High levels of interleukin-6 and 8-iso-prostaglandin in the exhaled breath condensate and serum of patients with chronic obstructive pulmonary disease related pulmonary hypertension

Background Pulmonary hypertension （PH） is a common complication of chronic obstructive pulmonary disease （COPD）. Although alveolar hypoxia is considered as a main cause of PH in COPD, structural and functional changes of pulmonary circulation are apparent at the initial stage of COPD. We hypothesized that an inflammatory response and oxidative stress might contribute to the formation of PH in COPD. Methods We measured the levels of interleukin-6 （IL-6） and 8-iso-prostaglandin （8-iso-PSG） in exhaled breath condensate （EBC） and serum in 40 patients with COPD only or in 45 patients with COPD combined with PH. Pulmonary arterial systolic pressure （PASP） was assessed by Doppler echocardiography and defined as PH when the value of systolic pressure was greater than 40 mmHg. Results Compared with the COPD only group, the level of IL-6 in EBC was significantly increased in all 45 patients with COPD combined with PH （（8.27±2.14） ng/L vs. （4.95±1.19） ng/L, P 〈0.01）. The level of IL-6 in serum was also elevated in patients with COPD combined with PH compared with the COPD only group （（72.8±21.6） ng/L vs. （43.58±13.38） ng/L, P 〈0.01 ）. Similarly, we also observed a significant increase in the level of 8-iso-PSG in both EBC and serum in the COPD with PH group, compared with the COPD only group （EBC： （9.00±2.49） ng/L vs. （5.96±2.31） ng/L, P 〈0.01 and serum： （41.87±9.75） ng/L vs. （27.79±11.09） ng/L, P 〈0.01）. Additionally, the value of PASP in the PH group was confirmed to be positively correlated with the increase in the levels of IL-6 and 8-iso-PSG in both EBC and serum （r=0.477-0.589, P 〈0.05）. Conclusion The increase in the levels of IL-6 and 8-iso-PSG in EBC and serum correlates with the pathogenesis of PH in COPD.

Effect of Inhaled Budesonide on Interleukin-4 and Interleukin-6 in Exhaled Breath Condensate of Asthmatic Patients

Background： Studies of interleukin （IL）-4 and IL-6 in the exhaled breath condensate （EBC） of asthmatic patients are limited. This study was to determine the effect of inhaled corticosteroid （ICS） treatment on IL-4 and IL-6 in the EBC ＆asthmatic patients. Methods： In a prospective, open-label study, budesonide 200 μg twice daily by dry powder inhaler was administered to 23 adult patients with uncontrolled asthma （mean age 42.7 years） for 12 weeks. Changes in asthma scores, lung function parameters （forced expiratory volume in 1 s [FEV1], peak expiratory flow [PEF], forced expiratory flow at 50% of forced vital capacity [FEFs0], forced expiratory flow at 75% of forced vital capacity, maximum mid-expiratory flow rate） and the concentrations of IL-4 and IL-6 in EBC were measured. Results： Both asthma scores and lung function parameters were significantly improved by ICS treatment. The mean IL-4 concentration in the EBC was decreased gradually, from 1.92 ± 0.56 pmol/L before treatment to 1.60 ± 0.36 pmolJL after 8 weeks of treatment （P 〈 0.05） and 1.54 ± 0.81 pmol/L after 12 weeks of treatment （P 〈 0.01）. However, the IL-6 concentration was not significantly decreased. The change in the IL-4 concentration was correlated with improvements in mean FEVt, PEF and FEFso values （correlation coefficients -0.468, -0.478, and -0.426, respectively）. Conclusions： The concentration of IL-4 in the EBC of asthmatic patients decreased gradually with ICS treatment. Measurement of IL-4 in EBC could be useful to monitor airway inflammation in asthmatics.

Toward point-of-care management of chronic respiratory conditions:Electrochemical sensing of nitrite content in exhaled breath condensate using reduced graphene oxide

We present a portable non-invasive approach for measuring indicators of inflammation and oxidative stress in the respiratory tract by quantifying a biomarker in exhaled breath condensate(EBC).We discuss the fabrication and characterization of a miniaturized electrochemical sensor for detecting nitrite content in EBC using reduced graphene oxide.The nitrite content in EBC has been demonstrated to be a promising biomarker of inflammation in the respiratory tract,particularly in asthma.We utilized the unique properties of reduced graphene oxide(rGO);specifically,the material is resilient to corrosion while exhibiting rapid electron transfer with electrolytes,thus allowing for highly sensitive electrochemical detection with minimal fouling.Our rGO sensor was housed in an electrochemical cell fabricated from polydimethyl siloxane(PDMS),which was necessary to analyze small EBC sample volumes.The sensor is capable of detecting nitrite at a low over-potential of 0.7 V with respect to an Ag/AgCl reference electrode.We characterized the performance of the sensors using standard nitrite/buffer solutions,nitrite spiked into EBC,and clinical EBC samples.The sensor demonstrated a sensitivity of 0.21μAμM^(−1) cm^(−2) in the range of 20–100μM and of 0.1μAμM^(−1) cm^(−2) in the range of 100–1000μM nitrite concentration and exhibited a low detection limit of 830 nM in the EBC matrix.To benchmark our platform,we tested our sensors using seven pre-characterized clinical EBC samples with concentrations ranging between 0.14 and 6.5μM.This enzyme-free and label-free method of detecting biomarkers in EBC can pave the way for the development of portable breath analyzers for diagnosing and managing changes in respiratory inflammation and disease.

Living near a Major Road in Beijing： Association with Lower Lung Function, Airway Acidification, and Chronic Cough

Background： The effects of near-road pollution on lung function in China have not been well studied. We aimed to investigate the effects of long-term exposure to traffic-related air pollution on lung function, airway inflammation, and respiratory symptoms. Methods： We enrolled 1003 residents aged 57.96 ± 8.99 years living in the Shichahai Community in Beijing. Distances between home addresses and the nearest major roads were measured to calculate home-road distance. We used the distance categories 1, 2, and 3, representing 〈100 m, 100-200 m, and 〉200 m, respectively, as the dose indicator for traffic-related air pollution exposure. Lung function, exhaled breath condensate （EBC） pH, and interleukin 6 levels were measured. As a follow-up, 398 participants had a second lung function assessment about 3 years later, and lung function decline was also examined as an outcome. We used regression analysis to assess the impacts of home-road distance on lung function and respiratory symptoms. As the EBC biomarker data were not normally distributed, we performed correlation analysis between home-road distance categories and EBC biomarkers. Results： Participants living a shorter distance from major roads had lower percentage of predicted value of forced expiratory volume in 1 s （FEV1% -1.54, 95% confidence interval [CI]： -0.20 to -2.89）. The odds ratio for chronic cough was 2.54 （95% CI： 1.57-4.10） for category 1 and 1.97 （95% CI： 1.16-3.37） for category 2, compared with category 3. EBC pH was positively correlated with road distance （rank correlation coefficient of Spearman [rs] = 0.176, P 〈 0.001 ）. Conclusions： Long-term exposure to traffic-related air pollution in people who live near major roads in Beijing is associated with lower lung function, airway acidification, and a higher prevalence of chronic cough. EBC pH is a potential useful biomarker for evaluating air pollution exposure.