Meiyo Tamaoka

The epidermal growth factor receptor mediates allergic airway remodelling in the rat

The chronicity of bronchial asthma is attributed to persistent airway inflammation and to a variety of structural changes, or remodelling, that includes smooth muscle and goblet cell hyperplasia. To investigate the mechanisms of airway remodelling, the current authors used an established allergen (ovalbumin; OVA)-driven rodent model (the Brown Norway rat). Brown Norway rats were sensitised to OVA and challenged three times at 5-day intervals to evoke airway remodelling. The effects of an epidermal growth factor (EGF) receptor inhibitor, AG1478, and a cysteinyl leukotriene-1 receptor antagonist, montelukast, on epithelial and airway smooth muscle (ASM) cell proliferation in vivo in response to repeated OVA challenge were tested. Three challenges with leukotriene (LT)D4 were given, to examine their effects on remodelling with and without AG1478 pretreatment. OVA challenges caused ASM hyperplasia, with an increase in mass, epithelial cell proliferation and goblet cell proliferation. AG1478 prevented the changes, as did montelukast. Multiple OVA challenges increased heparin-binding EGF-like growth factor but not EGF expression by airway epithelium. LTD4 reproduced the changes in remodelling induced by OVA and this was blocked by AG1478. Allergen-induced airway epithelial and airway smooth muscle remodelling is mediated by cysteinyl leukotrienes via the cysteinyl leukotriene-1 receptor with downstream effects on the epidermal growth factor receptor axis.

Sites of allergic airway smooth muscle remodeling and hyperresponsiveness are not associated in the rat

The cause-and-effect relationship between airway smooth muscle (ASM) remodeling and airway hyperresponsiveness (AHR) following allergen challenge is not well established. Using a rat model of allergen-induced ASM remodeling we explored the relationship between the site of ASM remodeling and AHR. Brown Norway rats, sensitized and challenged (3 times at 5-day intervals) with ovalbumin, were intranasally administered 0.1 mg/kg budesonide 24 and 1 h before challenge. Airway responses to aerosolized methacholine were assessed 48 h or 1 wk after three challenges. Airways were stained and analyzed for total airway wall area, area of smooth muscle-specific α-actin, and goblet cell hyperplasia, and the constant-phase model was used to resolve the changes in respiratory system mechanics into large airway and peripheral lung responses. After three ovalbumin challenges, there was a significant increase in ASM area and in the total wall area in all sized airways as well as an increase in goblet cells in the central airways. Budesonide inhibited ASM growth and central airway goblet cell hyperplasia following ovalbumin challenges. Budesonide also inhibited small but not large airway total wall area. AHR was attributable to excessive responses of the small airways, whereas responsiveness of the large airways was unchanged. Budesonide did not inhibit AHR after repeated challenge. We conclude that ASM remodeling induced by repeated allergen challenges involves the entire bronchial tree, whereas AHR reflects alterations in the lung periphery. Prevention of ASM remodeling by corticosteroid does not abrogate AHR.

Proteome Analysis of Bronchoalveolar Lavage Fluid in Chronic Hypersensitivity Pneumonitis

BACKGROUND Hypersensitivity pneumonitis (HP) is an immune-mediated lung disease induced by inhalation of numerous antigens. Pathologically, chronic HP tends to show usual interstitial pneumonia (UIP) and fibrotic nonspecific interstitial pneumonia (fNSIP) patterns. Patients with UIP pattern present insidious onset and a risk for acute exacerbations. METHODS To evaluate the proteomic differences of bronchoalveolar lavage fluid (BALF) between UIP and fNSIP patterns, BALF from seven patients with UIP pattern and four patients with fNSIP pattern was examined using two-dimensional gel electrophoresis and mass spectrometry. RESULTS By individually comparing each BALF sample, we found that the protein levels of surfactant protein A (SP-A), immunoglobulin heavy chain α, α-2 heat shock glycoprotein, haptoglobin β, and immunoglobulin J chain were significantly higher in the patients with UIP pattern than those in the patients with fNSIP pattern. In contrast, the protein levels of glutathione s-transferase, vitamin D-binding protein, and β-actin were significantly higher in the patients with fNSIP pattern than those in the patients with UIP pattern. To confirm the results of SP-A in the BALF proteome, we performed enzyme-linked immunosorbent assay in a larger group. The concentrations of SP-A in BALF from the patients with UIP pattern were significantly higher than those from the patients with fNSIP pattern (2.331 ± 1.656 μg/ml vs. 1.319 ± 1.916 μg/ml, p = 0.034). CONCLUSIONS We identified several proteins that may play roles in the development of pathological differences between UIP and fNSIP patterns of chronic HP.

Churg-strauss syndrome versus chronic eosinophilic pneumonia on high-resolution computed tomographic findings.

Objectives: The aim of this study was to compare the high-resolution computed tomographic findings between Churg-Strauss syndrome (CSS) and chronic eosinophilic pneumonia (CEP). Methods: We retrospectively reviewed the clinical records of 16 patients with CSS and 34 patients with CEP. Results: Twelve (35%) of the 34 patients with CEP had a history of asthma. Although the subpleural distribution of ground-glass opacities (GGOs) and consolidation was common both in CSS and CEP, the midzone distribution was more frequent in CSS (44%) than in CEP (12%). Centrilobular nodules within GGOs were significantly more frequent in CSS (56%) than in CEP (18%). In contrast, traction bronchiectasis associated with volume loss was demonstrated more frequently in CEP (74%) than in CSS (25%). Conclusions: On high-resolution computed tomography, the presence of the midzone distribution and nodules within GGOs without traction bronchiectasis suggests CSS rather than CEP.

Identification of fungal DNA in BALF from patients with home-related hypersensitivity pneumonitis

BACKGROUND In Japan, a major type of home-related hypersensitivity pneumonitis (HP) is summer-type HP, which is caused by Trichosporon asahii (T. asahii) or Trichosporon mucoides. Some patients with home-related HP test negative for antibodies against Trichosporon; yet, a causative mold antigen cannot be identified. METHODS We analyzed 19 patients with home-related HP, 8 healthy volunteers, and 35 patients with other diseases. We extracted DNA from cell pellets of bronchoalveolar lavage fluid (BALF), amplified the DNA by PCR using Trichosporon-specific primers or other fungus-specific primers, and cloned as well as sequenced the PCR amplicon. Other primers used were specific for Acremonium chrysogenum, Aspergillus fumigatus, Aspergillus niger, Fusarium napiforme, Humicola fuscoatra, Penicillium corylophilum, and Pezizia domiciliana. RESULTS We detected Trichosporon DNA (n = 17) and F. napiforme DNA (n = 2) by PCR in 19 patients with home-related HP; however, these species were not identified in healthy volunteers. After sequencing of the PCR amplicon for Trichosporon species, we identified T. asahii (n = 11), Trichosporon japonicum (n = 1), and Cryptococcus uzbekistanesis (n = 4). CONCLUSION We could detect fungal DNA in BALF cell pellets from patients with home-related HP. These data suggest that this method might be useful to detect antigens responsible for home-related HP.

Synthetic double-stranded RNA enhances airway inflammation and remodelling in a rat model of asthma

Respiratory viral infections are frequently associated with exacerbations of asthma. Double‐stranded RNA (dsRNA) produced during viral infections may be one of the stimuli for exacerbation. We aimed to assess the potential effect of dsRNA on certain aspects of chronic asthma through the administration of polyinosine‐polycytidylic acid (poly I:C), synthetic dsRNA, to a rat model of asthma. Brown Norway rats were sensitized to ovalbumin and challenged three times to evoke airway remodelling. The effect of poly I:C on the ovalbumin‐induced airway inflammation and structural changes was assessed from bronchoalveolar lavage fluid and histological findings. The expression of cytokines and chemokines was evaluated by real‐time quantitative reverse transcription PCR and ELISA. Ovalbumin‐challenged animals showed an increased number of total cells and eosinophils in bronchoalveolar lavage fluid compared with PBS‐challenged controls. Ovalbumin‐challenged animals treated with poly I:C showed an increased number of total cells and neutrophils in bronchoalveolar lavage fluid compared with those without poly I:C treatment. Ovalbumin‐challenged animals showed goblet cell hyperplasia, increased airway smooth muscle mass, and proliferation of both airway epithelial cells and airway smooth muscle cells. Treatment with poly I:C enhanced these structural changes. Among the cytokines and chemokines examined, the expression of interleukins 12 and 17 and of transforming growth factor‐β1 in ovalbumin‐challenged animals treated with poly I:C was significantly increased compared with those of the other groups. Double‐stranded RNA enhanced airway inflammation and remodelling in a rat model of bronchial asthma. These observations suggest that viral infections may promote airway remodelling.

A Familial History of Pulmonary Fibrosis in Patients with Chronic Hypersensitivity Pneumonitis

Background: Hypersensitivity pneumonitis (HP) is an immunologically mediated lung disease induced by the inhalation of a variety of antigens. Patients with chronic HP often have a family history of pulmonary fibrosis. This strongly suggests that both genetic and environmental factors play an important role in the pathogenesis of chronic HP. Objectives: We aimed to investigate the epidemiology and clinical features of chronic HP patients with a family history of pulmonary fibrosis. Methods: We retrospectively reviewed the clinical information of 114 cases diagnosed with chronic HP with insidious onset between 1992 and 2009. Results: Twenty cases (17.5%) were identified as having a family history of pulmonary fibrosis. All of these patients had lived apart from their afflicted relatives for at least several decades. The familial cases were younger than the nonfamilial cases at onset (57.5 ± 9.6 vs. 64.0 ± 7.0 years old, p = 0.008). The predicted vital capacity percentage and partial pressure of oxygen in arterial blood gas were significantly higher in the familial cases. There were no differences between the 2 groups in gender, smoking history, bronchoalveolar lavage fluid profile, radiologic findings or other clinical features. Conclusions: We found a familial clustering in patients with chronic HP. Various factors including genetic susceptibility to pulmonary fibrosis and environmental factors may contribute to the development of familial chronic HP.

Depletion of CD8+ T cells enhances airway remodelling in a rodent model of asthma

Airway remodelling is induced by persistent airway inflammation and may lead to severe asthma. T cells play a pivotal role in asthmatic airway inflammation but their role in remodelling is poorly understood. Although previous studies have revealed that CD8+ T cells inhibit the late airway response and airway inflammation in a rat model of asthma, their effects on airway remodelling have not been evaluated. The aim of this study was to examine the role of CD8+ T cells in airway remodelling. Brown Norway rats were sensitized with ovalbumin (OVA) on day 0. CD8+ T cells in rats were depleted during the repeated challenges by treating them with a CD8α monoclonal antibody (OX‐8). Control rats were treated with mouse ascites. Sensitized rats were challenged with OVA on days 14, 19 and 24 or were sham challenged with phosphate‐buffered saline. On day 29, bronchoalveolar lavage and lung tissues were harvested. Repeated OVA inhalations evoked significant increases in the numbers of periodic acid–Schiff‐positive epithelial cells and proliferating cell nuclear antigen‐positive epithelial cells, and in airway smooth muscle mass compared to the control group. CD8‐depleted rats had significant enhancement of these changes, principally affecting the large airways. These results suggest that endogenous CD8+ T cells have inhibitory effects on airway remodelling in this model of asthma.

Serodiagnosis of Mycobacterium avium Complex Pulmonary Disease in Rheumatoid Arthritis

Background:Mycobacterium avium complex (MAC) pulmonary disease (PD) is often difficult and complicated to diagnose or to discriminate from follicular bronchitis, bronchiectasis, or other conditions associated with rheumatoid arthritis (RA) lung in the clinical setting. Objective: We investigated whether a serologic test for anti-glycopeptidolipid (GPL) antibody was useful for distinguishing MAC-PD from RA lung in diagnosis. Methods: Serum IgA antibody to MAC-specific GPL core antigen was measured by an enzyme immunoassay. Antibody levels were measured in sera from 14 RA patients with MAC-PD (RA + MAC), 20 RA patients with bronchial or bronchiolar lesions without MAC-PD (RA w/o MAC), 20 RA patients without pulmonary lesions (RA only), and 25 healthy volunteers (HV). Results: The levels of serum anti-GPL antibodies were higher in the RA + MAC group than in the RA w/o MAC, RA-only, and HV groups (2.87 ± 2.83 vs. 0.50 ± 0.45, 0.31 ± 0.24, and 0.38 ± 0.10 U/ml, respectively; p < 0.001). With the cutoff point in receiver-operating characteristic analysis set at 0.7 U/ml, the serologic test differentiated RA + MAC from RA w/o MAC with a sensitivity of 100% and specificity of 90%. Conclusions: This serologic test for anti-GPL antibody is useful for diagnosing MAC-PD in RA.

Pulmonary Artery Leiomyosarcoma Diagnosed without Delay.

A 63-year-old female presented with abnormal lung shadows but had, apart from this, few symptoms. Computed tomography (CT) revealed multiple nodules and blockage of the pulmonary artery. She was immediately diagnosed with pulmonary artery sarcoma based on a careful differential diagnosis and underwent surgery. Her tumor was pathologically diagnosed as leiomyosarcoma (i.e. intimal sarcoma). Pulmonary artery sarcoma can be easily confounded with thromboembolism in a clinical setting and some cases are diagnosed post mortem only. In our case, clinical prediction scores (Wells score, Geneva score, and revised Geneva score) for the pulmonary embolism showed low probability. Moreover, chest CT showed uncommon findings for pulmonary thromboembolism, as the nodules were too big for thrombi. Because surgical resection can provide the only hope of long-term survival in cases of pulmonary artery sarcoma, clinicians should consider this possibility in the differential diagnosis of pulmonary embolism. Clinical prediction scores and CT findings might help to reach the correct diagnosis of pulmonary artery sarcoma.