Perceptions of Noninvasive Ventilation During Exercise in Noninvasive Ventilation-Naïve Patients With COPD.

BACKGROUND: The perceptions of using noninvasive ventilation (NIV) during exercise in patients with COPD who are naïve to NIV is unknown. The present study aimed to examine the perceptions of using NIV during exercise in people with COPD and to determine the relationship between patient perceptions with both baseline patient characteristics and exercise outcomes. METHODS: During a trial examining the effect of NIV during exercise on dynamic hyperinflation in people with COPD who were naïve to NIV, participants completed a 5-point Likert scale questionnaire (scored strongly disagree -2 to strongly agree +2) before and after using NIV during exercise and a semi-structured interview after using NIV during exercise. RESULTS: Eighteen participants, mean age (SD) 69 (7) y, FEV1/FVC 0.44 (0.08), FEV1 39 (7)% predicted, completed the study. Prior to exercise with NIV, participants were neutral about NIV, (mean [SD]) (0.67[0.84]). After exercise with NIV, participants felt that NIV made breathing easier (1.00 [0.77]) and that it helped exercise (1.06 [0.64]). There were moderate correlations between feeling that NIV was comfortable or effective and a change in exercise endurance time (ρ = - 0.588, P = .02), isotime inspiratory capacity (ρ = 0.488, P = .03), and measures of resting hyperinflation (ρ = 0.603, \P = .02). Interviews revealed that despite feeling comfortable using NIV during exercise, NIV might be too complicated for patients to manage outside a supervised environment. CONCLUSIONS: Individuals with COPD, naïve to NIV, and using NIV during exercise for the first time reported a positive effect of NIV on breathlessness and exercise performance. Participants' perceived benefit of NIV correlated moderately with increased endurance time and resting hyperinflation and with a reduction in dynamic hyperinflation during exercise, suggesting that patient reports could also aid selection of those who will benefit from NIV during exercise.

Outpatient Pulmonary Rehabilitation in Patients with Long COVID Improves Exercise Capacity, Functional Status, Dyspnea, Fatigue, and Quality of Life.

BACKGROUND: COVID-19 survivors face the risk of long-term sequelae including fatigue, breathlessness, and functional limitations. Pulmonary rehabilitation has been recommended, although formal studies quantifying the effect of rehabilitation in COVID-19 patients are lacking. METHODS: We conducted a prospective observational cohort study including consecutive patients admitted to an outpatient pulmonary rehabilitation center due to persistent symptoms after COVID-19. The primary endpoint was change in 6-min walk distance (6MWD) after undergoing a 6-week interdisciplinary individualized pulmonary rehabilitation program. Secondary endpoints included change in the post-COVID-19 functional status (PCFS) scale, Borg dyspnea scale, Fatigue Assessment Scale, and quality of life. Further, changes in pulmonary function tests were explored. RESULTS: Of 64 patients undergoing rehabilitation, 58 patients (mean age 47 years, 43% women, 38% severe/critical COVID-19) were included in the per-protocol-analysis. At baseline (i.e., in mean 4.4 months after infection onset), mean 6MWD was 584.1 m (±95.0), and functional impairment was graded in median at 2 (IQR, 2-3) on the PCFS. On average, patients improved their 6MWD by 62.9 m (±48.2, p < 0.001) and reported an improvement of 1 grade on the PCFS scale. Accordingly, we observed significant improvements across secondary endpoints including presence of dyspnea (p < 0.001), fatigue (p < 0.001), and quality of life (p < 0.001). Also, pulmonary function parameters (forced expiratory volume in 1 s, lung diffusion capacity, inspiratory muscle pressure) significantly increased during rehabilitation. CONCLUSION: In patients with long COVID, exercise capacity, functional status, dyspnea, fatigue, and quality of life improved after 6 weeks of personalized interdisciplinary pulmonary rehabilitation. Future studies are needed to establish the optimal protocol, duration, and long-term benefits as well as cost-effectiveness of rehabilitation.

Relationship between body composition, exercise capacity and health-related quality of life in idiopathic pulmonary fibrosis.

INTRODUCTION: Bioelectrical impedance analysis (BIA) can be used to estimate Fat-Free Mass Index (FFMI). However, the use of directly measured BIA variables, such as phase angle (PhA), has gained attention. The frequency of low FFMI and PhA and its associations with exercise capacity and health-related quality of life (HRQL) in patients with idiopathic pulmonary fibrosis (IPF) have been scarcely studied. OBJECTIVES: To investigate the frequency of low FFMI and PhA and their associations with exercise capacity and HRQL in patients with IPF. METHODS: Patients underwent assessment of lung function, body composition, exercise capacity by the 6 min walk distance (6MWD), and HRQL by the Medical Outcomes Study Short-Form 36-item Questionnaire (SF-36). Patients were classified as presenting normal or low PhA or FFMI, accordingly to the 10th percentiles of age-sex-body mass index (BMI)-specific reference values. RESULTS: 98 patients (84 males, age: 68±8 years, forced vital capacity: 64%±18%predicted) were included. 24 patients presented low PhA. They were characterised by worse lung function, exercise capacity and HRQL compared with patients with normal PhA. 10 patients presented low FFMI, but despite differences in body composition, no differences were found between these patients and patients with normal FFMI. In a single regression analysis, age, lung function and body composition variables (except FFMI) were related to 6MWD and SF-36 Physical Summary Score (R²=0.06-0.36, p<0.05). None of the variables were related to SF-36 Mental Summary Score. CONCLUSION: One-fourth of the patients with IPF with normal to obese BMI present abnormally low PhA. Patients classified as low PhA presented worse lung function, exercise capacity and HRQL.

Pulmonary rehabilitation in long COVID: more than just natural recovery!?

In the light of missing randomised controlled trials, some arguments suggest that pulmonary rehabilitation has beneficial effects beyond natural recovery https://bit.ly/3ze2xvw.

Bilevel Noninvasive Ventilation During Exercise Reduces Dynamic Hyperinflation and Improves Cycle Endurance Time in Severe to Very Severe COPD.

BACKGROUND: During exercise, dynamic hyperinflation (DH), measured by a reduction in inspiratory capacity (IC), increases exertional dyspnea and reduces functional capacity in many patients with severe COPD. Although noninvasive ventilation (NIV) during exercise can improve exercise duration, the effect on DH is unclear. RESEARCH QUESTIONS: In people with COPD, resting hyperinflation, and evidence of DH during exercise, does bilevel NIV during exercise reduce DH and increase endurance time compared with exercise with no NIV, and does NIV with an individually titrated expiratory positive airway pressure (T-EPAP) reduce DH and increase exercise endurance time more than NIV with standardized EPAP (S-EPAP) of 5 cm H2O? STUDY DESIGN AND METHODS: A randomized crossover trial in which investigators and participants were blinded between NIV interventions was performed. Participants (N = 19; FEV1 of 1.02 ± 0.24 L (39% ± 6% predicted) completed three constant work rate endurance cycle tests in random order-no NIV, NIV with S-EPAP, and NIV with T-EPAP-during exercise. Primary outcomes were isotime IC and exercise endurance time. Outcome measures from each intervention were compared at isotime and at end exercise by using a linear mixed-model analysis. RESULTS: Compared with no NIV, isotime IC and endurance time were greater with both NIV with S-EPAP (mean difference: 95% CI, 0.19 L [0.10-0.28]; 95% CI, 153 s [24-280], respectively) and T-EPAP (95% CI, 0.22 L [0.13-0.32]; 95% CI, 145 s [28-259], respectively). There was no difference between NIV with S-EPAP and NIV with T-EPAP. INTERPRETATION: In people with COPD and DH during exercise, NIV during exercise reduced DH and increased cycle endurance time. An S-EPAP of 5 cm H2O was adequate to obtain these benefits. TRIAL REGISTRY: Australian New Zealand Clinical Trials Registry; No.: ACTRN12613000804785; URL: http://www.anzctr.org.au.

Influence of an Acute Exacerbation During Pulmonary Rehabilitation in Patients With Chronic Obstructive Pulmonary Disease Awaiting Lung Transplantation.

PURPOSE: Pulmonary rehabilitation (PR) has been shown to be an effective intervention in patients with very severe chronic obstructive pulmonary disease (COPD) awaiting lung transplantation (LTx). The objective of this study was to characterize the prevalence of acute exacerbations (AEs) during PR and their impact on the outcomes of pre-LTx PR. METHODS: In this retrospective analysis, 559 patients with COPD awaiting LTx who were referred to a 4-wk inpatient PR program were evaluated. A total of 114 patients (20%) acquired an AE during PR and continued in an adapted fashion. Pulmonary function testing, 6-min walk test (6MWT), and a health-related quality-of-life questionnaire (SF-36) were administered on admission and on discharge of PR. RESULTS: Following PR, both groups, patients with and without AE, increased their 6MWT significantly (P < .001) to a clinically relevant amount (58 ± 72 and 52 ± 64 m, respectively). The sum scores of the SF-36 also improved significantly without any between-group differences. No observed changes were different between the two groups. No relevant predictors for PR outcomes could be detected by logistic regression. CONCLUSIONS: Our data show that patients with end-stage COPD listed for LTx can achieve clinically relevant improvements in functional exercise capacity and quality of life even if they develop an AE during PR.

Benefits of pulmonary rehabilitation in COVID-19: a prospective observational cohort study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) can result in a large variety of chronic health issues such as impaired lung function, reduced exercise performance and diminished quality of life. Our study aimed to investigate the efficacy, feasibility and safety of pulmonary rehabilitation in COVID-19 patients and to compare outcomes between patients with a mild/moderate and a severe/critical course of the disease. METHODS: Patients in the post-acute phase of a mild to critical course of COVID-19 admitted to a comprehensive 3-week inpatient pulmonary rehabilitation programme were included in this prospective, observational cohort study. Several measures of exercise performance (6-min walk distance (6MWD)), lung function (forced vital capacity (FVC)) and quality of life (36-question short-form health survey (SF-36)) were assessed before and after pulmonary rehabilitation. RESULTS: 50 patients were included in the study (24 with mild/moderate and 26 with severe/critical COVID-19). On admission, patients had a reduced 6MWD (mild: median 509 m, interquartile range (IQR) 426-539 m; severe: 344 m, 244-392 m), an impaired FVC (mild: 80%, 59-91%; severe: 75%, 60-91%) and a low SF-36 mental health score (mild: 49 points, 37-54 points; severe: 39 points, 30-53 points). Patients attended a median (IQR) 100% (94-100%) of all provided pulmonary rehabilitation sessions. At discharge, patients in both subgroups improved in 6MWD (mild/moderate: +48 m, 35-113 m; severe/critical: +124 m, 75-145 m; both p<0.001), FVC (mild/moderate: +7.7%, 1.0-17.8%, p=0.002; severe/critical: +11.3%, 1.0-16.9%, p<0.001) and SF-36 mental component (mild/moderate: +5.6 points, 1.4-9.2 points, p=0.071; severe/critical: +14.4 points, -0.6-24.5, p<0.001). No adverse event was observed. CONCLUSION: Our study shows that pulmonary rehabilitation is a feasible, safe and effective therapeutic option in COVID-19 patients independent of disease severity.

Whole-body vibration training versus conventional balance training in patients with severe COPD-a randomized, controlled trial.

BACKGROUND: Whole-body vibration training (WBV) performed on a vibration platform can significantly improve physical performance in patients with chronic obstructive pulmonary disease. It has been suggested that an important mechanism of this improvement is based on an improvement in balance. Therefore, the aim of this study was to investigate the effects of WBV compared to conventional balance training. METHODS: 48 patients with severe COPD (FEV1: 37 ± 7%predicted) and low exercise performance (6 min walk distance (6MWD): 55 ± 10%predicted) were included in this randomized controlled trial during a 3 week inpatient pulmonary rehabilitation. All patients completed a standardized endurance and strength training program. Additionally, patients performed 4 different balance exercises 3x/week for 2 sets of 1 min each, either on a vibration platform (Galileo) at varying frequencies (5-26 Hz) (WBV) or on a conventional balance board (BAL). The primary outcome parameter was the change in balance performance during a semi tandem stance with closed eyes assessed on a force measurement platform. Muscular power during a countermovement jump, the 6MWD, and 4 m gait speed test (4MGST) were secondary outcomes. Non-parametric tests were used for statistical analyses. RESULTS: Static balance performance improved significantly more (p = 0.032) in favor of WBV (path length during semi-tandem stand: - 168 ± 231 mm vs. + 1 ± 234 mm). Muscular power also increased significantly more (p = 0.001) in the WBV group (+ 2.3 ± 2.5 W/kg vs. - 0.1 ± 2.0 W/kg). 6MWD improved to a similar extent in both groups (WBV: 48 ± 46 m, p < 0.001 vs. BAL: 38 ± 32 m; p < 0.001) whereas the 4MGST increased significantly only in the WBV-group (0.08 ± 0.14 m/s2, p = 0.018 vs. 0.01 ± 0.11 m/s2, p = 0.71). CONCLUSIONS: WBV can improve balance performance and muscular power significantly more compared to conventional balance training. TRIAL REGISTRATION: Clinical-Trials registration number: NCT03157986; date of registration: May 17, 2017. https://clinicaltrials.gov/ct2/results?cond=&term=NCT03157986&cntry=&state=&city=&dist = .

Constitutive immune activity promotes JNK- and FoxO-dependent remodeling of Drosophila airways.

Extensive remodeling of the airways is a major characteristic of chronic inflammatory lung diseases such as asthma or chronic obstructive pulmonary disease (COPD). To elucidate the importance of a deregulated immune response in the airways for remodeling processes, we established a matching Drosophila model. Here, triggering the Imd (immune deficiency) pathway in tracheal cells induced organ-wide remodeling. This structural remodeling comprises disorganization of epithelial structures and comprehensive epithelial thickening. We show that these structural changes do not depend on the Imd pathway's canonical branch terminating on nuclear factor κB (NF-κB) activation. Instead, activation of a different segment of the Imd pathway that branches off downstream of Tak1 and comprises activation of c-Jun N-terminal kinase (JNK) and forkhead transcription factor of the O subgroup (FoxO) signaling is necessary and sufficient to mediate the observed structural changes of the airways. Our findings imply that targeting JNK and FoxO signaling in the airways could be a promising strategy to interfere with disease-associated airway remodeling processes.

Protocol for an observational study to identify potential predictors of an acute exacerbation in patients with chronic obstructive pulmonary disease (the PACE Study).

INTRODUCTION: Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are the most critical events for patients with COPD that have a negative impact on patients' quality of life, accelerate disease progression, and can result in hospital admissions and death. Although there is no distinct definition or detailed knowledge about AECOPD, it is commonly used as primary outcome in clinical studies. Furthermore, it may be difficult in clinical practice to differentiate the worsening of symptoms due to an AECOPD or to the development of heart failure. Therefore, it is of major clinical importance to investigate the underlying pathophysiology, and if possible, predictors of an AECOPD and thus to identify patients who are at high risk for developing an acute exacerbation. METHODS AND ANALYSIS: In total, 355 patients with COPD will be included prospectively to this study during a 3-week inpatient pulmonary rehabilitation programme at the Schoen Klinik Berchtesgadener Land, Schoenau am Koenigssee (Germany). All patients will be closely monitored from admission to discharge. Lung function, exercise tests, clinical parameters, quality of life, physical activity and symptoms will be recorded, and blood samples and exhaled air will be collected. If a patient develops an AECOPD, there will be additional comprehensive diagnostic assessments to differentiate between cardiac, pulmonary or cardiopulmonary causes of worsening. Follow-up measures will be performed at 6, 12 and 24 months.Exploratory data analyses methods will be used for the primary research question (screening and identification of possible factors to predict an AECOPD). Regression analyses and a generalised linear model with a binomial outcome (AECOPD) will be applied to test if predictors are significant. ETHICS AND DISSEMINATION: This study has been approved by the Ethical Committee of the Philipps University Marburg, Germany (No. 61/19). The results will be presented in conferences and published in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: NCT04140097.

Short-Term Effects of Comprehensive Pulmonary Rehabilitation and its Maintenance in Patients with Idiopathic Pulmonary Fibrosis: A Randomized Controlled Trial.

The recommendation for pulmonary rehabilitation (PR) in idiopathic pulmonary fibrosis (IPF) is weak with low-quality evidence. Therefore, the aim of this study is to investigate short-term PR effects and their maintenance after a 3-month follow-up. Fifty-four IPF patients were randomized into a group receiving a 3-week comprehensive, inpatient PR (n = 34, FVC: 74 ± 19% pred.) or usual care (UC) (n = 17, FVC: 72 ± 20%pred.). Outcomes were measured at baseline (T1), after intervention (T2), and 3 months after T2 (T3). A 6-min walk distance (6MWD) was used as the primary outcome and chronic respiratory disease questionnaire (CRQ) scores as the secondary outcome. Change in 6MWD from T1 to T2 (Δ = 61 m, 95% CI (18.5-102.4), p = 0.006) but not from T1 to T3 (∆ = 26 m, 95% CI (8.0-61.5), p = 0.16) differed significantly between groups. Higher baseline FVC and higher anxiety symptoms were significant predictors of better short-term 6MWD improvements. For the change in CRQ total score, a significant between-group difference from T1 to T2 (∆ = 3.0 pts, 95% CI (0.7-5.3), p = 0.01) and from T1 to T3 (∆ = 3.5 pts, 95% CI (1.5-5.4), p = 0.001) was found in favour of the PR group. To conclude, in addition to the short-term benefits, inpatient PR is effective at inducing medium-term quality of life improvements in IPF. PR in the early stages of the disease seems to provoke the best benefits.

[Easy come, easy go? Current strategies for maintaining the effects of pulmonary rehabilitation in COPD patients]. / Wie gewonnen, so zerronnen?

Easy come, easy go? Current strategies for maintaining the effects of pulmonary rehabilitation in COPD patients Abstract. Pulmonary rehabilitation (PR) is a comprehensive treatment method in the non-drug management of chronic respiratory diseases. Most evident data exists for COPD patients. However, the effect of PR is no longer detectable after 6 to 12 months, unless the patient participates in a kind of maintenance program following PR. But the contents of such a maintenance program are still unclear in terms of duration, location, methods and intensity. They are still subject of current research. Therefore concrete recommendations are still missing and further studies are necessary. This review aims to give an overview of the existing results in this field.

Low-Volume Whole-Body Vibration Training Improves Exercise Capacity in Subjects With Mild to Severe COPD.

BACKGROUND: The objective of this study was to investigate the benefits of a low-volume out-patient whole-body vibration training (WBVT) program on exercise capacity in comparison with a calisthenics training program in subjects with COPD. METHODS: In this single-center randomized controlled trial, 29 subjects with mild to severe COPD were randomized to WBVT or to calisthenics training, including relaxation and breathing retraining in combination with calisthenics exercises. Both groups equally exercised for a duration of 3 months with 2 sessions of 30 min/week. Outcome parameters were 6-min walk distance (6MWD, primary outcome), 5-repetition sit-to-stand test, leg press peak force, Berg balance scale, St George Respiratory Questionnaire, and COPD assessment test. RESULTS: Twenty-seven subjects completed the study (WBVT, n = 14; calisthenics training program, n = 13). Baseline characteristics between groups were comparable. Subjects in the WBVT group significantly improved median (interquartile range) 6MWD (+105 [45.5-133.5] m, P = .001), sit-to-stand test (-2.3 [-3.1 to -1.3] s, P = .001), peak force (28.7 [16.7-33.3] kg, P = .001), and Berg balance scale (1.5 [0.0-4.0] points, P = .055). Changes in 6MWD, sit-to-stand test, and leg press peak force were also found to be significantly different between groups in favor of the WBVT group. Only the between-group difference of the COPD assessment test score was in favor of the calisthenics training group (P = .02). CONCLUSIONS: A low-volume WBVT program resulted in significantly and clinically relevant larger improvements in exercise capacity compared with calisthenics exercises in subjects with mild to severe COPD. (ClinicalTrials.gov registration DRKS9706.).

New concepts in asthma: clinical phenotypes and pathophysiological mechanisms.

Asthma is among the most common chronic inflammatory diseases worldwide. Recent evidence indicates that the pathogenesis shows a high degree of heterogeneity. Patient subsets have been identified that exhibit different cellular and molecular patterns of dysregulation. A prominent example is eosinophilic Th2-driven asthma. These unique and molecular patterns are termed endotypes. Characterization of endotypes has broad implications for therapeutic interventions. Although ∼80% of asthmatic patients respond well to standard anti-inflammatory therapies, the remaining subset particularly consisting of severe patients requires a more specialized endotype-specific approach. This interrelationship between clinical phenotypes, molecular endotypes and endotype-specific therapies is the focus of this review.

Hydrogen peroxide in exhaled air: a source of error, a paradox and its resolution.

The concentration of hydrogen peroxide (H2O2) in exhaled air has been reported to be elevated in asthma and chronic obstructive pulmonary disease (COPD), but results are inconsistent and difficult to reproduce. As H2O2 occurs in ambient air, we examined its association with exhaled H2O2 in human subjects. Exhaled breath condensate (EBC) of 12 COPD patients and nine healthy control subjects was collected either with an inhalation filter (efficiency 81%) or without. Ambient air condensate (AAC) was collected in parallel and samples were analysed for H2O2. Additionally, ambient H2O2 was recorded by an atmospheric measuring device (online fluorometric measurement). H2O2 concentration in AAC was significantly higher (p<0.001) than in EBC. AAC variations were concordant with the data from the atmospheric measuring instrument. In both subjects' groups, the inhalation filter reduced H2O2 values (p<0.01). Despite generally low levels in exhaled air, analysis by a mathematical model revealed a contribution from endogenous H2O2 production. The low H2O2 levels in exhaled air are explained by the reconditioning of H2O2-containing inhaled air in the airways. Inhaled H2O2 may be one factor in the heterogeneity and limited reproducibility of study results. A valid determination of endogenous H2O2 production requires inhalation filters.

Emphysema- and airway-dominant COPD phenotypes defined by standardised quantitative computed tomography.

EvA (Emphysema versus Airway disease) is a multicentre project to study mechanisms and identify biomarkers of emphysema and airway disease in chronic obstructive pulmonary disease (COPD). The objective of this study was to delineate objectively imaging-based emphysema-dominant and airway disease-dominant phenotypes using quantitative computed tomography (QCT) indices, standardised with a novel phantom-based approach.441 subjects with COPD (Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 1-3) were assessed in terms of clinical and physiological measurements, laboratory testing and standardised QCT indices of emphysema and airway wall geometry.QCT indices were influenced by scanner non-conformity, but standardisation significantly reduced variability (p<0.001) and led to more robust phenotypes. Four imaging-derived phenotypes were identified, reflecting "emphysema-dominant", "airway disease-dominant", "mixed" disease and "mild" disease. The emphysema-dominant group had significantly higher lung volumes, lower gas transfer coefficient, lower oxygen (PO2 ) and carbon dioxide (PCO2 ) tensions, higher haemoglobin and higher blood leukocyte numbers than the airway disease-dominant group.The utility of QCT for phenotyping in the setting of an international multicentre study is improved by standardisation. QCT indices of emphysema and airway disease can delineate within a population of patients with COPD, phenotypic groups that have typical clinical features known to be associated with emphysema-dominant and airway-dominant disease.

Airflow limitation in COPD is associated with increased left ventricular wall stress in coincident heart failure.

BACKGROUND: COPD and heart failure occur with a considerable coincidence. Beside well-known mechanisms of increased right heart load in COPD, dedicated changes of the left ventricle (LV) are ill-defined and the question remains, whether specific interactions exist beyond common shared risk factors. METHODS: LV wall stress was calculated based on cardiac magnetic resonance imaging in 28 patients with COPD (GOLD I to III) and coexistent heart failure (LVEF 42 ± 19%) due to non-ischaemic and ischaemic cardiomyopathy. RESULTS: LV enddiastolic (p = 0.048) and endsystolic wall stress (p = 0.034) increased from GOLD stage I to III. Reduced FEV1 was correlated with increased enddiastolic (p = 0.0210) and endsystolic LV volume (p = 0.0413) and with increased enddiastolic (p = 0.0161) and endsystolic LV wall stress (p = 0.0315), respectively. Increased wall stress was associated with a decreased FEV1/FVC ratio. CONCLUSIONS: The severity of airflow limitation in COPD was correlated with increased LV wall stress. It is suggested that respiration in pulmonary obstruction is associated with an increased negative intrathoracic pressure when compared with normal lung function, which is transmitted to the heart and increases the transmural pressure gradient and thereby distending forces on the heart. Increased ventricular wall stress is known to be associated with a broad variety of unfavourable consequences, which should be taken into account to contribute to a worse prognosis in COPD.

Ambient temperature impacts on pH of exhaled breath condensate.

BACKGROUND AND OBJECTIVE: Analysis of exhaled breath condensate (EBC) pH is a non-invasive method to study airway inflammation. Low pH is correlated with inflammatory diseases like asthma and COPD. The aim of this study was to assess the influence of measurement temperature on pH values of EBC. METHODS: EBC was collected using the RTube in 10 healthy non-smoking controls, 10 smokers before and after cigarette smoking, 10 stable COPD patients and 10 patients with exacerbated COPD. pH was determined directly after degassing at temperatures of 23 degrees C and 37 degrees C. RESULTS: When comparing all groups pH was significantly (P = 0.0002) higher (mean +/- SD 7.88 +/- 0.92) at 37 degrees C as compared with 23 degrees C (7.44 +/- 0.90). Specifically, at 23 degrees C pH was significantly lower in the group of exacerbated COPD (6.78 +/- 1.27) and healthy non-smoking controls (8.04 +/- 0.39). In contrast, subgroup analysis of values assessed at 37 degrees C did not display significant differences. CONCLUSIONS: Our data indicate a considerable influence of temperature on pH values in EBC. Thus the temperature at which pH measurements in EBC studies are performed should be declared.

Antimicrobial peptides: current status and therapeutic potential.

Antimicrobial peptides (AMPs) are effector molecules of the innate immune system. A variety of AMPs have been isolated from species of all kingdoms and are classified based on their structure and amino acid motifs. AMPs have a broad antimicrobial spectrum and lyse microbial cells by interaction with biomembranes. Besides their direct antimicrobial function, they have multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cell proliferation, immune induction, wound healing, cytokine release, chemotaxis and protease-antiprotease balance. AMPs qualify as prototypes of innovative drugs that may be used as antimicrobials, anti-lipopolysaccharide drugs or modifiers of inflammation. Several strategies have been followed to identify lead candidates for drug development, to modify the peptides' structures, and to produce sufficient amounts for pre-clinical and clinical studies. This review summarises the current knowledge about the basic and applied biology of AMPs.