Methacholine dose response curve and acceptability criteria of respiratory mechanics modeling.

Aim: This study aimed to analyze the Constant Phase Model (CPM) Coefficient of Determination (COD) and an index of harmonic distortion ([Formula: see text]) behavior in intravenous methacholine dose response curve. We studied the COD and [Formula: see text] behavior of Control and Lung Inflammation (OVA) groups of mice and we proposed an alternative for moments when the CPM should not be applied. Methods: 9-week female BALB/c mice were studied, 8 of the control group (23.11 ± 1.27 g) and 11 of the lung inflammation group (OVA) (21.45 ± 2.16 g). The COD values were obtained during the respiratory mechanics assessment via Forced Oscillation Technique (FOT) and the [Formula: see text] was estimated a posteriori. Both control and OVA groups were submitted to 4 doses of Methacholine (MCh) protocol. Results: A strong correlation between COD and [Formula: see text] was present at the last two doses (0.3 mg/kg: r = -0.75, p = 0.0013 and 1 mg/kg: r = -0.91; p < 0.0001) in the OVA group. Differences were found in doses of 0.3 mg/kg between control and OVA for the maximum values of Rn (Newtonian Resistance) and G (tissue viscous); and between groups at PBS and doses of 0.03, 0.1 and 0.3 mg/kg for H (Elastance). A similar behavior was observed for the analysis of Area Under the Curve with the exclusion of the 3 first measurements of each dose. However, in this scenario, the comparison with the maximum value presented a higher discriminatory capacity of the parameters associated with the parenchyma. Conclusions: During severe bronchoconstriction there is a strong negative correlation between model goodness of fit and nonlinearities levels, reinforcing that COD is a robust acceptance criterion, whether still simple and easily obtained from the ventilator. We also pointed out the area under the CPM parameters dose response curve is a useful and can be used as a complementary analysis to peak comparison following bolus injections of methacholine.

Biseugenol Exhibited Anti-Inflammatory and Anti-Asthmatic Effects in an Asthma Mouse Model of Mixed-Granulocytic Asthma.

In the present work, the anti-inflammatory and antiasthmatic potential of biseugenol, isolated as the main component from n-hexane extract from leaves of Nectandra leucantha and chemically prepared using oxidative coupling from eugenol, was evaluated in an experimental model of mixed-granulocytic asthma. Initially, in silico studies of biseugenol showed good predictions for drug-likeness, with adherence to Lipinski's rules of five (RO5), good Absorption, Distribution, Metabolism and Excretion (ADME) properties and no alerts for Pan-Assay Interference Compounds (PAINS), indicating adequate adherence to perform in vivo assays. Biseugenol (20 mg·kg-1) was thus administered intraperitoneally (four days of treatment) and resulted in a significant reduction in both eosinophils and neutrophils of bronchoalveolar lavage fluid in ovalbumin-sensitized mice with no statistical difference from dexamethasone (5 mg·kg-1). As for lung function parameters, biseugenol (20 mg·kg-1) significantly reduced airway and tissue damping in comparison to ovalbumin group, with similar efficacy to positive control dexamethasone. Airway hyperresponsiveness to intravenous methacholine was reduced with biseugenol but was inferior to dexamethasone in higher doses. In conclusion, biseugenol displayed antiasthmatic effects, as observed through the reduction of inflammation and airway hyperresponsiveness, with similar effects to dexamethasone, on mixed-granulocytic ovalbumin-sensitized mice.

Blockage of the P2X7 Receptor Attenuates Harmful Changes Produced by Ischemia and Reperfusion in the Myenteric Plexus.

INTRODUCTION: Our work analyzed the effects of a P2X7 receptor antagonist, Brilliant Blue G (BBG), on rat ileum myenteric plexus following ischemia and reperfusion (ISR) induced by 45 min of ileal artery occlusion with an atraumatic vascular clamp with 24 h (ISR 24-h group) or 14 d of reperfusion (ISR 14-d group). MATERIAL AND METHODS: Either BBG (50 mg/kg or 100 mg/kg, BBG50 or BBG100 groups) or saline (vehicle) was administered subcutaneously 1 h after ischemia in the ISR 24-h group or once daily for the 5 d after ischemia in the ISR 14-d group (n = 5 per group). We evaluated the neuronal density and profile area by examining the number of neutrophils in the intestinal layers, protein expression levels of the P2X7 receptor, intestinal motility and immunoreactivity for the P2X7 receptor, nitric oxide synthase, neurofilament-200, and choline acetyl transferase in myenteric neurons. RESULTS: The neuronal density and profile area were restored by BBG following ISR. The ischemic groups showed alterations in P2X7 receptor protein expression and the number of neutrophils in the intestine and decreased intestinal motility, all of which were recovered by BBG treatment. CONCLUSION: We concluded that ISR morphologically and functionally affected the intestine and that its effects were reversed by BBG treatment, suggesting the P2X7 receptor as a therapeutic target.

Acute lung injury induced by intestinal ischemia and reperfusion is altered in obese female mice.

RATIONAL: Acute lung injury (ALI) is a common complication after intestinal ischemia and reperfusion (I/R) injury that can lead to acute respiratory distress syndrome (ARDS). We have previously demonstrated that females are protected against lung damage induced by intestinal I/R through an estrogen mediated mechanism. OBJECTIVES: To investigate the effect of obesity on ALI induced by intestinal I/R in female mice. METHODS: C57Bl/6 female mice were fed with a standard low-fat diet (SD) or a high-fat diet (HFD) for 9 weeks. Intestinal I/R injury was induced by a 45 min occlusion of the mesenteric artery followed by 2 and 24 h of reperfusion. RESULTS: Significant increase in lung myeloperoxidase expression (MPO) and neutrophil numbers of SD and HFD mice occurred at 2 h and 24 h of reperfusion. Furthermore, HFD mice presented a significant increase in lung eosinophil peroxidase (EPO) expression and eosinophil numbers compared to SD mice. Lung wet/dry weight ratio was significantly greater in HFD mice at 2 and 24 h of reperfusion, accompanied by a significant increase in the expression of inducible NO in the lung tissue and a significant decrease in arterial oxygen saturation at 24 h of reperfusion relative to SD mice. CONCLUSION: Obesity predisposes female mice to increased pulmonary oedema and deterioration in gas exchange, which is accompanied by an increase in iNOS expression in the lung.

Estradiol mediates the long-lasting lung inflammation induced by intestinal ischemia and reperfusion.

BACKGROUND: Lung inflammation is one of the main consequences of intestinal ischemia reperfusion (intestinal IR) and, in severe cases, can lead to acute respiratory distress syndrome and death. We have previously demonstrated that estradiol exerts a protective effect on lung edema and cytokine release caused by intestinal IR in male rats. MATERIALS AND METHODS: We investigated the role of estradiol on the generation of interleukin (IL)-1ß, IL-10, vascular endothelial growth factor (VEGF), and cytokine-induced neutrophil chemoattractant 1 (CINC-1) in a female rat model of intestinal IR. Blood and bone marrow leukocytes were also quantified. Seven-days-ovariectomized rats were subjected to intestinal IR by occlusion of the superior mesenteric artery for 45 min. After reperfusion of the tissue for 2 h, the rats were sacrificed. Lung tissue was collected, cultured for 24 h and assayed. RESULTS: We observed a significant increase in serum levels of IL-10, CINC-1, uric acid and circulating, but not bone marrow, leukocyte numbers. In addition, intestinal IR induced a significant increase in the ex-vivo lung levels of IL-1ß, IL-10, and VEGF. Treatment with 17ß-estradiol before the induction of intestinal IR prevented the systemic release of IL-10, CINC-1, and uric acid, but it did not affect the leukocytosis. In addition, 17ß-estradiol significantly prevented the ex-vivo release of IL-1ß and VEGF from lung tissue. CONCLUSIONS: We demonstrated that intestinal IR interferes with lung homeostasis, priming the tissue to generate proinflammatory mediators for at least 24 h postischemia. Furthermore, our data confirm that the inflammatory responses caused by intestinal IR are estradiol mediated.

High dose of formaldehyde exposure during pregnancy increases neutrophils lung influx evoked by ovalbumin in the offspring.

OBJECTIVE: Considering that asthma might have their onset in the intrauterine life and the exposure to FA during pregnancy interferes in the immune system of offspring, here we hypothesized that high dose of FA exposure during pregnancy could to contribute for development and severity of asthma in the offspring. METHODS: Pregnant Wistar rats were submitted to FA inhalation (6.13 mg/m(3), 1 h/day, 5 days/week, for 21 days) or vehicle (distillated water). After 30 days of birth, the offspring was sensitized with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge, the analyses were performed. Non-manipulated rats were used as basal parameters. RESULTS: Our data show that the exposure to high dose of FA during pregnancy predisposes the development of neutrophilic lung inflammation in the offspring, as observed by the profile of cells and cytokines in the lung. CONCLUSION: This study contributes to the understanding of effects of pollution on the development of lung diseases.

Sex-related differences in lung inflammation after brain death.

BACKGROUND: Donor sex has been suggested to be a factor influencing organ transplantation outcome. Sex hormones possess inflammatory and immune-mediating properties; therefore, immune responses may differ between males and females. Brain death (BD) affects organ function by numerous mechanisms including alterations in hemodynamics, hormonal changes, and increased systemic inflammation. In this study, we investigated sex-dependent differences in the evolution of lung inflammation in a rat model of BD. MATERIALS AND METHODS: BD was induced by a sudden increase in intracranial pressure by rapidly inflating a balloon catheter inserted into the intracranial space. Groups of male, female, and ovariectomized (OVx) female rats were used. Lung vascular permeability, inducible nitric oxide synthase, and intercellular adhesion molecule 1 expression were analyzed 6 h after BD. Serum female sex hormones, vascular endothelial growth factor, and cytokine-induced neutrophil chemoattractant 1 levels were also quantified. Lung sections were analyzed by histology. RESULTS: After 6 h of BD, serum estradiol and progesterone concentrations in female rats were significantly reduced. Lung microvascular permeability was increased in females compared to males. Cytokine-induced neutrophil chemoattractant 1 and vascular endothelial growth factor concentrations were increased in female rats compared to males. Furthermore, female rats showed higher levels of leukocyte infiltration and inducible nitric oxide synthase expression in the lung parenchyma. CONCLUSIONS: Our results indicate that the more severe lung inflammation in female animals after BD might be related to acute estradiol reduction. Based on our findings, we believe that, in a future study, a group of female treated with estradiol after BD could indicate a possible therapy for the control of lung inflammation in the female donor.

Exposure to low doses of formaldehyde during pregnancy suppresses the development of allergic lung inflammation in offspring.

Formaldehyde (FA) is an environmental and occupational pollutant, and its toxic effects on the immune system have been shown. Nevertheless, no data are available regarding the programming mechanisms after FA exposure and its repercussions for the immune systems of offspring. In this study, our objective was to investigate the effects of low-dose exposure of FA on pregnant rats and its repercussion for the development of allergic lung inflammation in offspring. Pregnant Wistar rats were assigned in 3 groups: P (rats exposed to FA (0.75 ppm, 1 h/day, 5 days/week, for 21 days)), C (rats exposed to vehicle of FA (distillated water)) and B (rats non-manipulated). After 30 days of age, the offspring was sensitised with ovalbumin (OVA)-alum and challenged with aerosolized OVA (1%, 15 min, 3 days). After 24 h the OVA challenge the parameters were evaluated. Our data showed that low-dose exposure to FA during pregnancy induced low birth weight and suppressed the development of allergic lung inflammation and tracheal hyperresponsiveness in offspring by mechanisms mediated by reduced anaphylactic antibodies synthesis, IL-6 and TNF-alpha secretion. Elevated levels of IL-10 were found. Any systemic alteration was detected in the exposed pregnant rats, although oxidative stress in the uterine environment was evident at the moment of the delivery based on elevated COX-1 expression and reduced cNOS and SOD-2 in the uterus. Therefore, we show the putative programming mechanisms induced by FA on the immune system for the first time and the mechanisms involved may be related to oxidative stress in the foetal microenvironment.

Effects of ischemia and reperfusion on subpopulations of rat enteric neurons expressing the P2X7 receptor.

BACKGROUND: Intestinal ischemia followed by reperfusion (I/R) may occur following intestinal obstruction. In rats, I/R in the small intestine leads to structural changes accompanied by neuronal death. AIM: To analyze the impact of I/R injury on different neuronal populations in the myenteric plexus of rat ileum. METHODS: The ileal artery was occluded for 35 min and animals were euthanized 6, 24, and 72 h, and 1 week later. Immunohistochemistry was performed with antibodies against the P2X7 receptor as well as nitric oxide synthase (NOS), calbindin, calretinin, choline acetyltransferase (ChAT), or the pan-neuronal marker anti-HuC/D. RESULTS: Double immunolabeling demonstrated that 100% of NOS-, calbindin-, calretinin-, and ChAT-immunoreactive neurons in all groups expressed the P2X7 receptor. Following I/R, neuronal density decreased by 22.6% in P2X7 receptor-immunoreactive neurons, and decreased by 46.7, 38, 39.8, 21.7, and 20% in NOS-, calbindin-, calretinin-, ChAT-, and HuC/D-immunoreactive neurons, respectively, at 6, 24, and 72 h and 1 week following injury compared to the control and sham groups. We also observed a 14% increase in the neuronal cell body profile area of the NOS-immunoreactive neurons at 6 and 24 h post-I/R and a 14% increase in ChAT-immunoreactive neurons at 1 week following I/R. However, the average size of the calretinin-immunoreactive neurons was reduced by 12% at 6 h post-I/R and increased by 8% at 24 h post-I/R. CONCLUSIONS: This work demonstrates that I/R is associated with a significant loss of different subpopulations of neurons in the myenteric plexus accompanied by morphological changes, all of which may underlie conditions related to intestinal motility disorder.

Intestinal lymph-borne factors induce lung release of inflammatory mediators and expression of adhesion molecules after an intestinal ischemic insult.

BACKGROUND: Intestinal ischemia and reperfusion (I/R) is a documented cause of acute lung injury (ALI) and systemic inflammation. We previously reported that obstruction of thoracic lymphatic flow during intestinal I/R blunts pulmonary neutrophil recruitment and microvascular injury and decreases the systemic levels of tumor necrosis factor. Here, we consider the existence of a gut-lung axis promoting the induction of systemic inflammation, whereby drained intestinal lymph stimulates lung expression of adhesion molecules and matrix components and generation of inflammatory mediators. MATERIAL AND METHODS: Upon administration of anesthesia, male Wistar rats were subjected to occlusion of the superior mesenteric artery for 45 min, followed by 2 h of intestinal reperfusion (I/R); groups of rats were subjected to I/R with or without thoracic lymphatic duct ligation immediately before the procedure. The non-manipulated rats were used to investigate basal parameters. RESULTS: Obstruction of thoracic lymphatic flow before intestinal I/R decreased the ability of cultured lung tissue explants to release IL-1ß, IL-10, and VEGF. In contrast, lymphatic obstruction normalized the elevated lung expression of PECAM-1 caused by intestinal I/R. On the other hand, lung E-selectin expression was significantly reduced, whereas fibronectin expression and collagen synthesis were not affected. Lymph levels of LTB(4) and TXB(2) were found to be significantly increased. CONCLUSIONS: These data suggest that lymph factors drained from the intestine during ischemic trauma stimulate the lung to generate inflammatory mediators and alter the expression of adhesion molecules. Disturbances in lung homeostasis mediated by lymph might contribute to the spread of inflammatory processes, thereby accounting for the systemic inflammation induced by intestinal I/R.

3,4-methylenedioxymethamphetamine (ecstasy) decreases inflammation and airway reactivity in a murine model of asthma.

OBJECTIVE: 3,4-Methylenedioxymethamphetamine (MDMA), or ecstasy, is a synthetic drug used recreationally, mainly by young people. It has been suggested that MDMA has a Th cell skewing effect, in which Th1 cell activity is suppressed and Th2 cell activity is increased. Experimental allergic airway inflammation in ovalbumin (OVA)-sensitized rodents is a useful model to study Th2 response; therefore, based on the Th2 skewing effect of MDMA, we studied MDMA in a model of allergic lung inflammation in OVA-sensitized mice. METHODS: We evaluated cell trafficking in the bronchoalveolar lavage fluid, blood and bone marrow; cytokine production; L-selectin expression and lung histology. We also investigated the effects of MDMA on tracheal reactivity in vitro and mast cell degranulation. RESULTS: We found that MDMA given prior to OVA challenge in OVA-sensitized mice decreased leukocyte migration into the lung, as revealed by a lower cell count in the bronchoalveolar lavage fluid and lung histologic analysis. We also showed that MDMA decreased expression of both Th2-like cytokines (IL-4, IL-5 and IL-10) and adhesion molecules (L-selectin). Moreover, we showed that the hypothalamus-pituitary-adrenal axis is partially involved in the MDMA-induced reduction in leukocyte migration into the lung. Finally, we showed that MDMA decreased tracheal reactivity to methacholine as well as mast cell degranulation in situ. CONCLUSIONS: Thus, we report here that MDMA given prior to OVA challenge in OVA-sensitized allergic mice is able to decrease lung inflammation and airway reactivity and that hypothalamus-pituitary-adrenal axis activation is partially involved. Together, the data strongly suggest an involvement of a neuroimmune mechanism in the effects of MDMA on lung inflammatory response and cell recruitment to the lungs of allergic animals.

Different Phenotypes in Asthma: Clinical Findings and Experimental Animal Models.

Asthma is a respiratory allergic disease presenting a high prevalence worldwide, and it is responsible for several complications throughout life, including death. Fortunately, asthma is no longer recognized as a unique manifestation but as a very heterogenic manifestation. Its phenotypes and endotypes are known, respectively, as pathologic and molecular features that might not be directly associated with each other. The increasing number of studies covering this issue has brought significant insights and knowledge that are constantly expanding. In this review, we intended to summarize this new information obtained from clinical studies, which not only allowed for the creation of patient clusters by means of personalized medicine and a deeper molecular evaluation, but also created a connection with data obtained from experimental models, especially murine models. We gathered information regarding sensitization and trigger and emphasizing the most relevant phenotypes and endotypes, such as Th2-high asthma and Th2-low asthma, which included smoking and obesity-related asthma and mixed and paucigranulocytic asthma, not only in physiopathology and the clinic but also in how these phenotypes can be determined with relative similarity using murine models. We also further investigated how clinical studies have been treating patients using newly developed drugs focusing on specific biomarkers that are more relevant according to the patient's clinical manifestation of the disease.

Simvastatin protects against intestinal ischemia/reperfusion-induced pulmonary artery dysfunction.

AIMS: The lung is an important target organ damage in intestinal ischemia/reperfusion (II/R), but mechanisms involved in II/R-induced pulmonary artery (PA) dysfunction, as well as its treatment, are not clear. The present study aimed to investigate the mechanisms involved in the II/R-induced PA dysfunction and a possible protective role of acute simvastatin pretreatment. MAIN METHODS: Male Wistar rats were subjected to occlusion of the superior mesenteric artery for 45 min followed by 2 h reperfusion (II/R) or sham-operated surgery (sham). In some rats, simvastatin (20 mg/kg, oral gavage) was administrated 1 h before II/R. KEY FINDINGS: II/R reduced acetylcholine-induced relaxation and phenylephrine-induced contraction of PA segments, which were prevented by acute simvastatin pretreatment in vivo or restored by inducible nitric oxide synthase (iNOS) inhibition in situ with 1400 W. Elevated reactive oxygen species (ROS) levels and higher nuclear translocation of nuclear factor kappa B (NFκB) subunit p65 were observed in PA of II/R rats and prevented by simvastatin. Moreover, simvastatin increased superoxide dismutase (SOD) activity and endothelial nitric oxide synthase (eNOS) expression in PA of the II/R group as well as prevented the increased levels of interleukin (IL)-1ß and IL-6 in lung explants following II/R. SIGNIFICANCE: The study suggests that pretreatment with a single dose of simvastatin prevents the II/R-induced increase of inflammatory factors and oxidative stress, as well as PA endothelial dysfunction and adrenergic hyporreactivity. Therefore, acute simvastatin administration could be therapeutic for pulmonary vascular disease in patients suffering from intestinal ischemic events.

Effects of ischemia and reperfusion on P2X2 receptor expressing neurons of the rat ileum enteric nervous system.

PURPOSE: We investigated the effects of ischemia/reperfusion in the intestine (I/R-i) on purine receptor P2X2-immunoreactive (IR) neurons of the rat ileum. METHODS: The superior mesenteric artery was occluded for 45 min with an atraumatic vascular clamp and animals were sacrificed 4 h later. Neurons of the myenteric and submucosal plexuses were evaluated for immunoreactivity against the P2X2 receptor, nitric oxide synthase (NOS), choline acetyl transferase (ChAT), calbindin, and calretinin. RESULTS: Following I/R-i, we observed a decrease in P2X2 receptor immunoreactivity in the cytoplasm and surface membranes of neurons of the myenteric and submucosal plexuses. These studies also revealed an absence of calbindin-positive neurons in the I/R-i group. In addition, the colocalization of the P2X2 receptor with NOS, ChAT, and calretinin immunoreactivity in the myenteric plexus was decreased following I/R-i. Likewise, the colocalization between P2X2 and calretinin in neurons of the submucosal plexus was also reduced. In the I/R-i group, there was a 55.8% decrease in the density of neurons immunoreactive (IR) for the P2X2 receptor, a 26.4% reduction in NOS-IR neuron, a 25% reduction in ChAT-IR neuron, and a 47% reduction in calretinin-IR neuron. The density of P2X2 receptor and calretinin-IR neurons also decreased in the submucosal plexus of the I/R-i group. In the myenteric plexus, P2X2-IR, NOS-IR, ChAT-IR and calretinin-IR neurons were reduced in size by 50%, 49.7%, 42%, and 33%, respectively, in the I/R-i group; in the submucosal plexus, P2X2-IR and calretinin-IR neurons were reduced in size by 56% and 72.6%, respectively. CONCLUSIONS: These data demonstrate that ischemia/reperfusion of the intestine affects the expression of the P2X2 receptor in neurons of the myenteric and submucosal plexus, as well as density and size of neurons in this population. Our findings indicate that I/R-i induces changes in P2X2-IR enteric neurons that could result in alterations in intestinal motility.

Respiratory mechanics during methacholine bolus and continuous infusion protocols in asthma model.

Balb/c mice respiratory mechanics was studied in two intravenous methacholine (MCh) protocols: bolus and continuous infusion. The Constant Phase Model (CPM) was used in this study. The harmonic distortion index (kd) was used to assess the respiratory system nonlinearity. The analysis of variance showed difference between groups (OVA vs control) and among doses for both protocols. Bolus protocol posttest: there was a difference between OVA and control at 0.3 and 1 mg/kg doses (p<0.0001 and p<0.001) for Rn. Infusion: there was a difference between OVA and control at 192 µg.kg-1.min-1 dose for Rn, G and H, (p<0.01; p<0.001; p<0.001). An increment was found in kd values near to the observed peak values in bolus protocol. The bolus protocol could better differentiate inflamed and non-inflamed airway resistance, whereas the differences between OVA and control in continuous infusion protocol were associated to airway- and, mainly, parenchyma-related parameters. Moreover, the bolus protocol presented a higher nonlinear degree compared to the infusion protocol.

Estradiol prevented intestinal ischemia and reperfusion-induced changes in intestinal permeability and motility in male rats.

OBJECTIVES: Ischemia and reperfusion (I/R) in the intestine could lead to severe endothelial injury, compromising intestinal motility. Reportedly, estradiol can control local and systemic inflammation induced by I/R injury. Thus, we investigated the effects of estradiol treatment on local repercussions in an intestinal I/R model. METHODS: Rats were subjected to ischemia via the occlusion of the superior mesenteric artery (45 min) followed by reperfusion (2h). Thirty minutes after ischemia induction (E30), 17ß-estradiol (E2) was administered as a single dose (280 µg/kg, intravenous). Sham-operated animals were used as controls. RESULTS: I/R injury decreased intestinal motility and increased intestinal permeability, accompanied by reduced mesenteric endothelial nitric oxide synthase (eNOS) and endothelin (ET) protein expression. Additionally, the levels of serum injury markers and inflammatory mediators were elevated. Estradiol treatment improved intestinal motility, reduced intestinal permeability, and increased eNOS and ET expression. Levels of injury markers and inflammatory mediators were also reduced following estradiol treatment. CONCLUSION: Collectively, our findings indicate that estradiol treatment can modulate the deleterious intestinal effects of I/R injury. Thus, estradiol mediates the improvement in gut barrier functions and prevents intestinal dysfunction, which may reduce the systemic inflammatory response.

Lung Edema and Mortality Induced by Intestinal Ischemia and Reperfusion Is Regulated by VAChT Levels in Female Mice.

Acute lung injury induced by intestinal ischemia/reperfusion (I/R) is a relevant clinical condition. Acetylcholine (ACh) and the α7 nicotinic ACh receptor (nAChRα-7) are involved in the control of inflammation. Mice with reduced levels of the vesicular ACh transporter (VAChT), a protein responsible for controlling ACh release, were used to test the involvement of cholinergic signaling in lung inflammation due to intestinal I/R. Female mice with reduced levels of VAChT (VAChT-KDHOM) or wild-type littermate controls (WT) were submitted to intestinal I/R followed by 2 h of reperfusion. Mortality, vascular permeability, and recruitment of inflammatory cells into the lung were investigated. Parts of mice were submitted to ovariectomy (OVx) to study the effect of sex hormones or treated with PNU-282,987 (nAChRα-7 agonist). A total of 43.4% of VAChT-KDHOM-I/R mice died in the reperfusion period compared to 5.2% of WT I/R mice. The I/R increased lung inflammation in both genotypes. In VAChT-KDHOM mice, I/R increased vascular permeability and decreased the release of cytokines in the lung compared to WT I/R mice. Ovariectomy reduced lung inflammation and permeability compared to non-OVx, but it did not avoid mortality in VAChT-KDHOM-I/R mice. PNU treatment reduced lung permeability, increased the release of proinflammatory cytokines and the myeloperoxidase activity in the lungs, and prevented the increased mortality observed in VAChT-KDHOM mice. Cholinergic signaling is an important component of the lung protector response against intestinal I/R injury. Decreased cholinergic signaling seems to increase pulmonary edema and dysfunctional cytokine release that increased mortality, which can be prevented by increasing activation of nAChRα-7.

A probiotic has differential effects on allergic airway inflammation in A/J and C57BL/6 mice and is correlated with the gut microbiome.

The phenotypes of allergic airway diseases are influenced by the interplay between host genetics and the gut microbiota, which may be modulated by probiotics. We investigated the probiotic effects on allergic inflammation in A/J and C57BL/6 mice. C57BL/6 mice had increased gut microbiota diversity compared to A/J mice at baseline. Acetate producer probiotics differentially modulated and altered the genus abundance of specific bacteria, such as Akkermansia and Allistipes, in mouse strains. We induced airway inflammation followed by probiotic treatment and found that only A/J mice exhibited decreased inflammation, and the beneficial effects of probiotics in A/J mice were partially due to acetate production. To understand the relevance of microbial composition colonization in the development of allergic diseases, we implanted female C57BL/6 mice with A/J embryos to naturally modulate the microbial composition of A/J mice, which increased gut microbiota diversity and reduced eosinophilic inflammation in A/J. These data demonstrate the central importance of microbiota to allergic phenotype severity. Video Abstract.

Female sex hormones mediate the allergic lung reaction by regulating the release of inflammatory mediators and the expression of lung E-selectin in rats.

BACKGROUND: Fluctuations of estradiol and progesterone levels caused by the menstrual cycle worsen asthma symptoms. Conflicting data are reported in literature regarding pro and anti-inflammatory properties of estradiol and progesterone. METHODS: Female Wistar rats were ovalbumin (OVA) sensitized 1 day after resection of the ovaries (OVx). Control group consisted of sensitized-rats with intact ovaries (Sham-OVx). Allergic challenge was performed by aerosol (OVA 1%, 15 min) two weeks later. Twenty four hours after challenge, BAL, bone marrow and total blood cells were counted. Lung tissues were used as explants, for expontaneous cytokine secretion in vitro or for immunostaining of E-selectin. RESULTS: We observed an exacerbated cell recruitment into the lungs of OVx rats, reduced blood leukocytes counting and increased the number of bone marrow cells. Estradiol-treated OVx allergic rats reduced, and those treated with progesterone increased, respectively, the number of cells in the BAL and bone marrow. Lungs of OVx allergic rats significantly increased the E-selectin expression, an effect prevented by estradiol but not by progesterone treatment. Systemically, estradiol treatment increased the number of peripheral blood leukocytes in OVx allergic rats when compared to non treated-OVx allergic rats. Cultured-BAL cells of OVx allergic rats released elevated amounts of LTB4 and nitrites while bone marrow cells increased the release of TNF-alpha and nitrites. Estradiol treatment of OVx allergic rats was associated with a decreased release of TNF-alpha, IL-10, LTB4 and nitrites by bone marrow cells incubates. In contrast, estradiol caused an increase in IL-10 and NO release by cultured-BAL cells. Progesterone significantly increased TNF- alpha by cultured BAL cells and bone marrow cells. CONCLUSIONS: Data presented here suggest that upon hormonal oscillations the immune sensitization might trigger an allergic lung inflammation whose phenotype is under control of estradiol. Our data could contribute to the understanding of the protective role of estradiol in some cases of asthma symptoms in fertile ans post-menopausal women clinically observed.

Local and remote tissue injury upon intestinal ischemia and reperfusion depends on the TLR/MyD88 signaling pathway.

Innate immune responses against microorganisms may be mediated by Toll-like receptors (TLRs). Intestinal ischemia-reperfusion (i-I/R) leads to the translocation of bacteria and/or bacterial products such as endotoxin, which activate TLRs leading to acute intestinal and lung injury and inflammation observed upon gut trauma. Here, we investigated the role of TLR activation by using mice deficient for the common TLR adaptor protein myeloid differentiation factor 88 (MyD88) on local and remote inflammation following intestinal ischemia. Balb/c and MyD88(-/-) mice were subjected to occlusion of the superior mesenteric artery (45 min) followed by intestinal reperfusion (4 h). Acute neutrophil recruitment into the intestinal wall and the lung was significantly diminished in MyD88(-/-) after i-I/R, which was confirmed microscopically. Diminished neutrophil recruitment was accompanied with reduced concentration of TNF-alpha and IL-1beta level. Furthermore, diminished microvascular leak and bacteremia were associated with enhanced survival of MyD88(-/-) mice. However, neither TNF-alpha nor IL-1beta neutralization prevented neutrophil recruitment into the lung but attenuated intestinal inflammation upon i-I/R. In conclusion, our data demonstrate that disruption of the TLR/MyD88 pathway in mice attenuates acute intestinal and lung injury, inflammation, and endothelial damage allowing enhanced survival.