Experimental Pneumonia Research Articles

The Annexin A1/FPR2 pathway controls the inflammatory response and bacterial dissemination in experimental pneumococcal pneumonia.

Streptococcus pneumoniae is a major cause of community-acquired pneumonia leading to high mortality rates. Inflammation triggered by pneumococcal infection is necessary for bacterial clearance but must be spatially and temporally regulated to prevent further tissue damage and bacterial dissemination. Annexin A1 (AnxA1) mainly acts through Formyl Peptide Receptor 2 (FPR2) inducing the resolution of inflammation. Here, we have evaluated the role of AnxA1 and FPR2 during pneumococcal pneumonia in mice. For that, AnxA1, Fpr2/3 knockout (KO) mice and wild-type (WT) controls were infected intranasally with S pneumoniae. AnxA1 and Fpr2/3 KO mice were highly susceptible to infection, displaying uncontrolled inflammation, increased bacterial dissemination, and pulmonary dysfunction compared to WT animals. Mechanistically, the absence of AnxA1 resulted in the loss of lung barrier integrity and increased neutrophil activation upon S pneumoniae stimulation. Importantly, treatment of WT or AnxA1 KO-infected mice with Ac2-26 decreased inflammation, lung damage, and bacterial burden in the airways by increasing macrophage phagocytosis. Conversely, Ac2-26 peptide was ineffective to afford protection in Fpr2/3 KO mice during infection. Altogether, these findings show that AnxA1, via FPR2, controls inflammation and bacterial dissemination during pneumococcal pneumonia by promoting host defenses, suggesting AnxA1-based peptides as a novel therapeutic strategy to control pneumococcal pneumonia.

The level of endogenic intoxication in the dynamics of development of experimental contact dermatitis and experimental pneumonia and their correction by thiotriazoline

Тhe aim of our work was to find out the peculiarities of changes ofendogenous intoxication indices in guinea pig blood during theformation of combined pathology - experimental contact dermatitis and experimental pneumonia and correction of their disorders with thiotriazoline.The paper found a gradual increase in the molecules of mediummass and erythrocyte index of intoxication in guinea pig serum with experimental contact dermatitis and experimental pneumonia with the highest degree of expression on the 18thday of the experiment, and this may be may indicate the development of endogenous intoxication of the animal body. At the same time, the use of the drug thiotriazoline caused the decrease of the studied indicators, which gives grounds to stateits positive effect on certain markers of endogenous intoxicationand the feasibility of further research.

The level of endogenic intoxication in the dynamics of development of experimental contact dermatitis and experimental pneumonia and their correction by thiotriazoline

The level of endogenic intoxication in the dynamics of development of experimental contact dermatitis and experimental pneumonia and their correction by thiotriazoline

Characteristic of individual indicators of phagocytic activity of leukocytes under conditions of formation of experimental contact dermatitis and experimental pneumonia and the effect of the drug thiotriazoline

Characteristic of individual indicators of phagocytic activity of leukocytes under conditions of formation of experimental contact dermatitis and experimental pneumonia and the effect of the drug thiotriazoline

Effects of curcumin on pulmonary inflammation and p38 expression in an infant murine model of pneumococcal pneumonia

Objective To investigate the effects of curcumin on pneumococcal pneumonia-induced pneumonia, apoptosis and p38 MAPK expression in infant mice. Methods A total of 60 male infant C57BL/6 mice at three weeks of age were randomly divided into 6 groups: control group, model group, high-dose curcumin treatment group, middle-dose curcumin treatment group, low-dose curcumin treatment group and SB203580 treatment group. The Curcumin and SB203580 were intraperitoneally applied at doses of 200, 60, and 20 mg/kg (for curcumin) and 100 mg/kg (for SB203580) from two days before bacterial infection to three days post-infection. The control group and model group were intraperitoneally injected with an equal volume of saline. The model group, curcumin treatment groups and SB203580 treatment group were transnasally inoculated with approximately 106 CFU/ml of pneumococcal pneumonia in 50 μl of PBS applied to the tip of the nose to establish the experimental pneumococcal pneumonia. Subsequently, all the mice were killed and lung tissues were harvested for hematoxylin-eosin staining, calculation of lung score indexes, measurement of IL-1β and TNF-α contents by ELISA, and measurement of Bax, Bcl-2and p38 MAPK expression by Western blot. Results Compared to the model group, the edema score (0.50 ± 0.10, 1.51 ± 0.16, 1.38±0.11, vs. 2.50 ± 0.20), hemorrhage score (0.32 ± 0.09, 1.01 ± 0.11, 0.85±0.09 vs. 1.80 ± 0.20), inflammatory cell infiltrate score (0.35 ± 0.09, 1.61 ± 0.16, 1.52±0.10 vs. 3.21 ± 0.22), small airway damage score (0.12 ± 0.03, 0.53 ± 0.14, 0.50±0.04 vs. 1.12 ± 0.19) in the medium-, high-dose group and SB203580 treatment group significantly decreased (P<0.01). Compared to the model group, the contents of IL-1β (20.38 ± 1.69 pg/ml, 25.73 ± 2.08 pg/ml vs. 40.22 ± 5.70 pg/ml) and TNF-α (160.39 ± 15.81 pg/ml, 198.67 ± 18.97 pg/ml vs. 282.22 ± 25.30 pg/ml), Bax/Bcl-2 (0.31 ± 0.05, 0.53 ± 0.06 vs. 1.79 ± 0.17) and expression of phosphorylated p38 MAPK (0.69 ± 0.05, 0.81 ± 0.07 vs. 1.71 ± 0.14) in the high-dose group and SB203580 treeatment group significantly decreased (P<0.01). Conclusions Curcumin can inhibit the inflammatory response and cellular apoptosis in the lungs of mice with pneumococcal pneumonia, and the mechanisms maybe related to its inhibition of p38 MAPK expression. Key words: Curcumin; Pneumonia; Pneumococcal infections; Apoptosis; Inflammation; p38 Mitogen-activated protein kinases; Mice

Pathogenetic substantiation of thiotriazoline use on the basis of disorders of proteolysis processes and protease inhibitors under conditions of contact dermatitis and experimental pneumonia

Pathogenetic substantiation of thiotriazoline use on the basis of disorders of proteolysis processes and protease inhibitors under conditions of contact dermatitis and experimental pneumonia

Development of an aerosolized Mannheimia haemolytica experimental pneumonia model in clean-catch colostrum-deprived calves

Mannheimia haemolytica is an important cause of bovine respiratory disease (BRD). BRD is usually a multifactorial disease with host factors and viral infections influencing pathogenesis. Previous studies that have attempted to experimentally induce pneumonia using aerosolized M. haemolytica alone have produced inconsistent results, yet an aerosol model would be useful to study the details of early infection and to investigate the role of innate defences in pathogenesis. The objective of these studies was to develop and characterize an aerosolized M. haemolytica disease model. In an initial study, conventionally raised calves with higher levels of antibody against M. haemolytica leukotoxin developed acute respiratory distress and diffuse alveolar damage, but did not develop bronchopneumonia, following challenge with M. haemolytica serotype 1. Clean-catch colostrum-deprived calves challenged with 1 × 1010 colony forming units of M. haemolytica serotype 1 consistently developed bronchopneumonia, with elevations in rectal temperature, serum haptoglobin, plasma fibrinogen, and blood neutrophils. Mannheimia haemolytica serotype 1 was consistently isolated from the nasal cavities and lungs of challenged calves. Despite distribution of aerosol and isolation of M. haemolytica in all lung lobes, gross lesions were mainly observed in the cranioventral area of lung. Gross and histologic lesions included neutrophilic bronchopneumonia and fibrinous pleuritis, with oat cells (necrotic neutrophils with streaming nuclei), and areas of coagulative necrosis, which are similar to lesions in naturally occurring BRD. Thus, challenge with M. haemolytica serotype 1 and use of clean-catch colostrum-deprived calves with low or absent antibody titres allowed development of an effective aerosol challenge model that induced typical clinical disease and lesions.

Protection Efficacy of the rLTB-R1 Chimera against Experimental Swine Mycoplasmal Pneumonia

Background: Mycoplasma hyopneumoniaeis the etiological agent of the Swine Mycoplasmal Pneumonia (SMP), one of the most economically significant diseases in the swine industry worldwide. Commonly used vaccines for SMP control consist of inactivated whole cells (bacterins). These vaccines are efficacious against M. hyopneumoniaechallenge, but do not prevent colonization by the pathogen or completely eliminate pneumonia. P97 adhesin is conserved in the M. pneumoniae virulent strains, therefore it is an attractive target to be used in recombinant vaccines against M. hyopneumoniae. The aim of the present study was to evaluate protection afforded by rLTB-R1, a recombinant chimera composed by LTB fused with the R1 repeat region of P97 adhesin of M. hyopneumoniae, in specific-pathogen-free (SPF) piglets vaccinated by intranasal or intramuscular route and challenged with a pathogenic strain of M. hyopneumoniae.Materials, Methods &amp; Results:PCR products of the LTB and R1 coding sequences were fused, then cloned into pETDEST42™ expression vector. The rLTB-R1 was expressed in Escherichia coli BL21 (DE3) Salt induction (SI).They were allocated into three groups: four piglets were intranasally vaccinated with 1 mg of rLTB-R1 solubilized in 1 mL of PBS at 0 and 14 days (IN rLTB-R1 group); four piglets were intramuscularly vaccinated with 1 mg of rLTB-R1 solubilized in 1 mL of PBS at 0 and 14 days (IM rLTB-R1 group);three piglets were intranasally and intramuscularly inoculated with 1 mL of PBS (control group).Two weeks after the last immunization (28 day), piglets were intratracheally challenged with 10 mL of a suspension containing 109color-changing unit (CCU) of pathogenic M. hyopneumoniae 7448 strain on three consecutive days. Until the challenge (28 days), intranasal and intramuscular vaccination with rLTB-R1 induced seroconversions of anti-R1 systemic antibodies of 1.6 and 4.6 ×, respectively. The IN rLTB-R1 group had no pulmonary lesion, rLTB-R1 conferred protection against experimental SMP. On the other hand, IM rLTB-R1 and control groups had on average 7.24% and 8.46% of pulmonary lesion, respectively, showing that intramuscular vaccination with rLTB-R1 did not confer protection.Discussion:The rLTB-R1, when intranasally administrated to mice, elicited production of anti-R1 IgA in trachea and bronchi as well as specific Th1 response, suggesting an adequate stimulation of the mucosal immune system. We believe that rLTB-R1 induced a similar immune response in piglets intranasally vaccinated, conferring protection against experimental SMP. The present study, the rLTB-R1 alone, without any chemical adjuvant, stimulated a significant seroconversion of anti-R1 systemic antibodies in pigs intramuscularly vaccinated, showing the potential of LTB as a parenteral adjuvant in swine vaccination.Previous work has shown that the intramuscular administration route was evaluated in pigs because mice intramuscularly vaccinated with rLTB-R1 presented significant levels of anti-R1 IgA in trachea and bronchi, suggesting that rLTB can stimulate some degree of mucosal immunity even if not delivered by a mucosal route.However, in the present study, piglets intramuscularly vaccinated with rLTB-R1 presented high levels of anti-R1 systemic antibodies, they were not protected.On the other hand, intranasal vaccination of piglets with rLTB-R1 elicited low levels of anti-R1 systemic antibodies (1.6 × at 28 days), but it conferred full protection against experimental SMP. The present study demonstrated that intranasal vaccination of piglets with rLTB-R1 conferred protection against experimental SMP. A more detailed analysis of the protective immune response induced by rLTB-R1 in pigs is currently being performed.

Overlapping Roles for Interleukin-36 Cytokines in Protective Host Defense against Murine Legionella pneumophila Pneumonia.

Legionella pneumophila causes life-threatening pneumonia culminating in acute lung injury. Innate and adaptive cytokines play an important role in host defense against L. pneumophila infection. Interleukin-36 (IL-36) cytokines are recently described members of the larger IL-1 cytokine family known to exert potent inflammatory effects. In this study, we elucidated the role for IL-36 cytokines in experimental pneumonia caused by L. pneumophila Intratracheal (i.t.) administration of L. pneumophila induced the upregulation of both IL-36α and IL-36γ mRNA and protein production in the lung. Compared to the findings for L. pneumophila-infected wild-type (WT) mice, the i.t. administration of L. pneumophila to IL-36 receptor-deficient (IL-36R-/-) mice resulted in increased mortality, a delay in lung bacterial clearance, increased L. pneumophila dissemination to extrapulmonary organs, and impaired glucose homeostasis. Impaired lung bacterial clearance in IL-36R-/- mice was associated with a significantly reduced accumulation of inflammatory cells and the decreased production of proinflammatory cytokines and chemokines. Ex vivo, reduced expression of costimulatory molecules and impaired M1 polarization were observed in alveolar macrophages isolated from infected IL-36R-/- mice compared to macrophages from WT mice. While L. pneumophila-induced mortality in IL-36α- or IL-36γ-deficient mice was not different from that in WT animals, antibody-mediated neutralization of IL-36γ in IL-36α-/- mice resulted in mortality similar to that observed in IL-36R-/- mice, indicating redundant and overlapping roles for these cytokines in experimental murine L. pneumophila pneumonia.

PLGA-encapsulation of the Pseudomonas aeruginosa PopB vaccine antigen improves Th17 responses and confers protection against experimental acute pneumonia

The Pseudomonas aeruginosa type III secretion system protein PopB and its chaperon protein PcrH, when co-administered with the adjuvant curdlan, elicit Th17 responses after intranasal immunization of mice. These PopB/PcrH-curdlan vaccines protect mice against acute lethal pneumonia in an IL-17-dependent fashion involving CD4 helper T cells secreting IL-17 (Th17 cells). In this study, we tested whether encapsulation of PopB/PcrH in poly-lactic-co-glycolic acid (PLGA) nanoparticles could elicit Th17 responses to PopB. Recombinant PopB/PcrH or PcrH alone was encapsulated into PLGA nanoparticles. Mice (FVB/N) were intranasally immunized with the PLGA-PopB/PcrH nanoparticles, PLGA-PcrH nanoparticles, PLGA alone, or PopB/PcrH alone. The protective efficacy was assessed in an acute lung infection model with a lethal dose of an ExoU-producing version of P. aeruginosa strain PAO1. Th17 responses were assayed by intracellular flow cytometry and by ELISA for IL-17 in supernatants of splenocytes co-cultured with purified PopB/PcrH. PLGA-PopB/PcrH-immunized mice showed 3–4-fold higher Th17 responses both in the lung and in the spleen compared to mice immunized with empty PLGA or PopB/PcrH alone. After challenge with P. aeruginosa, PLGA-PopB/PcrH-immunized mice showed significantly lower bacterial counts in the lungs and improved survival. In conclusion, encapsulation of PopB/PcrH in PLGA nanoparticles can elicit Th17 responses to intranasal vaccination and protect mice against acute lethal P. aeruginosa pneumonia.

Design, Synthesis, and Biological Evaluation of Novel 7-[(3 aS,7 aS)-3 a-Aminohexahydropyrano[3,4- c]pyrrol-2(3 H)-yl]-8-methoxyquinolines with Potent Antibacterial Activity against Respiratory Pathogens.

Novel 7-[(3 aS,7 aS)-3 a-aminohexahydropyrano[3,4- c]pyrrol-2(3 H)-yl]-6-fluoro-1-[(1 R,2 S)-2- fluorocyclopropyl]-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid 5 (DS21412020) was designed and synthesized to obtain potent antibacterial drugs for the treatment of respiratory tract infections. Compound 5 possessing a trans-fused pyranose ring on the pyrrolidine moiety at the C-7 position of the quinolone scaffold exhibited potent in vitro antibacterial activity against respiratory pathogens, including quinolone-resistant and methicillin-resistant Staphylococcus aureus (QR- MRSA) and quinolone-resistant Escherichia coli (QR- E. coli). Furthermore, compound 5 showed in vivo activity against the experimental murine pneumonia model due to penicillin-resistant Streptococcus pneumoniae ( PRSP) and favorable profiles in preliminary toxicological and nonclinical pharmacokinetic studies. In particular, the reduced lipophilicity and basicity of compound 5 as compared to those of the previously synthesized carba-type compound 4 resulted in a significant reduction in the human ether-a-go-go (hERG) related gene channel inhibition, which have the potential to prolong the QT interval.

A research pathway for the study of the delivery and disposition of nebulised antibiotics: an incremental approach from in vitro to large animal models

BackgroundNebulised antibiotics are frequently used for the prevention or treatment of ventilator-associated pneumonia. Many factors may influence pulmonary drug concentrations with inaccurate dosing schedules potentially leading to therapeutic failure and/or the emergence of antibiotic resistance. We describe a research pathway for studying the pharmacokinetics of a nebulised antibiotic during mechanical ventilation using in vitro methods and ovine models, using tobramycin as the study antibiotic.MethodsIn vitro studies using a laser diffractometer and a bacterial-viral filter were used to measure the effect of the type and size of tracheal tubes and antibiotic concentration on the particle size distribution of the tobramycin 400 mg (4 ml; 100 mg/ml) and 160 mg (4 ml, 40 mg/ml) aerosol and nebulised mass delivered. To compare the regional drug distribution in the lung of two routes (intravenous and nebulised) of drug administration of tobramycin 400 mg, technetium-99m-labelled tobramycin 400 mg with planar nuclear medicine imaging was used in a mechanically ventilated ovine model. To measure tobramycin concentrations by intravenous and nebulised tobramycin 400 mg (4 ml, 100 mg/ml) administration in the lung interstitial space (ISF) fluid and blood of mechanically ventilated sheep, the microdialysis technique was used over an 8-h duration.ResultsTobramycin 100 mg/ml achieved a higher lung dose (121.3 mg) compared to 40 mg/ml (41.3 mg) solution. The imaging study with labelled tobramycin indicated that nebulised tobramycin distributed more extensively into each lung zone of the mechanically ventilated sheep than intravenous administration. A higher lung ISF peak concentration of tobramycin was observed with nebulised tobramycin (40.8 mg/l) compared to intravenous route (19.0 mg/l).ConclusionsThe research methods appear promising to describe lung pharmacokinetics for formulations intended for nebulisation during mechanical ventilation. These methods need further validation in an experimental pneumonia model to be able to contribute toward optimising dosing regimens to inform clinical trials and/or clinical use.

ОСОБЕННОСТИ МОРФОЛОГИЧЕСКИХ И ЦИТОЛОГИЧЕСКИХ ИЗМЕНЕНИЙ ЛЁГКИХ И ДИАФРАГМЫ ПРИ ХРОНИЧЕСКОМ ГНОЙНОМ ВОСПАЛЕНИИ ЛЁГКИХ (ЭКСПЕРИМЕНТАЛЬНОЕ ИССЛЕДОВАНИЕ)

We induce a model of experimental chronic suppurative pneumonia (e-CSP) by prolonged mechanical irritation of the bronchi by the method of Batyreva Z. B., and Shamirzaev N. X in white rats. The purpose and objectives are to study the morphology and cellular response of lung tissue and the walls of the diaphragmatic muscles in e-CSP. During the examination on 30th and 45th days from the beginning of the experiment with the background of purulent inflammation of the lungs we determined mild manifestations of inflammatory changes on the sections of the tissue. There were cellular shifts in the bronchial mucosa, lung tissue and diaphragm with lymphoid reaction and morphological changes in the tissues. These anifestations were characterized by capillary and arterial fullness, focal lymphocytic-macrophage infiltration between the alveolar septa, moderate daily edema, dystrophic and compensatory changes in the lung tissue and walls of the diaphragm. Morphological changes in rats were haracterized by focal infiltration of lymphoid elements, moderate interstitial edema with impaired blood circulation in the pulmonary tissue and the muscular part of the diaphragm wall. On drug-prints in the bronchi and, especially in the lungs, there was a revival of both blood and tissue protective cells at the site of inflammation. The main feature of cytological changes in the long-standing form of chronic purulent process in the lungs is a lymphoid reaction with the appearance of young plasma cells, occurring against the background of reduced activity of macrophages, indicating a decrease in the protective capabilities of the body in e-CSP. The revealed morphological and cytological changes occurring in the pulmonary and diaphragm tissues testified to simultaneous inclusion of the pulmonary tissue and diaphragm in the inflammatory process, which must be taken into account in practical health care.

Stabilization of Hypoxia-Inducible Factor-1 Alpha Augments the Therapeutic Capacity of Bone Marrow-Derived Mesenchymal Stem Cells in Experimental Pneumonia.

Bone marrow-derived mesenchymal stem cells (MSCs) have therapeutic effects in experimental models of lung injury. Hypoxia-inducible factor-1 alpha (HIF-1α) is a transcriptional regulator that influences cellular metabolism, energetics, and survival under hypoxic conditions. The current study investigated the effects of stabilizing HIF-1α on the therapeutic capacity of MSCs in an experimental mouse model of bacterial pneumonia. HIF-1α stabilization was achieved by the small molecule prolyl-hydroxlase inhibitor, AKB-4924 (Aerpio Therapeutics, Inc.), which blocks the pathway for HIF-1α degradation in the proteosome. In vitro, pre-treatment with AKB-4924 increased HIF-1α levels in MSCs, reduced the kinetics of their cell death when exposed to cytotoxic stimuli, and increased their antibacterial capacity. In vivo, AKB-4924 enhanced MSC therapeutic capacity in experimental pneumonia as quantified by a sustainable survival benefit, greater bacterial clearance from the lung, decreased lung injury, and reduced inflammatory indices. These results suggest that HIF-1α stabilization in MSCs, achieved ex vivo, may represent a promising approach to augment the therapeutic benefit of these cells in severe pneumonia complicated by acute lung injury.

Effects of herbal multicomponent dietary supplement in experimental pneumonia

Effects of herbal multicomponent dietary supplement in experimental pneumonia

SCH79797 improves outcomes in experimental bacterial pneumonia by boosting neutrophil killing and direct antibiotic activity.

The role of protease-activated receptor 1 (PAR1) in the pathogenesis of pneumonia and sepsis is ambiguous given the existing literature. As PAR1 is classically activated by the coagulation-based protease thrombin and leads to vascular leakage, our hypothesis was that PAR1 blockade with SCH79797 would be therapeutically beneficial in an experimental model of murine Gram-negative pneumonia. In this study, we administered SCH79797 via the intrapulmonary route 6 h after the establishment of Escherichia coli pneumonia and observed a significant improvement in survival, lung injury, bacterial clearance and inflammation. We focused on neutrophils as a potential target of the PAR1 antagonist, since they are the predominant inflammatory cell type in the infected lung. Neutrophils appear to express PAR1 at low levels and the PAR1 antagonist SCH79797 enhanced neutrophil killing. Part of this effect may be explained by alterations in the generation of reactive oxygen species (ROS). SCH79797 also led to robust neutrophil extracellular trap (NET) generation and cathelicidin-related antimicrobial peptide (CRAMP) release by neutrophils. Surprisingly, SCH79797 also had a potent, direct antibiotic effect with disruption of the E. coli cell membrane. However, the newer-generation PAR1 antagonist, vorapaxar (SCH530348), had no appreciable effect on neutrophil activity or direct bacterial killing, which suggests the effects seen with SCH79797 may be PAR1 independent. In summary, we observed that intrapulmonary treatment with SCH79797 has significant therapeutic effects in a model of E. coli pneumonia that appear to be due, in part, to both neutrophil-stimulating and direct antibacterial effects of SCH79797.

Cefquinome-loaded microsphere formulations against Klebsiella pneumonia infection during experimental infections

The aim of this study was to prepare cefquinome-loaded polylactic acid microspheres and to evaluate their in vitro and in vivo characteristics and pharmacodynamics for the therapy of pneumonia in a rat model. Microspheres were prepared using a 0.7 mm two-fluid nozzle spray drier in one step resulting in spherical and smooth microspheres of uniform size (9.8 ± 3.6 μm). The encapsulation efficiency and drug loading of cefquinome were 91.6 ± 2.6% and 18.7 ± 1.2%, respectively. In vitro release of cefquinome from the microspheres was sustained for 36 h. Cefquinome-loaded polylactic acid microspheres as a drug delivery system was successful for clearing experimental Klebsiella pneumonia lung infections. A decrease in inflammatory cells and an inhibition of inflammatory cytokines TNF-α, IL-1β and IL-8 after microspheres treatment was found. Changes in cytokine levels and types are secondary manifestations of drug bactericidal effects. Rats were considered to be microbiologically cured because the bacterial load was less than 100 CFU/g. These results also indicated that the spray-drying method of loading therapeutic drug into polylactic acid microspheres is a straightforward and safe method for lung-targeting therapy in animals.

Vasculotide reduces pulmonary hyperpermeability in experimental pneumococcal pneumonia

BackgroundCommunity-acquired pneumonia (CAP) is a significant cause of morbidity and mortality worldwide. Despite effective antimicrobial therapy, CAP can induce pulmonary endothelial hyperpermeability resulting in life-threatening lung failure due to an exaggerated host-pathogen interaction. Treatment of acute lung injury is mainly supportive because key elements of inflammation-induced barrier disruption remain undetermined. Angiopoietin-1 (Ang-1)-mediated Tie2 activation reduces, and the Ang-1 antagonist Ang-2 increases, inflammation and endothelial permeability in sepsis. Vasculotide (VT) is a polyethylene glycol-clustered Tie2-binding peptide that mimics the actions of Ang-1. The aim of our study was to experimentally test whether VT is capable of diminishing pneumonia-induced lung injury.MethodsVT binding and phosphorylation of Tie2 were analyzed using tryptophan fluorescence spectroscopy and phospho-Tie-2 enzyme-linked immunosorbent assay. Human and murine lung endothelial cells were investigated by immunofluorescence staining and electric cell-substrate impedance sensing. Pulmonary hyperpermeability was quantified in VT-pretreated, isolated, perfused, and ventilated mouse lungs stimulated with the pneumococcal exotoxin pneumolysin (PLY). Furthermore, Streptococcus pneumoniae-infected mice were therapeutically treated with VT.ResultsVT showed dose-dependent binding and phosphorylation of Tie2. Pretreatment with VT protected lung endothelial cell monolayers from PLY-induced disruption. In isolated mouse lungs, VT decreased PLY-induced pulmonary permeability. Likewise, therapeutic treatment with VT of S. pneumoniae-infected mice significantly reduced pneumonia-induced hyperpermeability. However, effects by VT on the pulmonary or systemic inflammatory response were not observed.ConclusionsVT promoted pulmonary endothelial stability and reduced lung permeability in different models of pneumococcal pneumonia. Thus, VT may provide a novel therapeutic perspective for reduction of permeability in pneumococcal pneumonia-induced lung injury.

ВПЛИВ ПРЕПАРАТУ “ТІОТРИАЗОЛІН” НА СТАН ЕНДОГЕННОЇ ІНТОКСИКАЦІЇ У ПІЗНІЙ ПЕРІОД РОЗВИТКУ ВИРАЗКОВОЇ ХВОРОБИ ШЛУНКА В УМОВАХ ЕКСПЕРИМЕНТАЛЬНОЇ ПНЕВМОНІЇ

Пневмонія і виразкова хвороба шлунка – одні з найбільш поширених захворювань людини, які в ХХІ ст. залишаються важливими медико-соціальними проблемами.Мета дослідження – встановити ступінь ендогенної інтоксикації у пізній період розвитку виразкової хвороби шлунка (ВХШ) і експериментальної пневмонії (ЕП), а також вплив препарату “Tіотриазолін” на порушені показники.Матеріали і методи дослідження. Дослідження проводили на 49 морських свинках-самцях масою 180–210 г. Експериментальну пневмонію викликали за методом В. Н. Шляпникова, Т. Л. Солодова, виразкову хворобу шлунка моделювали за методом В. И. Комарова. Визначали вміст МСМ при довжині хвилі 254 нм за методом І. А. Волчегорского, Д. А. Дятлова, Е. І. Львовскої та ін., еритроцитарний індекс інтоксикації (ЕІІ) за методом А. А. Тогобаєва, А. В. Кургузкіна, І. В. Рікуна та ін. Тіотриазолін вводили внутрішньом’язово у дозі 100 мг на 1 кг маси щоденно з 10 до 18 доби експерименту і декапітували тварин під ефірним наркозом на 10 та 18 доби формування запального процесу в легенях і виразкової хвороби шлунка.Результати досліджень та їх обговорення. Еритроцитарний індекс інтоксикації в крові у тварин із ВХШ і ЕП на 10 добу значно підвищився – 85,2 % (p&lt;0,05) відносно контрольних тварин. Результати подальших досліджень ЕІІ на 18 добу цих моделей хвороб виявили його зростання, порівняно з інтактними тваринами, – підвищився на 96,3 % (p&lt;0,05). Рівень МСМ на 10 добу зріс відносно тварин першої групи на 98,5 % (p&lt;0,05), а надалі цей показник зазнав свого апогею – 107,2 % (p&lt;0,05).Висновки. Виявлено наростання ендогенної інтоксикації у пізній період розвитку ЕП і ВХШ. Використання препарату “Тіотриазолін” зумовлює позитивний його вплив на концентрацію ЕІІ і МСМ за умов розвитку ЕП і ВХШ.

Anti-inflammatory and antioxidant effect of cerium dioxide nanoparticles immobilized on the surface of silica nanoparticles in rat experimental pneumonia

A massage with the potent counter-inflammatory material, cerium dioxide nanoparticles, is promising and the antioxidant properties of CeO2 are considered the main, if not the only, mechanism of this action. Nevertheless, the elimination of ceria nano-particles from the organism is very slow and there is a strong concern for toxic effect of ceria due to its accumulation. To overcome this problem, we engineered a combined material in which cerium nanoparticles were immobilized on the surface of silica nanoparticles (CeO2 NP), which is shown to be easily removed from an organism and could be used as carriers for nano-ceria. In our study particle size was 220±5nm, Zeta-potential −4.5mV (in water), surface charge density −17.22μC/cm2 (at pH 7).Thirty-six male Wistar rats, 5 months old and 250–290g were divided into four groups: 1) control; 2) CeO2 NP treatment; 3) experimental pneumonia (i/p LPS injection, 1mg/kg); and 4) experimental pneumonia treated with CeO2 NP (4 times during the study in dosage of 0.6mg/kg with an orogastric catheter). Gas exchange and pulmonary ventilation were measured four times: 0, 1, 3 and 24h after LPS injection in both untreated and CeO2 NP-treated animals. The mRNA of TNF-α, Il-6, and CxCL2 were determined by RT-PCR. ROS-generation in blood plasma and lung tissue homogenates were measured by means of lucigenin- and luminol-enhanced chemiluminescence.Endotoxemia in the acute phase was associated with: (1) pathological changes in lung morphology; (2) increase of ROS generation; (3) enhanced expression of CxCL2; and (4) a gradual decrease of VO2 and VE. CeO2 NP treatment of intact animals did not make any changes in all studied parameters except for a significant augmentation of VO2 and VE. CeO2 NP treatment of rats with pneumonia created positive changes in diminishing lung tissue injury, decreasing ROS generation in blood and lung tissue and decreasing pro-inflammatory cytokine expression (TNF-α, Il-6 and CxCL2). Oxygen consumption in this group was increased compared to the LPS pneumonia group.In our study we have shown anti-inflammatory and antioxidant effects of CeO2 NP. In addition, this paper is the first to report that CeO2 NP stimulates oxygen consumption in both healthy rats, and rats with pneumonia. We propose the key in understanding the mechanisms behind the phenomena lies in the property of CeO2 NP to scavenge ROS and the influence of this potent antioxidant on mitochondrial function. The study of biodistribution and elimination of СеО2NP is the purpose of our ongoing study.