CI, 0.56-4.17]), or death (OR 0.73 [95% CI, 0.38-1.40]). The overall risk of bias of the included studies was high. Conclusion: Among the patients with COVID-19, asthma did not seem to significantly increase the risk of hospitalization, length of hospitalization, ICU admission, or death.

Sex, Cells, and Asthma

There are marked sex differences in asthma prevalence and severity. Sex hormones play a central role in these sex biases and directly interact with multiple key cells involved in the pathogenesis of asthma. Here we review the known effects of estrogen, progesterone, and testosterone on airway epithelial cells, airway smooth muscle cells, the mononuclear phagocyte system, innate lymphoid cells, eosinophils, mast cells, T cells, and B cells, all in the context of asthma. Furthermore, we explore unresolved clinical questions, such as the role of sex hormones in the link between asthma and obesity.

Senolytics reduce coronavirus-related mortality in old mice

Cellular senescence is a state elicited in response to stress signals and is associated with a damaging secretory phenotype. The number of senescent cells increases with advanced age and this in turn drives age-related diseases. Camell et al. show that senescent cells have an amplified inflammatory response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (see the Perspective by Cox and Lord). This response is communicated to nonsenescent cells, suppressing viral defense mechanisms and increasing the expression of viral entry proteins. In old mice infected with a SARS-CoV-2–related virus, treatment with senolytics to reduce the senolytic cell burden reduced mortality and increased antiviral antibodies.

Science, abe4832, this issue p. eabe4832; see also abi4474, p. 281

INTRODUCTION

The COVID-19 pandemic revealed enhanced vulnerability of the elderly and chronically ill to adverse outcomes upon severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Senescence is a cell fate elicited by cellular stress that results in changes in gene expression, morphology, metabolism, and resistance to apoptosis. Senescent cells (SnCs) secrete pro-inflammatory factors, called the senescence-associated secretory phenotype (SASP). SnCs accumulate with age and drive chronic inflammation. In human cells and tissues and using a new infection paradigm, we asked whether SnCs are a cause of adverse outcomes of infection with aging. This is relevant because SnCs can be selectively eliminated in vivo with a new class of therapeutics called senolytics, potentially affording a new approach to treat COVID-19.

RATIONALE

We hypothesized that SnCs, because of their pro-inflammatory SASP, might have a heightened response to pathogen-associated molecular pattern (PAMP) factors, resulting in increased risk of cytokine storm and multi-organ failure. To test this, we treated senescent and nonsenescent human cells with the PAMPs lipopolysaccharide (LPS) and SARS-CoV-2 spike protein (S1) and measured the SASP and its effect on non-SnCs. Similarly, old and progeroid mice were challenged with LPS, and we measured the SASP. Previously, we created a “normal microbial experience” (NME) for mice by transmitting environmental pathogens to specified-pathogen–free (SPF) mice through exposure to pet store mice or their bedding. The first pathogen transferred was mouse hepatitis virus (MHV), a β-coronavirus closely related to SARS-CoV-2. NME rapidly killed aged SPF mice known to have an increased burden of SnCs compared with young SPF mice, which survive NME. This afforded an experimental paradigm to test whether senolytics blunt adverse outcomes in β-coronavirus infection.

RESULTS

Human endothelial SnCs became hyperinflammatory in response to challenge with LPS and S1, relative to non-SnCs. The PAMP-elicited secretome of SnCs caused increased expression of viral entry proteins and reduced expression of antiviral genes in nonsenescent human endothelial and lung epithelial cells, and the proximity of these events was established in human lung biopsies. Treatment of old mice with LPS significantly increased SASP expression in several organs relative to young mice, confirming our hypothesis in vivo. Similarly, old mice exposed to NME displayed a significant multi-organ increase in SnCs and the SASP, impaired immune response to MHV, and 100% mortality, whereas inoculation with antibodies against MHV before NME afforded complete rescue of mortality. Treating old mice with the senolytic fisetin, which selectively eliminates SnCs after NME reduced mortality by 50%, reduced expression of inflammatory proteins in serum and tissue and improved the immune response. This was confirmed with a second senolytic regimen, Dasatinib plus Quercetin, as well as genetic ablation of SnCs in aged mice, establishing SnCs as a cause of adverse outcomes in aged organisms exposed to a new viral pathogen.

CONCLUSION

SnCs amplify susceptibility to COVID-19 and pathogen-induced hyperinflammation. Reducing SnC burden in aged mice reduces mortality after pathogen exposure, including a β-coronavirus. Our findings strongly support the Geroscience hypothesis that therapeutically targeting fundamental aging mechanisms improves resilience in the elderly, with alleviation of morbidity and mortality due to pathogenic stress. This suggests that senolytics might protect others vulnerable to adverse COVID-19 outcomes in whom increased SnCs occur (such as in obesity or numerous chronic diseases).

The COVID-19 pandemic has revealed the pronounced vulnerability of the elderly and chronically ill to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–induced morbidity and mortality. Cellular senescence contributes to inflammation, multiple chronic diseases, and age-related dysfunction, but effects on responses to viral infection are unclear. Here, we demonstrate that senescent cells (SnCs) become hyper-inflammatory in response to pathogen-associated molecular patterns (PAMPs), including SARS-CoV-2 spike protein-1, increasing expression of viral entry proteins and reducing antiviral gene expression in non-SnCs through a paracrine mechanism. Old mice acutely infected with pathogens that included a SARS-CoV-2–related mouse β-coronavirus experienced increased senescence and inflammation, with nearly 100% mortality. Targeting SnCs by using senolytic drugs before or after pathogen exposure significantly reduced mortality, cellular senescence, and inflammatory markers and increased antiviral antibodies. Thus, reducing the SnC burden in diseased or aged individuals should enhance resilience and reduce mortality after viral infection, including that of SARS-CoV-2.

Metabolism of Epithelial Cells in Health and Allergic Disease: Collegium Internationale Allergologicum Update 2021

Concomitant dramatic increase in prevalence of allergic and metabolic diseases is part of a modern epidemic afflicting technologically advanced societies. While clinical evidence points to clear associations between various metabolic factors and atopic disease, there is still a very limited understanding of the mechanisms that link the two. Dysregulation of central metabolism in metabolic syndrome, obesity, diabetes, and dyslipidemia has a systemic impact on multiple tissues and organs, including cells of the epithelial barrier. While much of epithelial research in allergy has focused on the immune-driven processes, a growing number of recent studies have begun to elucidate the role of metabolic components of disease. This review will revisit clinical evidence for the relationship between metabolic and allergic diseases, as well as discuss potential mechanisms driving metabolic dysfunction of the epithelial barrier. Among them, novel studies highlight links between dysregulation of the insulin pathway, glucose metabolism, and loss of epithelial differentiation in asthma. Studies of mitochondrial structure and bioenergetics in lean and obese asthmatic phenotypes recently came to light to provide a novel framework linking changes in tricarboxylic acid cycle and oxidative phosphorylation with arginine metabolism and nitric oxide bioavailability. New research established connections between arachidonate metabolism, autophagy, and airway disease, as well as systemic dyslipidemia in atopic dermatitis and ceramide changes in the epidermis. Taken together, studies of metabolism have a great potential to open doors to a new class of therapeutic strategies, better characterization of disease endotypes, as well as enable a systems biology approach to mechanisms of allergic disease.

Passive siRNA transfection method for gene knockdown in air-liquid interface airway epithelial cell cultures

Differentiation of human bronchial epithelial cells (HBEs) in air-liquid interface (ALI) cultures recapitulates organotypic modeling of the in vivo environment. Although ALI cultures are invaluable for studying the respiratory epithelial barrier, loss-of-function studies are limited by potentially cytotoxic reagents in classical transfection methods, the length of the differentiation protocol, and the number of primary epithelial cell passages. Here, we present the efficacy and use of a simple method for small interfering RNA (siRNA) transfection of normal HBEs (NHBEs) in ALI cultures that does not require potentially cytotoxic transfection reagents and does not detrimentally alter the physiology or morphology of NHBEs during the differentiation process. This transfection protocol introduces a reproducible and efficient method for loss-of-function studies in HBE ALI cultures that can be leveraged for modeling the respiratory system and airway diseases.

Estrogen regulates the expression of SARS-CoV-2 receptor ACE2 in differentiated airway epithelial cells

There is marked sexual dimorphism in the current coronavirus disease 2019 (COVID-19) pandemic. Here we report that estrogen can regulate the expression of angiotensin-converting enzyme 2 (ACE2), a key component for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cell entry, in differentiated airway epithelial cells. Further studies are required to elucidate the mechanisms by which sex steroids regulate SARS-CoV-2 infectivity.

Immunobiologic treatments for severe asthma, atopic dermatitis, and chronic urticaria

Immunobiologic agents are an important therapeutic alternative for severe asthma, atopic dermatitis, and chronic urticaria. In this article, we reviewed the most relevant studies that addressed the use of anti-immunoglobulin E (omalizumab), anti-IL-5 (mepolizumab, reslizumab, and benralizumab), and anti-IL-4/IL-13 (dupilumab) treatments for these allergic diseases. In addition, we discussed emerging immunobiologic therapies, such as tezepelumab.

Gene expression of TMEM178, which encodes a negative regulator of NFATc1, decreases with the progression of asthma severity

In two independent microarray studies involving primary airway epithelial cells, the relative gene expression of TMEM178 decreases with the progression of asthma severity. Our manuscript creates a paradigm for future studies dissecting the role of Tmem178 in the pathogenesis of severe asthma.

Induced hyperglycemia promotes sensitization and exacerbates allergic inflammation in a mouse model of asthma

Glucose is a key source of energy in systemic and cellular metabolism and has known pro-inflammatory properties. It has recently been acknowledged that associations exist between metabolic disorders (diabetes, insulin resistance, obesity), asthma and other allergic diseases. As the prevalence of both metabolic and allergic disorders increases, it is important to understand how metabolism can influence the development of allergy. First, we injected fasted wild type Balbc/J mice intraperitoneally (i.p.) with 2g/kg dextrose (standard hyperglycemic challenge) to test whether hyperglycemia promotes inflammation favoring antigen sensitization. Within one hour of injection, we detected a rapid increase in blood glucose levels (up to 130 mg/dL) followed by an increase in Il1β, Tslp, Cxcl9, and Siglec5 gene expression in the peritoneal tissue compared to vehicle controls. Within 2 hours post injection, IL-1β protein was detected in peritoneal cellular infiltrate. In order to determine whether glucose-induced inflammation promotes allergic response, we sensitized mice by i.p. to chicken egg ovalbumin (OVA) using either alum (standard adjuvant), dextrose or vehicle control. Both alum/OVA and dextrose/OVA mounted lung allergic inflammation in response to inhaled OVA antigen. Dextrose/OVA mice had OVA-specific IgE production similar to alum/OVA group, demonstrating ability to promote sensitization. Remarkably, total cellular infiltrates, bronchoalveolar lavage eosinophils, lung expression of IL-4, IL-13 and IL-33 in dextrose-sensitized mice were equal or surpassing allergic inflammatory responses in mice given standard adjuvant. These results demonstrate a potentially critical role for glucose in promotion of allergy.

Metformin Targets Mitochondrial Electron Transport to Reduce Air-Pollution-Induced Thrombosis

Urban particulate matter air pollution induces the release of pro-inflammatory cytokines including interleukin-6 (IL-6) from alveolar macrophages, resulting in an increase in thrombosis. Here, we report that metformin provides protection in this murine model. Treatment of mice with metformin or exposure of murine or human alveolar macrophages to metformin prevented the particulate matter-induced generation of complex III mitochondrial reactive oxygen species, which were necessary for the opening of calcium release-activated channels (CRAC) and release of IL-6. Targeted genetic deletion of electron transport or CRAC channels in alveolar macrophages in mice prevented particulate matter-induced acceleration of arterial thrombosis. These findings suggest metformin as a potential therapy to prevent some of the premature deaths attributable to air pollution exposure worldwide.

αT-catenin: A developmentally dispensable, disease-linked member of the α-catenin family

α-Catenins are actin-filament binding proteins and critical subunits of the cadherin-catenin cell-cell adhesive complex. They are found in nominally-defined epithelial (E), neural (N), and testis (T) forms transcribed from three distinct genes. While most of α-catenin research has focused on the developmentally essential founding member, αE-catenin, this review discusses recent studies on αT-catenin (CTNNA3), a developmentally dispensable isoform that is emerging as relevant to cardiac, allergic and neurological diseases.

Shaping eosinophil identity in the tissue contexts of development, homeostasis, and disease

Eosinophils play homeostatic roles in different tissues and are found in several organs at a homeostatic baseline, though their tissue numbers increase significantly in development and disease. The morphological, phenotypical, and functional plasticity of recruited eosinophils are influenced by the dynamic tissue microenvironment changes between homeostatic, morphogenetic, and disease states. Activity of the epithelial-mesenchymal interface, extracellular matrix, hormonal inputs, metabolic state of the environment, as well as epithelial and mesenchymal-derived innate cytokines and growth factors all have the potential to regulate the attraction, retention, in situ hematopoiesis, phenotype, and function of eosinophils. This review examines the reciprocal relationship between eosinophils and such tissue factors, specifically addressing: (1) tissue microenvironments associated with the presence and activity of eosinophils; (2) non-immune tissue ligands regulatory for eosinophil accumulation, hematopoiesis, phenotype, and function (with an emphasis on the extracellular matrix and epithelial-mesenchymal interface); (3) the contribution of eosinophils to regulating tissue biology; (4) eosinophil phenotypic heterogeneity in different tissue microenvironments, classifying eosinophils as progenitors, steady state eosinophils, and Type 1 and 2 activated phenotypes. An appreciation of eosinophil regulation by non-immune tissue factors is necessary for completing the picture of eosinophil immune activation and understanding the functional contribution of these cells to development, homeostasis, and disease.

Monoclonal antibody therapy in sinonasal disease

Chronic rhinosinusitis (CRS) affects 12.5% of the U.S.

POPULATION

CRS can be divided into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps. Some individuals with CRSwNP do not respond to standard-of-care medical and surgical management. For these individuals, targeted biologic agents are emerging as an important therapeutic alternative. In this review, we described the most-relevant studies that addressed the use of anti-immunoglobulin E (omalizumab), anti-interleukin 5 (mepolizumab and reslizumab), and anti-interleukin 4/interleukin 13 (dupilumab) monoclonal antibodies for the treatment of CRSwNP. In addition, we discussed the importance of some of these clinical trials in identifying new CRS endotypes based on distinct inflammatory profiles.

Immune deficiency in chronic rhinosinusitis: screening and treatment

INTRODUCTION

Chronic rhinosinusitis (CRS) is a prevalent disease with a high annual cost of treatment. Immune deficiencies are more common in individuals with CRS and should be especially considered in those patients who are refractory to medical and surgical therapy. Areas covered: We performed a literature search in PubMed of the terms "immunodeficiency" and "sinusitis" or "rhinosinusitis" from 2006 through March 2016. All abstracts were reviewed to determine if they pertained to human disease; relevant articles were evaluated in their entirety and included in this review. Expert commentary: CRS is a common disease; in those patients with frequent exacerbations or who are refractory to treatment, an immunodeficiency evaluation should be considered. Treatment includes vaccination, antibiotic therapy, immunoglobulin replacement and surgery.

β₂-Adrenergic agonists augment air pollution-induced IL-6 release and thrombosis

Acute exposure to particulate matter (PM) air pollution causes thrombotic cardiovascular events, leading to increased mortality rates; however, the link between PM and cardiovascular dysfunction is not completely understood. We have previously shown that the release of IL-6 from alveolar macrophages is required for a prothrombotic state and acceleration of thrombosis following exposure to PM. Here, we determined that PM exposure results in the systemic release of catecholamines, which engage the β2-adrenergic receptor (β2AR) on murine alveolar macrophages and augment the release of IL-6. In mice, β2AR signaling promoted the development of a prothrombotic state that was sufficient to accelerate arterial thrombosis. In primary human alveolar macrophages, administration of a β2AR agonist augmented IL-6 release, while the addition of a beta blocker inhibited PM-induced IL-6 release. Genetic loss or pharmacologic inhibition of the β2AR on murine alveolar macrophages attenuated PM-induced IL-6 release and prothrombotic state. Furthermore, exogenous β2AR agonist therapy further augmented these responses in alveolar macrophages through generation of mitochondrial ROS and subsequent increase of adenylyl cyclase activity. Together, these results link the activation of the sympathetic nervous system by β2AR signaling with metabolism, lung inflammation, and an enhanced susceptibility to thrombotic cardiovascular events.

The effect of rosuvastatin in a murine model of influenza A infection

RATIONALE

HMG-CoA reductase inhibitors such as rosuvastatin may have immunomodulatory and anti-inflammatory effects that may reduce the severity of influenza A infection. We hypothesized that rosuvastatin would decrease viral replication, attenuate lung injury, and improve mortality following influenza A infection in mice.

METHODS

C57Bl/6 mice were treated daily with rosuvastatin (10 mg/kg/day) supplemented in chow (or control chow) beginning three days prior to infection with either A//Udorn/72 [H3N2] or A/WSN/33 [H1N1] influenza A virus (1×10(5) pfu/mouse). Plaque assays were used to examine the effect of rosuvastatin on viral replication in vitro and in the lungs of infected mice. We measured cell count with differential, protein and cytokines in the bronchoalveolar lavage (BAL) fluid, histologic evidence of lung injury, and wet-to-dry ratio on Day 1, 2, 4, and 6. We also recorded daily weights and mortality.

RESULTS

The administration of rosuvastatin had no effect on viral clearance of influenza A after infection. Weight loss, lung inflammation and lung injury severity were similar in the rosuvastatin and control treated mice. In the mice infected with influenza A (A/WSN/33), mortality was unaffected by treatment with rosuvastatin.

CONCLUSIONS

Statins did not alter the replication of influenza A in vitro or enhance its clearance from the lung in vivo. Statins neither attenuated the severity of influenza A-induced lung injury nor had an effect on influenza A-related mortality. Our data suggest that the association between HMG CoA reductase inhibitors and improved outcomes in patients with sepsis and pneumonia are not attributable to their effects on influenza A infection.