Citations

Abstract RATIONALE: Clinical practice guidelines recommend that mechanically ventilated patients (MVPs) receiving sedative therapy achieve a target goal of ‘awake and calm’ when medically possible. However, ICU sedation practices rely on clinicians’ administration of medications based on observations of patients’ arousal/motor activity that are not consistently based on symptom assessments nor consider patients’ preferences. We hypothesized that MVPs would safely self-manage sedative therapy (SMST) base on individual needs and perceived anxiety while experiencing less sedative exposure and delirium. METHODS: A two-group randomized clinical trial conducted in two Midwestern academic medical centers enrolled 161 MVPs willing and able to depress a medication delivery push-button device who remained on protocol for 7 days or until extubated, withdrew or died. Control group (CG) patients (n=81) received sedative medications administered by ICU nurses per unit protocols. Experimental SMST group patients (n=80) received a basal infusion of dexmedetomidine (0.2 mcg/kg/hr titrated per algorithm) + self-administered bolus doses (0.25 mcg/kg up to 3/hour). Primary outcomes were anxiety ratings using a 100-mm visual analog scale (VAS-A), sedation intensity score (aggregate summary of 9 intravenous sedative/opioid medications received range 0-36), and incidence of delirium using the CAM-ICU. Analyses were descriptive and parametric statistics and Generalized Estimating Equations. RESULTS: Patients were predominantly White (93%) females (55%), mean age 58.9+15.1 years receiving mechanical ventilation for respiratory failure (60%) with mean APACHE III of 84.5 + 32.5. Anxiety was highly variable over time wherein patients in both groups endorsed the full range from 0-100. VAS-A over time between groups was -0.06 (p=0.98) indicating that anxiety was 0.06 units lower for SMST patients versus CG. Median sedation intensity in SMST group 11.8 + 9.6, compared to CG 12.7 + 9.6 (p = 0.55) over 7 days. 10.2% of SMST patients had one or more incident delirium events compared to 8.5% of CG (p =.97). Hypotension was experienced equally between groups: 22 in SMST, 23 in CG (p = 1.0) as were device disruptions: 2 in SMST versus 3 in CG (p = 1.0). 82% of SMST were satisfied/very satisfied with ability to self-administer dexmedetomidine; 70% were satisfied/very satisfied with ability to control anxiety; 68% were satisfied/very satisfied with the level of relaxation experienced. CONCLUSIONS: Although there were no significant differences between groups on the primary outcomes, the experimental SMST intervention was safe with high patient-reported satisfaction. SMST may be a viable new paradigm for sedative therapy administration among select ICU patients.

Abstract Rationale: The D'Nerva Targeted Lung Denervation (TLD) System uses radiofrequency energy delivered bronchoscopically to the main bronchi to disrupt parasympathetic nerve innervation to the lung. AIRFLOW-3 clinical trial was a randomized, double blind, sham controlled study to determine the impact of TLD on COPD exacerbations. Methods: AIRFLOW-3 patients had symptomatic COPD (CAT ≥10) with moderate to very severe airflow obstruction (GOLD stage II-IV: 25% ≤ FEV1 ≤ 80% predicted, FEV1/FVC<0.70) and GOLD E status (≥2 moderate or ≥1 severe exacerbation in the prior 12 months) despite optimal medical therapy. The primary endpoint was a time-to-first event comparison of the probability of subjects having a moderate or severe exacerbation, between the Treatment arm (TLD + optimal medical therapy) and the Sham Control arm (optimal medical therapy). Results: 388 patients were randomized 1:1 at 32 clinical sites across the US, EU, and UK. Patients were 67.8 (SD 7.1) years of age, ex-smokers with a 46.7 (22.0) pack-year smoking history, and 41.0 (11.8) post bronchodilator FEV1% pred. SGRQ-C and CAT scores were 62.5 (17.0) and 23.6 (6.3), respectively. Over 90% of patients were on triple therapy (LAMA+LABA+ICS) at baseline and through 1 year of follow up. 42% of patients had prior-year COPD hospitalization(s). There was no difference between groups in the analysis of the primary endpoint. At 1 year, the sham arm exhibited a statistical decline in lung function (decrease in FEV1 and FVC) and worsening of gas trapping (increase in RV). Lung function and gas trapping were stable in the treatment arm. The treatment arm exhibited a statistically significant improvement in dyspnea at one year compared to sham (mMRC, and TDI). These observations led to the identification of a subgroup of TLD treatment responders corresponding to an airway predominant phenotype (lung hyperinflation in the absence of significant emphysema) that demonstrated clinically and statistically significant improvements in lung function and exacerbation frequency and severity (Table). Conclusions: The AIRFLOW-3 clinical trial failed to meet its prespecified primary endpoint. Post-hoc analysis of this robust dataset led to the identification of a responder profile that achieved significant and sustained improvements in lung function, and exacerbation reduction. A future clinical study is being designed to confirm these findings.

Abstract Rationale: Asthma involves airway inflammation, hyperresponsiveness (AHR), and remodeling (cell proliferation and fibrosis), with both aspects not fully alleviated by current therapies. GPCR-based drugs represent a major aspect of current asthma therapy. Asthmatic airways express several orphan receptors with unknown physiological roles, highlighting a potentially novel and significant area for therapeutic exploration. Herein, we focus on orphan retinoic acid (RA)-induced Class C GPCR members GPRC5A (RAIG1; 5A) and GPRC5B (RAIG2; 5B). We leveraged recently identified 5A agonists to test the hypothesis that these GPCRs have alleviating effects in airways. Methods: Primary human airway smooth muscle cells (ASM) originating from non-asthmatic (NA) and asthmatic (Asth) individuals were obtained post-surgery from lung tissues after approval by the Mayo Clinic Institutional Review Board. PRESTO-Tango assay was used to determine 5A and 5B activity. cADDis assay was used to assess cAMP levels. Fluorescence imaging was used to determine calcium regulation. Recently identified 5A agonists [tryptamine, 7 fluoro-tryptamine (7FT), L-tryptophan, N-methyltryptamine, and indole-3-acetic acid] were used in assays, along with RA and 5A vs. 5B siRNAs. Results: PRESTO-Tango assay showed that tryptamine (10/100 µM) and 7FT (1/10/100 µM) increased 5A activity while high concentrations of 7FT (100 µM) increased 5B activity as well. cADDis assay showed 100 µM tryptamine increased cAMP more than 1/10 µM tryptamine and that 10 µM 7FT increased cAMP more than 1/100 µM 7FT in NA ASM.Calcium imaging showed that 5A agonist blunts responses to histamine, especially in Asth ASM. Calcium responses were higher in Asth ASM and 5A siRNA-treated ASM while 5B siRNA had an alleviating effect. Conclusions: Class C GPCRs 5A and 5B interestingly have opposing effects in human ASM towards blunting calcium responses to bronchoconstrictor agonists in the context of asthma. Thus, 5A agonists and 5B antagonists may represent novel GPCR-based approaches in airway diseases.

Abstract Rationale: Moderate hyperoxia (<60% O2) in premature infants promotes bronchial airway hyperresponsiveness (AHR) and impaired bronchodilation involving airway smooth muscle (ASM). Understanding mechanisms by which hyperoxia initiates long-term bronchial airway changes in prematurity is critical for novel therapies for wheezing disorders and asthma in children. Underdeveloped lungs in prematurity have immature antioxidant systems, which may be due to disrupted dynamics that promote susceptibility to oxidative stress from O2. Cytoplasmic and mitochondrial calcium signaling mechanisms and O2 metabolism are pathways highly relevant to ASM and airway disease. We propose that the novel gasotransmitter hydrogen sulfide (H2S) attenuates effects of O2 in developing ASM and hypothesize that hyperoxia in prematurity promotes cellular and mitochondrial calcium signaling dysfunction, effects which are counteracted by H2S.Methods: Human fetal (fASM) cells isolated from tracheobronchial samples of de-identified 18-22 week fetuses following fetal demise (Mayo IRB approved as exempt) were exposed to 21% vs 40% O2. fASM were treated 24-72 hours with H2S donor GYY4137, mitochondrial-specific H2S donor AP39, cystathione-β-synthase (CBS) stabilizer AdoMet, cAMP inhibitors SQ22536 or KT5720, or vehicle control (DMSO). CBS shRNA lentiviral particles were used to generate stable knockdown cell lines. Protein markers were measured by Western blot. Intracellular calcium ([Ca2+]i) was measured using 5μM Fura-2/AM and mitochondrial calcium ([Ca2+]m) with 1μM Rhod-2 AM using fluorescence microscopy. Results: CBS expression was lower in fASM exposed to 40% O2 compared to 21% O2. Lentivirus induced CBS KD was exacerbated by 40% O2. Hyperoxia increased [Ca2+]i and [Ca2+]m response to histamine (10μM) in vehicle and Scr controls compared to normoxia. CBS KD increased [Ca2+]i and [Ca2+]m responses to histamine compared to Scr fASM in 21% O2. CBS KD fASM exposed to hyperoxia showed increased [Ca2+]i and [Ca2+]m responses to histamine, but the effect was not amplified by CBS KD. [Ca2+]i and [Ca2+]m responses to histamine were decreased in normoxia by H2S donors GYY4137 (50μM) and AP39 (100nM) and CBS stabilizer AdoMet (100nM); effects which also blunted hyperoxia induced increases. SQ22536 and KT5720 inhibited effects of AP39 and GYY4137 in hyperoxia. Conclusions:Our findings suggest hyperoxia leads to [Ca2+]i and [Ca2+]m dysfunction in developing airway cells, which can be alleviated through modulation of H2S pathways, offering potential targets for future therapies to blunt hyperoxia effects on bronchoconstriction and bronchodilation. Acknowledgment: Supported by AHA Postdoctoral Fellowship 20POST35210002 (Bartman), NIH R01 HL-056470 (Prakash), and HL-160570 (Pabelick).

Abstract Background: Kisspeptins (Kp) are a group of hypothalamic peptides that aid in regulating pubertal development and sex hormone signaling. In our recent studies, we observed the important role of Kp-10 (Kp peptide) and its receptor KISS1R signaling in regulating the airway smooth muscle (ASM) structure and function. In these studies, we observed significantly reduced expression of KISS1R during asthma pathophysiology suggesting a loss of protective mechanism and exogeneous Kp-10 may be protective in the context of asthma. Studies have shown that specific modifications to the amino acids of Kp peptides can result in increased binding efficiency and receptor activation. Accordingly, we developed three novel Kp peptides, named KpSATs (13A, 13B, and 13C), and tested the potential effects/efficiency on ASM cell remodeling. Methods: The Molecular docking of the KpSAT peptides (13A, 13B and 13C) with the receptor KISS1R were performed using HPEPDOCK. KpSATs were synthesized by GenScript (New Jersey, US) with purity of ≥97%. Primary human ASM cells isolated from surgical lung resections (Mayo Clinic IRB-approved) were cultured in DMEM-F12. Cells were treated with PDGF (2ng/mL) and/or TGF-β (2ng/mL) with/without treatments of KpSATs (13A, 13B, and 13C: 250nM-1µM) and Kp-10 (1µM). ASM cell proliferation was measured using MTT. Extracellular matrix (ECM) deposition (fibronectin and collagen-I/III) studies were performed using In-Cell Western (LiCor-odyssey). The mechanistic signaling pathway (phospho-PKC-δ) were measured using Western blot analysis. Results: In the novel KpSATs, we substituted three amino acids in the endogenous Kp-13 sequence, Y10W and P12T for KpSAT-13A; S6A and P12T for KpSAT-13B; and S6A and Y10W for KpSAT-13C. The peptides dock in the orthosteric ligand binding pocket attained with docking scores ranging from -250 to -280. The MTT assay indicated a reduction in PDGF-induced ASM cell proliferation upon exposure to KpSATs. Notably, we found that KpSAT-13A and KpSAT-13B had significant effects in reducing proliferation at lower concentrations of 500nM compared to 1µM of Kp-10. Furthermore, ECM deposition studies showed a significant reduction of TGF-β1-induced collagen-I/III and fibronectin in ASM cells exposed to KpSAT-13A and 13B. In addition, we observed significant inhibition of PDGF-induced phospho-PKC-δ by KpSAT-13A and 13B. Conclusion: Overall, these findings highlight that modification in amino acid sequence in endogenous Kp-13 sequence significantly increases the potency of synthesized novel KpSATs on ASM cells. In addition, KpSATs showed better inhibitory effects with a lower concentration compared to Kp-10 and could be considered as a promising therapeutic strategy to mitigate asthma.

Abstract Rationale: Asthma in the elderly (AIE) presents a unique challenge characterized by hyperreactive and thickened, fibrotic airways (remodeling) that is not adequately addressed by current therapies. Thus, understanding mechanisms that drive AIE become important. Here, airway smooth muscle (ASM) cells play important roles in normal airway physiology and asthma pathophysiology. Recent discoveries have highlighted the significance of mechanosensitive Piezo (Pz) in health and disease. The lung generates mechanical forces of normal breathing and other maneuvers that are transmitted to bronchial airways via tethering parenchyma. While Pz channels are highly expressed in the lung, their specific role in ASM function remains largely unexplored. In this study, we used human ASM cells to test the hypothesis that increased airway stiffness associated with normal aging blunts Pz expression and mechanosensitive functionality, whereas asthmatic triggers (e.g. inflammation) enhance Pz expression and downstream signaling. Methods: Primary human ASM cells isolated from lungs of young (<45y) vs. aged (>65y) non-asthmatic vs. asthmatic individuals were obtained post-surgery (Mayo Clinic IRB approved). Cells were exposed to mechanical stretch (mimicking breathing) and mediators relevant to asthma (TNFα, IL-13) or fibrosis (TGFβ) to determine expression of Pz1/2 across the age spectrum. Separately, intracellular Ca2+ and contractility responses, proliferation and extracellular matrix (ECM) deposition across age/asthma groups were assessed in response to mechanical stretch and Pz1/2 modulation (inhibitors/activators, genetic approaches). Manipulation of Pz1/2 expression or function in ASM accompanied by mechanical stretch was used to assess impact on canonical Wnt/β-catenin signaling. Results: We observed increased Pz1/2 expression with age and asthma as well as with inflammation and mitogenic stimuli. Functionally, Pz1 agonist, Yoda1 induced increase in intracellular Ca2+, ASM proliferation and ECM deposition with greater effects observed in aging asthmatic ASM. Towards linking mechanosensation (via Pz) to remodeling via Wnt signaling, we find that Wnt3a is upregulated by Yoda1 but suppressed by Pz1 shRNA. Yoda1 stimulates TGFβ-induced Wnt3a and β-catenin, an effect further enhanced under mechanical stretch. Conclusions: By elucidating the role of Pz channels in ASM, we aimed to identify novel therapeutic targets for airway diseases. Understanding how mechanical forces and inflammatory stimuli influence Pz-mediated signaling pathways will lead to the development of innovative strategies to prevent or reverse airway remodeling in elderly asthmatic patients. Acknowledgement: Supported by 24POST1241979 (NAB) and NIH grants R01-HL142061 (CMP and YSP), R01- HL088029 (YSP).

Abstract Rationale: In premature infants, continuous positive airway pressure (CPAP) serves as an effective respiratory support strategy in the NICU. However, the static stretch induced by CPAP may negatively impact bronchial airway development, leading to hyperreactivity and remodeling, key proponents of asthma. Here, epithelial and airway smooth muscle cells are affected by stretch, but the mechanisms by which effects occur are not well-known. In airway smooth muscle contractility, stromal interaction molecule 1 (STIM1) at the endoplasmic reticulum and plasma membrane Orai1 channels are important mediators of the store operated calcium entry (SOCE) microdomain signaling pathway, facilitating movement of calcium into the cell and triggering downstream remodeling effects. Recently discovered mechanosensitive Piezo (PZ) channels play a critical role in calcium influx upon mechanical stimulation. In this study, we investigated the hypothesis that interplay between mechanosensitive channels such as PZ and the SOCE microdomain promotes calcium in human fetal airway smooth muscle cells (fASM) towards increasing contractility by stretch. Methods: fASM were obtained from 18-22 week abortus following fetal demise (exempt per Mayo IRB). Cells were pretreated with either PZ1 inhibitor GsMTx4 [1uM] or PZ2 inhibitor D-GsMTx4 [1uM] 45 minutes before stretch. Cells were exposed to normal breathing stretch conditions on a FlexCell System at a 5% cyclic strain (40 cycles/minute) and CPAP with static stretch superimposed for 24 hours. Protein expression of PZ channels and key SOCE proteins were quantified. SOCE responses of stretched and control cells were determined using established protocols in fura-2 loaded cells using fluorescence microscopy. Results: Mechanical stretching of fASM increased protein expression of PZ1, STIM1, and Orai1 in a dose dependent manner. Stretch increased intracellular SOCE responses compared to non-stretched controls. PZ1 antagonist GsMTx4 and PZ2 antagonist D-GsMTx4 inhibited stretch-induced Piezo1, STIM1, and Orai1 upregulation. GsMTx4 and D-GsMTx4 blunted stretch and non-stretched induced calcium SOCE responses relative to unstretched control. Conclusions: Our findings suggest that in the context of mechanical stretch, Piezo channels and the downstream SOCE signaling pathway increase in expression and functionality in the fetal airway which may contribute to CPAP associated changes in airway contractility.

Abstract Rationale: We previously reported (PMID: 38325750) that a nebulized exosome product isolated from human platelets (PEP) attenuated murine cigarette smoke (CS)-induced emphysema. To further elucidate the mechanism by which PEP attenuates CS-induced effects in the murine lung, emphysema was induced, and mice were treated with PEP or placebo (saline). Immune and cellular mechanisms affected by PEP were then evaluated in this system. Methods: C57BL6 female black mice were exposed to CS 5 days a week for 3 months and then randomized into PEP-treated or placebo groups. CS-exposed mice were treated with 3 mL of 7.5 mg/mL PEP (∼1 x 1010 extracellular vesicles per mL) or 0.9% saline by nebulization 3 times a week for an additional 4 weeks, using a nose-sealed, pressure and humidity-controlled inhalation tower for 30 minutes. Lung compliance, cutaneous O2 saturation, mean linear intercepts, and lung inflammation were measured during and after the study. Lung tissue was further analyzed by immunostaining, and gene expression analyses to elucidate the molecular mechanisms of PEP's action. Inflammatory and immune regulatory cell markers evaluated included CD4 (CD4+ T lymphocytes), CD4/Foxp3 (T regulatory – Treg) cells, S100A9 (interstitial lung macrophages), and myeloperoxidase (MPO) for neutrophils. Results: Histologic review of lung tissue sections by mean linear intercept counts confirmed prior findings and showed a significant reduction in the free distance of chronic CS exposure-induced alveolar space enlargement in PEP-treated mice (P=0.003). In addition, lung inflammation scores showed a significant overall reduction of the lymphocytic infiltrates in PEP-nebulized lungs compared to the CS-exposed placebo control group (P<0.0001). Further analysis of the immune cell infiltrates revealed increased FOXP3+CD4+ T regulatory cells within the lymphocytic infiltrates (P<0.0001) and decreased S100A9+ interstitial lung macrophages (p=0.0002) and MPO+ neutrophils (p=0.005) in PEP nebulized lungs compared to the placebo controls. PEP-treated mice had similar oxygen saturation levels when compared to the CS control group (94.7±1.47 vs. 95.4±.1.6 respectively). Conclusions: In addition to validating prior findings on the effect of nebulized PEP in mitigating CS-induced murine lung injury and emphysema, the current data suggests an immunoregulatory role for PEP by decreasing inflammatory macrophage and neutrophil infiltration while augmenting anti-inflammatory Treg cell numbers in the lung.

Abstract Background: Intravenous fluid resuscitation is fundamental for sepsis-induced hypoperfusion. The 2021 Surviving Sepsis Campaign recommends 30 mL/kg of intravenous crystalloid within the first three hours. Fluid management in patients with sepsis is challenging due to risk for volume overload hence edema in the lungs and other organs. Conflicting literature debates over whether liberal or restricted fluid administration is optimal in this population. We hypothesized that, despite X-ray findings suggesting volume overload, liberal fluid resuscitation in patients with severe sepsis or septic shock does not increase in-hospital mortality or ventilation requirements. Methods: The study is approved by the Mayo Clinic IRB. We retrospectively studied adult patients admitted to the medical ICU with severe sepsis or septic shock from 2014-2018. Data collected included admission weight, chest Xray (CXR) fluid status (“wet” vs. “dry”), fluid resuscitation volumes at 3 and 24 hours (liberal [≥30 mL/kg] vs. restricted), in-hospital mortality, ventilation need, ICU/hospital length of stay (LOS), admission lactate, baseline NT-proBNP, home oxygen use, and history of heart failure or chronic pulmonary disease. For accuracy, an independent pulmonologist reviewed CXRs, and patients with radiologist-pulmonologist discrepancies were excluded. Results: Of 346 patients, 68% had “wet” CXRs. Patients with “dry” CXRs received greater median fluid resuscitation at both 3 hours (3913 mL vs. 3126 mL, p=0.001) and 24 hours (6085 mL vs. 5435 mL, p=0.0005). Liberal fluid resuscitation was more frequent in patients with “dry” CXR than those with “wet” CXR (72% vs. 57%, p=0.006). In-hospital mortality was lower among patients receiving liberal resuscitation compared to restricted (13% vs. 21%; OR 0.573, 95% CI 0.32-1.02, p=0.04), although in patients with “wet” CXRs, liberal resuscitation did not significantly impact mortality (p=0.17). Need for invasive or noninvasive ventilation tended to be higher in the restricted group compared to the liberal group, though this was not statistically significant (45% vs. 29%; OR 0.48, 95% CI 0.21-1.12, p=0.07). There was no significant difference in ICU or hospital LOS between patients receiving liberal and restricted resuscitation (p=0.14 and p=0.9, respectively). In multivariate analysis, in-hospital mortality was significantly associated with chronic pulmonary disease (p=0.04) and admission lactate (p=0.007) but not with CXR findings (p=0.72) or fluid resuscitation volume (p=0.38). Additionally, neither CXR findings (p=1) nor liberal fluid resuscitation (p=0.07) significantly increased the need for ventilation. Conclusion: Liberal fluid resuscitation in patients with severe sepsis or septic shock appears safe and does not increase mortality or ventilation needs, even in those with radiographic volume overload.

Abstract Introduction / Rationale Mucus plugs (MPs) on chest computed tomography (CT) are associated with increased respiratory symptoms, worse lung function, and elevated mortality and acute exacerbations among individuals with GOLD2-4 COPD. Whether mucus plug distribution in the upper versus lower lobes differentially impacts future acute exacerbations (AEs) has been incompletely explored. Methods Data from current and former tobacco users, ages 40-80, with ≥10 pack-years, at the enrollment visit in COPDGene were analyzed. MPs were visually-assessed on chest CTs using a sequential reading system; the MP score was calculated as the number of bronchopulmonary segments with plugs (range 0-18). Among subjects with MPs, the percent of lower lobe MPs (%LLMPs) was calculated as the number of bronchopulmonary segments in the right and left lower lobes divided by the total number of bronchopulmonary segments (range 0-100%). Moderate-to-severe AEs were assessed prospectively biannually for up to 15.5 years. Zero-inflated Poisson regression, adjusting for age, sex, BMI, race, smoking status, pack-years, FEV1% predicted, history of AEs (year prior to enrollment), and clinical center assessed the relationship between %LLMPs, total MPs, and prospective AEs; duration of follow-up was included as the offset. Subgroup analyses by lung function category (GOLD0, GOLD 1-4 COPD, and Preserved Ratio Impaired Spirometry, PRISm) were also performed using the same model. Results Among 10,198 tobacco-exposed individuals, 9,406 subjects (mean age 59.7±9.0, 53.4% male, 68% non-Hispanic white) had chest CT scans scored for MPs. The overall prevalence of MP>0 was 30.4%, with an average MP score of 0.78±1.88 and average %LLMP of 48%±39%. The prevalence of MPs varied by lung function category (20.1% GOLD0, 26.2% PRISm, 40.8% COPD) as did the mean MP score (0.28±0.93 GOLD0, 0.49±1.38 PRISm, 1.30±2.42 COPD) (Figure 1). The %LLMP also varied by lung function category (33%±39% GOLD0, 38%±37% PRISm, 57%±37% COPD). Among subjects with MPs>0 (n=2,857), higher %LLMP was associated with a significantly increased risk for future AEs (adjusted rate ratio (aRR) [95%CI]= 1.11[1.05-1.17]; Figure 1). Subgroup analyses by lung function category supported a significant association between increased %LLMP and future AEs in GOLD0 (aRR 1.45 [1.25-1.69]), but not in the COPD or PRISm subgroups (Figure 1). Conclusions A higher proportion of lower lobe mucus plugs is significantly associated with increased risk for future AEs among tobacco-exposed persons. Despite having the lowest burden of MPs, the highest risk for prospective AEs with increasing %LLMP was observed in the subgroup with normal spirometry (GOLD0).