Leukotriene E4–induced pulmonary inflammation is mediated by the P2Y12 receptor

Of the potent lipid inflammatory mediators comprising the cysteinyl leukotrienes (LTs; LTC4, LTD4, and LTE4), only LTE4 is stable and abundant in vivo. Although LTE4 shows negligible activity at the type 1 and 2 receptors for cys-LTs (CysLT1R and CysLT2R), it is a powerful inducer of mucosal eosinophilia and airway hyperresponsiveness in humans with asthma. We show that the adenosine diphosphate (ADP)–reactive purinergic (P2Y12) receptor is required for LTE4-mediated pulmonary inflammation. P2Y12 receptor expression permits LTE4 -induced activation of extracellular signal-regulated kinase in Chinese hamster ovary cells and permits chemokine and prostaglandin D2 production by LAD2 cells, a human mast cell line. P2Y12 receptor expression by LAD2 cells is required for competition between radiolabeled ADP and unlabeled LTE4 but not for direct binding of LTE4, suggesting that P2Y12 complexes with another receptor to recognize LTE4. Administration of LTE4 to the airways of sensitized mice potentiates eosinophilia, goblet cell metaplasia, and expression of interleukin-13 in response to low-dose aerosolized allergen. These responses persist in mice lacking both CysLT1R and CysLT2R but not in mice lacking P2Y12 receptors. The effects of LTE4 on P2Y12 in the airway were abrogated by platelet depletion. Thus, the P2Y12 receptor is required for proinflammatory actions of the stable abundant mediator LTE4 and is a novel potential therapeutic target for asthma

Effect of Procaterol, a β2 Selective Adrenergic Receptor Agonist, on Airway Inflammation and Hyperresponsiveness

Background: β-agonists are frequently used as bronchodilators for asthma as not only a reliever but also a controller, and their utility has increased with the development of long-acting β2 selective drugs. Although antiinflammatory effects of β2 selective-agonists have been reported in vitro, side effects on augmentation of airway hyperresponsiveness by chronic use of β2 selective-agonists have been described in several reports. In this study, we investigated the effects of procaterol, a second-generation β2-agonist, on airway inflammation in vivo using an antigen-specific murine model of asthma. Methods: Mice immunized with ovalbumin (OVA) + alum and challenged with inhaled ovalbumin were orally administered procaterol during the challenge. After inhalation, the mice were tracheostomized and placed in a body box under controlled ventilation to measure airway resistance before and after acetylcholine inhalation. Results: Administration of procaterol at a clinical dose equivalent did not augment airway hyperresponsiveness, inflammation of the airway wall, or subsequent airway wall thickening induced by OVA inhalation. BALF cell analysis revealed that the eosinophil number in the BALF was significantly reduced in procaterol-treated mice compared to untreated mice. Conclusions: Oral administration of procaterol at a clinical dose did not augment airway responsiveness, but did reduce eosinophil inflammation

Patency Capsule Aspiration

A 77-year-old man with anemia who had undergone 2 abdominal surgeries for colon and gastric cancer experienced dyspnea after swallowing a patency capsule before endoscopy for investigating the cause of anemia. Chest radiography and computed tomography revealed that the patency capsule was located within the bronchus intermedius. It was successfully removed by flexible bronchoscopy. The balloon was placed over the capsule and inflated. Subsequently, the catheter was pulled, while thus dragging the capsule with it and preventing its destruction. In cases of patency capsule aspiration, the capsule must be removed without deformity, before it causes inflammation by releasing barium into the airway

Patency Capsule Aspiration

A 77-year-old man with anemia who had undergone 2 abdominal surgeries for colon and gastric cancer experienced dyspnea after swallowing a patency capsule before endoscopy for investigating the cause of anemia. Chest radiography and computed tomography revealed that the patency capsule was located within the bronchus intermedius. It was successfully removed by flexible bronchoscopy. The balloon was placed over the capsule and inflated. Subsequently, the catheter was pulled, while thus dragging the capsule with it and preventing its destruction. In cases of patency capsule aspiration, the capsule must be removed without deformity, before it causes inflammation by releasing barium into the airway

Serum MMP3 and IL1-RA levels may be useful biomarkers for detecting asthma and chronic obstructive pulmonary disease overlap in patients with asthma

Background: Asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO) is characterized by concurrent features of asthma and COPD. Since disease pathogenesis, severities, and treatments differ between asthma and ACO, it is important to differentiate them. Objective: To clarify and compare the characteristics of ACO and asthma and identify the serum biomarkers for differentiating them, especially in older patients. Methods: This study used the data of 639 participants from the nationwide cohort study, the NHOM-Asthma study, an asthma registry in Japan, with complete information on smoking history, respiratory function, and serum biomarkers. ACO was defined as the self-reported comorbidity of COPD or emphysema, or with obstructive pulmonary function and smoking history (pack-years≥10). The clinical characteristics of patients with ACO and asthma without COPD were compared. The serum biomarkers for differentiation were examined using receiver operating characteristic curves and multivariable analysis. The associations between the biomarkers and age were also analyzed. Results: Of the 639 asthma patients, 125 (19.6%) were diagnosed with ACO; these patients were older and male-dominant and had a higher prevalence of comorbidities such as hypertension, diabetes, and stroke. Among the serum biomarkers that were significantly different between ACO and asthma without COPD, the YKL-40/CHI3L1, MMP3, and IL-1RA levels showed a high area under the curve for discriminating ACO. Only the MMP3 and IL-1RA levels were significantly higher among ACO patients, regardless of age and sex; the YKL-40/CHI3L1 levels were not different due to the effect of age. Conclusion: MMP3 and IL-1RA may be useful serum biomarkers for distinguishing ACO from asthma