Hiromichi Aso

Pulmonary Hypertension as a Prognostic Indicator at the Initial Evaluation in Idiopathic Pulmonary Fibrosis

Background: The impact of pulmonary hypertension (PH) on survival has been demonstrated in severe cases with idiopathic pulmonary fibrosis (IPF) who were referred for transplantation. However, whether PH is a predictor of survival remains unclear in milder cases. Objectives: To evaluate the survival impact of pulmonary artery pressure measured during the initial evaluation in patients with IPF. Methods: We retrospectively analyzed the initial evaluation data of 101 consecutive IPF patients undergoing right heart catheterization. Patients evaluated with supplemental oxygen were excluded. Predictors of 5-year survival were analyzed using the Cox proportional model. Results: The mean forced vital capacity (FVC) % predicted, diffusing capacity of the lung for carbon monoxide (DLCO) % predicted, and mean pulmonary artery pressure (MPAP) were 70.2 ± 20.1%, 47.9 ± 19.5%, and 19.2 ± 6.5 mm Hg, respectively. A univariate Cox proportional hazard model showed that the body mass index, %FVC, %DLCO, baseline PaO2, modified Medical Research Council score, 6-min walk distance, and lowest SpO2 of the 6-min walk test were significantly predictive of survival. The MPAP and pulmonary vascular resistance of right heart catheterization were also significant. With stepwise, multivariate Cox proportional analysis, MPAP (HR = 1.064; 95% CI 1.015-1.116, p = 0.010) and %FVC (HR = 0.965, 95% CI 0.949-0.982, p < 0.001) were independent determinants of survival. Analysis of the receiver operating curve revealed MPAP >20 mm Hg to be optimal for predicting the prognosis. Conclusions: Higher MPAP and lower %FVC at the initial evaluation were significant independent prognostic factors of IPF. The current results suggested the importance of the initial evaluation of PH for patients with IPF.

STIM1 Regulates Platelet-Derived Growth Factor-Induced Migration and Ca2+ Influx in Human Airway Smooth Muscle Cells

It is suggested that migration of airway smooth muscle (ASM) cells plays an important role in the pathogenesis of airway remodeling in asthma. Increases in intracellular Ca2+ concentrations ([Ca2+]i) regulate most ASM cell functions related to asthma, such as contraction and proliferation. Recently, STIM1 was identified as a sarcoplasmic reticulum (SR) Ca2+ sensor that activates Orai1, the Ca2+ channel responsible for store-operated Ca2+ entry (SOCE). We investigated the role of STIM1 in [Ca2+]i and cell migration induced by platelet-derived growth factor (PDGF)-BB in human ASM cells. Cell migration was assessed by a chemotaxis chamber assay. Human ASM cells express STIM1, STIM2, and Orai1 mRNAs. SOCE activated by thapsigargin, an inhibitor of SR Ca2+-ATPase, was significantly blocked by STIM1 siRNA and Orai1 siRNA but not by STIM2 siRNA. PDGF-BB induced a transient increase in [Ca2+]i followed by sustained [Ca2+]i elevation. Sustained increases in [Ca2+]i due to PDGF-BB were significantly inhibited by a Ca2+ chelating agent EGTA or by siRNA for STIM1 or Orai1. The numbers of migrating cells were significantly increased by PDGF-BB treatment for 6 h. Knockdown of STIM1 and Orai1 by siRNA transfection inhibited PDGF-induced cell migration. Similarly, EGTA significantly inhibited PDGF-induced cell migration. In contrast, transfection with siRNA for STIM2 did not inhibit the sustained elevation of [Ca2+]i or cell migration induced by PDGF-BB. These results demonstrate that STIM1 and Orai1 are essential for PDGF-induced cell migration and Ca2+ influx in human ASM cells. STIM1 could be an important molecule responsible for airway remodeling.

Differential Regulation of Airway Smooth Muscle Cell Migration by E-Prostanoid Receptor Subtypes

Migration of airway smooth muscle (ASM) cells plays an important role in the pathophysiology of airway hyperresponsiveness and remodeling in asthma. It has been reported that prostaglandin (PG)E2 inhibits migration of ASM cells. Although PGE2 regulates cellular functions via binding to distinct prostanoid EP receptors, the role of EP receptor subtypes in mechanisms underlying cell migration has not been fully elucidated. We investigated the role of EP receptors in the inhibitory effects of PGE2 on the migration of human ASM cells. Migration induced by platelet-derived growth factor (PDGF)-BB (10 ng/ml, 6 h) was assessed by a chemotaxis chamber assay. PDGF-BB-induced cell migration was inhibited by PGE2, the specific EP2 agonist ONO-AE1-259-01, the specific EP4 agonist ONO-AE1-329, and cAMP-mobilizing agents. The inhibition of cell migration by PGE2 was significantly reversed by a blockade of EP2 and EP4 receptors using antagonists or transfection with siRNAs. Moreover, PGE2, the EP2 agonist, and the EP4 agonist significantly increased phosphorylation of small heat shock protein 20, one of the protein substrates for protein kinase A (PKA), with depolymerization of actin. In contrast, the EP3 agonist ONO-AE-248 significantly promoted baseline cell migration without affecting PDGF-BB-induced cell migration. In summary, activation of EP2 and EP4 receptors and subsequent activation of the cAMP/PKA pathway are the main mechanisms of inhibition of ASM cell migration by PGE2. HSP20 phosphorylation by PKA is possibly involved in this mechanism. Conversely, EP3 is potent in promoting cell migration. EP receptor subtypes may be novel therapeutic target molecules in airway remodeling and asthma.

Effects of specific prostanoid EP receptor agonists on cell proliferation and intracellular Ca2+ concentrations in human airway smooth muscle cells

Increased airway smooth muscle mass due to cell proliferation contributes to airway hyper-responsiveness and remodeling in patients with asthma. Prostaglandin E2 (PGE2) inhibits proliferation of airway smooth muscle cells, but the role of prostanoid EP receptor subtypes in mechanisms involved has not been fully elucidated yet. We investigated the effects of specific prostanoid EP receptor agonists on cell proliferation and intracellular Ca(2+) concentrations ([Ca(2+)]i) in human airway smooth muscle cells. Cell numbers were assessed by mitochondria-dependent reduction of 4-[3-(4-lodophenyl)-2-(4-nitrophenyl)-2H-5-tetrazolio]-1, 3-benzene disulfonate to formazan (WST-1 assay). RT-PCR data showed that human airway smooth muscle cells express EP2, EP3, and EP4 but not EP1 receptor mRNA. PGE2 (1nM-1μM) inhibited cell proliferation induced by 5% fetal bovine serum (FBS) in a concentration-dependent manner. (16S)-9-deoxy-9β-chloro-15-deoxy-16-hydroxy-17, 17-trimethylene-19, 20-didehydro PGE2 sodium salt (ONO-AE1-259-01; EP2 receptor agonist) and 16-(3-methoxymethyl)phenyl-ω-tetranor-3,7-dithia PGE2 (ONO-AE1-329; EP4 receptor agonist) inhibited the 5% FBS-induced cell proliferation. ONO-AE1-259-01 and ONO-AE1-329 also significantly increased the cytosolic cAMP levels. In contrast, 11,15-O-dimethyl PGE2 (ONO-AE-248; EP3 receptor agonist) elicited an oscillatory increase in [Ca(2+)]i but did not affect the cell growth or cAMP levels. [(17S)-2,5-ethano-6-oxo-17,20-dimethyl PGE1] (ONO-DI-004; EP1 receptor agonist) did not affect cell growth, cAMP levels, or [Ca(2+)]i. In conclusion, PGE2 inhibits FBS-induced cell proliferation mostly via EP2 and EP4 receptor activation and subsequent cAMP elevation. The EP3 receptor agonist causes an increase in [Ca(2+)]i without affecting cell growth. There is no functional expression of the EP1 receptor. Research on prostanoid EP receptors may lead to novel therapeutic strategies for treatment of asthma.

Ca2+ influx and ATP release mediated by mechanical stretch in human lung fibroblasts.

One cause of progressive pulmonary fibrosis is dysregulated wound healing after lung inflammation or damage in patients with idiopathic pulmonary fibrosis and severe acute respiratory distress syndrome. The mechanical forces are considered to regulate pulmonary fibrosis via activation of lung fibroblasts. In this study, the effects of mechanical stretch on the intracellular Ca(2+) concentration ([Ca(2+)]i) and ATP release were investigated in primary human lung fibroblasts. Uniaxial stretch (10-30% in strain) was applied to fibroblasts cultured in a silicone chamber coated with type I collagen using a stretching apparatus. Following stretching and subsequent unloading, [Ca(2+)]i transiently increased in a strain-dependent manner. Hypotonic stress, which causes plasma membrane stretching, also transiently increased the [Ca(2+)]i. The stretch-induced [Ca(2+)]i elevation was attenuated in Ca(2+)-free solution. In contrast, the increase of [Ca(2+)]i by a 20% stretch was not inhibited by the inhibitor of stretch-activated channels GsMTx-4, Gd(3+), ruthenium red, or cytochalasin D. Cyclic stretching induced significant ATP releases from fibroblasts. However, the stretch-induced [Ca(2+)]i elevation was not inhibited by ATP diphosphohydrolase apyrase or a purinergic receptor antagonist suramin. Taken together, mechanical stretch induces Ca(2+) influx independently of conventional stretch-sensitive ion channels, the actin cytoskeleton, and released ATP.

Endobronchial ultrasound transbronchial needle aspiration in older people

The usefulness and safety of endobronchial ultrasound transbronchial needle aspiration (EBUS‐TBNA) have been established recently, but no study has evaluated whether or not aging increases the risk of the procedure. In the present study, we aimed to assess the usefulness and safety of EBUS‐TBNA in older patients.

Factors Affecting the Diagnostic Yield of Transbronchial Biopsy Using Endobronchial Ultrasonography with a Guide Sheath in Peripheral Lung Cancer.

Objective Endobronchial ultrasonography with a guide sheath (EBUS-GS) and virtual bronchoscopic navigation (VBN) improves the diagnostic yield in patients with peripheral pulmonary lesions (PPLs). Most previous reports on EBUS-GS-guided transbronchial biopsy (TBB) have included patients with benign and malignant diseases. We aimed to determine the factors that predicted a successful diagnosis by EBUS-GS-guided TBB diagnostic in patients with small peripheral lung cancer, with a focus on the high-resolution computed tomography (HRCT) findings before bronchoscopy. Methods We retrospectively reviewed the medical records of 173 consecutive patients with 175 small (≤30 mm) PPLs who were diagnosed with primary lung cancer between June 2010 and October 2013 at Nagoya University Hospital. All patients underwent EBUS-GS-guided TBB with VBN using a ZioStation computer workstation (Ziosoft, Osaka, Japan). We analyzed the patient characteristics, HRCT findings, diagnostic yield, and the diagnostic factors in small peripheral lung carcinoma. Results The EBUS probe position was within the PPL in 83 of the 175 lesions (47%) and 112 (64.0%) cases were successfully diagnosed by EBUS-GS-guided TBB. A univariate analysis revealed that the following factors were associated with a significantly higher diagnostic yield: CT bronchus sign positivity, a lesion of >20 mm in diameter, a solid nodule, and a probe position that was within the lesion. The following factors were not significant: the lesion location, the number of biopsies, and the lung cancer histology. A multivariate analysis revealed that the following factors significantly affected the diagnostic yield: CT bronchus sign positivity [odds ratio (OR) =2.479]; a probe position that was within the lesion (OR=2.542); and a solid nodule (OR=2.304). Conclusion The significant factors that were significantly associated with a successful diagnosis using EBUS-GS-guided TBB in small peripheral lung carcinoma were as follows: CT bronchus sign positivity, a solid nodule, and a probe position that was within the lesion.

Antineutrophil Cytoplasmic Antibody-associated Vasculitis Superimposed on Infection-related Glomerulonephritis Secondary to Pulmonary Mycobacterium avium Complex Infection

A 73-year-old woman was diagnosed with pulmonary Mycobacterium avium complex (MAC) infection and received no treatment. Disease progression was evident one year later with the development of myeloperoxidase-antineutrophil cytoplasmic antibody (ANCA) titers and systemic symptoms of a fever, polyarthritis, purpura, and rapidly progressive glomerulonephritis. Her symptoms did not improve with antibiotic treatment. A renal biopsy revealed crescentic glomerulonephritis with immunodeposition. According to these findings, she was diagnosed with ANCA-associated vasculitis (AAV) superimposed on infection-related glomerulonephritis (IRGN). Although there was a risk of aggravating an underlying infection, the combination therapy of corticosteroid and antibiotics improved AAV, IRGN, and even the lung radiological findings. To the best of our knowledge, this is the first case of AAV and IRGN secondary to pulmonary MAC infection.

Impact of Airflow Limitation on Carotid Atherosclerosis in Coronary Artery Disease Patients

Background: Both airflow limitation and smoking are established cardiovascular risk factors. However, their interaction as risk factors for the development of atherosclerosis in coronary artery disease patients remains unclear. Objectives: To evaluate the effect of the interaction between airflow limitation and smoking status on the severity of carotid atherosclerosis. Methods: We categorized the 234 enrolled patients with coronary artery disease into four groups: never-smokers with normal pulmonary function (group A), never-smokers with airflow limitation (group B), ever-smokers with normal pulmonary function (group C), and ever-smokers with airflow limitation (group D). Results: The prevalence of airflow limitation in the enrolled patients was 23.1% (ever-smokers: 15.8%, never-smokers: 7.3%). The prevalence of severe carotid atherosclerosis was 28.2, 29.4, 41.3, and 45.9%, respectively, in the four groups (group D vs. group A, p = 0.035). Even after multivariate adjusting for confounding factors, ever-smokers with airflow limitation were independently associated with severe carotid atherosclerosis (odds ratio 2.89, 95% confidence interval, 1.19-7.00, p = 0.019). Conclusions: Ever-smokers with airflow limitation were significantly associated with severe carotid atherosclerosis among patients with coronary artery disease. These findings also provide additional insight into the correlation between airflow limitation and poor cardiovascular clinical outcomes.

Joint Annual Meeting of the Swiss Society for Allergology and Immunology and the Swiss Respiratory Society, Bern, April 17-19, 2013

Introduction Bioaerosols such as grain dust (GD) elicit direct immunological reactions within the human respiratory system. Workplace-dependent exposure to GD may induce asthma, chronic bronchitis, and hypersensitivity pneumonitis. Aims To assess the clinical impact of occupational exposure to GD and to determine quantitative biological markers of bioaerosol exposure in grain workers. Methods This longitudinal study has been conducted from summer 2012 to summer 2013, comprising 6 groups of 30 active workers with different GD exposure patterns (4 groups of grain workers, 2 control groups). Two evaluations at high- and low-exposing seasons take place, during which an occupational and a medical history are questionnaire-assessed, lung function is evaluated by spirometry, airway inflammation is measured by exhaled nitric oxide (eNO) and specific blood IgG and IgE are titrated. Results The preliminary results are those of 2 of the 4 exposed groups, (harvesters and mill workers), compared to the control groups, at first assessment (n=100). Mean age is 38.4 [years]; 98% are male. Exposed groups differ from controls (p Conclusion Preliminary results show a higher prevalence of clinical symptoms and a lower mean PEF value in the groups exposed to GD.