Eosinophilic inflammation in allergic asthma

Vinpocetine, a phosphodiesterase 1 inhibitor, mitigates atopic dermatitis-like skin inflammation

Atopic dermatitis (AD) is the most common inflammatory pruritic skin disease worldwide, characterized by the infiltration of multiple pathogenic T lymphocytes and histological symptoms such as epidermal and dermal thickening. This study aims to investigate the effect of vinpocetine (Vinp; a phosphodiesterase 1 inhibitor) on a 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD-like model. DNCB (1%) was administered on day 1 in the AD model. Subsequently, from day 14 onward, mice in each group (Vinp-treated groups: 1 mg/kg and 2 mg/kg and dexamethasone- treated group: 2 mg/kg) were administered 100 µl of a specific drug daily, whereas 0.2% DNCB was administered every other day for 30 min over 14 days. The Vinp-treated groups showed improved Eczema Area and Severity Index scores and trans-epidermal water loss, indicating the efficacy of Vinp in improving AD and enhancing skin barrier function. Histological analysis further confirmed the reduction in hyperplasia of the epidermis and the infiltration of inflammatory cells, including macrophages, eosinophils, and mast cells, with Vinp treatment. Moreover, Vinp reduced serum concentrations of IgE, interleukin (IL)-6, IL-13, and monocyte chemotactic protein-1. The mRNA levels of IL-1β, IL-6, Thymic stromal lymphopoietin, and transforming growth factor-beta (TGF-β) were reduced by Vinp treatment. Reduction of TGF-β protein by Vinp in skin tissue was also observed. Collectively, our results underscore the effectiveness of Vinp in mitigating DNCB-induced AD by modulating the expression of various biomarkers. Consequently, Vinp is a promising therapeutic candidate for treating AD.

EndoPRS: Incorporating Endophenotype Information to Improve Polygenic Risk Scores for Clinical Endpoints

Polygenic risk score (PRS) prediction of complex diseases can be improved by leveraging related phenotypes. This has motivated the development of several multi-trait PRS methods that jointly model information from genetically correlated traits. However, these methods do not account for vertical pleiotropy between traits, in which one trait acts as a mediator for another. Here, we introduce endoPRS, a weighted lasso model that incorporates information from relevant endophenotypes to improve disease risk prediction without making assumptions about the genetic architecture underlying the endophenotype-disease relationship. Through extensive simulation analysis, we demonstrate the robustness of endoPRS in a variety of complex genetic frameworks. We also apply endoPRS to predict the risk of childhood onset asthma in UK Biobank by leveraging a paired GWAS of eosinophil count, a relevant endophenotype. We find that endoPRS significantly improves prediction compared to many existing PRS methods, including multi-trait PRS methods, MTAG and wMT-BLUP, which suggests advantages of endoPRS in real-life clinical settings.

Eosinophils and Cognitive Impairment in Schizophrenia: A New Perspective

Schizophrenia is a complex psychiatric disorder characterized by a wide array of cognitive impairments. While research has predominantly focused on the neurological aspects of schizophrenia, emerging evidence suggests that the immune system, specifically eosinophils, may play a significant role in the cognitive deficits associated with the disorder. This review presents a novel perspective on the interplay between eosinophils and cognitive impairment in schizophrenia. Eosinophils, traditionally associated with allergic responses and inflammation, have garnered limited attention within the realm of neuropsychiatry. Recent studies have hinted at a potential link between eosinophil activation and the pathogenesis of schizophrenia. In this comprehensive review, we delve into the world of eosinophils, elucidating their nature, functions, and interactions with the immune system. We examine the cognitive deficits observed in individuals with schizophrenia and discuss existing theories on the etiology of these impairments, focusing on immune system involvement. The paper also highlights the evolving body of research that supports the idea of eosinophilic influence on schizophrenia-related cognitive deficits. Furthermore, we explore potential mechanisms through which eosinophils may exert their effects on cognitive function in schizophrenia, including interactions with other immune cells and inflammatory pathways. By discussing the clinical implications and potential therapeutic avenues stemming from this newfound perspective, we underscore the practical significance of this emerging field of research. While this paper acknowledges the limitations and challenges inherent in studying eosinophils within the context of schizophrenia, it serves as a posit for novel thought in this vexing disease space as well as a call to action for future research endeavors. By providing a comprehensive survey of the existing literature and posing unanswered questions, we aim to inspire a reimagining of the relationship between eosinophils and cognitive impairment in schizophrenia, ultimately advancing our understanding and treatment of this debilitating disorder.

Heat-killed Akkermansia muciniphila ameliorates allergic airway inflammation in mice

Allergic asthma (AA) is a common inflammatory airway disease characterized by increased airway hyper-responsiveness (AHR), inflammation, and remodeling. Akkermansia muciniphila is a strictly anaerobic bacterium residing in the gut and is a promising next-generation probiotic to improve metabolic inflammatory syndrome. A recent study suggested the beneficial effect of live A. muciniphila on allergic airway inflammation (AAI) in mice. However, whether the heat-killed form can improve AAI requires further investigation. Mice sensitized and challenged with house dust mites (HDM) develop AA hallmarks including inflammatory cell infiltration, goblet cell hyperplasia, and subepithelial collagen deposition in the lungs. These phenomena were reversed by oral administration of the heat-killed A. muciniphila strain EB-AMDK19 (AMDK19-HK) isolated from the feces of healthy Koreans. Furthermore, AMDK19-HK diminished the HDM-induced AHR to inhaled methacholine, lung mast cell accumulation, and serum HDM-specific IgE levels. It also led to the overall suppression of IL-4, IL-13, and eotaxin production in bronchoalveolar lavage fluids, and Il4, Il5, Il13, and Ccl17 gene expression in lung tissues. Moreover, AMDK19-HK suppressed Th2-associated cytokine production in the splenocytes of HDM-sensitized mice in vitro. Additionally, a combination of 16S rRNA gene sequencing and short-chain fatty acid (SCFA) analysis in cecal samples revealed that AMDK19-HK modulated the relative abundance of circulating SCFA-associated gut genera, including a positive correlation with Lachnospiraceae_ NK4A136_group and a negative correlation with Lachnoclostridium and significantly increased cecal SCFA concentrations. Finally, AMDK19-HK improved intestinal mucosal barrier function. These results suggest that the oral administration of AMDK19-HK ameliorates HDM-induced AAI in mice by suppressing Th2-mediated immune responses and could have a protective effect against AA development.

Immunoregulatory role of hesperidin against ovalbumin (OVA)-induced bronchial asthma and depression in rats

Links between bronchial asthma and depression have recently become a great subject of interest. The present study was carried out to assess the protective role of hesperidin against ovalbumin (OVA)-induced bronchial asthma that is associated with depression in rats, for this purpose, four groups. Rats were sensitized with intraperitoneal administration of 200 μg OVA/10 mg aluminum hydroxide (Al (OH) 3 for 3 consecutive days then at day 11 followed by intranasal challenge with OVA (1.5 mg/kg) at days 19, 20, and 21. Rats were pretreated with hesperidin (100 & 200 mg/kg) 1h before OVA challenge. At the end of the study, behavioral tests, biochemical indices, and histopathological architectures of lung and brain tissues were evaluated. Our findings showed that hesperidin significantly ameliorated the reduction in motor activity, motor coordination, forced swimming, CD4, CD25 and foxp3, interleukin-10 (IL-10), dopamine, serotonin, and neurotrophin-3 (NT3) as well as alleviated the elevation in transforming growth factor-beta (TGF-β), tumor necrosis factor-alpha (TNF-α), iL-5, and immunoglobulin E (IgE). In addition, hesperidin reduced cellular infiltration, alveolar sacs damage, the bronchioles wall disruption, and nuclei pyknosis in neuron cells. Finally, hesperidin may provide protection against OVA-induced asthma and depression. This impact could be mediated in part by its anti-inflammatory and immunoregulatory properties.

Airway remodelling in asthma and the epithelium: on the edge of a new era

Asthma is a chronic, heterogeneous disease of the airways, often characterised by structural changes known collectively as airway remodelling. In response to environmental insults, including pathogens, allergens and pollutants, the epithelium can initiate remodelling via an inflammatory cascade involving a variety of mediators that have downstream effects on both structural and immune cells. These mediators include the epithelial cytokines thymic stromal lymphopoietin, interleukin (IL)-33 and IL-25, which facilitate airway remodelling through cross-talk between epithelial cells and fibroblasts, and between mast cells and airway smooth muscle cells, as well as through signalling with immune cells such as macrophages. The epithelium can also initiate airway remodelling independently of inflammation in response to the mechanical stress present during bronchoconstriction. Furthermore, genetic and epigenetic alterations to epithelial components are believed to influence remodelling. Here, we review recent advances in our understanding of the roles of the epithelium and epithelial cytokines in driving airway remodelling, facilitated by developments in genetic sequencing and imaging techniques. We also explore how new and existing therapeutics that target the epithelium and epithelial cytokines could modify airway remodelling.

Different bacterial cargo in apoptotic cells drive distinct macrophage phenotypes

The removal of dead cells (efferocytosis) contributes to the resolution of the infection and preservation of the tissue. Depending on the environment milieu, macrophages may show inflammatory (M1) or anti-inflammatory (M2) phenotypes. Inflammatory leukocytes are recruited during infection, followed by the accumulation of infected and non-infected apoptotic cells (AC). Efferocytosis of non-infected AC promotes TGF-β, IL-10, and PGE2 production and the polarization of anti-inflammatory macrophages. These M2 macrophages acquire an efficient ability to remove apoptotic cells that are involved in tissue repair and resolution of inflammation. On the other hand, the impact of efferocytosis of infected apoptotic cells on macrophage activation profile remains unknown. Here, we are showing that the efferocytosis of gram-positive Streptococcus pneumoniae-AC (Sp-AC) or gram-negative Klebsiella pneumoniae-AC (Kp-AC) promotes distinct gene expression and cytokine signature in macrophages. Whereas the efferocytosis of Kp-AC triggered a predominant M1 phenotype in vitro and in vivo, the efferocytosis of Sp-AC promoted a mixed M1/M2 activation in vitro and in vivo in a model of allergic asthma. Together, these findings suggest that the nature of the pathogen and antigen load into AC may have different impacts on inducing macrophage polarization.

The airway epithelium: an orchestrator of inflammation, a key structural barrier and a therapeutic target in severe asthma

Asthma is a disease of heterogeneous pathology, typically characterised by excessive inflammatory and bronchoconstrictor responses to the environment. The clinical expression of the disease is a consequence of the interaction between environmental factors and host factors over time, including genetic susceptibility, immune dysregulation and airway remodelling. As a critical interface between the host and the environment, the airway epithelium plays an important role in maintaining homeostasis in the face of environmental challenges. Disruption of epithelial integrity is a key factor contributing to multiple processes underlying asthma pathology. In this review, we first discuss the unmet need in asthma management and provide an overview of the structure and function of the airway epithelium. We then focus on key pathophysiological changes that occur in the airway epithelium, including epithelial barrier disruption, immune hyperreactivity, remodelling, mucus hypersecretion and mucus plugging, highlighting how these processes manifest clinically and how they might be targeted by current and novel therapeutics.

Granular Insights: Neutrophil Predominance and Elastase Release in Severe Asthma Exacerbations in a Pediatric Cohort

The chronic inflammatory component of asthma is propagated by granulocytes, including neutrophils and eosinophils, in the peripheral circulation and airway. Previous studies have suggested that these cells have an altered expression of adhesion-related molecules and a propensity for the release of granule contents that may contribute to tissue damage and enhance inflammatory complications in patients with status asthmaticus. The goal of this prospective cohort study at a tertiary care pediatric hospital with a large population of asthma patients was to assess the role of granulocyte-based inflammation in the development of asthma exacerbation. Subjects were enrolled from two patient populations: those with mild-to-moderate asthma exacerbations seen in the emergency department and those with severe asthma admitted to the intensive care unit (PICU). Clinical data were collected, and blood was drawn. Granulocytes were immediately purified, and the phenotype was assessed, including the expression of cell surface markers, elastase release, and cytokine production. Severe asthmatics admitted to the PICU displayed a significantly higher total neutrophil count when compared with healthy donors. Moreover, little to no eosinophils were found in granulocyte preparations from severe asthmatics. Circulating neutrophils from severe asthmatics admitted to the PICU displayed significantly increased elastase release ex vivo when compared with the PMN from healthy donors. These data suggest that the neutrophil-based activation and release of inflammatory products displayed by severe asthmatics may contribute to the propagation of asthma exacerbations.

Armeniacae semen amarum: a review on its botany, phytochemistry, pharmacology, clinical application, toxicology and pharmacokinetics

Armeniacae semen amarum-seeds of Prunus armeniaca L. (Rosaceae) (ASA), also known as Kuxingren in Chinese, is a traditional Chinese herbal drug commonly used for lung disease and intestinal disorders. It has long been used to treat coughs and asthma, as well as to lubricate the colon and reduce constipation. ASA refers to the dried ripe seed of diverse species of Rosaceae and contains a variety of phytochemical components, including glycosides, organic acids, amino acids, flavonoids, terpenes, phytosterols, phenylpropanoids, and other components. Extensive data shows that ASA exhibits various pharmacological activities, such as anticancer activity, anti-oxidation, antimicrobial activity, anti-inflammation, protection of cardiovascular, neural, respiratory and digestive systems, antidiabetic effects, and protection of the liver and kidney, and other activities. In clinical practice, ASA can be used as a single drug or in combination with other traditional Chinese medicines, forming ASA-containing formulas, to treat various afflictions. However, it is important to consider the potential adverse reactions and pharmacokinetic properties of ASA during its clinical use. Overall, with various bioactive components, diversified pharmacological actions and potent efficacies, ASA is a promising drug that merits in-depth study on its functional mechanisms to facilitate its clinical application.

Amelioration of ovalbumin-induced lung inflammation in a mouse model by Trichinella spiralis novel cystatin

Background and Aims

Asthma, a chronic disease affecting humans and animals, has recently become increasingly prevalent and steadily widespread. The alternative treatment of asthma using helminth infections or helminth-derived immunomodulatory molecules (IMs) has been evaluated and demonstrated significant amelioration of disease severity index in vitro and in vivo. Trichinella spiralis, a parasitic nematode and its IMs, elicits a potential to relieve asthma and other immune-related disorders. In this study, we investigated the immunomodulatory function of recombinant T. spiralis novel cystatin (rTsCstN) in ameliorating acute inflammatory asthma disorders in a murine model.

Materials and Methods

Female BALB/c mice were sensitized using intraperitoneal injection of ovalbumin (OVA)/alum and subsequently challenged with intranasal administration of OVA alone or OVA + rTsCstN for 3 consecutive days, producing OVA-induced allergic asthma models. To evaluate the therapeutic efficacy of rTsCstN, the inflammatory cells and cytokines in bronchoalveolar lavage fluid (BALF) and OVA-specific immunoglobulin E levels in serum were assessed. Histological alterations in the lung tissues were determined by hematoxylin and eosin (H&E) staining and eventually scored for the extent of inflammatory cell infiltration.

Results

The asthmatic mouse models challenged with OVA + rTsCstN demonstrated a significant reduction of eosinophils (p < 0.01), macrophages (p < 0.05), and cytokines tumor necrosis factor-α (p < 0.05) and interferon (IFN)-γ (p < 0.05) in BALF when compared with the mice challenged with OVA alone. However, the levels of interleukin (IL)-4 and IL-10 remained unchanged. Histological examination revealed that mice administered OVA + rTsCstN were less likely to have inflammatory cell infiltration in their perivascular and peribronchial lung tissues than those administered OVA alone.

Conclusion

Recombinant T. spiralis novel cystatin demonstrated immunomodulatory effects to reduce severe pathogenic alterations in asthma mouse models, encouraging a viable alternative treatment for asthma and other immunoregulatory disorders in humans and animals in the future.

Gene Therapy for Immunoglobulin E, Complement-Mediated, and Eosinophilic Disorders

Immunoglobulin E, complement, and eosinophils play an important role in host defense, but dysfunction of each of these components can lead to a variety of human disorders. In this review, we summarize how investigators have adapted gene therapy and antisense technology to modulate immunoglobulin E, complement, and/or eosinophil levels to treat these disorders.

PRevalence of the Eosinophilic Phenotype Among SeveRE asthma patients in Lebanon: results of the PREPARE study

BACKGROUND

The prevalence of eosinophilic asthma in Lebanon, one of the most severe phenotypes among severe asthma, is not known. This study aimed at determining the prevalence of the eosinophilic phenotype defined as an eosinophil count ≥ 300 cells/mm3 among severe asthma patients in Lebanon.

METHODS

The Lebanese Chapter of the PREPARE study was a national, multicenter, cross-sectional observational study. Patients aged ≥ 12 years with severe asthma were identified and prospectively enrolled during clinic visits and completed the Global Initiative for Asthma (GINA) assessment of asthma control questionnaire. Patients' health characteristics were collected from medical records and blood samples were obtained for measurement of serum IgE levels and blood eosinophils count.

RESULTS

Overall, 101 patients (with mean age of 46.3 ± 17.0 years and 73.27% females) with severe asthma were included and, among them, 37% had eosinophilic phenotype, 67.3% had atopic phenotype with IgE > 100 IU/mL and 25.7% patients had overlapping atopic and eosinophilic phenotypes. Close to 80% had late-onset asthma, beyond 12 years of age, and around 85% had at least one severe exacerbation in the 12 months prior to study enrolment. The majority of participants [64.4%] had uncontrolled asthma, 24.7% had partially controlled symptoms and 10.9% had controlled symptoms. 19.8% of participants were on chronic oral corticosteroids, 78.2% had short course treatment of corticosteroids and all were prescribed a combination of inhaled corticosteroids and long-acting beta-agonist.

CONCLUSIONS

The majority of patients with severe asthma were uncontrolled of which 37% present with an eosinophilic phenotype, which should be taken into consideration for better management of these patients in view of the novel phenotype-specific therapeutic options.

Quercetin Alleviates Asthma-Induced Airway Inflammation and Remodeling through Downregulating Periostin via Blocking TGF-β1/Smad Pathway

INTRODUCTION

The aim of the study was to discuss whether the anti-asthmatic effect of quercetin is related to periostin and the downstream molecular pathway of quercetin's anti-asthmatic effect.

METHODS

We constructed asthmatic mice, sensitized by ovalbumin, and administrated different treatments into mice according to the experimental design. In this study, we mainly observed the inflammatory response, airway fibrosis, and airway hyperresponsiveness in asthmatic mice. Pathological stains (H&E, PAS, and Masson) were performed. We also detected the inflammation factors and fibrosis-related cytokines by enzyme-linked immunosorbent serologic assay. In addition, we also explored the level of periostin by enzyme-linked immunosorbent serologic assay and Western blot. At the same time, TGF-β1/Smad pathway was also determined by Western blot.

RESULTS

A high expression of periostin was found in asthmatic mice, and quercetin decreases periostin content in bronchoalveolar lavage fluid. Quercetin and OC-20 inhibit airway inflammation response, airway fibrosis, and airway hyperreactivity. Quercetin downregulated TGF-β1/Smad pathway in the lung tissues of asthmatic mice. Anti-asthma role of quercetin is related to periostin. Then deeper mechanical study revealed that inhibiting TGF-β1 could improve asthmatic symptoms, and quercetin exerted the protective effect on asthmatic mice through inhibition of TGF-β1/Smad pathway.

CONCLUSION

Quercetin provided a protective role against asthma via periostin, manifested by mild inflammatory infiltration, reduced goblet cell proliferation, and reduced airway fibrosis. TGF-β1/Smad pathway is an important transduction system, participating in the protective effect of quercetin on asthma.

Peripheral blood eosinophilia in adult asthmatic patients and its association with the severity of asthma

BACKGROUND

Asthma is a diverse disease with various etiologic bases. Severe asthma can be associated with increased mortality, hospitalization, and decreased quality of life for asthma patients. High blood eosinophil counts were associated with severe asthma, but recent studies have failed to confirm this as a marker of severe asthma among adult asthma patients. As a result, the purpose of this study was to determine the association between the severity of asthma and high blood eosinophil count.

METHODOLOGY

A simple random sampling technique was used to select 291 asthmatic patients for an institution-based cross-sectional study. Socio-demographic, behavioral, and clinical characteristics were collected by using a pre-tested structured questionnaire. Four milliliters of venous blood were collected from asthmatic patients for complete blood count and peripheral morphology assessment. The eosinophil count was analyzed by the Unicel DxH 800 (Beckman Coulter, Ireland) analyzer. A statistical package for social science version 20 (SPSS) software was used to analyze the data. The non-parametric (Mann-Whitney U) test was used to compare the eosinophil count with different background variables. A binary logistic regression analysis was used to assess the factors associated with eosinophilia. A p-value less than 0.05 in multivariable logistic regression analysis was considered statistically significant.

RESULT

In this study, the overall magnitude of eosinophilia was 19.6% (95% CI = 14.8-24.1). Being admitted to the emergency department (AOR = 0.25; 95% CI: 0.09-0.69, p = 0.007) and being female (AOR = 0.49; 95% CI: 0.26-0.9, p = 0.025) were shown to have a statistically significant association with eosinophilia. Moreover, the absolute eosinophil count was significantly higher among asthmatic patients infected with intestinal parasitic infection (p < 0.045).

CONCLUSION

Being female and admission to the emergency department were negatively associated with eosinophilia. Lack of eosinophilia can be related to the low-T2 asthma phenotype. The absolute eosinophil counts were higher among intestinal parasite-infected patients. Therefore, different biomarkers will be considered for the proper diagnosis and management of adult asthma patients.

Long-term effect of dupilumab on prevention of lung function decline in patients with uncontrolled moderate-to-severe asthma: ATLAS trial design

Background

Many patients with asthma experience loss of lung function over time, and in certain patients this can lead to progressive obstructive patterns similar to COPD. Patients with severe asthma may experience accelerated lung function decline (LFD). However, characteristics and risk factors for LFD in asthma have not been well described. Dupilumab may prevent or slow the rate of LFD in patients with uncontrolled, moderate-to-severe asthma. ATLAS trial is designed to evaluate the role of dupilumab in preventing/slowing LFD over a period of 3 years versus standard-of-care therapy.

Methods

ATLAS (clinicaltrials.gov identifier NCT05097287) is a randomised, double-blind, placebo-controlled, multicentre study that will include adult patients with uncontrolled moderate-to-severe asthma. ∼1828 patients will be randomised (2:1) to dupilumab 300 mg or placebo in combination with maintenance therapy every 2 weeks for 3 years. The primary objective is to assess the effect of dupilumab on preventing or slowing LFD by year 1 in the exhaled nitric oxide fraction (F _eNO) population (patients with F _eNO ≥35 ppb). The effect of dupilumab in slowing the rate of LFD by year 2 and year 3 in both F _eNO and total populations, exacerbations, asthma control, quality of life, biomarker changes and utility of F _eNO as a biomarker of LFD will also be evaluated.

Discussion

ATLAS is the first trial assessing the effect of a biologic on LFD, designed to establish the role of dupilumab in prevention of long-term loss of lung function and its potential effect on disease modification, which may provide unique insights into asthma pathophysiology, including predictive and prognostic factors of LFD.

C5aR1 activation in mice controls inflammatory eosinophil recruitment and functions in allergic asthma

BACKGROUND

Pulmonary eosinophils comprise at least two distinct populations of resident eosinophils (rEOS) and inflammatory eosinophils (iEOS), the latter recruited in response to pulmonary inflammation. Here, we determined the impact of complement activation on rEOS and iEOS trafficking and function in two models of pulmonary inflammation.

METHODS

BALB/c wild-type and C5ar1^-/- mice were exposed to different allergens or IL-33. Eosinophil populations in the airways, lung, or mediastinal lymph nodes (mLN) were characterized by FACS or immunohistochemistry. rEOS and iEOS functions were determined in vivo and in vitro.

RESULTS

HDM and IL-33 exposure induced a strong accumulation of iEOS but not rEOS in the airways, lungs, and mLNs. rEOS and iEOS expressed C3/C5 and C5aR1, which were significantly higher in iEOS. Initial pulmonary trafficking of iEOS was markedly reduced in C5ar1^-/- mice and associated with less IL-5 production from ILC2 cells. Functionally, adoptively transferred pulmonary iEOS from WT but not from C5ar1^-/- mice-induced airway hyperresponsiveness (AHR), which was associated with significantly reduced C5ar1^-/- iEOS degranulation. Pulmonary iEOS but not rEOS were frequently associated with T cells in lung tissue. After HDM or IL-33 exposure, iEOS but not rEOS were found in mLNs, which were significantly reduced in C5ar1^-/- mice. C5ar1^-/- iEOS expressed less costimulatory molecules, associated with a decreased potency to drive antigen-specific T cell proliferation and differentiation into memory T cells.

CONCLUSIONS

We uncovered novel roles for C5aR1 in iEOS trafficking and activation, which affects key aspects of allergic inflammation such as AHR, ILC2, and T cell activation.

From Beneath the Skin to the Airway Wall: Understanding the Pathological Role of Adipose Tissue in Comorbid Asthma-Obesity

This article provides a contemporary report on the role of adipose tissue in respiratory dysfunction. Adipose tissue is distributed throughout the body, accumulating beneath the skin (subcutaneous), around organs (visceral), and importantly in the context of respiratory disease, has recently been shown to accumulate within the airway wall: "airway-associated adipose tissue." Excessive adipose tissue deposition compromises respiratory function and increases the severity of diseases such as asthma. The mechanisms of respiratory impairment are inflammatory, structural, and mechanical in nature, vary depending on the anatomical site of deposition and adipose tissue subtype, and likely contribute to different phenotypes of comorbid asthma-obesity. An understanding of adipose tissue-driven pathophysiology provides an opportunity for diagnostic advancement and patient-specific treatment. As an exemplar, the potential impact of airway-associated adipose tissue is highlighted, and how this may change the management of a patient with asthma who is also obese. © 2023 American Physiological Society. Compr Physiol 13:4321-4353, 2023.

Super resolution microscopy analysis reveals increased Orai1 activity in asthma and cystic fibrosis lungs

QUESTION

In diseases such as asthma and cystic fibrosis (CF), the immune response is dysregulated and the lung is chronically inflamed. Orai1 activation is required for the initiation and persistence of inflammation. However, Orai1 expression in the lung is poorly understood. We therefore tested the hypothesis that Orai1 expression was upregulated in asthmatic and CF lungs.

MATERIALS AND METHODS

We used LungMAP to analyze single-cell RNAseq data of Orai1 and stromal interaction molecule 1 (STIM1) expression in normal human lungs. We then performed RNAscope analysis and immunostaining on lung sections from normal, asthma, and CF donors. We imaged sections by confocal and super resolution microscopy, and analyzed Orai1 and STIM1 expression in different pulmonary cell types.

RESULTS

Orai1 was broadly-expressed, but expression was greatest in immune cells. At mRNA and protein levels, there were no consistent trends in expression levels between the three phenotypes. Orai1 must interact with STIM1 in order to activate and conduct Ca2+. We therefore used STIM1/Orai1 co-localization as a marker of Orai1 activity. Using this approach, we found significantly increased co-localization between these proteins in epithelia, interstitial and luminal immune cells, but not alveoli, from asthma and CF lungs. Orai1 also aggregates as part of its activation process. Using super resolution microscopy, we also found significantly increased Orai1 aggregation in immune cells from asthmatic and CF lungs.

CONCLUSION

We found evidence that Orai1 was more active in asthma and CF than normal lungs. These data suggest that Orai1 is a relevant target for reducing pulmonary inflammation.

The Role of Staphylococcus aureus and Its Toxins in the Pathogenesis of Allergic Asthma

Bronchial asthma is one of the most common chronic diseases worldwide and affects more than 300 million patients. Allergic asthma affects the majority of asthmatic children as well as approximately 50% of adult asthmatics. It is characterized by a Th2-mediated immune response against aeroallergens. Many aspects of the overall pathophysiology are known, while the underlying mechanisms and predisposing factors remain largely elusive today. Over the last decade, respiratory colonization with Staphylococcus aureus (S. aureus), a Gram-positive facultative bacterial pathogen, came into focus as a risk factor for the development of atopic respiratory diseases. More than 30% of the world’s population is constantly colonized with S. aureus in their nasopharynx. This colonization is mostly asymptomatic, but in immunocompromised patients, it can lead to serious complications including pneumonia, sepsis, or even death. S. aureus is known for its ability to produce a wide range of proteins including toxins, serine-protease-like proteins, and protein A. In this review, we provide an overview of the current knowledge about the pathophysiology of allergic asthma and to what extent it can be affected by different toxins produced by S. aureus. Intensifying this knowledge might lead to new preventive strategies for atopic respiratory diseases.

Identification of Two Eosinophil Subsets in Induced Sputum from Patients with Allergic Asthma According to CD15 and CD66b Expression

Two subsets of eosinophils have been described: resident eosinophils with homeostatic functions (rEOS) in healthy subjects and in patients with nonallergic eosinophilic asthma, and inflammatory eosinophils (iEOS) in blood and lung samples from patients with allergic asthma. We explored if it would be possible to identify different subsets of eosinophils using flow cytometry and the gating strategy applied to induced sputum. We conducted an observational cross-sectional single-center study of 62 patients with persistent allergic asthma. Inflammatory cells from induced sputum samples were counted by light microscopy and flow cytometry, and cytokine levels in the supernatant were determined. Two subsets of eosinophils were defined that we call E1 (CD66b-high and CD15-high) and E2 (CD66b-low and CD15-low). Of the 62 patients, 24 were eosinophilic, 18 mixed, 10 paucigranulocytic, and 10 neutrophilic. E1 predominated over E2 in the eosinophilic and mixed patients (20.86% vs. 6.27% and 14.42% vs. 4.31%, respectively), while E1 and E2 were similar for neutrophilic and paucigranulocytic patients. E1 correlated with IL-5, fractional exhaled nitric oxide, and blood eosinophils. While eosinophil subsets have been identified for asthma in blood, we have shown that they can also be identified in induced sputum.

Anatabine attenuates ovalbumin-induced asthma via oxidative stress and inflammation mitigation and Nrf2/HO-1 signaling upregulation in rats

AIMS

Asthma affects a large number of people worldwide and is characterized by chronic allergic airway inflammation. Anatabine is a natural alkaloid that is structurally similar to nicotine and found in the Solanaceae family of plants, with anti-inflammatory properties. Consequently, this study aimed to evaluate the potential therapeutic effect of anatabine against asthma.

MAIN METHODS

Ovalbumin was used to induce asthma in rats. Two asthmatic groups were treated with low and high doses of anatabine.

KEY FINDINGS

Asthmatic animals experienced increased total leukocyte count and inflammatory cytokines in bronchoalveolar lavage fluid (BALF), bronchitis, and bronchopneumonia associated with mast cell infiltration. Additionally, inducible nitric oxide synthase immunostaining was observed, with decreased pulmonary antioxidant capacity and enzymes and decreased Nrf2 and HO-1 gene expression while increased NFκB-P65 expression. Interestingly, asthmatic animals treated with anatabine at both doses showed dose-dependently decreased inflammatory cells and cytokine levels within BALF reduced inflammation in the airways through decreased mast cell infiltration within lung tissues and increased antioxidant enzymes and Nrf2 and Ho-1 expression levels.

SIGNIFICANCE

Our results highlight the potential beneficial effect of anatabine against asthma through anti-inflammatory and antioxidant mechanisms. Therefore, anatabine is a promising candidate for pulmonary asthma treatment.

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.

Prevalence of the eosinophilic phenotype among severe asthma patients in Brazil: the BRAEOS study

Objective:

To assess the prevalence of the eosinophilic and allergic phenotypes of severe asthma in Brazil, as well as to investigate the clinical characteristics of severe asthma patients in the country.

Methods:

This was a cross-sectional study of adult patients diagnosed with severe asthma and managed at specialized centers in Brazil. The study was conducted in 2019.

Results:

A total of 385 patients were included in the study. Of those, 154 had a blood eosinophil count > 300 cells/mm³ and 231 had a blood eosinophil count of ≤ 300 cells/mm³. The median age was 54.0 years, and most of the patients were female, with a BMI of 29.0 kg/m² and a history of allergy (81.6%). The prevalence of patients with a blood eosinophil count > 300 cells/mm³ was 40.0% (95% CI: 35.1-44.9), and that of those with a blood eosinophil count > 300 cells/mm³ and a history of allergy was 31.9% (95% CI: 27.3-36.6). Age and BMI showed positive associations with a blood eosinophil count > 300 cells/mm³ (OR = 0.97, p < 0.0001; and OR = 0.96, p = 0.0233, respectively), whereas the time elapsed since the onset of asthma symptoms showed an increased association with a blood eosinophil count > 300 cells/mm³ (OR = 1.02, p = 0.0011).

Conclusions:

This study allowed us to characterize the population of severe asthma patients in Brazil, showing the prevalence of the eosinophilic phenotype (in 40% of the sample). Our results reveal the relevance of the eosinophilic phenotype of severe asthma at a national level, contributing to increased effectiveness in managing the disease and implementing public health strategies.

Selected hematological abnormalities and their associated factors among asthmatic patients in Northwest Ethiopia: a cross-sectional study

Background

Asthma is a chronic inflammatory disease that affects the lungs. Variation in whole blood cell lines is caused by the progression and severity of asthma. Common hematological abnormalities encountered during asthma include eosinophilia, neutrophilia, leukocytosis, and increased erythrocyte sedimentation rate. The main aim of this study was to assess the selected hematological abnormalities and their associated factors among asthmatic patients in Northwest Ethiopia from March to May 2021.

Methodology

A hospital-based cross-sectional study was conducted on a total of 320 asthmatic patients in Northwest Ethiopia. A simple random sampling technique was employed to select study participants. A pre-tested structured questionnaire and a checklist were used to collect data. Blood samples were collected from asthmatic patients for complete blood count and erythrocyte sedimentation rate determination. Hematological profiles were analyzed by Unicel DxH 800 (Beckman Coulter, Ireland). The erythrocyte sedimentation rate was determined by using the Westergren method. The data were entered into EpiData version 3.0.4 and analyzed with a statistical package for social science version 20 software. The bi-variable and multi-variable binary logistic regression models were used to assess the factors associated with hematological abnormalities. A p value of less than 0.05 in the multivariable logistic regression analysis was considered statistically significant.

Results

The overall prevalence of neutrophilia, eosinophilia, thrombocytopenia, leukocytosis, and basophilia was 35.3%, 20%, 11.9%, 10.3%, and 4.1%, respectively. Neutrophilia was associated with a lack of physical activity (AOR = 3.25; 95% CI 1.43–7.37) and a history of taking non-asthmatic drugs within the previous three months (AOR = 2.63; 95% CI 1.22–5.65). Being admitted to the emergency department (AOR = 0.27; 95% CI 0.11–5.67) was found to be associated with eosinophilia. In addition, being admitted to the emergency department (AOR = 5.44; 95%CI: 2.6–11.3) was associated with thrombocytopenia.

Conclusion

The current study demonstrated the predominant prevalence of neutrophilia, followed by eosinophilia, among asthma patients. Therefore, hematological abnormalities should be taken into account for proper monitoring and management of asthmatic patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-02020-z.

Title-Inflammatory Signaling Pathways in Allergic and Infection-Associated Lung Diseases

Lung inflammation can be caused by pathogen infection alone or by allergic disease, leading to pneumonitis. Most of the allergens (antigens) that cause allergic lung diseases, including asthma and hypersensitivity pneumonitis (HP), are derived from microorganisms, such as bacteria, viruses, and fungi, but some inorganic materials, such as mercury, can also cause pneumonitis. Certain allergens, including food and pollen, can also cause acute allergic reactions and lead to lung inflammation in individuals predisposed to such reactions. Pattern recognition-associated and damage-associated signaling by these allergens can be critical in determining the type of hypersensitization and allergic disease, as well as the potential for fibrosis and irreversible lung damage. This review discusses the signs, symptoms, and etiology of allergic asthma, and HP. Furthermore, we review the immune response and signaling pathways involved in pneumonitis due to both microbial infection and allergic processes. We also discuss current and potential therapeutic interventions for infection-associated and allergic lung inflammation.

Asthmatic Eosinophils Alter the Gene Expression of Extracellular Matrix Proteins in Airway Smooth Muscle Cells and Pulmonary Fibroblasts

The impaired production of extracellular matrix (ECM) proteins by airway smooth muscle cells (ASMC) and pulmonary fibroblasts (PF) is a part of airway remodeling in asthma. This process might be influenced by eosinophils that migrate to the airway and abundantly secrete various cytokines, including TGF-β. We aimed to investigate the effect of asthmatic eosinophils on the gene expression of ECM proteins in ASMC and PF. A total of 34 study subjects were recruited: 14 with allergic asthma (AA), 9 with severe non-allergic eosinophilic asthma (SNEA), and 11 healthy subjects (HS). All AA patients underwent bronchial allergen challenge with D. pteronyssinus. The peripheral blood eosinophils were isolated using high-density centrifugation and magnetic separation. The individual cell cultures were made using hTERT ASMC and MRC-5 cell lines and the subjects’ eosinophils. The gene expression of ECM and the TGF-β signaling pathway was analyzed using qRT-PCR. We found that asthmatic eosinophils significantly promoted collagen I, fibronectin, versican, tenascin C, decorin, vitronectin, periostin, vimentin, MMP-9, ADAM33, TIMP-1, and TIMP-2 gene expression in ASMC and collagen I, collagen III, fibronectin, elastin, decorin, MMP-2, and TIMP-2 gene expression in PF compared with the HS eosinophil effect. The asthmatic eosinophils significantly increased the gene expression of several canonical and non-canonical TGF-β signaling pathway components in ASMC and PF compared with the HS eosinophil effect. The allergen-activated AA and SNEA eosinophils had a greater effect on these changes. In conclusion, asthmatic eosinophils, especially SNEA and allergen-activated eosinophils, imbalanced the gene expression of ECM proteins and their degradation-regulating proteins. These changes were associated with increased gene expression of TGF-β signaling pathway molecules in ASMC and PF.

RSV Infection in Neonatal Mice Induces Pulmonary Eosinophilia Responsible for Asthmatic Reaction

Respiratory syncytial virus (RSV) is a leading cause of lower respiratory tract infections in infants and young children. Severe respiratory viral infection in early life is intimately associated with childhood recurrent wheezing and is a risk factor for asthma later in life. Although eosinophilic airway inflammation is an important trait in asthma of children, the roles of pulmonary eosinophils in the disease have been inadequately understood. Here, we show that RSV infection in neonatal mice causes eosinophilia after allergen stimulation. We showed that RSV infection in neonatal mice exacerbated allergic asthma to allergen stimulation that was accompanied with increased detection of eosinophils in the lungs. In addition, we also detected accumulation of ILC2, CD4⁺ T cells, and macrophages. Importantly, adoptive transfer of eosinophils from asthmatic mice with early-life RSV infection exacerbated pulmonary pathologies associated with allergic respiratory inflammation in naive mice in response to foreign antigen. The induction of asthmatic symptoms including AHR, tracheal wall thickening, and mucus production became more severe after further stimulation in those mice. The expression of antigen presentation-related molecules like CD80, CD86, and especially MHC II was markedly induced in eosinophils from OVA-stimulated asthmatic mice. The accumulation of CD4⁺ T cells in the lungs was also significantly increased as a result of adoptive transfer of eosinophils. Importantly, the deterioration of lung pathology caused by adoptive transfer could be effectively attenuated by treatment with indomethacin, a nonsteroidal anti-inflammatory drug. Our findings highlight the significance of eosinophil-mediated proinflammatory response in allergic disease associated with early-life infection of the respiratory tract.

Jing Si Herbal Drink as a prospective adjunctive therapy for COVID-19 treatment: Molecular evidence and mechanisms

Background

SARS-CoV-2 has led to a sharp increase in the number of hospitalizations and deaths from pneumonia and multiorgan disease worldwide; therefore, SARS-CoV-2 has become a global health problem. Supportive therapies remain the mainstay treatments against COVID-19, such as oxygen inhalation, antiviral drugs, and antibiotics. Traditional Chinese medicine (TCM) has been shown clinically to relieve the symptoms of COVID-19 infection, and TCMs can affect the pathogenesis of SARS-CoV-2 infection in vitro. Jing Si Herbal Drink (JSHD), an eight herb formula jointly developed by Tzu Chi University and Tzu Chi Hospital, has shown potential as an adjuvant treatment for COVID-19 infection. A randomized controlled trial (RCT) of JSHD as an adjuvant treatment in patients with COVID-19 infection is underway

Objectives

This article aims to explore the efficacy of the herbs in JSHD against COVID-19 infection from a mechanistic standpoint and provide a reference for the rational utilization of JSHD in the treatment of COVID-19.

Method

We compiled evidence of the herbs in JSHD to treat COVID-19 in vivo and in vitro.

Results

We described the efficacy and mechanism of action of the active ingredients in JSHD to treat COVID-19 based on experimental evidence. JSHD includes 5 antiviral herbs, 7 antioxidant herbs, and 7 anti-inflammatory herbs. In addition, 2 herbs inhibit the overactive immune system, 1 herb reduces cell apoptosis, and 1 herb possesses antithrombotic ability.

Conclusion

Although experimental data have confirmed that the ingredients in JSHD are effective against COVID-19, more rigorously designed studies are required to confirm the efficacy and safety of JSHD as a COVID-19 treatment.

Prevalence of eosinophilic, atopic, and overlap phenotypes among patients with severe asthma in Saudi Arabia: a cross-sectional study

Background

Eosinophilia is a significant factor in asthma severity; however, the prevalence of severe eosinophilic asthma in Saudi Arabia is largely unknown. We aimed to determine the prevalence of the eosinophilic (defined in this study as ≥ 300 cells/mm³ in blood), atopic (atopic phenotype 1, defined in this study as > 100 IU/mL total serum IgE; atopic phenotype 2, defined in this study as > 150 IU/mL), and overlap phenotypes among patients with severe asthma in Saudi Arabia.

Methods

A cross-sectional study was conducted in centers specialized in severe asthma management. Patients aged ≥ 12 years with severe asthma were enrolled. Study patients responded to the Global Initiative for Asthma 2018 assessment of asthma control questionnaire and provided study investigators with current information related to the study objectives. Additional medical record data and a blood sample for total serum IgE and complete blood count were collected.

Results

A total of 101 patients were enrolled; 83% were female and the mean (standard deviation) age was 48.7 (13.2) years. Forty-five (45%) patients had the eosinophilic phenotype, 50 (50%) had atopic phenotype 1, and 25 (25%) had phenotypic overlap (eosinophilic and atopic 1). Forty-one (41%) patients had atopic phenotype 2 and 23 (23%) had phenotypic overlap (eosinophilic and atopic 2). Asthma control and oral corticosteroid use patterns were similar and there were no significant differences in number of asthma exacerbations across phenotypes.

Conclusions

In Saudi Arabia, 45% of patients with severe asthma had the eosinophilic phenotype, which is most likely an underestimation as no clinical features of eosinophilia were taken into account in the definition of eosinophilia. Approximately half of them had phenotypic overlap with the atopic phenotype.

Trial registration NCT03931954; ClinicalTrials.gov, April 30, 2019.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01856-9.

A SPLUNC1 Peptidomimetic Inhibits Orai1 and Reduces Inflammation in a Murine Allergic Asthma Model

Orai1 is a plasma membrane Ca2+ channel that mediates store operated Ca2+ entry (SOCE) and regulates inflammation. Short palate lung and nasal epithelial clone 1 (SPLUNC1) is an asthma gene modifier which inhibits Orai1/SOCE via its C-terminal α6 region. SPLUNC1 levels are diminished in asthma patient airways. Thus, we hypothesized that inhaled α6 peptidomimetics could inhibit Orai1 and reduce airway inflammation in a murine asthma model. To evaluate α6-Orai1 interactions, we used fluorescent assays to measure Ca2+ signalling, Förster resonance energy transfer (FRET), fluorescent recovery after photobleaching, immunostaining, total internal reflection (TIRF) microscopy and Western blotting. To test whether α6 peptidomimetics inhibited SOCE and decreased inflammation in vivo, wild-type and SPLUNC1-/- mice were exposed to house dust mite (HDM) extract ± α6 peptide. We also performed nebulization, jet milling and scanning electron microscopy to evaluate α6 for inhalation. SPLUNC1-/- mice had an exaggerated response to HDM. In bronchoalveolar lavage (BAL)-derived immune cells, Orai1 levels increased after HDM exposure in SPLUNC1-/- but not wild-type mice. Inhaled α6 reduced Orai1 levels in mice regardless of genotype. In HDM-exposed mice, α6 dose-dependently reduced eosinophilia and neutrophilia. In vitro, α6 inhibited SOCE in multiple immune cell types and α6 could be nebulized or jet milled without loss of function. These data suggest that α6 peptidomimetics may be a novel, effective anti-inflammatory therapy for asthma patients.

Purified Native and Recombinant Major Alternaria alternata Allergen (Alt a 1) Induces Allergic Asthma in the Murine Model

Aeroallergens such us the spores of Alternaria alternata are described as the most important agents associated with respiratory allergies and severe asthma. Various experimental models of asthma have been developed using A. alternata extracts to study the pathogenesis of asthma, establishing the main parameters that trigger the asthmatic response. In this study, we describe a mouse model of asthma induced only by Alt a 1. To induce the allergic response, mice were challenged intranasally with the major allergen of A. alternata, Alt a 1. The presence of eosinophils in the lungs, elevated concentrations of Th2 family cytokines, lymphocyte proliferation and elevated IgE total serum levels indicated that the sensitisation and challenge with Alt a 1 induced the development of airway inflammation. Histological studies showed an eosinophilic cellular infiltrate in the lung tissue of mice instilled with Alt a 1. We demonstrate that Alt a 1 alone is capable of inducing a lung inflammatory response with an increase in IgE serum levels mimicking the allergic asthma immunoresponse when it is administered into BALB/c mice. This model will allow the evaluation of the immunoregulatory or immunotolerant capacity of several molecules that can be used in targeted immunotherapy for fungal allergic asthma.

Investigation of antinociceptive, antipyretic, antiasthmatic, and spasmolytic activities of Brazilian Cannabis sativa L. roots in rodents

ETHNOPHARMACOLOGICAL RELEVANCE

Many studies are performed with the aerial parts of Cannabis sativa L. (Cannabaceae). However, roots remain poorly studied, despite citations in the scientific literature. The C. sativa roots are indicated for the treatment of pain, inflammation, fever, among other health problems.

AIM OF THE STUDY

This study aimed to evaluate the antinociceptive, antipyretic, antiasthmatic, and spasmolytic activities of C. sativa roots in experimental models using mice and rats.

MATERIAL AND METHODS

The chemical composition of the aqueous extract of C. sativa roots (AECsR) was evaluated by LC-MS. The antinociceptive activity was assessed in mice by the induction of writhing with acetic acid, paw licking with formalin, and reactivity in the hot plate test. Fever was induced by the administration of a suspension of Saccharomyces cerevisiae in young rats. The asthmatic activity was performed with ovalbumin (OVA)-immunized mice with cellular and histological analysis. Finally, the spasmolytic activity was performed using mice isolated trachea. For in vivo studies, the doses were 12.5, 25, or 50 mg/kg whereas for in vitro, the concentration of AECsR was 729 μg/mL.

RESULTS

From the LC-MS data, we identified p-coumaroyltyramine, feruloyltyramine canabissativine in AECsR. The extract promoted a reduction of writhing in all tested doses (12.5, 25, or 50 mg/kg). Similarly, it reduced the pain in the formalin test at doses of 12.5 and 50 mg/kg (first phase) and 12.5 and 25 mg/kg (second phase). In the hot plate test, the doses of 12.5, 25, and 50 mg/kg promoted antinociceptive effect at different times, and the lowest dose maintained its action in the analyzes performed at 60, 90, and 120 min after administration. The anti-inflammatory activity of AECsR was observed in the mouse model of asthma, reducing the total leukocyte count in the bronchoalveolar fluid (BALF) at a dose of 25 mg/kg, as well as reducing eosinophilia in all tested doses (12.5, 25, and 50 mg/kg). Histological analysis of lungs stained with H&E and PAS showed a reduction in the number of inflammatory cells in the perivascular and peribronchial region, as well as reduced mucus production.

CONCLUSION

The results suggest that AECsR promotes pain control, either by a central or inflammatory mechanism, and has antiasthmatic activity. However, there was no antipyretic or spasmolytic effect.

Ding Chuan Tang Attenuates Airway Inflammation and Eosinophil Infiltration in Ovalbumin-Sensitized Asthmatic Mice

Asthma is a T helper 2 (Th2) cell-associated chronic inflammatory diseases characterized with airway obstruction, increased mucus production, and eosinophil infiltration. Conventional medications for asthma treatment cannot fully control the symptoms, and potential side effects are also the concerns. Thus, complement or alternative medicine (CAM) became a new option for asthma management. Ding Chuan Tang (DCT) is a traditional Chinese herbal decoction applied mainly for patients with coughing, wheezing, chest tightness, and asthma. Previously, DCT has been proved to improve children airway hyperresponsiveness (AHR) in a randomized and double-blind clinical trial. However, the mechanisms of how DCT alleviates AHR remain unclear. Since asthmatic features such as eosinophil infiltration, IgE production, and mucus accumulation are relative with Th2 responses, we hypothesized that DCT may attenuate asthma symptoms through regulating Th2 cells. Ovalbumin (OVA) was used as a stimulant to sensitize BALB/c mice to establish an asthmatic model. AHR was detected one day before sacrifice. BALF and serum were collected for immune cell counting and antibody analysis. Splenocytes were cultured with OVA in order to determine Th2 cytokine production. Lung tissues were collected for histological and gene expression analyses. Our data reveal that DCT can attenuate AHR and eosinophil accumulation in the 30-day sensitization asthmatic model. Histological results demonstrated that DCT can reduce cell infiltration and mucus production in peribronchial and perivascular site. In OVA-stimulated splenocyte cultures, a significant reduction of IL-5 and IL-13 in DCT-treated mice suggests that DCT may alleviate Th2 responses. In conclusion, the current study demonstrates that DCT has the potential to suppress allergic responses through the reduction of mucus production, eosinophil infiltration, and Th2 activity in asthma.

Could the Epigenetics of Eosinophils in Asthma and Allergy Solve Parts of the Puzzle?

Epigenetics is a field of study investigating changes in gene expression that do not alter the DNA sequence. These changes are often influenced by environmental or social factors and are reversible. Epigenetic mechanisms include DNA methylation, histone modification, and noncoding RNA. Understanding the role of these epigenetic mechanisms in human diseases provides useful information with regard to disease severity and development. Several studies have searched for the epigenetic mechanisms that regulate allergies and asthma; however, only few studies have used samples of eosinophil, a proinflammatory cell type known to be largely recruited during allergic or asthmatic inflammation. Such studies would enable us to better understand the factors that influence the massive recruitment of eosinophils during allergic and asthmatic symptoms. In this review, we sought to summarize different studies that aimed to discover differential patterns of histone modifications, DNA methylation, and noncoding RNAs in eosinophil samples of individuals with certain diseases, with a particular focus on those with asthma or allergic diseases.

Understanding the key issues in the treatment of uncontrolled persistent asthma with type 2 inflammation

Asthma is a complex respiratory disease that varies in severity and response to treatment. Several asthma phenotypes with unique clinical and inflammatory characteristics have been identified. Endotypes, based on distinct molecular profiles, help to further elucidate the heterogeneity within asthma. Type 2 inflammation, involving both the innate (type 2 innate lymphoid cell) and adaptive (T-helper type 2 cells) immune systems, underpins the complex pathophysiology of chronic inflammation in asthma, as well as the presence of comorbid disease (e.g. chronic rhinosinusitis with nasal polyps, allergic rhinitis and atopic dermatitis). Type 2 inflammation is characterised by upregulation of the type 2 cytokines interleukin (IL)-4, IL-5 and IL-13, IgE-mediated release of immune mediators and dysfunction of epithelial or epidermal barriers. Targeting these key proximal type 2 cytokines has shown efficacy in recent studies adopting a personalised approach to treatment using targeted biologics. Elevated levels of biomarkers downstream of type 2 cytokines, including fractional exhaled nitric oxide, serum IgE and blood and sputum eosinophils, have been linked to mechanisms involved in type 2 inflammation. They have the potential to aid diagnosis, and to predict and monitor response to treatment. The objective of this review is to summarise the current understanding of the biology of type 2 inflammation in asthma, examine its influence on type 2 inflammatory comorbidities, and discuss how type 2 inflammatory biomarkers can be harnessed to further personalise treatments in the age of biologic medicines.

This review covers the pathophysiology of type 2 inflammation in asthma, its influence on type 2 comorbidities, and ways in which type 2 biomarkers can be harnessed to improve diagnosis and further personalise treatments in the age of biologic medicineshttps://bit.ly/2MSOI2O

Digital Imaging Analysis Reveals Reduced Alveolar α-Smooth Muscle Actin Expression in Severe Asthma

Expansion of α-smooth muscle actin (α-SMA)-expressing airway smooth muscle of the large airways in asthma is well-studied. However, the contribution of α-SMA-expressing cells in the more distal alveolated parenchyma, including pericytes and myofibroblasts within the alveolar septum, to asthma pathophysiology remains relatively unexplored. The objective of this study was to evaluate α-SMA expression in the alveolated parenchyma of individuals with severe asthma (SA), compared with healthy controls or individuals with chronic obstructive pulmonary disease. Using quantitative digital image analysis and video-assisted thoracoscopic surgery lung biopsies, we show that alveolated parenchyma α-SMA expression is markedly reduced in SA in comparison to healthy controls (mean %positive pixels: 12% vs. 23%, P=0.005). Chronic obstructive pulmonary disease cases showed a similar, but trending, decrease in α-SMA positivity compared with controls (mean %positivity: 17% vs. 23%, P=0.107), which may suggest loss of α-SMA expression is a commonality of obstructive lung diseases. The SA group had similar staining for ETS-related gene protein, a specific endothelial marker, comparatively to controls (mean %positive nuclei: 34% vs. 42%, P=0.218), which suggests intact capillary endothelium and likely intact capillary-associated, α-SMA-positive pericytes. These findings suggest that the loss of α-SMA expression in SA may be because of changes in myofibroblast α-SMA expression or cell number. Further study is necessary to fully evaluate possible mechanisms and consequences of this phenomenon.

Gentiopicroside ameliorates ovalbumin-induced airway inflammation in a mouse model of allergic asthma via regulating SIRT1/NF-κB signaling pathway

Allergic asthma is a common airway inflammatory disorder with increasing morbidity and mortality worldwide. Gentiopicroside (GPS) is a secoiridoid glycoside compound that exhibits anti-inflammatory property. However, the effect of GPS on allergic asthma has not been reported yet. In this study, we investigated the role of GPS in a mouse model of ovalbumin (OVA)-induced allergic asthma and explored its potential mechanism. Mice were sensitized with OVA and gavaged with 20, 40, or 80 mg/kg GPS. Administration of GPS decreased lung wet-to-dry weight ratio. Histological analysis of H&E and PAS staining showed that GPS treatment alleviated inflammatory cell infiltration and goblet cell hyperplasia in lung tissue of OVA-sensitized mice. Moreover, GPS inhibited the recruitment of inflammatory cells including total cells, macrophages, eosinophils, lymphocytes and neutrophils and the secretion of T helper type 2 (Th2) cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) of OVA-sensitized mice in a dose dependent manner. The levels of OVA-specific immunoglobulin E (IgE) and pro-inflammatory tumor necrosis factor (TNF)-α were also attenuated by GPS treatment. Interestingly, GPS upregulated the expression of silent information regulator 1 (SIRT1) while downregulated the expression of acetyl-nuclear factor kappa B (NF-κB) p65 in lung tissue of OVA-sensitized mice. Furthermore, treatment with an SIRT1 inhibitor (EX-527) partially abolished the inhibitory effect of GPS on OVA-induced airway inflammation, suggesting that the anti-inflammation of GPS might be achieved through regulating SIRT1/NF-κB p65 signaling pathway. These findings indicate that GPS might be a novel drug candidate in the treatment of allergic asthma.

Unraveling the thread of uncontrolled immune response in COVID-19 and STEMI: an emerging need for knowledge sharing

The outbreak of severe acute respiratory syndrome coronavirus 2 that first emerged in Wuhan in December 2019 has resulted in the devastating pandemic of coronavirus disease 2019, creating an emerging need for knowledge sharing. Meanwhile, myocardial infarction is and will probably remain the foremost cause of death in the Western world throughout the coming decades. Severe deregulation of the immune system can unnecessarily expand the inflammatory response and participate in target and multiple organ failure, in infection but also in critical illness. Indeed, the course and fate of inflammatory cells observed in severe ST-elevation myocardial infarction (neutrophilia, monocytosis, and lymphopenia) almost perfectly mirror those recently reported in severe coronavirus disease 2019. A pleiotropic proinflammatory imbalance hampers adaptive immunity in favor of uncontrolled innate immunity and is associated with poorer structural and clinical outcomes. The goal of the present review is to gain greater insight into the cellular and molecular mechanisms underlying this canonical activation and downregulation of the two arms of the immune response in both entities, to better understand their pathophysiology and to open the door to innovative therapeutic options. Knowledge sharing can pave the way for therapies with the potential to significantly reduce mortality in both infectious and noninfectious scenarios.

Targeted therapy in eosinophilic chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common and preventable airway disease causing significant worldwide mortality and morbidity. Lifetime exposure to tobacco smoking and environmental particles are the two major risk factors. Over recent decades, COPD has become a growing public health problem with an increase in incidence. COPD is defined by airflow limitation due to airway inflammation and small airway remodelling coupled to parenchymal lung destruction. Most patients exhibit neutrophil-predominant airway inflammation combined with an increase in macrophages and CD8⁺ T-cells. Asthma is a heterogeneous chronic inflammatory airway disease. The most studied subtype is type 2 (T2) high eosinophilic asthma, for which there are an increasing number of biologic agents developed. However, both asthma and COPD are complex and share common pathophysiological mechanisms. They are known as overlapping syndromes as approximately 40% of patients with COPD present an eosinophilic airway inflammation. Several studies suggest a putative role of eosinophilia in lung function decline and COPD exacerbation. Recently, pharmacological agents targeting eosinophilic traits in uncontrolled eosinophilic asthma, especially monoclonal antibodies directed against interleukins (IL-5, IL-4, IL-13) or their receptors, have shown promising results. This review examines data on the rationale for such biological agents and assesses efficacy in T2-endotype COPD patients.

Patients with severe COPD and eosinophilic inflammation experience uncontrolled symptoms despite optimal pharmaceutical treatment. The development of new biomarkers is needed for better phenotyping of patients to propose innovative targeted therapy.https://bit.ly/2KzWuNO

Overlap of allergic, eosinophilic and type 2 inflammatory subtypes in moderate-to-severe asthma

Background

Current biologic therapies target allergic, eosinophilic or type 2 inflammation phenotypic asthma. However, frequency and degree of overlap among these subtypes is unclear.

Objective

To characterize overlap among allergic, eosinophilic and type 2 asthma phenotypes.

Methods

Post hoc analyses of baseline data were performed in two adult populations: (a) not selected for any asthma subtype (N = 935) and (b) selected for allergic asthma (N = 1049). Degree of overlap was examined using commonly accepted phenotypic definitions to guide treatment for allergic asthma (skin prick–positive and/or positive serum–specific immunoglobulin E > 0.35 kU/L) and eosinophilic asthma (blood eosinophil high count ≥ 300 cells/µL; low cut‐off ≥ 150 cells/µL). Consistent with previous studies, fractional exhaled nitric oxide high level of ≥ 35 ppb and low cut‐off of ≥ 25 ppb were selected as local markers of type 2 inflammation and to prevent overlap with the systemic eosinophilic asthma definition.

Results

In the non‐subtype–selected population, 78.0% had allergic asthma; of these, 39.5% had eosinophilic asthma and 29.5% had type 2 asthma. Within patients with eosinophilic asthma (40.6% of total), 75.8% had allergic asthma and 41.3% had type 2 asthma. Within patients with type 2 asthma (28.3% of total), 81.1% had allergic asthma and 59.2% had eosinophilic asthma. In the allergic asthma–selected population, 38.3% had eosinophilic asthma and 29.2% had type 2 asthma. Within patients with eosinophilic asthma, 46.3% had type 2 asthma. Within patients with type 2 asthma, 60.8% had eosinophilic asthma. Overlaps among subtypes increased at low cut‐off values.

Conclusions and clinical relevance

In this post hoc analysis in adults with moderate‐to‐severe asthma, allergic asthma was the most prevalent phenotype, followed by eosinophilic and type 2 asthma. Despite observed overlaps, a considerable proportion of patients had only a predominantly allergic subtype. Understanding the degree of overlap across phenotypes will help patient management and guide treatment options.

Assessing the Respiratory Effects of Air Pollution from Biomass Cookstoves on Pregnant Women in Rural India

Background: In India, biomass fuel is burned in many homes under inefficient conditions, leading to a complex milieu of particulate matter and environmental toxins known as household air pollution (HAP). Pregnant women are particularly vulnerable as they and their fetus may suffer from adverse consequences of HAP. Fractional exhaled nitric oxide (FeNO) is a noninvasive, underutilized tool that can serve as a surrogate for airway inflammation. We evaluated the prevalence of respiratory illness, using pulmonary questionnaires and FeNO measurements, among pregnant women in rural India who utilize biomass fuel as a source of energy within their home. Methods: We prospectively studied 60 pregnant women in their 1st and 2nd trimester residing in villages near Nagpur, Central India. We measured FeNO levels in parts per billion (ppb), St. George’s Respiratory Questionnaire (SGRQ-C) scores, and the Modified Medical Research Council (mMRC) Dyspnea Scale. We evaluated the difference in the outcome distributions between women using biomass fuels and those using liquefied petroleum gas (LPG) using two-tailed t-tests. Results: Sixty-five subjects (32 in Biomass households; 28 in LPG households; 5 unable to complete) were enrolled in the study. Age, education level, and second-hand smoke exposure were comparable between both groups. FeNO levels were higher in the Biomass vs. LPG group (25.4 ppb vs. 8.6 ppb; p-value = 0.001). There was a difference in mean composite SGRQ-C score (27.1 Biomass vs. 10.8 LPG; p-value < 0.001) including three subtotal scores for Symptoms (47.0 Biomass vs. 20.2 LPG; p-value< 0.001), Activity (36.4 Biomass vs. 16.5 LPG; p-value < 0.001) and Impact (15.9 Biomass vs. 5.2 LPG; p-value < 0.001). The mMRC Dyspnea Scale was higher in the Biomass vs. LPG group as well (2.9 vs. 0.5; p < 0.001). Conclusion: Increased FeNO levels and higher dyspnea scores in biomass-fuel-exposed subjects confirm the adverse respiratory effects of this exposure during pregnancy. More so, FeNO may be a useful, noninvasive biomarker of inflammation that can help better understand the physiologic effects of biomass smoke on pregnant women. In the future, larger studies are needed to characterize the utility of FeNO in a population exposed to HAP.

Microneedles for painless transdermal immunotherapeutic applications

Immunotherapy has recently garnered plenty of attention to improve the clinical outcomes in the treatment of various diseases. However, owing to the dynamic nature of the immune system, this approach has often been challenged by concerns regarding the lack of adequate long-term responses in patients. The development of microneedles (MNs) has resulted in the improvement and expansion of immuno-reprogramming strategies due to the housing of high accumulation of dendritic cells, macrophages, lymphocytes, and mast cells in the dermis layer of the skin. In addition, MNs possess many outstanding properties, such as the ability for the painless traverse of the stratum corneum, minimal invasiveness, facile fabrication, excellent biocompatibility, convenient administration, and bypassing the first pass metabolism that allows direct translocation of therapeutics into the systematic circulation. These advantages make MNs excellent candidates for the delivery of immunological biomolecules to the dermal antigen-presenting cells in the skin with the aim of vaccinating or treating different diseases, such as cancer and autoimmune disorders, with minimal invasiveness and side effects. This review discusses the recent advances in engineered MNs and tackles limitations relevant to traditional immunotherapy of various hard-to-treat diseases.

Peripheral Blood Eosinophilia Is Associated with Poor Outcome Post-Lung Transplantation

Eosinophils play a role in many chronic lung diseases. In lung transplantation (LTx), increased eosinophils in bronchoalveolar lavage (BAL) was associated with worse outcomes. However, the effect of peripheral blood eosinophilia after LTx has not been investigated thoroughly. A retrospective study was performed including all LTx patients between 2011-2016. Chronic lung allograft dysfunction (CLAD)-free and graft survival were compared between patients with high and low blood eosinophils using an 8% threshold ever during follow-up. A total of 102 patients (27.1%) had high blood eosinophils (≥8%) (45 before CLAD and 17 after, 40 had no CLAD) and 274 (72.9%) had low eosinophils (<8%). Patients with high blood eosinophils demonstrated worse graft survival (p = 0.0001) and CLAD-free survival (p = 0.003) compared to low eosinophils. Patients with both high blood and high BAL (≥2%) eosinophils ever during follow-up had the worst outcomes. Within the high blood eosinophil group, 23.5% had RAS compared to 3% in the group with low eosinophils (p < 0.0001). After multivariate analysis, the association between high blood eosinophils and graft and CLAD-free survival remained significant (p = 0.036, p = 0.013) independent of high BAL eosinophils and infection at peak blood eosinophilia, among others. LTx recipients with ever ≥8% blood eosinophils demonstrate inferior graft and CLAD-free survival, specifically RAS, which requires further prospective research.

Anti-alarmins in asthma: targeting the airway epithelium with next-generation biologics

Monoclonal antibody therapies have significantly improved treatment outcomes for patients with severe asthma; however, a significant disease burden remains. Available biologic treatments, including anti-immunoglobulin (Ig)E, anti-interleukin (IL)-5, anti-IL-5Rα and anti-IL-4Rα, reduce exacerbation rates in study populations by approximately 50% only. Furthermore, there are currently no effective treatments for patients with severe, type 2-low asthma. Existing biologics target immunological pathways that are downstream in the type 2 inflammatory cascade, which may explain why exacerbations are only partly abrogated. For example, type 2 airway inflammation results from several inflammatory signals in addition to IL-5. Clinically, this can be observed in how fractional exhaled nitric oxide (F_eNO), which is driven by IL-13, may remain unchanged during anti-IL-5 treatment despite reduction in eosinophils, and how eosinophils may remain unchanged during anti-IL-4Rα treatment despite reduction in F_eNO. The broad inflammatory response involving cytokines including IL-4, IL-5 and IL-13 that ultimately results in the classic features of exacerbations (eosinophilic inflammation, mucus production and bronchospasm) is initiated by release of “alarmins” thymic stromal lymphopoietin (TSLP), IL-33 and IL-25 from the airway epithelium in response to triggers. The central, upstream role of these epithelial cytokines has identified them as strong potential therapeutic targets to prevent exacerbations and improve lung function in patients with type 2-high and type 2-low asthma. This article describes the effects of alarmins and discusses the potential role of anti-alarmins in the context of existing biologics. Clinical phenotypes of patients who may benefit from these treatments are also discussed, including how biomarkers may help identify potential responders.

Blocking epithelial alarmins, upstream mediators triggered early in the asthma inflammatory response that orchestrate broad inflammatory effects, is a promising alternative approach to asthma treatment, which may be effective in a broad patient population https://bit.ly/2zqoXAw

A critical regulation of Th2 cell responses by RORα in allergic asthma

Allergic asthma is a chronic inflammatory disease of the lung and the airway, which is characterized by aberrant type 2 immune responses to otherwise unharmful aeroallergens. While the central role of Th2 cells and type 2 cytokines in the pathogenesis of allergic asthma is well documented, the regulation and plasticity of Th2 cells remain incompletely understood. By using an animal model of allergic asthma in IL-4-reporter mice, we found that Th2 cells in the lung expressed higher levels of Rora than those in the lymph nodes, and that treatment with an RORα agonist SR1078 resulted in diminished Th2 cell responses in vivo. To determine the T cell-intrinsic role of RORα in allergic asthma in vivo, we established T cell-specific RORα-deficient (Cd4creRora^f/f) mice. Upon intranasal allergen challenges, Cd4creRora^f/f mice exhibited a significantly increased Th2 cells in the lungs and the airway and showed an enhanced eosinophilic inflammation compared to littermate control mice. Studies with Foxp3^YFP-creRora^f/f mice and CD8⁺ T cell depletion showed that the increased Th2 cell responses in the Cd4creRora^f/f mice were independent of Treg cells and CD8⁺ T cells. Our findings demonstrate a critical regulatory role of RORα in Th2 cells, which suggest that RORα agonists could be effective for the treatment of allergic diseases.

Alpinetin prevents inflammatory responses in OVA-induced allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways in mice

Allergic asthma is the most common type of asthma which characterized by inflammatory responses of the airways. Alpinetin, a flavonoid compound derived from the ginger family of medicinal herbs, possesses various biological properties including anti-inflammatory, anti-oxidant and other medical effects. In this study, we aimed to evaluate the effects of alpinetin on OVA-induced allergic asthma, and further to examine its molecular mechanisms underlying these processes in vivo and in vitro. Mice were sensitized and challenged with OVA to build allergic asthma model in vivo. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells analysis and lung tissues were examined for histopathological examination. The levels of IL-5, IL-13, IL-4, IgE, TNF-α, IL-6 and IL-1β were determined by the respective ELISA kits. The PI3K/AKT/NF-κB and HO-1 signaling pathways were examined by western blot analysis. The results showed that alpinetin significantly ameliorated OVA-induced pathologic changes of lungs, such as decreasing massive inflammatory cell infiltration and mucus hypersecretion, and reduced the number of inflammatory cells in BALF. Alpinetin also decreased the OVA-induced levels of IL-4, IL-5, IL-13 and IgE. Furthermore, alpinetin inhibited OVA-induced phosphorylation of p65, IκB, PI3K and AKT, and the activity of HO-1 in vivo. More importantly, these anti-inflammatory effects and molecular mechanisms of alpinetin has also been confirmed in LPS-stimulated RAW 264.7 macrophages in vitro. In conclusion, above results indicate that alpinetin exhibites a potent anti-inflammatory activity in allergic asthma through modulating PI3K/AKT/NF-κB and HO-1 signaling pathways, which would be used as a promising therapy agent for allergic asthma.