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Dimitrios Toumpanakis,1 Constantinos Glynos,1 Pinelopi Schoini,2 Vyronia Vassilakopoulou,1 Athanasia Chatzianastasiou,1 Maria Dettoraki,1 Eleftheria Mizi,1 Dionysios Tsoukalas,1 Fotis Perlikos,1 Christina Magkou,3 Andreas Papapetropoulos,4,5 Theodoros Vassilakopoulos1,6 1“Marianthi Simou” Applied Biomedical Research and Training Center, Medical School, National and Kapodistrian University of Athens, Evangelismos Hospital, Athens, Greece; 2 4th Respiratory Clinic, “Sotiria” General Hospital for Thoracic Diseases of Athens, Athens, Greece; 3Department of Pathology, Evangelismos Hospital, Athens, Greece; 4Biomedical Research Foundation of the Academy of Athens, Athens, Greece; 5Division of Pharmaceutical Chemistry, Department of Pharmacy, National and Kapodistrian University of Athens, Athens, Greece; 6Department of Physiology, Medical School, National and Kapodistrian University of Athens, Athens, GreeceCorrespondence: Dimitrios Toumpanakis, “Marianthi Simou” Applied Biomedical Research and Training Center, Medical School, National and Kapodistrian University of Athens, Evangelismos Hospital, 3rd Ploutarchou Street, 2nd Floor, Athens, 10675, Greece, Tel +302107235521, Email dtoumpanakis@yahoo.grIntroduction: Resistive breathing (RB) is characterized by forceful contractions of the inspiratory muscles, mainly the diaphragm, resulting in large negative intrathoracic pressure and mechanical stress imposed on the lung. We have shown that RB induces lung injury in healthy animals. Whether RB exerts additional injurious effects when added to pulmonary or extrapulmonary lung injury is unknown. Our aim was to study the synergistic effect of RB on lipopolysaccharide (LPS)-induced lung injury.Methods: C57BL/6 mice inhaled an LPS aerosol (10mg/3mL) or received an intraperitoneal injection of LPS (10 mg/kg). Mice were then anaesthetized, the trachea was surgically exposed, and a nylon band of a specified length was sutured around the trachea, to provoke a reduction of the surface area at 50%. RB through tracheal banding was applied for 24 hours. Respiratory system mechanics were measured, BAL was performed, and lung sections were evaluated for histological features of lung injury.Results: LPS inhalation increased BAL cellularity, mainly neutrophils (p < 0.001 to ctr), total protein and IL-6 in BAL (p < 0.001 and p < 0.001, respectively) and increased the lung injury score (p = 0.001). Lung mechanics were not altered. Adding RB to inhaled LPS further increased BAL cellularity (p < 0.001 to LPS inh.), total protein (p = 0.016), lung injury score (p = 0.001) and increased TNFa levels in BAL (p = 0.011). Intraperitoneal LPS increased BAL cellularity, mainly macrophages (p < 0.001 to ctr.), total protein levels (p = 0.017), decreased static compliance (p = 0.004) and increased lung injury score (p < 0.001). Adding RB further increased histological features of lung injury (p = 0.022 to LPS ip).Conclusion: Resistive breathing exerts synergistic injurious effects when combined with inhalational LPS-induced lung injury, while the additive effect on extrapulmonary lung injury is less prominent.Keywords: endotoxin, resistive breathing, lung, inflammation, injury

Dimitrios Toumpanakis,1 Athanasia Chatzianastasiou,1 Vyronia Vassilakopoulou,1 Eleftheria Mizi,1 Maria Dettoraki,1 Fotis Perlikos,1 Georgia Giatra,1,2 Nikolaos Mikos,3 Stamatios Theocharis,4 Theodoros Vassilakopoulos1,2 1“Marianthi Simou” Applied Biomedical Research and Training Center, Evangelismos Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece; 2 3rd Department of Critical Care Medicine, Evgenideio Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece; 3Allergology Department, Laiko General Hospital, Athens, Greece; 4First Department of Pathology, Medical School, National and Kapodistrian University of Athens, Athens, GreeceCorrespondence: Dimitrios Toumpanakis, Email dtoumpanakis@yahoo.grIntroduction: TRPV4 channels are calcium channels, activated by mechanical stress, that have been implicated in the pathogenesis of pulmonary inflammation. During resistive breathing (RB), increased mechanical stress is imposed on the lung, inducing lung injury. The role of TRPV4 channels in RB-induced lung injury is unknown.Materials and Methods: Spontaneously breathing adult male C57BL/6 mice were subjected to RB by tracheal banding. Following anaesthesia, mice were placed under a surgical microscope, the surface area of the trachea was measured and a nylon band was sutured around the trachea to reduce area to half. The specific TRPV4 inhibitor, HC-067047 (10 mg/kg ip), was administered either prior to RB and at 12 hrs following initiation of RB (preventive) or only at 12 hrs after the initiation of RB (therapeutic protocol). Lung injury was assessed at 24 hrs of RB, by measuring lung mechanics, total protein, BAL total and differential cell count, KC and IL-6 levels in BAL fluid, surfactant Protein (Sp)D in plasma and a lung injury score by histology.Results: RB decreased static compliance (Cst), increased total protein in BAL (p < 0.001), total cell count due to increased number of both macrophages and neutrophils, increased KC and IL-6 in BAL (p < 0.001 and p = 0.01, respectively) and plasma SpD (p < 0.0001). Increased lung injury score was detected. Both preventive and therapeutic HC-067047 administration restored Cst and inhibited the increase in total protein, KC and IL-6 levels in BAL fluid, compared to RB. Preventive TRPV4 inhibition ameliorated the increase in BAL cellularity, while therapeutic TRPV4 inhibition exerted a partial effect. TRPV4 inhibition blunted the increase in plasma SpD (p < 0.001) after RB and the increase in lung injury score was also inhibited.Conclusion: TRPV4 inhibition exerts protective effects against RB-induced lung injury.Keywords: resistive breathing, TRPV4, lung permeability, pulmonary inflammation

Dimitrios Toumpanakis,1,2 Eleftheria Mizi,1 Vyronia Vassilakopoulou,1 Maria Dettoraki,1 Athanasia Chatzianastasiou,1 Fotis Perlikos,1 Georgia Giatra,2 Marina Moscholaki,1 Stamatios Theocharis,3 Theodoros Vassilakopoulos1,2 1“Marianthi Simou” Applied Biomedical Research and Training Center, Medical School, University of Athens, Evangelismos Hospital, Athens, Greece; 2 3rd Department of Critical Care Medicine, Evgenideio Hospital, Medical School, University of Athens, Athens, Greece; 3Department of Pathology, Medical School, University of Athens, Athens, GreeceCorrespondence: Theodoros Vassilakopoulos 3rd Department of Critical Care Medicine, Evgenideio Hospital, Medical School, University of Athens, Athens, GreeceEmail tvassil@med.uoa.grIntroduction: Resistive breathing (RB), the pathophysiologic hallmark of chronic obstructive pulmonary disease (COPD), especially during exacerbations, is associated with significant inflammation and mechanical stress on the lung. Mechanical forces are implicated in the progression of emphysema that is a major pathologic feature of COPD. We hypothesized that resistive breathing exacerbates emphysema.Methods: C57BL/6 mice were exposed to 0.75 units of pancreatic porcine elastase intratracheally to develop emphysema. Resistive breathing was applied by suturing a nylon band around the trachea to reduce surface area to half for the last 24 or 72 hours of a 21-day time period after elastase treatment in total. Following RB (24 or 72 hours), lung mechanics were measured and bronchoalveolar lavage (BAL) was performed. Emphysema was quantified by the mean linear intercept (Lm) and the destructive index (DI) in lung tissue sections.Results: Following 21 days of intratracheal elastase exposure, Lm and DI increased in lung tissue sections [Lm (μm), control 39.09± 0.76, elastase 62.05± 2.19, p=0.003 and DI, ctr 30.95± 2.75, elastase 73.12± 1.75, p< 0.001]. RB for 72 hours further increased Lm by 64% and DI by 19%, compared to elastase alone (p< 0.001 and p=0.02, respectively). RB induced BAL neutrophilia in elastase-treated mice. Static compliance (Cst) increased in elastase-treated mice [Cst (mL/cmH2O), control 0.067± 0.001, elastase 0.109± 0.006, p< 0.001], but superimposed RB decreased Cst, compared to elastase alone [Cst (mL/cmH2O), elastase+RB24h 0.090± 0.004, p=0.006 to elastase, elastase+RB72h 0.090± 0.005, p=0.006 to elastase].Conclusion: Resistive breathing augments pulmonary inflammation and emphysema in an elastase-induced emphysema mouse model.Keywords: resistive breathing, elastase, emphysema, mechanical forces

Andreas Asimakos,1,2,* Dimitrios Toumpanakis,1,2,* Maria-Helena Karatza,3 Spyridoula Vasileiou,3 Paraskevi Katsaounou,1,2 Zafeiria Mastora,1,2 Theodoros Vassilakopoulos1,2,4 1GP Livanos and M Simou Laboratories, Thorax Foundation, 2Critical Care Department and Pulmonary Unit, Evangelismos Hospital, Medical School, National and Kapodistrian University of Athens, 3Flow Cytometry Unit, Hematology Clinic Evangelismos Hospital, 43rd Department of Critical Care Medicine, Evgenideion Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece *These authors contributed equally to this work Background/hypothesis: Whole body exercise (WBE) changes lymphocyte subset percentages in peripheral blood. Resistive breathing, a hallmark of diseases of airway obstruction, is a form of exercise for the inspiratory muscles. Strenuous muscle contractions induce oxidative stress that may mediate immune alterations following exercise. We hypothesized that inspiratory resistive breathing (IRB) alters peripheral blood lymphocyte subsets and that oxidative stress mediates lymphocyte subpopulation alterations following both WBE and IRB.Patients and methods: Six healthy nonathletes performed two WBE and two IRB sessions for 45 minutes at 70% of VO2 maximum and 70% of maximum inspiratory pressure (Pimax), respectively, before and after the administration of antioxidants (vitamins E, A, and C for 75 days, allopurinol for 30 days, and N-acetylcysteine for 3 days). Blood was drawn at baseline, at the end of each session, and 2 hours into recovery. Lymphocyte subsets were determined by flow cytometry.Results: Before antioxidant supplementation at both WBE end and IRB end, the natural killer cell percentage increased, the T helper cell (CD3+ CD4+) percentage was reduced, and the CD4/CD8 ratio was depressed, a response which was abolished by antioxidants only after IRB. Furthermore, at IRB end, antioxidants promoted CD8+ CD38+ and blunted cytotoxic T-cell percentage increase. CD8+ CD45RA+ cell percentage changes were blunted after antioxidant supplementation in both WBE and IRB.Conclusion: We conclude that IRB produces (as WBE) changes in peripheral blood lymphocyte subsets and that oxidative stress is a major stimulus predominantly for IRB-induced lymphocyte subset alterations. Keywords: resistive breathing, exercise, antioxidants, lymphocyte

Dimitrios Toumpanakis,1,2 Konstantinos Loverdos,1,2 Vassiliki Tzouda,1,2 Vyronia Vassilakopoulou,1,2 Eleni Litsiou,1,2 Christina Magkou,3 Vassiliki Karavana,1,2 Michael Pieper,4 Theodoros Vassilakopoulos1,2 1First Critical Care Department, Pulmonary Unit, National and Kapodistrian University of Athens Medical School, Evangelismos General Hospital, 2George P. Livanos and Marianthi Simou Laboratories, Thorax Foundation, 3Department of Pathology, Evangelismos General Hospital, Athens, Greece; 4Boehringer Ingelheim Pharma GmbH & Co. KG Div. Research Germany, Biberach, Germany Introduction: Resistive breathing (RB), a hallmark of obstructive airway diseases, is characterized by strenuous contractions of the inspiratory muscles that impose increased mechanical stress on the lung. RB is shown to induce pulmonary inflammation in previous healthy animals. Tiotropium bromide, an anticholinergic bronchodilator, is also shown to exert anti-inflammatory effects. The effect of tiotropium on RB-induced pulmonary inflammation is unknown.Methods: Adult rats were anesthetized, tracheostomized and breathed spontaneously through a two-way non-rebreathing valve. Resistances were connected to the inspiratory and/or expiratory port, to produce inspiratory resistive breathing (IRB) of 40% or 50% Pi/Pi,max (40% and 50% IRB), expiratory resistive breathing (ERB) of 60% Pe/Pe,max (60% ERB) or combined resistive breathing (CRB) of both 40% Pi/Pi,max and 60% Pe/Pe,max (40%/60% CRB). Tiotropium aerosol was inhaled prior to RB. After 6 h of RB, mechanical parameters of the respiratory system were measured and bronchoalveolar lavage (BAL) was performed. IL-1β and IL-6 protein levels were measured in lung tissue. Lung injury was estimated histologically.Results: In all, 40% and 50% IRB increased macrophage and neutrophil counts in BAL and raised IL-1β and IL-6 lung levels, tissue elasticity, BAL total protein levels and lung injury score. Tiotropium attenuated BAL neutrophil number, IL-1β, IL-6 levels and lung injury score increase at both 40% and 50% IRB. The increase in macrophage count and protein in BAL was only reversed at 40% IRB, while tissue elasticity was not affected. In all, 60% ERB raised BAL neutrophil count and total protein and reduced macrophage count. IL-1β and IL-6 levels and lung injury score were increased. Tiotropium attenuated these alterations, except for the decrease in macrophage count and the increase in total protein level. In all, 40%/60% CRB increased macrophage and neutrophil count in BAL, IL-1β and IL-6 levels, tissue elasticity, total protein in BAL and histological injury score. Tiotropium attenuated the aforementioned alterations.Conclusion: Tiotropium inhalation attenuates RB-induced pulmonary inflammation. Keywords: resistive breathing, inflammation, tiotropium bromide

Theodoros Vassilakopoulos, Dimitrios Toumpanakis Pulmonary and Critical Care Medicine, Medical School, National and Kapodistrian University of Athens, Greece Abstract: In obstructive lung diseases, airway inflammation leads to bronchospasm and thus resistive breathing, especially during exacerbations. This commentary discusses experimental evidence that resistive breathing per se (the mechanical stimulus) in the absence of underlying airway inflammation leads to lung injury and inflammation (mechanotransduction). The potential implications of resistive breathing-induced mechanotrasduction in COPD exacerbations are presented along with the available clinical evidence. Keywords: resistive breathing, COPD, mechanotransduction, bronchoconstriction, inflammation

Konstantinos Loverdos,1 Dimitrios Toumpanakis,1 Eleni Litsiou,1 Vassiliki Karavana,1 Constantinos Glynos,1 Christina Magkou,2 Stamatios Theocharis,3 Theodoros Vassilakopoulos1 1Department of Critical Care, Pulmonary Unit and Marianthi Simou Applied Biomedical Research and Training Center, Evangelismos General Hospital, University of Athens Medical School, 2Department of Pathology, Evangelismos General Hospital, 31st Department of Pathology, University of Athens Medical School, Athens, Greece Abstract: Combined resistive breathing (CRB) is the hallmark of obstructive airway disease pathophysiology. We have previously shown that severe inspiratory resistive breathing (IRB) induces acute lung injury in healthy rats. The role of expiratory resistance is unknown. The possibility of a load-dependent type of resistive breathing-induced lung injury also remains elusive. Our aim was to investigate the differential effects of IRB, expiratory resistive breathing (ERB), and CRB on healthy rat lung and establish the lowest loads required to induce injury. Anesthetized tracheostomized rats breathed through a two-way valve. Varying resistances were connected to the inspiratory, expiratory, or both ports, so that the peak inspiratory pressure (IRB) was 20%–40% or peak expiratory (ERB) was 40%–70% of maximum. CRB was assessed in inspiratory/expiratory pressures of 30%/50%, 40%/50%, and 40%/60% of maximum. Quietly breathing animals served as controls. At 6 hours, respiratory system mechanics were measured, and bronchoalveolar lavage was performed for measurement of cell and protein concentration. Lung tissue interleukin-6 and interleukin-1β levels were estimated, and a lung injury histological score was determined. ERB produced significant, load-independent neutrophilia, without mechanical or permeability derangements. IRB 30% was the lowest inspiratory load that provoked lung injury. CRB increased tissue elasticity, bronchoalveolar lavage total cell, macrophage and neutrophil counts, protein and cytokine levels, and lung injury score in a dose-dependent manner. In conclusion, CRB load dependently deranges mechanics, increases permeability, and induces inflammation in healthy rats. ERB is a putative inflammatory stimulus for the lung. Keywords: resistive breathing, lung injury, inflammation

Rationale: Resistive breathing is associated with large negative intrathoracic pressures. Increased mechanical stress induces high-permeability pulmonary edema and lung inflammation. Objectives: To determine the effects of resistive breathing on the healthy lung. Methods: Anesthetized rats breathed through a two-way nonrebreathing valve. The inspiratory line was connected to a resistance setting peak inspiratory tracheal pressure at 50% of maximum (inspiratory resistive breathing), while 100% oxygen was supplied to prevent hypoxemia. Quietly breathing animals (100% oxygen) served as controls. Lung injury was evaluated after 3 and 6 hours of resistive breathing. Measurements and Main Results: After both 3 and 6 hours of resistive breathing, lung permeability was increased, as assessed by (99m)Tc-diethylenetriaminepentaacetic acid scintigraphy and Evans blue dye extravasation. Tissue elasticity, measured on the basis of static pressure-volume curves and by the low-frequency forced oscillation technique, was also increased. After both 3 and 6 hours of resistive breathing, gravimetric measurements revealed the presence of pulmonary edema and analysis of bronchoalveolar lavage showed increased total protein content, whereas the total cell count was elevated only after 6 hours of resistive breathing. Cytokine levels were assessed in bronchoalveolar lavage fluid and lung tissue by ELISA and were increased after 6 hours compared with controls. Western blot analysis showed early activation of Src kinase via phosphorylation (at 30 min), and Erk1/2 and I[kappa]B[alpha] (nuclear factor-[kappa]B inhibitor) were phosphorylated at 3 and 6 hours. Pathology revealed the presence of lung injury after resistive breathing. Conclusions: Resistive breathing induces acute lung injury and inflammation. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the predictive value and clinical impact of a clinically implemented artificial neural network software model. The software detects intracranial hemorrhage (ICH) from head computed tomography (CT) scans and artificial intelligence (AI)-identified positive cases are then annotated in the work list for early radiologist evaluation. The index test was AI detection by the program Zebra Medical Vision-HealthICH+. Radiologist-confirmed ICH was the reference standard. The study compared whether time benefits from using the AI model led to faster escalation of patient care or surgery within the first 24 h. A total of 2,306 patients were evaluated by the software, and 288 AI-positive cases were included. The AI tool had a positive predictive value of 0.823. There was, however, no significant time reduction when comparing the patients who required escalation of care and those who did not. There was also no significant time reduction in those who required acute surgery compared with those who did not. Among the individual patients with reduced time delay, no cases with evident clinical benefit were identified. Although the clinically implemented AI-based decision support system showed adequate predictive value in identifying ICH, there was no significant clinical benefit for the patients in our setting. While AI-assisted detection of ICH shows great promise from a technical perspective, there remains a need to evaluate the clinical impact and perform external validation across different settings., (© The Author(s) 2024. Published by Mary Ann Liebert, Inc.)

Purpose: To develop a deep learning-based algorithm that automatically and accurately classifies patients as either having pulmonary emboli or not in CT pulmonary angiography (CTPA) examinations., Materials and Methods: For model development, 700 CTPA examinations from 652 patients performed at a single institution were used, of which 149 examinations contained 1497 PE traced by radiologists. The nnU-Net deep learning-based segmentation framework was trained using 5-fold cross-validation. To enhance classification, we applied logical rules based on PE volume and probability thresholds. External model evaluation was performed in 770 and 34 CTPAs from two independent datasets., Results: A total of 1483 CTPA examinations were evaluated. In internal cross-validation and test set, the trained model correctly classified 123 of 128 examinations as positive for PE (sensitivity 96.1 %; 95 % C.I. 91-98 %; P < .05) and 521 of 551 as negative (specificity 94.6 %; 95 % C.I. 92-96 %; P < .05), achieving an area under the receiver operating characteristic (AUROC) of 96.4 % (95 % C.I. 79-99 %; P < .05). In the first external test dataset, the trained model correctly classified 31 of 32 examinations as positive (sensitivity 96.9 %; 95 % C.I. 84-99 %; P < .05) and 2 of 2 as negative (specificity 100 %; 95 % C.I. 34-100 %; P < .05), achieving an AUROC of 98.6 % (95 % C.I. 83-100 %; P < .05). In the second external test dataset, the trained model correctly classified 379 of 385 examinations as positive (sensitivity 98.4 %; 95 % C.I. 97-99 %; P < .05) and 346 of 385 as negative (specificity 89.9 %; 95 % C.I. 86-93 %; P < .05), achieving an AUROC of 98.5 % (95 % C.I. 83-100 %; P < .05)., Conclusion: Our automatic pipeline achieved beyond state-of-the-art diagnostic performance of PE in CTPA using nnU-Net for segmentation and volume- and probability-based post-processing for classification., Competing Interests: The authors declare that they have no conflicts of interest., (© 2024 The Authors.)

Radiological imaging to examine intracranial blood vessels is critical for preoperative planning and postoperative follow-up. Automated segmentation of cerebrovascular anatomy from Time-Of-Flight Magnetic Resonance Angiography (TOF-MRA) can provide radiologists with a more detailed and precise view of these vessels. This paper introduces a domain generalized artificial intelligence (AI) solution for volumetric monitoring of cerebrovascular structures from multi-center MRAs. Our approach utilizes a multi-task deep convolutional neural network (CNN) with a topology-aware loss function to learn voxel-wise segmentation of the cerebrovascular tree. We use Decorrelation Loss to achieve domain regularization for the encoder network and auxiliary tasks to provide additional regularization and enable the encoder to learn higher-level intermediate representations for improved performance. We compare our method to six state-of-the-art 3D vessel segmentation methods using retrospective TOF-MRA datasets from multiple private and public data sources scanned at six hospitals, with and without vascular pathologies. The proposed model achieved the best scores in all the qualitative performance measures. Furthermore, we have developed an AI-assisted Graphical User Interface (GUI) based on our research to assist radiologists in their daily work and establish a more efficient work process that saves time., (© 2024. The Author(s).)

Segmentation of major brain vessels is very important for the diagnosis of cerebrovascular disorders and subsequent surgical planning. Vessel segmentation is an important preprocessing step for a wide range of algorithms for the automatic diagnosis or treatment of several vascular pathologies and as such, it is valuable to have a well-performing vascular segmentation pipeline. In this article, we propose an end-to-end multiscale residual dual attention deep neural network for resilient major brain vessel segmentation. In the proposed network, the encoder and decoder blocks of the U-Net are replaced with the multi-level atrous residual blocks to enhance the learning capability by increasing the receptive field to extract the various semantic coarse- and fine-grained features. Dual attention block is incorporated in the bottleneck to perform effective multiscale information fusion to obtain detailed structure of blood vessels. The methods were evaluated on the publicly available TubeTK data set. The proposed method outperforms the state-of-the-art techniques with dice of 0.79 on the whole-brain prediction. The statistical and visual assessments indicate that proposed network is robust to outliers and maintains higher consistency in vessel continuity than the traditional U-Net and its variations.

Mediastinal structure measurements are important for the radiologist's review of computed tomography pulmonary angiography (CTPA) examinations. In the reporting process, radiologists make measurements of diameters, volumes, and organ densities for image quality assessment and risk stratification. However, manual measurement of these features is time consuming. Here, we sought to develop a time-saving automated algorithm that can accurately detect, segment and measure mediastinal structures in routine clinical CTPA examinations. In this study, 700 CTPA examinations collected and annotated. Of these, a training set of 180 examinations were used to develop a fully automated deterministic algorithm. On the test set of 520 examinations, two radiologists validated the detection and segmentation performance quantitatively, and ground truth was annotated to validate the measurement performance. External validation was performed in 47 CTPAs from two independent datasets. The system had 86-100% detection and segmentation accuracy in the different tasks. The automatic measurements correlated well to those of the radiologist (Pearson's r 0.68-0.99). Taken together, the fully automated algorithm accurately detected, segmented, and measured mediastinal structures in routine CTPA examinations having an adequate representation of common artifacts and medical conditions., (© 2023. The Author(s).)

Background: The aim of this review is to summarize the current evidence regarding small airway disease in asthma, focusing on recent advances in small airway pathophysiology, assessment and therapeutic implications., Methods: A search in Medline was performed, using the keywords "small airways", "asthma", "oscillometry", "nitrogen washout" and "imaging". Our review was based on studies from adult asthmatic patients, although evidence from pediatric populations is also discussed., Results: In asthma, inflammation in small airways, increased mucus production and airway wall remodelling are the main pathogenetic mechanisms of small airway disease. Small airway dysfunction is a key component of asthma pathophysiology, leading to increased small airway resistance and airway closure, with subsequent ventilation inhomogeneities, hyperresponsiveness and airflow limitation. Classic tests of lung function, such as spirometry and body plethysmography are insensitive to detect small airway disease, providing only indirect measurements. As discussed in our review, both functional and imaging techniques that are more specific for small airways, such as oscillometry and the multiple breath nitrogen washout have delineated the role of small airways in asthma. Small airways disease is prevalent across all asthma disease stages and especially in severe disease, correlating with important clinical outcomes, such as asthma control and exacerbation frequency. Moreover, markers of small airways dysfunction have been used to guide asthma treatment and monitor response to therapy., Conclusions: Assessment of small airway disease provides unique information for asthma diagnosis and monitoring, with potential therapeutic implications., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Omar Usmani reports a relationship with Astra Zeneca that includes: consulting or advisory, funding grants, speaking and lecture fees, and travel reimbursement. Omar Usmani reports a relationship with Boehringer Ingelheim that includes: consulting or advisory, funding grants, speaking and lecture fees, and travel reimbursement. Omar Usmani reports a relationship with Chiesi Pharmaceuticals Inc that includes: consulting or advisory, funding grants, speaking and lecture fees, and travel reimbursement. Omar Usmani reports a relationship with Covis Pharma that includes: consulting or advisory, speaking and lecture fees, and travel reimbursement. Dimitrios Toumpanakis reports a relationship with Chiesi Pharmaceuticals Inc that includes: speaking and lecture fees. Dimitrios Toumpanakis reports a relationship with Menarini that includes: speaking and lecture fees. Dimitrios Toumpanakis reports a relationship with Elpen Pharmaceuticals that includes: speaking and lecture fees., (© 2023 The Author(s).)

Alpha-1 antitrypsin deficiency (AATD) is a genetic disorder, characterized by panacinar emphysema mainly in the lower lobes, and predisposes to chronic obstructive pulmonary disease (COPD) at a younger age, especially in patients with concomitant cigarette smoking. Alpha-1 antitrypsin (a1-AT) is a serine protease inhibitor that mainly blocks neutrophil elastase and maintains protease/antiprotease balance in the lung and AATD is caused by mutations in the SERPINA1 gene that encodes a1-AT protein. PiZZ is the most common genotype associated with severe AATD, leading to reduced circulating levels of a1-AT. Besides its antiprotease function, a1-AT has anti-inflammatory and antioxidative effects and AATD results in defective innate immunity. Protease/antiprotease imbalance affects not only the lung parenchyma but also the small airways and recent studies have shown that AATD is associated with small airway dysfunction. Alterations in small airways structure with peripheral ventilation inhomogeneities may precede emphysema formation, providing a unique opportunity to detect early disease. The aim of the present review is to summarize the current evidence for the contribution of small airways disease in AATD-associated lung disease., Competing Interests: Declaration of competing interest DT has received honoraria for presentations from Menarini, Chiesi and ELPEN pharmaceutical company. OSU reports grants and personal fees from Astra Zeneca, Boehringer Ingelheim, Chiesi, Glaxosmithkline, personal fees from Cipla, Covis, Deva, Kamada, Kyorin, Napp, Novartis, Orion, Menarini, Mereobiopharma, Mundipharma, Trudell Medical, UCB, Sandoz, Takeda, grants from Edmond outside the submitted work., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Proinflammatory cytokines like interleukin-1β (IL-1β) affect the control of breathing. Our aim is to determine the effect of the anti-inflammatory cytokine IL-10 οn the control of breathing. IL-10 knockout mice (IL-10 -/- , n = 10) and wild-type mice (IL-10 +/+ , n = 10) were exposed to the following test gases: hyperoxic hypercapnia 7% CO 2 -93% O 2 , normoxic hypercapnia 7% CO 2 -21% O 2 , hypoxic hypercapnia 7% CO 2 -10% O 2 , and hypoxic normocapnia 3% CO 2 -10% O 2 . The ventilatory function was assessed using whole body plethysmography. Recombinant mouse IL-10 (rIL-10; 10 μg/kg) was administered intraperitoneally to wild-type mice ( n = 10) 30 min before the onset of gas challenge. IL-10 was administered in neonatal medullary slices (10-30 ng/ml, n = 8). We found that IL-10 -/- mice exhibited consistently increased frequency and reduced tidal volume compared with IL-10 +/+ mice during room air breathing and in all test gases (by 23.62 to 33.2%, P < 0.05 and -36.23 to -41.69%, P < 0.05, respectively). In all inspired gases, the minute ventilation of IL-10 -/- mice was lower than IL-10 +/+ (by -15.67 to -22.74%, P < 0.05). The rapid shallow breathing index was higher in IL-10 -/- mice compared with IL-10 +/+ mice in all inspired gases (by 50.25 to 57.5%, P < 0.05). The intraperitoneal injection of rIL-10 caused reduction of the respiratory rate and augmentation of the tidal volume in room air and also in all inspired gases (by -12.22 to -29.53 and 32.18 to 45.11%, P < 0.05, respectively). IL-10 administration in neonatal rat ( n = 8) in vitro rhythmically active medullary slice preparations did not affect either rhythmicity or peak amplitude of hypoglossal nerve discharge. In conclusion, IL-10 may induce a slower and deeper pattern of breathing.

Lung cancer and chronic lung diseases impose major disease burdens worldwide and are caused by inhaled noxious agents including tobacco smoke. The cellular origins of environmental-induced lung tumors and of the dysfunctional airway and alveolar epithelial turnover observed with chronic lung diseases are unknown. To address this, we combined mouse models of genetic labeling and ablation of airway (club) and alveolar cells with exposure to environmental noxious and carcinogenic agents. Club cells are shown to survive KRAS mutations and to form lung tumors after tobacco carcinogen exposure. Increasing numbers of club cells are found in the alveoli with aging and after lung injury, but go undetected since they express alveolar proteins. Ablation of club cells prevents chemical lung tumors and causes alveolar destruction in adult mice. Hence club cells are important in alveolar maintenance and carcinogenesis and may be a therapeutic target against premalignancy and chronic lung disease., Competing Interests: MS, IL, MP, YC, MA, AL, DZ, FR, MV, NK, DW, AG, VA, KA, LK, DT, VK, SZ, IG, AM, VA, RS, GS No competing interests declared, (© 2019, Spella et al.)

Background: We aimed to examine the predictive value of a novel mathematical formula based on the law of conservation of mass in calculating sodium changes in intensive care unit patients and compare its performance with previously published formulae., Methods: 178 patients were enrolled from 01/2010 to 10/2013. Plasma and urine were collected in two consecutive 8-hour intervals and the sodium was measured. The predicted sodium concentration was calculated based on previous equations and our formula. The two 8-hour period (epoch 1 and 2) results were compared. Variability of predicted values among the measured range of serum sodium levels were provided by Bland-Altman plots with bias and precision statistics. Comparison of the results was performed with the statistical model of the Percentage Similarity., Results: 47.19% patients had dysnatremias. The bias ± SD with 95% limits of agreement for sodium levels were -1.395±3.491 for epoch 1 and -1.623 ±11.1 for epoch 2 period. Bland-Altman analysis for the epoch 1 study period had the following results: -0.8079±3.447 for Adrogué-Madias, 0.56±9.687 for Barsoum-Levine, 0.1412±3.824 for EFWC and 0.294±4.789 for Kurtz-Nguyen formula. The mean similarity, SD and coefficient variation for the methods compared with the measured sodium are: 99.56%, 3.873, 3.89% epoch 1, 99.56%, 1.255, 1.26% for epoch 2, 99.77%, 1.245, 1.26% for Adrogue-Madias, 100.1%, 1.337, 1.34% for Barsoum-Levine, 100.1%, 1.704, 1.7% for Nguyen, 100.1%, 1.370, 1.37% for ECFW formula., Conclusions: The law of conservation of mass can be successfully applied for the prediction of sodium changes in critically ill patients., Competing Interests: The authors have declared that no competing interests exist.

Inspiratory resistive breathing (IRB), a hallmark of obstructive airway diseases, is associated with strenuous contractions of the inspiratory muscles and increased negative intrathoracic pressures that act as an injurious stimulus to the lung. We have shown that IRB induces pulmonary inflammation in healthy animals. p38 kinase is activated in the lung under stress. We hypothesized that p38 is activated during IRB and contributes to IRB-induced pulmonary inflammation. Anesthetized, tracheostomized rats breathed spontaneously through a two-way valve. Resistance was connected to the inspiratory port to provoke a peak tidal inspiratory pressure 50% of maximum. Following 3 and 6 h of IRB, respiratory system mechanics were measured and bronchoalveolar lavage (BAL) was performed. Phosphorylated p38, TNF-α, and MIP-2α were detected in lung tissue. Lung injury was estimated histologically. SB203580 (p38 inhibitor) was administered prior to IRB (1 mg kg -1 ). Six hours of IRB increased phosphorylated p38 in the lung, compared with quietly breathing controls (p = 0.001). Six hours of IRB increased the numbers of macrophages and neutrophils (p = 0.01 and p = 0.005) in BAL fluid. BAL protein levels and lung elasticity increased after both 3 and 6 h IRB. TNF-α and MIP-2α increased after 6 h of IRB (p = 0.01 and p < 0.001, respectively). Increased lung injury score was detected at 6 h IRB. SB203580 administration blocked the increase of neutrophils and macrophages at 6 h IRB (p = 0.01 and p = 0.005 to 6 h IRB) but not the increase in BAL protein and elasticity. TNF-α, MIP-2α, and injury score at 6 h IRB returned to control. p38 activation contributes to IRB-induced pulmonary inflammation.

Background: Inspiratory resistive breathing (IRB), a hallmark of obstructive airway diseases, is associated with large negative intrathoracic pressures, due to strenuous contractions of the inspiratory muscles. IRB is shown to induce lung injury in previously healthy animals. Src is a multifunctional kinase that is activated in the lung by mechanical stress. ERK1/2 kinase is a downstream target of Src. We hypothesized that Src is activated in the lung during IRB, mediates ERK1/2 activation and IRB-induced lung injury., Methods: Anaesthetized, tracheostomized adult rats breathed spontaneously through a 2-way non-rebreathing valve. Resistance was added to the inspiratory port to provide a peak tidal inspiratory pressure of 50% of maximum (inspiratory resistive breathing). Activation of Src and ERK1/2 in the lung was estimated during IRB. Following 6 h of IRB, respiratory system mechanics were measured by the forced oscillation technique and bronchoalveolar lavage (BAL) was performed to measure total and differential cell count and total protein levels. IL-1b and MIP-2a protein levels were measured in lung tissue samples. Wet lung weight to total body weight was measured and Evans blue dye extravasation was estimated to measure lung permeability. Lung injury was evaluated by histology. The Src inhibitor, PP-2 or the inhibitor of ERK1/2 activation, PD98059 was administrated 30 min prior to IRB., Results: Src kinase was activated 30 min after the initiation of IRB. Src inhibition ameliorated the increase in BAL cellularity after 6 h IRB, but not the increase of IL-1β and MIP-2a in the lung. The increase in BAL total protein and lung injury score were not affected. The increase in tissue elasticity was partly inhibited. Src inhibition blocked ERK1/2 activation at 3 but not at 6 h of IRB. ERK1/2 inhibition ameliorated the increase in BAL cellularity after 6 h of IRB, blocked the increase of IL-1β and returned Evans blue extravasation and wet lung weight to control values. BAL total protein and the increase in elasticity were partially affected. ERK1/2 inhibition did not significantly change total lung injury score compared to 6 h IRB., Conclusions: Src and ERK1/2 are activated in the lung following IRB and participate in IRB-induced lung injury.

Cigarette smoking is one of the risk factors for coronary artery disease. Although conditioning decreases infarct size in hearts from healthy animals, comorbidities may render it ineffective. We investigated the effects of cigarette smoke (CS) exposure on intracellular myocardial signaling, infarct size after ischemia-reperfusion, and the potential interference with ischemic conditioning. Exposure of mice to CS increased blood pressure, caused cardiac hypertrophy, and upregulated the nitric oxide synthatse (NOS)/soluble guanylate cyclase (sGC)/cGMP pathway. To test the effect of CS exposure on the endogenous cardioprotective mechanisms, mice were subjected to regional myocardial ischemia and reperfusion with no further intervention or application of preconditioning (PreC) or postconditioning (PostC). Exposure to CS did not increase the infarction compared with the room air (RA)-exposed group. PreC was beneficial for both CS and RA vs. nonconditioned animals. PostC was effective only in RA animals, while the infarct size-limiting effect was not preserved in the CS group. Differences in oxidative stress markers, Akt, and endothelial NOS phosphorylation and cGMP levels were observed between RA and CS groups subjected to PostC. In conclusion, exposure to CS does not per se increase infarct size. The beneficial effect of ischemic PreC is preserved in mice exposed to CS, as it does not affect the cardioprotective signaling; in contrast, PostC fails to protect CS-exposed mice due to impaired activation of the Akt/eNOS/cGMP axis that occurs in parallel to enhanced oxidative stress., (Copyright © 2016 the American Physiological Society.)

Inspiratory resistive breathing (RB), encountered in obstructive lung diseases, induces lung injury. The soluble guanylyl cyclase (sGC)/cyclic guanosine monophosphate (cGMP) pathway is down-regulated in chronic and acute animal models of RB, such as asthma, chronic obstructive pulmonary disease, and in endotoxin-induced acute lung injury. Our objectives were to: (1) characterize the effects of increased concurrent inspiratory and expiratory resistance in mice via tracheal banding; and (2) investigate the contribution of the sGC/cGMP pathway in RB-induced lung injury. Anesthetized C57BL/6 mice underwent RB achieved by restricting tracheal surface area to 50% (tracheal banding). RB for 24 hours resulted in increased bronchoalveolar lavage fluid cellularity and protein content, marked leukocyte infiltration in the lungs, and perturbed respiratory mechanics (increased tissue resistance and elasticity, shifted static pressure-volume curve right and downwards, decreased static compliance), consistent with the presence of acute lung injury. RB down-regulated sGC expression in the lung. All manifestations of lung injury caused by RB were exacerbated by the administration of the sGC inhibitor, 1H-[1,2,4]oxodiazolo[4,3-]quinoxalin-l-one, or when RB was performed using sGCα1 knockout mice. Conversely, restoration of sGC signaling by prior administration of the sGC activator BAY 58-2667 (Bayer, Leverkusen, Germany) prevented RB-induced lung injury. Strikingly, direct pharmacological activation of sGC with BAY 58-2667 24 hours after RB reversed, within 6 hours, the established lung injury. These findings raise the possibility that pharmacological targeting of the sGC-cGMP axis could be used to ameliorate lung dysfunction in obstructive lung diseases.

Inspiratory resistive breathing (IRB) is characterized by large negative intrathoracic pressures and was shown to induce pulmonary inflammation in previously healthy rats. Matrix metalloproteinases (MMP)-9 and -12 are induced by inflammation and mechanical stress in the lung. We hypothesized that IRB induces MMP-9 and -12 in the lung. Anesthetized, tracheostomized rats breathed spontaneously through a two-way valve, connected to an inspiratory resistance, with the tidal inspiratory tracheal pressure set at 50% of the maximum. Quietly breathing animals served as controls. After 3 and 6 h of IRB, respiratory mechanics were measured, bronchoalveolar lavage (BAL) was performed, lung injury score was estimated, and lung MMP-9 was estimated by zymography and ELISA. MMP-9 and MMP-12 immunohistochemistry was performed. Isolated normal alveolar macrophages were incubated with BAL from rats that underwent IRB. After 18 h, MMP-9 and -12 levels were measured in supernatants, and immunocytochemistry was performed. Macrophages were treated with IL-1β, IL-6, or TNF-α, and MMP-9 in supernatants was measured. After 6 h of IRB, leukocytes in BAL increased, and IL-1β and IL-6 levels were elevated. Elasticity and injury score were increased after 3 and 6 h of IRB. Lung MMP-9 levels increased after 6 h of IRB. MMP-9 and MMP-12 were detected in alveolar macrophages and epithelial (bronchial/alveolar) cells after 3 and 6 h of IRB. MMP-9 and MMP-12 were found in supernatants after treatment with 6 h of IRB BAL. Cytosolic immunostaining was detected after treatment with 3 and 6 h of IRB BAL. All cytokines induced MMP-9 in culture supernatants. In conclusion, IRB induces MMP-9 and -12 in the lung of previously healthy rats., (Copyright © 2015 the American Physiological Society.)

Intratracheal administration of lipopolysaccharide (LPS) in animals is a commonly used model of acute lung injury, characterized by increased alveolar-capillary membrane permeability causing protein-rich edema, inflammation, deterioration of lung mechanical function and impaired gas exchange. Technetium-99-m-labeled diethylene-triamine pentaacetatic acid ((99m)Tc-DTPA) scintigraphy is a non-invasive technique to assess lung epithelial permeability. We hypothesize that the longer the exposure and the higher the dose of LPS the greater the derangement of the various indices of lung injury. After 3, 6 and 24 h of 5 or 40 μg LPS intratracheally administration, (99m)Tc-DTPA was instilled in the lung. Images were acquired for 90 min with a γ-camera and the radiotracer clearance was estimated. In another subgroup, the mechanical properties of the respiratory system were estimated with the forced oscillation technique and static pressure-volume curves, 4.5, 7.5 and 25.5 h post-LPS (iso-times with the end of (99m)Tc-DTPA scintigraphy). Bronchoalveolar lavage (BAL) was performed and a lung injury score was estimated by histology. Lung myeloperoxidase (MPO) activity was measured. (99m)Tc-DTPA clearance increased in all LPS challenged groups compared with control. DTPA clearance presented a U-shape time course at the lower dose, while LPS had a declining effect over time at the larger dose. At 7.5 and 25.5 h post-LPS, tissue elasticity was increased and static compliance decreased at both doses. Total protein in the BAL fluid increased at both doses only at 4.5 h Total lung injury score and MPO activity were elevated in all LPS-treated groups. There is differential time- and dose-dependency of the various indices of lung injury after intratracheally LPS instillation in rats.

Resistive breathing (encountered in chronic obstructive pulmonary disease and asthma) results in cytokine upregulation and decreased nitric oxide (NO) levels in the strenuously contracting diaphragm. NO can regulate gene expression. We hypothesized that endogenously produced NO downregulates cytokine production triggered by strenuous diaphragmatic contraction. Wistar rats treated with vehicle, the nonselective NO synthase inhibitor NG-nitro-l-arginine-methylester (l-NAME), or the NO donor diethylenetriamine-NONOate (DETA) were subjected to inspiratory resistive breathing (IRB; 50% of maximal inspiratory pressure) for 6 h or sham operation. Additional groups of rats were subjected to IRB for 6 h with concurrent administration of l-NAME and inhibitors of NF-κB (BAY-11-7082), ERK1/2 (PD98059), or P38 (SB203580). Inhibition of NO production (with l-NAME) resulted in upregulation of IRB-induced diaphragmatic IL-6, IL-10, IL-2, TNF-α, and IL-1β levels by 50%, 53%, 60%, 47%, and 45%, respectively. In contrast, the NO donor (DETA) attenuated the IRB-induced cytokine upregulation to levels characteristic of quietly breathing animals. l-NAME augmented IRB-induced activation of MAPKs (P38 and ERK1/2) and NF-κB, whereas DETA triggered the opposite effect. NF-κB and ERK1/2 inhibition in l-NAME-treated animals blunted the l-NAME-induced cytokine upregulation except IL-6, whereas P38 inhibition blunted all (including IL-6) cytokine upregulation. NO downregulates IRB-induced cytokine production in the strenuously contracting diaphragm through its action on MAPKs and NF-κB.

Malignant mesothelioma (MM) is an aggressive tumor of serosal surfaces with increasing incidence and poor prognosis. Asbestos exposure is the main cause of MM and asbestos-induced DNA damage is critical for MM pathogenesis. The present review summarizes the implications of DNA repair systems in MM development, focusing on gene expression alterations and single nucleotide polymorphisms of genes encoding for DNA repair enzymes. The involvement of DNA repair systems in MM improves understanding of MM pathogenesis and provides novel therapeutical targets., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Inspiratory resistive breathing (IRB) induces cytokine expression in the diaphragm. The mechanism of this cytokine induction remains elusive. The roles of MAPKs and NF-κB and the impact of oxidative stress in IRB-induced cytokine upregulation in the diaphragm were studied. Wistar rats were subjected to IRB (50% of maximal inspiratory pressure) via a two-way nonrebreathing valve for 1, 3, or 6 h. Additional groups of rats subjected to IRB for 6 h were randomly assigned to receive either solvent or N-acetyl-cysteine (NAC) or inhibitors of NF-κB (BAY-11-7082), ERK1/2 (PD98059), and P38 MAPK (SB203580) to study the effect of oxidative stress, NF-κB, and MAPKs in IRB-induced cytokine upregulation in the diaphragm. Quietly breathing animals served as controls. IRB upregulated cytokine (IL-6, TNF-α, IL-10, IL-2, IL-1β) protein levels in the diaphragm and resulted in increased activation of MAPKs (P38, ERK1/2) and NF-κB. Inhibition of NF-κB and ERK1/2 blunted the upregulation of all cytokines except that of IL-6, which was further increased. P38 inhibition attenuated all cytokine (including IL-6) upregulation. Both P38 and ERK1/2 inhibition decreased NF-κB/p65 subunit phosphorylation. NAC pretreatment blunted IRB-induced cytokine upregulation in the diaphragm and resulted in decreased ERK1/2, P38, and NF-κB/p65 phosphorylation. In conclusion, IRB-induced cytokine upregulation in the diaphragm is under the regulatory control of MAPKs and NF-κB. IL-6 is regulated differently from all other cytokines through a P38-dependent and NF-κB independent pathway. Oxidative stress is a stimulus for IRB-induced cytokine upregulation in the diaphragm.

We studied in 10 healthy subjects the effect of chronic enteral supplementation of antioxidants (vitamins E, C, A, allopurinol, and N-acetylcysteine) on cytokine production by monocytes at rest, end exercise (60-min cycling at 60% of maximum oxygen consumption), and 60 min post-exercise (recovery). The percentage and the mean fluorescent intensity (MFI) of both unstimulated and lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6-producing monocytes were detected using flow cytometry. Antioxidants decreased the percentage of unstimulated IL-6-producing monocytes following exercise, while their MFI increased at rest. The percentage of LPS-stimulated monocytes increased after exercise and they produced more IL-6 both at rest and following exercise. The percentage of unstimulated and LPS-stimulated IL-1beta-producing monocytes was not affected by antioxidants. The MFI of IL-1beta-produced unstimulated monocytes was increased after antioxidants both at rest and following exercise. After antioxidants, LPS-stimulated monocytes produced more IL-1beta following exercise. Antioxidants decreased the percentage of TNF-alpha spontaneously-produced monocytes following exercise, which produced more TNF-alpha at recovery. Antioxidants did not affect the percentage of LPS-stimulated monocytes producing TNF-alpha, while LPS-stimulated production of TNF-alpha increased both at rest and following exercise. Antioxidants differentially affect TNF-alpha, IL-1beta, and IL-6 production by monocytes, with a general tendency of augmenting cytokine production.

Rationale: The angiopoietins (Ang) comprise a family of growth factors mainly known for their role in blood vessel formation and remodeling. The best-studied member, Ang-1, exhibits antiapoptotic and antiinflammatory effects. Although the involvement of Ang-1 in angiogenesis is well recognized, little information exists about its role in respiratory physiology and disease. On the basis of its ability to inhibit vascular permeability, adhesion molecule expression, and cytokine production, we hypothesized that Ang-1 administration might exert a protective role in asthma., Objectives: To determine changes in the expression of Ang and to assess the ability of Ang-1 to prevent the histologic, biochemical, and functional changes observed in an animal model of asthma., Methods: To test our hypothesis, a model of allergic airway disease that develops after ovalbumin (OVA) sensitization and challenge was used., Measurements and Main Results: Ang-1 expression was reduced at the mRNA and protein levels in lung tissue of mice sensitized and challenged with OVA, leading to reduced Tie2 phosphorylation. Intranasal Ang-1 treatment prevented the OVA-induced eosinophilic lung infiltration, attenuated the increase in IL-5 and IL-13, and reduced eotaxin and vascular cell adhesion molecule 1 expression. These antiinflammatory actions of Ang-1 coincided with higher levels of IkappaB and decreased nuclear factor-kappaB binding activity. More importantly, Ang-1 reversed the OVA-induced increase in tissue resistance and elastance, improving lung function., Conclusions: We conclude that Ang-1 levels are decreased in asthma and that administration of Ang-1 might be of therapeutic value because it prevents the increased responsiveness of the airways to constrictors and ameliorates inflammation.