endothelin-1 and Respiratory-Distress-Syndrome

Endothelin-1 (ET-1) is a 21 amino acid peptide with diverse biological activity that has been implicated in numerous diseases. ET-1 is a potent mitogen regulator of smooth muscle tone, and inflammatory mediator that may play a key role in diseases of the airways, pulmonary circulation, and inflammatory lung diseases, both acute and chronic. This review will focus on the biology of ET-1 and its role in lung disease.

Topics: Amino Acid Sequence; Endothelin-1; Graft Rejection; Humans; Lung; Lung Diseases; Lung Neoplasms; Lung Transplantation; Molecular Sequence Data; Respiratory Distress Syndrome; Respiratory Tract Diseases; Vascular Diseases

To compare hemodynamic and gasometric variables and the plasma concentrations of nitric oxide metabolites (cyclic guanosine monophosphate and nitrate and nitrite), endothelin-1, and renin-angiotensin metabolites before and after the start of nitric oxide inhalation, after prolonged nitric oxide inhalation, and before and after nitric oxide withdrawal.. Prospective study.. Surgical intensive care unit, university hospital.. Patients with acute lung injury and right ventricular failure.. Nitric oxide inhalation (10-12 ppm) during a median of 2.9 days (12 hrs to 6.5 days).. The pulmonary vasodilator effects of inhaled nitric oxide improved arterial oxygenation in patients with acute lung injury (p < .05) and reduced right atrial pressure in patients with right ventricular dysfunction (p < .01). These beneficial effects lasted the whole period of prolonged inhaled nitric oxide therapy up to 6.5 days. However, when inhaled nitric oxide was withdrawn, pulmonary vasodilator effects rapidly disappeared, and Pao2/Fio2 ratio markedly deteriorated in all studied patients to return to pre-inhaled nitric oxide levels. Changes in plasma cyclic guanosine monophosphate and nitrate and nitrite paralleled those of pulmonary vasodilatory effects. An immediate increase in plasma cyclic guanosine monophosphate with a slightly delayed increase in plasma nitrate and nitrite was observed at inhaled nitric oxide start with no attenuation during the prolonged inhaled nitric oxide therapy. A marked decrease toward pre-inhaled nitric oxide levels was seen within hours of inhaled nitric oxide withdrawal. In addition, no alteration of plasma endothelin-1 or renin-angiotensin mediators was observed during or after inhaled nitric oxide therapy.. Our study showed a lack of attenuation in the beneficial effects of inhaled nitric oxide and a lack of alteration of endogenous nitric oxide, endothelin-1, and renin-angiotensin pathways during prolonged nitric oxide inhalation.

Topics: Administration, Inhalation; Adult; Aged; Atrial Natriuretic Factor; Cyclic GMP; Endothelin-1; Endothelium-Dependent Relaxing Factors; Female; Humans; Intensive Care Units; Male; Middle Aged; Nitric Oxide; Respiratory Distress Syndrome; Ventricular Dysfunction, Right

To study the effects of infusion of atrial natriuretic peptide (ANP) versus the inhalation of nitric oxide (NO) in patients with an early acute respiratory distress syndrome (ARDS).. Ten patients with severe ARDS were studied in a crossover study design, within 72 hours after starting mechanical ventilation. We studied the effects of ANP infusion (10 ng/kg/min for 1 hour) and of inhalation of NO (20 ppm for 1 hour) on hemodynamic and respiratory patient parameters, as well as the effects on plasma levels of ANP, guanosine 3',5'-cyclic monophosphate, nitrate and endothelin-1.. Despite an approximate 50% increase in mixed venous ANP plasma concentration (from 86 +/- 21 to 123 +/- 33 ng/l, P < 0.05) during ANP infusion, there were no changes in mean pulmonary artery pressure, pulmonary vascular resistance index, extravascular lung water index, or in pulmonary gas exchange. NO inhalation, in contrast, lowered mean pulmonary artery pressure (from 26 +/- 1.9 to 23.9 +/- 1.7 mmHg, P < 0.01), pulmonary vascular resistance index (from 314 +/- 37 to 273 +/- 32 dynes/cm5/m2, P < 0.05) and central venous pressure (from 8.2 +/- 1.2 to 7.3 +/- 1.1 mmHg, P < 0.02). Furthermore, NO inhalation improved pulmonary gas exchange, reflected by a decrease in alveolar-arterial oxygen gradient (from 41.9 +/- 3.9 to 40.4 +/- 3.6 kPa, P < 0.05), a small increase in oxygenation (PaO2/FiO2 from 17.7 +/- 1.4 to 19.7 +/- 1.1 kPa, P = 0.07) and a small decrease in venous admixture (Qs/Qt from 35.7 +/- 2.0 to 32.8 +/- 2.7%, P = 0.11).. This study shows that, in contrast to NO inhalation, infusion of ANP neither improves oxygenation nor attenuates pulmonary hypertension or pulmonary edema in patients with severe ARDS.

Topics: Administration, Inhalation; Adult; Aged; Atrial Natriuretic Factor; Cross-Over Studies; Cyclic GMP; Endothelin-1; Female; Hemodynamics; Humans; Infusions, Intravenous; Male; Middle Aged; Nitrates; Nitric Oxide; Pulmonary Gas Exchange; Respiration, Artificial; Respiratory Distress Syndrome; Vasodilator Agents

Pulmonary exposure to the plant toxin ricin leads to respiratory insufficiency and death. To date, in-depth study of acute respiratory distress syndrome (ARDS) following pulmonary exposure to toxins is hampered by the lack of an appropriate animal model. To this end, we established the pig as a large animal model for the comprehensive study of the multifarious clinical manifestations of pulmonary ricinosis. Here, we report for the first time, the monitoring of barometric whole body plethysmography for pulmonary function tests in non-anesthetized ricin-treated pigs. Up to 30 h post-exposure, as a result of progressing hypoxemia and to prevent carbon dioxide retention, animals exhibited a compensatory response of elevation in minute volume, attributed mainly to a large elevation in respiratory rate with minimal response in tidal volume. This response was followed by decompensation, manifested by a decrease in minute volume and severe hypoxemia, refractory to oxygen treatment. Radiological evaluation revealed evidence of early diffuse bilateral pulmonary infiltrates while hemodynamic parameters remained unchanged, excluding cardiac failure as an explanation for respiratory insufficiency. Ricin-intoxicated pigs suffered from increased lung permeability accompanied by cytokine storming. Histological studies revealed lung tissue insults that accumulated over time and led to diffuse alveolar damage. Charting the decline in PaO2/FiO2 ratio in a mechanically ventilated pig confirmed that ricin-induced respiratory damage complies with the accepted diagnostic criteria for ARDS. The establishment of this animal model of pulmonary ricinosis should help in the pursuit of efficient medical countermeasures specifically tailored to deal with the respiratory deficiencies stemming from ricin-induced ARDS.

Topics: Animals; Blood Cell Count; Body Temperature; Bronchoalveolar Lavage Fluid; Cytokines; Disease Models, Animal; Endothelin-1; Female; Hydrogen-Ion Concentration; Inflammation Mediators; Lung; Lung Injury; Oxygen; Partial Pressure; Permeability; Pneumonia; Pulmonary Gas Exchange; Respiratory Distress Syndrome; Respiratory Function Tests; Ricin; Swine

Acute respiratory distress syndrome (ARDS) is characterized by inflammatory injury to the alveolar and capillary barriers that results in impaired gas exchange and severe acute respiratory failure. Nuclear orphan receptor Nur77 has emerged as a regulator of gene expression in inflammation, and its role in the pathogenesis of ARDS is not clear. The objective of this study is to investigate the potential role of Nur77 and its underlying mechanism in the regulation of endothelin-1 (ET-1) expression in lipopolysaccharide (LPS)-induced A549 cells and an ARDS rat model. We demonstrate that LPS induced Nur77 expression and nuclear export in A549 cells. Overexpression of Nur77 markedly decreased basal and LPS-induced ET-1 expression in A549 cells, whereas knockdown of Nur77 increased the ET-1 expression. LPS-induced phosphorylation and nuclear translocation of NF-κB and p38 MAPK were blocked by Nur77 overexpression and augmented by Nur77 knockdown in A549 cells. In vivo, LPS induced Nur77 expression in lung in ARDS rats. Pharmacological activation of Nur77 by cytosporone B (CsnB) inhibited ET-1 expression in ARDS rats, decreased LPS-induced phosphorylation of NF-κB and p38 MAPK, and relieved lung, liver, and kidney injury. Pharmacological deactivation of Nur77 by 1,1-bis-(3'-indolyl)-1-(p-hydroxyphenyl)methane (DIM-C-pPhOH, C-DIM8) had no effect on ET-1 expression and lung injury. These results indicated that Nur77 decreases ET-1 expression by suppressing NF-κB and p38 MAPK in LPS-stimulated A549 cells in vitro, and, in an LPS-induced ARDS rat model, CsnB reduced ET-1 expression and lung injury in ARDS rats.

Topics: A549 Cells; Active Transport, Cell Nucleus; Animals; Cell Nucleus; Disease Models, Animal; Down-Regulation; Endothelin-1; Kidney; Lipopolysaccharides; Liver; Lung; Male; NF-kappa B; Nuclear Receptor Subfamily 4, Group A, Member 1; p38 Mitogen-Activated Protein Kinases; Phenylacetates; Rats, Sprague-Dawley; Respiratory Distress Syndrome; RNA, Messenger

Inhaled nitric oxide (INO) improves ventilation-perfusion matching and alleviates pulmonary hypertension in patients with acute respiratory distress syndrome. However, outcome has not yet been shown to improve, and nonresponse is common. A better understanding of the mechanisms by which INO acts may guide in improving treatment with INO in patients with severe respiratory failure. We hypothesized that INO may act not only by vasodilation in ventilated lung regions, but also by causing vasoconstriction via endothelin (ET-1) in atelectatic, nonventilated lung regions. This was studied in 30 anesthetized, mechanically ventilated piglets. The fall in oxygenation and rise in pulmonary artery pressure during a sepsislike condition (infusion of endotoxin) were blunted by INO 40 ppm. Endotoxin infusion increased serum ET-1, and INO almost doubled the ratio between mRNA expression of endothelin receptor A (mediating vasoconstriction) and B (mediating vasodilation and clearance of ET-1) (ET-A/ET-B) in atelectatic lung regions. INO caused a shift in blood flow away from atelectatic lung regions in the endotoxemic piglets, but not during ET receptor antagonism. We conclude that INO in short-term experiments, in addition to causing selective pulmonary vasodilation in ventilated lung regions, increases the ET-A/ET-B mRNA expression ratio in lung tissue. This might augment the vasoconstriction in atelectatic lung regions, enhancing the redistribution of pulmonary blood flow to ventilated lung regions which are reached by INO. Such vasoconstriction may be an important additional factor explaining the effect of INO.

Topics: Administration, Inhalation; Animals; Blood Pressure; Endothelin Receptor Antagonists; Endothelin-1; Endotoxins; Hypertension, Pulmonary; Lung; Lung Injury; Nitric Oxide; Pulmonary Circulation; Receptors, Endothelin; Respiration; Respiration, Artificial; Respiratory Distress Syndrome; RNA, Messenger; Swine; Vasoconstriction

There have been contradictory reports suggesting that CO(2) may constrict, dilate, or have no effect on pulmonary vessels. Permissive hypercapnia has become a widely adopted ventilatory technique used to avoid ventilator-induced lung injury, particularly in patients with acute respiratory distress syndrome (ARDS). On the other hand, respiratory alkalosis produced by mechanically induced hyperventilation is the mainstay of treatment for newborn infants with persistent pulmonary hypertension. It is important to clarify the vasomotor effect of CO(2) on pulmonary circulation in order to better evaluate the strategies of mechanical ventilation in intensive care. In the present study, pulmonary vascular responses to CO(2) were observed in isolated rat lungs (n = 32) under different levels of pulmonary arterial pressure (PAP) induced by various doses of endothelin-1 (ET-1). The purposes of this study were to investigate (1) the vasodilatory effect of 5% CO(2) in either N(2) (hypoxic-hypercapnia) or air (normoxic-hypercapnia) at different PAP levels induced by various doses of endothelin-1, and (2) the role of nitric oxide (NO) in mediating the pulmonary vascular response to hypercapnia, hypoxia, and ET-1. The results indicated that (1) CO(2) produces pulmonary vasodilatation at high PAP under ET-1 and hypoxic vasoconstriction; (2) the vasodilatory effect of CO(2) at different pressure levels varies in accordance with the levels of PAP, the dilatory effect tends to be more evident at higher PAP; and (3) endogenous NO attenuates ET-1 and hypoxic pulmonary vasoconstriction but does not augment the CO(2)-induced vasodilatation.

Topics: Animals; Blood Pressure; Carbon Dioxide; Endothelin B Receptor Antagonists; Endothelin-1; Hypertension, Pulmonary; In Vitro Techniques; Male; Nitric Oxide; Pulmonary Artery; Pulmonary Circulation; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Vasodilation

Endothelin-1 (ET-1) is increased in patients with high-altitude pulmonary edema and acute respiratory distress syndrome, and these patients have decreased alveolar fluid reabsorption (AFR).. To determine whether ET-1 impairs AFR via activation of endothelial cells and nitric oxide (NO) generation.. Isolated perfused rat lung, transgenic rats deficient in ETB receptors, coincubation of lung human microvascular endothelial cells (HMVEC-L) with rat alveolar epithelial type II cells or A549 cells, ouabain-sensitive 86Rb+ uptake.. The ET-1-induced decrease in AFR was prevented by blocking the endothelin receptor ETB, but not ETA. Endothelial-epithelial cell interaction is required, as direct exposure of alveolar epithelial cells (AECs) to ET-1 did not affect Na,K-ATPase function or protein abundance at the plasma membrane, whereas coincubation of HMVEC-L and AECs with ET-1 decreased Na,K-ATPase activity and protein abundance at the plasma membrane. Exposing transgenic rats deficient in ETB receptors in the pulmonary vasculature (ET-B(-/-)) to ET-1 did not decrease AFR or Na,K-ATPase protein abundance at the plasma membrane of AECs. Exposing HMVEC-L to ET-1 led to increased NO, and the ET-1-induced down-regulation of Na,K-ATPase was prevented by the NO synthase inhibitor l-NAME, but not by a guanylate cyclase inhibitor.. We provide the first evidence that ET-1, via an endothelial-epithelial interaction, leads to decreased AFR by a mechanism involving activation of endothelial ETB receptors and NO generation leading to alveolar epithelial Na,K-ATPase down-regulation in a cGMP-independent manner.

Topics: Adenosine Triphosphatases; Animals; Cyclic GMP; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; Extravascular Lung Water; Female; Humans; In Vitro Techniques; Lung Injury; Male; Nitric Oxide; Pulmonary Alveoli; Rats; Rats, Transgenic; Receptor, Endothelin A; Receptor, Endothelin B; Respiratory Distress Syndrome

To analyze the effect of endothelin-1 on pulmonary arterial and venous contractile force in vitro and on up- and downstream pulmonary vascular resistance in vivo under sham and endotoxemic conditions in pigs.. In vitro: paired preparations of pulmonary arteries and veins were mounted in a myograph (n=13) for measurements of contractile responses to increasing concentrations of phenylephrine, endothelin-1, and sarafotoxin (endothelin receptor type B agonist). In vivo: 20 pigs were anesthetized, mechanically ventilated, and subjected to phenylephrine (reference substance), endothelin-1, sarafotoxin, endotoxin, and tezosentan (dual endothelin receptor antagonist). Hemodynamic and gas-exchange variables were monitored. Pulmonary capillary pressure, used for calculation of upstream and downstream vascular resistance, was assessed by the pulmonary vascular occlusion technique.. Pulmonary veins were more sensitive than arteries to endothelin-1 both in vitro and in vivo. This difference was more pronounced with sarafotoxin, where almost no arterial effects were noted. In vivo and in vitro exposure to phenylephrine resulted in selective arterial constriction. Endotoxin infusion resulted in pulmonary hypertension with a clear downstream dominance. The latter changes including the increase in capillary pressure were totally abolished by intervention with the dual endothelin receptor antagonist tezosentan.. The endothelin system is extensively involved in endotoxemic pulmonary venous hypertension, an effect possibly mediated by the endothelin B receptor.

Topics: Animals; Ciprofloxacin; Endothelin-1; Female; Hypertension, Pulmonary; Lipopolysaccharides; Lung; Male; Pyridines; Respiratory Distress Syndrome; Sepsis; Swine; Tetrazoles; Vascular Resistance; Vasoconstriction; Vasodilator Agents

Phosphoramidon blocks the formation of endothelin-1 (ET-1), a proinflammatory mediator implicated in the pathogenesis of a variety of lung diseases. To determine whether phosphoramidon can ameliorate pulmonary inflammation, our laboratory undertook a series of experiments involving treatment of hamsters with either intraperitoneal (i.p.) or aerosolized phosphoramidon prior to induction of acute lung injury by intratracheal administration of lipopolysaccharide (LPS). The results indicate that phosphoramidon significantly reduces LPS-induced pulmonary inflammation as measured by lung histology, neutrophil content of bronchoalveolar lavage (BAL) fluid, percent tumor necrosis factor receptor 1 (TNFR1)-labeled BAL macrophages, and alveolar septal cell apoptosis. In additional experiments, i.p. administration of a novel endothelin A receptor anatgonist (HJP272) similarly decreased BAL neutrophils, whereas i.p. administration of either ET-1, or its precursor peptide, "big" ET-1, had the opposite effect. These findings support further evaluation of phosphoramidon and other ET-1 suppressors as potential treatments for human inflammatory lung disease.

Topics: Animals; Apoptosis; Cricetinae; Endothelin A Receptor Antagonists; Endothelin-1; Glycopeptides; Lipopolysaccharides; Lung; Mesocricetus; Receptors, Tumor Necrosis Factor, Type I; Respiratory Distress Syndrome

Endothelin-1 (ET-1), a potent vasoconstrictor peptide produced by endothelial cells, has been implicated in the dysfunction of various organs. To determine the role of ET-1 in acute lung injury (ALI) and ARDS, ET-1 levels were measured in epithelial lining fluid (ELF) and plasma obtained from patients with ALI/ARDS.. A cross-sectional study of patients with ALI/ARDS in the intensive care unit of two university hospitals was performed. Patients with ALI/ARDS underwent bronchoscopic microsampling to collect ELF on the day of onset of the disease. Patients who underwent bronchoscopy to examine a small peripheral pulmonary nodule served as controls.. In the 23 patients with ALI/ARDS, the ET-1 level in ELF was significantly greater than that in plasma (P < 0.001). In contrast, ET-1 was not detectable in the ELF from six of the seven control subjects. The albumin concentration of ELF, used as a marker of endothelial and epithelial permeability, correlated with the ET-1 level in ELF (P < 0.001). The oxygenation index (PaO(2)/FiO(2)) was also correlated with ET-1 concentration in ELF (P < 0.001).. In patients with ALI/ARDS, ET-1 is produced mainly in the lung and is associated not only with pulmonary vasoconstriction but also the development of permeability oedema, leading to the impairment of oxygenation.

Topics: Aged; Aged, 80 and over; Albumins; Bronchoscopy; Colorimetry; Cross-Sectional Studies; Endothelin-1; Female; Humans; Male; Middle Aged; Respiratory Distress Syndrome

To test the hypothesis that the endothelin system is involved in chlorine gas-induced lung injury.. Experimental study.. Academic research laboratory.. Twenty-four domestic juvenile pigs.. Anesthetized, ventilated pigs were exposed to chlorine gas (400 parts per million in air) for 20 mins and then randomly allocated to four groups (n=6 in each group). The tezosentan pretreatment group received the dual endothelin receptor antagonist tezosentan 20 mins before and hyperoxic gas (Fio2 0.6) after chlorine gas exposure. The tezosentan postinjury treatment group received hyperoxic gas after chlorine gas exposure and tezosentan 60 mins later. Animals in the oxygen group received hyperoxic gas after chlorine gas exposure. Pigs in the fourth group (air) were ventilated with room air (Fio2 0.21) throughout the experiment.. Hemodynamics, gas exchange, lung mechanics, and plasma endothelin-1 were evaluated for 6 hrs. Chlorine gas exposure induced an increase in circulating endothelin-1 by 90% (p<.05). The acute chlorine gas-induced rise in pulmonary vascular resistance was partly blocked by tezosentan pretreatment (p<.001). Tezosentan postinjury treatment also decreased pulmonary vascular resistance to levels significantly lower than in the air and oxygen groups (p<.001). Recovery of peak airway pressure was better in the tezosentan-treated groups than in the air group. There were significant linear relationships between circulating endothelin-1 and pulmonary vascular resistance (r=.47, p<.001) and endothelin-1 and peak airway pressure (r=.41, p<.001). These relationships were modified by tezosentan.. Tezosentan modified chlorine gas-induced pulmonary dysfunction, indicating that the endothelin system is involved in this mode of acute lung injury.

Topics: Animals; Chlorine; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Female; Lung Compliance; Pyridines; Respiratory Distress Syndrome; Swine; Tetrazoles; Treatment Outcome; Vascular Resistance; Vasodilator Agents

To find out if the extravascular lung water index (EVLWI) and the derived permeability indexes determined by the single transpulmonary thermodilution technique are associated with markers of acute lung injury in human septic shock.. Prospective, observational study.. Mixed intensive care unit of a 900-bed university hospital.. Thirty-eight consecutive adult patients with septic shock and acute lung injury.. None.. The variables were assessed over a 72-hr period and included hemodynamics, EVLWI, and pulmonary vascular permeability indexes determined with the single indicator transpulmonary thermodilution technique, lung compliance, oxygenation ratio (Pao2/Fio2), lung injury score, cell counts, and the plasma concentration of endothelin-1. At day 1, EVLWI was elevated (>or=7 mL/kg) in 28 (74%) patients and correlated with lung compliance (r=-.48, p=.002), Pao2/Fio2 (r=-.50, p=.001), lung injury score (r=.46, p=.004), roentgenogram quadrants (r=.39, p=.02), and platelet count (r=-.43, p=.007). At day 3, EVLWI correlated with compliance (r=-.51, p=.002), Pao2/Fio2 (r=-.49, p = .006), and lung injury score (r=.53, p=.003). At day 3, EVLWI and pulmonary vascular permeability indexes were higher in nonsurvivors (p<.05). The plasma concentration of endothelin-1 (mean+/-sd) was significantly higher in patients with elevated EVLWI (>or=7 mL/kg) (3.85+/-1.40 vs. 2.07+/-0.38 pg/mL, respectively). Twenty-two (59%) patients died before day 28.. In human septic shock, EVLWI demonstrated moderate correlation with markers of acute lung injury, such as lung compliance, oxygenation ratio, roentgenogram quadrants, and lung injury score. In nonsurvivors, EVLWI and permeability indexes were significantly increased at day 3. Thus, EVLWI might be of value as an indicator of prognosis and severity of sepsis-induced acute lung injury.

Topics: Biomarkers; Endothelin-1; Extravascular Lung Water; Female; Follow-Up Studies; Humans; Lung Compliance; Male; Middle Aged; Prognosis; Prospective Studies; Respiratory Distress Syndrome; Severity of Illness Index; Shock, Septic; Thermodilution

Topics: Administration, Inhalation; Cardiac Output; Endothelin-1; Free Radical Scavengers; Humans; Muscle, Smooth, Vascular; Nitric Oxide; Respiratory Distress Syndrome

Studies in vitro reveal that endothelin-1 (ET-1) activates the alpha isoform of protein kinase C (PKC-alpha) in cultures of endothelial cells, thereby deranging cellular integrity. Sepsis and endotoxemia are associated with increased plasma concentrations of ET-1 that induce acute lung injury (ALI). We recently reported that non-selective ET-1 receptor blockade attenuates ALI in sheep by reducing the endotoxin-induced increase in extravascular lung water index (EVLWI). The aim of this study was to find out whether this attenuation is associated with reduced translocation of PKC-alpha from the cytosolic to the membrane fraction of lung tissue homogenate.. Seventeen awake, instrumented sheep were randomly assigned to a sham-operated group (n = 3), a lipopolysaccharide (LPS) group (n = 7) receiving an intravenous infusion of Escherichia coli 15 ng/kg per min for 24 hours, and a tezosentan group (n = 7) subjected to LPS and, from 4 hours, an intravenous injection of tezosentan 3 mg/kg followed by infusion at 1 mg/kg per hour for the reminder of the experiment. Pulmonary micro-occlusion pressure (Pmo), EVLWI, plasma concentrations of ET-1, tumor necrosis factor-a (TNF-a), and interleukin-8 (IL-8) were determined every 4 hours. Western blotting was used to assess PKC-alpha.. In non-treated sheep a positive correlation was found between the plasma concentration of ET-1 and Pmo in the late phase of endotoxemia (12 to 24 hours). A positive correlation was also noticed between Pmo and EVLWI in the LPS and the LPS plus tezosentan groups, although the latter was significantly reduced in comparison with LPS alone. In both endotoxemic groups, plasma concentrations of ET-1, TNF-alpha, and IL-8 increased. In the LPS group, the cytosolic fraction of PKC-alpha decreased by 75% whereas the membrane fraction increased by 40% in comparison with the sham-operated animals. Tezosentan completely prevented the changes in PKC-alpha in both the cytosolic and the membrane fractions, concomitantly causing a further increase in the plasma concentrations of ET-1, TNF-alpha, and IL-8.. In endotoxemic sheep, ET-1 receptor blockade alleviates lung injury as assessed by a decrease in EVLWI paralleled by a reduction in Pmo and the prevention of activation of PKC-alpha.

Topics: Animals; Endothelin A Receptor Antagonists; Endothelin-1; Endotoxemia; Enzyme Activation; Escherichia coli Infections; Interleukin-8; Protein Kinase C; Pyridines; Respiratory Distress Syndrome; Sheep; Tetrazoles; Tumor Necrosis Factor-alpha; Vasodilator Agents

Ischemia-reperfusion (I/R) injury of the lung involves increased pulmonary vascular resistance. Prostaglandins are thought to have a beneficial effect in lung transplantation, but their mechanism in I/R injury is unknown. We investigated whether iloprost, a stable prostacyclin analogue, prevents I/R-associated pulmonary vascular dysfunction and whether it affects endothelin-1 (ET-1) balance.. In an isolated blood-perfusion model, we subjected lungs of Lewis rats to 45 minutes of ischemia at 37 degrees C and randomly allocated the lungs to 3 groups (n = 6 each): iloprost (33.3 nmol/liter) added to the perfusate before ischemia and reperfusion (ILO+IR), iloprost (33.3 nmol/liter) given only before reperfusion (ILO+R), and controls without iloprost treatment (ILO-).. Reperfusion induced marked pulmonary edema in non-treated controls (ILO-), which was attenuated in ILO+R lungs and completely prevented in ILO+IR lungs. At 60 minutes reperfusion, arterial oxygen tension was significantly greater in both ILO+R and ILO+IR lungs compared with ILO- controls. Mean pulmonary artery pressure and pulmonary vascular resistance were slightly decreased in the ILO+R and significantly decreased in the ILO+IR group compared with the ILO- controls. Plasma levels of big ET-1, measured in both afferent and efferent blood, showed that I/R results in increased pulmonary venous levels of big ET-1. Interestingly, the increased venoarterial ET-1 gradient in ILO- lungs decreased significantly in the ILO+IR group.. We demonstrated in an isolated lung perfusion model that iloprost ameliorates post-ischemic lung reperfusion injury and maintains an appropriate pulmonary ET-1 balance.

Topics: Animals; Body Weight; Disease Models, Animal; Endothelin-1; Iloprost; Lung; Male; Models, Cardiovascular; Oxygen; Pulmonary Circulation; Pulmonary Edema; Pulmonary Gas Exchange; Pulmonary Wedge Pressure; Rats; Rats, Inbred Lew; Reperfusion Injury; Respiratory Distress Syndrome; Severity of Illness Index; Statistics as Topic; Vascular Resistance; Vasodilator Agents

To investigate the effect of Ginkgo biloba extract (GBE) on acute lung injury(ALI) induced by lipopolysaccharide (LPS) in aging rats.. The rats were randomly divided into two parts: six rats served as normal controls; 18 rats were used for producing the aging animal model ( D-gal 50 mg/kg body weight was injected intraperitoneally, once a day for 6 weeks). The aging rats were then randomly divided into 3 groups: 6 rats as the aging control group; another 6 as the LPS treated aging group (LPS,5 mg/kg body weight intravenous injection); and the third as the GBE+LPS group (6 rats, GBE was started 7 days before the experiment,given once a day via the esophagus, the amount of flavone glycosides administered being 8 mg/kg body weight, and on the day of experiment, one dose of GBE was given 2 hours before LPS administration ). The samples were collected 2 hours after LPS or saline administration.. Compared with normal controls, the SOD activity in red cells and the Na(+) -K(+) -ATPase activity in the lung tissue decreased markedly (all P < 0.05), but the LDH activity increased (P < 0.05) in the aging rats. ALI was observed in the aging rats 2 hours after LPS administration. Compared with the aging control, in the LPS treated rats, there were more inflammatory cells in the lung tissue; protein content in bronchial alveolar lavage fluid (BALF) and the pulmonary permeability index (PPI) increased significantly (all P < 0.001); LD, MDA, NO(2) (-)/NO(3)(-), ET-1 and TNF-alpha content and LDH activity in blood, and MPO activity in lung tissue all increased significantly. On the contrary, SOD activity in red cells and Na(+) -K(+) -ATPase activity in lung tissue decreased markedly (P < 0.05, P < 0.01). These changes, except SOD, were markedly attenuated in the GBE+LPS rats.. The anti-oxidant activity was decreased in D-gal-induced aging rats. Intravenous administration of LPS caused acute lung injury in aging rats. GBE had protective effect on ALI induced by LPS.

Topics: Aging; Animals; Disease Models, Animal; Endothelin-1; Galactose; Ginkgo biloba; Lipopolysaccharides; Male; Nitrates; Nitrites; Plant Extracts; Protective Agents; Rats; Rats, Wistar; Respiratory Distress Syndrome; Sodium-Potassium-Exchanging ATPase; Superoxide Dismutase

We recently showed that pulmonary endothelins may affect coronary circulation under various experimental and clinical conditions. Here, we investigated the effect of pulmonary mediators on coronary tone in experimental acute respiratory distress syndrome. We focused particularly on pulmonary endothelin-1, a major vasoconstrictor in acute respiratory distress syndrome, and on adrenomedullin, a potent vasodilator that is up-regulated by inflammatory stimuli.. Controlled experiment that used isolated organs.. Experimental laboratory.. Wistar rats.. The saline effluent from an isolated lung was used to serially perfuse the coronary vessels of an isolated heart. We compared serial perfusion after 2-hr pretreatment of lungs with vehicle or endotoxin (50 microg/mL), and we used the following drugs to elucidate the coronary response observed: the endothelin type A receptor antagonist BQ-123 (2 microM), the endothelin type B antagonist A-192621 (500 nM), the endothelin-converting enzyme inhibitor phosphoramidon (50 microM), the calcitonin gene-related peptide type-1 receptor antagonist hCGRP(8-37) (2 microM), and the adrenomedullin receptor antagonist hAM(22-52) (200 nM) (n = 6 each).. In controls, serial perfusion decreased coronary flow to 87 +/- 3% of baseline (p < .05). BQ-123 and phosphoramidon prevented this effect, whereas blockade of endothelin type B and adrenomedullin-binding receptors had no effect. After endotoxin challenge, coronary flow significantly increased to 110 +/- 2%. This response was augmented by BQ-123 (124 +/- 2%) and phosphoramidon (123 +/- 3%); A-192621 had no effect. Application of hCGRP(8-37) and hAM(22-52) significantly decreased coronary flow to 81 +/- 3% and 88 +/- 2%, respectively. Flow decrease after blockade of both adrenomedullin-binding receptors (73 +/- 2%) significantly deteriorated peak left ventricular pressure, to 82 +/- 6% of baseline; rate of pressure increase, to 81 +/- 5%; and rate of pressure decline, to 77 +/- 6%. Endotoxin pretreatment elevated pulmonary venous big endothelin-1 (three-fold), endothelin-1 (two-fold), and adrenomedullin (five-fold).. In experimental acute respiratory distress syndrome, pulmonary adrenomedullin--via calcitonin gene-related peptide type-1 receptor and adrenomedullin receptor--outweighs the coronary vasoconstrictor impact of pulmonary big endothelin-1 exerted via endothelin type A receptors after conversion to mature endothelin-1. The consequence is prevention of flow-related deterioration of myocardial performance.

Topics: Adrenomedullin; Analysis of Variance; Animals; Antihypertensive Agents; Coronary Circulation; Endothelin Receptor Antagonists; Endothelin-1; Myocardial Contraction; Peptides; Peptides, Cyclic; Radioimmunoassay; Rats; Rats, Wistar; Receptors, Calcitonin Gene-Related Peptide; Respiratory Distress Syndrome

Recent studies have indicated effectiveness of glucocorticoid (GC) treatment in late, fibroproliferative adult respiratory distress syndrome. There is furthermore growing evidence for a role of endothelin-1 (ET-1) in lung fibroproliferation, but the impact of GC on stimulated pulmonary ET-1 is not well defined.. Prospective study in an experimental laboratory.. Male Wistar rats.. Isolated lungs were perfused over 120 min in recirculatory mode in presence of vehicle, interleukin-1 beta (IL-1 beta; 5 ng/ml) plus tumor necrosis factor-alpha (TNF-alpha; 5 ng/ml), dexamethasone (Dx; 1 nmol/l), Dx (10 nmol/l), IL-1 beta plus TNF alpha plus Dx 1, or IL-1 beta plus TNF alpha plus Dx 10 (n = 6 each). Pulmonary artery endothelial cells were stimulated over 30 min using a similar protocol.. Control lungs released 15.2 +/- 0.6 pg/ml big ET-1 and 0.46 +/- 0.06 pg/ml ET-1, and contained 0.73 +/- 0.05 ng/g wet weight (ww) big ET-1 and 3.06 +/- 0.22 ng/g ww ET-1. IL-1 beta plus TNF-alpha increased release of big ET-1 and ET-1, to 220% and 217%, and lung content of peptides, to 236% and 230%. Dx dose-dependently inhibited the cytokine-induced rise in peptide release and lung content and completely suppressed these effects at 10 nmol/l. Electrophoretic mobility shift assays with nuclear extracts of pulmonary artery endothelial cells demonstrated nuclear binding of the transcription factor nuclear factor kappa B in response to IL-1 beta plus TNF-alpha, which was decreased in presence of Dx 1 and Dx 10.. GC inhibit the cytokine-induced upregulation of pulmonary vascular and tissue endothelins, possibly via nuclear factor kappa B dependent mechanisms. This finding may reinforce the therapeutic employment of GC in late ARDS.

Topics: Animals; Cytokines; Dexamethasone; Disease Models, Animal; Endothelin-1; Endothelium, Vascular; Glucocorticoids; Hemodynamics; Male; NF-kappa B; Prospective Studies; Pulmonary Artery; Rats; Rats, Wistar; Respiratory Distress Syndrome

To investigate whether adenosine protects against endotoxin-induced increments in extravascular lung water content.. Prospective, randomized, animal study.. University research laboratory.. Twenty-one anesthetized juvenile pigs.. The animals were divided into two groups subjected to endotoxin infusion: Endotoxin alone (n = 7), or endotoxin combined with adenosine infusion (n = 7) administered during the whole experimental period. Two other groups were exposed to anesthesia alone (n = 4) or adenosine infusion alone (n = 3), respectively.. Central hemodynamic variables and extravascular lung water, as assessed by the thermal dye dilution double indicator technique, were monitored. Plasma endothelin-1 concentrations were measured hourly. Extravascular lung water increased significantly in response to endotoxemia (p <.001) along with an increase in pulmonary microvascular pressure (P(mv) [p <.01]). Although the Pmv increased less in endotoxemic animals exposed to adenosine infusion, no intergroup difference was found. From 4 through 6 hrs, adenosine-treated pigs displayed only half of the extravascular lung water content of nontreated animals (p <.01). The latter did not differ from that of anesthetized controls receiving anesthesia or adenosine alone. Adenosine administered alone had no effect on P(mv). In pigs receiving adenosine alone, extravascular lung water content reached nadir after 3 hrs. In both endotoxin groups, plasma endothelin-1 concentration increased two-fold, peaking 4-6 hrs after the start of endotoxin infusion (p <.001).. The endotoxin-induced increase in lung extravascular water was hampered by intravenously infused adenosine in the presence of a nonsignificantly reduced microvascular pressure. This leaves reduced microvascular permeability the most likely reason for the beneficial effect of adenosine.

Topics: Adenosine; Analysis of Variance; Animals; Blood Pressure; Capillary Permeability; Endothelin-1; Endotoxemia; Escherichia coli Infections; Extravascular Lung Water; Hemodynamics; Lung; Microcirculation; Pulmonary Gas Exchange; Random Allocation; Respiratory Distress Syndrome; Swine; Vasodilator Agents

Increased nitric oxide (NO) synthesis by the inducible nitric oxide synthase (iNOS) has been shown to contribute to the development of acute lung injury and delayed hypotension in animals injected with bacterial lipopolysaccharides (LPS). Recent evidence indicates that endothelin-1 (ET-1) is also elevated in septic humans and in animals. To assess the contribution of ETs to LPS-induced pulmonary NO production and iNOS expression, we used P1/fl, a 22 amino acid peptide, to selectively antagonize endothelin-A receptors. Anesthetized, mechanically ventilated rats were injected with either saline or LPS (E. coli endotoxin, 20 mg/kg) and studied for 5 h. Two other groups of rats were pretreated 15 min earlier with P1/fl peptide (20 microg/kg). Unlike saline-treated rats, rats injected with LPS showed a progressive decline in arterial pressure and a significant rise in plasma ET concentration and serum nitrite-nitrate level. In the lungs, LPS injection elicited a several-fold rise in lung iNOS activity and exhaled NO concentration and increased lung wet/dry ratio significantly. Pretreatment with P1/fl peptide eliminated the decline in arterial pressure, the rise in lung wet/dry ratio, lung NOS activity, and iNOS protein expression and significantly attenuated the increase in pulmonary exhaled NO production but had no effect on plasma ET concentration. We conclude that activation of ET-A receptors by rising ET-1 concentration enhances NO production and iNOS expression in the respiratory and vascular systems and contributes to both LPS-induced hypotension and acute lung injury.

Topics: Animals; Endothelin Receptor Antagonists; Endothelin-1; Escherichia coli; Intercellular Signaling Peptides and Proteins; Lipopolysaccharides; Lung; Male; Nitric Oxide; Nitric Oxide Synthase; Peptides; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Receptors, Endothelin; Respiratory Distress Syndrome

In patients with acute respiratory distress syndrome (ARDS), the prone position may enhance oxygenation by changing ventilation/perfusion ratio. In this study, we investigated whether the prone position affects the net balance between pulmonary endothelin (ET-1) and angiotensin II (Ang II) production and clearance, two metabolic functions of lung endothelial cells.. Anaesthesiological intensive care unit of a university hospital.. Ten ARDS patients (Murray score > 2.5) were studied in both the supine position (SP) and the prone position (PP). MEASUREMENTS AND DESIGN: Blood samples were taken simultaneously from the patient in SP for assessment of mixed venous and arterial ET-1 and Ang II concentrations, and plasma renin concentration (PRC). This was repeated after 60 min in SP, immediately after turning the patient into PP, and 60 min thereafter. Net arterial/mixed venous ET-1 clearances and net Ang II formations were calculated.. arterial oxygen tension increased from SP to PP by an average of 60 mmHg, about 20%. Arterial ET-1 concentrations of ARDS patients were 1.57 +/- 1.1 pg/ml (mean +/- SD) and within the range of healthy persons. Net ET-1 clearances were negative in SP, indicating pulmonary release of ET-1, and did not change in PP. Arterial Ang II concentrations (73 +/- 56 pg/ml) as well as PRC (126 +/- 85 pg/ml) were markedly elevated. Net transpulmonary Ang II formation did not change.. Acute changes of oxygenation in ARDS patients by positioning do not induce any short-term effects on pulmonary ET-1 net clearance or Ang II net formation.

Topics: Adult; Analysis of Variance; Angiotensin II; Critical Illness; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Hemodynamics; Humans; Male; Middle Aged; Prone Position; Renin; Respiratory Distress Syndrome; Severity of Illness Index; Supine Position

Antithrombin (AT) III reduces lung damage in animal models of septic acute respiratory distress syndrome (ARDS), which is generally attributed to stimulation of endothelial prostacyclin synthesis. However, clinical studies have failed so far to demonstrate mortality reduction by application of AT III. We investigated whether AT III stimulates pulmonary prostacyclin release. In addition, we hypothesized that it may promote pulmonary endothelins, thereby mitigating its own protective effect in the course of ARDS.. Controlled experiment using isolated organs.. Experimental laboratory.. Male Wistar rats.. Isolated lungs were perfused over 120 mins in recirculatory mode in the presence of 50 microg/mL endotoxin (n = 11), 2U/mL AT III (n = 10), 5 U/mL AT III (n = 13), endotoxin plus 2 U/mL AT III (n = 5), or vehicle alone (controls, n = 13), respectively.. We determined the effects of AT III on vascular release of thromboxane B2, 6-keto-prostaglandin-F1alpha, big endothelin-1, and endothelin-1. Control lungs released 59+/-23 pg/mL thromboxane B2, 1,480+/-364 pg/mL 6-keto-prostaglandin-F1alpha, 15.2+/-4.5 pg/mL big endothelin-1, and 0.46+/-0.13 pg/mL endothelin-1. Exposure to endotoxin increased thromboxane B2 release 2.9-fold, 6-keto-prostaglandin-F1alpha release 1.6-fold, and endothelin-1 1.6-fold (p < .05 each); levels of big endothelin-1 were unchanged. AT III at 2 U/mL elevated production of big endothelin-1 (1.7-fold) and endothelin-1 (1.2-fold) (p < .05 for both). AT III at 5 U/mL enhanced levels of big endothelin-1 (1.6-fold) and endothelin-1 (1.3-fold) (p < .05 for both). Neither dose of AT III affected thromboxane B2 or 6-keto-prostaglandin-F1alpha concentrations. Application of 2 U/mL AT III plus endotoxin stimulated big endothelin-1 production (2.6-fold) compared with endotoxin or AT III alone (p < .05 for both), but did not further elevate endothelin-1 release.. AT III does not stimulate pulmonary prostacyclin, but promotes pulmonary release of big endothelin-1 and endothelin-1 under basal and, particularly, under septic conditions, which may blunt the AT III-induced lung protection during ARDS. Therefore, we suggest combined application of AT III and endothelin antagonists in animal models of septic ARDS.

Topics: Analysis of Variance; Animals; Antithrombin III; Endothelin-1; Endotoxins; Epoprostenol; Humans; Infant, Newborn; Male; Rats; Rats, Wistar; Respiratory Distress Syndrome; Sepsis; Serine Proteinase Inhibitors; Thromboxane B2

1. The effect of the novel ET(A) receptor antagonist LBL 031 and other selective and mixed endothelin receptor antagonists on endothelin-1 (ET-1)-induced and lipopolysaccharide (LPS)-induced microvascular leakage was assessed in rat airways. 2. Intravenously administered ET-1 (1 nmole kg(-1)) or LPS (30 mg kg(-1)) caused a significant increase in microvascular leakage in rat airways when compared to vehicle treated animals. 3. Pre-treatment with the selective ET(A) receptor antagonists, LBL 031 or PD 156707, or the mixed ET(A/B) receptor antagonist, bosentan (each at 30 mg kg(-1)), reduced ET-1-induced leakage to baseline levels. ET-1-induced leakage was not reduced by pre-treatment with the ET(B) selective antagonist BQ 788 (3 mg kg(-1)). 4. Pre-treatment with the selective ET(A) receptor antagonist, LBL 031 (0.1 mg kg(-1)) or PD 156707 (10 mg kg(-1)), or the mixed ET(A/B) receptor antagonist, bosentan (30 mg kg(-1)), reduced LPS-induced leakage by 54, 48 and 59% respectively. LPS-induced leakage was not affected by pre-treatment with the ET(B) selective antagonist BQ 788 (3 mg kg(-1)). 5. The data suggests that ET-1-induced microvascular leakage in the rat airway is ET(A) receptor mediated and that part of the increase induced by LPS may be due to the actions of ET-1. Therefore, a potent ET(A) receptor selective antagonist, such as LBL 031, may provide a suitable treatment for inflammatory diseases of the airways, especially those involving LPS and having an exudative phase, such as the septic shock-induced adult respiratory distress syndrome.

Topics: Animals; Antihypertensive Agents; Bosentan; Capillary Permeability; Endothelin Receptor Antagonists; Endothelin-1; Humans; Infant, Newborn; Lipopolysaccharides; Male; Oligopeptides; Piperidines; Rats; Rats, Wistar; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Respiratory Distress Syndrome; Sulfonamides

Topics: Endothelin-1; Humans; Lung; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Respiratory Distress Syndrome

In the process of developing a model of Escherichia coli endotoxin-induced acute lung injury and shock in specific pathogen-free pigs, the effects of pretreatment with metyrapone (a cortisol-synthesis inhibitor) were examined. Metyrapone was administered 1.5 h before start of endotoxin infusion at t = 0 h (MET-ETOX group, n = 6). At the end of the experiments (t = 4 h) a bronchoalveolar lavage (BAL) was performed. Control animals received only endotoxin (CON-ETOX group, n = 6) or metyrapone (MET-CON group, n = 4). The following results are presented as means +/- SEM. It was found that metyrapone successfully blocked endogenous cortisol synthesis (plasma cortisol levels were 41.0 +/- 5.9 nM in MET-ETOX vs. 339.0 +/- 37.7 nM in CON-ETOX at t = 4 h, P <0.01). At t = 4 h the MET-ETOX animals had substantially increased systemic hypotension compared to the CON-ETOX group (mean arterial pressure 26.7 +/- 4.3 vs. 77.7 +/- 12.2 mmHg, P <0.01), decreased dynamic lung compliance (10.9 +/- 0.7 vs. 13.7 +/- 0.6 ml/cmH2O, P <0.01), increased percentage of BAL neutrophils (28.4 +/- 6.5 vs. 6.6 +/-1.8, P <0.01), pulmonary edema (BAL total protein 0.82 +/- 0.21 vs. 0.42 +/- 0.09 mg/mL, P <0.05), elevated levels of interleukin-8 (1924 +/- 275 vs. 324 +/- 131 pg/mL, P <0.01) and acidosis (pH 7.11 +/- 0.03 vs. 7.23 +/- 0.06, P <0.05). The MET-ETOX group also showed an increased pulmonary hypertension between 2 and 3 h after start of endotoxin infusion and a trend toward significantly increased levels of plasma interleukin-8 (P = 0.052). Arterial pCO2, pO2/FiO2, plasma endothelin-1, plasma TNFalpha, and blood leukocytes were not markedly influenced by the plasma cortisol levels. Nitric oxide production did not seem to be altered by endotoxin infusion in this model, in contrast to other animal studies; this discrepancy could be thought to be due to endotoxin-dosage differences or species differences. It is concluded that if endogenous cortisol production is blocked by metyrapone, the reactions occurring as a result of the endotoxin-induced acute lung injury and shock are greatly enhanced and that therefore pretreatment with metyrapone might be an important addition to this model with specific pathogen-free pigs.

Topics: Acid-Base Imbalance; Animals; Blood Gas Analysis; Bronchoalveolar Lavage Fluid; Disease Models, Animal; Endothelin-1; Endotoxins; Female; Hydrocortisone; Hypotension; Interleukin-8; Leukocytes; Male; Metyrapone; Neutrophils; Nitric Oxide; Nitrites; Peroxidase; Proteins; Pulmonary Edema; Respiratory Distress Syndrome; Respiratory Function Tests; Shock; Specific Pathogen-Free Organisms; Swine; Tumor Necrosis Factor-alpha

To explore the changes of the markers of pulmonary vascular endothelial cell (PVEC) in patients with ARDS.. The levels of plasma circulating endothelial cell(CEC), granule membrane protein-140(GMP-140), endothelin-1(ET-1) and von Willebrand factor (vWF) were determined respectively in 13cases of ARDS. The vWF on the surface of the PVEC were stained in 5 cases of ARDS.. Circulating CEC, GMP-140, ET-1 and vWF levels were increased significantly (P < 0.01) but scores of vWF expression on the PVEC became weak (P < 0.01) in ARDS samples. The level of plasma GMP-140 elevated dramatically in 2nd day( > 4 times).. PVEC are severely impaired during ARDS. GMP-140 released from PVEC might be a satisfactory criteria for early surveillance and for evaluation of prognosis of ARDS in clinical practice.

Topics: Adult; Aged; Biomarkers; Endothelin-1; Endothelium, Vascular; Female; Humans; Male; Middle Aged; P-Selectin; Respiratory Distress Syndrome; von Willebrand Factor

To examine the pathophysiologic role of vasoactive eicosanoids and endothelin-1 in granulocyte-mediated effects in the pulmonary vasculature.. Prospective experimental study in rabbits.. Experimental laboratory in a university teaching hospital.. Thirty adult rabbits.. The experiments were performed on 30 isolated and ventilated rabbit lungs that were perfused with a cell- and plasma-free buffer solution.. The pulmonary arterial pressure and the lung weight gain were continuously registered. Intermittently perfused samples were taken to determine endothelin-1 and thromboxane A2 concentrations. Six experiments without intervention served as the sham group. The granulocytes in the pulmonary circulation were stimulated with N-formyl-L-leucin-methionyl-L-phenylalanine (FMLP; 10(-6) M; control, n = 6). To investigate whether activated granulocytes influence the pulmonary vasculature via endothelin-1, the endothelin-A receptor antagonist LU135252 (10(-6) M) was added to the perfusate before FMLP injection (n = 6). The potential involvement of thromboxane A2 in granulocyte-endothelial interaction was investigated by pretreatment with the cyclooxygenase inhibitor diclofenac (10 microg/mL; n = 6). Activation of granulocytes resulted in an acute increase in pulmonary arterial pressure (>9 mm Hg), which was followed by a second delayed pressure increase after 60 mins (>14 mm Hg) and was paralleled by a massive generation of thromboxane A2 (>250 pg/ mL). Fifteen minutes after FMLP-injection, endothelin-1 was detectable in the perfusate. Pretreatment with the selective endothelin-A antagonist LU135252 significantly (p< .01) reduced the initial pressure response after FMLP stimulation, while diclofenac significantly reduced (p < .05) the delayed pressure increase. Using diclofenac (10 microg/mL) in conjunction with LU135252 (10(-6) M; n = 6) before FMLP injection significantly reduced the early and the delayed pressure increase.. Activated granulocytes seem to enhance pulmonary vascular resistance via endothelin-1 and thromboxane A2. The endothelin-1 effects are probably mediated via endothelin-A receptors since the endothelin-A receptor antagonist LU135252 was able to suppress the early pressure reaction after FMLP injection, whereas the cyclooxygenase inhibitor diclofenac was able to reduce the second pressure increase.

Topics: 6-Ketoprostaglandin F1 alpha; Analysis of Variance; Animals; Cyclooxygenase Inhibitors; Diclofenac; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Female; Granulocytes; In Vitro Techniques; Male; N-Formylmethionine Leucyl-Phenylalanine; Perfusion; Phenylpropionates; Prospective Studies; Pulmonary Artery; Pyrimidines; Rabbits; Random Allocation; Respiratory Distress Syndrome; Thromboxane A2; Thromboxane B2; Vascular Resistance

To examine the effect of a single episode of continuous venovenous haemofiltration (CVVH) on indicators of endothelial injury and the protein C/S system in critically ill patients.. Observational study.. University teaching hospital intensive care unit.. 12 critically ill patients with acute renal failure receiving their first episode of CVVH.. Blood samples were collected prior to starting CVVH and at 15 min and 1, 3-4, 8-12, and 24 h, and at 24-h intervals thereafter until the filter clotted.. Soluble tissue factor, soluble thrombomodulin, E-selectin and endothelin-1 were measured as indicators of endothelial injury. Changes in the protein C/S system were assessed by measurement of protein C (PC) and both free and total protein S (PS). Levels of PC and both free and total PS were subnormal in 6 and 11 patients, respectively, prior to CVVH, but there were no further changes during CVVH. Levels of tissue factor, thrombomodulin, E-selectin, and endothelin-1 were raised prior to haemofiltration in 9, 10, 9 and 9 patients, respectively. There were further increases during CVVH in at least one, but not all, of the markers of endothelial injury in most patients. There was no consistency between the changes in different markers of endothelial injury during haemofiltration in individual patients.. The PC/PS system and endothelial integrity is compromised in critically ill patients prior to haemofiltration, but a single episode of CVVH has little effect on the PC/PS system. The increase in markers of endothelial dysfunction seen during CVVH is more likely to be related to the underlying condition of the patient rather than any specific consequence arising from the technique itself.

Topics: Acute Kidney Injury; Adult; Aged; Blood Coagulation Factors; Critical Illness; E-Selectin; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Hemofiltration; Humans; Intensive Care Units; Male; Middle Aged; Respiratory Distress Syndrome; Treatment Outcome

On the rat acute lung injury model produced by intraperitoneal cavity injection of zymosan showed that the respiratory rate became slow at first time (1st day), subsequently became rapid. Pulmonary histology showed that there was an accumulation of neutrophils in pulmonary microvessels, neutrophils infiltration in interstitial tissue, interetital and olveolar edema, hyaline membrane, atelectasis. Positive expression of ET-1 in experimental rats was stronger than than contral rats. Image analysis showed that OD value was elevated, especially at the fist day. The quantity of ET-1 was corresponding to the degree of pathologic change of acute lung injury. It suggests that the ET-1 might play an important role in the mechanism of acute lung injury.

Topics: Animals; Endothelin-1; Lung; Male; Rats; Rats, Wistar; Respiratory Distress Syndrome; Zymosan

Septic shock is characterised by a decrease in systemic vascular resistance. Nevertheless, regional increases in vascular resistance can occur which may predispose to organ dysfunction, including the adult respiratory distress syndrome (ARDS). Because endothelial damage is a major feature of acute lung injury, we examined whether the potent endothelial vasoconstrictor peptide endothelin-1 plays a pathophysiological role in sepsis or ARDS.. Plasma endothelin was measured in mixed venous, pulmonary capillary and arterial blood, and the relationship with outcome measures was determined.. The intensive care unit of a university teaching hospital.. A consecutive series of well-characterised patients with sepsis syndrome, both with (n = 11) and without (n = 15) ARDS, and ventilated controls without sepsis or ARDS (n = 7).. Plasma endothelin was significantly elevated in patients with sepsis alone and in patients with sepsis and ARDS. Plasma endothelin did not differ among mixed venous, pulmonary capillary and systemic arterial blood. On multiple regression analysis, plasma endothelin correlated positively with organ failure score and with oxygen consumption, and negatively with the PaO2 : FiO2 ratio. There was no correlation with plasma creatinine, suggesting that decreased renal clearance did not account for the high plasma endothelin concentrations.. Although the lung does not appear to be the major site of endothelin production in critically ill patients with sepsis, increased endothelin production may contribute to regional increases in vascular [correction of vacular] resistance, hyperfusion, and the development of organ failure, including ARDS, in patients with sepsis.

Topics: Case-Control Studies; Endothelin-1; Endothelium, Vascular; Humans; Lung; Multiple Organ Failure; Oxygen Consumption; Pulmonary Circulation; Pulmonary Gas Exchange; Regression Analysis; Respiratory Distress Syndrome; Severity of Illness Index; Systemic Inflammatory Response Syndrome; Vascular Resistance