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Phosphodiesterases (PDEs) are known as a super-family of 11 isoenzymes, which can exert various functions based on their organ distribution. Aside from non-selective PDE inhibitors (methylxanthines, e.g. theophylline) used many years in clinical settings, increasing attention is focused on the involvement of selective PDE inhibitors in therapy of obstructive airway diseases associated with chronic inflammation. There are mostly PDE3, PDE4, and PDE7 isoforms present in the respiratory system. This paper describes the mechanisms of action, adverse effects, and potential clinical use of both non-selective and selective PDE inhibitors. The focus of the review is on the influence of PDE inhibitors on the immune system.

Normobaric hyperoxia is applied for the treatment of a wide variety of diseases and clinical conditions related to ischemia or hypoxia, but it can increase the risk of tissue damage and its efficiency is controversial. In the present study, we analyzed cardiac mitochondrial proteome derived from guinea pigs after 60 h exposure to 100% molecular oxygen (NBO) or O2 enriched with oxygen cation (NBO+). Two-dimensional gel electrophoresis followed by MALDI-TOF/TOF mass spectrometry identified twenty-two different proteins (among them ten nonmitochondrial) that were overexpressed in NBO and/or NBO+ group. Identified proteins were mainly involved in cellular energy metabolism (tricarboxylic acid cycle, oxidative phosphorylation, glycolysis), cardioprotection against stress, control of mitochondrial function, muscle contraction, and oxygen transport. These findings support the viewpoint that hyperoxia is associated with cellular stress and suggest complex adaptive responses which probably contribute to maintain or improve intracellular ATP levels and contractile function of cardiomyocytes. In addition, the results suggest that hyperoxia-induced cellular stress may be partially attenuated by utilization of NBO+ treatment.

Introduction: Phosphodiesterases (PDEs) are enzymes involved in degradation of cAMP and cGMP. The clinical effectiveness of selective PDE4 inhibitors has been confirmed previously in chronic obstructive pulmonary disease associated with neutrophil inflammation. The aim of this study was to evaluate effects of roflumilast (selective PDE4 inhibitor) and tadalafil (selective PDE5 inhibitor) on in vivo and in vitro airway smooth muscle reactivity to histamine, changes in blood cells count in blood and bronchoalveolar lavage fluid, and some inflammatory mediators (IL-4 and IL-5) in ovalbumin sensitized guinea pigs with experimentally induced eosinophil inflammation. Sensitized animals were exposed to aerosol of roflumilast, tadalafil, or both for 3 minutes once daily for 7 days. Sensitization with ovalbumin led to a significant increase in in vivo and in vitro airway reactivity. Similarly, increased plasmatic levels of IL-4, and IL-5 in blood were observed, with significant increase in differential counts of eosinophils both in blood and BAL fluid. The administration of roflumilast and tadalafil suppressed significantly in vivo airway reactivity, in vitro airway reactivity in tracheal tissue strips, and IL-4 and IL-5 levels, suggesting that PDE4 and PDE5 inhibition has potent anti-inflammatory effects in guinea pigs with ovalbumin induced eosinophil inflammation. This work was supported by the project „Biomedical Center Martin“ ITMS code: 26220220187, the project is co-financed from EU sources, and by VEGA grant 1/0260/14, Slovak Research and Development Agency under the contract No. APVV-0305-12, by Grant MZ2012/35-UKMA-12.

The aim of the study was to test the hypothesis that control of breathing via Hering–Breuer reflex (HB) is influenced by lipopolysaccharide (LPS)-induced fever in rats. Animals were injected intraperitoneally with LPS and control group with an equivalent volume of saline. HB reflex was elicited by inflations of the lungs followed by occlusion of the airways under control of esophageal pressure. Duration of HB reflex (Tapnoe) was continuously reduced as body temperature rose during experiment. Compared to normothermic controls, animals with fever had significant shortening of Tapnoe at 240 min and 300 min after LPS administration. Fever was further accompanied by a reduction in the strength of HB reflex (inhibitory ratio, IR). In comparison with controls, significant decrease of IR was observed at 300 min after LPS injection. Conclusion: altered neural control of breathing demonstrated by decreased power of Hering–Breuer inflation reflex in conditions of LPS-induced fever may facilitate thermal tachypnoea and/or play a role in the origin of respiratory instability accompanying febrile response.

Changes in Several Inflammatory and Oxidation Markers after Ovalbumin-Sensitization in a Guinea Pig Model of Allergic Asthma - A Pilot StudyOvalbumin (OVA)-sensitization is a common way to evoke changes similar to changes in allergic asthma in humans. Activated cells produce various pro-inflammatory and vasoactive substances including reactive oxygen species. The goal of this pilot study was to evaluate mobilization of leukocytes into the lungs and oxidation processes induced by OVA-sensitization in a guinea-pig model of allergic asthma. Guinea-pigs were divided into OVA-sensitized and naïve animals. After sacrificing animals, blood samples were taken and total and differential leukocyte counts were calculated, and eosinophil cationic protein (ECP) and total antioxidant status (TAS) in the plasma were determined. Left lungs were saline-lavaged and total number of cells and differential leukocyte count in the bronchoalveolar lavage fluid (BAL) were calculated. Right lung tissue was homogenized, ECP, TAS and products of lipid and protein oxidation (thiobarbituric acid-reactive substances and lysine-lipoperoxidation end-products) were determined in the lung homogenate. OVA-sensitization increased a total number of cells and percentages of eosinophils and neutrophils and slightly increased ECP in the blood and in the BAL fluid. In addition, increased lipid and protein oxidation in the lung homogenate, and decreased TAS in the plasma was found in OVA-sensitized compared to naïve animals. In conclusion, OVA-sensitization increased mobilization of leukocytes into the lungs and elevated production of reactive oxygen spesies (ROS), accompanied by a decrease in plasma TAS.

Selective Inhibition of Phosphodiesterase 7 (PDE7) by BRL50481 in Healthy and Ovalbumin-Sensitized Guinea Pigs Phosphodiesterase (PDE) inhibitors may have significant clinical benefit in respiratory diseases associated with inflammation. The aim was to evaluate effects of selective PDE7 inhibitor (BRL50481) on citric acid induced cough, in vivo and in vitro airway smooth muscle reactivity in both healthy and ovalbumin sensitized guinea pigs, as well as its effectiveness in changes of blood cells count. Tested drugs were administered intraperitoneally to male guinea pigs once daily for 7 days either vehicle 10% DMSO (dimethyl sulfoxide) 3 ml/kg (as control) or BRL50481 1 mg/kg. Double chamber whole body plethysmograph was used for evaluation of citric acid (0.6 M) induced cough and specific airway resistance. Organ bath method was used for measurement of tracheal and lung tissue strips contractions evoked by cumulative doses (10-8 - 10-3 mol/L) of acetylcholine (ACH) and histamine (HIS). In healthy guinea pigs we did not observe significant effect of tested drug BRL50481 on in vitro contractions (similarly to in vivo conditions). The effect on cough was in healthy animals negligible. In ovalbumin-sensitized animals, more pronounced in vitro relaxing effect of BRL50481 in HIS induced contractions was observed with similar results in vivo and no significant change in number of cough efforts. Our results suggest that PDE7 inhibitors have stronger anti-inflammatory effect compared to its direct effect on smooth muscle and cough.

Normobaric hyperoxia (NBO) is applied for treatment of various clinical conditions related to hypoxia, but it can potentially also induce generation of reactive oxygen species, causing cellular damage. In this study, we examined the effects of 60 h NBO treatment on lipid and protein oxidative damage and activity of superoxide dismutase (Mn-SOD) in brain mitochondria of guinea pigs. Despite significant stimulation of Mn-SOD expression and activity the NBO treatment resulted in accumulation of markers of oxidative lesions, including lipid peroxidation (conjugated dienes, thiobarbituric acid reactive substances) and protein modification (bityrosines, adducts with lipid peroxidation products, oxidized thiols). When inhaled O2 was enriched with oxygen cation, O 2 •+ , the Mn-SOD expression and activity were stimulated to similar extend, but lipid peroxidation and protein oxidation were prevented. These results suggest that long-term NBO treatment causes oxidative stress, but enrichment of inhaled oxygen by oxygen cation can protect the brain again adverse effects of hyperoxia.

Evaluation of Surfactant Function: In Vitro and In Vivo Techniques in Experimental Respirology Pulmonary surfactant is present as the thin film of surface active material in the terminal airspaces and conducting airways. The major function of the surfactant film is to reduce the surface tension at the alveolar surface. Deficiency or dysfunction of pulmonary surfactant cause severe respiratory diseases that make the study of pulmonary surfactant not only of physiological but also of clinical importance. There are three main categories of methods for assessing the properties of pulmonary surfactant: in vitro, in situ and in vivo techniques. Pulsating bubble surfactometer (PBS) and captive bubble surfactometer (CBS) enables to study surfactant properties at spherical air-liquid interphase. Capillary surfactometer in contrast to alveolar models mimics the human terminal airways and evaluates surface properties required for airway patency. Each of above-mentioned methods enables to study exogenous surfactants, as well as surface activity of lavage fluids or tracheal aspirates. Biophysical characteristics should be reflected by lung compliance and, as a consequence, by improved blood oxygenation. Various animal models have been developed to evaluate the efficacy of surfactant replacement therapy on preterm and term animals. In vivo models can be divided in those, primarily involving surfactant deficiency, such as premature animal model, and those with secondary surfactant dysfunction or inactivation, such as meconium or acid aspiration models. This review is restricted to the in vivo and in vitro techniques handled by the authors in their research performed within the last years at both domestic and external laboratories.

Meconium aspiration syndrome (MAS) is a major cause of respiratory distress in both the term and postterm neonates. Obstruction of the airways, dysfunction of pulmonary surfactant, inflammation, lung edema, pulmonary vasoconstriction and bronchoconstriction participate in the pathogenesis of this disorder. Since the inflammatory changes associated with meconium aspiration cause a severe impairment of the lung parenchyma including surfactant and influence the reactivity of both vascular and airway smooth muscle, administration of anti-inflammatory drugs may be of benefit also in the management of MAS. This article reviews effects of various anti-inflammatory drugs used in experimental models of MAS as well as in the treatment of newborns with meconium aspiration. Meconium aspiration syndrome (MAS) MAS is a serious disease in both the term and post-term newborns. Obstruction of the airways by aspirated meconium with subsequent alveolar atelectasis behind the plug and air-trapping, inactivation of pulmonary surfactant, inflammation, edema, pulmonary vasoconstriction are often leading to persistent pulmonary hypertension (PPHN), and bronchoconstriction participate in the pathogenesis of MAS (Figure 1). Because meconium-induced inflammation with its multiple impacts on the lungs plays more important role than was previously thought, various anti-inflammatory drugs have been tested in the treatment of MAS. This article reviews inflammatory changes in MAS as a rationale for anti-inflammatory treatment and introduces anti-inflammatory drugs mostly used in the treatment of MAS.

Glucocorticoids may improve lung function in newborns with meconium aspiration syndrome (MAS), but information on the acute side effects of glucocorticoids in infants is limited. In this study using a rabbit model of MAS, we addressed the hypothesis that systemic administration of dexamethasone causes acute cardiovascular changes. Adult rabbits were treated with 2 intravenous doses of dexamethasone (0.5 mg/kg each) or saline at 0.5 h and 2.5 h after intratracheal instillation of human meconium or saline. Animals were oxygen-ventilated for 5 h after the first dose of treatment. Blood pressure, heart rate, and short-term heart rate variability (HRV) were analyzed during treatment, for 5 min immediately after each dose, and for the 5 h of the experiment. In the meconium-instilled animals, dexamethasone increased blood pressure, decreased heart rate, increased HRV parameters, and caused cardiac arrhythmia during and immediately after administration. In the saline-instilled animals, the effect of dexamethasone was inconsistent. In these animals, the acute effects of dexamethasone on blood pressure and cardiac rhythm were reversed after 30 min, whereas heart rate continued to decrease and HRV parameters continued to increase for 5 h after the first dose of dexamethasone. These effects were more pronounced in meconium-instilled animals. If systemic glucocorticoids are used in the treatment of MAS, cardiovascular side effects of glucocorticoids should be considered.

Phosphodiesterases (PDEs) are enzymes involved in the degradation of cAMP and cGMP. Selective PDE4 inhibitors (e.g., roflumilast) are effective in therapy of chronic obstructive pulmonary disease associated with neutrophil inflammation. The aim of this study was to evaluate the effects of a selective PDE4 inhibitor, YM976, on citric acid-induced cough, in vivo and in vitro airway smooth muscle reactivity to histamine, and on inflammatory mediators in ovalbumin-sensitized guinea pigs, with experimentally induced eosinophil inflammation. The YM976 was administered intraperitoneally at a dose of 1.0 mg/kg once daily for 7 days. Sensitization with ovalbumin led to a significant increase in the number of coughs, and in vivo and in vitro airway reactivity. Also, increased plasma levels of IL-4, IL-5, and PAF were observed, with a significant increase in the differential count of eosinophils in both blood and bronchoalveolar lavage fluid. The YM976 suppressed the number of coughs, the airway reactivity in tracheal tissue strips, and the IL-4 level. The findings indicate that PDE4 inhibition by YM976 exerts antitussive and anti-inflammatory effects in guinea pigs with ovalbumin-induced eosinophilic inflammation.

Neonatal meconium aspiration syndrome (MAS) can be treated by exogenous surfactant (S). However, aspirated meconium initiates local inflammation and oxidation which may inactivate surfactant and reduce its action. This experimental study estimated whether combined use of surfactant and the antioxidant N-acetylcysteine (NAC) can enhance effectiveness of therapy. Meconium-instilled rabbits were non-treated (M), treated with monotherapies (M + S, M + NAC), combined therapy (M + S + NAC), or received saline instead of meconium (controls, C). Surfactant therapy consisted of two lung lavages (BAL) with diluted Curosurf (5 mg phospholipids/ml, 10 ml/kg) followed by undiluted Curosurf (100 mg phospholipids/kg). N-acetylcysteine (Acc Injekt, 10 mg/kg) was given intravenously in M + S + NAC group 10 min after surfactant therapy. Animals were oxygen-ventilated for additional 5 h. Then, differential white cell count in the blood (WBC) was determined. Left lung was saline-lavaged and differential cell count in BAL was determined. In right lung tissue, wet/dry weight ratio, oxidation markers (TBARS, 3NT) and interleukines (IL-2, IL-6, IL-13, and TNFα) using ELISA and RT-PCR were estimated. Combined S + NAC therapy significantly decreased W/D ratio, TBARS, 3NT, and IL, whereas the effect of monotherapies (either S or NAC) was less obvious. In conclusion, addition of NAC to surfactant treatment may enhance the therapeutic outcome in MAS.

Phosphodiesterases (PDEs) represent a super-family of 11 enzymes hydrolyzing cyclic nucleotides into inactive 5′ monophosphates. Inhibition of PDEs leads to a variety of cellular effects, including airway smooth muscle relaxation, inhibition of cellular inflammation, and immune responses. In this study we focused on theophylline, a known non-selective inhibitor of PDEs. Theophylline has been used for decades in the treatment of chronic inflammatory airway diseases. It has a narrow therapeutic window and belongs to the drugs whose plasma concentration should be monitored. Therefore, the main goal of this study was to evaluate the plasma theophylline concentration and to determine its relevance to pharmacological effects after single and longer term (7 days) administration of theophylline at different doses (5, 10, 20, and 50 mg/kg) in guinea pigs. Airway hyperresponsiveness was assessed by repeated exposure to ovalbumin. Theophylline reduced specific airway resistance in response to histamine nebulization, measured in a double chamber body plethysmograph. A decrease in tracheal smooth muscle contractility after cumulative doses of histamine and acetylcholine was confirmed in vitro. A greater efficacy of theophylline after seven days long treatment indicates the predominance of its anti-inflammatory activity, which may be involved in the bronchodilating action.

Acute lung injury is characterized by lung edema, surfactant dysfunction, and inflammation. The main goal of our study was to evaluate effects of S-nitroso-N-acetyl-penicillamine (SNAP) on migration of cells into the lung and their activation, inducible NO synthase (iNOS) activity, and apoptosis in experimental acute lung injury (ALI) in rabbits. ALI was induced by repetitive lung lavage with saline. The animals were divided into the following groups: (1) ALI without therapy, (2) lung injury treated with SNAP (ALI + SNAP), and (3) healthy animals (Control). After 5 h of ventilation, total and differential counts of cells in the bronchoalveolar lavage fluid (BALF) were assessed. Concentrations of interleukins (IL)-1s, IL-6, and IL-8, endogenous secretory receptor for advanced glycation endproducts (esRAGE), sphingosine-1-phosphate receptor (S1PR)3, caspase-3, and mRNA expression of inducible NO synthase (iNOS) in lung tissue and nitrite/nitrate in plasma were analyzed. In the right lung, apoptotic cells were evaluated by TUNEL assay. In the animals with ALI, higher counts of cells, mainly neutrophils, in BALF and increased production of pro-inflammatory substances were observed compared with controls. SNAP therapy reduced a leak of cells into the lung and decreased concentrations of pro-inflammatory and apoptotic markers, reduced mRNA expression of iNOS, and decreased apoptotic index in the lung.

Patients with acute lung injury are ventilated by conventional mechanical ventilation (CMV) rather than high-frequency jet ventilation (HFJV). This study estimated the potential usefulness of HFJV in acute lung injury. The issue was addressed by comparing the effects on lung function of CMV and HFJV in two rabbit models of neonatal acute lung injury: repetitive saline lung lavage (LAV) and meconium aspiration syndrome (MAS) induced by intratracheal meconium instillation. The animals were then ventilated with either HFJV or CMV for 4 h. Ventilatory pressures, blood gases, and indexes of gas exchange were assessed. Lung edema formation was expressed as wet-dry lung weight ratio. Both LAV and MAS significantly decreased lung compliance, increased airway resistance, and caused severe hypoxemia, hypercarbia, and acidosis. Although CMV was superior to HFJV at 1 h of ventilation, there were no clinically relevant differences in lung function or edema formation between CMV and LAV in both models of respiratory insufficiency at 4 h of ventilation. We conclude that, HFJV may be used for ventilation in acute non-homogenous lung injury.

Surfactant lung lavage is a promising approach in the treatment of meconium aspiration syndrome (MAS). We hypothesise that the enrichment of modified natural surfactant with dextran will enhance meconium clearance from the airspaces during lung lavage and improve lung function in experimental MAS. Human meconium (30 mg/ml; 4 ml/kg) was instilled into the tracheal cannula of anaesthetised and paralysed adult rabbits to induce respiratory failure. The animals were then lavaged with saline (Sal), surfactant without (Surf) and with dextran (Surf+dex). Lung lavage (10 ml/kg in three portions) was performed with diluted surfactant (Curosurf, 10 mg/ml, 100 mg/kg) without or with dextran (3 mg/mg of surfactant phospholipids) or saline and the animals were conventionally ventilated with 100% O(2) for an additional hour. Lung functions were measured prior to and after meconium instillation, and 10, 30 and 60 min after lavage. The recovery of meconium in bronchoalveolar lavage (BAL) fluid was quantified. More meconium solids was recovered in the surfactant-lavaged than in the saline-lavaged groups (Surf: 12.4 +/- 3.9% and Surf+dex: 17.5 +/- 3.5% vs. Sal: 4.8 +/- 1.0%; both P0.01). Moreover, more meconium solids was obtained by Curosurf/dextran than by Curosurf-only lavage (P0.05). In the Surf group, the values for PaO(2)/FiO(2) were significantly higher than in the controls (at 60 min: 24.5 +/- 4.2 kPa vs.9.1 +/- 2.2 kPa, P0.01). An additional increase in oxygenation was seen in the Surf+dex group (at 60 min: 34.2 +/- 8.1 kPa, P vs. Surf group0.01). The lung-thorax compliance was higher in the Surf+dex group in comparison with the Sal and Surf groups (at 60 min: 9.6 +/- 0.9 vs.7.6 +/- 1.2, P0.01 and 8.0 +/- 0.7 ml/kPa/kg, P0.05). The enrichment of Curosurf with dextran improves meconium clearance and lung functions in surfactant-lavaged rabbits with meconium aspiration.

Evidence showed, that free radical species and nitric oxide (NO) or its derrivates are the key dominators in carcinogenesis. The aim of our study was to determine the alteration of NO derivates- nitrites, nitrates and 3-nitrotyrosine, as markers of oxidative/nitrosative stress in blood samples of lung cancer (LC) patients and to asses the importance of exhaled nitric oxide measurement (FeNO) in LC patients and and their relationship to type of cancer and smoking status. 54 newly diagnosed patients with LC and 43 healthy controls (HC) were studied. FeNO levels were measured by analyzer NIOX. Concentrations of NO 2- /NO 3– were assesed using the modified cadmium-reduction method based. 3-nitrotyrosine was assesed using specific antibody. Our results have shown that plasma nitrites concentrations in patiens with LC were significantly higher (4,41+/-2,24 µM) when compared with HC (2,53+/-1,39 µM). There was not difference between male and female, smokers and nonsmokers and LC types. There was not stastisticaly significant difference in level of nitrates in patients with LC (6,71+/-6,04 µM) and in HC (8,53+/-2,36 µM) regardless of gender, smoking status and type of cancer. Levels of 3-nitrotyrosin in patients with LC (0,22+/-0,17ng/ml) were significantly higher than in HC (-2,85 +/-0,34 ng/ml) regardless of type of cancer and smoking status. Patients with LC had significantly higher levels of FeNO (13ppb, IQR 8) than HC (10,1ppb, IQR 3,05) not depending on cancer type and smoking status. The prognosis of lung cancer is still poor because of the absence of valid approaches to its early detection. Exhaled breath analysis and measurements of NO derivates may provide useful assays in this field.

For treatment of severe neonatal meconium aspiration syndrome (MAS), lung-protective mechanical ventilation is essential. This study compared short-term effects of small-volume conventional mechanical ventilation and high-frequency oscillatory ventilation on lung function in experimentally-induced MAS. In conventionally-ventilated rabbits, MAS was induced by intratracheal instillation of meconium suspension (4 ml/kg, 25 mg/ml). Then, animals were ventilated conventionally with small-volume (f-50/min; VT-6 ml/kg) or with high frequency ventilation (f-10/s) for 4 h, with the evaluation of blood gases, ventilatory pressures, and pulmonary shunts. After sacrifice, left lung was saline-lavaged and cells in bronchoalveolar lavage fluid (BALF) were determined. Right lung was used for the estimation of lung edema formation (wet/dry weight ratio). Thiobarbituric acid-reactive substances (TBARS), oxidative damage markers, were detected in lung tissue and plasma. Meconium instillation worsened gas exchange, and induced inflammation and lung edema. Within 4 h of ventilation, high frequency ventilation improved arterial pH and CO2 elimination compared with conventional ventilation. However, no other significant differences in oxygenation, ventilatory pressures, shunts, BALF cell counts, TBARS concentrations, or edema formation were observed between the two kinds of ventilation. We conclude that high frequency ventilation has only a slight advantage over small-volume conventional ventilation in the model of meconium aspiration syndrome in that it improves CO2 elimination.

Autism spectrum disorder (ASD) is a severe neurodevelopmental disorder in early childhood characterized by impairment in communication and behavior. Recent research is focused on the immune dysregulation as a potential pathomechanism leading to ASD. Thus, we addressed the hypothesis that inflammatory activity might be enhanced in children suffering from ASD. We examined 15 children with ASD (13 boys/2 girls, mean age of 9.3 ± 0.7 years) and 20 age/gender-matched healthy subjects as a control group. All children were medication free and in good health. Hematological parameters in venous blood and plasma levels of pro-inflammatory cytokines - tumor necrosis factor alpha (TNF-α), interleukin 1s (IL-1s), and interleukin 8 (IL-8) – were assessed in each subject using human ultra-sensitive ELISA kits. In addition, TBARS as a marker of oxidative stress was evaluated. We found that the level of IL-8 was significantly increased in the ASD children, whereas the other markers remained unappreciably changed compared to controls (p = 0.003). In conclusion, the study demonstrates a discrete immune dysfunction in ASD of pro-inflammatory character.

We aimed to study the complexity and time asymmetry of short-term heart rate variability (HRV) as an index of complex neurocardiac control in response to stress using symbolic dynamics and time irreversibility methods. ECG was recorded at rest and during and after two stressors (Stroop, arithmetic test) in 70 healthy students. Symbolic dynamics parameters (NUPI, NCI, 0V%, 1V%, 2LV%, 2UV%), and time irreversibility indices (P%, G%, E) were evaluated. Additionally, HRV magnitude was quantified by linear parameters: spectral powers in low (LF) and high frequency (HF) bands. Our results showed a reduction of HRV complexity in stress (lower NUPI with both stressors, lower NCI with Stroop). Pattern classification analysis revealed significantly higher 0V% and lower 2LV% with both stressors, indicating a shift in sympathovagal balance, and significantly higher 1V% and lower 2UV% with Stroop. An unexpected result was found in time irreversibility: significantly lower G% and E with both stressors, P% index significantly declined only with arithmetic test. Linear HRV analysis confirmed vagal withdrawal (lower HF) with both stressors; LF significantly increased with Stroop and decreased with arithmetic test. Correlation analysis revealed no significant associations between symbolic dynamics and time irreversibility. Concluding, symbolic dynamics and time irreversibility could provide independent information related to alterations of neurocardiac control integrity in stress-related disease.

Background: The number of medical undergraduates taking part in Student Scientific Activities (SSA) at Jessenius Faculty of Medicine Comenius University in Slovakia remains low. The aim of this study was to discover some of the factors responsible and suggest improvements. Methods: An anonymous 30-item questionnaire was devised and sent to 245 medical undergraduates (UG) of the 1st, 2nd, 3rd and 5th years. Results: Foreign fellowships, postgraduate research, assistant posts at universities and financial incentives were cited as the main positive motivators for participation in UG student scientific research. Characteristics in tutors that encouraged student research were scientific knowledge, giving time to students and enthusiasm for research while poor infrastructure, tutor lack of time/interest, own time constraints, weak career motivation and lack of information were the strongest discouraging factors. Conclusion: Involvement of students in SSA is infl uenced by many factors. To increase the number of students taking part in SSA, student research and/or continuing to Ph.D and scientific career, these factors need to be addressed by medical schools.

Anti-inflammatory drugs are increasingly used for treatment of neonatal meconium aspiration syndrome (MAS), but their adverse effects are poorly known. Therefore, the aim of this study was to evaluate the effects of the antioxidant N-acetylcysteine on cardiovascular parameters in an animal model of MAS. Oxygen-ventilated rabbits were intratracheally instilled 4 mL/kg of meconium suspension (25 mg/mL) or saline. Thirty minutes later, meconium-instilled animals were given N-acetylcysteine (10 mg/kg, i.v.) or the same volume of saline. Changes in cardiovascular parameters (blood pressure, heart rate, and heart rate variability) were recorded over a 5-min course of solution administration, over 5 min after its end, and then hourly for 5 h. Oxidation markers (thiobarbituric acid-reactive substances (TBARS) and total antioxidant status) and aldosterone, as a non-specific marker of cardiovascular injury, were determined in plasma. Meconium instillation did not evoke any significant cardiovascular changes, but induced oxidative stress and elevated plasma aldosterone. N-acetylcysteine significantly reduced the mentioned markers of injury. However, its administration was associated with short-term increases in blood pressure and in several parameters of heart rate variability. Considering these effects of N-acetylcysteine, its intravenous administration in newborns with MAS should be carefully monitored.

Nitric oxide (NO) effects in airways are influenced by the activity of NO-synthase isoforms and NO metabolism. Inducible NO-synthase (iNOS), which produces large amounts of NO, is active during the inflammatory process. NO quickly reacts, producing reactive oxygen species (ROS). In this study we attempted to detect the expression of iNOS and markers of ROS in the airway hyperreactivity (AHR) condition. The study was performed in guinea pigs, divided into four groups. Two groups were treated with the non-selective inhibitor of NO-synthase L-NAME. The other two groups were used as controls. Exhaled NO was monitored in vivo, AHR was assessed both in vivo and in vitro, and the expression of iNOS in lung homogenate, and oxidative stress markers were measured in the venous blood. L-NAME significantly affected the AHR only in in vitro condition, blocked the expression of iNOS in control but not in sensitized animals, and decreased the level of exhaled NO. The results concerning the oxidative stress markers are equivocal. The study confirmed that NO is involved in the regulation of AHR; the effects being mediated via iNOS and ROS activity.

Chronic inflammatory diseases, associated with airway obstruction and cough, are usually treated with bronchodilating and anti-inflammatory drugs. Inhibition of phosphodiesterases (PDE) leads to both of these effects and influences apoptosis of immune cells. In chronic obstructive pulmonary disease, roflumilast, a selective PDE4 inhibitor, has been recently approved for pharmacotherapy. The aim of this study was to evaluate the effect of long-term administration of roflumilast in experimental allergic inflammation in guinea pigs. Male adult guinea pigs were used in the study. There were four experimental groups sensitized with ovalbumin for 14 days and thereafter treated per os, by inhalation, and intraperitoneally for 7 days with roflumilast or vehicle. A control group was left without sensitization. Roflumilast reduced specific airway resistance after nebulization of histamine, as measured in a double-chamber whole-body plethysmograph. This effect was confirmed in in vitro organ bath, with significant decreases in tracheal and lung smooth muscle contractility after cumulative doses of histamine. Suppression of hematological and immunological markers of inflammation and enhanced apoptosis in animals treated with roflumilast points to the possibility of a beneficial effect of roflumilast in allergic inflammation.

Meconium aspiration in newborns causes lung inflammation and injury, which may lead to meconium aspiration syndrome (MAS). In this study, the effect of the antioxidant N-acetylcysteine on respiratory and inflammatory parameters were studied in a model of MAS. Oxygen-ventilated rabbits were intratracheally given 4 mL/kg of meconium (25 mg/mL) or saline. Thirty minutes later, meconium-instilled animals were administered N-acetylcysteine (10 mg/kg; i.v.), or were left without treatment. The animals were oxygen-ventilated for additional 5 h. Ventilatory pressures, oxygenation, right-to-left pulmonary shunts, and leukocyte count were measured. At the end of experiment, trachea and lung were excised. The left lung was saline-lavaged and a total and differential count of cells in bronchoalveolar lavage fluid (BAL) was determined. Right lung tissue strips were used for detection of lung edema (expressed as wet/dry weight ratio) and peroxidation (expressed by thiobarbituric acid-reactive substances, TBARS). In lung and tracheal strips, airway reactivity to acetylcholine was measured. In addition, TBARS and total antioxidant status were determined in the plasma. Meconium instillation induced polymorphonuclear-derived inflammation and oxidative stress. N-acetylcysteine improved oxygenation, reduced lung edema, decreased polymorphonuclears in BAL fluid, and diminished peroxidation and meconium-induced airway hyperreactivity compared with untreated animals. In conclusion, N-acetylcysteine effectively improved lung functions in an animal model of MAS.

We studied a potential impact of chronic psychosocial load on the allostatic biomarkers – cardiac vagal activity, inflammation, and oxidative stress in healthy undergraduate students. Continuous resting ECG signals were monitored in a group of 16 female healthy students (age: 23.2 ± 0.2 years, BMI: 20.9 ± 0.5 kg/m2) at two time periods: right after holiday (rest period) and a day before final exams (stress period). Vagal activity was quantified by spectral analysis of heart rate variability at high frequency band (HF-HRV). The immune response was assessed from the level of tumor necrosis factor-alpha (TNF-α) in plasma. In addition, mean RR intervals were evaluated. We found that HF-HRV was significantly reduced and the TNF-α was increased in the stress period compared with the rest period. No significant changes were found in the RR interval. In conclusion, allostatic load induced by stress and the accompanying greater immune response decreased cardiovagal regulation in healthy young subjects. These findings may help understand the pathway by which stress can influence health and disease.

Meconium aspiration syndrome (MAS) is a major cause of respiratory insufficiency in the term and post-term newborns. There are several pathomechanisms participating in this disorder, particularly the airway obstruction, surfactant dysfunction, inflammation, lung edema, pulmonary vasoconstriction and bronchoconstriction. Inflammatory changes resulting from meconium aspiration cause severe impairment of lung parenchyma and surfactant, and influence the reactivity of both vascular and airway smooth muscle. Therefore, anti-inflammatory drugs may be of benefit in the management of MAS. This article reviews the pharmacological actions and side effects of various anti-inflammatory drugs used up to now in the experimental models of MAS and in the treatment of newborns with meconium aspiration.

Surfactant dysfunction in meconium aspiration syndrome (MAS) is caused by meconium components, by plasma proteins leaking through the injured alveolocapillary membrane and by substances originated in meconium-induced inflammation. Surfactant inactivation in MAS may be diminished by several ways. Firstly, aspirated meconium should be removed from the lungs to decrease concentrations of meconium inhibitors coming into the contact with surfactant in the alveolar compartment. Once the endogenous surfactant becomes inactivated, components of surfactant should be substituted by exogenous surfactant at a sufficient dose, and surfactant administration should be repeated, if oxygenation remains compromised. To delay the inactivation by inhibitors, exogenous surfactants may be enriched with surfactant proteins, phospholipids, or other substances such as polymers. Finally, to diminish an adverse action of products of meconium-induced inflammation on both endogenous and exogenously delivered surfactant, anti-inflammatory drugs may be administered. A combined therapeutic approach may result in better outcome in patients with MAS and in lower costs of treatment.

The best-studied store-operated Ca2+ channels (SOCs), Ca2+ release activated Ca2+ (CRAC) channels, are activated by depleting endoplasmic reticulum Ca2+ pool and mediate Ca2+ influx vitally important for Ca2+ restoration and many cellular function. CRAC channels were identified on immune and airway smooth muscle (ASM) cells. Emerging evidence points to its involvement in allergic airways diseases. This article evaluated therapeutic potency of CRAC antagonist in experimental animal model of allergic asthma. Allergic asthma, induced by repetitive exposure of guinea pigs to ovalbumine, was followed by 14 days therapy by CRAC antagonist (3-fluoropyridine-4-carboxylic acid, FPCA). In vivo changes of specific airways resistance (sRaw) evaluated bronchodilatory effect of FPCA and salbutamol. The method of citric acid-induced cough reflex assessed antitussive activity of FPCA and codeine. The measurement of exhaled NO (ENO), expression of inducible NO-synthase (iNOS) by RT-PCR and immunohistochemical staining of airways tissue verified anti-inflammatory effect of FPCA. Long-term administration of FPCA resulted in significant cough suppression and bronchodilation, both comparable to the effect of control drugs. FPCA significantly decreased ENO and iNOS expression, which together with immunohistochemical analysis validated its anti-inflammatory effect. Presented data confirmed CRAC channels as a promising target for treatment of respiratory diseases associated with allergic inflammation.

Phosphodiesterases (PDEs) are enzymes responsible for degradation of cAMP and cGMP in cells. Thus, PDE inhibitors may have significant clinical benefit in respiratory diseases associated with inflammation. The aim of the present study was to evaluate the effects of selective PDE4 (rolipram, ROL) and PDE7 inhibitors (BRL50481, BRL) on citric acid-induced cough, in vivo and in vitro airway smooth muscle reactivity in both healthy and ovalbumin sensitized guinea pigs. The drugs tested were administered intraperitoneally to male guinea pigs once daily for 7 days - ROL 1 mg/kg, BRL 1 mg/kg, and ROL+BRL 0.5 mg/kg. Double chamber whole body plethysmography was used for the evaluation of citric acid (0.6 M)-induced cough and specific airway resistance. An organ bath method was used for the measurement of tracheal and lung tissue strip contractions evoked by cumulative doses (10(-8)-10(-3) mol/L) of acetylcholine (ACH) and histamine (HIS). In healthy guinea pigs, the only significant relaxation was observed after ROL in ACH-induced contractions in vitro and the effect on cough was negligible. In ovalbumin-sensitized animals, more pronounced in vitro relaxing effects of BRL in HIS-induced contractions and of combination (ROL+BRL) in ACH-induced contractions were observed, with similar results in vivo, and no significant change in the number of cough efforts was observed in any of the groups tested. The results suggest that PDE4 and PDE7 inhibitors have stronger anti-inflammatory effects compared with direct effects on smooth muscle and cough, with a potential benefit of their concomitant administration.

Normobaric oxygen (NBO) therapy is commonly applied for the treatment of various diseases, including myocardial infarctions, but its effectiveness is controversial. Potential adverse effects of hyperoxia are related to excessive formation of free radicals. In the present study we examined the effect of 60-h NBO treatment on lipid peroxidation (LPO), activity of manganese superoxide dismutase (Mn-SOD) and mitochondrial enzymes of energy metabolism in guinea pig heart. NBO treatment resulted in significant accumulation of thiobarbituric acid reactive substances and loss of Mn-SOD activity despite slight elevation of Mn-SOD protein content. Activity of electron transport chain complex III decreased significantly, while activity of complex IV was slightly elevated and citrate synthase was unchanged. LPO, inhibition of Mn-SOD and complex III activities were more pronounced when inhaled oxygen was partially enriched with superoxide radical. In contrast, when O(2) was enriched with oxygen cation (O(2)●+), LPO and loss of Mn-SOD activity were prevented. Complex III activity in the O(2)●+-treated group remained depressed but activities of complex IV and citrate synthase were elevated. These data suggest that NBO treatment is associated with myocardial oxidative damage and attenuation of antioxidant defense, but these adverse effects can be partially attenuated by inhalation of O(2) enriched with oxygen cation.

Inflammation, oxidation, lung edema, and other factors participate in surfactant dysfunction in meconium aspiration syndrome (MAS). Therefore, we hypothesized that anti-inflammatory treatment may reverse surfactant dysfunction in the MAS model. Oxygen-ventilated rabbits were given meconium intratracheally (25 mg/ml, 4 ml/kg; Mec) or saline (Sal). Thirty minutes later, meconium-instilled animals were treated by glucocorticoids budesonide (0.25 mg/kg, i.t.) and dexamethasone (0.5 mg/kg, i.v.), or phosphodiesterase inhibitors aminophylline (2 mg/kg, i.v.) and olprinone (0.2 mg/kg, i.v.), or the antioxidant N-acetylcysteine (10 mg/kg, i.v.). Healthy, non-ventilated animals served as controls (Con). At the end of experiments, left lung was lavaged and a differential leukocyte count in sediment was estimated. The supernatant of lavage fluid was adjusted to a concentration of 0.5 mg phospholipids/ml. Surfactant quality was evaluated by capillary surfactometer and expressed by initial pressure and the time of capillary patency. The right lung was used to determine lung edema by wet/dry (W/D) weight ratio. Total antioxidant status (TAS) in blood plasma was evaluated. W/D ratio increased and capillary patency time shortened significantly, whereas the initial pressure increased and TAS decreased insignificantly in Sal vs. Con groups. Meconium instillation potentiated edema formation and neutrophil influx into the lungs, reduced capillary patency and TAS, and decreased the surfactant quality compared with both Sal and Con groups (p > 0.05). Each of the anti-inflammatory agents reduced lung edema and neutrophil influx into the lung and partly reversed surfactant dysfunction in the MAS model, with a superior effect observed after glucocorticoids and the antioxidant N-acetylcysteine.

Phosphodiesterases (PDEs) are enzymes responsible for degradation of cAMP and cGMP in cells. Thus, PDE inhibitors may have significant clinical benefit in respiratory diseases associated with inflammation. The aim of the present study was to evaluate the effects of selective PDE4 (rolipram, ROL) and PDE7 inhibitors (BRL50481, BRL) on citric acid-induced cough, in vivo and in vitro airway smooth muscle reactivity in both healthy and ovalbumin sensitized guinea pigs. The drugs tested were administered intraperitoneally to male guinea pigs once daily for 7 days – ROL 1 mg/kg, BRL 1 mg/kg, and ROL+BRL 0.5 mg/kg. Double chamber whole body plethysmography was used for the evaluation of citric acid (0.6 M)-induced cough and specific airway resistance. An organ bath method was used for the measurement of tracheal and lung tissue strip contractions evoked by cumulative doses (10−8–10−3 mol/L) of acetylcholine (ACH) and histamine (HIS). In healthy guinea pigs, the only significant relaxation was observed after ROL in ACH-induced contractions in vitro and the effect on cough was negligible. In ovalbumin-sensitized animals, more pronounced in vitro relaxing effects of BRL in HIS-induced contractions and of combination (ROL+BRL) in ACH-induced contractions were observed, with similar results in vivo, and no significant change in the number of cough efforts was observed in any of the groups tested. The results suggest that PDE4 and PDE7 inhibitors have stronger anti-inflammatory effects compared with direct effects on smooth muscle and cough, with a potential benefit of their concomitant administration.

As inflammation plays an important role in the pathogenesis of neonatal meconium aspiration syndrome (MAS), anti-inflammatory agents including inhibitors of phosphodiesterases (PDE) are increasingly used in the treatment. To evaluate side effects of PDE inhibitors, this study analyzed changes in blood pressure, heart rate (HR) and heart rate variability (HRV) during and after intravenous aminophylline in the animal model of MAS. Oxygen-ventilated rabbits were given meconium intratracheally (25 mg/ml, 4 ml/kg) or saline. Thirty minutes later, the animals were treated by intravenous aminophylline (Syntophyllin, 2 mg/kg) or saline (sham-treated controls). A second dose of the treatment was given 2 h later. During (5 min) and immediately after (5 min) the treatment, and during 5 h after the treatment, mean blood pressure in the femoral artery (MAP), HR and HRV were evaluated. In meconium-instilled animals, increases in MABP, HR, and HRV were observed already 5 min after aminophylline administration, while in saline-instilled animals aminophylline increased HR and caused inconsistant changes in HRV parameters compared to sham-treated animals. Within 5 h after the treatment administration, MAP, HR, and HRV parameters gradually returned to the initial values. Concluding, intravenous aminophylline may lead to acute cardiovascular changes. Thus, if aminophylline is used for treatment of MAS, its possible cardiovascular effects should be considered, particularly in patients with cardiovascular instability.

Since inflammation and oxidation play a key role in the pathophysiology of neonatal meconium aspiration syndrome, various anti-inflammatory drugs have been tested in the treatment. This study evaluated whether the phosphodiesterase (PDE) 3 inhibitor olprinone can alleviate meconium-induced inflammation and oxidative lung injury. Oxygen-ventilated rabbits intratracheally received 4 ml/kg of meconium (25 mg/ml) or saline. Thirty minutes after meconium/saline instillation, meconium-instilled animals were treated by intravenous olprinone (0.2 mg/kg) or were left without treatment. All animals were oxygen-ventilated for an additional 5 h. A bronchoalveolar lavage (BAL) of the left lungs was performed and differential leukocyte count in the sediment was estimated. The right lungs were used to determine lung edema by wet/dry weight ratio, as well as to detect oxidative damage to the lungs. In the lung tissue homogenate, total antioxidant status (TAS) was determined. In isolated lung mitochondria, the thiol group content, conjugated dienes, thiobarbituric acid-reactive substances (TBARS), dityrosine, lysine-lipid peroxidation products, and activity of cytochrome c oxidase (COX) were estimated. To evaluate the effects of meconium instillation and olprinone treatment on the systemic level, TBARS and TAS were determined in the blood plasma, as well. Meconium instillation increased the relative numbers of neutrophils and eosinophils in the BAL fluid, increased edema formation and concentrations of oxidation markers, and decreased TAS. Treatment with olprinone reduced the numbers of polymorphonuclears in the BAL fluid, decreased the formation of most oxidation markers in the lungs, reduced lung edema and prevented a decrease in TAS in the lung homogenate compared to non-treated animals. In the blood plasma, olprinone decreased TBARS and increased TAS compared to the non-treated group. Conclusion, the selective PDE3 inhibitor olprinone has shown potent antioxidative and anti-inflammatory effects in the meconium-induced oxidative lung injury.

Beside neonatal respiratory distress syndrome, secondary surfactant deficiency may occur in patients with mature lungs. Recent studies revealed quantitative and qualitative changes of lung surfactant in pulmonary thromboembolism (PTE) concerning the total phospholipids content in BAL fluid, alterations in surfactant phospholipids classes and a large-to-small aggregates ratio. Reduced expression of surfactant protein A (SP-A) mRNA and SP-A in lung tissue after pulmonary embolism was found. Serum levels of SP-A were significantly higher in patients with PTE than in other lung diseases, except COPD. Surfactant changes in PTE may result from damage of type II cells by hypoxia, leakage of plasma proteins into the airspaces and/or by reactive oxygen species. They can contribute to lung atelectasis and edema, and a further reduction in oxygen saturation as seen in clinical picture of PTE. Surfactant changes are reliable marker of lung injury that might become a prognostic indicator in patients with pulmonary thromboembolism.

ADHD is one of the most common mental disorders among children. We hypothesized that ADHD is associated with the impairment of the cardiac autonomic regulation. The aim of this study was to evaluate the cardiac autonomic regulation in children with ADHD at the rest and during orthostasis using short-term heart rate variability (HRV) analysis.Eighteen children with ADHD admitted to the Department of Children and Adolescent Psychiatry, Clinic of Psychiatry, University Hospital in Martin, Slovak Republic between January and September 2006 and 18 matched healthy subjects were recruited. HRV analysis was carried out in three positions: supine (S1)-orthostasis (O)-supine (S2). Evaluated parameters were: the mean R-R interval, mean squared successive difference (MSSD), spectral powers in low (LF) and high frequency (HF) bands, total power (TP), coefficients of component variance (CCV LF, CCV HF), LF/HF ratio.The mean R-R interval was significantly shorter in ADHD group compared to controls in all positions (P0.05, P0.001). S1: The parameters MSSD, CCV HF, logHFpower were significantly lower (P0.05, P0.05, P0.01) and ratio LF/HF was significantly higher (P0.05) in ADHD group compared to controls. O: The parameters MSSD, CCVHF, logHFpower, logTP were significantly lower in ADHD group compared to controls (P0.01, P0.05, P0.01, P0.01). S2: The parameters MSSD and logHFpower were significantly lower in children with ADHD compared to controls (P0.05).The children with ADHD had decreased cardiac vagal modulation and tachycardia in supine positions with altered ability of dynamic activation of the autonomic nervous system in response to orthostasis indicating changes in the cardiac autonomic regulation. Further studies need to be done on a larger sample to confirm these findings and to understand the underlying mechanisms.

Because cardiovascular functions and their control mechanisms may be influenced by meconium aspiration and by treatment, cardiovascular parameters including heart rate variability (HRV) were evaluated after meconium instillation and treatment with dexamethasone.Adult rabbits were anesthetized, paralyzed, and artificially ventilated. Meconium suspension (25 mg/mL, 4 mL/kg) was instilled intratracheally to induce respiratory failure. Thirty minutes later, animals received i.v. dexamethasone (0.5 mg/kg; dexa group, n = 6) or were left without treatment (control group, n = 5). All animals were ventilated for an additional 5 h. Mean heart rate (MHR), mean blood pressure (MBP), central venous pressure (CVP), and time and spectral analyses of HRV were registered and evaluated. Blood gases were measured and right-to-left pulmonary shunts (RLS) calculated.Immediately after meconium instillation, MBP, CVP, and RLS increased and MHR decreased (P0.05). MHR and MBP were restored within several minutes, while CVP and RLS remained high until the end of experiment. Thirty minutes after meconium instillation, slightly but non-significantly higher spectral powers in all frequency bands of HRV were found (P0.05). Dexamethasone treatment enhanced oxygenation (P0.05) and slightly reduced PaCO(2) (P0.05), increased parasympathetic activity expressed by mean squared successive difference and decreased spectral power in the very low frequency band (P0.05) compared to controls, but had no significant effect on MHR, MBP, CVP, and RLS.Single-dose i.v. dexamethasone showed a trend to improve gas exchange, however, increased parasympathetic activity, what should be considered in use of corticosteroids in the treatment of meconium aspiration syndrome.

Meconium aspiration syndrome is a serious neonatal disease with complex pathophysiology. With respect to the contribution of meconium-induced lung edema, inflammation and vasoconstriction on the course of the disease, glucocorticoids are increasingly used in the treatment of MAS despite the fact that principal questions on the choice of GCs derivative, mode of delivery and dosing have not been answered yet. To bring a complex insight into the topic, this article reviews the pathomechanisms of MAS, mechanisms of action of GCs, as well as the advantages and disadvantages of GCs administration in experimental models and newborns with MAS.

Meconium aspiration syndrome (MAS) triggers inflammatory and oxidative pathways which can inactivate both pulmonary surfactant and therapeutically given exogenous surfactant. Glucocorticoid budesonide added to exogenous surfactant can inhibit inflammation and thereby enhance treatment efficacy. Neonatal meconium (25 mg/ml, 4 ml/kg) was administered intratracheally (i.t.) to rabbits. When the MAS model was prepared, animals were treated with budesonide i.t. (Pulmicort, 0.25 mg/kg, M+B); with surfactant lung lavage (Curosurf®, 10 ml/kg, 5 mg phospholipids/ml, M+S) followed by undiluted Curosurf® i.t. (100 mg phospholipids/kg); with combination of budesonide and surfactant (M+S+B); or were untreated (M); or served as controls with saline i.t. instead of meconium (C). Animals were oxygen-ventilated for additional 5 h. Cell counts in the blood and bronchoalveolar lavage fluid (BAL), lung edema formation (wet/dry weight ratio), oxidative damage of lipids/ proteins and inflammatory expression profiles (IL-2, IL-6, IL-13, TNF-α) in the lung homogenate and plasma were determined. Combined surfactant+budesonide therapy was the most effective in reduction of neutrophil counts in BAL, oxidative damage, levels and mRNA expression of cytokines in the lung, and lung edema formation compared to untreated animals. Curosurf fortified with budesonide mitigated lung inflammation and oxidative modifications what indicate the perspectives of this treatment combination for MAS therapy.

The study was designed to prove the hypothesis that lipopolysaccharide (LPS)-induced fever elicits the changes in surfactant specific proteins, potentially related to thermal tachypnea. In adult rats fever was induced by intraperitoneal administration of LPS at a dose 100 µg/kg of body weight; control group received saline. Respiratory parameters, arterial blood gases and pH and colonic body temperature (BT) were recorded. Five hours later, surfactant proteins (SP) A, B, C and D were evaluated in bronchoalveolar lavage fluid (BALF) and lung tissue (LT). LPS evoked monophasic thermic response (at 300 min 38.7±0.2 vs. 36.4±0.3 °C, P0.05) and an increase in minute ventilation due to changes in breathing rate and tidal volume. LPS-instilled animals had higher levels of SP-A and SP-D in LT (P0.05 and 0.01), and higher SP-D in BALF (P0.01) than controls. SP-B increased in LT and SP-C in BALF of animals with LPS (both P0.05 vs. controls). The changes in all surfactant specific proteins are present in LPS-induced fever. Alterations of proteins related to local immune mechanisms (SP-A, SP-D) are probably a part of general inflammatory response to pyrogen. Changes in proteins related to surface activity (SP-B and SP-C) might reflect the effort of the body to stabilize the lungs in thermal challenge.

Acute lung injury (ALI) is associated with deterioration of alveolar-capillary lining and transmigration and activation of inflammatory cells. Whereas a selective phosphodiesterase-4 (PDE4) inhibitor roflumilast has exerted potent anti-inflammatory properties, this study evaluated if its intravenous delivery can influence inflammation, edema formation, and respiratory parameters in rabbits with a lavage-induced model of ALI. ALI was induced by repetitive saline lung lavage (30 ml/kg). Animals were divided into 3 groups: ALI without therapy (ALI), ALI treated with roflumilast i.v. (1 mg/kg; ALI+Rofl), and healthy ventilated controls (Control), and were ventilated for following 4 h. Respiratory parameters (blood gases, ventilatory pressures, lung compliance, oxygenation indexes etc.) were measured and calculated regularly. At the end of experiment, animals were overdosed by anesthetics. Total and differential counts of cells in bronchoalveolar lavage fluid (BAL) were estimated microscopically. Lung edema was expressed as wet/dry lung weight ratio. Treatment with roflumilast reduced leak of cells (P

Meconium aspiration syndrome (MAS) in newborns is characterized mainly by respiratory failure due to surfactant dysfunction and inflammation. Previous meta-analyses did not prove any effect of exogenous surfactant treatment nor glucocorticoid administration on final outcome of children with MAS despite oxygenation improvement. As we supposed there is the need to intervene in both these fields simultaneously, we evaluated therapeutic effect of combination of exogenous surfactant and selective inhibitor of NF-κB (IKK-NBD peptide). Young New Zealand rabbits were instilled by meconium suspension and treated by surfactant alone or surfactant in combination with IKK-NBD, and oxygen-ventilated for 5 h. PaO2/FiO2, oxygenation index, oxygen saturation and ventilation efficiency index were evaluated every hour; post mortem, total and differential leukocyte counts were investigated in bronchoalveolar lavage fluid (BALF) and inflammatory, oxidative and apoptotic markers were assessed in lung tissue homogenates. Exogenous surfactant combined with IKK-NBD improved oxygenation, reduced neutrophil count in BALF and levels of IL-1β, IL-6, p38 MAPK and caspase 3 in comparison with surfactant-only therapy. It seems that inhibition of inflammation may be strong supporting factor in surfactant treatment of MAS.

The aim of the study was to evaluate short-term heart rate variability (HRV) as an index of cardiac autonomic control in rats with lipopolysaccharide (LPS)-induced endotoxemia. Animals were injected intraperitoneally with LPS (100 µg/kg b.w.) and control group with an equivalent volume of saline. ECG recordings were done before (base) and 60, 120, 180, 240 and 300 min after LPS or saline administration. HRV magnitude was quantified by time and frequency-domain analysis (mean RR interval, SDRR, RMSSD, spectral powers in low (LF) and high frequency (HF) bands. Heart tissue homogenates and plasma were analyzed to determine interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α) and oxidative stress level (TBARS). Administration of lipopolysaccharide was followed by continuous rise in colonic body temperature compared to saline-treated controls. Endotoxemia in rats was accompanied by significant decrease in HRV spectral activity in high-frequency range at maximal body temperature (logHFpower: 1.2±0.5 vs. 1.9±0.6 ms2, P

Inflammation and other immune responses are involved in the variety of diseases and disorders. The acute response to endotoxemia includes activation of innate immune mechanisms as well as changes in autonomic nervous activity. The autonomic nervous system and the inflammatory response are intimately linked and sympathetic and vagal nerves are thought to have anti-inflammation functions. The basic functional circuit between vagus nerve and inflammatory response was identified and the neuroimmunomodulation loop was called cholinergic anti-inflammatory pathway. Unique function of vagus nerve in the anti-inflammatory reflex arc was found in many experimental and pre-clinical studies. They brought evidence on the cholinergic signaling interacting with systemic and local inflammation, particularly suppressing immune cells function. Pharmacolo-gical/electrical modulation of vagal activity suppressed TNF-α and other proinflammatory cytokines production and had beneficial therapeutic effects. Many questions related to mapping, linking and targeting of vagal-immune interactions have been elucidated and brought understanding of its basic physiology and provided the initial support for development of Tracey´s inflammatory reflex. This review summarizes and critically assesses the current knowledge defining cholinergic anti-inflammatory pathway with main focus on studies employing an experimental approach and emphasizes the potential of modulation of vagally-mediated anti-inflammatory pathway in the treatment strategies.

Severe meconium aspiration syndrome (MAS) in newborns is often treated by exogenous surfactant. Because its efficacy is reduced by meconium-induced inflammation, glucocorticoid budesonide was added into surfactant preparation Curosurf to enhance efficacy of the surfactant therapy in experimental model of MAS. Oxygen-ventilated rabbits were intratracheally given meconium (25 mg/ml, 4 ml/kg) to induce respiratory failure. Thirty minutes later, animals were treated by intratracheal budesonide (0.25 mg/kg) or surfactant lung lavage (10 ml/kg, 5 mg phospholipids/ml) repeated twice, followed by undiluted Curosurf (100 mg phospholipids/kg) or by the above mentioned surfactant treatment with the last surfactant dose fortified with budesonide (0.25 mg/kg) or were untreated. Animals were ventilated for additional 5 hours and respiratory parameters were measured regularly. After sacrificing animals, wet-dry lung weight ratio was evaluated and plasma levels of interleukins (IL)-1beta, -6, -8, and TNF-alpha were measured by ELISA method. Efficacy of the given therapies to enhance lung functions and to diminish lung edema formation and inflammation increased from budesonide-only and surfactant-only therapy to surfactant+budesonide therapy. Combined therapy improved gas exchange from 30 min of administration, and showed a longer-lasting effect than surfactant-only therapy. In conclusions, budesonide additionally improved the effects of exogenous surfactant in experimental MAS.