Significant Airway Inflammation Research Articles

Eosinophilic Asthma: Pathophysiology and Therapeutic Horizons.

Asthma is a prevalent chronic non-communicable disease, affecting approximately 300 million people worldwide. It is characterized by significant airway inflammation, hyperresponsiveness, obstruction, and remodeling. Eosinophilic asthma, a subtype of asthma, involves the accumulation of eosinophils in the airways. These eosinophils release mediators and cytokines, contributing to severe airway inflammation and tissue damage. Emerging evidence suggests that targeting eosinophils could reduce airway remodeling and slow the progression of asthma. To achieve this, it is essential to understand the immunopathology of asthma, identify specific eosinophil-associated biomarkers, and categorize patients more accurately based on the clinical characteristics (phenotypes) and underlying pathobiological mechanisms (endotypes). This review delves into the role of eosinophils in exacerbating severe asthma, exploring various phenotypes and endotypes, as well as biomarkers. It also examines the current and emerging biological agents that target eosinophils in eosinophilic asthma. By focusing on these aspects, both researchers and clinicians can advance the development of targeted therapies to combat eosinophilic pathology in severe asthma.

893: EXOSOMES FROM MESENCHYMAL STEM CELLS ALLEVIATE ASPIRATION-INDUCED LUNG INJURY IN MICE

Introduction: With acidic fluid, the particulate component of the aspirate and pepsin, and bacteria from the oral cavity, gastric or oropharyngeal contents aspiration readily induces lung injury. Effective therapy remains lacking to date. The exaggerated inflammatory response has been identified as one crucial mechanism that mediates the development of lung injury in this regard. Exosomes from mesenchymal stem cells (MSCs) possess a potent anti-inflammation capacity. Based on these data, we thus conjectured that exosomes from MSCs may mitigate aspiration-induced acute lung injury. To elucidate further on this issue, we thus conducted this murine study. Methods: Adult male C57BL/6 mice were randomly allocated to the Sham group (oropharyngeal aspiration of normal saline), the AP group (oropharyngeal aspiration of mimic gastric content) or the AP-EXO group (AP plus exosomes) (n=6 in each group). The mimic gastric content consisted an acidic (pH 1.6) mixture of 12mg/mL ThickenUp®, 25μL pepsin (2mg/mL) and 20μL lipopolysaccharide (2.5mg/mL). In the AP-EXO group, mice received exosomes (1x10^8 particles/mouse, intratracheal, isolated from human placenta-derived MSCs) at 2 and 24 hours after aspiration. All mice were closely monitored for 48 hours, and each group’s lung injury level was measured. Results: Aspiration induces significant alterations in respiratory function, as our data revealed significantly higher airway resistance and lower forced expiratory volume in 0.1 seconds (FEV0.1) and dynamic compliance in mice of the AP group compared with the Sham group (all p< 0.001). Aspiration also induces significant airway inflammation, lung tissue edema and lung injury, as our data revealed significantly higher cell numbers in bronchoalveolar fluid, wet/dry weight ratio of lung tissue and lung injury score in mice of the AP group compared with the Sham group (all p< 0.001). These adverse effects of aspiration were mitigated by exosomes from MSCs, as our data demonstrated significantly lower airway resistance and, in contrast, higher FEV0.1 and dynamic compliance. Also, cell number in BALF, wet/dry weight ratio of lung tissues and lung injury score decreased in mice of the AP-EXO group compared with the AP group (all p< 0.001). Conclusions: Exosomes from MSCs mitigate aspiration-induced acute lung injury in mice.

Respiratory symptoms of COVID-19 in an adolescent patient with WHIM syndrome: a clinical case

In case of coronavirus disease 2019 (COVID-19) in children suffering from primary immunodeficiency, the last one can be an aggravating or a mitigating factor of the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome is usually classified as severe congenital neutropenia, but most patients have multiple leukocyte deficits, even panleukopenia, and therefore it can also be classified as severe combined immunodeficiency. B-lymphopenia is especially severe, and this probably partly explains the hypogammaglobulinemia. This rare disease, caused by autosomal dominant mutations, is a combined variant of immunodeficiency, which includes myelokathexis, susceptibility to infections, and hypogammaglobulinemia. Myelokathexis is a unique form of acyclic severe congenital neutropenia caused by the accumulation of mature and degenerative neutrophils in the bone marrow. Monocytopenia and lymphopenia, especially B-lymphopenia, also occur. In some patients, there are defects in the development of the cardiovascular, genitourinary and nervous systems, which in general can contribute to the extremely severe course of infectious inflammatory process, in particular due to the SARS-CoV-2. Objective: to analyze the clinical and laboratory peculiarities of coronavirus disease caused by SARS-CoV-2 in immunosuppressed patients on the example of a clinical case of COVID-19 in a child with previously diagnosed WHIM syndrome. Materials and methods. The article presents our own observation of coronavirus disease in a female adolescent suffering from previously verified primary immunodeficiency (WHIM syndrome) in the period after surgical routine correction of patent ductus arteriosus. On the 2nd day of sudden disease onset, the child was hospitalized in moderate condition with signs of airway inflammation as rhinopharyngitis and obstructive bronchitis. Results. Laboratory tests showed leukopenia, absolute neutropenia, increased levels of procalcitonin, C-reactive protein, D-dimer in serum and a reduction of activated partial thromboplastin time. The treatment included hydrobalance protection per os and by infusion, systemic and topical inhalation therapy with a short steroids course, antibacterial therapy as fourth generation cephalosporins, intravenous granulocyte colony stimulating factor, and symptomatic treatment. The girl’s condition became progressively better, she was discharged from the hospital on the 7th day to continue treatment at the outpatient settings. Conclusions. The severity of respiratory pathology and the prognosis of COVID-19 depend on the immunodeficiency type and compromised part of immune system, as well as the heterogeneity of new SARS-CoV-2 strains. The aggravating/protective role of primary immunodeficiency, in particular WHIM syndrome, in determining COVID-19 severity is currently limited because of small number of observations and requires further data collection. The presented clinical case describes the classic moderate coronavirus disease as airway infection in an adolescent suffering from primary immunodeficiency.

Measuring Short-Term Exposures to H2O2 Among Exposed Workers; A Feasibility Study.

Hydrogen peroxide (H2O2) is a strong oxidizing agent often used in hair coloring and as a component in disinfecting and bleaching processes. Exposures to H2O2 generate reactive oxygen species (ROS) that can cause significant airway irritation and inflammation. Even though workers have reported symptoms associated with sensitivity and irritation from acute exposures below the H2O2 occupational exposure levels (OELs), a lack of sensitive analytical methods for measuring airborne concentrations currently prevents evaluating low or peak H2O2 exposures. To fill these gaps, we propose two different sensitive approaches: (i) luminol chemiluminescence (CL) to specifically measure H2O2; and (ii) photonic sensor method based on the ferrous-xylenol orange assay to evaluate total oxidative potential (OP), a measure of ROS in sampled air. We chose two exposure scenarios: hairdressers preparing and applying hair color to clients (both in simulated and field environments) and workers operating disinfecting cycles at a bottling company. Hair coloring took about 1 h for each client, and the application of the coloring product generated the highest H2O2 concentrations. OP values were highly correlated with H2O2 concentrations (CL measurement) and allowed peak measurements as low as 6 µg m-3 of H2O2 concentrations. The bottling company used a disinfectant containing H2O2, acetic acid and peracetic acid (PAA) in an enclosed process. The photonic sensor was immediately saturated. The CL results showed that the process operator had the highest exposures during a 15-min cycle. There is still a need to develop these direct reading methods for operating in the field, but we believe that in the future an OEL for OP could protect workers from developing airway irritation and inflammation by reducing exposures to oxidizing chemicals.

Allergic airway inflammation induces upregulation of the expression of IL-23R by macrophages and not in CD3 + T cells and CD11c+F4/80− dendritic cells of the lung

Interleukin 23 and the interleukin 23 receptor (IL-23-IL23R) are described as the major enhancing factors for Interleukin 17 (IL-17) in allergic airway inflammation. IL-17 is considered to induce neutrophilic inflammation in the lung, which is often observed in severe, steroid-resistant asthma-phenotypes. For that reason, understanding of IL-23 and IL-17 axis is very important for future therapy strategies, targeting neutrophil pathway of bronchial asthma.This study aimed to investigate the distribution and expression of IL-23R under physiological and inflammatory conditions. Therefore, a house dust mite (HDM) model of allergic airway inflammation was performed by treating mice with HDM intranasally. Immunofluorescence staining with panel of antibodies was performed in lung tissues to examine the macrophage, dendritic cell, and T cell subpopulations. The allergic airway inflammation was quantified by histopathological analysis, ELISA measurements, and airway function.HDM-treated mice exhibited a significant allergic airway inflammation including higher amounts of NE+ cells in lung parenchyma. We found only a small amount of IL-23R positives, out of total CD3+T cells, and no upregulation in HDM-treated animals. In contrast, the populations of F4/80+ macrophages and CD11c+F4/80− dendritic cells (DCs) with IL-23R expression were found to be higher. But HDM treatment leads to a significant increase of IL-23R+ macrophages, only. IL-23R was expressed by every examined macrophage subpopulation, whereas only Mϕ1 and hybrids between Mϕ1 and Mϕ2 phenotype and not Mϕ2 were found to upregulate IL-23R. Co-localization of IL-23R and IL-17 was only observed in F4/80+ macrophages, suggesting F4/80+ macrophages express IL-23R along with IL-17 in lung tissue.The study revealed that macrophages involving the IL-23 and IL-17 pathway may provide a potential interesting therapeutic target in neutrophilic bronchial asthma.

Therapeutic Inhibition of Cathepsin S Reduces Inflammation and Mucus Plugging in Adult βENaC-Tg Mice.

Background Elevated levels of the cysteine protease cathepsin S (CatS) are associated with chronic mucoobstructive lung diseases such as cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). We have previously demonstrated that prophylactic treatment with a CatS inhibitor from birth reduces inflammation, mucus plugging, and lung tissue damage in juvenile β-epithelial Na+ channel-overexpressing transgenic (βENaC-Tg) mice with chronic inflammatory mucoobstructive lung disease. In this study, we build upon this work to examine the effects of therapeutic intervention with a CatS inhibitor in adult βENaC-Tg mice with established disease. Methods βENaC-Tg mice and wild-type (WT) littermates were treated with a CatS inhibitor from 4 to 6 weeks of age, and CatS−/−βENaC-Tg mice were analysed at 6 weeks of age. Bronchoalveolar lavage (BAL) fluid inflammatory cell counts were quantified, and lung tissue destruction and mucus obstruction were analysed histologically. Results At 6 weeks of age, βENaC-Tg mice developed significant airway inflammation, lung tissue damage, and mucus plugging when compared to WT mice. CatS−/−βENaC-Tg mice and βENaC-Tg mice receiving inhibitor had significantly reduced airway mononuclear and polymorphonuclear (PMN) cell counts as well as mucus plugging. However, in contrast to CatS−/−βENaC-Tg mice, therapeutic inhibition of CatS in βENaC-Tg mice had no effect on established emphysema-like lung tissue damage. Conclusions These results suggest that while early CatS targeting may be required to prevent the onset and progression of lung tissue damage, therapeutic CatS targeting effectively inhibited airway inflammation and mucus obstruction. These results indicate the important role CatS may play in the pathogenesis and progression of mucoobstructive lung disease.

S2243 Reversal Obstructive Lung Disease in Ulcerative Colitis: A Rare Extraintestinal Manifestation

INTRODUCTION: Ulcerative colitis (UC) is associated with several extraintestinal manifestations that may affect various organ systems, lungs involvement are relatively rare. Our case highlights a patient presenting with symptoms of reversible obstructive airway disease associated with UC disease activity. CASE DESCRIPTION/METHODS: A 23 YO male with history of Ulcerative pancolitis presented to Virginia Commonwealth University (VCU)-IBD Center with unresolving cough, wheezing, diarrhea, fecal urgency and abdominal pain. Physical exam was notable for moderate abdominal tenderness and minimal lung wheeze. Lab data reveled elevated CRP of 14 mg/dL and fecal calprotectin of 1285 µg/gm. CT abdomen/pelvis revealed active inflammation with diffuse colonic wall thickening. UC Treated initially with Mesalamine after diagnosis at age of 22 YO, combination therapy with Adalimumab and Methotrexate started few weeks prior to presentation.Pulmonary symptoms were manifested in cough and wheezing. These symptoms were exacerbated with worsening UC activity and more responsive to steroids courses. CT chest was negative for interstitial lung disease. Prior pulmonary function test (PFT) showed mild obstructive airway disease requiring albuterol and corticosteroids inhalers. He was found to have infectious colitis causing UC flare. GI and pulmonary symptoms improved with therapy optimization, steroids and methotrexate were stopped. Clinical remission were maintained with Adalimumab monotherapy. He remained off respiratory inhalers. Subsequent PFT with improved lung volumes and function. DISCUSSION: The prevalence and pathogenesis of lung involvement in IBD is poorly understood but it may be related to the underlying inflammatory process. Respiratory manifestations of ulcerative colitis are rare, they can be broadly categorized into airway disease and interstitial lung disease. These manifestations usually follow the IBD disease activity and often exacerbate during relapses. Patients with airway disease can have significant airway inflammation, which could potentially lead to airway narrowing. The most common presenting symptoms include cough and wheezing. Chest radiographs are often non-specific and pulmonary function testing may reveal obstruction pattern. CT scan of the chest may not show remarkable findings.This case report highlights that it is imperative to maintain a high index of suspicion for the development of pulmonary disease in the setting of IBD in order to institute appropriate treatment early and avoid complications.

Soluble CD93 in allergic asthma

CD93 has been shown critical roles in inflammatory and immune diseases. However, in allergic asthma, the potential roles of soluble CD93 (sCD93) have not been well studied. We conducted house dust mite (HDM) stimulation with Der p 1 in BEAS-2B and U937 cells, followed by treatment with dexamethasone or small interfering RNA against CD93. A HDM-induced murine allergic asthma model was also established. We estimated the power of sCD93 to predict allergic asthma in a retrospective post-hoc analysis containing 96 human samples. HDM-stimulated BEAS-2B cells showed increased mRNA expression levels of IL-6, IL-8, IL-33, TSLP, and CD93. The CD93 level in culture supernatants steadily increased for 24 h after allergen stimulation, which was significantly suppressed by both dexamethasone and CD93 silencing. CD93 silencing increased IL-6 and TSLP, but not IL-33 levels in culture supernatants. HDM-induced asthma mice showed significant airway hyperresponsiveness and inflammation with Th2 cytokine activation, along with decreased CD93 expression in bronchial epithelial cells and lung homogenates but increased serum CD93 levels. The sCD93 level in asthma patients was significantly higher than that in healthy controls and could predict asthma diagnosis with moderate sensitivity (71.4%) and specificity (82.4%) (AUC = 0.787, P < 0.001). The level of sCD93 which has potential role to predict asthma significantly increased after HDM stimulation via IL-6 and TSLP in vitro and in vivo.

Impact of Community Respiratory Viral Infections in Urban Children With Asthma

To prospectively evaluate the influence of viral infection on respiratory symptoms, lung function, and nasal cytokines in children with asthma living in an urban environment.The study included 53 children with asthma living in Detroit, Michigan.Subjects were recruited with a screening questionnaire distributed through a community-based research partnership. Subjects participated in 4 2-week surveillance assessments, corresponding with fall, winter, spring, and summer seasons over the course of 1 year. During each 2-week surveillance period, spirometry, fraction of exhaled nitric oxide, symptom reports, and nasal lavage samples were obtained on 3 separate occasions. Respiratory symptoms were measured by using a previously published respiratory symptom score. “Sick periods” were defined when symptom scores were >2, and an additional assessment with previously stated measurements was completed over the 1-week sick period. Subjects were contacted weekly via telephone to monitor for illnesses and initiate sick period assessments. Nasal lavage samples were analyzed for the following: presence of respiratory viral nucleic acid, rhinovirus typing and viral copy numbers, and messenger RNA and protein expression analysis of select biomarkers previously shown to be elevated in rhinovirus infection.The investigators enrolled 53 subjects, who were predominantly African American, elementary school–aged, and had high prevalence of home smoke exposure. Approximately 75% of subjects had mild intermittent or mild persistent asthma. Six hundred fifty-eight nasal aspirates were obtained. Of the samples, 22.9% of surveillance samples and 33.7% of respiratory illness samples were virus positive, with rhinovirus accounting for 48.9% of infections. Comparing the presence of respiratory virus with high- and low-symptom illnesses, children with severe colds (symptom scores >5) had signs of airway inflammation on spirometry with a statistically significant decrease of ∼10% of predicted forced expiratory flow at 25% to 75% of pulmonary volume as well as higher biomarker elevations in both nasal messenger RNA of CXCL-10 and protein expression of CXCL8, CXCL10, CCL-2, and CCL-4 when compared with virus-negative asymptomatic conditions. Mild virus-positive colds (symptoms scores 1–4) and asymptomatic infections showed normal airway function by spirometry and fewer biomarker elevations. Viral-negative coldlike illnesses had increased nitric oxide with otherwise normal spirometry.Urban children with asthma have reduced forced expiratory flow at 25% to 75% of pulmonary volume and higher elevations of nasal biomarkers during high-symptom respiratory infections compared with low-symptom infections or symptomatic virus-negative illnesses.Researchers in this study prospectively evaluate the effect of viral infections on respiratory symptoms and lung function in urban children with asthma. High-symptom colds were associated with decreases in small airway function compared with lower-symptom illnesses. Interestingly, the nasal biomarkers elevated during symptomatic viral infections were related to neutrophil recruitment and not eosinophil or allergic response. Also, many upper respiratory tract illnesses in the study were virus negative, suggesting other triggers for symptoms.

CANNABIS-ASSOCIATED SECONDARY SPONTANEOUS PNEUMOTHORAX

SESSION TITLE: Tuesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/22/2019 01:00 PM - 02:00 PM INTRODUCTION: Cannabis is the second most commonly smoked substance in US after tobacco. Marijuana smokers, especially young individuals, tend to develop similar symptoms as tobacco smokers. We present a patient with spontaneous secondary pneumothorax due to apical bullous disease possibly due to daily heavy marijuana usage. CASE PRESENTATION: A 30-year-old man with pmh of traumatic left-sided pneumothorax presented to the ED with one week history of progressive pleuritic chest pain and shortness of breath. He denied any history of trauma. Patient reported history of heavy daily marijuana smoking (more than five blunts a day for six years). He denied tobacco use. Physical examination revealed hyperresonance on percussion along with decreased right lung sounds. Bedside US of chest showed absence of lung sliding. Chest x-ray demonstrated large right-sided pneumothorax. Patient underwent left chest tube placement. Repeat CXR showed resolution of pneumothorax. CT scan of the chest was performed and showed multiple bilateral apical sub-pleural bullae, most prominent at the right apex and along the left upper lobe medially. Patient did not have family history of pneumothorax and no benign skin lesions, arachnodactyly, or joint hyper-mobility. Laboratory analysis showed negative HIV test and normal rheumatoid factor, homo-cysteine, and alpha-1 antitrypsin levels. Patient underwent right-sided VATS, right upper lobe wedge resection and mechanical pleurodesis. The patient was clinically and radio-logically stable following the removal of his chest tube and discharged home with the appropriate follow-up appointments DISCUSSION: The exact mechanism of cannabis-induced bullous lung disease and secondary spontaneous pneumothorax is not well known. The proposed mechanism involves common marijuana smoking techniques: breath holding, Valsalva and Muller’s maneuvers. Prolonged Valsalva maneuver during breath holding following deep inhalation of the smoke pressurizes the air in the lungs and could result in barotrauma to the lungs with rupture of sub pleural blebs. Furthermore, marijuana smoking is associated with significant airway inflammation, mucus hypersecretion and ciliated epithelial cell reduction, changes similar to those seen in tobacco smokers [5]. Diagnosis of cannabis-induced secondary pneumothorax is established by a process of exclusion of other apical bullous lung diseases. This patient was a habitual marijuana smoker who consistently performed breath holding and Valsalva maneuvers; he had no other risk factors for development of bullous disease or pneumothorax. The combination of prolonged breath holding and the toxic components in marijuana led to the barotrauma and pneumothorax. CONCLUSIONS: Penumothorax in young population can be secondary to different etiologies. Our case underlines the importance of maintaining a high index of suspicion for Cannabis as a cause of bullous lung disorder. Reference #1: Wu TC, Tashkin DP, Djahed B, Rose JE. Pulmonary hazards of smoking marijuana as compared with tobacco. N. Engl. J. Med. 1988; 318: 347–51. Reference #2: Tashkin DP, Gliederer F, Rose J et al. Effects of varying marijuana smoking profile on deposition of tar and absorption of CO and δ-9-THC. Pharmacol. Biochem. Behav. 40, 651–656 (1991). Reference #3: Roth MD, Arora A, Barsky SH, Kleerup EC, Simmons M, Tashkin DP. Airway inflammation in young marijuana and tobacco smokers. Am J Respir Crit Care Med 1998;157:928–937. DISCLOSURES: No relevant relationships by Obed Adarkwah, source=Web Response No relevant relationships by dina ahmed, source=Web Response no disclosure on file for Farhad Arjomand; No relevant relationships by Laila Cordero, source=Web Response No relevant relationships by Louis Gerolemou, source=Web Response No relevant relationships by Nabil Mesiha, source=Web Response No relevant relationships by Ankur Mogla, source=Web Response No relevant relationships by jad sargi, source=Web Response

Airway inflammation and injury in children with prevalent weakly acidic gastroesophageal refluxes.

In children with gastroesophageal reflux (GER) both acid refluxes (AR) and weakly acidic refluxes (WAR) can induce respiratory symptoms (RS). To characterize the airway inflammation in children with more prevalent WAR or AR (defined according a ROC curve analysis), we performed a 3 year-retrospective review of the medical records of patients who underwent fiberoptic bronchoscopy for difficult-to-treat chronic/recurrent respiratory symptoms and who had a positive multiple intraluminal esophageal impedance (pH/MII) monitoring. In the 13 WAR and 11 AR children, the number of cells recovered by bronchoalveolar lavage (BAL) was similar [0.78 (0.29-1.28) x 106 cells, and 1.05 (0.68-1.64) x 106 cells, respectively] (P = 0.22). A neutrophilic alveolitis and an elevated lipid-laden-macrophage (LLM) index were detected in both groups: no differences were found in neutrophils and lymphocyte percentages or in LLM index between WAR and AR children. In contrast, higher BAL epithelial cell proportions were seen in WAR [10.4 (4.85-23.45) %], as compared to AR [2.5 (1.25-7.25) %] children (P = 0.0045), suggesting greater airway damage in the formers. In the whole patient population a significant correlation was found between the proportions of BAL epithelial cells and the number of WAR events (r = 0.43; P = 0.037). Finally, elevated BAL concentrations of substance P and of pepsin were observed, not statistically different in the WAR and AR groups. In this patient population, WAR events can be associated with a significant airway inflammation and injury that, because of the biochemical mechanisms involved, are likely not completely preventable and/or counteracted by anti-acid treatments.

Knockout of RAGE ameliorates mainstream cigarette smoke-induced airway inflammation in mice

BackgroundThe receptor for advanced glycation end products (RAGE), a multiligand receptor, has been proved to be implicated in inflammatory responses in chronic obstructive pulmonary disease (COPD). In this study, we investigated the role of RAGE in cigarette smoke (CS)-induced airway inflammation in COPD. MethodsWild-type (WT) and RAGE gene knockout (KO) mice were exposed to mainstream CS or room air for 2h twice daily, 6days per week for consecutive 4weeks. Cell counts and proinflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF). Lung tissues were collected for histological examination and gene expression profiling by cDNA microarray. ResultsCS exposure induced significant airway inflammation in WT mice evidenced by histological inflammatory changes in HE stain with increased neutrophils and proinflammatory cytokines in the BALF, which were all attenuated by RAGE KO. cDNA microarray indicated a total of 179 upregulated genes and 351 downregulated genes in mouse lungs. Among these genes, S100 proteins (S100A8 and S100A9), the RAGE common ligands, were significantly downregulated, which were validated by real-time qPCR. Further analyses by Gene Ontology, KEGG and Disease Ontology suggested these differentiated expressed genes significantly related to the immune-inflammatory responses in lungs via crosstalking with a complicated network of signaling pathways. ConclusionsKnockout of RAGE significantly ameliorates mainstream CS-induced airway inflammation in mice possibly via downregulating S100A8/A9 expression and its related immune-inflammatory responses.

Effects of an early intervention using human amniotic epithelial cells in a COPD rat model

The study aimed to investigate the effect of an early intervention using human amniotic epithelial cell (hAEC) in a rat model of chronic obstructive pulmonary disease (COPD). Twenty-four specific pathogen-free Wistar rats were randomized to the control, COPD, and COPD+hAEC groups. COPD was established by intratracheal LPS injection combined with smoke fumigation over 30days. On the first day of model establishment rats in the AEC group also received intratracheal instillation of 500,000 hAECs isolated from the placenta of healthy donors. The mean linear intercept (MLI) and mean alveolar number (MAN) were used to assess the degree of lung emphysema. IL-8 was measured using a radioimmunoassay, surfactant protein D (SP-D) was measured by ELISA, and matrix metalloproteinase (MMP)2 and MMP8 expression was assessed by PCR. Smoke fumigation combined to LPS injection successfully established a COPD rat model with significant emphysema and airway inflammation, elevated MLI and MAN, elevated systemic and lung tissue levels of IL-8 and SP-D (P<0.05), and high expression of MMP2 and MMP8. Rats in the COPD+hAEC group exhibited alleviated lung damage, MLI and MAN (P<0.05), reduced systemic and lung tissue levels of IL-8 and SP-D (P<0.05) and MMP2 and MMP8 expression (P<0.05). Early intervention using hAECs could delay disease progression in rats with COPD.

Tracheobronchoscopic Assessment of Exercise-Induced Pulmonary Hemorrhage and Airway Inflammation in Barrel Racing Horses.

BackgroundPoor performance is often suspected to be associated with EIPH in barrel racing horses; however, there are no published reports of EIPH for this discipline. The prevalence of EIPH in barrel racing horses is also unknown.ObjectivesThis study was performed to determine the prevalence of EIPH and signs of airway inflammation in barrel racing horses under normal racing conditions in Alberta.AnimalsAbout 170 barrel racing horses.MethodsObservational cross‐sectional study. Tracheobronchoscopic examinations were performed at least 30 minutes postrace. Video recordings were scored off‐site independently by two observers for EIPH and tracheal mucus accumulation (TMA). Horses with an EIPH score ≥2 were not assessed for TMA. Interobserver agreement was calculated by weighted κ statistics. Run times, environmental variables, and clinical information were also recorded for analysis.Results77/170 (45.3%) of horses examined showed evidence of EIPH (grade ≥ 1). Interobserver agreement was 0.94. 140/141 (99.3%) of horses assessed for TMA showed evidence of tracheal mucus accumulation (grade ≥ 1) with 104/141 (73.8%) having a TMA score ≥ 2. Interobserver agreement was 0.73. A weak positive association was found between EIPH scores and average run speed, the presence of cough at rest reported by the riders, increased recovery time, exercise intolerance, and outdoor pattern.Conclusions and clinical importanceThe high prevalence of EIPH observed in the sampled population indicates that barrel racing induces substantial stress on the lungs. The presence of EIPH did not impact negatively on performance. Factors such as environmental dust and frequent traveling might have contributed to the high prevalence of TMA observed.

Association between virus detection/quantification and clinical signs of airway inflammation in horses at training

Previous studies investigating the potential involvement of viruses in airway inflammation were based either on serological tests or on PCR from nasal swabs only. The objectives of this study were to determine the incidence of welland less-characterised viruses in the equine airways, and their association with clinical signs. In a 2-year prospective longitudinal study, nasal swabs (NS) and tracheal washes (TW) were collected monthly on 52 Standardbred racehorses at training (581 samples). Equine aand g-herpesviruses, equine rhinitis virus-A and -B, equine adenovirus-A, and equine influenza virus were investigated by qPCR. Any positive sample was subcategorised as non-quantifiable (>LOD and LOQ). Clinical signs (nasal discharge, coughing), and tracheal mucus score were simultaneously recorded. In TW, respective monthly incidences were 27.9% (EHV-5), 24.8% (EHV-2), 7.1% (ERBV), 3.8% (EHV-4), 1.9% (EAdV1) and 0.2% (EHV-1, ERAV). EIV has not been detected in any sample. Molecular detection of EHV-2 and ERBV in TW were significantly associated with coughing (OR 3.1; 95% CI 1.4-7.1; P1⁄40.01 and OR 5.3; 95% CI 2.1-14.0; P<0.001, respectively). Positive samples for EHV-2 in TW were significantly associated with tracheal mucus score 2 (OR 2.1; 95% CI 1.2-3.8; P1⁄40.02). When based on quantifiable detection, ERBV only was significantly associated with coughing (OR 15.0; 95% CI 3.7-60.0; P<0.001). Positive samples for any virus in NS were not associated with clinical signs. Based on our data, detecting ERBV in TW is a major risk-factor of coughing. This virus should be considered when investigating horses with inflammatory airway disease.

Exercise test using dry air in random adolescents: Temporal profile and predictors of bronchoconstriction.

Guidelines recommend exercise tests using dry air to diagnose exercise-induced bronchoconstriction (EIB). Lung function changes subsequent to these tests have not been investigated in a general adolescent population, and it remains unknown whether signs of airway inflammation, measured using exhaled nitric oxide (FeNO), can predict a positive response. The aim of this study was to investigate the temporal aspect of decline in forced expiratory volume in 1 s (FEV1 ) after an exercise test using dry air, and to investigate predictors of EIB. From a cross-sectional study on adolescents aged 13-15 years (n = 3838), a random subsample of 146 adolescents (99 with and 47 without self-reported exercise-induced dyspnoea) underwent standardized treadmill exercise tests for EIB while breathing dry air. Of the adolescents, 34% had a positive EIB test (decline of ≥10% in FEV1 from baseline) within 30 min. Of the subjects with EIB, 53% showed the greatest decline in FEV1 at 5 to 10 min (mean decline 18.5%), and the remaining 47% of the subjects showed the greatest decline at 15 to 30 min (mean decline 18.9%) after exercise. Increased FeNO (>20 ppb), female gender and self-reported exercise-induced dyspnoea were independently associated with a positive EIB test. When assessing general adolescents for EIB with exercise test using dry air, there is a temporal variation in the greatest FEV1 decline after exercise. Therefore, lung function should be measured for at least 30 min after the exercise. Increased FeNO, female gender and self-reported exercise-induced dyspnoea can be predictors of a positive EIB test.

Acute exposure to silica nanoparticles aggravate airway inflammation: different effects according to surface characteristics.

Silica nanoparticles (SNPs) are widely used in many scientific and industrial fields despite the lack of proper evaluation of their potential toxicity. This study examined the effects of acute exposure to SNPs, either alone or in conjunction with ovalbumin (OVA), by studying the respiratory systems in exposed mouse models. Three types of SNPs were used: spherical SNPs (S-SNPs), mesoporous SNPs (M-SNPs), and PEGylated SNPs (P-SNPs). In the acute SNP exposure model performed, 6-week-old BALB/c female mice were intranasally inoculated with SNPs for 3 consecutive days. In the OVA/SNPs asthma model, the mice were sensitized two times via the peritoneal route with OVA. Additionally, the mice endured OVA with or without SNP challenges intranasally. Acute SNP exposure induced significant airway inflammation and airway hyper-responsiveness, particularly in the S-SNP group. In OVA/SNPs asthma models, OVA with SNP-treated group showed significant airway inflammation, more than those treated with only OVA and without SNPs. In these models, the P-SNP group induced lower levels of inflammation on airways than both the S-SNP or M-SNP groups. Interleukin (IL)-5, IL-13, IL-1β and interferon-γ levels correlated with airway inflammation in the tested models, without statistical significance. In the mouse models studied, increased airway inflammation was associated with acute SNPs exposure, whether exposed solely to SNPs or SNPs in conjunction with OVA. P-SNPs appear to be relatively safer for clinical use than S-SNPs and M-SNPs, as determined by lower observed toxicity and airway system inflammation.

Interactions of Francisella tularensis with Alveolar Type II Epithelial Cells and the Murine Respiratory Epithelium.

Francisella tularensis is classified as a Tier 1 select agent by the CDC due to its low infectious dose and the possibility that the organism can be used as a bioweapon. The low dose of infection suggests that Francisella is unusually efficient at evading host defenses. Although ~50 cfu are necessary to cause human respiratory infection, the early interactions of virulent Francisella with the lung environment are not well understood. To provide additional insights into these interactions during early Francisella infection of mice, we performed TEM analysis on mouse lungs infected with F. tularensis strains Schu S4, LVS and the O-antigen mutant Schu S4 waaY::TrgTn. For all three strains, the majority of the bacteria that we could detect were observed within alveolar type II epithelial cells at 16 hours post infection. Although there were no detectable differences in the amount of bacteria within an infected cell between the three strains, there was a significant increase in the amount of cellular debris observed in the air spaces of the lungs in the Schu S4 waaY::TrgTn mutant compared to either the Schu S4 or LVS strain. We also studied the interactions of Francisella strains with human AT-II cells in vitro by characterizing the ability of these three strains to invade and replicate within these cells. Gentamicin assay and confocal microscopy both confirmed that F. tularensis Schu S4 replicated robustly within these cells while F. tularensis LVS displayed significantly lower levels of growth over 24 hours, although the strain was able to enter these cells at about the same level as Schu S4 (1 organism per cell), as determined by confocal imaging. The Schu S4 waaY::TrgTn mutant that we have previously described as attenuated for growth in macrophages and mouse virulence displayed interesting properties as well. This mutant induced significant airway inflammation (cell debris) and had an attenuated growth phenotype in the human AT-II cells. These data extend our understanding of early Francisella infection by demonstrating that Francisella enter significant numbers of AT-II cells within the lung and that the capsule and LPS of wild type Schu S4 helps prevent murine lung damage during infection. Furthermore, our data identified that human AT-II cells allow growth of Schu S4, but these same cells supported poor growth of the attenuated LVS strain in vitro. Collectively, these data further our understanding of the role of AT-II cells in Francisella infections.

Smooth Muscle Calcium Signaling and Contraction in the Small Airways of the House Dust Mite Asthma Mouse Model

The small intrapulmonary airways are the major contributors to reversible airflow limitation in asthma. However, the mechanisms responsible for the increased small‐airway responsiveness to bronchoconstrictors (airway hyperresponsiveness) that characterized asthma pathophysiology are not fully understood. We used precision‐cut lung slices and microscope imaging approaches to investigate the contraction and intracellular calcium signaling in the smooth muscle of small airways from mice chronically challenged with house dust mite extract (HDM) during 3 to 7 weeks. Mice challenged with HDM developed a significant airway inflammation characterized by the presence of eosinophils, lymphocytes, neutrophils, and monocytes that spread through the airway tree and reached the small airways. Superfusion of lung slices with methacholine (MCh) induced a concentration‐dependent airway contraction that was significantly increased in the small airways of the HDM‐challenge mice than in PBS‐challenged mice (controls). MCh stimulation induced intracellular Ca2+ oscillations in the smooth muscle cells on the small airways. The frequency of these Ca2+ oscillations increased with MCh concentration and was higher in airway smooth muscle cells from the HDM‐exposed mice than from controls. The results suggest that airway hyperresponsiveness in asthma is caused by an increased contractility of the airway smooth muscle cells in the small airways which is accompanied by an increased intracellular Ca2+ response to bronchoconstrictors

MMP-12-mediated by SARM-TRIF signaling pathway contributes to IFN-γ-independent airway inflammation and AHR post RSV infection in nude mice.

BackgroundRespiratory syncytial virus (RSV) is one of the most frequently observed pathogens during infancy and childhood. However, the corresponding pathogenesis has not been determined to date. We previously demonstrated that IFN-γ plays an important role in RSV pathogenesis, and SARM-TRIF-signaling pathway could regulate the production of IFN-γ. This study is to investigate whether T cells or innate immune cells are the predominant producers of IFN-γ, and further to explore other culprits in addition to IFN-γ in the condition of RSV infection.MethodsNormal BALB/c mice and nude mice deficient in T cells were infected intranasally with RSV. Leukocytes in bronchoalveolar lavage fluid were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. IFN-γ and MMP-12 were detected by ELISA. MMP408, a selective MMP-12 inhibitor, was given intragastrically. Resveratrol, IFN-γ neutralizing antibody and recombinant murine IFN-γ were administered intraperitoneally. SARM and TRIF protein were semi-quantified by Western blot. siRNA was used to knock-down SARM expression.ResultsRSV induced significant airway inflammation and AHR in both mice; IFN-γ was significantly increased in BALB/c mice but not in nude mice. MMP-12 was dramatically increased in both mice but earlier in nude mice. When MMP-12 was inhibited by MMP408, RSV-induced respiratory symptoms were alleviated. SARM was significantly suppressed while TRIF was significantly enhanced in both mice strains. Following resveratrol administration in nude mice, 1) SARM inhibition was prevented, 2) TRIF and MMP-12 were correspondingly down-regulated and 3) airway disorders were subsequently alleviated. Moreover, when SARM was efficiently knocked down using siRNA, TRIF and MMP-12 were markedly enhanced, and the anti-RSV effects of resveratrol were remarkably abrogated. MMP-12 was significantly increased in the IFN-γ neutralizing antibody-treated BALB/c mice but reduced in the recombinant murine IFN-γ-treated nude mice.ConclusionsMMP-12 can result in at least part of the airway inflammation and AHR independent of IFN-γ. And SARM-TRIF- signaling pathway is involved in regulating the overproduction of MMP-12. To the best of our knowledge, this study is the first that has examined the effects of SARM on MMP-12 and further highlights the potential to target SARM-TRIF-MMP-12 cascades to treat RSV infection.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-015-0176-8) contains supplementary material, which is available to authorized users.