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(‒)-Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea. Thanks to multiple interactions with cell surface receptors, intracellular signaling pathways, and nuclear transcription factors, EGCG possesses a wide variety of anti-inflammatory, antioxidant, antifibrotic, anti-remodelation, and tissue-protective properties which may be useful in the treatment of various diseases, particularly in cancer, and neurological, cardiovascular, respiratory, and metabolic disorders. This article reviews current information on the biological effects of EGCG in the above-mentioned disorders in relation to molecular pathways controlling inflammation, oxidative stress, and cell apoptosis.

Acute lung injury is characterized by acute respiratory insufficiency with tachypnea, cyanosis refractory to oxygen, decreased lung compliance, and diffuse alveolar infiltrates on chest X-ray. The 1994 American-European Consensus Conference defined “acute respiratory distress syndrome, ARDS” by acute onset after a known trigger, severe hypoxemia defined by PaO2/FiO2≤200 mm Hg, bilateral infiltrates on chest X-ray, and absence of cardiogenic edema. Milder form of the syndrome with PaO2/FiO2 between 200-300 mm Hg was named „acute lung injury, ALI“. Berlin Classification in 2012 defined three categories of ARDS according to hypoxemia (mild, moderate, and severe), and the term “acute lung injury” was assigned for general description or for animal models. ALI/ARDS can originate from direct lung triggers such as pneumonia or aspiration, or from extrapulmonary reasons such as sepsis or trauma. Despite growing understanding the ARDS pathophysiology, efficacy of standard treatments, such as lung protective ventilation, prone positioning, and neuromuscular blockers, is often limited. However, there is an increasing evidence that direct and indirect forms of ARDS may differ not only in the manifestations of alterations, but also in the response to treatment. Thus, individualized treatment according to ARDS subtypes may enhance the efficacy of given treatment and improve the survival of patients.

Mental disorders affect 10-20 % of the young population in the world. Major depressive disorder (MDD) is a common mental disease with a multifactorial and not clearly explained pathophysiology. Many cases remain undetected and untreated, which influences patients’ physical and mental health and their quality of life also in adulthood. The aim of our pilot study was to assess the prediction value of selected potential biomarkers, including blood cell counts, blood cell ratios, and parameters like peroxiredoxin 1 (PRDX1), tenascin C (TNC) and type IV collagen (COL4) between depressive pediatric patients and healthy peers and to evaluate a short effect of antidepressant treatment. In this study, 27 young depressive patients and 26 non-depressed age-matched controls were included. Blood analyses and immunological assays using commercial kits were performed. Platelet count was the only blood parameter for which the case/control status was statistically significant (p=0.01) in a regression model controlling for the age and gender differences. The results from ELISA analyses showed that the case/control status is a significant predictor of the parameters PRDX1 (p=0.05) and COL4 (p=0.009) in respective regression model considering the age and gender differences between MDD patients and controls. A major finding of this study is that values of platelet count, monocyte to lymphocyte ratio, white blood cell, and monocyte counts were assessed by the Random Forest machine learning algorithm as relevant predictors for discrimination between MDD patients and healthy controls with a power of prediction AUC=0.749.

Acute respiratory distress syndrome (ARDS) is characterized by diffuse lung damage, inflammation, oedema formation, and surfactant dysfunction leading to hypoxemia. Severe ARDS can accelerate the injury of other organs, worsening the patient´s status. There is an evidence that the lung tissue injury affects the right heart function causing cor pulmonale. However, heart tissue changes associated with ARDS are still poorly known. Therefore, this study evaluated oxidative and inflammatory modifications of the heart tissue in two experimental models of ARDS induced in New Zealand rabbits by intratracheal instillation of neonatal meconium (100 mg/kg) or by repetitive lung lavages with saline (30 ml/kg). Since induction of the respiratory insufficiency, all animals were oxygen-ventilated for next 5 h. Total and differential counts of leukocytes were measured in the arterial blood, markers of myocardial injury [(troponin, creatine kinase - myocardial band (CK-MB), lactate dehydrogenase (LD)] in the plasma, and markers of inflammation [tumour necrosis factor (TNF)α, interleukin (IL)-6], cardiovascular risk [galectin-3 (Gal-3)], oxidative changes [thiobarbituric acid reactive substances (TBARS), 3-nitrotyrosine (3NT)], and vascular damage [receptor for advanced glycation end products (RAGE)] in the heart tissue. Apoptosis of heart cells was investigated immunohistochemically. In both ARDS models, counts of total leukocytes and neutrophils in the blood, markers of myocardial injury, inflammation, oxidative and vascular damage in the plasma and heart tissue, and heart cell apoptosis increased compared to controls. This study indicates that changes associated with ARDS may contribute to early heart damage what can potentially deteriorate the cardiac function and contribute to its failure.

Acute damage to the lung may originate from various direct and indirect reasons. Direct lung injury may be caused by pneumonia, near-drowning, aspiration, inhalation of toxic gases etc., while indirect lung injury is secondary, following any severe extra-pulmonary disease, e.g. sepsis, acute pancreatitis, or severe trauma. Due to a complex pathophysiology of the acute lung injury, the treatment is also extremely complicated and except for lung-protective ventilation there have been no specific treatment approaches recommended. An urgent need for a reliable and sufficiently effective treatment forces the researchers into testing novel therapeutic strategies. However, most of these determinations should be done in the laboratory conditions using animals. Complex methods of preparation of various experimental models of the acute lung injury has gradually developed within decades. Nowadays, there have been the models of direct, indirect, or mixed lung injury well established, as well as the models evoked by a combination of two triggering factors. Although the applicability of the results from animal experiments to patients might be limited by many factors, animal models are essential for understanding the patho-physiology of acute lung injury and provide an exceptional opportunity to search for novel therapeutical strategies.

Asthma is a heterogenous disease which pathophysiology is still poorly understood. Asthma was traditionally divided into allergic (extrinsic) and non-allergic (intrinsic) types, while patients with allergic type responded better to corticosteroids. Since 2013 the definition of asthma has changed. Recently, better insight into clinical consi -derations and underlying inflammatory phenotypes has been gained. Defining these phenotypes has already led to more specific clinical trials and, therefore, to more personalized and successfully targeted therapy. For future, much more effort is put in identifying new phenotype-specific biomarkers which could be helpful in stratification of heterogeneous patients with asthma.

Acute respiratory distress syndrome (ARDS) is a common complication of critical illness characterized by lung inflammation, epithelial and endothelial dysfunction, alveolar-capillary leakage, and worsening respiratory failure. The present study aimed to investigate the anti-inflammatory effects of non-selective phosphodiesterase (PDE) inhibitor aminophylline. New Zealand white rabbits were randomly divided into 3 groups: animals with respiratory failure defined as PaO2/FiO2 ratio (P/F) below < 26.7 kPa, and induced by saline lung lavage (ARDS), animals with ARDS treated with intravenous aminophylline (1 mg/kg; ARDS/AMINO), and healthy ventilated controls (Control). All animals were oxygen ventilated for an additional 4 h and respiratory parameters were recorded regularly. Post mortem, the lung tissue was evaluated for oedema formation, markers of inflammation (tumor necrosis factor, TNFα, interleukin (IL)-1β, -6, -8, -10, -13, -18), markers of epithelial damage (receptor for advanced glycation end products, RAGE) and endothelial injury (sphingosine 1-phosphate, S1P), oxidative damage (thiobarbituric acid reactive substances, TBARS, 3-nitrotyrosine, 3NT, total antioxidant capacity, TAC). Aminophylline therapy decreased the levels of pro-inflammatory cytokines, markers of epithelial and endothelial injury, oxidative modifications in lung tissue, reduced lung oedema, and improved lung function parameters compared to untreated ARDS animals. In conclusion, non-selective PDE inhibitor aminophylline showed a significant anti-inflammatory activity suggesting a potential of this drug to be a valuable component of ARDS therapy.

Inhalation of silica particles causes inflammatory changes leading to fibrotizing silicosis. Considering a lack of effective therapy, and a growing information on the wide actions of green tea polyphenols, particularly epigallocatechin-3-gallate (EGCG), the aim of this study was to evaluate the early effects of EGCG on markers of inflammation and lung fibrosis in silicotic rats. The silicosis model was induced by a single transoral intratracheal instillation of silica (50 mg/mL/animal), while controls received an equivalent volume of saline. The treatment with intraperitoneal EGCG (20 mg/kg, or saline in controls) was initiated the next day after silica instillation and was given twice a week. Animals were euthanized 14 or 28 days after the treatment onset, and the total and differential counts of leukocytes in the blood and bronchoalveolar lavage fluid (BALF), wet/dry lung weight ratio, and markers of inflammation, oxidative stress, and fibrosis in the lung were determined. The presence of collagen and smooth muscle mass in the walls of bronchioles and lung vessels was investigated immunohistochemically. Early treatment with EGCG showed some potential to alleviate inflammation, and a trend to decrease oxidative stress-induced changes, including apoptosis, and a prevention of fibrotic changes in the bronchioles and pulmonary vessels. However, further investigations should be undertaken to elucidate the effects of EGCG in the lung silicosis model in more detail. In addition, because of insufficient data from EGCG delivery in silicosis, the positive and eventual adverse effects of this herbal compound should be carefully studied before any preventive use or therapy with EGCG may be recommended.

FeNO measurement is a validated non-invasive technique, which is used for diagnosis and monitoring of asthma. It would be desirable to find a reliable method to monitor allergic rhinitis (AR) via measurement of FeNO, and/or nasal nitric oxide (nNO). The aim of our study was the assessment of the efficacy of FeNO and nNO as markers in AR treatment. FeNO and nNO were measured with the portable NO analyser (NIOX MINO®) in healthy participants and in patients with AR. The patients were examined during the pollen season and out of it. The effect of local corticosteroids and antihistamine therapy was observed in patients with AR during pollen season after three weeks of therapy. There are significant differences between FeNO and nNO in patients with AR compared to healthy controls at all set points of measurements. While FeNO responded well to the treatment with both antihistamines and combined therapy, nNO decreased only after combined therapy with antihistamines and nasal corticosteroids. nNO monitoring alone is not a suitable method to monitor inflammation of the upper airways in AR and its suppression by anti-allergic treatment and should be correlated with other markers as FeNO or symptom scores.

Inflammation associated with acute respiratory distress syndrome (ARDS) can damage the alveolar epithelium and surfactant and worsen the respiratory failure. Glucocorticoids (GC) appear to be a rational therapeutic approach, but the effect is still unclear, especially for early administration and low-dose. In this study we compared two low doses of dexamethasone in early phase of surfactant-depleted model of acute respiratory distress syndrome (ARDS). In the study, lung-lavaged New Zealand rabbits with respiratory failure (PaO2

Inhalation of silica particles is an environmental and occupational cause of silicosis, a type of pneumoconiosis. Development of the lung silicosis is a unique process in which the vicious cycle of ingestion of inhaled silica particles by alveolar macrophages and their release triggers inflammation, generation of nodular lesions, and irreversible fibrosis. The pathophysiology of silicosis is complex, and interactions between the pathomechanisms have not been completely understood. However, elucidation of silica-induced inflammation cascades and inflammation-fibrosis relations has uncovered several novel possibilities of therapeutic targeting. This article reviews new information on the pathophysiology of silicosis and points out several promising treatment approaches targeting silicosis-related pathways.

The study aimed to prove the hypothesis that exogenous surfactant and an antibiotic polymyxin B (PxB) can more effectively reduce lipopolysaccharide (LPS)-induced acute lung injury (ALI) than surfactant treatment alone, and to evaluate the effect of this treatment on the gene expression of surfactant proteins (SPs). Anesthetized rats were intratracheally instilled with different doses of LPS to induce ALI. Animals with LPS 500 μg/kg have been treated with exogenous surfactant (poractant alfa, Curosurf®, 50 mg PL/kg b.w.) or surfactant with PxB 1% w.w. (PSUR + PxB) and mechanically ventilated for 5 hrs. LPS at 500 μg/kg increased lung edema, oxidative stress, and the levels of proinflammatory mediators in lung tissue and bronchoalveolar lavage fluid (BALF). PSUR reduced lung edema and oxidative stress in the lungs and IL-6 in BALF. This effect was further potentiated by PxB added to PSUR. Exogenous surfactant enhanced the gene expression of SP-A, SP-B, and SP-C, however, gene expression for all SPs was reduced after treatment with PSUR + PxB. In mechanically ventilated rats with LPS-induced ALI, the positive effect of exogenous surfactant on inflammation and oxidative stress was potentiated with PxB. Due to the tendency for reduced SPs gene expression after surfactant/PxB treatment topical use of PxB should be considered with caution.

In physiological conditions, neonatal airways are well-protected against aspiration of fluid or particulate material into the lungs, with laryngeal chemoreflex (LCR) being the most powerful mechanism. Failure of this protection allows substances to enter the lower airways, which starts a series of pathophysiological events initiated by inflammation and surfactant inactivation. The condition is defined as neonatal acute respiratory distress syndrome (ARDS), and its symptoms can range from mild respiratory distress to respiratory failure, often accompanied by persistent pulmonary hypertension (PPHN), in turn even leading to death. The management, therefore, may be very challenging. Areas covered: This review covers protection mechanisms of the neonatal lower airways, the etiology, and pathophysiology of neonatal aspiration syndrome (NAS), its definition in view of current literature, possible treatment options, and future trends. Expert commentary: Inflammation and secondary surfactant deficiency stand in the foreground of neonatal aspiration. Management focuses mainly on appropriate oxygenation, ventilation, improvement in PPHN, and maintenance of systemic circulation, which is largely symptomatic and supportive. Future research is required to evaluate the justification of using exogenous surfactants, antibiotics, anti-inflammatory and antioxidative drugs, or their combinations.

Damage of alveolar-capillary barrier, inflammation, oxidative injury, and lung cell apoptosis represent the key features of acute lung injury (ALI). This study evaluated if selective phosphodiesterase (PDE)-4 inhibitor roflumilast can reduce the mentioned changes in lavage-induced model of ALI. Rabbits with ALI were divided into 2 groups: ALI without therapy (A group) and ALI treated with roflumilast i.v. (1 mg/kg; A+R group). One group of healthy animals without ALI served as ventilated controls (C group). All animals were oxygen-ventilated for further 4 h. At the end of experiment, total and differential counts of cells in bronchoalveolar lavage fluid (BALF) and total and differential counts of white blood cells were estimated. Lung edema formation was assessed from determination of protein content in BALF. Pro-inflammatory cytokines (TNFα, IL-6 and IL-8) and markers of oxidation (3-nitrotyrosine, thiobarbituric-acid reactive substances) were detected in the lung tissue and plasma. Apoptosis of lung cells was investigated immunohistochemically. Treatment with roflumilast reduced leak of cells, particularly of neutrophils, into the lung, decreased concentrations of cytokines and oxidative products in the lung and plasma, and reduced lung cell apoptosis and edema formation. Concluding, PDE4 inhibitor roflumilast showed potent anti-inflammatory actions in this model of ALI.

A group of 11 enzyme families of metalophosphohydrolases called phosphodiesterases (PDEs) is responsible for a hydrolysis of intracellular cAMP and cGMP. Xanthine derivatives (methylxanthines) inhibit PDEs without selective action on their single isoforms and lead to many pharmacological effects, e.g. bronchodilation, anti-inflammatory and immunomodulating effects, and thus they can modulate the cough reflex. Contrary, selective PDE inhibitors have been developed to inhibit PDE isoforms with different pharmacological effects based on their tissue expression. In this paper, effects of non-selective PDE inhibitors (e.g. theophylline) are discussed, with a description of other putative mechanisms in their effects on cough. Antitussive effects of selective inhibitors of several PDE isoforms are reviewed, focusing on PDE1, PDE3, PDE4, PDE5 and PDE7. The inhibition of PDEs suggests participation of bronchodilation, suppression of TRPV channels and anti-inflammatory action in cough suppression. Selective PDE3, PDE4 and PDE5 inhibitors have demonstrated the most significant cough suppressive effects, confirming their benefits in chronic inflammatory airway diseases associated with bronchoconstriction and cough.

Phosphodiesterases (PDEs) are a superfamily of enzymes that catalyze the hydrolysis of phosphodiester bonds of 3',5' cyclic adenosine and guanosine monophosphate (cAMP and cGMP). PDEs control hydrolysis of cyclic nucleotides in many cells and tissues. Inhibition of PDEs by selective or nonselective PDE inhibitors represents an effective targeted strategy for the treatment of various diseases including respiratory disorders. Recent data have demonstrated that PDE inhibitors can also be of benefit in respiratory distress in neonates. This article outlines the pharmacological properties of nonselective and selective PDE inhibitors and provides up-to-date information regarding their use in experimental models of neonatal respiratory distress as well as in clinical studies.

Aims Combination of exogenous surfactant with antioxidant enzyme recombinant human superoxide dismutase (rhSOD) was tested in the treatment of experimental meconium aspiration syndrome as oxidative processes play key role in its pathogenesis. Material and methods Young New Zealand rabbits were instilled by saline (Sal group) or by meconium suspension (Mec group). Some of meconium-instilled animals were treated by surfactant alone (Surf group) or surfactant in combination with rhSOD (Surf + SOD group) and oxygen-ventilated for 5 h. PaO2/FiO2, oxygenation index, oxygen saturation, PaCO2, ventilation efficiency index and alveolar-arterial gradient were evaluated every hour; post mortem, cells in bronchoalveolar lavage were counted, inflammatory and oxidative markers were assessed using ELISA in lung tissue homogenates. Key findings Exogenous surfactant combined with rhSOD improved oxygenation during the first hour after the treatment more than surfactant alone (p = 0.039 to 0.0001 vs. Mec and Surf group). Amelioration was also seen in CO2 elimination (p = 0.049 to 0.0096 vs. Mec group), alveolar-arterial gradient diminution (p = 0.024 to 0.0019 vs. Mec and Surf group), prevention of oxidative damage and cytokine production (p = 0.049 to 0.002 vs. Mec group). Significance It seems that inhibition of oxidative signalization may be strong supporting factor in surfactant treatment of MAS.

Meconium aspiration syndrome (MAS) is life-threatening respiratory failure of newborns which can be treated by exogenous surfactant. In response to meconium, increased levels of chemokine IL-8 (CXCL8) stimulate massive neutrophil infiltration of the lungs. Local accumulation and activation of neutrophils, on-going inflammation, lung edema, and oxidative damage contribute to inactivation of endogenous and therapeutically given surfactants. Therefore, we have hypothesized that addition of monoclonal anti-IL-8 antibody into exogenous surfactant can mitigate the neutrophil-induced local injury and the secondary surfactant inactivation and may finally result in improvement of respiratory functions.New Zealand rabbits with intratracheal meconium-induced respiratory failure (meconium 25 mg/ml, 4 ml/kg) were divided into three groups: untreated (M), surfactant-treated (M + S), and treated with combination of surfactant and anti-IL-8 antibody (M + S + anti-IL-8). Surfactant therapy consisted of two lung lavages with diluted porcine surfactant Curosurf (10 ml/kg, 5 mg phospholipids (PL)/ml) followed by undiluted Curosurf (100 mg PL/kg) delivered by means of asymmetric high-frequency jet ventilation (f. 300/min, Ti 20%). In M + S + anti-IL-8 group, anti-IL-8 antibody (100 µg/kg) was added directly to Curosurf dose. Animals were oxygen-ventilated for additional 5 h, respiratory parameters were measured regularly. Subsequently, cell counts in bronchoalveolar lavage fluid (BAL), lung edema formation, oxidative damage, levels of interleukins (IL)-1β and IL-6 in the lung homogenate were evaluated.Surfactant instillation significantly improved lung function. Addition of anti-IL-8 to surfactant further improved gas exchange and ventilation efficiency and had longer-lasting effect than surfactant-only therapy. Combined treatment showed the trend to reduce neutrophil count in BAL fluid, local oxidative damage, and levels of IL-1β and IL-6 more effectively than surfactant-alone, however, these differences were not significant.Addition of anti-IL-8 antibody to surfactant could potentiate the efficacy of Curosurf on the gas exchange in experimental model of MAS.

This study aimed to investigate whether a selective phosphodiesterase-3 (PDE3) inhibitor olprinone can positively influence the inflammation, apoptosis, and respiratory parameters in animals with acute respiratory distress syndrome (ARDS) model induced by repetitive saline lung lavage. Adult rabbits were divided into 3 groups: ARDS without therapy (ARDS), ARDS treated with olprinone i.v. (1 mg/kg, ARDS/PDE3), and healthy ventilated controls (Control), and were oxygen-ventilated for the following 4 h. Dynamic lung&ndash, thorax compliance (Cdyn), mean airway pressure (MAP), arterial oxygen saturation (SaO2), alveolar-arterial gradient (AAG), ratio between partial pressure of oxygen in arterial blood to a fraction of inspired oxygen (PaO2/FiO2), oxygenation index (OI), and ventilation efficiency index (VEI) were evaluated every hour. Post mortem, inflammatory and oxidative markers (interleukin (IL)-6, IL-1&beta, a receptor for advanced glycation end products (RAGE), IL-10, total antioxidant capacity (TAC), 3-nitrotyrosine (3NT), and malondialdehyde (MDA) and apoptosis (apoptotic index and caspase-3) were assessed in the lung tissue. Treatment with olprinone reduced the release of inflammatory mediators and markers of oxidative damage decreased apoptosis of epithelial cells and improved respiratory parameters. The results indicate a future potential of PDE3 inhibitors also in the therapy of ARDS.

Acute respiratory distress syndrome (ARDS) is characterized by acute hypoxemia, neutrophil-mediated inflammation, and lung edema formation. Whereas lung damage might be alleviated by nitric oxide (NO), goal of this study was to evaluate if intratracheal NO donor S-nitroso-N-acetylpenicillamine (SNAP) can positively influence the lung functions in experimental model of ARDS. New Zealand rabbits with respiratory failure induced by saline lavage (30 ml/kg, 9±3 times) were divided into: ARDS group without therapy, ARDS group treated with SNAP (7 mg/kg i.t.), and healthy Control group. During 5 h of ventilation, respiratory parameters (blood gases, ventilatory pressures) were estimated. After anesthetics overdosing, left lung was saline-lavaged and cell count, cell viability and protein content in bronchoalveolar lavage fluid (BALF) were measured. Right lung tissue was used for estimation of wet/dry weight ratio, concentration of NO metabolites, and histomorphological investigation. Repetitive lung lavage induced lung injury, worsened gas exchange, and damaged alveolar-capillary membrane. Administration of SNAP reduced cell count in BALF, lung edema formation, NO metabolites, and histopathological signs of injury, and improved respiratory parameters. Treatment with intratracheal SNAP alleviated lung injury and edema and improved lung functions in a saline-lavaged model of ARDS suggesting a potential of NO donors also for patients with ARDS.

Pulmonary surfactant has a relaxing effect on the airway smooth muscle (ASM), which suggests its role in the pathogenesis of respiratory diseases associated with hyperreactivity of the ASM, such as asthma and chronic obstructive pulmonary disease (COPD). The ASM tone may be directly or indirectly modified by bacterial wall component lipopolysaccharide (LPS). This study elucidated the effect of LPS on the ASM reactivity and the role of surfactant in this interaction. The experiments were performed using ASM of adult guinea pigs by in vitro method of tissue organ bath (ASM unexposed-healthy or exposed to LPS under in vitro conditions) and ASM of animals intraperitoneally injected with LPS at a dose 1 mg/kg of b.w. once a day during 4-day period. Variable response of LPS was controlled by cyclooxygenase inhibitor indomethacin and relaxing effect of exogenous surfactant was studied using leukotriene and histamine receptor antagonists. The exogenous surfactant has relaxing effect on the ASM, but does not reverse LPS-induced smooth muscle contraction. The results further indicate participation of prostanoids and potential involvement of leukotriene and histamine H1 receptors in the airway smooth muscle contraction during LPS exposure.

Overproduction of oxidants within the lung leads to acute lung injury (ALI) which may progress to irreversible lung fibrosis. The sources of oxidants may be (1) intrinsic, that is, derived from phagocytic macrophages and neutrophils and endothelial and alveolar epithelial cells, or (2) extrinsic, that is, caused by inhaled pollutants or high concentrations of oxygen. The complex antioxidant system of the body includes reduction–oxidation enzymatic systems, nonenzymatic scavengers, and dietary components which balance the concentrations of both antioxidant and oxidant substances with dominance of a reducing state. However, decreasing levels of antioxidants and/or increasing levels of oxidants disturb the stability of the antioxidant–oxidant system and lead to oxidative lung injury. Several groups of therapeutic agents, including N-acetylcysteine, flavonoids, corticosteroids, phosphodiesterase inhibitors, etc., appeared to be beneficial in the treatment of various forms of experimentally induced ALI where they significantly reduced the oxidative damage. This chapter reviews the pathophysiology and mechanisms of ALI with respect to oxidative and inflammatory changes and critically evaluates perspectives of promising treatments to prevent or to minimize the oxidative changes in experimental models of ALI reflecting possibilities of their use also in the treatment of patients with acutely damaged lung.

Acute lung injury (ALI) is characterized by diffuse alveolar damage, inflammation, and transmigration and activation of inflammatory cells. This study evaluated if intravenous dexamethasone can influence lung inflammation and apoptosis in lavage-induced ALI. ALI was induced in rabbits by repetitive saline lung lavage (30 ml/kg, 9±3-times). Animals were divided into 3 groups: ALI without therapy (ALI), ALI treated with dexamethasone i.v. (0.5 mg/kg, Dexamed; ALI+DEX), and healthy non-ventilated controls (Control). After following 5 h of ventilation, ALI animals were overdosed by anesthetics. Total and differential counts of cells in bronchoalveolar lavage fluid (BAL) were estimated. Lung edema was expressed as wet/dry weight ratio. Concentrations of IL-1ß, IL-8, esRAGE, S1PR3 in the lung were analyzed by ELISA methods. In right lung, apoptotic cells were evaluated by TUNEL assay and caspase-3 immunohistochemically. Dexamethasone showed a trend to improve lung functions and histopathological changes, reduced leak of neutrophils (P

Severe meconium aspiration syndrome (MAS) in the neonates often requires a ventilatory support. As a method of choice, a conventional mechanical ventilation with small tidal volumes (VTIn the young rabbits, a model of MAS was induced by an intratracheal instillation of a suspension of neonatal meconium (4 ml/kg, 25 mg/ml). After creating the model of MAS, the animals were ventilated with small-volume CMV (frequency 50/min, VTMeconium instillation seriously worsened the gas exchange and induced inflammation and lung edema formation. In the Aura group, slightly lower concentrations of cytokines were found and better gas exchange early after creating the MAS model was observed. However, there were no significant differences in the respiratory parameters between the ventilated groups at the end of experiment (P>0.05).Concluding, the newly developed neonatal version of the ventilator Aura V was found to be fully comparable to widely used neonatal ventilator SLE5000. Results provided by Aura V in CMV ventilation of rabbits with meconium-induced acute lung injury suggest its great potential also for future clinical use, i.e. for ventilation of the neonates with MAS.

Despite progress in understanding the pathophysiology of acute lung damage, currently approved treatment possibilities are limited to lung-protective ventilation, prone positioning, and supportive interventions. Various pharmacological approaches have also been tested, with neuromuscular blockers and corticosteroids considered as the most promising. However, inhibitors of phosphodiesterases (PDEs) also exert a broad spectrum of favorable effects potentially beneficial in acute lung damage. This article reviews pharmacological action and therapeutical potential of nonselective and selective PDE inhibitors and summarizes the results from available studies focused on the use of PDE inhibitors in animal models and clinical studies, including their adverse effects. The data suggest that xanthines as representatives of nonselective PDE inhibitors may reduce acute lung damage, and decrease mortality and length of hospital stay. Various (selective) PDE3, PDE4, and PDE5 inhibitors have also demonstrated stabilization of the pulmonary epithelial–endothelial barrier and reduction the sepsis- and inflammation-increased microvascular permeability, and suppression of the production of inflammatory mediators, which finally resulted in improved oxygenation and ventilatory parameters. However, the current lack of sufficient clinical evidence limits their recommendation for a broader use. A separate chapter focuses on involvement of cyclic adenosine monophosphate (cAMP) and PDE-related changes in its metabolism in association with coronavirus disease 2019 (COVID-19). The chapter illuminates perspectives of the use of PDE inhibitors as an add-on treatment based on actual experimental and clinical trials with preliminary data suggesting their potential benefit.

A simple, highly sensitive and rapid method for quantification of olprinone (phosphodiesterase 3 inhibitor) in rabbit plasma using liquid chromatography-tandem mass spectrometry with electrospray was developed. An aliquot of 50 μL of plasma sample was cleaned up and extracted using Ostro™ 96-well plate followed by dilution. Chromatographic separation of olprinone and olprinone-d3 was carried out on a CORTECS® T3 column within 3 min. Detection was achieved using a triple quadrupole mass spectrometer employing electrospray ionization operated in positive ion multiple reaction monitoring mode using the transitions m/z 251.07 → m/z 155.06 and m/z 254.21 → m/z 158.10 for olprinone and olprinone-d3, respectively. The method was validated according to US Food and Drug Administration guideline for bioanalytical methods, and showed excellent linearity in the range 10.0-2000.0 ng/mL with coefficient of determination >0.99. The intra- and inter-day precisions (CV) were

Introduction: Acute lung injury (ALI) is a disorder characterised by a neutrophil-mediated inflammation, lung edema, and hypoxia. Phosphodiesterase (PDE)-4 is mainly expressed in inflammatory cells, its inhibition reduce action of inflammatory cells. Aim of the study: The study evaluated if systemic administration of PDE-4 inhibitor roflumilast influences inflammation, oxidative stress and apoptosis in ALI. Methods: Rabbits with lavage-induced respiratory failure were divided into: animals with ALI model (A), animals with ALI treated with roflumilast (A+R, 1 mg/kg i.v.):), healthy ventilated controls (C). After 4 hours of ventilation, total and differential counts of cells in bronchoalveolar lavage fluid were measured. Concentrations of thiobarbituric acid-reactive substances (TBARS), 3-nitrotyrosine (3NT), interleukins (IL)-6, -8, and TNF-α in the lung tissue were analysed. Lung edema formation was expressed as wet-dry lung weight ratio. In lung tissue, apoptotic cells were evaluated by TUNEL assay and caspase-3 immunohistochemically. Results: Roflumilast therapy reduced migration of neutrophils into the lungs. PDE4 inhibition decreased the release of pro-inflammatory cytokines (IL-6, -8, TNF-α), markers of oxidative stress (TBARS, 3NT), apoptosis (apoptotic index, caspase-3) in the lung tissue compared to ALI group. Conclusion: Inhibition of PDE4 in the model of ALI mitigated the release of cytokines and chemokines from inflammatory cells and production of reactive oxygen species suggesting potential perspectives of PDE4 inhibitors in the treatment of ALI. Grants: APVV-0435-11, APVV-15-0075, VEGA 1/0356/18, BioMed (ITMS 26220220187).

The efficacy of H4R antagonist JNJ7777120 on nasal symptoms, cough, airway resistance (Raw), inflammatory cell count in bronchoalveolar lavage (BAL) and blood in ovalbumin (OVA) induced allergic rhinitis (AR) was studied in guinea pigs. Animals (n=8) were sensitized by i.p. OVA and were repeatedly challenged with nasal OVA to induce rhinitis, seven animals were not sensitized. Animals were pre-treated with JNJ7777120 2.5 and 5mg/kg i.p. 30 min prior OVA. Cough was induced by inhalation of citric acid, Raw was measured in vivo by Pennock's method as baseline, during AR and after JNJ7777120 treatment. Leucocyte count in BAL and blood was analyzed. JNJ7777120 (5mg/kg) significantly suppressed nasal symptoms and the number of coughs. This compound significantly inhibited airway reactivity to histamine, but not methacholine. Pre-treatment with JNJ7777120 5mg/kg did not influence significantly the leucocyte count in BAL and blood except for a significant decrease in monocyte count in blood compared to the control group (p

Acute respiratory distress syndrome (ARDS) and its milder form acute lung injury (ALI) may result from various diseases and situations including sepsis, pneumonia, trauma, acute pancreatitis, aspiration of gastric contents, near-drowning etc. ALI/ARDS is characterized by diffuse alveolar injury, lung edema formation, neutrophil-derived inflammation, and surfactant dysfunction. Clinically, ALI/ARDS is manifested by decreased lung compliance, severe hypoxemia, and bilateral pulmonary infiltrates. Severity and further characteristics of ALI/ARDS may be detected by biomarkers in the plasma and bronchoalveolar lavage fluid (or tracheal aspirate) of patients. Changed concentrations of individual markers may suggest injury or activation of the specific types of lung cells-epithelial or endothelial cells, neutrophils, macrophages, etc.), and thereby help in diagnostics and in evaluation of the patient's clinical status and the treatment efficacy. This chapter reviews various biomarkers of acute lung injury and evaluates their usefulness in diagnostics and prognostication of ALI/ARDS.

Introduction Chronic obstructive diseases of airways associated with cough and/or airway smooth muscle hyperresponsiveness are usually treated with bronchodilating and anti-inflammatory drugs. Recently, selective phosphodiesterase (PDE) 4 inhibitors have been introduced into the therapy of chronic obstructive pulmonary disease. Several studies have demonstrated their ability to influence the airway reactivity and eosinophilic inflammation by increasing the intracellular cAMP concentrations also in bronchial asthma. Furthermore, the expression of PDE5 in several immune cells suggests perspectives of PDE5 inhibitors in the therapy of inflammation, as well. Purpose The aim of this study was to assess the dose-dependent effects of PDE4 and PDE5 inhibitors in allergic inflammation. Therefore, the effects of 7-days administration of PDE4 inhibitor roflumilast and PDE5 inhibitor tadalafil at two different doses in experimentally-induced allergic inflammation were evaluated. Materials and methods In the study, male adult guinea pigs were used. Control group was non-sensitized. Other animals were sensitized with ovalbumin over two weeks and thereafter treated intraperitoneally for 7 days with roflumilast or tadalafil (daily dose 0.5 mg/kg or 1.0 mg/kg b.w.), or with vehicle. Results Both roflumilast and tadalafil reduced specific airway resistance after nebulization of histamine (marker of in vivo airway reactivity) at both doses used. The in vitro airway reactivity to cumulative doses of acetylcholine was significantly reduced for roflumilast at higher dose, predominantly in the lung tissue strips. Histamine-induced contractile responses were significantly influenced in both lung and tracheal tissue strips, predominantly at the higher doses. Tadalafil led to a decrease in contractile responses induced by both acetylcholine and histamine, with more significant effects in the lung tissue strips. These changes were associated with decreased numbers of circulating leukocytes and eosinophils and concentrations of interleukin (IL)-4, IL-5 and TNF-α in the lung homogenate. Conclusions The selective PDE4 and PDE5 inhibitors alleviated allergic airway inflammation, with more significant effects at the higher doses.

Bronchial asthma is one of the most common, chronic respiratory diseases, characterized by reversible airway obstruction, eosinophil and Th2 infiltration, airway hyperresponsiveness and airway remodelling; with many cells and mediators involved. Metabolomics is a relatively new field in “omics” sciences enabling the identification of metabolome for better diagnostics and studying of diseases phenotype. The aim of this study was to investigate the role of targeted metabolomics study for better understanding of the bronchial asthma pathophysiology and finding potential biomarkers in experimental models of eosinophilic inflammation. Plasma level of 185 metabolites was measured with the AbsoluteIDQ™ p180 kit in guinea pigs with experimentally-induced allergic inflammation (n = 15) compared to naive non-sensitised and non-challenged controls (n = 18). Of the 185 metabolites identified in plasma, 22 were significantly different and changed in ovalbumin sensitised animals. Plasma level of 13 phosphatidylcholines with saturated and unsaturated long-chain fatty acids, total phosphatidylcholines count, carnitine, symmetric dimethylarginine and its ratio to total unmodified arginine, and kynurenine to tryptophan ratio were found to be decreased, while phospholipase A2 activity indicator, tryptophan, taurine and ratio of methionine sulfoxide to unmodified methionine were found to be increased in sensitised guinea pigs compared to naive controls. Targeted metabolomic analysis revealed significant differences in plasma metabolome of sensitised guinea pigs. Our observations point to the activation of inflammatory and immune pathways, as well as the involvement of oxidative stress.

Meconium aspiration syndrome (MAS) is meconium-induced respiratory failure of newborns associated with activation of inflammatory and oxidative pathways. For severe MAS, exogenous surfactant treatment is used which improves respiratory functions but does not treat the inflammation. Oxidative process can lead to later surfactant inactivation; hence, surfactant combination with antioxidative agent may enhance the therapeutic effect. Young New Zealand rabbits were instilled by meconium suspension and treated by surfactant alone, N-acetylcysteine (NAC) alone or by their combination and oxygen-ventilated for 5 h. Blood samples were taken before and 30 min after meconium application and 30 min, 1, 3 and 5 h after the treatment for evaluating of oxidative damage, total leukocyte count, leukocyte differential count and respiratory parameters. Leukocyte differential was assessed also in bronchoalveolar lavage fluid. NAC alone had only mild therapeutic effect on MAS. However, the combination of NAC and surfactant facilitated rapid onset of therapeutic effect in respiratory parameters (oxygenation index, PaO2/FiO2) compared to surfactant alone and was the only treatment which prevented neutrophil migration into the lungs, oxidative damage and lung edema. Moreover, NAC suppressed IL-8 and IL-β formation and thus seems to be favorable agent for improving surfactant therapy in MAS.

In severe respiratory insufficiency, neonatal and pediatric patients should be ventilated artificially by a ventilator. Aim of this experimental study was to evaluate whether the newly developed ventilator Chirana Aura V may effectively ventilate the lungs of animals with two different models of acute lung injury: acute respiratory distress syndrome (ARDS) induced by repetitive saline lavage and meconium aspiration syndrome (MAS) induced by intratracheal instillation of neonatal meconium. The experiments were performed on 10 adult rabbits (New Zealand white). In ARDS group (n=5), the lungs were repetitively lavaged with saline (30 ml/kg) until partial pressure of oxygen (PaO2) in arterial blood was under 26.7 kPa at inspiratory fraction of oxygen FiO2=1.0. In MAS group (n=5), animals were instilled 4 ml/kg of suspension of human meconium (25 mg/ml). When the model of acute lung injury was developed, animals were ventilated for additional 2 hours with pressure control ventilation (PCV) regime by ventilator Chirana Aura V. Ventilatory parameters, blood gases, acid-base balance, end-tidal CO2, O2 saturation of hemoglobin, oxygenation indexes, ventilation efficiency index, dynamic lung compliance, and right-to-left pulmonary shunts were measured and calculated in regular time intervals. In both experimental groups, used ventilatory settings provided acceptable gas exchange within the period of observation. Thus, the results indicate that ventilator Chirana Aura V might be suitable for ventilation of animal models of acute lung injury. However, further pre-clinical investigation is needed before its use may be recommended in neonatal and/or pediatric patients with acute lung injury.

Acute lung injury (ALI) represents a serious heterogenous pulmonary disorder with high mortality. Despite improved understanding of the pathophysiology, the efficacy of standard therapies such as lung-protective mechanical ventilation, prone positioning and administration of neuromuscular blocking agents is limited. Recent studies have shown some benefits of corticosteroids (CS). Prolonged use of CS can shorten duration of mechanical ventilation, duration of hospitalization or improve oxygenation, probably because of a wide spectrum of potentially desired actions including anti-inflammatory, antioxidant, pulmonary vasodilator and anti-oedematous effects. However, the results from experimental vs. clinical studies as well as among the clinical trials are often controversial, probably due to differences in the designs of the trials. Thus, before the use of CS in ARDS can be definitively confirmed or refused, the additional studies should be carried on to determine the most appropriate dosing, timing and choice of CS and to analyse the potential risks of CS administration in various groups of patients with ARDS.

The autonomic nervous system, in particular vagal function, plays an important role in a wide range of somatic and mental disorders. Cardiac vagal function can be indexed by the respiratory sinus arrhythmia (RSA) - oscillations in heart rate linked to respiration mediated predominantly by fluctuations of vagus nerve efferent traffic originating in the nucleus ambiguus. Moreover, the neurocardiac vagal modulation has been shown to be related to physiological adaptability/flexibity and emotional regulation. Thus, greater vagal withdrawal during stressors and subsequent recovery should be indicative of a more flexible physiological response system. Importantly, the vagal inhibitory function plays a key role in the regulation of allostatic processes including the immune response (cholinergic anti-inflammatory pathway). Decreased cardiovagal function (lower RSA) was shown to be associated with increased proinflammatory markers and acute-phase proteins indicating increased allostatic load and poor health. Thus, the study of the vagal-immune interactions could help illuminate the pathway via which psychosocial factors may influence health and disease.