Severity of Airflow Obstruction Based on FEV1/FVC vs FEV1% of Predicted in the General US Population.

RATIONALE: According to GOLD, the ratio of FEV1/FVC is used to confirm airflow obstruction in COPD diagnosis, whereas FEV1% of predicted (FEV1%pred) is used for severity grading. STaging of Airflow obstruction by the FEV1/FVC Ratio (STAR) and its prediction of adverse outcomes has not been evaluated in general populations. OBJECTIVE: To compare the STAR (FEV1/FVC) versus GOLD (FEV1%pred) classification for the severity of airflow limitation in terms of exertional breathlessness and mortality in the general US population. METHODS: Severity stages according to STAR and GOLD were applied to the multi-ethnic National Health and Nutrition Examination Survey (NHANES) 2007-2012 survey including ages 18-80 years, using post-bronchodilatory FEV1/FVC<0.70 to define airflow obstruction in both staging systems. Prevalence of severity stages STAR 1-4 and GOLD 1-4 was calculated and associations with breathlessness and mortality were analyzed by multinomial logistic regression and Cox regression, respectively. RESULTS: STAR versus GOLD severity staging of airflow obstruction showed similar associations with breathlessness and all-cause mortality, regardless of ethnicity/race. In those with airflow obstruction, the correlation between the two classification systems was 0.461 (p<0.001). STAR reclassified 59% of GOLD stage 2 as having mild airflow obstruction (STAR 1). STAR 1 was more clearly differentiated from the non-obstructive compared to GOLD stage 1 in terms of both breathlessness and mortality. CONCLUSIONS: FEV1/FVC and FEV1%pred as measures of severity of airflow limitation show similar prediction of breathlessness and mortality in the adult US population across ethnicity groups. However, stage 1 differed more clearly from non-obstructive based on FEV1/FVC than FEV1%pred. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

Circulating biomarkers of airflow limitation across the life span.

BACKGROUND: Airflow limitation is a hallmark of chronic obstructive pulmonary disease, which can develop through different lung function trajectories across the life span. There is a need for longitudinal studies aimed at identifying circulating biomarkers of airflow limitation across different stages of life. OBJECTIVES: This study sought to identify a signature of serum proteins associated with airflow limitation and evaluate their relation to lung function longitudinally in adults and children. METHODS: This study used data from 3 adult cohorts (TESAOD [Tucson Epidemiological Study of Airway Obstructive Disease], SAPALDIA [Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults], LSC [Lovelace Smoker Cohort]) and 1 birth cohort (TCRS [Tucson Children's Respiratory Study]) (N = 1940). In TESAOD, among 46 circulating proteins, we identified those associated with FEV1/forced vital capacity (FVC) percent (%) predicted levels and generated a score based on the sum of their z-scores. Cross-sectional analyses were used to test the score for association with concomitant lung function. Longitudinal analyses were used to test the score for association with subsequent lung function growth in childhood and decline in adult life. RESULTS: After false discovery rate adjustment, serum levels of 5 proteins (HP, carcinoembryonic antigen, ICAM1, CRP, TIMP1) were associated with percent predicted levels of FEV1/FVC and FEV1 in TESAOD. In cross-sectional multivariate analyses the 5-biomarker score was associated with FEV1 % predicted in all adult cohorts (meta-analyzed FEV1 decrease for 1-SD score increase: -2.9%; 95% CI: -3.9%, -1.9%; P = 2.4 × 10-16). In multivariate longitudinal analyses, the biomarker score at 6 years of age was inversely associated with FEV1 and FEV1/FVC levels attained by young adult life (P = .02 and .005, respectively). In adults, persistently high levels of the biomarker score were associated with subsequent accelerated decline of FEV1 and FEV1/FVC (P = .01 and .001). CONCLUSIONS: A signature of 5 circulating biomarkers of airflow limitation was associated with both impaired lung function growth in childhood and accelerated lung function decline in adult life, indicating that these proteins may be involved in multiple lung function trajectories leading to chronic obstructive pulmonary disease.

Association between periodontal diseases and chronic obstructive pulmonary disease: Evidence from sequential cross-sectional and prospective cohort studies based on UK Biobank.

AIM: To investigate the association between periodontal diseases, airflow limitation and incident chronic obstructive pulmonary disease (COPD) in a large-scale prospective UK Biobank cohort. MATERIALS AND METHODS: Our approach comprised a cross-sectional study and a prospective cohort. Periodontal diseases were determined based on the participants' self-reported dental symptoms, including painful gums, bleeding gums and loose teeth. Logistic regression and Cox proportional hazards models were used to evaluate the association of periodontal diseases with airflow limitation and incident COPD in the cross-sectional study and the prospective cohort, respectively. RESULTS: The cross-sectional study involved 495,610 participants. Multivariable analysis found that periodontal diseases were significantly associated with airflow limitation (odds ratio = 1.036, 95% confidence interval [CI]: 1.015-1.059). The cohort study included 379,266 participants with a median follow-up period of 12.68 years. An elevated risk of incident COPD was associated with the presence of periodontal diseases (hazard ratio: 1.248, 95% CI: 1.174-1.326). The effect was consistent among subgroups, including baseline age (≤65 or >65 years), sex, smoking status and diabetes mellitus. CONCLUSIONS: Periodontal diseases are associated with airflow limitation and elevated COPD incidence. Maintaining good periodontal health in patients with chronic bronchitis and emphysema may help prevent the onset of COPD.

Sustained remission induced by 2 years of treatment with benralizumab in patients with severe eosinophilic asthma and nasal polyposis.

BACKGROUND AND OBJECTIVE: Several randomized controlled trials (RCTs) have shown that benralizumab is characterized by a good profile of efficacy and safety, thereby being potentially able to elicit clinical remission on-treatment of severe eosinophilic asthma (SEA). The main goal of this multicentre observational study was to verify the effectiveness of benralizumab in inducing a sustained remission on-treatment of SEA in patients with or without comorbid chronic rhinosinusitis with nasal polyps (CRSwNP). METHODS: Throughout 2 years of treatment with benralizumab, a four-component evaluation of sustained remission of SEA was performed, including the assessment of SEA exacerbations, use of oral corticosteroids (OCSs), symptom control and lung function. RESULTS: The present study recruited 164 patients suffering from SEA. After 24 months of add-on biological therapy with benralizumab, 69 (42.1%) achieved the important target of sustained remission on-treatment (exacerbation rate = 0, OCS dose = 0, pre-bronchodilator FEV1 ≥80% pred., ACT score ≥ 20). During the same period, a persistent improvement of CRSwNP (SNOT-22 < 30, NP recurrence = 0) was observed in 33 (40.2%) out of 82 subjects with concomitant NP. The latter comorbidity and post-bronchodilator reversibility of airflow limitation were two independent predictors of sustained remission on-treatment (OR = 2.32, p < 0.05 and OR = 5.59, p < 0.01, respectively). CONCLUSION: Taken together, the results of this real-life clinical investigation indicate that benralizumab can induce a sustained remission on-treatment of SEA, especially in those patients with comorbid CRSwNP and reversible airflow limitation.

Association Between Oral Health and Airflow Limitation: Analysis Using a Nationwide Survey in Korea.

BACKGROUND: Although poor oral health is a common comorbidity in individuals with airflow limitation (AFL), few studies have comprehensively evaluated this association. Furthermore, the association between oral health and the severity of AFL has not been well elucidated. METHODS: Using a population-based nationwide survey, we classified individuals according to the presence or absence of AFL defined as pre-bronchodilator forced expiratory volume in 1 second/forced vital capacity < 0.7. Using multivariable logistic regression analyses, we evaluated the association between AFL severity and the number of remaining teeth; the presence of periodontitis; the Decayed, Missing, and Filled Teeth (DMFT) index; and denture wearing. RESULTS: Among the 31,839 participants, 14% had AFL. Compared with the control group, the AFL group had a higher proportion of periodontitis (88.8% vs. 79.4%), complete denture (6.2% vs. 1.6%), and high DMFT index (37.3% vs. 27.8%) (P < 0.001 for all). In multivariable analyses, denture status: removable partial denture (adjusted odds ratio [aOR], 1.12; 95% confidence interval [95% CI], 1.04-1.20) and complete denture (aOR, 1.52; 95% CI, 1.01-2.05), high DMFT index (aOR, 1.13; 95% CI, 1.02-1.24), and fewer permanent teeth (0-19; aOR, 1.32; 95% CI, 1.12-1.52) were significantly associated with AFL. Furthermore, those with severe to very severe AFL had a significantly higher proportion of complete denture (aOR, 2.41; 95% CI, 1.11-3.71) and fewer remaining teeth (0-19; aOR, 2.29; 95% CI, 1.57-3.01). CONCLUSION: Denture wearing, high DMFT index, and fewer permanent teeth are significantly associated with AFL. Furthermore, a reduced number of permanent teeth (0-19) was significantly related to the severity of AFL. Therefore, physicians should pay attention to oral health in managing patients with AFL, such as chronic obstructive pulmonary disease.

Differential role of mucus plugs in asthma: Effects of smoking and association with airway inflammation.

BACKGROUND: The physiological importance of mucus plugs in computed tomography (CT) imaging is being increasingly recognized. However, whether airway inflammation and smoking affect the association between mucus plugs and clinical-physiological outcomes in asthma remains to be elucidated. The objective of this study is to examine how airway inflammation and/or smoking affect the correlation of CT-based mucus plug scores with exacerbation frequency and airflow limitation indices in asthma. METHODS: A total of 168 patients with asthma who underwent chest CT and sputum evaluation were enrolled and classified in eosinophilic asthma (EA; n = 103) and non-eosinophilic asthma (NEA; n = 65) groups based on sputum eosinophil percentage (cut-off: 3%). The mucus plug score was defined as the number of lung segments with mucus plugs seen on CT. RESULTS: More mucus plugs were detected on CT scans in the EA group than in the NEA group, regardless of smoking status. Mucus plug score and exacerbation frequency during one year after enrollment were significantly associated in the EA group but not in the NEA group after adjusting for demographics, blood eosinophil count, and fractional exhaled nitric oxide. Mucus plug score was associated with percentage of predicted forced expiratory volume in 1 s in non-smoking individuals in the EA and NEA group and in smoking individuals in the EA group but not in the NEA group after adjusting for demographics. CONCLUSIONS: The association of mucus plug score with exacerbation frequency and reduced lung function may vary due to airway inflammatory profile and smoking status in asthma.

Mid-childhood fat mass and airflow limitation at 15 years: The mediating role of insulin resistance and C-reactive protein.

BACKGROUND: We previously reported an association of high fat mass levels from age 9 to 15 years with lower forced expiratory flow in 1 s (FEV1 )/forced vital capacity (FVC) ratio (i.e., increased risk of airflow limitation) at 15 years. Here, we aimed to assess whether insulin resistance and C-reactive protein (CRP) at 15 years partially mediate this association. METHODS: We included 2263 children from the UK Avon Longitudinal Study of Parents and Children population-based cohort (ALSPAC). Four fat mass index (FMI) trajectories ("low," "medium-low," "medium-high," "high") from 9 to 15 years were previously identified using Group-Based Trajectory Modeling. Data on CRP, glucose, insulin, and post-bronchodilator FEV1 /FVC were available at 15 years. We defined insulin resistance by the homeostasis model assessment-estimated insulin resistance index (HOMA-IR). We used adjusted linear regression models and a causal mediation analysis to assess the mediating role of HOMA-IR and CRP. RESULTS: Compared to children in the "low" FMI trajectory, children in the "medium-high" and "high" FMI trajectories had lower FEV1 /FVC at 15 years. The percentage of the total effect explained by HOMA-IR was 19.8% [-114.1 to 170.0] and 20.4% [1.6 to 69.0] for the "medium-high" and "high" trajectories, respectively. In contrast, there was little evidence for a mediating role of CRP. CONCLUSION: The association between mid-childhood fat mass and FEV1 /FVC ratio at 15 years may be partially mediated by insulin resistance.

Roles of the physical environment in health-related quality of life in patients with chronic obstructive pulmonary disease.

RATIONALE: Many clinical and psychological factors are known to influence the health-related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD). However, research on whether environmental factors, such as air pollution, noise, temperature, and blue/green spaces also influence HRQL in COPD has not been systematically investigated. OBJECTIVE: To assess the relationship between air pollution, road traffic noise, temperature, and distance to blue/green spaces and respiratory-specific HRQL in COPD. METHODS: We used cross-sectional data from a multicenter study in 407 stable mild-to-very severe COPD patients from Barcelona (Catalonia). Patients answered the COPD Assessment Test (CAT) and Clinical COPD Questionnaire (CCQ). Individual residential exposure to air pollutants (nitrogen dioxide [NO2] and particulate matters of varying aerodynamic diameters [PM2.5, PM10, and PM2.5absorbance]), road traffic noise (Lden), and land surface temperature were estimated using long-term averages from land-use regression models, 24-h noise maps, and land surface temperature maps, respectively. We measured residential distances to blue/green spaces from the Urban Atlas. We used mixed-effect negative binomial (for CAT) and linear (for CCQ) regression models, adjusted for potential confounders, with a random effect by center. RESULTS: Of those patients, 85 % were male and had a mean (SD) age of 69 (9) years, CAT score of 12 (7), CCQ-total score of 1.4 (1.0), and post-bronchodilator forced expiratory volume in 1 s (FEV1) of 57 (18) %predicted. We found that NO2 and PM2.5absorbance were associated with worsened CAT and CCQ-mental scores, e.g., 0.15-unit change in CAT score [regression coefficient (ß) = 0.15; 95 % confidence interval (CI) = 0.03, 0.26] per interquartile range in NO2 [13.7 µg/m3]. Greater distances to blue/green spaces were associated with worsened CCQ-mental scores [0.08; 0.002, 0.15]. CONCLUSIONS: Our study showed that increased air pollution, particularly NO2 and PM2.5absorbance and greater distances to blue/green spaces negatively influence HRQL in COPD patients. These findings have important implications for the WHO promotion to develop healthy cities for our future.

Endotyping Sleep Apnea One Breath at a Time: An Automated Approach for Separating Obstructive from Central Sleep-disordered Breathing.

Rationale: Determining whether an individual has obstructive or central sleep apnea is fundamental to selecting the appropriate treatment. Objectives: Here we derive an automated breath-by-breath probability of obstruction, as a surrogate of gold-standard upper airway resistance, using hallmarks of upper airway obstruction visible on clinical sleep studies. Methods: From five nocturnal polysomnography signals (airflow, thoracic and abdominal effort, oxygen saturation, and snore), nine features were extracted and weighted to derive the breath-by-breath probability of obstruction (Pobs). A development and initial test set of 29 subjects (development = 6, test = 23) (New York, NY) and a second test set of 39 subjects (Solingen, Germany), both with esophageal manometry, were used to develop Pobs and validate it against gold-standard upper airway resistance. A separate dataset of 114 subjects with 2 consecutive nocturnal polysomnographies (New York, NY) without esophageal manometry was used to assess the night-to-night variability of Pobs. Measurements and Main Results: A total of 1,962,229 breaths were analyzed. On a breath-by-breath level, Pobs was strongly correlated with normalized upper airway resistance in both test sets (set 1: cubic adjusted [adj.] R2 = 0.87, P < 0.001, area under the receiver operating characteristic curve = 0.74; set 2: cubic adj. R2 = 0.83, P < 0.001, area under the receiver operating characteristic curve = 0.7). On a subject level, median Pobs was associated with the median normalized upper airway resistance (set 1: linear adj. R2 = 0.59, P < 0.001; set 2: linear adj. R2 = 0.45, P < 0.001). Median Pobs exhibited low night-to-night variability [intraclass correlation(2, 1) = 0.93]. Conclusions: Using nearly 2 million breaths from 182 subjects, we show that breath-by-breath probability of obstruction can reliably predict the overall burden of obstructed breaths in individual subjects and can aid in determining the type of sleep apnea.

Independent Association of Interleukin 6 With Low Dynamic Lung Function and Airflow Limitation in Well-Treated People With Human Immunodeficiency Virus.

BACKGROUND: Human immunodeficiency virus (HIV) infection is associated with an increased risk of chronic pulmonary diseases. We compared cytokine concentrations (interleukin 6 [IL-6], interleukin 1ß, 2, 4, 10, and 17A, tumor necrosis factor α, interferon γ, soluble CD14 [sCD14] and soluble CD163 [sCD163]) in people with HIV (PWH) and uninfected controls and investigated whether elevated cytokine concentrations were independently associated with lung function indices in PWH. METHODS: We performed spirometry and measured cytokine concentrations by Luminex immunoassays or enzyme-linked immunoassay in 951 PWH and 79 uninfected controls from the Copenhagen Comorbidity in HIV Infection study. Regression analyses were used to explore associations between elevated cytokine concentrations and lung function indices. RESULTS: PWH were predominantly male (84.6%) and 94.2% had undetectable viral replication. In PWH, elevated IL-6 was associated with lower forced expiratory volume in 1 second (-212 mL [95% confidence interval, -308 to -116 mL]), lower forced vital capacity (-208 mL [-322 to -93 mL]), and airflow limitation (aOR, 2.62 [1.58-4.36]) (all P < .001) in models adjusted for age, sex, ethnicity, smoking status, body mass index, and CD4 T-cell nadir. The association between IL-6 and dynamic lung function was modified by smoking (P for interaction = .005). CONCLUSION: IL-6 levels were elevated and independently associated with low dynamic lung function and airflow limitation in well-treated PWH, suggesting that systemic inflammation may contribute to the pathogenesis of chronic pulmonary diseases.

Induction of dynamic hyperinflation by expiratory resistance breathing in healthy subjects - an efficacy and safety study.

NEW FINDINGS: What is the central question of this study? The study aimed to establish a novel model to study the chronic obstructive pulmonary disease (COPD)-related cardiopulmonary effects of dynamic hyperinflation in healthy subjects. What is the main finding and its importance? A model of expiratory resistance breathing (ERB) was established in which dynamic hyperinflation was induced in healthy subjects, expressed both by lung volumes and intrathoracic pressures. ERB outperformed existing methods and represents an efficacious model to study cardiopulmonary mechanics of dynamic hyperinflation without potentially confounding factors as present in COPD. ABSTRACT: Dynamic hyperinflation (DH) determines symptoms and prognosis of chronic obstructive pulmonary disease (COPD). The induction of DH is used to study cardiopulmonary mechanics in healthy subjects without COPD-related confounders like inflammation, hypoxic vasoconstriction and rarefication of pulmonary vasculature. Metronome-paced tachypnoea (MPT) has proven effective in inducing DH in healthy subjects, but does not account for airflow limitation. We aimed to establish a novel model incorporating airflow limitation by combining tachypnoea with an expiratory airway stenosis. We investigated this expiratory resistance breathing (ERB) model in 14 healthy subjects using different stenosis diameters to assess a dose-response relationship. Via cross-over design, we compared ERB to MPT in a random sequence. DH was quantified by inspiratory capacity (IC, litres) and intrinsic positive end-expiratory pressure (PEEPi, cmH2 O). ERB induced a stepwise decreasing IC (means (95% CI): tidal breathing: 3.66 (3.45-3.88), ERB 3 mm: 3.33 (1.75-4.91), 2 mm: 2.05 (0.76-3.34), 1.5 mm: 0.73 (0.12-1.58) litres) and increasing PEEPi (tidal breathing: 0.70 (0.50-0.80), ERB 3 mm: 11.1 (7.0-15.2), 2 mm: 22.3 (17.1-27.6), 1.5 mm: 33.4 (3.40-63) cmH2 O). All three MPT patterns increased PEEPi, but to a far lesser extent than ERB. No adverse events during ERB were noted. In conclusion, ERB was proven to be a safe and efficacious model for the induction of DH and might be used for the investigation of cardiopulmonary interaction in healthy subjects.

Real-Life Clinical and Functional Effects of Fluticasone Furoate/Umeclidinium/Vilanterol-Combined Triple Therapy in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: Triple therapy consisting of a drug association including an inhaled corticosteroid, a long-acting muscarinic receptor antagonist and a long-acting ß2-adrenergic agonist, delivered via a single device, can be a valuable treatment for chronic obstructive pulmonary disease (COPD) patients experiencing frequent disease exacerbations. OBJECTIVES: The aim of this real-life, single-center, observational study was to evaluate, in 44 COPD patients with recurrent exacerbations, the effects of the triple inhaled therapy combining fluticasone furoate, umeclidinium, and vilanterol (FF/UMEC/VI). METHODS: Within such a therapeutic context, several clinical and lung functional parameters were considered at baseline and after 24 weeks of treatment with combined inhaled triple therapy. RESULTS: With respect to baseline, after 24 weeks of treatment with FF/UMEC/VI, significant changes were recorded with regard to Modified British Medical Research Council (p < 0.0001) and COPD Assessment Test (p < 0.0001) scores, COPD exacerbations (p < 0.001), forced expiratory volume in the first second (p < 0.001), residual volume (p < 0.01), forced mid-expiratory flow between 25 and 75% of FVC (p < 0.0001), inspiratory capacity (p < 0.01), forced vital capacity (p < 0.05), and peak expiratory flow (p < 0.0001). Moreover, in a subgroup of 28 patients, a significant increase of diffusion lung capacity (p < 0.01) was also detected. CONCLUSIONS: In conclusion, our real-life results suggest that triple inhaled therapy with FF/UMEC/VI, when given to COPD patients with frequent exacerbations, is able to positively impact on dyspnea and global health status as well as to significantly decrease COPD exacerbations and improve airflow limitation and lung hyperinflation.

Fetal Origins of Asthma: A Longitudinal Study from Birth to Age 36 Years.

Rationale: Deficits in infant lung function-including the ratio of the time to reach peak tidal expiratory flow to the total expiratory time (tptef/te) and maximal expiratory flow at FRC (V̇maxFRC)-have been linked to increased risk for childhood asthma.Objectives: To examine the individual and combined effects of tptef/te and V̇maxFRC in infancy on risk for asthma and abnormalities of airway structure into mid-adult life.Methods: One hundred eighty participants in the Tucson Children's Respiratory Study birth cohort had lung function measured by the chest-compression technique in infancy (mean age ± SD: 2.0 ± 1.2 mo). Active asthma was assessed in up to 12 questionnaires between ages 6 and 36 years. Spirometry and chest high-resolution computed tomographic (HRCT) imaging were completed in a subset of participants at age 26. The relations of infant tptef/te and V̇maxFRC to active asthma and airway structural abnormalities into adult life were tested in multivariable mixed models.Measurements and Main Results: After adjustment for covariates, a 1-SD decrease in infant tptef/te and V̇maxFRC was associated with a 70% (P = 0.001) and 55% (P = 0.005) increased risk of active asthma, respectively. These effects were partly independent, and two out of three infants who were in the lowest tertile for both tptef/te and V̇maxFRC developed active asthma by mid-adult life. Infant V̇maxFRC predicted reduced airflow and infant tptef/te reduced HRCT airway caliber at age 26.Conclusions: These findings underscore the long-lasting effects of the fetal origins of asthma, support independent contributions by infant tptef/te and V̇maxFRC to development of asthma, and link deficits at birth in tptef/te with HRCT-assessed structural airway abnormalities in adult life.

Periodontitis and airflow limitation in older Swedish individuals.

AIM: To investigate whether there was an association between periodontitis and airflow limitation in older Swedish individuals. MATERIALS AND METHODS: Study individuals were randomly selected from the Swedish civil registration database representing the ageing population in Karlskrona, Sweden. Clinical and radiographic examinations were performed, alongside which participants completed questionnaires gathering information on their medical history, social circumstances, demographic background and tobacco use. A physical examination assessed anthropometric measures. Standard spirometry was performed to identify subjects with airflow limitation. Periodontitis was defined based on radiographic periodontal bone loss. Analysis included multiple logistic regression with adjustment for various confounders. RESULTS: A total of 826 Caucasian dentate subjects were included in the analysis. The median age of participants was 73.2 (IQR 66-81) years, and 443 (54.6%) subjects were female. Eighty-six (10.4%) individuals presented with airflow limitation. The proportion of participants presenting with periodontitis in the airflow limitation group was 65.1% compared to 41.5% with normal respiratory function (p < .001). Multiple logistic regression analysis showed that periodontitis was independently associated with airflow limitation with an odds ratio of 2.31 (95% CI 1.27-4.22) p < .01. CONCLUSION: In this group of older dentate individuals, periodontitis was significantly associated with airflow limitation independent of other known risk factors.

Correlation of serum fatty acid binding protein-4 and interleukin-6 with airflow limitation and quality of life in stable and acute exacerbation of COPD

Background/aim: The serum fatty acid binding protein 4 (FABP-4) level increases in chronic inflammatory diseases. The present study aimed to examine serum FABP-4 and interleukin (IL)-6 levels in patients with stable and acute exacerbation of chronic obstructive pulmonary disease (COPD) and the correlation of these markers with airflow limitation. Materials and methodsS: We measured serum FABP-4 and IL-6 levels in 60 COPD patients [30 stable COPD (SCOPD), and 30 acute exacerbation of COPD (AECOPD)], and 30 healthy subjects and compared them with airflow limitation according to the COPD stage in the Global Initiative for Chronic Obstructive Pulmonary Disease (GOLD) criteria, peripheral O2 saturation (SpO2), and COPD Assessment Test (CAT) score. We also tested the association between serum FABP-4 levels and some characteristics of study parameters. Results: Both serum FABP-4 and IL-6 levels increased with increasing severity of GOLD grades in SCOPD (P < 0.01 for both) and AECOPD groups (P < 0.001 and P < 0.01, respectively). It also increased in patients with AECOPD group compared with SCOPD group in GOLD grades I-II (P < 0.01) and GOLD grades III-IV (P < 0.05). In addition, there was a significant positive correlation between serum FABP-4 level with IL-6, CAT score, and smoking history and inversely with FEV1 and SpO2. Conclusion: The study revealed that serum FABP-4 level was elevated with increasing GOLD grades in COPD patients, markedly in acute exacerbation phase. The increase was associated with elevated serum levels of IL-6 and severity of hypoxia. Thus, it seems that FABP-4 may be involved in the pathogenesis of COPD.

Mechanical-ventilatory responses to peak and ventilation-matched upper- versus lower-body exercise in normal subjects.

NEW FINDINGS: What is the central question of this study? To what extent are the mechanical-ventilatory responses to upper-body exercise influenced by task-specific locomotor mechanics? What is the main finding and its importance? When compared with lower-body exercise performed at similar ventilations, upper-body exercise was characterized by tidal volume constraint, dynamic lung hyperinflation and an increased propensity towards neuromechanical uncoupling of the respiratory system. Importantly, these responses were independent of respiratory dysfunction and flow limitation. Thus, the mechanical ventilatory responses to upper-body exercise are attributable, in part, to task-specific locomotor mechanics (i.e. non-respiratory loading of the thorax). ABSTRACT: The aim of this study was to determine the extent to which the mechanical ventilatory responses to upper-body exercise are influenced by task-specific locomotor mechanics. Eight healthy men (mean ± SD: age, 24 ± 5 years; mass, 74 ± 11 kg; and stature, 1.79 ± 0.07 m) completed two maximal exercise tests, on separate days, comprising 4 min stepwise increments of 15 W during upper-body exercise (arm-cranking) or 30 W during lower-body exercise (leg-cycling). The tests were repeated at work rates calculated to elicit 20, 40, 60, 80 and 100% of the peak ventilation achieved during arm-cranking ( V̇E,UBE ). Exercise measures included pulmonary ventilation and gas exchange, oesophageal pressure-derived indices of respiratory mechanics, operating lung volumes and expiratory flow limitation. Subjects exhibited normal resting pulmonary function. Arm-crank exercise elicited significantly lower peak values for work rate, O2 uptake, CO2 output, minute ventilation and tidal volume (p < 0.05). At matched ventilations, arm-crank exercise restricted tidal volume expansion relative to leg-cycling exercise at 60% V̇E,UBE (1.74 ± 0.61 versus 2.27 ± 0.68 l, p < 0.001), 80% V̇E,UBE (2.07 ± 0.70 versus 2.52 ± 0.67 l, p < 0.001) and 100% V̇E,UBE (1.97 ± 0.85 versus 2.55 ± 0.72 l, p = 0.002). Despite minimal evidence of expiratory flow limitation, expiratory reserve volume was significantly higher during arm-cranking versus leg-cycling exercise at 100% V̇E,UBE (39 ± 8 versus 29 ± 8% of vital capacity, p = 0.002). At any given ventilation, arm-cranking elicited greater inspiratory effort (oesophageal pressure) relative to thoracic displacement (tidal volume). Arm-cranking exercise is sufficient to provoke respiratory mechanical derangements (restricted tidal volume expansion, dynamic hyperinflation and neuromechanical uncoupling) in subjects with normal pulmonary function and expiratory flow reserve. These responses are likely to be attributable to task-specific locomotor mechanics (i.e. non-respiratory loading of the thorax).

Airway Obstruction in Sleep Apnea Patients.

Obstructive sleep apnea (OSA) is a condition of breathing pathology occurring during sleep, characterized by repeated episodes of upper airway obstruction. The aim of the study was to determine the occurrence of airway obstruction in smoking males with OSA in whom lung function tests had not been performed before. One hundred and four current smokers selected from 1241 patients were enrolled for the research. The subjects included in the study smoked minimum 20 cigarettes a day for at least 10 years. The diagnosis of OSA was confirmed by polysomnography (PSG) in the Sleep Laboratory and subjects were assigned to one of three groups, depending on the severity of OSA. The control group consisted of 30 age-matched male smokers in whom OSA was not confirmed in PSG. Patients from the study and control group scored ≥ 11points in the Epworth Sleepiness Scale. Spirometry, impulse oscillometry, and body plethysmography were used to assess pulmonary function. Airflow limitation in subjects of the control group and OSA patients was confirmed. There were no significant differences in the incidence of bronchial obstruction between the control and study groups, and among the patients of various OSA severity. We conclude that the severity of OSA in smokers does not associate with the presence of airway obstruction. However, the increased peripheral respiratory resistance found in oscillometry did relate to a longer smoking time in OSA patients.

Roles of Periostin in Asthma.

Periostin is a matricellular protein that is deeply involved in type-2/eosinophilic airway inflammation and remodeling in asthma. While its expression in airway epithelial cells is correlated with the thickness of airway basement membrane, more importantly, periostin can be detected stably in blood with little variability, reflecting airway type-2 inflammation and remodeling. As for a result, serum periostin can serve as a valuable marker to identify patients with type-2 severe asthma who are insensitive to inhaled corticosteroids, and consequently have the excess decline of pulmonary function with asthma exacerbations. Serum periostin may significantly help to improve management of patients with severe asthma.

Obstruction phenotype as a predictor of asthma severity and instability in children.

BACKGROUND: Small-airways instability resulting in premature airway closure has been recognized as a risk for asthma severity and poor control. Although spirometry has limited sensitivity for detecting small-airways dysfunction, a focus on the air-trapping component of obstruction might identify a risk factor for asthma instability. OBJECTIVE: We sought to use spirometric measurements to identify patterns of airway obstruction in children and define obstruction phenotypes that relate to asthma instability. METHODS: Prebronchodilation and postbronchodilation spirometric data were obtained from 560 children in the Asthma Phenotypes in the Inner City study. An air-trapping obstruction phenotype (A Trpg) was defined as a forced vital capacity (FVC) z score of less than -1.64 or an increase in FVC of 10% of predicted value or greater with bronchodilation. The airflow limitation phenotype (A Limit) had an FEV1/FVC z score of less than -1.64 but not A Trpg. The no airflow limitation or air-trapping criteria (None) phenotype had neither A Trpg nor A Limit. The 3 obstruction phenotypes were assessed as predictors of number of exacerbations, asthma severity, and airway lability. RESULTS: Patients with the A Trpg phenotype (14% of the cohort) had more exacerbations during the 12-month study compared with those with the A Limit (P < .03) and None (P < .001) phenotypes. Patients with the A Trpg phenotype also had the highest Composite Asthma Severity Index score, the highest asthma treatment step, the greatest variability in FEV1 over time, and the greatest sensitivity to methacholine challenge. CONCLUSIONS: A Trpg and A Limit patterns of obstruction, as defined by using routine spirometric measurements, can identify obstruction phenotypes that are indicators of risk for asthma severity and instability.