Reconditioning of an injured lung graft with intrabronchial surfactant instillation in an ex vivo lung perfusion system followed by transplantation.

BACKGROUND: We tested whether an injured lung graft from category-3 donation after cardiac death donor could be reconditioned with an ex vivo lung perfusion (EVLP) system by intrabronchial diluted surfactant lavage before transplantation. METHODS: In a pig model, cardiac arrest was induced by deconnecting from the ventilator. Left lung injury was done by intrabronchial instillation of 1 mL/kg pepsin + HCl. After retrieval, the heart-lung block was stored at 4°C for 2 h. In the treated group, transplantation was performed after reconditioning with intrabronchial diluted surfactant lavage in EVLP system. RESULTS: During EVLP, surfactant group showed better oxygenation and lower pulmonary vascular resistance. After transplantation, better oxygenation, lower mean pulmonary artery pressure, and lower lung edema were observed in surfactant group. Lower blood IL-1 beta and IL-6 cytokine levels were measured in the surfactant group. In bronchoalveolar lavage, the percentage of neutrophils, IL-1 beta and IL-6 cytokine levels, amount of protein, and neutrophil infiltration in the lung tissue at the end of the experiment were significantly lower in the surfactant group. CONCLUSIONS: Our data demonstrate the feasibility of reconditioning and transplantation of an acutely damaged lung graft due to aspiration from a category-3 DCD donor. Implementation of an EVLP system is an efficacious tool to recondition and assess a questionable graft before transplantation.

Online breath analysis with SESI/HRMS for metabolic signatures in children with allergic asthma.

Introduction: There is a need to improve the diagnosis and management of pediatric asthma. Breath analysis aims to address this by non-invasively assessing altered metabolism and disease-associated processes. Our goal was to identify exhaled metabolic signatures that distinguish children with allergic asthma from healthy controls using secondary electrospray ionization high-resolution mass spectrometry (SESI/HRMS) in a cross-sectional observational study. Methods: Breath analysis was performed with SESI/HRMS. Significant differentially expressed mass-to-charge features in breath were extracted using the empirical Bayes moderated t-statistics test. Corresponding molecules were putatively annotated by tandem mass spectrometry database matching and pathway analysis. Results: 48 allergic asthmatics and 56 healthy controls were included in the study. Among 375 significant mass-to-charge features, 134 were putatively identified. Many of these could be grouped to metabolites of common pathways or chemical families. We found several pathways that are well-represented by the significant metabolites, for example, lysine degradation elevated and two arginine pathways downregulated in the asthmatic group. Assessing the ability of breath profiles to classify samples as asthmatic or healthy with supervised machine learning in a 10 times repeated 10-fold cross-validation revealed an area under the receiver operating characteristic curve of 0.83. Discussion: For the first time, a large number of breath-derived metabolites that discriminate children with allergic asthma from healthy controls were identified by online breath analysis. Many are linked to well-described metabolic pathways and chemical families involved in pathophysiological processes of asthma. Furthermore, a subset of these volatile organic compounds showed high potential for clinical diagnostic applications.

Data accuracy, consistency and completeness of the national Swiss cystic fibrosis patient registry: Lessons from an ECFSPR data quality project.

BACKGROUND: Good data quality is essential when rare disease registries are used as a data source for pharmacovigilance studies. This study investigated data quality of the Swiss cystic fibrosis (CF) registry in the frame of a European Cystic Fibrosis Society Patient Registry (ECFSPR) project aiming to implement measures to increase data reliability for registry-based research. METHODS: All 20 pediatric and adult Swiss CF centers participated in a data quality audit between 2018 and 2020, and in a re-audit in 2022. Accuracy, consistency and completeness of variables and definitions were evaluated, and missing source data and informed consents (ICs) were assessed. RESULTS: The first audit included 601 out of 997 Swiss people with CF (60.3 %). Data quality, as defined by data correctness ≥95 %, was high for most of the variables. Inconsistencies of specific variables were observed because of an incorrect application of the variable definition. The proportion of missing data was low with <5 % for almost all variables. A considerable number of missing source data occurred for CFTR variants. Availability of ICs varied largely between centers (10 centers had >5 % of missing documents). After providing feedback to the centers, availability of genetic source data and ICs improved. CONCLUSIONS: Data audits demonstrated an overall good data quality in the Swiss CF registry. Specific measures such as support of the participating sites, training of data managers and centralized data collection should be implemented in rare disease registries to optimize data quality and provide robust data for registry-based scientific research.

Surfactant alterations following donation after cardiac death donor lungs.

The use of lungs from donation after cardiac death (DCD) donors is one of the strategies to increase the donor pool. The aim of this study was to assess the surfactant alterations in DCD donor lungs. Pigs were sacrificed and left untouched for 1 (DCD1), 2 (DCD2) and 3 (DCD3) h. Lungs were then topically cooled with saline for 1, 2 or 3 h to reach a total ischemic time of 4 h. Heart-beating donors (HBD) served as control group. Bronchoalveolar lavage (BAL) samples were assessed for protein levels and surfactant function. Left lungs were prepared for ex-vivo evaluation. Pulmonary vascular resistance (PVR), oxygenation, airway pressure (AWP) and wet-to-dry weight ratio were significantly different between HBD and DCD3 groups (P < 0.05). BAL protein levels were statistically higher in DCD3 compared with HBD group (P < 0.05). Surface tension and surface tension measured at minimal bubble diameter (adsorption) were lower in HBD compared with DCD groups (P < 0.05). Adsorption was also lower in DCD1 compared with DCD2 (P < 0.05). Adsorption and surface tension were correlated with oxygenation and AWP (P < 0.05). This study has shown that lung function deteriorates with increasing warm ischemic time intervals. BAL protein, surface tension, adsorption, peak AWP and PVR increase significantly after 2 h of warm ischemia together with a significant reduction of the ratio PaO(2)/FiO(2).

Volatile organic compound breath signatures of children with cystic fibrosis by real-time SESI-HRMS.

Early pulmonary infection and inflammation result in irreversible lung damage and are major contributors to cystic fibrosis (CF)-related morbidity. An easy to apply and noninvasive assessment for the timely detection of disease-associated complications would be of high value. We aimed to detect volatile organic compound (VOC) breath signatures of children with CF by real-time secondary electrospray ionisation high-resolution mass spectrometry (SESI-HRMS). A total of 101 children, aged 4-18 years (CF=52; healthy controls=49) and comparable for sex, body mass index and lung function were included in this prospective cross-sectional study. Exhaled air was analysed by a SESI-source linked to a high-resolution time-of-flight mass spectrometer. Mass spectra ranging from m/z 50 to 500 were recorded. Out of 3468 m/z features, 171 were significantly different in children with CF (false discovery rate adjusted p-value of 0.05). The predictive ability (CF versus healthy) was assessed by using a support-vector machine classifier and showed an average accuracy (repeated cross-validation) of 72.1% (sensitivity of 77.2% and specificity of 67.7%). This is the first study to assess entire breath profiles of children with SESI-HRMS and to extract sets of VOCs that are associated with CF. We have detected a large set of exhaled molecules that are potentially related to CF, indicating that the molecular breath of children with CF is diverse and informative.

Reported Exercise-Related Respiratory Symptoms and Exercise-Induced Bronchoconstriction in Asthmatic Children.

BACKGROUND: Unlimited physical activity is one of the key issues of asthma control and management. We investigated how reliable reported exercise-related respiratory symptoms (ERRS) are in predicting exercise-induced bronchoconstriction (EIB) in asthmatic children. METHODS: In this prospective study, 179 asthmatic children aged 7 - 15 years were asked for specific questions on respiratory symptoms related to exercise and allocated into two groups according to whether they complained about symptoms. Group I (n = 134) consisted of children answering "yes" to one or more of the questions and group II (n = 45) consisted of children answering "no" to all of the questions. RESULTS: Sixty-four of 179 children showed a positive exercise challenge test (ECT). There was no difference in the frequency of a positive test between children in group I (n = 48) and group II (n = 12) (P = 0.47). The sensitivity of a positive report for ERRS to predict a positive ECT was only 37%, with a specificity of 0.72. CONCLUSION: According to current guidelines, the report or lack of ERRS has direct consequences on treatment decisions. However, the history of ERRS did not predict EIB and one-third of asthmatic children without complaints of ERRS developed EIB during the ECT. This raises the question of the need for objective measures of bronchial hyperresponsiveness (BHR) in pediatric asthma management.

Melatonin attenuates posttransplant lung ischemia-reperfusion injury.

BACKGROUND: Melatonin, a pineal hormone, is a free radical scavenger and an antioxidant. The purpose of this study was to assess the protective effect of melatonin on posttransplant lung ischemia-reperfusion injury. METHODS: Rat single-lung transplantation was performed in two (n = 10) experimental groups after 18 hours of cold (4 degrees C) ischemia. Group I animals consisted of the ischemic control group. In group II, donor and recipient animals were treated with intraperitoneal injection of 10 mg/kg melatonin 10 minutes before harvest and reperfusion, respectively. After 2 hours of reperfusion, oxygenation, plasma, and bronchoalveolar lavage nitrite levels were measured. Lung tissue was assessed for thiobarbituric acid reactive substances and myeloperoxidase activity. Peak airway pressure was recorded throughout the reperfusion period. RESULTS: The melatonin-treated group showed significantly better oxygenation (321.8+/-33.8 mm Hg versus 86.1+/-17.4 mm Hg; p < 0.001), reduced lipid peroxidation (0.65+/-0.3 nmol/g versus 1.63+/-0.8 nmol/g; p = 0.032), and reduced myeloperoxidase activity (0.56+/-0.1 deltaOD x mg(-1) x min(-1) versus 1.01+/-0.2 deltaOD x mg(-1) x min(-1); p = 0.032). Bronchoalveolar lavage nitrite levels in the transplanted lungs were significantly lower in group II than in group I (0.34+/-0.06 micromol/L versus 1.65+/-0.6 micromol/L; p = 0.016). In group II significant reduction in peak airway pressure was noted compared with group I (p = 0.002). CONCLUSIONS: In this model, exogenously administered melatonin effectively protected lungs from reperfusion injury after prolonged ischemia.

Surfactant improves graft function after gastric acid-induced lung damage in lung transplantation.

BACKGROUND: The number of available donor lungs is still the limiting factor in lung transplantation. We have recently shown that diluted surfactant lavage during ex vivo lung evaluation improved the graft function after gastric acid aspiration. In the present study, we hypothesized that diluted surfactant administration would recondition and improve the graft function after acid aspiration-induced lung injury in a porcine model of pulmonary transplantation. METHODS: Left lung injury was induced by intrabronchial administration of 1 mL/kg betaine HCl and pepsin mixture. The animals were subsequently ventilated for 24 hours. After organ retrieval, the donor lungs were stored at 4°C for 4 hours. In the control group, left lung transplantation was performed without any surfactant treatment. In the surfactant group, the recipients received intratracheal diluted surfactant lavage just before reperfusion and ventilation. During 7 hours of reperfusion, the hemodynamic and respiratory variables were recorded on an hourly basis. RESULTS: Surfactant lavage resulted in lower mean pulmonary artery pressure, higher mixed venous oxygen saturation, and better oxygenation compared with the control group (p = 0.001). Bronchoalveolar lavage interleukin-6 level, protein, and neutrophil percentage at the end of the experiment were significantly higher in the control group compared with the surfactant group (p = 0.03). Minimal surface tension was significantly lower in the surfactant group compared with controls (p = 0.03). CONCLUSIONS: These results demonstrate that application of diluted surfactant before reperfusion can be used effectively to improve the graft function from donor lungs injured by gastric acid aspiration.

Exhaled nitric oxide decreases after positive food-allergen challenge.

BACKGROUND: Exhaled nitric oxide (FeNO) is a well described marker of airway inflammation in asthma and is also known to increase after chronic exposure to inhaled allergens. It is not known whether monitoring FeNO could be useful during food challenges to detect early or subclinical reactions. METHODS: Forty children aged 3 to 16 years undergoing an allergen-food challenge at two centres were prospectively recruited for this study. FeNO was assessed before and repeatedly after the food-challenge. RESULTS: Data were obtained from a total of 53 challenges (16 positive, 37 negative) and were compared between the two groups. Half of the patients with a positive food challenge exhibited clinical upper respiratory symptoms. The FeNO significantly decreased in 7 of 16 patients with a positive challenge test within 60 to 90 minutes after the first symptoms of an allergic reaction. CONCLUSION: Our results show a significant decrease in FeNO after a positive food challenge suggesting involvement of the lower airways despite absence of clinical and functional changes of lower airways. Prospective blinded studies are needed to confirm these results.

Prevention of primary graft dysfunction in lung transplantation by N-acetylcysteine after prolonged cold ischemia.

BACKGROUND: N-Acetylcysteine (NAC), a thiol-containing compound that has been used as an anti-oxidant, may also lead to an increased glutathione synthesis. This study assessed the protective effect of NAC on primary graft dysfunction after lung transplantation. METHODS: Porcine single left-lung transplantation was performed in 2 experimental groups after 24 hours of cold storage. Donor and recipient animals were treated with intravenous injection of 150 mg/kg NAC 60 minutes before harvest and reperfusion, followed by 12.5 mg/kg/hour continuous perfusion during the 8-hour observation period (NAC). Control animals did not receive any treatment. Hemodynamic and respiratory parameters were recorded throughout the observation period. Bronchoalveolar lavage (BAL) nitrite, neutrophil elastase (NE), protein accumulation, interleukin (IL)-8, nuclear factor-κB (p50 sub-unit), and reduced glutathione (GSH) in lung tissue and red blood were measured. RESULTS: During the observation period, the mean pulmonary artery pressure, oxygenation, airway pressure, and static lung compliance were significantly better in NAC animals compared with controls (p < 0.05). Extravascular lung water index was higher at points during the reperfusion in the control group. BAL protein, nitrite, NE, and IL-8 cytokine levels at the end of the experiment were significantly higher in the controls than in the NAC group (p < 0.05). Lung tissue reduced GSH levels were significantly higher in the NAC group than in the control group. Red blood cell GSH levels were always higher in the NAC group during the reperfusion period. Reverse transcription polymerase chain reaction for IL-8 messenger RNA was significantly higher in controls during the reperfusion period than in the NAC group (p = 0.001). The amount of lung tissue nuclear NF-κB (p50 sub-unit) was significantly higher in controls than in NAC pigs (p = 0.03). CONCLUSION: In this model, donor and recipient treatment with NAC effectively protected the lung from primary graft dysfunction after prolonged cold ischemia.

Ex vivo reconditioning of marginal donor lungs injured by acid aspiration.

BACKGROUND: Injured lungs due to gastric acid aspiration may be rejected for transplantation because of the possibility of early graft dysfunction. We hypothesized that diluted surfactant administration during ex vivo perfusion would recondition the lungs injured by acid aspiration and permit their use as suitable grafts for transplantation. METHODS: Using a pig model, lung injury was induced with 5-ml/kg administration of a betaine-HCl/pepsin mixture via a flexible bronchoscope. After injury, animals were randomly assigned to three study groups (n = 6/group): saline lavage during ex vivo perfusion (control); surfactant lavage ex vivo (SL-Exvivo); and surfactant lavage before harvest (SL-Pre); and a normal group (n = 4), with no lung injury. Cold storage time was 3 hours. A volume of 10 ml/kg (4 mg/ml, 40 mg/kg) surfactant (Curosurf) was used for lavage. Bronchoalveolar lavage (BAL) was performed before and after injury and at the end of the experiment. Protein and neutrophil percentage in BAL were assessed. Hemodynamic and aerodynamic parameters were measured every 30 minutes during a 2-hour observation period. RESULTS: An approximately 50% decrease in Pao(2) was observed in all animals after injury. Ex vivo surfactant lavage resulted in lower pulmonary vascular resistance, lower oxygenation index and higher Pao(2)/Fio(2) ratio compared with the control group (p = 0.001, p = 0.0001 and p = 0.0001, respectively, according to analysis of variance for repeated measures). Wet-to-dry weight ratio was lower in the SL-Exvivo group compared with the control group (p = 0.015). BAL neutrophil percent at the end of the experiment differed significantly between control and all other groups (p < 0.05). CONCLUSION: Diluted surfactant lavage during ex vivo perfusion improves graft function of lungs injured by gastric acid aspiration.

Impact of topical cooling solution and prediction of pulmonary graft viability from non-heart-beating donors.

BACKGROUND: Functional assessment of the potentially damaged graft from a non-heart-beating donor (NHBD) is mandatory for successful outcome after transplantation. We investigated the impact of the topical cooling solution on graft preservation and whether inflammatory markers in bronchoalveolar lavage (BAL) can predict pulmonary graft viability in a pig ex vivo lung perfusion model. METHODS: Pigs were euthanized and left untouched for 1 (SAL-1, PER-1) or 3 (SAL-3, PER-3) hours. Topical cooling was done with saline or low-potassium dextran solution (Perfadex) for 1 or 3 hours. In the heart-beating donor control group, the lungs were flushed, explanted and stored for 4 hours. BAL samples were taken from right lungs after explantation and assessed for nitrite, interleukin-8 (IL-8) and protein levels. Left lungs were prepared for ex vivo evaluation. Hemodynamic and oxygenation parameters were measured. RESULTS: Pulmonary vascular resistance (PVR), oxygenation index and Pao(2)/Fio(2) ratio differed significantly between the SAL-3 (42.2 +/- 6.0, 15.9 +/- 3.2 and 148 +/- 14.6 Wood units, respectively) and PER-3 (23.9 +/- 2.7, 6.4 +/- 0.8 and 221.7 +/- 15.06 Wood units, respectively) groups (p < 0.05). BAL IL-8 levels were higher in the SAL-3 group compared with the PER-3 group. BAL nitrite and protein levels were statistically higher in the SAL-3 group (0.98 +/- 0.17 micromol/liter, 728.3 +/- 75.7 microg/ml) than in the PER-3 (0.22 +/- 0.09 micromol/liter, 393.3 +/- 51.1 microg/ml) group (p < 0.05) and correlated with an increase in PVR (r = 0.623, p = 0.001; r = 0.530, p = 0.006, respectively). CONCLUSIONS: After 3 hours of warm ischemia topical cooling with Perfadex resulted in better graft function. Nitrite and protein levels in BAL correlated well with PVR and may therefore be used as a non-invasive marker to predict graft function for NHBDs.

Fibrinolytic treatment improves the quality of lungs retrieved from non-heart-beating donors.

BACKGROUND: The use of non-heart-beating donors (NHBDs) is an alternative strategy to increase the limited number of donors. The ex vivo evaluation has been proposed to assess the function of the lungs from NHBDs as an interim evaluation of the graft before transplantation. We evaluated the effect of a fibrinolytic agent, urokinase, in a pig ex vivo evaluation model. METHODS: Domestic pigs (30-38 kg) were divided in 3 groups of 5 pigs each. In the Control Heart-Beating Donor (HBD) Group, the lungs were flushed, explanted, and stored in cold solution (4 degrees C) of low potassium dextran for 4 hours. The pigs in the other 2 study groups were non-heart-beating donors (NHBD), and their lungs were topically cooled for 1 hour in the closed chest after 3 hours of warm ischemia. Urokinase (100,000 IU) was added into the perfusate during reperfusion 1n 1 of the NHBD groups (NHBD-UROK). Hemodynamic and aerodynamic parameters were measured. The wet-to-dry weight ratio was calculated. RESULTS: There was a significant difference between NHBD-UROK and NHBD Groups in pulmonary vascular resistance (22.5 +/- 3.06 vs 39.02 +/- 6.6 Wood Units, p = 0.032), partial pressure of arterial oxygen/fraction of inspired oxygen (250.8 +/- 23.3 vs 148.9 +/- 14.6 mm Hg, p = 0.032), oxygenation index (6.9 +/- 0.7 vs 15.9 +/- 3.2, p = 0.016), and wet-to-dry weight ratio (5.99 +/- 0.2 vs 7.74 +/- 0.3, p = 0.016). Pulmonary vascular resistance did not differ between the HBD and NHBD-UROK Groups but was significantly higher in the NHBD Group than in the HBD Group (p = 0.032). CONCLUSION: Adding urokinase into the perfusate during ex vivo evaluation resulted in improved graft function by reducing pulmonary vascular resistance and increasing oxygenation after 3 hours of warm ischemia. This ex vivo evaluation model is feasible and may be used to recondition grafts from NHBDs.