Pulmonary Thromboembolism Presenting as Asthma

When a patient presents with wheezing, pulmonary embolism is not usually considered as a possible cause. However, undoubtedly bronchoconstriction can be caused by pulmonary emboli and occasionally wheezing may be so obvious as to suggest a diagnosis of bronchial asthma. Eleven cases are reported in which wheezing was attributable to recurrent pulmonary emboli and one in which it was a clamant feature after a single embolic incident.     

Role of IL-6 in Asthma and Other Inflammatory Pulmonary Diseases

The incidence and severity of chronic lung diseases is growing and affects between 100 and 150 million people worldwide and is associated with a significant rate of mortality. Unfortunately, the initial cause that triggers most chronic lung diseases remains unknown and current available therapies only ameliorate, but do not cure the disease. Thus, there is a need for identification of new targets and development of novel therapies especially for those most severely affected. IL-6, like other inflammatory cytokines, has been shown to be elevated in different lung diseases, but it was considered a byproduct of ongoing inflammation in the lung. However, recent studies support a dissociation of IL-6 from inflammation in the lung and suggest that this cytokine plays an active role in pathogenesis of asthma and, in all likelihood, COPD. IL-6 may therefore be a germane target for treatment of these and other chronic lung disease. Here, we provide an overview of the studies in mouse models and human patients that provide support for the involvement of IL-6 in lung diseases.     

Vitronectin Expression in the Airways of Subjects with Asthma and Chronic Obstructive Pulmonary Disease

Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration, wound healing, and tissue remodeling. The primary cellular source of vitronectin is hepatocytes; it is not known whether resident cells of airways produce vitronectin, even though the glycoprotein has been found in exhaled breath condensate and bronchoalveolar lavage from healthy subjects and patients with interstitial lung disease. It is also not known whether vitronectin expression is altered in subjects with asthma and COPD. In this study, bronchial tissue from 7 asthmatic, 10 COPD and 14 control subjects was obtained at autopsy and analyzed by immunohistochemistry to determine the percent area of submucosal glands occupied by vitronectin. In a separate set of experiments, quantitative colocalization analysis was performed on tracheobronchial tissue sections obtained from donor lungs (6 asthmatics, 4 COPD and 7 controls). Vitronectin RNA and protein expressions in bronchial surface epithelium were examined in 12 subjects who undertook diagnostic bronchoscopy. Vitronectin was found in the tracheobronchial epithelium from asthmatic, COPD, and control subjects, although its expression was significantly lower in the asthmatic group. Colocalization analysis of 3D confocal images indicates that vitronectin is expressed in the glandular serous epithelial cells and in respiratory surface epithelial cells other than goblet cells. Expression of the 65-kDa vitronectin isoform was lower in bronchial surface epithelium from the diseased subjects. The cause for the decreased vitronectin expression in asthma is not clear, however, the reduced concentration of vitronectin in the epithelial/submucosal layer of airways may be linked to airway remodeling.     

Pulmonary Inflammation and Airway Hyperresponsiveness in a Mouse Model of Asthma Complicated by Acid Aspiration

Several studies have indicated a strong association between asthma and aspiration of stomach contents. However, the complex association between these inflammatory processes has not been studied extensively in animal models. In the present study, we developed an animal model to evaluate the inflammatory cell, chemokine, and airway responses to asthma complicated by aspiration. The model was produced by sensitizing mice to cockroach allergens from house-dust extracts. Mice with asthma-like airway responses then were inoculated intratracheally with either an acidic solution or saline. Acid aspiration increased airway hyperresponsiveness in mice with asthma for at least 8 h. After 6 h, the combined injury caused an additive, not synergistic, increase in airway hyperresponsiveness and neutrophil recruitment to the airways. Although cysteinyl leukotrienes in bronchoalveolar lavage fluid were higher after acid aspiration, treatment with a receptor antagonist before aspiration did not diminish airway hyperresponsiveness. Vagal mechanisms reportedly mediate airway responses in acid aspiration; however, pretreatment with an anticholinergic agent did not reduce airway responses to acid. These results are consistent with an effective model of the acute effects of aspiration on the allergic lung. Further studies could examine how various forms of aspiration influence the severity of asthma.Abbreviations: BAL, bronchoalveolar lavage; MIP, macrophage inflammatory protein; Penh, enhanced pauseAsthma is an escalating public health problem in children and adults.⁴⁹ In patients with asthma, exaggerated immune responses to allergens produce lung inflammation and dysfunction. These responses lead to the characteristic airway hyperresponsiveness, obstructed airflow, and clinical symptoms associated with asthma.⁴⁹ Although several conditions aggravate asthma, much recent attention has focused on the provocative association between asthma and aspiration of stomach acid. The prevalence of gastroesophageal reflux in some asthma patient populations is greater than 50% ²¹ and significantly exceeds the prevalence in nonasthmatic populations.^20,47 This finding suggests an association between the 2 diseases and the possibility that gastroesophageal reflux promotes or aggravates symptoms that lead to the diagnosis asthma. In fact, several studies have shown a decrease in asthma symptoms after medical or surgical treatment of gastroesophageal reflux.^4,11,18,19Stomach acid may exacerbate asthma symptoms through 2 mechanisms. The first is a vagal reflex initiated in response to acid in the esophagus. Clinical studies in humans^20,50 and experimental studies in animals^34,48 have shown that acid in the esophagus promotes neurologic responses leading to bronchoconstriction and impaired airway function. Esophageal acid also may cause substance P- mediated neurogenic inflammation.¹⁶ The second mechanism is due to aspiration into the airways, which also has been documented to occur in asthma patients.²⁵ The presence of acid in the trachea increases airway hyperresponsiveness in anesthetized animals through vagal mechanisms,⁴⁸ particularly in the presence of preexisting lung inflammation.³² In addition to neurologic responses, aspiration of acid induces a pattern of pulmonary inflammation characterized by the release of proinflammatory cytokines and neutrophil recruitment.^26,31 That inflammation may also increase airway responsiveness.⁶Well-established models for both asthma^6,10,14,27 and aspiration^31,39 studies are available currently. However, the patterns of inflammation that occur after sequential insults are complex and may not be predicted by studies of the responses to individual insults.⁸ In addition, the mechanisms for exacerbation of airway hyperresponsiveness by aspiration in asthma have been limited to use of anesthetized animals. A model that allows recovery from the anesthesia after delivery of the aspirate permits the development and evaluation of pulmonary changes under more physiologic conditions. Therefore, the goals of this study were to: (1) describe acute exacerbation of asthma by acid aspiration in mice after recovery from anesthesia; (2) determine the effects of combined insults on airway hyperresponsiveness; and (3) profile the cellular and cytokine responses to the combined insults to assess potential mechanisms for the pulmonary responses to asthma complicated by aspiration.     

Microbial Communities in the Upper Respiratory Tract of Patients with Asthma and Chronic Obstructive Pulmonary Disease

Respiratory infections are well-known triggers of chronic respiratory diseases. Recently, culture-independent tools have indicated that lower airway microbiota may contribute to pathophysiologic processes associated with asthma and chronic obstructive pulmonary disease (COPD). However, the relationship between upper airway microbiota and chronic respiratory diseases remains unclear. This study was undertaken to define differences of microbiota in the oropharynx of asthma and COPD patients relative to those in healthy individuals. To account for the qualitative and quantitative diversity of the 16S rRNA gene in the oropharynx, the microbiomes of 18 asthma patients, 17 COPD patients, and 12 normal individuals were assessed using a high-throughput next-generation sequencing analysis. In the 259,572 total sequence reads, α and β diversity measurements and a generalized linear model revealed that the oropharynx microbiota are diverse, but no significant differences were observed between asthma and COPD patients. Pseudomonas spp. of Proteobacteria and Lactobacillus spp. of Firmicutes were highly abundant in asthma and COPD. By contrast, Streptococcus, Veillonella, Prevotella, and Neisseria of Bacteroidetes dominated in the healthy oropharynx. These findings are consistent with previous studies conducted in the lower airways and suggest that oropharyngeal airway microbiota are important for understanding the relationships between the various parts of the respiratory tract with regard to bacterial colonization and comprehensive assessment of asthma and COPD.     

诱导痰黏蛋白5AC对支气管哮喘和慢性阻塞性肺疾病的鉴别价值

摘要 目的：对支气管哮喘（BA）患者和慢性阻塞性肺疾病（COPD）患者诱导痰黏蛋白5AC（MUC5AC）、炎症细胞和炎症因子水平进行比较以及相关性分析,评估MUC5AC鉴别BA和COPD的价值。方法：选取2018年9月至2019年9月来海南医学院第一附属医院就诊的BA稳定期患者（BA组）60例,同期COPD稳定期（COPD组）患者60例。诱导痰法采样并处理痰液,检测诱导痰MUC5AC、炎症细胞中性粒细胞（Neu）、巨噬细胞（Mac）、嗜酸性粒细胞（Eos）、淋巴细胞（Lym）、炎症因子血管内皮生长因子（VEGF）、细胞间黏附分子-1（ICAM-1）、白介素13（IL-13）和白介素17（IL-17）水平,通过Pearson相关分析对MUC5AC水平与Neu、Mac、Eos、Lym、VEGF、ICAM-1、IL-13、IL-17的关系进行分析。此外,采用受试者工作特征(ROC)曲线分析MUC5AC、炎症细胞及炎症因子鉴别诊断BA及COPD的效能。结果：COPD组诱导痰MUC5AC水平高于BA组,差异有统计学意义（P＜0.05）;COPD组诱导痰Mac和Eos水平均低于BA组,COPD组诱导痰Neu水平高于BA组,差异均有统计学意义（P＜0.05）;COPD组诱导痰VEGF、ICAM-1、IL-13和IL-17水平均低于BA组,差异均有统计学意义（P＜0.05）;Pearson相关分析结果显示,诱导痰MUC5AC与炎症细胞Mac、Eos和炎症因子VEGF、ICAM-1、IL-13和IL-17呈负相关（P＜0.05）,与炎症细胞Neu呈正相关（P＜0.05）。经ROC曲线分析可得：诱导痰MUC5AC鉴别BA和COPD的曲线下面积、灵敏度、特异度以及约登指数均高于炎症细胞Neu、Mac、Eos以及炎症因子VEGF、ICAM-1、IL-13、IL-17。结论：COPD患者诱导痰MUC5AC水平高于BA患者,MUC5AC与炎症细胞和炎症因子有关,MUC5AC的检测有助于鉴别BA或COPD,其有望作为临床BA或COPD的监测指标和治疗靶点。     

Childhood Asthma Management Pre- and Post-Incident Asthma Hospitalization

Many hospitalizations for asthma could potentially be avoided with appropriate management. The aim of this study was to analyze data on disease management of a paediatric population with a hospitalization for asthma. The study population comprised 6–17 year old subjects belonging to three local health units of the Lombardy Region, northern Italy. Regional administrative databases were used to collect data on: the number of children with an incident hospitalization for asthma during the 2004–2006 period, anti-asthma therapy, specialist visit referrals, and claims for spirometry, released in the 12 months before and after hospitalization. Each patient’s asthma management profile was compared with GINA guideline recommendations. Among the 183 hospitalized subjects, 101 (55%) received therapy before hospitalization and 82 (45%) did not. 10% did not receive any therapy either before or after hospital admission and in 13% the therapy was discontinued afterward. Based on GINA guidelines, asthma management adhered to recommendations only for 55% of subjects. Results may suggest that for half of hospitalized subjects, inaccurate diagnosis, under-treatment/scarce compliance with asthma guidelines by physicians, and/or scarce compliance to therapy by patients/their parents occurred. In all these cases, hospitalization would be a proxy indicator of preventable poor control of disease, rather than a proxy indicator of severity.     

支气管哮喘患儿肺功能状态及Th1Th2指标的变化观察

目的:观察支气管哮喘患儿肺功能状态及Th1Th2指标的变化情况。方法:选取2013年10月~2015年8月本院诊治的65例支气管哮喘患儿为观察组,另选择同期接受体检的健康同龄儿童65名为对照组。比较两组患儿肺功能状态及Th1Th2指标,观察不同严重程度及分期支气管哮喘患儿的肺功能状态及Th1Th2指标。结果:观察组患儿肺功能指标及血清Th1Th2指标均低于对照组,差异具有统计学意义(P0.05);观察组患儿发作期肺功能指标及血清Th1Th2指标明显低于缓解期,差异具有统计学意义(P0.05);重度患儿肺功能指标及血清Th1Th2指标均低于轻度及中度患儿,差异具有统计学意义(P0.05);中度患儿肺功能指标及血清Th1Th2指标低于轻度患儿,差异具有统计学意义(P0.05)。结论:支气管哮喘患儿肺功能状态及Th1Th2指标的变化较大,且疾病分期与疾病严重程度对其检测结果也有较大影响。