Inhaled endotoxin induces a systemic neutrophil response without affecting cardiovascular measures in a randomized cross-over exposure study.

OBJECTIVE: The gram-negative bacterial cell wall component endotoxin (lipopolysaccharide, LPS) is a key component of particulate matter (PM). PM exposure is associated with cardiovascular morbidity and mortality. However, the contribution of individual components of PM to acute and chronic cardiovascular measures is not clear. This study examines whether systemic inflammation induced by LPS inhalation causes acute changes in cardiovascular physiology measures. MATERIALS AND METHODS: In this double blinded, placebo-controlled crossover study, fifteen adult volunteers underwent inhalation exposure to 20,000 EU Clinical Center Reference Endotoxin (CCRE). Peripheral blood and induced sputum neutrophils were obtained at baseline and six hours post-exposure. Blood pressure, measures of left ventricular function (ejection fraction (LVEF) and global longitudinal strain (LVGLS)), and indices of endothelial function (flow mediated dilation (FMD) and velocity time integral during hyperemia (VTIhyp)) were measured before and after treatment. Wilcoxon sign-rank tests and linear mixed models were used for statistical analysis. RESULTS: In comparison with normal saline, LPS inhalation resulted in significant increases in peripheral blood and sputum neutrophils but was not associated with significant alterations in blood pressure, LVGLS, LVEF, FMD, or VTIhyp. DISCUSSION AND CONCLUSIONS: In healthy adults, systemic inflammation after LPS inhalation was not associated with acute changes in cardiovascular physiology. Larger studies are needed to investigate the effects of other PM components on inflammation induced cardiovascular dysfunction.

Treating asthma in the time of COVID.

The Precision Interventions for Severe and/or Exacerbation-Prone Asthma clinical trials network is actively assessing novel treatments for severe asthma during the coronavirus disease (COVID-19) pandemic and has needed to adapt to various clinical dilemmas posed by the COVID-19 pandemic. Pharmacologic interactions between established asthma therapies and novel drug interventions for COVID-19 infection, including antivirals, biologics, and vaccines, have emerged as a critical and unanticipated issue in the clinical care of asthma. In particular, impaired metabolism of some long-acting beta-2 agonists by the cytochrome P4503A4 enzyme in the setting of antiviral treatment using ritonavir-boosted nirmatrelvir (NVM/r, brand name Paxlovid) may increase risk for adverse cardiovascular events. Although available data have documented the potential for such interactions, these issues are largely unappreciated by clinicians who treat asthma, or those dispensing COVID-19 interventions in patients who happen to have asthma. Because these drug-drug interactions have not previously been relevant to patient care, clinicians have had no guidance on management strategies to reduce potentially serious interactions between treatments for asthma and COVID-19. The Precision Interventions for Severe and/or Exacerbation-Prone Asthma network considered the available literature and product information, and herein share our considerations and plans for treating asthma within the context of these novel COVID-19-related therapies.

Effects of combination treatment with tezepelumab and allergen immunotherapy on nasal responses to allergen: A randomized controlled trial.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) has been shown to play a central role in the initiation and persistence of allergic responses. OBJECTIVE: We evaluated whether tezepelumab, a human monoclonal anti-TSLP antibody, improved the efficacy of subcutaneous allergen immunotherapy (SCIT) and promoted the development of tolerance in patients with allergic rhinitis. METHODS: We conducted a double-blind parallel design trial in patients with cat allergy. A total of 121 patients were randomized to receive either intravenous tezepelumab plus subcutaneous cat SCIT, cat SCIT alone, tezepelumab alone, or placebo for 52 weeks, followed by 52 weeks of observation. Nasal allergen challenge (NAC), skin testing, and blood and nasal samples were obtained throughout the study. RESULTS: At week 52, the NAC-induced total nasal symptom scores (TNSS) (calculated as area under the curve [AUC0-1h] and as peak score [Peak0-1h] during the first hour after NAC) were significantly reduced in patients receiving tezepelumab/SCIT compared to SCIT alone. At week 104, one year after stopping treatment, the primary end point TNSS AUC0-1h was not significantly different in the tezepelumab/SCIT group compared to SCIT alone, while TNSS Peak0-1h was significantly lower in those receiving combination treatment versus SCIT. Transcriptomic analysis of nasal epithelial samples demonstrated that treatment with the combination of SCIT/tezepelumab, but neither monotherapy, caused persistent downregulation of a gene network related to type 2 inflammation that was associated with improvement in NAC responses. CONCLUSIONS: Inhibition of TSLP augments the efficacy of SCIT during therapy and may promote tolerance after a 1-year course of treatment. (ClinicalTrials.gov NCT02237196).

The Precision Interventions for Severe and/or Exacerbation-Prone (PrecISE) Asthma Network: An overview of Network organization, procedures, and interventions.

Asthma is a heterogeneous disease, with multiple underlying inflammatory pathways and structural airway abnormalities that impact disease persistence and severity. Recent progress has been made in developing targeted asthma therapeutics, especially for subjects with eosinophilic asthma. However, there is an unmet need for new approaches to treat patients with severe and exacerbation-prone asthma, who contribute disproportionately to disease burden. Extensive deep phenotyping has revealed the heterogeneous nature of severe asthma and identified distinct disease subtypes. A current challenge in the field is to translate new and emerging knowledge about different pathobiologic mechanisms in asthma into patient-specific therapies, with the ultimate goal of modifying the natural history of disease. Here, we describe the Precision Interventions for Severe and/or Exacerbation-Prone Asthma (PrecISE) Network, a groundbreaking collaborative effort of asthma researchers and biostatisticians from around the United States. The PrecISE Network was designed to conduct phase II/proof-of-concept clinical trials of precision interventions in the population with severe asthma, and is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health. Using an innovative adaptive platform trial design, the PrecISE Network will evaluate up to 6 interventions simultaneously in biomarker-defined subgroups of subjects. We review the development and organizational structure of the PrecISE Network, and choice of interventions being studied. We hope that the PrecISE Network will enhance our understanding of asthma subtypes and accelerate the development of therapeutics for severe asthma.

EAACI position paper on the clinical use of the bronchial allergen challenge: Unmet needs and research priorities.

Allergic asthma (AA) is a common asthma phenotype, and its diagnosis requires both the demonstration of IgE-sensitization to aeroallergens and the causative role of this sensitization as a major driver of asthma symptoms. Therefore, a bronchial allergen challenge (BAC) would be occasionally required to identify AA patients among atopic asthmatics. Nevertheless, BAC is usually considered a research tool only, with existing protocols being tailored to mild asthmatics and research needs (eg long washout period for inhaled corticosteroids). Consequently, existing BAC protocols are not designed to be performed in moderate-to-severe asthmatics or in clinical practice. The correct diagnosis of AA might help select patients for immunomodulatory therapies. Allergen sublingual immunotherapy is now registered and recommended for controlled or partially controlled patients with house dust mite-driven AA and with FEV1 ≥ 70%. Allergen avoidance is costly and difficult to implement for the management of AA, so the proper selection of patients is also beneficial. In this position paper, the EAACI Task Force proposes a methodology for clinical BAC that would need to be validated in future studies. The clinical implementation of BAC could ultimately translate into a better phenotyping of asthmatics in real life, and into a more accurate selection of patients for long-term and costly management pathways.

Development of a screening protocol to identify persons who are responsive to wood smoke particle-induced airway inflammation with pilot assessment of GSTM1 genotype and asthma status as response modifiers.

BACKGROUND: We are currently screening human volunteers to determine their sputum polymorphonuclear neutrophil (PMN) response 6- and 24-hours following initiation of exposure to wood smoke particles (WSP). Inflammatory responders (≥10% increase in %PMN) are identified for their subsequent participation in mitigation studies against WSP-induced airways inflammation. In this report we compared responder status (<i>N</i> = 52) at both 6 and 24 hr time points to refine/expand its classification, assessed the impact of the GSTM1 genotype, asthma status and sex on responder status, and explored whether sputum soluble phase markers of inflammation correlate with PMN responsiveness to WSP. RESULTS: Six-hour responders tended to be 24-hour responders and vice versa, but 24-hour responders also had significantly increased IL-1beta, IL-6, IL-8 at 24 hours post WSP exposure. The GSTM1 null genotype significantly (<i>p</i> &lt; 0.05) enhanced the %PMN response by 24% in the 24-hour responders and not at all in the 6 hours responders. Asthma status enhanced the 24 hour %PMN response in the 6- and 24-hour responders. In the entire cohort (not stratified by responder status), we found a significant, but very small decrease in FVC and systolic blood pressure immediately following WSP exposure and sputum %PMNs were significantly increased and associated with sputum inflammatory markers (IL-1beta, IL-6, IL-8, and PMN/mg) at 24 but not 6 hours post exposure. Blood endpoints in the entire cohort showed a significant increase in %PMN and PMN/mg at 6 but not 24 hours. Sex had no effect on %PMN response. CONCLUSIONS: The 24-hour time point was more informative than the 6-hour time point in optimally and expansively defining airway inflammatory responsiveness to WSP exposure. GSTM1 and asthma status are significant effect modifiers of this response. These study design and subject parameters should be considered before enrolling volunteers for proof-of-concept WSP mitigation studies.

PrecISE: Precision Medicine in Severe Asthma: An adaptive platform trial with biomarker ascertainment.

Severe asthma accounts for almost half the cost associated with asthma. Severe asthma is driven by heterogeneous molecular mechanisms. Conventional clinical trial design often lacks the power and efficiency to target subgroups with specific pathobiological mechanisms. Furthermore, the validation and approval of new asthma therapies is a lengthy process. A large proportion of that time is taken by clinical trials to validate asthma interventions. The National Institutes of Health Precision Medicine in Severe and/or Exacerbation Prone Asthma (PrecISE) program was established with the goal of designing and executing a trial that uses adaptive design techniques to rapidly evaluate novel interventions in biomarker-defined subgroups of severe asthma, while seeking to refine these biomarker subgroups, and to identify early markers of response to therapy. The novel trial design is an adaptive platform trial conducted under a single master protocol that incorporates precision medicine components. Furthermore, it includes innovative applications of futility analysis, cross-over design with use of shared placebo groups, and early futility analysis to permit more rapid identification of effective interventions. The development and rationale behind the study design are described. The interventions chosen for the initial investigation and the criteria used to identify these interventions are enumerated. The biomarker-based adaptive design and analytic scheme are detailed as well as special considerations involved in the final trial design.

Systemic inflammatory response to inhaled endotoxin does not correlate with airway response.

BACKGROUND: Endotoxin is a component of particulate matter linked to respiratory disease. Our group has shown that experimental endotoxin inhalation challenge reproducibly triggers neutrophilic inflammation in the airways and in peripheral blood. Sputum induction is currently the only available method for assessing airway neutrophilia but is laborious and time-consuming. This analysis examined the correlation between systemic and airway inflammatory responses to endotoxin to determine if peripheral blood could serve as a surrogate marker for neutrophilic airway inflammation. METHODS: We conducted a retrospective study of 124 inhaled endotoxin challenges conducted at our center using 20,000 endotoxin units (EU) of Clinical Center Reference Endotoxin (CCRE). Venipuncture and induced sputum samples were obtained at baseline and 6 hours after completion of endotoxin challenge. The relationship between change in sputum neutrophils (post-challenge - baseline) and change in peripheral blood neutrophils (post-challenge - baseline) was assessed using Spearman's correlation analyses. RESULTS: Inhaled endotoxin induced a significant increase in mean sputum percent neutrophils and peripheral blood absolute neutrophil counts in healthy adults with or without mild asthma, but no significant correlation was found between airway and systemic neutrophilia (r = 0.13, p = 0.18). Stratification by degree of airway neutrophil response and by atopic or asthmatic status did not change the results. CONCLUSIONS: Inhalation challenge with endotoxin safely and effectively induces airway neutrophilic inflammation in most individuals. Increases in endotoxin-induced peripheral blood neutrophils do not correlate well with airway responses and should not be used as a surrogate marker of airway inflammation.

Emerging concepts and challenges in implementing the exposome paradigm in allergic diseases and asthma: a Practall document.

Exposome research can improve the understanding of the mechanistic connections between exposures and health to help mitigate adverse health outcomes across the life span. The exposomic approach provides a risk profile instead of single predictors and thus is particularly applicable to allergic diseases and asthma. Under the PRACTALL collaboration between the European Academy of Allergy and Clinical Immunology (EAACI) and the American Academy of Allergy, Asthma, and Immunology (AAAAI), we evaluated the current concepts and the unmet needs on the role of the exposome in allergic diseases and asthma.

The "envirome" and what the practitioner needs to know about it.

OBJECTIVE: This review on the "envirome" focuses on pollution, microbial, and social stressor elements of the environment that may impact development or expression of allergic diseases. DATA SOURCES: Peer-reviewed publications on the impact of environmental factors indexed in PubMed were the primary data source for this review. STUDY SELECTIONS: The primary search strategy for this review employed cross-referencing asthma, atopic dermatitis, and immunoglobulin E (IgE) against pollution (ozone, particulate matter, nitrogen oxides, tobacco smoke), microbial exposures (farm exposure, microbiome, infection, antibiotic use) and psychosocial stressors, with emphasis on results in the past 5 years, with inclusion of key seminal articles or comprehensive reviews. RESULTS: Air pollution is a clear cause of allergic disease exacerbation, with increasing recognition that pollutant exposure increases risk of allergic disease. Microbial exposures and maternal and child stress also modulate development and expression of allergic disease. Early life exposures are especially critical periods during which all of these factors have notable impacts on allergic disease. CONCLUSION: Nonallergenic environmental factors are important modulators and adjuvants for development of allergic disease, with early life exposures being especially important. Development and validation of interventions directed toward these factors during early life is a significant opportunity for primary prevention of allergic disease.

Sex, obesity, diabetes, and exposure to particulate matter among patients with severe asthma: Scientific insights from a comparative analysis of open clinical data sources during a five-day hackathon.

This special communication describes activities, products, and lessons learned from a recent hackathon that was funded by the National Center for Advancing Translational Sciences via the Biomedical Data Translator program ('Translator'). Specifically, Translator team members self-organized and worked together to conceptualize and execute, over a five-day period, a multi-institutional clinical research study that aimed to examine, using open clinical data sources, relationships between sex, obesity, diabetes, and exposure to airborne fine particulate matter among patients with severe asthma. The goal was to develop a proof of concept that this new model of collaboration and data sharing could effectively produce meaningful scientific results and generate new scientific hypotheses. Three Translator Clinical Knowledge Sources, each of which provides open access (via Application Programming Interfaces) to data derived from the electronic health record systems of major academic institutions, served as the source of study data. Jupyter Python notebooks, shared in GitHub repositories, were used to call the knowledge sources and analyze and integrate the results. The results replicated established or suspected relationships between sex, obesity, diabetes, exposure to airborne fine particulate matter, and severe asthma. In addition, the results demonstrated specific differences across the three Translator Clinical Knowledge Sources, suggesting cohort- and/or environment-specific factors related to the services themselves or the catchment area from which each service derives patient data. Collectively, this special communication demonstrates the power and utility of intense, team-oriented hackathons and offers general technical, organizational, and scientific lessons learned.

A community-engaged approach to investigate cardiovascular-associated inflammation among American Indian women: A research protocol.

American Indian women are more likely to die from cardiovascular disease (CVD) than White or African American women. Inflammatory processes may underlie CVD disparities by gender and race and may be critical to understanding population-specific drivers and potential buffers. Exposure to environmental air pollutants, especially particulate matter (PM), is known to be an important catalyst in CVD-associated inflammation. Positive psychological states, associated with low levels of inflammatory gene expression, could serve to moderate the inflammatory response to environmental air pollutants and ultimately lead to better cardiovascular health outcomes. The aim of the ongoing community-engaged and NIH-funded study described in this study protocol is to address the racial and gender gaps in CVD mortality by investigating the contextually relevant and culturally important determinants of health among American Indian women. In this paper we describe the procedures used to examine the relationship between environmental air pollutant exposures (PM10-2.5 and PM 2.5 ), psychological factors (e.g., depressive symptoms, posttraumatic stress symptoms, eudemonic well-being, and positive emotions), and cardiovascular-associated inflammation (hs-CRP, IL-6, Amyloid A, CBCs with differentials) in a sample of 150 women 18-50 years of age from the Lumbee Tribe in southeastern North Carolina. We describe lessons learned and strategies used in developing a community-engaged approach to enhance recruitment of American Indian women in biomedical research. The empirical data and community infrastructure resulting from this study will be foundational in designing and testing future interventions to reduce CVD-associated morbidity and mortality in American Indian women.

Gamma tocopherol-enriched supplement reduces sputum eosinophilia and endotoxin-induced sputum neutrophilia in volunteers with asthma.

BACKGROUND: We and others have shown that the gamma tocopherol (γT) isoform of vitamin E has multiple anti-inflammatory and antioxidant actions and that γT supplementation reduces eosinophilic and endotoxin (LPS)-induced neutrophilic airway inflammation in animal models and healthy human volunteers. OBJECTIVE: We sought to determine whether γT supplementation reduces eosinophilic airway inflammation and acute neutrophilic response to inhaled LPS challenge in volunteers with asthma. METHODS: Participants with mild asthma were enrolled in a double-blinded, placebo-controlled crossover study to assess the effect of 1200 mg of γT daily for 14 days on sputum eosinophils, mucins, and cytokines. We also assessed the effect on acute inflammatory response to inhaled LPS challenge following γT treatment, focusing on changes in sputum neutrophilia, mucins, and cytokines. Mucociliary clearance was measured using gamma scintigraphy. RESULTS: Fifteen subjects with mild asthma completed both arms of the study. Compared with placebo, γT notably reduced pre-LPS challenge sputum eosinophils and mucins, including mucin 5AC and reduced LPS-induced airway neutrophil recruitment 6 and 24 hours after challenge. Mucociliary clearance was slowed 4 hours postchallenge in the placebo group but not in the γT treatment group. Total sputum mucins (but not mucin 5AC) were reduced at 24 hours postchallenge during γT treatment compared with placebo. CONCLUSIONS: When compared with placebo, γT supplementation for 14 days reduced inflammatory features of asthma, including sputum eosinophils and mucins, as well as acute airway response to inhaled LPS challenge. Larger scale clinical trials are needed to assess the efficacy of γT supplements as a complementary or steroid-sparing treatment for asthma.

Neuropilin-2 regulates airway inflammatory responses to inhaled lipopolysaccharide.

Neuropilins are multifunctional receptors that play important roles in immune regulation. Neuropilin-2 (NRP2) is expressed in the lungs, but whether it regulates airway immune responses is unknown. Here, we report that Nrp2 is weakly expressed by alveolar macrophages (AMs) in the steady state but is dramatically upregulated following in vivo lipopolysaccharide (LPS) inhalation. Ex vivo treatment of human AMs with LPS also increased NRP2 mRNA expression and cell-surface display of NRP2 protein. LPS-induced Nrp2 expression in AMs was dependent upon the myeloid differentiation primary response 88 signaling pathway and the transcription factor NF-κB. In addition to upregulating display of NRP2 on the cell membrane, inhaled LPS also triggered AMs to release soluble NRP2 into the airways. Finally, myeloid-specific ablation of NRP2 resulted in increased expression of the chemokine (C-C motif) ligand 2 ( Ccl2) in the lungs and prolonged leukocyte infiltration in the airways following LPS inhalation. These findings suggest that NRP2 expression by AMs regulates LPS-induced inflammatory cell recruitment to the airways and reveal a novel role for NRP2 during innate immune responses in the lungs.

Mucus Hydration in Subjects with Stable Chronic Bronchitis: A Comparison of Spontaneous and Induced Sputum.

Mucus hydration is important in mucus clearance and lung health. This study sought to test the relative utility of spontaneous sputum (SS) versus the reasonably noninvasive induced sputum (IS) samples for measurement of mucus hydration. SS and IS samples were collected over a 2-day study interval. Sputum was induced with escalating inhaled nebulized 3-5% hypertonic saline. Viscous portions of the samples ("plugs") were utilized for percent solids and total mucin analyses. Cytokines, nucleotides/nucleosides and cell differentials were measured in plugs diluted into 0.1% Sputolysin. Overall, 61.5% of chronic bronchitis (CB) subjects produced a SS sample and 95.2% an IS sample. Total expectorate sample weights were less for the SS (0.94 ± 0.98 g) than the IS (2.67 ± 2.33 g) samples. Percent solids for the SS samples (3.56% ± 1.95; n = 162) were significantly greater than the IS samples (3.08% ± 1.81; n = 121), p = 0.133. Total mucin concentrations also exhibited a dilution of the IS samples: SS = 4.15 ± 3.23 mg/ml (n = 62) versus IS= 3.34 ± 2.55 mg/ml (n = 71) (p = 0.371). Total mucins (combined SS and IS) but not percent solids, were inversely associated with FEV1 percent predicted (p = 0.052) and FEV1,/FVC % (p = 0.035). There were no significant differences between sample types in cytokine or differential cell counts. The probability of sample collections was less for SS than IS samples. Measurements of hydration revealed modest dilution of the IS samples compared to SS. Thus for measurements of mucus hydration, both SS and IS samples appear to be largely interchangeable.

Advances in environmental and occupational disorders in 2016.

In this review we highlight recent studies that advance the knowledge and understanding of the effects of various environmental factors and associated immune responses in patients with allergic diseases. This review will focus on new literature regarding allergic and immune responses to a variety of environmental factors, including aeroallergens, stinging insects, fungi, pollutants, viral respiratory tract infections, climate change, and microbial exposures.

Environmental determinants of allergy and asthma in early life.

Allergic disease prevalence has increased significantly in recent decades. Primary prevention efforts are being guided by study of the exposome (or collective environmental exposures beginning during the prenatal period) to identify modifiable factors that affect allergic disease risk. In this review we explore the evidence supporting a relationship between key components of the external exposome in the prenatal and early-life periods and their effect on atopy development focused on microbial, allergen, and air pollution exposures. The abundance and diversity of microbial exposures during the first months and years of life have been linked with risk of allergic sensitization and disease. Indoor environmental allergen exposure during early life can also affect disease development, depending on the allergen type, dose, and timing of exposure. Recent evidence supports the role of ambient air pollution in allergic disease inception. The lack of clarity in the literature surrounding the relationship between environment and atopy reflects the complex interplay between cumulative environmental factors and genetic susceptibility, such that no one factor dictates disease development in all subjects. Understanding the effect of the summation of environmental exposures throughout a child's development is needed to identify cost-effective interventions that reduce atopy risk in children.

Health and the Environment in North Carolina.

Environmental impacts on health are usually discussed from a global perspective. However, this issue of the North Carolina Medical Journal focuses on studies of health outcomes in North Carolina caused by local air and water pollution. While some people are clearly at increased risk, environmental threats to health ultimately impact all of us.

Safety and benefits of inhaled hypertonic saline following airway challenges with endotoxin and allergen in asthmatics.

OBJECTIVE: To determine whether induced sputum (IS) with hypertonic saline inhalation is safe to use in asthmatics within 24 hours of two commonly used airway challenges, namely endotoxin and dust mite allergen, and to assess whether IS can enhance mucociliary clearance (MCC) rates in asthmatics. METHODS: IS (three 7-minute inhalation periods of 3%, 4%, and 5% hypertonic saline) was employed before (N = 29) and within 24 hours of inhaled challenges with endotoxin (N = 13) and dust mite allergen (N = 12) in a cohort of mild to moderate asthmatics. Safety was assessed by lung function (Forced Expiratory Volume in 1 second; FEV1) and MCC was measured using a radiolabeled gamma scintigraphy method (Tcm99 sulfur colloid). IS was performed pre and post MCC. RESULTS: No significant lung function decrement was observed before or after inhaled challenges with endotoxin or dust mite allergen. IS significantly enhanced MCC rates before and after inhaled endotoxin challenge. CONCLUSION: Based on a small cohort, IS is safe to use in mild to moderate asthmatics before and within 24 hours of inhaled challenges with endotoxin and dust mite allergen. Furthermore, IS has beneficial effects on host defense function in asthmatics by enhancing MCC rates.