Diversity of respiratory impedance based on quantitative computed tomography in patients with COPD

Wada, Yosuke; Kitaguchi, Yoshiaki; Matsumura, Yasuo; Ueno, Fumika; Kawakami, Satoshi; Fukushima, Kiyoyasu; Hanaoka, Masayuki

doi:10.2147/copd.s163129

Cited by 12 publications

(13 citation statements)

References 29 publications

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“…) and these phenotypes also reflect differences in lung biomechanics and function (Wada et al. ). We observed differences in the relationships between VDP and oscillometry measurements in COPD patients with and without emphysema, although it is likely that all COPD patients had airways disease too.…”

Section: Discussionmentioning

confidence: 99%

“…) and there are differences in the relationships between CT measurements and respiratory impedance in different COPD phenotypes (Wada et al. ). Magnetic resonance imaging (MRI) using inhaled noble gases was also recently used to discern the relationships between low‐frequency resistance and elastance as well as the frequency dependence of resistance with MRI signal intensity coefficients of variation (Lui et al.…”

Section: Introductionmentioning

confidence: 99%

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Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD

et al. 2019

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Developed over six decades ago, pulmonary oscillometry has re‐emerged as a noninvasive and effort‐independent method for evaluating respiratory‐system impedance in patients with obstructive lung disease. Here, we evaluated the relationships between hyperpolarized 3He ventilation‐defect‐percent (VDP) and respiratory‐system resistance, reactance and reactance area (AX) measurements in 175 participants including 42 never‐smokers without respiratory disease, 56 ex‐smokers with chronic‐obstructive‐pulmonary‐disease (COPD), 28 ex‐smokers without COPD and 49 asthmatic never‐smokers. COPD participants were dichotomized based on x‐ray computed‐tomography (CT) evidence of emphysema (relative‐area CT‐density‐histogram ≤ 950HU (RA 950) ≥ 6.8%). In asthma and COPD subgroups, MRI VDP was significantly related to the frequency‐dependence of resistance (R 5‐19; asthma: ρ = 0.48, P = 0.0005; COPD: ρ = 0.45, P = 0.0004), reactance at 5 Hz (X 5: asthma, ρ = −0.41, P = 0.004; COPD: ρ = −0.38, P = 0.004) and AX (asthma: ρ = 0.47, P = 0.0007; COPD: ρ = 0.43, P = 0.0009). MRI VDP was also significantly related to R 5‐19 in COPD participants without emphysema (ρ = 0.54, P = 0.008), and to X 5 in COPD participants with emphysema (ρ = −0.36, P = 0.04). AX was weakly related to VDP in asthma (ρ = 0.47, P = 0.0007) and COPD participants with (ρ = 0.39, P = 0.02) and without (ρ = 0.43, P = 0.04) emphysema. AX is sensitive to obstruction but not specific to the type of obstruction, whereas the different relationships for MRI VDP with R 5‐19 and X 5 may reflect the different airway and parenchymal disease‐specific biomechanical abnormalities that lead to ventilation defects.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD

et al. 2019

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“…From the above evidence, the parameters of FOT hardly reflected the decreased lung elastic recoil pressure represented by Cst. Wada et al11 quantitatively evaluated both emphysematous and airway lesions in COPD patients by HRCT, and examined the relationships with indices of respiratory impedance. They reported that R5, R20, and X5 were correlated with airway wall thickening, but not with emphysematous lesions, and that the indices of FOT reflected the extent of airway lesions.…”

Section: Discussionmentioning

confidence: 99%

“…However, the changes in resistance and reactance at lower frequency in these two disease conditions are qualitatively similar. Wada et al11 reported that there were no significant correlations between FOT parameters and the degree of emphysema on high-resolution computed tomography (HRCT). Thus, it has been suggested that the increased Rrs and more negative shift of Xrs at lower frequency may be not a measure of lung compliance.…”

Section: Introductionmentioning

confidence: 99%

<p>Comparison of impedance measured by the forced oscillation technique and pulmonary functions, including static lung compliance, in obstructive and interstitial lung disease</p>

Takeichi¹,

Yamazaki²

2019

COPD

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Objective: To examine whether the parameters of impedance measured by the broadband frequency forced oscillation technique (FOT) were reflected by changes in lung compliance induced by emphysema and fibrosis, we retrospectively compared the parameters of FOT and pulmonary functions, including static lung compliance (Cst), in obstructive lung disease (OLD) and interstitial lung disease (ILD). Patients and methods: The data of 18 patients with OLD (16 with COPD, two with asthma COPD overlap), 11 with ILD, and 24 healthy volunteers, whose respiratory impedance was measured using a MostGraph-01 and other pulmonary functions including Cst and lung resistance (R L ) were measured on the same day and were retrospectively collected and compared. Results: The parameters of resistance, reactance, and resonant frequency showed good correlations with ventilation unevenness ( r =0.63, −0.89, 0.77, respectively) and lung elastic resistance ( r =0.59, −0.80, 0.73, respectively) in all groups (N=53). These indices were significant determinants of increased respiratory resistance and more negative shift of respiratory reactance (Xrs) at lower frequency ( P <0.001). Decreased functional residual capacity was also a determinant of Xrs at 5 Hz (X5) ( P <0.05). The differences in mean X5 in the expiratory phase relative to those in the inspiratory phase (within-breath changes in X5) were associated with airflow obstruction ( P <0.002) and lung elastic resistance ( P <0.001). However, no significant correlations between Cst and any parameters of respiratory impedance were observed. Conclusions: These findings suggest that the impedance parameters measured by FOT are reflected by airway obstruction, ventilation unevenness, and lung resistance, but hardly reflected by changes in lung compliance due to emphysema or fibrosis in both CLD and ILD.

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“…Chronic obstructive pulmonary disease (COPD) is a severe respiratory disease characterized by chronic respiratory syndrome and airway limitation, the pulmonary functional decline is progressive and ultimately results in respiratory failure. The two main pathologic manifestations of COPD—emphysema and airway-vessel remodeling—determine the phenotype of the disease (Wada et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

Ursolic Acid Protected Lung of Rats From Damage Induced by Cigarette Smoke Extract

Hou

Han

et al. 2019

Front. Pharmacol.

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Background: We found previously that ursolic acid (UA) administration could alleviate cigarette smoke-induced emphysema in rats partly through the unfolded protein response (UPR) PERK-CHOP and Nrf2 pathways, thus alleviating endoplasmic reticulum stress (ERS)-associated oxidative stress and cell apoptosis. We hypothesized that other UPR pathways may play similar roles in cigarette smoke extract (CSE)-induced emphysema. So, we sought to investigate the dynamic changes and effects of UPR and the downstream apoptotic pathways. Further, we investigated whether UA could alleviate CSE-induced emphysema and airway remodelling in rats, whether and when it exerts its effects through UPR pathways as well as Smads pathways. Methods: One hundred eight Sprague Dawley (SD) rats were randomly divided into three groups: Sham group, CSE group, and UA group, and each group was further divided into three subgroups, administered CSE (vehicle) for 2, 3, or 4 weeks; each subgroup had 12 rats. We examined pathological changes, analyzed the three UPR signaling pathways and subsequent ERS, intrinsic and extrinsic apoptotic pathway indicators, as well as activation of Smad2,3 molecules in rat lungs. Results: Exposure to CSE for 3 or 4 weeks could apparently induce emphysema and airway remodeling in rats, including gross and microscopic changes, alteration of mean alveolar number (MAN), mean linear intercept (MLI), and mean airway thickness in lung tissue sections. UA intervention could significantly alleviate CSE-induced emphysema and airway remodeling in rats. UA exerted its effects through ameliorating apoptosis by down regulating UPR signalling pathways and subsequent apoptosis pathways, as well as, downregulating p-Smad2 and p-Smad3 molecules. Conclusions: UA attenuated CSE-induced emphysema and airway remodeling, exerting its effects partly through regulation of three UPR pathways, amelioration downstream apoptotic pathways, and alleviating activation of Smad2 and Smad3.

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Diversity of respiratory impedance based on quantitative computed tomography in patients with COPD

Cited by 12 publications

References 29 publications

Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD

Oscillometry and pulmonary magnetic resonance imaging in asthma and COPD

<p>Comparison of impedance measured by the forced oscillation technique and pulmonary functions, including static lung compliance, in obstructive and interstitial lung disease</p>

Ursolic Acid Protected Lung of Rats From Damage Induced by Cigarette Smoke Extract

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