Kazutaka Mori

Colored 3-Dimensional Analyses of Respiratory Resistance and Reactance in COPD and Asthma

Background: The forced oscillation technique (FOT) is a noninvasive method with which to measure respiratory system resistance (Rrs) and reactance (Xrs) at a wide range of frequencies during breathing at rest in a short time. The purpose of this study was to assess the differences in Rrs and Xrs between patients with chronic obstructive pulmonary disease (COPD) and asthma using a new method of FOT with colored 3-dimensional visualization. Methods: Fifty-one patients with stable COPD and 49 patients with controlled or partly controlled asthma were enrolled. Whole-breath or within-breath changes of Rrs and Xrs were measured and compared between the diseases. Results: The colored 3-dimensional images clarified the complex oscillatory properties of the respiratory system. Whole-breath resistance (the difference in Rrs at 5 and 20 Hz) and reactance (Xrs at 5 Hz and resonant frequency), and within-breath changes in reactance (Xrs at 5 Hz and resonant frequency) discriminated between patients with COPD and asthma. In multivariate regression analyses, inspiratory-expiratory differences in Xrs at 5 Hz contributed significantly to the differentiation between COPD and asthma, independent of age, gender, body weight, and pulmonary function. Conclusion: This new method of FOT is useful in the differential diagnosis of COPD and asthma.

Respiratory mechanics measured by forced oscillation technique in combined pulmonary fibrosis and emphysema.

The coexistence of emphysema and pulmonary fibrosis is known as combined pulmonary fibrosis and emphysema (CPFE). The aim of this study was to compare the lung mechanics measured by multi-frequency forced oscillation technique (FOT) among patients with CPFE, interstitial pneumonia (IP), and chronic obstructive pulmonary disease (COPD). FOT and pulmonary function tests were performed in 41 patients with CPFE, 47 with IP, and 86 with COPD. Whole-breath resistance at 20 Hz was significantly lower in patients with CPFE than in those with IP or COPD, irrespective of the severity of airflow limitation. Within-breath analyses of resistance revealed no difference among the 3 groups; however, the difference between inspiratory and expiratory phases of reactance at 5 Hz, which reflects expiratory flow limitation, in patients with CPFE was significantly higher than in those with IP and lower than in those with COPD. In conclusion, both emphysema and fibrosis affect lung mechanics in CPFE, leading to different findings from IP or COPD alone.

Respiratory mechanics and peripheral airway inflammation and dysfunction in asthma

Clinical application of the forced oscillation technique (FOT) has progressed with the spread of commercially available FOT devices. The correlation between respiratory impedance and spirometry has been reported; however, the association with airway inflammation and pulmonary function, in the lung periphery in particular, is unclear.

Clinical significance of PD-L1 and PD-L2 copy number gains in non-small-cell lung cancer

New reliable biomarkers are needed to predict the response to immune checkpoint inhibitors against programmed death-1 (PD-1) and its ligand (PD-L1), because PD-L1 expression on tumor cells has limited power for selecting patients who may benefit from such therapy. Here we investigated the significance of PD-L1 and PD-L2 gene copy number gains using fluorescence in situ hybridization as well as PD-L1 and PD-L2 expression in 654 patients with resected non-small-cell lung cancer. The prevalence of PD-L1 amplification and polysomy was 3.1% and 13.2%, respectively. The PD-L1 gene copy number status was in agreement with both the PD-L2 and Janus kinase 2 gene copy number statuses. PD-L1 and PD-L2 expression was observed in 30.7% and 13.1%, respectively. Both PD-L1 copy number gains and expression were associated with smoking-related tumors. Tumor cells with PD-L1 genomic gains exhibited significantly higher levels of PD-L1 expression than those without, but PD-L2 copy number gains were not related to PD-L2 augmentation. PD-L1 gene amplification and polysomy were independently associated with PD-L1 expression, with high immune infiltrates and EGFR expression in a multivariate logistic regression model. Comparative analysis between primary tumors and synchronous regional lymph node metastases revealed that the PD-L1 gene copy number alterations were highly consistent and reproducible compared with the PD-L1 expression. Both PD-L1 amplification and level of protein expression were predictors of poor survival using Cox univariate analyses. Therefore, we conclude that an increase in PD-L1 gene copy number can be a feasible alternative biomarker for predicting response to anti-PD-1/PD-L1 therapy.

Toll-Like Receptor–Mediated Airway IL-17C Enhances Epithelial Host Defense in an Autocrine/Paracrine Manner

IL-17A, IL-17F, and IL-25 belong to the IL-17 family of cytokines, and are well known to play important roles in the host defense against infection and inflammatory diseases. IL-17C, also a member of the IL-17 family, is highly expressed in the epithelium; however, the function and regulatory mechanism of IL-17C in airway epithelium remain poorly understood. In this study, we demonstrate that polyinosinic-polycytidylic acid (polyI:C), the ligand to Toll-like receptor 3, is a potent inducer of IL-17C mRNA and protein expression in primary normal human bronchial epithelial (NHBE) cells. IL-17C induction by polyI:C was both time dependent and dose dependent, and was attenuated by inhibitors of the Toll-IL-1 receptor domain-containing adaptor-inducing INF-β (TRIF)-NF-κB pathway, Pepinh-TRIF, BAY11, NF-κB inhibitor III, and NF-κB p65 small interfering RNA, suggesting that IL-17C expression is induced by polyI:C via the Toll-like receptor 3-TRIF-NF-κB pathway. Both IL-17C and polyI:C increased the expression of antimicrobial peptides and proinflammatory cytokines, such as human β-defensin (hBD) 2, colony-stimulating factor 3 (CSF3), and S100A12 in NHBE cells. Knockdown of IL-17 receptor (IL-17R) E, the specific receptor for IL-17C, using IL-17RE small interfering RNA, attenuated polyI:C-induced hBD2, CSF3, and S100A12 expression, without any reduction of polyI:C-induced IL-17C expression, which suggest that IL-17C enhances hBD2, CSF, and S100A12 expression in an autocrine/paracrine manner in NHBE cells. Knockdown of IL-17C also decreased polyI:C-induced hBD2, CSF3, and S100A12 expression. Thus, our data demonstrate that IL-17C is an essential epithelial cell-derived cytokine that enhances mucosal host defense responses in a unique autocrine/paracrine manner in the airway epithelium.

Predictors of phase III slope of nitrogen single-breath washout in COPD

The nitrogen (N₂) single-breath washout (SBW) test is a measure of ventilation distribution inhomogeneity and also a small airway function that offers complementary information to spirometry; however, the relevance to the forced oscillation technique (FOT) and pulmonary emphysema in COPD is not fully understood. We hypothesized that pulmonary functions, forced oscillatory parameters, and emphysema extent would contribute independently to the results of the SBW test. In this cross-sectional study we assessed the relationship between the phase III slope (delta N₂) derived from N₂ SBW and these parameters. Spirometry, lung volumes, N₂ SBW, and the broadband frequency FOT were performed in 56 patients with COPD. Emphysema extent was measured by high-resolution computed tomography and scored. In multiple regression analyses, the delta N₂ was independently predicted by forced vital capacity, resonant frequency, and emphysema score (R(2)=0.57, p<0.0001). The degree of ventilation inhomogeneity derived from N₂ SBW is independently predicted by spirometry, lung mechanics, and the degree of emphysema.

Usefulness of Colored 3D Imaging of Respiratory Impedance in Asthma

Purpose Recently, the clinical application of the forced oscillation technique (FOT) has progressed with the spread of commercially available FOT devices, including the impulse oscillation system and MostGraph. We investigated the usefulness of color 3D imaging of respiratory impedance in asthma using MostGraph. Methods Whole-breath and within-breath respiratory system resistance (Rrs) and reactance (Xrs) were measured in 78 patients with asthma. Color 3D images were classified into three patterns: the chronic obstructive pulmonary disease (COPD)-like pattern (high values of Rrs and Xrs with a marked respiratory cycle and frequency dependence), the asthma pattern (moderately high Rrs over the entire frequency and a respiratory cycle with slight Xrs changes), and a normal-like pattern (low Rrs and Xrs with few within-breath changes). The classification was performed by three researchers, who were unaware of the clinical information, and the clinical characteristics were compared among the three groups. Results Color 3D imaging provided a COPD-like pattern in 25 patients, an asthma pattern in 39 patients, and a normal-like pattern in 14 patients. Patients with the COPD-like pattern were predominantly female with a higher body mass index, lower forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), and higher Rrs and Xrs values (whole-breath and within-breath variation). Those with the normal pattern had higher FEV1 and FVC, and a lower single-breath nitrogen washout slope. There were no differences in asthma control or exhaled nitric oxide levels among the three groups. Conclusions These results suggest that color 3D imaging of respiratory impedance may show asthma phenotypes.

Synergistic Proinflammatory Responses by IL-17A and Toll-Like Receptor 3 in Human Airway Epithelial Cells

Viral respiratory infections activate the innate immune response in the airway epithelium through Toll-like receptors (TLRs) and induce airway inflammation, which causes acute exacerbation of asthma. Although increases in IL-17A expression were observed in the airway of severe asthma patients, the interaction between IL-17A and TLR activation in airway epithelium remains poorly understood. In this study, we demonstrated that IL-17A and polyI:C, the ligand of TLR3, synergistically induced the expression of proinflammatory cytokines and chemokines (G-CSF, IL-8, CXCL1, CXCL5, IL-1F9), but not type I interferon (IFN-α1, -β) in primary culture of normal human bronchial epithelial cells. Synergistic induction after co-stimulation with IL-17A and polyI:C was observed from 2 to 24 hours after stimulation. Treatment with cycloheximide or actinomycin D had no effect, suggesting that the synergistic induction occurred without de novo protein synthesis or mRNA stabilization. Inhibition of the TLR3, TLR/TIR-domain-containing adaptor-inducing interferon β (TRIF), NF-κB, and IRF3 pathways decreased the polyI:C- and IL-17A/polyI:C-induced G-CSF and IL-8 mRNA expression. Comparing the levels of mRNA induction between co-treatment with IL-17A/polyI:C and treatment with polyI:C alone, blocking the of NF-κB pathway significantly attenuated the observed synergism. In western blotting analysis, activation of both NF-κB and IRF3 was observed in treatment with polyI:C and co-treatment with IL-17A/polyI:C; moreover, co-treatment with IL-17A/polyI:C augmented IκB-α phosphorylation as compared to polyI:C treatment alone. Collectively, these findings indicate that IL-17A and TLR3 activation cooperate to induce proinflammatory responses in the airway epithelium via TLR3/TRIF-mediated NF-κB/IRF3 activation, and that enhanced activation of the NF-κB pathway plays an essential role in synergistic induction after co-treatment with IL-17A and polyI:C in vitro.

Respiratory impedance is correlated with morphological changes in the lungs on three-dimensional CT in patients with COPD

The forced oscillation technique provides information concerning respiratory impedance, which comprises resistance and reactance of the respiratory system. However, its relationship with morphological changes of the lungs in chronic obstructive pulmonary disease (COPD) remains unclear. Respiratory impedance and spirometric data were evaluated in 98 patients with COPD and 49 reference subjects. Wall thickness (WT) and airway intraluminal area (Ai) of third- to sixth-generation bronchi, and percentage low-attenuation area with less than −950 HU (%LAA) of lungs were measured using three-dimensional computed tomography. COPD patients had higher respiratory impedance, decreased Ai, and increased %LAA compared with reference subjects. Indices of respiratory resistance and reactance and forced expiratory volume in 1 second (FEV1) were correlated with Ai, and the association between percent predicted FEV1 and Ai was predominant in distal bronchi. The difference in respiratory resistance between 5 Hz and 20 Hz (R5–R20) and FEV1/forced vital capacity ratio (FEV1/FVC) were correlated with WT. The %LAA was correlated with the FEV1/FVC ratio and respiratory reactance. Airway function measurements with the forced oscillation technique provide complementary information to spirometry in COPD.

Inspiratory resonant frequency of forced oscillation technique as a predictor of the composite physiologic index in interstitial lung disease

The composite physiologic index (CPI), which is derived from FEV1, FVC, and diffusing capacity, has been developed to predict the extent of fibrosis on high-resolution computed tomography (HRCT). However, the relevance to the forced oscillation technique (FOT) is not fully understood. We hypothesized that FOT would independently predict the CPI in interstitial lung disease (ILD). In this cross-sectional study we assessed the relationship between pulmonary function tests, forced oscillatory parameters, and the degree of fibrosis in ILD. Spirometry, evaluation of diffusing capacity for carbon monoxide, and the broadband frequency FOT were performed in 93 patients with a clinical/HRCT diagnosis of ILD. The CPI was calculated and fibrosis extent was measured by HRCT and scored. Univariate analyses revealed that, of the forced oscillatory parameters, inspiratory resonant frequency best correlated with FVC, FEV1, diffusing capacity, CPI, and fibrosis score. In multiple regression analyses, CPI was independently predicted by inspiratory resonant frequency and fibrosis score (model R(2)=0.405, p<0.0001).