endothelin-1 and Sepsis

Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor, mainly secreted by endothelial cells. It acts through two types of receptors: ETA and ETB. Apart from a vasoconstrictive action, ET-1 causes fibrosis of the vascular cells and stimulates production of reactive oxygen species. It is claimed that ET-1 induces proinflammatory mechanisms, increasing superoxide anion production and cytokine secretion. A recent study has shown that ET-1 is involved in the activation of transcription factors such as NF-κB and expression of proinflammatory cytokines including TNF-α, IL-1, and IL-6. It has been also indicated that during endotoxaemia, the plasma level of ET-1 is increased in various animal species. Some authors indicate a clear correlation between endothelin plasma level and morbidity/mortality rate in septic patients. These pathological effects of ET-1 may be abrogated at least partly by endothelin receptor blockade. ET-1 receptor antagonists may be useful for prevention of various vascular diseases. This review summarises the current knowledge regarding endothelin receptor antagonists and the role of ET-1 in sepsis and inflammation.

Topics: Animals; Bosentan; Cytokines; Endothelin Receptor Antagonists; Endothelin-1; Humans; Inflammation; Lipopolysaccharides; NF-kappa B; Oligopeptides; Peptides, Cyclic; Piperidines; Pyridines; Reactive Oxygen Species; Sepsis; Signal Transduction; Sulfonamides; Superoxides; Tetrazoles

The endothelial integrity, as mechanical barrier against microorganisms and as natural "anticoagulant", is crucial for physiologic organ function. Systemic activation of the endothelium upon inflammation, sepsis, and septic shock is always ending in blood-tissue barrier disruption. With increasing dysfunction, uncontrolled clotting activation, capillary microthrombi formation, tissue edema, local hypoxia, and ischemia are initiated. This in turn enhances a vicious circle leading to multiple organ failure and death. Therefore, biomarkers reflecting this special compartment may help in the early detection of systemic inflammation and its complications. This review provides an overview of the most important endothelial biomarkers and their possible use in sepsis.

Topics: ADAM Proteins; ADAMTS13 Protein; Angiopoietin-1; Angiopoietin-2; Biomarkers; Child; Endothelin-1; Endothelium, Vascular; Fibrin Fibrinogen Degradation Products; Humans; Infant, Newborn; Inflammation; Multiple Organ Failure; Neoplasm Proteins; Plasminogen Activator Inhibitor 1; Platelet-Derived Growth Factor; Proteoglycans; Selectins; Sepsis; Shock, Septic; Urokinase-Type Plasminogen Activator; Vascular Endothelial Growth Factor A; von Willebrand Factor

Sepsis causes significant alterations in the hepatic macro- and microcirculation. Diverging views exist on global hepatic blood flow during experimental sepsis because of the large variety in animal and sepsis models. Fluid-resuscitated clinical sepsis is characterized by ongoing liver ischemia due to a defective oxygen extraction despite enhanced perfusion. The effects of vasoactive agents on the hepatosplanchnic circulation are variable, mostly anecdotal, and depend on baseline perfusion, time of drug administration, and use of concomitant medication. Microvascular blood flow disturbances are thought to play a pivotal role in the development of sepsis-induced multiorgan failure. Redistribution of intrahepatic blood flow in concert with a complex interplay between sinusoidal endothelial cells, liver macrophages, and passing leukocytes lead to a decreased perfusion and blood flow velocity in the liver sinusoids. Activation and dysfunction of the endothelial cell barrier with subsequent invasion of neutrophils and formation of microthrombi further enhance liver tissue ischemia and damage. Substances that regulate (micro)vascular tone, such as nitric oxide, endothelin-1, and carbon monoxide, are highly active during sepsis. Possible interactions between these mediators are not well understood, and their therapeutic manipulation produces equivocal or disappointing results. Whether and how standard resuscitation therapy influences the hepatic microvascular response to sepsis is unknown. Indirect evidence supports the concept that improving the microcirculation may prevent or ameliorate sepsis-induced organ failure.

Topics: Animals; Carbon Monoxide; Endothelin-1; Humans; Liver; Liver Circulation; Microcirculation; Multiple Organ Failure; Nitric Oxide; Sepsis; Shock, Septic; Splanchnic Circulation

Despite the fact that septic patients exhibit altered cardiac function, it is not considered a major pathology during sepsis. Thus, the molecular mechanisms underlying sepsis-induced myocardial dysfunction have not been studied extensively. In a polymicrobial septic rat model, +dP/dt and -dP/dt on day 1 were not altered but found depressed later, i.e., at 3 and 7 days postsepsis. Diastolic dysfunction characterized by an elevation of the time constant of left ventricular relaxation, tau, was evident at 1, 3, and 7 days postsepsis. Recent data from our laboratory demonstrated that sepsis-induced cardiodynamic alterations correlated with upregulation of TNF receptor-associated death domain, Bax, Smac (both mitochondrial and cytosolic fractions), total nuclear factor kappaB expression, p38-mitogen-activated protein kinase and c-Jun N-terminal kinase phosphorylation, and cytochrome c levels in the rat heart at 3 and 7 days postsepsis. Data from various laboratories emphasized that molecular myocardial alteration, which occurs during early and late stages of sepsis, needs to be elucidated thoroughly. A poor understanding of myocardial signaling during early sepsis could be one of the main reasons for limited success of pharmacotherapeutic options for sepsis. We anticipate that an increased understanding of pathophysiological mechanisms leading to sepsis-induced myocardial dysfunction would generate new enthusiasm among various research groups in this area of research.

Topics: Animals; Apoptosis; Endothelin-1; Heart; Heart Failure; JNK Mitogen-Activated Protein Kinases; Myocardium; p38 Mitogen-Activated Protein Kinases; Rats; Sepsis; Signal Transduction

Heart disease is among the leading causes of death in all populations. Cardiac dysfunctions are major complications in patients with advanced viral or bacterial infection, severe trauma and burns accompanied with multiple organ failure - collectively known as systemic inflammatory response syndrome (SIRS). SIRS, which is often subsequent to sepsis, is clinically featured by hypotension, tachypnea, hypo- or hyperthermia, leukocytosis and myocardial dysfunction. The striking association between inflammation and cardiac dysfunction not only prognoses likelihood of survival in patients with SIRS but also prompts the necessity of understanding the pathophysiology of cardiac dysfunction in SIRS, so that effective therapeutic regimen may be identified. Compelling evidence has shown significant and independent link among inflammation, sepsis, insulin resistance and cardiac dysfunction. Several cytokine signaling molecules have been speculated to play important roles in the onset of cardiac dysfunction under SIRS including endothelin-1 and toll-like receptor. Involvement of these pathways in cardiac dysfunction has been convincingly validated with transgenic studies. Nevertheless, the precise mechanism of action underscoring inflammation-induced cardiac contractile dysfunction is far from being clear. Given the substantial impact of inflammation and SIRS on health care, ecosystems and national economy, it is imperative to understand the cellular mechanisms responsible for cardiac contractile dysfunction under inflammation and sepsis so that new and effective therapeutic strategy against such devastating heart problems may be developed.

Topics: Animals; Biopterins; Cytokines; Diabetes Mellitus; Endothelin-1; Heart Diseases; Humans; Inflammation; Insulin Resistance; Myocardium; Nitric Oxide; Sepsis; Shock, Septic; Systemic Inflammatory Response Syndrome; Toll-Like Receptors

Topics: Acute Kidney Injury; Adenosine; Endothelin-1; Humans; Interleukins; Leukotrienes; Nitric Oxide; Platelet Activating Factor; Renal Circulation; Sepsis; Tumor Necrosis Factor-alpha

Among septic patients admitted to the intensive care unit (ICU), early recognition of those with the highest risk of death is of paramount importance. We evaluated the prognostic value of Procalcitonin (PCT), mid regional-proadrenomedullin (MR-proADM), copeptine and CT-proendothelin 1 (CT-ProET 1) concentrations.. This was a prospective cohort study, which included 173 septic patient admitted to one ICU. Blood samples for biomarker measurements were obtained upon admission and on day 5. The predictive value of each biomarker regarding the risk of death at day 28 was assessed. The fluid balance was evaluated from admission to day 5.. All cause ICU mortality was 36.4%. All the biomarkers except CT-ProET-1 were significantly more elevated in the non-survivors than in the survivors upon day 1. This was especially true for MR-proADM (8.6 [5.9] vs. 4.4 [3.9] nmol/L; P < 0.0001) and for the CT-proET-1/MR-proADM ratio (52.9 [22.4] vs. 31.3 [26.6] arbitrary units; P < 0.0001). The best AUROCC values on day 1 were obtained with MR-ProADM and the CT-proET-1/MR-proADM ratio as well (0.75 [0.67-0.85] and 0.82 [0.75-0.89]; 95% CI, respectively). An improved accuracy was achieved on day 5. Moreover, MR-ProADM baseline levels and fluid balance over the 5-day period following ICU admission were strongly correlated (Rho = 0.41; P < 0.001).. In patients admitted to the ICU with sepsis, MR-ProADM on admission was the best predictor of short-term clinical outcome if compared with others. This could be related to its ability to predict fluid sequestration.

Topics: Adrenomedullin; Aged; Aged, 80 and over; Biomarkers; Calcitonin; Disease-Free Survival; Endothelin-1; Female; Glycopeptides; Hospital Mortality; Hospitalization; Humans; Intensive Care Units; Male; Middle Aged; Protein Precursors; Sepsis; Time Factors

To determine the time course of big-endothelin (big-ET) and its relationship to proinflammatory cytokines and organ function in sepsis.. Prospective analysis in patients meeting criteria of severe sepsis as part of a multicenter study (RAMSES) with an anti-tumor necrosis factor monoclonal antibody F(ab')2 fragment (afelimomab).. University hospital intensive care unit.. A total of 23 nontrauma patients with severe sepsis or septic shock and ten multiple trauma patients. Septic patients were randomized for additional experimental treatment when initial interleukin (IL)-6 serum level was above 1000 pg/mL.. Randomized patients received 1.0 mg/kg afelimomab or placebo three times daily over 3 days in addition to standard treatment. In each patient, serial blood samples for plasma big-ET and cytokine determination as well as clinical data were collected over 28 days.. Significantly increased concentrations of circulating big-ET were found in patients with severe sepsis as compared with healthy subjects. In septic patients, big-ET plasma levels were higher than in multiple trauma patients, and were more elevated in randomized than in nonrandomized patients. At study entry (day 0), big-ET reached a peak concentration and significantly correlated with IL-6 (r2 = .43) and IL-8 (r2 = .44) in patients with severe sepsis. Moreover, big-ET levels in septic patients, pooled over all observation days, correlated positively with pressure-adjusted heart rate, central venous pressure, pulmonary artery pressure, and pulmonary vascular resistance and correlated inversely with creatinine clearance (r2 = .54, .54, .59, .40, and .51, respectively, p = .0001). In all randomized septic patients, pressure-adjusted heart rate decreased from day 0 to day 2 in parallel with big-ET; however, a significant decrease in big-ET (day 0 to day 2) was only found in patients additionally treated with afelimomab.. In patients with severe sepsis, big-ET plasma levels are markedly increased, even above those of multiple trauma patients, in close relationship to IL-6 and IL-8, and with significant correlation to renal function and pulmonary vascular tone.

Topics: Adult; Cardiovascular System; Endothelin-1; Endothelins; Female; Humans; Kidney; Male; Middle Aged; Prospective Studies; Protein Precursors; Sepsis; Tumor Necrosis Factor-alpha

To assess the effects of the angiotensin-converting enzyme inhibitor enalaprilat on endothelial cells in septic patients.. Prospective, randomized, placebo-controlled, blinded study.. Clinical investigation on a surgical intensive care unit of a university hospital.. Forty surgical septic patients (noncardiac/nonneurosurgical patients).. After inclusion in the study and after baseline data were obtained, either 0.25 mg/hr (enalaprilat group, n = 20) or saline solution as placebo (control group, n = 20) was continuously given and continued throughout the following 5 days.. Extensive hemodynamic monitoring was carried out in all patients. Plasma concentrations of endothelin-1, angiotensin II, soluble thrombomodulin, and soluble adhesion molecules (endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and granule membrane protein-140) were measured from arterial blood samples. All measurements were carried out before the start of the infusion ("baseline" values) and daily during the following 5 days. All endothelial-derived substances (thrombomodulin, endothelin-1, and all soluble adhesion molecules) were similarly increased beyond normal in both group. Endothelin-1 increased only in the untreated control patients (from 6.9 +/- 0.7 to 14.3 +/- 1.4 mg/mL). Soluble thrombomodulin increased in the untreated control patients (from 58 +/- 9 to 79 +/- 14 ng/mL [p < .05]), but significantly decreased in the enalaprilat-treated patients. Soluble adhesion molecules increased in the untreated control group (endothelial leukocyte adhesion molecule from 92 +/- 14 to 192 +/- 29 ng/mL; intercellular adhesion molecule-1 from 480 +/- 110 to 850 +/- 119 ng/ mL) and returned almost to normal values in the enalaprilat patients. The survival rate did not differ significantly between the two groups. Control patients developed severe sepsis and septic shock more often than the enalaprilat-treated group.. The complex pathogenesis of endothelial function abnormalities in sepsis may offer a large number of pharmacologic interventions. Administration of the angiotensin-converting enzyme inhibitor enalaprilat resulted in a reduced release of soluble endothelial-derived substances into the circulating blood, which may indicate an improved endothelial function. The specific actions of enalaprilat on the endothelium have to be elucidated in further studies.

Topics: Aged; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Cell Adhesion Molecules; Critical Illness; Double-Blind Method; Enalaprilat; Endothelin-1; Endothelium, Vascular; Female; Hemodynamics; Humans; Inflammation; Male; Middle Aged; Prospective Studies; Sepsis; Survival Analysis; Thrombomodulin

Sepsis is a serious systemic inflammatory response to infections. In this study, effects of thymol treatments on sepsis response were investigated. A total of 24 rats were randomly divided into 3 different treatment groups, namely as Control, Sepsis and Thymol. A sepsis model was created with a cecal ligation and perforation (CLP) in the sepsis group. For the treatment group, 100 mg/kg dose of thymol was administered via oral gavage and sepsis was established with a CLP after 1 h. All rats were sacrificed at 12 h post-opia. Blood and tissue samples were taken. ALT, AST, urea, creatinine and LDH were evaluated to assess the sepsis response in separated sera. Gene expression analysis was conducted for ET-1, TNF-α, IL-1 in lung, kidney and liver tissue samples. ET-1 and thymol interactions were determined by molecular docking studies. The ET-1, SOD, GSH-Px and MDA levels were determined by ELISA method. Genetic, biochemical and histopathological results were evaluated statistically. The pro-inflammatory cytokines and ET-1 gene expression revealed a significant decrease in the treatment groups, while there was an increase in septic groups. SOD, GSH-Px and MDA levels of rat tissues were significantly different in the thymol groups as compared to the sepsis groups (p < 0.05). Likewise, ET-1 levels were significantly reduced in the thymol groups. In terms of serum parameters, present findings were consistent with the literature. It was concluded based on present findings that thymol therapy may reduce sepsis-related morbidity, which would be beneficial in the early phase of the sepsis.

Topics: Animals; Disease Models, Animal; Endothelin-1; Gene Expression; Molecular Docking Simulation; Rats; Sepsis; Superoxide Dismutase; Thymol; Tumor Necrosis Factor-alpha

Relative bradycardia is the term used to describe the mechanism where there is dissociation between pulse and temperature. This finding is important to recognize since it may provide further insights into the potential underlying causes of disease. There is no known proposed mechanism to explain this phenomenon. We hypothesize that relative bradycardia is the central mechanism reflecting and influenced potentially by the direct pathogenic effect on the sinoatrial node as well as cross-talk between the autonomic nervous system and immune system. Cardiac pacemaker cells may act as a target for inflammatory cytokines leading to alteration in heart rate dynamics or their responsiveness to neurotransmitters during systemic inflammation. These factors account for the important role of how the host response to infectious and non-infectious causes influences the appearance of relative bradycardia. We propose several methods that may be useful to confirm the proposed theoretical framework to further enhance our understanding of this paradoxical phenomenon. This includes measuring, during the episode of relative bradycardia, proinflammatory and anti-inflammatory cytokines, monitoring heart rate variability (HRV), and assessing underlying comorbidities and outcomes in patients with the same disease.

Topics: Autonomic Nervous System; Bradycardia; Comorbidity; Cytokines; Endothelin-1; Heart Rate; Humans; Immune System; Inflammation; Interleukin-6; Lipopolysaccharides; Models, Theoretical; NADPH Oxidases; Neurotransmitter Agents; Nitric Oxide; Pulse; Sepsis; Sinoatrial Node; Temperature; Treatment Outcome; Tumor Necrosis Factor-alpha

Among the dysfunctions and pathologies associated with sepsis, the underlying molecular mechanisms of sepsis-induced acute lung injury (ALI) are poorly understood. Endothelin (ET)-1, a potent vasoconstrictor and pro-inflammatory peptide, is known to be involved in the pathogenesis of ALI in a rat model of sepsis. Here, we investigated whether landiolol hydrochloride, an ultra-short-acting β-blocker, plays a crucial role in ameliorating and attenuating LPS-induced ALI through modulation of the ET-1 system. Male Wistar rats at 8weeks of age were administered with either saline or lipopolysaccharide (LPS) for three hours (3h) and some of the LPS-administered rats were continuously treated with landiolol for 3h. ALI was induced by LPS, including levels of both circulatory and pulmonary TNF-α and IL-6 but [PaO

Topics: Acute Lung Injury; Adrenergic beta-Antagonists; Animals; Down-Regulation; Endothelin-1; Lung; Male; Morpholines; Rats, Wistar; RNA, Messenger; Sepsis; Tumor Necrosis Factor-alpha; Urea

The aim of this study was to determine the actions of caffeic acid phenethyl ester (CAPE) on the changes of endothelin-1 (ET-1) level, tumor necrosis factor- (TNF-) alpha, and oxidative stress parameters such as superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels in experimental sepsis model in rats.. Twenty-four rats were randomly divided into three experimental groups: sham (group 1), sepsis (group 2), and sepsis + CAPE (group 3), n = 8 each. CAPE was administered (10 µmol/kg) intraperitoneally to group 3 before sepsis induction. Serum ET-1, serum TNF-alpha, tissue SOD activity, and tissue MDA levels were measured in all groups.. Pretreatment with CAPE decreased ET-1, TNF-alpha, and MDA levels in sepsis induced rats. Additionally SOD activities were higher in rats pretreated with CAPE after sepsis induction.. Our results demonstrate that CAPE may have a beneficial effect on ET and TNF-alpha levels and oxidative stress parameters induced by sepsis in experimental rat models. Therefore treatment with CAPE can be used to avoid devastating effects of sepsis.

Topics: Animals; Caffeic Acids; Disease Models, Animal; Endothelin-1; Inflammation; Male; Malondialdehyde; Oxidative Stress; Oxygen; Phenylethyl Alcohol; Random Allocation; Rats; Rats, Wistar; Sepsis; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances; Tumor Necrosis Factor-alpha

In the critical care setting, increasing levels of midregional proadrenomedullin (MRproADM), midregional proatrial natriuretic peptide (MRproANP), procalcitonin (PCT), copeptin, and proendothelin-1 (proET-1) have been shown to be correlated with increasing severity of sepsis. The objective of this study was to investigate the utility of sepsis biomarkers in an Emergency Department (ED) population.. Through a prospective, observational pilot study, we investigated the utility of MRproADM, MRproANP, PCT, copeptin, and proET-1 in predicting a diagnosis of early sepsis in patients presenting to the ED for suspected infection. Data were analyzed using nonparametric Mann-Whitney U-tests, χ²-tests, and receiver operating characteristic curves.. Of the 66 patients enrolled in this study, 37 (56.1%) were men, with a median age of 58 years [interquartile range (IQR) 39-69 years], and 19 (28.8%) had a final diagnosis of early sepsis. A higher percentage of sepsis patients compared with no-sepsis patients met systemic inflammatory response syndrome (SIRS) criteria at initial presentation (85.7 vs. 41.3%; P<0.0001) and were admitted to the hospital (84.2 vs. 55.6%; P=0.02). PCT was higher in sepsis patients [median 0.32 ng/ml (IQR 0.19-1.17) vs. 0.18 ng/ml (IQR 0.07-0.54); P=0.04]. There were no differences between groups for MRproADM, MRproANP, copeptin, or proET-1 (P≥0.53). The C-statistic was maximized with the combination of SIRS criteria and PCT levels (0.92±0.05), which was better than PCT alone (0.67±0.08; P=0.005) or SIRS alone (0.75±0.07; P=0.04).. In this pilot study, we found that the combination of SIRS criteria and PCT levels is useful for the early detection of sepsis in ED patients with suspected infection. Larger studies investigating use of PCT are necessary.

Topics: Adrenomedullin; Adult; Aged; Atrial Natriuretic Factor; Biomarkers; Calcitonin; Calcitonin Gene-Related Peptide; Emergency Service, Hospital; Endothelin-1; Female; Glycopeptides; Humans; Male; Middle Aged; Pilot Projects; Prospective Studies; Protein Precursors; Sepsis

Landiolol hydrochloride, an ultra-short-acting highly cardio-selective β-1 blocker, has become useful for various medical problems. Recent studies have demonstrated that co-treatment with landiolol protects against acute lung injury and cardiac dysfunction in rats of lipopolysaccharide (LPS)-induced systemic inflammation, and was also associated with a significant reduction in serum levels of the inflammation mediator HMGB-1 and histological lung damage. Endothelin (ET)-1, a potent vasoconstrictor, has been implicated in pathogenesis of sepsis and sepsis-induced multiple organ dysfunction syndrome. Here, we investigated whether landiolol hydrochloride can play important roles in ameliorating LPS-induced alterations in cardiac ET system of septic rats.. Eight-week-old male Wistar rats were administered LPS only for 3 h and the rest were treated with LPS as well as with landiolol non-stop for 3 h.. At 3 h after LPS (only) administration, circulatory tumor necrosis factor (TNF)-α level, blood lactate concentration and percentage of fractional shortening of heart were significantly increased. In addition, LPS induced a significant expression of various components of cardiac ET-1 system compared to control. Finally, treatment of LPS-administered rats with landiolol for 3 h normalized LPS-induced blood lactate levels and cardiac functional compensatory events, without altering levels of plasma TNF-α and ET-1. Most strikingly, landiolol treatment significantly normalized various components of cardiac ET-1 signaling system in septic rat.. Taken together, these data led us to conclude that landiolol may be cardio-protective in septic rats by normalizing the expression of cardiac vasoactive peptide such as ET, without altering the circulatory levels of inflammatory cytokines.

Topics: Animals; Blood Gas Analysis; Disease Models, Animal; Endothelin-1; Hemodynamics; Interleukin-6; Male; Morpholines; Myocardium; Rats, Wistar; Receptors, Endothelin; Sepsis; Tumor Necrosis Factor-alpha; Ultrasonography; Up-Regulation; Urea

The purpose of this study is to understand the role of rho-kinase (ROCK-2) in the regulation of liver microcirculation after inflammatory stress. Endothelin-1 (ET-1)-induced nitric oxide (NO) is essential in the regulation of blood flow in hepatic sinusoids. Lipopolysaccharide (LPS) inhibits this ET-1-induced NO production and disrupts liver microcirculation; however, the exact molecular mechanism is unknown. Liver sinusoidal endothelial cells were isolated, pretreated with 10 ng/mL LPS for 6 h, and treated with 10 μM Y27632 (ROCK-2 inhibitor) for 30 min and 10 nM ET-1 for 30 min. Lipopolysaccharide induced RhoA membrane translocation that was attenuated by methyl-β-cyclodextrin (cholesterol sequester) or targeted mutation of caveolin-1. Lipopolysaccharide increased ROCK-2 expressions (+60%) and ROCK-2 activity (+36%). Endothelin-1 increased endothelial NO synthase (eNOS) activity (+70%), but LPS inhibited this ET-1-mediated eNOS response. Treatment with Y27632 restored ET-1-mediated eNOS activity (+61%) and stimulated NO production in the perinuclear region after LPS pretreatment. This treatment reduced cofilin-Ser3 phosphorylation (-73%), increased vasodilator-stimulated phosphoprotein-Ser239 phosphorylation (+88%), and stimulated globular actin/eNOS association. Lipopolysaccharide induces Rho/ROCKs signaling pathway to disrupt the ET-1-mediated eNOS activation in liver sinusoidal endothelial cells. Rho-kinase ROCK-2 inhibition restores ET-1-mediated NO production after the LPS pretreatment, in part, through an increase in actin depolymerization.

Topics: Actins; Amides; Animals; Caveolin 1; Cells, Cultured; Cofilin 1; Endothelial Cells; Endothelin-1; Enzyme Activation; Inflammation; Lipopolysaccharides; Liver; Male; Microcirculation; Nitric Oxide; Nitric Oxide Synthase Type III; Phosphorylation; Protein Binding; Protein Structure, Tertiary; Pyridines; Rats; Rats, Sprague-Dawley; rho-Associated Kinases; Sepsis; Serine

The aim of this study was to evaluate echocardiography-based indices of myocardial function and markers of vascular inflammation and endothelial dysfunction in the early phases of severe sepsis.. Forty-five adult patients (67% women; age 51 ± 18 years; Acute Physiology and Chronic Health Disease Classification System II score, 23 ± 7) admitted to the intensive care unit up to 24 hours after fulfilling criteria for severe sepsis or septic shock were studied. Clinical, laboratorial (endothelin 1 [ET1], vascular cellular adhesion molecule 1), and echocardiographic data were collected within the first 24 hours and again 72 hours and 7 days after admission.. Intrahospital mortality was 33% (15 deaths). Left ventricular (LV) dysfunction (LV ejection fraction <55%) was identified in 15 (33%) patients, whereas right ventricular (RV) dysfunction (RV tissue Doppler peak systolic velocity [RV-Sm] <12 cm/s) was present in 14 (30%) patients. LogET1 was increased in patients with LV dysfunction (2.3 ± 0.6 vs 1.8 ± 0.4 pg/mL; P = .01) and RV dysfunction (2.5 ± 0.5 vs 1.8 ± 0.4 pg/mL; P < .001) and had negative correlations with LV ejection fraction (r = -0.50; P = .002) and RV-Sm (r = -0.67; P < .001). Left ventricular end-diastolic diameter, RV-Sm, and diastolic dysfunction were able to discriminate survivors from nonsurvivors, and the combination of these parameters identified groups of very low and high risk.. Both LV and RV systolic dysfunctions are prevalent in severe sepsis, being directly associated with markers of endothelial dysfunction. Left ventricular nondilation, RV dysfunction, and diastolic dysfunction seem related to poor prognosis in this scenario.

Topics: Biomarkers; Brazil; Cardiomyopathy, Dilated; Echocardiography; Endothelin-1; Endothelium, Vascular; Female; Humans; Intercellular Adhesion Molecule-1; Male; Middle Aged; Prognosis; Sepsis; Shock, Septic; Survival Rate; Ventricular Dysfunction

Our aim was to develop a large animal model of sepsis induced by fecal peritonitis, which reproduces the characteristic macrohemodynamic, microcirculatory and inflammatory changes seen in human sepsis.. Anesthetized minipigs were subjected to fecal peritonitis (n = 9; 0.5 g/kg i.p. autofeces) or sham-operation (i.p. saline, n = 6). Invasive hemodynamic monitoring was started with regular blood gas analyses between the 15-24 hr of the insult. Sublingual microcirculation was characterized by red blood cell velocity changes (with orthogonal polarization spectral imaging), and the extravascular lung water index (EVLWI) was measured. The plasma levels of big-endothelin (big-ET) and high-mobility group box protein-1 (HMGB1) were determined from venous blood samples.. The mean arterial pressure gradually decreased below 70 mmHg in septic animals, while the heart rate and cardiac output increased constantly. In spite of the hyperdynamic reaction, significant elevation of the EVLWI was observed, while the sublingual microcirculation deteriorated, as compared with the control group. The big-ET and HMGB1 plasma concentrations were significantly elevated between 6-24 hr of peritonitis.. The in vivo data suggest that our fecal peritonitis-induced experimental sepsis model is of clinical relevance, and may play useful roles in the development of novel, sepsis-related therapies.

Topics: Animals; Arterial Pressure; Biomarkers; Blood Flow Velocity; Cardiac Output; Disease Models, Animal; Endothelin-1; Feces; Heart Rate; Hemodynamics; HMGB1 Protein; Inflammation; Microcirculation; Peritonitis; Sepsis; Swine; Swine, Miniature; Time Factors

To establish reference values in cord blood of the following new sepsis markers: pro-adrenomedullin (MR-proADM), pro-endothelin (CT-proET-1), and pro-atrial natriuretic peptide (MR-proANP).. MR-proADM, CT-proET-1, MR-proANP, and procalcitonin (PCT) were measured in cord blood of newborn infants by Time Resolved Amplified Cryptate Emission (TRACE) technology. The inclusion criteria in the control group (n=194) was the absence of any clinical sign or risk factor of sepsis. A group of 73 newborn infants presenting with risk factors of sepsis at delivery was also studied.. The median values (reference interval) of CT-proET-1, MR-pro-ADM, and MR-proANP measured in cord blood plasma were 72 pmol/L (39-115), 0.84 nmol/L (0.5-1.38), and 163 pmol/L (76-389), respectively. The PCT reference interval was not significantly different from that previously described in cord blood serum.. The reference intervals established will serve as a starting point for further clinical investigations aimed to elucidate the potential prognostic/diagnostic value of these markers in neonatal sepsis management.

Topics: Adrenomedullin; Atrial Natriuretic Factor; Biomarkers; Calcitonin; Calcitonin Gene-Related Peptide; Endothelin-1; Female; Fetal Blood; Fetus; Humans; Infant; Infant, Newborn; Photoelectron Spectroscopy; Pregnancy; Pregnancy Complications, Infectious; Prognosis; Protein Precursors; Reference Values; Sepsis

This experimental study was designed to determine effects of Nigella sativa oil (NSO) on endothelin-1 (ET-1) level and oxidative stress parameters, superoxide dismutase (SOD) and malondialdehyde (MDA) in a rat sepsis model. Twenty four adult Wistar albino rats were divided randomly into three groups: sham group (group 1), sepsis group (group 2), sepsis group pretreated with NSO (group 3). Serum ET-1, tissue SOD and tissue MDA levels were measured in all groups. Compared to group 1, ET-1 and MDA levels were higher in group 2. ET-1 and MDA levels in NSO pretreated group 3 were lower with respect to group 2 (p<0.03, and p<0.02, respectively). Additionally, SOD levels in group 3 were found to be higher than group 2 (p<0.02). Based on our results, it can be concluded that NSO may have a positive impact on ET-1 levels and oxidative stress induced by sepsis in experimental rat models.

Topics: Animals; Endothelin-1; Male; Malondialdehyde; Oxidative Stress; Phytotherapy; Plant Oils; Rats; Rats, Wistar; Sepsis; Superoxide Dismutase

Activated protein C (aPC) promotes fibrinolysis while inhibiting coagulation and inflammation. In septic patients, aPC levels are depleted, and aPC treatment has emerged as a therapeutic option. To better understand the mechanism(s) by which aPC improves survival in sepsis, we sought to determine the effect of aPC treatment on hepatic vasoactive gene and protein expression, leading to changes in hepatic vascular responsiveness in a septic animal model. Under anesthesia, rats underwent sham or cecal ligation and puncture followed by aPC treatment (1 mg/kg, twice daily, i.v.). Treatment with aPC significantly decreased hepatic endothelin 1 (ET-1)/ET A receptor mRNA and protein expression. To determine the effect of aPC on hepatic microvasculature, ET-1-induced changes in liver microcirculation were assessed by intravital microscopy. This approach demonstrated aPC significantly improved hepatic perfusion index in the animals that underwent cecal ligation and puncture in the absence of significant changes in portal venous pressure. Furthermore, although aPC did not affect ET-1-dependent sinusoidal vasoconstriction, aPC induced hepatoprotective effects via enhanced red blood cell velocity. Collectively, these data demonstrate aPC ameliorates ET-1-dependent changes in hepatic microcirculation and improves hepatic function in the setting of sepsis.

Topics: Animals; Endothelin-1; Liver; Male; Microcirculation; Protein C; Random Allocation; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Sepsis

Sepsis remains a serious complication after trauma. Although hepatic microvascular dysfunction occurs during trauma and sepsis, the mechanism responsible is unclear. Since Kupffer cells can provide the signals that regulate the hepatic response in inflammation and contribute to multiple organ failure, this study investigated the role of Kupffer cells in the imbalance of the expression of vasoactive and inflammatory mediators during trauma and sepsis.. The Kupffer cells were inactivated by gadolinium chloride (GdCl(3), 7.5 mg/kg body weight, i.v.) 1 and 2 d before surgery. The animals then underwent femur fracture (FFx) followed 48 h later by cecal ligation and puncture (CLP). After 24 h, blood was obtained to determine the alanine aminotransferase (ALT) activity. Liver samples were also taken for RT-PCR analysis of the mRNA for genes of interest.. Serum ALT levels increased in FFx and CLP. This increase was potentiated by FFx + CLP and was attenuated by GdCl(3). The mRNA expression levels in the FFx showed no change in the ET(A), ET(B), iNOS, and HO-1, and showed a slight increase of 2.6-fold, 2.2-fold, and 2.8-fold for ET-1, eNOS, and TNF-alpha, respectively. The ET-1 mRNA expression level increased after CLP and FFx + CLP. The ET(A) mRNA level showed no change, whereas the ET(B) transcripts increased after CLP. This increase was potentiated after FFx + CLP, and was attenuated by GdCl(3). After CLP alone, iNOS, eNOS, and TNF-alpha mRNA expression levels were increased 20.3-fold, 5.8-fold, and 11.9-fold, respectively. This increase was potentiated after FFx + CLP, and was attenuated by GdCl(3). HO-1 mRNA expression significantly increased after FFx + CLP, and this increase was attenuated by GdCl(3).. Mild trauma alone causes little change in the expression of vasoactive mediators while sequential injury potentiates the imbalanced gene expression induced by sepsis. Kupffer cells might be essential for hepatic microvascular dysfunction after sequential stress.

Topics: Alanine Transaminase; Animals; Endothelin-1; Femoral Fractures; Gadolinium; Heme Oxygenase (Decyclizing); Kupffer Cells; Liver Circulation; Male; Nitric Oxide Synthase Type II; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Receptor, Endothelin B; RNA, Messenger; Sepsis; Tumor Necrosis Factor-alpha

Severe sepsis involves a complex response including the activation of lots of cells, inflammatory mediators, and the hemostatic system. Central to this process is an alteration of endothelial cell function. Therefore, we investigated whether an endothelial bioreactor (EBR) would provide a new therapeutic approach to this clinical disorder.. EBR was constructed using a cartridge which contained with nonwoven polytetrafluoroethylene seeded with porcine iliac artery endothelial cell (PIEC). Pigs were intravenously administered with 0.25 mg/kg lipopolysaccharide and immediately placed in an extracorporeal circuit with EBR or sham controls.. Compared with the sham group, EBR therapy resulted in significantly higher mean arterial blood pressure and significantly lower plasma von Willebrand factor, endothelin-1 and scores of lung injury. These alterations were associated with a significant survival advantage in the EBR group.. Timely intervention with EC therapy in a tissue-engineered bioreactor may improve cardiovascular performance and alter the natural history of endotoxemia sepsis.

Topics: Animals; Bioreactors; Blood Pressure; Endothelial Cells; Endothelin-1; Endotoxemia; Lung; Sepsis; Swine; Tissue Engineering; von Willebrand Factor

To investigate the myocardial protective effects of different dosage of ulinastatin (UTI) and the possible mechanism in septic rats.. Forty male Sprague-Dawley (SD) rats were randomly divided into five groups: control group, sham group, model group, UTI in low dose or high dose group. Cecal ligation and puncture (CLP) was adopted to reproduce animal model of sepsis. Left ventricular myocardium was harvested and blood samples were collected at 24 hours after successful establishment of animal model. Serum cardiac troponin I (cTnI), the contents of myocardial tumor necrosis factor-alpha (TNF-alpha) and endothelin-1 (ET-1) were measured, and myocardial pathological changes were observed.. In the model group, the level of serum cTnI, and the expressions of myocardial TNF-alpha and ET-1 were much higher than those in control group [cTnI (microg/L): 7.58+/-0.53 vs. 1.05+/-0.21, TNF-alpha (pg/g): 945.6+/-72.0 vs. 238.2+/-35.2, ET-1 (pg/g): 776.8+/-123.9 vs. 170.1+/-28.3, all P<0.01]. There were no differences in the levels of serum cTnI, myocardial TNF-alpha and ET-1 between low dose UTI group and the model group [cTnI (microg/L): 7.21+/-0.51 vs. 7.58+/-0.53, TNF-alpha (pg/g): 910.5+/-96.6 vs. 945.6+/-72.0, ET-1 (pg/g): 714.0+/-66.7 vs. 776.8+/-123.9, all P>0.05]. However, serum cTnI, myocardial TNF-alpha and ET-1 were lower significantly in high dose UTI group than in model group [cTnI (microg/L): 4.30+/-0.84 vs. 7.58+/-0.53, TNF-alpha (pg/g): 430.5+/-75.6 vs. 945.6+/-72.0, ET-1 (pg/g): 377.1+/-39.0 vs. 776.8+/-123.9, all P<0.01].. High dose (but not low dose) UTI may protect myocardium from the damage resulted from sepsis in a rat model, probably by lowering expressions of TNF-alpha and ET-1.

Topics: Animals; Disease Models, Animal; Endothelin-1; Glycoproteins; Male; Myocardium; Rats; Rats, Sprague-Dawley; Sepsis; Troponin I; Tumor Necrosis Factor-alpha

Topics: Adult; Aged; Aged, 80 and over; Blood Coagulation; Endothelin-1; Female; Humans; Male; Middle Aged; Prognosis; Sepsis

Sepsis causes changes in vascular resistance and hypovolemia. Previous studies have demonstrated that the spleen regulates blood volume via atrial natiuretic peptide (ANP). We hypothesized that LPS alters extrasplenic responses to ANP via endothelial-dependent mechanisms and studied the role of NO and endothelin 1 (ET-1). Isolated extrasplenic arteries and veins (vessels in mesentery adjoining spleen) were obtained from male Wistar rats weighing 200 to 280 g (n = 102) and mounted on a pressure myograph to determine intraluminal diameter for 4 h. Isolated vessels constricted in response to the half-maximum response of ANP (veins, 30% +/- 1.7%; arteries, 34.5 +/- 1.7%; P < 0.05), and this was abolished by the NO donor S-nitroso-N-acetylpenicillamine (SNAP 75 microM). Arteries and veins incubated with LPS (50 microg mL(-1) for 4 h) were unresponsive to ANP, and constriction was not restored by the NOS inhibitor N omega-nitro-L-arginine methyl ester (L-NAME 100 microM). However, venular constriction returned in the presence of the ET-1 antagonist Bosentan, increasing from -1.5 +/- 1.2 (10 min) to -10 +/- 2.5% (4 h) with LPS + Bosentan (3 x 10(-6) M) compared with -2.3 +/- 1.2 and 0% with LPS alone. In conclusion, LPS abolished endothelial-dependent extrasplenic venular constriction to ANP partially due to increased ET-1, whereas NO seemed to modulate vascular responses to ANP.

Topics: Animals; Antihypertensive Agents; Arteries; Atrial Natriuretic Factor; Blood Volume; Bosentan; Endothelin-1; Enzyme Inhibitors; Hypovolemia; Lipopolysaccharides; Male; Mesentery; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Donors; Penicillamine; Rats; Rats, Wistar; Sepsis; Spleen; Sulfonamides; Vascular Resistance; Vasoconstriction; Veins

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

Endothelin-1 (ET-1), a potent vasoconstrictor, is difficult to measure because of its instability and its binding to receptors and plasma proteins. We report a rapid, robust way to indirectly quantify ET-1 release by measuring the C-terminal ET-1 precursor fragment (CT-proET-1) without an extraction step.. In plasma samples from healthy individuals, patients with congestive heart failure (CHF), and patients with sepsis, we measured CT-proET-1 with a sandwich immunoluminometric assay that uses 2 polyclonal antibodies to amino acids 168-212 of pre-proET-1. We also correlated CT-proET-1 concentrations with bigET-1 measurements.. The assay yielded results within 3 h and showed linear dilution with an analytical detection limit of 0.4 pmol/L and an interlaboratory CV <10% for values >10 pmol/L. Ex vivo CT-proET-1 was stable (<10% loss of immunoreactivity) in EDTA-, heparin-, and citrate-plasma for at least 4 h at room temperature, 6 h at 4 degrees C, and in EDTA-plasma for at least 6 months at -20 degrees C. CT-proET-1 values followed a gaussian distribution in healthy individuals (mean, 44.3 pmol/L; range, 10.5-77.4 pmol/L) without significant differences between males and females. The correlation coefficient for CT-proET-1 vs age was 0.25 (P <0.0001). CT-proET1 was significantly (P <0.0001) increased in patients with CHF (median, 104 pmol/L; range, 50.8-315 pmol/L) and patients with sepsis (median, 189 pmol/L; range, 34.6-855 pmol/L). The correlation between CT-proET-1 and bigET-1 for 43 samples was 0.80 (P <0.0001).. CT-proET-1 measurement is a rapid and easy method for indirectly assessing the release of ET-1 in critically ill patients.

Topics: Endothelin-1; Female; Heart Failure; Humans; Immunoassay; Luminescent Measurements; Male; Peptide Fragments; Protein Precursors; Reference Values; Sepsis

We hypothesized that modulation of endothelin-converting enzyme-1 (ECE-1) activity would affect phosphorylation of p38-mitogen activated protein kinase (p38-MAPK) and potentiate apoptosis in adult rat ventricular myocytes (ARVMs) during sepsis. The activity of ECE-1 in ARVMs was altered by increasing the substrate availability for ECE-1 by exogenous administration of bigendothelin-1 (bigET-1, 100 nM) and by inhibiting ECE-1 using FR901533 (10 microM) for 24-h. FR901533 significantly decreased the concentration of ET-1 in both sham and sepsis groups. FR901533 decreased p38-MAPK phosphorylation in sepsis but not in sham group. BigET-1 upregulated p38-MAPK phosphorylation, produced hypertrophy, decreased cell viability and reversed FR901533-induced down-regulation of p38-MAPK phosphorylation in both groups. Although, FR901533 did not affect cell cross-sectional area, it significantly reduced the viability of ARVM in both groups. The peak shortening of sham ARVMs was elevated by bigET-1, FR901533 and pretreatment with FR901533 followed by bigET-1. However, the contractility of septic ARVMs was not altered by either bigET-1 or FR901533 treatments per se. Septic ARVM exhibited significantly increased caspase-3 activity at 12 and 24-h. Pretreatment with FR901533 significantly elevated caspase-3 activity in both sham and sepsis group. The data demonstrated that bigET-1-induced hypertrophy in septic ARVM correlates with an ECE-1 dependent-activation of p38-MAPK. The results suggest that non-responsiveness of ARVM to bigET-1 is due to ECE-1 dependent apoptosis. We concluded that ECE-1 may play a crucial role in ARVM dysfunction via increased caspase-3 activity and p38-MAPK phosphorylation during sepsis.

Topics: Animals; Apoptosis; Aspartic Acid Endopeptidases; Caspase 3; Caspases; Endothelin-1; Endothelin-Converting Enzymes; Heart Ventricles; Male; MAP Kinase Signaling System; Metalloendopeptidases; Myocardial Contraction; Myocytes, Cardiac; p38 Mitogen-Activated Protein Kinases; Rats; Rats, Sprague-Dawley; Sepsis; Tetracyclines

Macrophages undergo maladaptive alterations after trauma. In this study, we assessed the role of Kupffer cells in hepatic microcirculatory response to endothelin-1 (ET-1) after femur fracture (FFx) and cecal ligation and puncture (CLP).. Sprague-Dawley rats (200-300 g) underwent sham, FFx, CLP, or FFx + CLP. To ablate Kupffer cells, group 1 animals were treated with gadolinium chloride, and group 2 animals received saline. Hepatic microcirculation was assessed by intravital microscopy. Liver mitochondrial redox state and tissue oxygen (tPo2) were determined by NADH and ruthenium fluorescence, respectively. Liver damage was estimated by alanine aminotransferase levels. Differences were assessed using analysis of variance followed by Student-Newman-Keuls post hoc test.. After 10 minutes of ET-1, CLP and FFx + CLP caused significant reduction in hepatic perfusion index (2.5-fold and 5-fold vs. sham, p < 0.05, respectively), redox state (36% and 45% vs. sham, p < 0.01, respectively), tPo2 (10% and 12% vs. sham, p < 0.05, respectively), and more liver damage compared with sham and FFx-treated animals. Kupffer cell depletion restored microcirculation, redox state, and tPo2 and abrogated hepatocellular damage.. Kupffer cells contribute directly to hepatic microcirculatory dysfunction and liver injury after inflammatory stress. Furthermore, Kupffer cell depletion ameliorates the microcirculatory perturbations of trauma and sepsis. Thus, modulation of Kupffer cell response may prove beneficial.

Topics: Animals; Cecum; Endothelin-1; Femoral Fractures; Ferrous Compounds; Kupffer Cells; Ligation; Liver; Liver Circulation; Male; Microcirculation; NAD; Rats; Rats, Sprague-Dawley; Sepsis

Earlier we have demonstrated that inhibition of endothelin biosynthesis ameliorates endotoxemia-induced inducible nitric oxide synthase (iNOS) activation and phosphorylation of p38-mitogen activated protein kinase (pp38-MAPK). Therefore, in the present study, we tested the hypothesis that activation of endothelin (ET)-1 biosynthesis using bigET-1 during early sepsis would upregulate iNOS and affect myocardial function in the rat. Male Sprague-Dawley rats (350-400 g) were anesthetised using Nembutal (50 mg/kg, i.p.) and jugular vein, tail artery (Mean arterial pressure, MAP) and right carotid arteries (advanced to left ventricle, LV) were cannulated. The rats were randomly divided into saline-, bigET-1- and C-terminal fragment of bigET-1 (bigET-1(22-38))-treated groups. Sepsis was induced using i.p. injection of cecal inoculum obtained from a donor rat (200 mg/kg in 5 ml 5% sterile dextrose water, D5W). Sham animals received an i.p. injection of D5W (5 ml/kg). MAP and LVP were recorded and cardiodynamic parameters were calculated at 0, 2, 6, 12 and 24 h post sham or sepsis-induction. A significant elevation in LV isovolumic relaxation rate constant (tau), LV end diastolic pressure (LVEDP) and rate pressure product (RPP) was observed in vehicle-treated septic group at 24 h. BigET-1 significantly increased concentration of LV ET-1 both in sham and septic groups. BigET-1 elevated tau and LVEDP both in sham and septic animals as early as 12 h which persisted through 24 h. However, bigET-1(22-38) elevated LVEDP in septic group at 24 h but not in sham group. BigET-1 accentuated the levels of plasma nitric oxide byproduct (NOx) levels in both sham and septic animals at 6, 12 and 24 h. Sepsis increased myocardial iNOS at 24 h. BigET-1 significantly upregulated expression of myocardial iNOS and pp38-MAPK. The data suggest that increased substrate availability for ET-1 at the time of sepsis-induction contributes in diastolic dysfunction, iNOS activation and p38-MAPK phosphorylation.

Topics: Animals; Endothelin-1; Enzyme Activation; Hemodynamics; Male; Mitogen-Activated Protein Kinases; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; p38 Mitogen-Activated Protein Kinases; Peptide Fragments; Phosphorylation; Rats; Rats, Sprague-Dawley; Sepsis; tau Proteins; Ventricular Dysfunction, Left

We tested the hypothesis that exogenous administration of the ET-1 precursor, bigET-1, would regulate adult rat ventricular myocyte (ARVM) contractility in a p38-mitogen activated protein kinase (p38-MAPK)-dependent mechanism during sepsis. Ventricular myocytes from adult rat hearts (both sham and septic) were stimulated to contract at 0.5 Hz and mechanical properties were evaluated using an IonOptix Myocam system. Immunoblot analysis was used to determine the phosphorylation of p38-MAPK and extracellular signal-regulated kinase 1/2 (ERK1/2). ARVMs were treated with vehicle, bigET-1 and inhibitors for 24 h and then subjected to functional and biochemical estimations. Septic ARVM displayed a distorted cell membrane and irregular network within the cells along with increased cell contractility as evidenced by elevated peak shortening (PS), maximal velocity of shortening (+dL/dt) and relengthening (-dL/dt) in comparison to sham ARVM. BigET-1 treatment caused ARVM enlargement in both sham and sepsis groups. BigET-1 (100 nM) produced an increase in ARVM contractility in sham group as compared to vehicle treatment. However, septic ARVM treated with bigET-1 exhibited unaltered ARVM contractility, and upregulated ET(B) receptors as compared to respective sham group. BigET-1 increased the concentration of ET-1 and upregulated phosphorylation of p38-MAPK but not of ERK1/2 in sham and septic ARVM. Furthermore, inhibition of p38-MAPK by SB203580 (10 microM) increased ARVM contractility in sham but not in sepsis group. BigET-1 reversed SB203580-induced increase in PS in sham group but accentuated it in sepsis group. BigET-1 also reversed SB203580-induced inhibition of p38-MAPK phosphorylation in sham but not in septic ARVM. SB203580 pretreatment followed by bigET-1 administration significantly decreased p38-MAPK phosphorylation and downregulated ET(B) receptor expression as compared to bigET-1 treatment per se in sepsis group but not in sham. We concluded that a bigET-1-induced non-responsive effect on septic ARVM contractile function could be due to upregulation of p38-MAPK phosphorylation and ET(B) receptor expression.

Topics: Animals; Endothelin-1; Heart Ventricles; Male; Myocardial Contraction; Myocytes, Cardiac; p38 Mitogen-Activated Protein Kinases; Rats; Rats, Sprague-Dawley; Sepsis

Severe sepsis is associated with increased total peripheral resistance (TPR) and decreased organ blood flow, in which endothelin-1 (ET-1) plays an important role. Plasma levels of ghrelin, a newly-identified endogenous ligand for growth hormone secretagogue receptor and a potent vasodilatory peptide, are significantly reduced in sepsis. Ghrelin downregulation heralds the hypodynamic response in severe sepsis. Therefore, we hypothesized that the administration of exogenous ghrelin improves organ blood flow by downregulation of ET-1 under such conditions.. Male adult Sprague-Dawley rats were subjected to sepsis by cecal ligation and puncture (CLP). At 5 h post-CLP, a bolus intravenous injection of 2 nmol ghrelin was followed by a continuous infusion of 12 nmol ghrelin via a primed mini-pump over 15 h. At 20 h post-CLP (i.e., severe sepsis), cardiac output (CO), stroke volume (SV), TPR, and organ blood flow were measured using (141)Ce-microspheres. Plasma ET-1 levels and preproET-1 gene expression in the liver, small intestine, and kidneys were measured by ELISA and RT-PCR, respectively. The direct effect of ghrelin on ET-1 production was studied using cultured human umbilical vein endothelial cells (HUVECs) treated with tumor necrosis factor-alpha (TNF-alpha).. Ghrelin administration reduced TPR, increased CO, SV, and organ blood flow, downregulated preproET-1 gene expression, and decreased plasma levels of ET-1 in sepsis. Ghrelin inhibited TNF-alpha-induced ET-1 release from HUVECs in a dose-dependent manner. Moreover, ghrelin inhibited TNF-alpha-induced activation of nuclear factor-kappaB (NF-kappaB) in HUVECs.. The improvement of tissue perfusion by ghrelin in severe sepsis appears to be mediated by downregulation of ET-1 involving a NF-kappaB-dependent pathway.

Topics: Acute Disease; Animals; Cells, Cultured; Colonic Diseases; Down-Regulation; Endothelial Cells; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Ghrelin; Infusions, Intravenous; Intestine, Small; Kidney; Liver; Male; Microspheres; NF-kappa B; Peptide Hormones; Perfusion; Rats; Rats, Sprague-Dawley; Regional Blood Flow; Reverse Transcriptase Polymerase Chain Reaction; Sepsis; Tumor Necrosis Factor-alpha

Trauma and subsequent sepsis lead to hepatic microcirculation disruption through various molecular mechanisms in which endothelin-1 (ET-1) plays a pivotal role. These stresses are thought to alter hepatic perfusion, heterogeneously leading to a mismatch of oxygen supply and demand. We hypothesize that mild remote stresses prime the liver to sequential sepsis through direct effects on the hepatic lobular flow distribution. We also propose to investigate the extent and the localization of the stress-induced microcirculation disruption. Sprague-Dawley rats were randomly divided into four experimental groups: sham, femur fracture (FFX), cecal ligation and puncture (CLP), and sequential stress (SS). Hepatic intravital microscopy was performed for in vivo assessment of the liver microcirculation flow distribution under baseline and after ET-1 infusion. Red blood cell motion distribution was used to quantify intralobular and interlobular heterogeneity of perfusion (HoP). Intralobular HoP, which reflects lobular regulation sites, was significantly increased in the FFX and CLP groups, but was not changed or decreased in the SS group compared with control. ET-1 infusion exerted opposite effects depending on the pathological condition, further increasing the difference between groups. SS induced decrease in intralobular HoP, contrasted with a significant increase in interlobular HoP, suggesting multiple disruption sites. Our data suggest that increased intralobular HoP may be indicative of a compensatory response to moderate stress; its decrease under sequential stress conditions corresponds with a total breakdown of hepatic lobular flow regulation. This may be another instance of the rich variability characteristic of normal physiology that "decomplexifies" under critical decompensated conditions.

Topics: Animals; Automation; Blood Flow Velocity; Cell Survival; Endothelin-1; Erythrocytes; Femur; Fracture Healing; Image Processing, Computer-Assisted; Liver; Liver Circulation; Male; Microcirculation; Perfusion; Rats; Rats, Sprague-Dawley; Sepsis; Time Factors; Wound Healing

Sepsis is the leading cause of death in critically ill surgical patients. Septic hepatic dysfunction, an important determinant of outcome, although poorly understood, includes inappropriate expression of vasoregulatory genes. In this study the effect of alpha-tocopherol was determined on the expression of hepatic vascular stress genes in response to sepsis. Rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). Rats received either vehicle or alpha-tocopherol (AT, 15 mg/kg), intraperitoneally injected for 3 d prior to CLP procedure. Serum aminotransferase activities and hepatic lipid peroxides levels markedly increased 24 h after CLP, and this rise was attenuated by AT treatment. The hepatic concentrations of reduced glutathione decreased in CLP animals, which was inhibited by AT. CLP significantly increased mRNA levels of endothelin (ET)-1 and ET(B) receptor in livers, which was not prevented by AT treatment. There were no significant changes in ET(A) mRNA expression among any of the experimental groups. There were significant increases in the mRNA expression of inducible nitric oxide synthase and heme oxygenase-1 in livers of CLP animals, and this was prevented by AT treatment. The expression of tumor necrosis factor-alpha and cyclooxygenase-2 mRNA increased 4.9-fold and 4.4-fold, respectively, in livers of CLP animals. This increase was attenuated by AT treatment. Our data suggest that sepsis induces an imbalance in hepatic vasoregulatory gene expression and that AT ameliorates altered expression of vasodilators through its free radical scavenging activity.

Topics: alpha-Tocopherol; Animals; Antioxidants; Cyclooxygenase 2; Endothelin-1; Gene Expression Regulation; Heme Oxygenase-1; Liver; Male; Nitric Oxide Synthase Type II; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Receptor, Endothelin B; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sepsis; Tumor Necrosis Factor-alpha; Vasodilation

The aim of this study was to investigate the effects of ascorbic acid on hepatic vasoregulatory gene expression during polymicrobial sepsis. Rats were subjected to polymicrobial sepsis by cecal ligation and puncture (CLP). Rats received either vehicle (n = 10) or ascorbic acid (AA, 100 mg/kg, n = 10) intravenously immediately after the CLP procedure. Serum aminotransferase levels and hepatic lipid peroxides markedly increased 24 h after CLP and this increase was attenuated by AA treatment. The hepatic concentrations of reduced glutathione decreased in CLP animals. This decrease was inhibited by AA. CLP significantly increased the mRNA level of ET-1 (p < 0.01) and ETB receptor (p < 0.01) in livers; an increase that was prevented by AA treatment. There were no significant changes in ETA mRNA expression among any of the experimental groups. There were significant increases in the mRNA expression of nitric oxide synthases (p < 0.01) and heme oxygenase-1 (p < 0.01) in livers from CLP animals. This increase was prevented by AA treatment. The expression of tumor necrosis factor-alpha and cyclooxygenase-2 mRNAs significantly increased 4.9-fold (p < 0.01) and 4.4-fold (p < 0.01) in livers from CLP animals, respectively. This increase was attenuated by AA treatment. Our data suggest that AA reduces oxidative stress and lipid peroxidation, regulates the hepatic vasoregulatory gene expression in polymicrobial sepsis and thus it could reduce hepatic microvascular dysfunction during sepsis.

Topics: Analysis of Variance; Animals; Ascorbic Acid; Cyclooxygenase 2; DNA Primers; Endothelin-1; Gene Expression Regulation; Glutathione; Isoenzymes; Lipid Peroxidation; Liver; Male; Oxidative Stress; Prostaglandin-Endoperoxide Synthases; Rats; Receptors, Endothelin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Sepsis; Transaminases; Tumor Necrosis Factor-alpha

We hypothesized that sepsis during hyperglycemia would activate left ventricular (LV) mitogen activated protein kinase (MAPK) signaling mechanisms and modulate generation of endothelin-1 (ET-1) and nitric oxide (NO) that can contribute to the progression of LV dysfunction. A single injection of streptozotocin (STZ, 60 mg/kg, via tail vein) was used to produce type 2 diabetes in male SD rats. Polymicrobial sepsis and sham-sepsis were induced using single i.p. injection of cecal inoculum and sterile 5% dextrose water, respectively, on the 13th and 27th day following STZ injection. Both 2-week (2-wk) and 4-wk diabetes groups were associated with hyperglycemia and weight loss. LV end diastolic pressure (LVEDP) was significantly increased in 4-wk diabetes but not in 2-wk diabetes group. Plasma concentration of tumor necrosis factor-alpha (TNF-alpha) was significantly increased in 4-wk diabetes+sepsis group as compared to sham, 2-wk diabetes+sepsis and sepsis groups. Elevated plasma and LV ET-1 and NO byproducts (NOx) along with LV preproET-1 and inducible nitric oxide synthase (iNOS) protein expression were observed in 4-wk but not in 2-wk diabetes group. Sepsis further elevated LV iNOS and preproET-1 in 4-wk diabetes group. Up-regulated phosphorylation of LV p38-MAPK, extracellular signal-regulated kinase 1/2 (ERK1/2) and heat shock protein-27 (Hsp27) was observed in 4-wk diabetes group. Sepsis caused a factorial increase in LV p38-MAPK and Hsp27 phosphorylation and iNOS up-regulation but not ERK1/2 following progression from 2-wk to 4-wk diabetes. The study provides evidence that sepsis up-regulated LV iNOS, p38-MAPK phosphorylation and elevated LVEDP during 4-wk diabetes. We concluded that sepsis contributes in the development of LVEDP dysfunction and alteration in signaling mechanisms depending upon the progression from 2-wk to 4-wk diabetes in the rat.

Topics: Animals; Blood Pressure; Diabetes Mellitus, Experimental; Endothelin-1; Hyperglycemia; Male; Mitogen-Activated Protein Kinases; Myocardium; Nitric Oxide; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Protein Precursors; Rats; Rats, Sprague-Dawley; Sepsis; Signal Transduction; Time Factors; Tumor Necrosis Factor-alpha; Ventricular Dysfunction, Left

To determine whether plasma endothelin-1 (ET-1) relates to clinical manifestations of sepsis in the newborn, especially with systemic hypotension, acidosis, severe hypoxemia (which may represent pulmonary hypertension) and oliguria.. Prospective study of 35 consecutive newborns with clinical sepsis: 22 with hemoculture-positive (HC+) sepsis and 13 hemoculture-negative (HC-). Plasma ET-1 concentrations were measured within 2 days of the diagnosis of sepsis. SNAP-II severity score was performed at the time of highest clinical severity.. Newborns with HC+ sepsis had higher plasma ET-1 concentrations and SNAP-II scores (especially PO 2 /FiO 2 ratio) than HC- septic children. Plasma ET-1 concentrations increased linearly with each item of the SNAP-II score, but only reached significant differences in lowest mean blood pressure (P=0.030), lowest pH (P=0.048), multiple seizures (P=0.010) and lowest urine output (P=0.013). Leukocyte count, immature/total neutrophil ratio and C-reactive protein value were not different. Each item of the SNAP-II score was independently related only to ET-1 level. Oliguria, acidosis and systemic hypotension were more correlated (R 2 >0.5).. Plasma ET-1 levels in neonatal sepsis are related to the severity of clinical manifestations, especially oliguria, acidosis and systemic hypotension.

Topics: Acidosis; Candida; Endothelin-1; Female; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Hypotension; Infant, Newborn; Infant, Newborn, Diseases; Intensive Care Units, Neonatal; Male; Oliguria; Predictive Value of Tests; Prospective Studies; Sepsis; Severity of Illness Index; Spain

To determine the changes in plasma nitrite/nitrate (NOx) and endothelin-1 (ET-1) concentrations during neonatal sepsis.. In a prospective study, 60 consecutive newborns meeting the criteria for sepsis and without receiving exogenous nitric oxide (25 haemoculture-positive [HC+] and 35 haemoculture-negative [HC-]) were compared with 68 healthy newborns (46 full-term and 22 preterm). NOx and ET-1 concentrations were measured in each newborn within 48 h of diagnosis of sepsis and then every third day up to three determinations. SNAP-II and SNAPPE-II severity scores were performed at the moment of highest clinical severity.. At the beginning of the sepsis period, controls and septicaemic newborns had similar NOx and ET-1 levels, with the exception of infants with severe HC+ sepsis. Throughout the sepsis period, NOx increased in moderate HC+ sepsis and decreased in HC--sepsis, reaching a significant difference at the end of the study period (59.9 +/- 72.7 vs 33.9 15.3 micromol/L; p = 0.036). Meanwhile, ET-1 in newborns with severe HC+ sepsis remained higher than that in the moderate HC+ sepsis group and HC--group, reaching significant differences in all the periods. The highest ET-1 value was positively correlated with SNAP-II and SNAPPE-II scores.. NOx concentrations increased throughout the neonatal HC+ sepsis period, reaching significant differences after 7-9 d. The highest ET-1 levels in neonatal HC+ sepsis emerged before the NOx peak, at 3-5 d, and later decreased. Only newborns with severe HC+ sepsis presented a significant increase in ET-1 concentrations from the beginning of the septicaemic process.

Topics: Birth Weight; Endothelin-1; Female; Gestational Age; Humans; Infant, Newborn; Male; Nitrates; Nitrites; Prospective Studies; Sepsis; Severity of Illness Index; Time Factors

We conducted this study to elucidate the role of endothelins (ET-1) in mediating the hepatic microcirculatory dysfunction observed in response to sepsis. Following 24 h of cecal ligation and puncture (CLP), we performed intravital microscopy both in vivo and on isolated perfused livers. Portal resistance increased in response to ET-1 in both sham and septic rats, with no significant difference between the two in either in vivo or in isolated livers. Sinusoidal volumetric flow (Qs) was evaluated using red blood cell velocity (V(RBC)) and sinusoidal diameter (Ds) to determine microvascular hemodynamic integrity. Qs decreased in response to ET-1 in livers from CLP rats compared with sham (P < 0.05, CLP vs. sham) in both in vivo and isolated livers. In vivo infusion of ET-1 resulted in greater constriction of sinusoids in the CLP group compared with sham (P < 0.05), resulting in higher sinusoidal resistance. Microvascular hyper-responsiveness was accompanied by hepatocellular injury in CLP rats, but not in sham rats. RT-PCR was performed to measure mRNA levels of ET-1, its receptors ET(A) and ET(B), inducible and constitutive nitric oxide (NO) synthase (iNOS and eNOS, respectively), and heme oxygenase 1 (HO-1). After CLP, both ET-1 and ET(B) mRNA increased, whereas ET(A) mRNA tended to decrease, although the change was not statistically significant. Livers from CLP rats showed no significant change in levels of eNOS mRNA, but showed a significant increase in iNOS expression (13.5-fold over sham). There was no change in the level of HO-1 mRNA between sham and CLP groups. Taken together, these results suggest that sepsis sensitizes the hepatic microcirculation to ET-1. More importantly, an impaired microcirculatory flow due to ET-1 in sepsis contributes to hepatic injury. Further, localized imbalances between endothelins and NO may mediate the altered microvascular response during sepsis.

Topics: Alanine Transaminase; Animals; Endothelin-1; In Vitro Techniques; Liver Circulation; Male; Microcirculation; Nitric Oxide; Perfusion; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; RNA, Messenger; Sepsis

Topics: Adrenomedullin; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Coronary Circulation; Endothelin-1; Glycopeptides; Humans; Lung; Peptides; Rats; Sepsis

Despite the fact that gram-positive infections constitute around 50% of all cases leading to septic shock, little is yet known about the mechanisms involved. This study was carried out to find out more about the effects of cell wall components peptidoglycan (PepG) and lipoteichoic acid (LTA) of the gram-positive bacterium Streptococcus pyogenes in the pig. Specific pathogen-free pigs (20 kg bodyweight) were pretreated with metyrapone (a cortisol-synthesis inhibitor) and then were given 2-h infusions of 160 microg/kg of PepG (n = 5), 160 microg/kg LTA (n=5), or a combination of both (LTA + PepG, 160 microg/kg each, n = 5). Four hours after start of the infusions, the PepG, LTA, and LTA + PepG groups showed decreases in mean arterial pressure (change of -11%, -25%, and -47% from baseline, respectively), dynamic lung compliance (-18%, -24%, and -38%), arterial oxygen tension (-10%, -16%, and -37%), changes in blood leukocyte numbers (+11%, -27%, and -67%), and increases in pulmonary vascular resistance index (+7%, +106%, and +307% from baseline) and metabolic acidosis (base excess values decreased with 1.8, 2.3 and 8.1 units). The differences between the PepG and LTA + PepG groups were statistically significant (P < 0.05, Kruskal-Wallis tests), but not between LTA and LTA + PepG groups. However, no changes in systemic nitric oxide (NO) production could be detected, which is much in contrast to studies on lower order animals. Moreover, comparison of the results obtained using this model with those obtained in a model of endotoxin-induced septic shock showed distinct difference in the mechanisms by which gram-positive and gram-negative bacterial components exert their actions. For example, a marked fall in systemic blood pressure and dynamic lung compliance is seen in both models, but in the present gram-positive sepsis model, much less interleukin-8 and tumor necrosis factor-alpha are produced. In conclusion, this study showed that PepG and LTA act synergistically to cause respiratory failure and septic shock in the pig. The infusion of the combination of PepG and LTA in the pig could serve as a new, well-controlled model for studies of gram-positive sepsis.

Topics: Animals; Drug Synergism; Endothelin-1; Endotoxins; Female; Hydrocortisone; Interleukin-8; Leukocyte Count; Lipopolysaccharides; Lung Compliance; Male; Metyrapone; Nitric Oxide; Oxygen; Peptidoglycan; Pulmonary Circulation; Sepsis; Shock, Septic; Specific Pathogen-Free Organisms; Streptococcus pyogenes; Swine; Teichoic Acids; Tumor Necrosis Factor-alpha; Vascular Resistance

We studied whether plasma endothelin (ET)-1 concentrations are altered in patients with septic shock who are undergoing hemodialysis and whether polymyxin B-immobilized fiber (PMX-F) treatment affects on these concentrations. Fifteen hemodialysis patients with septic shock treated with PMX-F (group A), 10 such patients who received conventional treatments (group B), 20 hemodialysis patients without septic shock (group C) and 20 healthy controls (group D) were included in this study. Plasma ET1 levels were measured by radioimmunoassay and endotoxin levels were determined by endospecy test. The survival rate in group A (67%) was higher than that in group B (30%). Blood endotoxin levels decreased significantly from 36.4+/-8.2 pg/mL to 10.6+/-3.8 pg/mL (p < 0.01) after PMX-F treatment in group A. The pretreatment plasma ET-1 levels in patients in group A (58.6+/-9.8 pg/mL) and group B (56.8+/-7.8 pg/mL) were significantly higher than those in group C (p < 0.01) and group D (p < 0.001). Plasma ET-1 levels in group C (11.2+/-3.2 pg/mL) were higher than those in group D (2.6+/-0.6 pg/mL) (p < 0.01). Plasma ET-1 levels following hemodialysis (10.9+/-3.0 pg/mL) were not altered significantly compared with those before hemodialysis. Plasma ET-1 levels decreased significantly in group A after PMX-F treatment (11.4+/-3.6 pg/mL) (p < 0.01); the levels in group B were not altered after conventional treatment. Our data suggest that ET-1 may be associated with septic shock in patients undergoing hemodialysis and that PMX-F is effective in reducing plasma ET-1 levels in these patients.

Topics: Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents; Biomarkers; Endothelin-1; Humans; Membranes, Artificial; Middle Aged; Polymyxin B; Radioimmunoassay; Renal Dialysis; Retrospective Studies; Sepsis; Treatment Outcome

Polymicrobial sepsis is characterized by an early, hyperdynamic phase followed by a late, hypodynamic phase. Although studies have suggested that endothelins (ETs) contribute to the development of shock after a bolus injection of endotoxin, little is known about the role of ETs in the transition from the hyperdynamic phase to the hypodynamic phase of sepsis. To study this, male adult rats were subjected to sepsis by cecal ligation and puncture (CLP) followed by fluid resuscitation. Plasma levels of ET-1 and ET-2 were measured by radioimmunoassay at 2, 5, 10 h (i.e. the early stage of sepsis), and 20 h (late stage) following CLP or sham operation. Tissue levels of ET-1 and ET-2 were determined in the heart, lungs, small intestine, and spleen at 5 h after CLP or sham operation. In addition, preproendothelin-1 (precursor of ET-1) gene expression was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) at 5 h in the heart, lungs, small intestine, spleen, and liver. The results indicate that plasma levels of ET-1 and ET-2 were not different from values of sham groups at 2 and 20 h, but were significantly higher than the sham values at 5 and 10 h after CLP. While there were no significant increases in tissue levels of ET-1 and ET-2 at 5 h post-CLP, RT-PCR analysis indicates a significant upregulation of preproendothelin-1 gene expression in the heart, spleen, and liver (but not in the lungs or small intestine) at 5 h after the onset of sepsis. These results indicate that the heart, spleen, and liver appear to be important ET-producing organs during the early stage of sepsis. The lack of significant increases in tissue ET levels could be due to the possibility that the newly converted peptide is quickly transferred to the bloodstream. Since the hyperdynamic phase of sepsis occurs at 2-10 h and the hypodynamic phase occurs at 20 h after CLP, the increased plasma levels of ET at 5 and 10 h suggest that mediators other than ETs (such as adrenomedullin) are responsible for producing the biphasic hemodynamic responses during the progression of polymicrobial sepsis.

Topics: Animals; Cecum; Endothelin-1; Endothelins; Hemodynamics; Male; Protein Precursors; Rats; Rats, Sprague-Dawley; RNA, Messenger; Sepsis; Time Factors

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

Topics: Animals; Endothelin-1; Gram-Positive Bacterial Infections; Humans; Nitric Oxide; Nitric Oxide Synthase; Sepsis; Shock, Septic

Topics: Animals; Disease Models, Animal; Endothelin-1; Hemodynamics; Humans; Inflammation; Rats; Sepsis

Pyridoxalated hemoglobin polyoxyethylene conjugate (PHP), a nitric oxide scavenger, causes systemic and pulmonary vasoconstriction in normal and septic sheep. We studied the effect of L-arginine and the endothelin-1 (ET-1) antagonist bosentan on the PHP response to determine whether the PHP-induced vasoconstriction resulted predominantly from the action of ET-1 or solely from removal of NO. After 24 h of carrier solution (nonseptic sheep), sheep received PHP (20 mg/kg/h; n = 5), PHP plus L-arginine (at 28 h, 100 mg/kg bolus and 500 mg/kg for 1 h) plus bosentan (at 32 h, 10 mg/kg; n = 6), and only L-arginine and bosentan (n = 5). These protocols were repeated after 24 h of Pseudomonas aeruginosa (S, 6x10(6) colony-forming units/kg/h). PHP induced vasoconstriction in septic and nonseptic sheep for the duration of its infusion. In nonseptic sheep, neither L-arginine nor bosentan significantly lowered systemic (SVRI) and pulmonary (PVRI) vascular resistance and did not antagonize the PHP-induced vasoconstriction. During sepsis, SVRI fell and cardiac index (CI) rose. L-arginine and bosentan further decreased SVRI (L-arginine: 34+/-2%*, p<.05; bosentan: 35+/-5%*, p<.05) and PVRI (L-arginine: 28+/-2%*, p<.05; bosentan: 33+/-7%*, p<.05) and increased CI (L-arginine: 29+/-4%*, p<.05; bosentan: 11+/-5%, NS). Both agents antagonized the PHP-induced vasoconstriction lowering SVRI (L-arginine: 29+/-3%*, p<.05; bosentan: 26+/-5%*, p<.05) and PVRI (L-arginine: 27+/-4%*, p<.05; bosentan: 32+/-4%*, p<.05) to levels before PHP administration. Plasma ET-1 levels increased during sepsis (from 9.8+/-.2 to 15.6+/-.7* pg/mL, p<.05) and fell during PHP infusion (to 9.7+/-1.6* pg/mL, p<.05). In nonseptic sheep, ET-1 levels decreased during PHP (from 8.5+/-.6 pg/mL to 5.9+/-.6*, p<.05). Bosentan increased ET-1 levels 2.7 times higher in septic than in nonseptic sheep. We conclude that during sepsis, the NO scavenger PHP unmasks an underlying ET-1 mediated vasoconstriction, and its effect is antagonized by L-arginine and bosentan.

Topics: Animals; Antihypertensive Agents; Arginine; Blood Substitutes; Bosentan; Endothelin Receptor Antagonists; Endothelin-1; Female; Hemodynamics; Hemoglobins; Nitric Oxide; Polyethylene Glycols; Sepsis; Sheep; Sulfonamides; Vasoconstriction

This study was performed to integratively investigate the vasoregulatory response during standardized splanchnic hypoperfusion in pigs. Splanchnic perfusion was reduced to 50% of baseline by: haemorrhage by 20 and 40% of the estimated total blood volume; femoral venous infusion of live E. coli to establish sepsis of systemic origin; portal venous infusion of live E. coli to establish sepsis of splanchnic origin. Invasive haemodynamic monitoring and radioimmunoassay analyses of arterial plasma concentrations of angiotensin II, endothelin-1 and atrial natriuretic peptide were carried out. Acute hypovolaemia reduced systemic and splanchnic vascular resistances following transient increases and increased angiotensin II levels (+587%), whereas endothelin-1 and atrial natriuretic peptide levels did not change significantly. Systemic sepsis following femoral venous infusion of E. coli resulted in increased splanchnic vascular resistance and increased levels of angiotensin II (+274%), endothelin-1 (+134%) and atrial natriuretic peptide (+185%). Infusion of E. coli via the portal venous route induced an increase in splanchnic vascular resistance associated with particularly elevated levels of angiotensin II (+1770%) as well as increased endothelin-1 (+201%) and atrial natriuretic peptide (+229%) concentrations. Hypovolaemia and sepsis, although standardized with a predefined level of splanchnic hypoperfusion, elicited differentiated cardiovascular and vasopeptidergic responses. Sepsis, particularly of portal origin, notably increased splanchnic vascular resistance related to increased production of the vasoconstrictors angiotensin II and endothelin-1. The role of atrial natriuretic peptide as a vasodilator seems to be of subordinate importance in hypovolaemia and sepsis.

Topics: Acute Disease; Anesthesia; Angiotensin II; Animals; Atrial Natriuretic Factor; Endothelin-1; Escherichia coli Infections; Female; Femoral Vein; Hemorrhage; Hypovolemia; Male; Neuropeptides; Portal Vein; Sepsis; Splanchnic Circulation; Swine; Vasoconstrictor Agents

Recently much attention has been paid to the circulatory disturbance and peripheral vascular damage in patients with sepsis and septic shock. We intended to elucidate the interaction between nitric oxide (NO) and endothelin (ET)-1 under various pathological conditions by measuring the concentrations of NO3-, the principal metabolite of NO and immunoreactive ET-1. In cases with good prognosis after the septic shock, ET-1 was significantly higher as compared with these in sepsis without shock. In lethal cases with septic shock, these parameters were abnormally high as compared with the survived case. These levels elevated as the degree of severity progressed. When patients recovered from the septic shock, plasma ET-1 levels rapidly decreased. These results may mean that the level of the concentration of ET-1 plays a key role for prevention of the multiple organ failure even after the recovery from septic shock. The elevated level of NO3- during the initial several days in septic shock will mean that NO is acting to prevent platelet aggregation and to keep blood flow by dilating the arteries during septic shock. On the contrary, it may also be suggested that the elevated level of NO3- and ET-1 leads to the dysfunction of vascular endothelial cells and the apoptosis.

Topics: Adult; Biomarkers; Endothelin-1; Female; Humans; Male; Middle Aged; Multiple Organ Failure; Nitric Oxide; Prognosis; Sepsis; Severity of Illness Index; Shock, Septic

Our objective was to investigate the significance of endogenous endothelin-1-induced systemic circulatory reactions during hypodynamic sepsis. In the first part of this study, we observed the changes in global hemodynamic parameters in Wistar rats after exogenous endothelin-1 administration in order to test an intervention strategy aimed at preventing the development of hypodynamic cardiovascular derangement during intraabdominal sepsis. Cardiac output, mean arterial blood pressure, and peripheral vascular resistance were recorded, and the endothelin-A receptor antagonist BQ-610 and the endothelin-B receptor antagonist IRL-1038 were used to investigate the role of receptor subtypes in circulatory changes. In addition, the effects of treatment with the novel endothelin-A receptor inhibitor ETR-P1/fl peptide were examined in endothelin-1-treated anesthetized rats. The injection of 1 nmol/kg endothelin-1 induced a significant rise in peripheral vascular resistance, a transient increase in mean arterial pressure, and a decrease in cardiac output. Administration of the endothelin-A receptor antagonist BQ-610 and ETR-P1/fl peptide increased cardiac output and decreased systemic vascular resistance in the controls and in animals treated with exogenous endothelin. In the second part of the study, the animals were instrumented for hemodynamic monitoring and randomized to undergo cecal ligation and perforation for 8 h or control laparotomy. Septic animals with cecal ligation and puncture were normotensive and hypodynamic, with a significantly increased total peripheral resistance throughout the 8 h observation period. ETR-P1/fl peptide treatment started after the induction of sepsis significantly increased cardiac output and decreased systemic vascular resistance almost to control levels. We conclude that endogenous endothelin-1 contributes significantly to the systemic hemodynamic alterations during hypodynamic circulatory response, and the inhibition of endothelin-A receptors may improve global hemodynamic status in this phase of sepsis.

Topics: Amino Acid Sequence; Animals; Blood Pressure; Cardiac Output; Cecum; Endothelin Receptor Antagonists; Endothelin-1; Endothelins; Hemodynamics; Intercellular Signaling Peptides and Proteins; Male; Molecular Sequence Data; Oligopeptides; Peptide Fragments; Peptides; Rats; Rats, Wistar; Receptor, Endothelin A; Receptor, Endothelin B; Receptors, Endothelin; Sepsis; Vascular Resistance

This experiment was designed to help understand the cascade of events that end in renal impairment in septic animals.. Twenty 3- to 8-day-old piglets were anesthetized and the femoral artery, jugular and femoral veins, and bladder were catheterized. After stabilization under anesthesia with ventilatory support, they were divided into a control group and three groups that received endotoxin (ETX) in doses of 0.01 mg/kg, 0.025 mg/kg, and 0.05 mg/kg. Blood pressure and blood gases were monitored continuously. Blood and urine samples were obtained before (B), 1 hour (E1), and 3 hours (E3) after the bolus of ETX to determine glomerular filtration rate (GFR), fractional excretion of sodium (FENa), tumor necrosis factor (TNF), and endothelin-1 (ET-1) levels.. Incremental doses of ETX induce greater release of ET-1 with an early proportionate increase in FENa (P< .05) and late decrease in GFR (P< .05). TNF release is dose and time dependent after ETX injection (P < .05).. ET-1 and FENa are the best tests to evaluate renal failure during early sepsis in neonatal piglets.

Topics: Acute Kidney Injury; Animals; Animals, Newborn; Endothelin-1; Multiple Organ Failure; Sepsis; Sodium; Swine; Tumor Necrosis Factor-alpha

Hemoperfusion using polymyxin B-immobilized fiber (PMX-F) is reported to be an effective treatment for sepsis. The aim of the present study is to assess whether plasma endothelin-1 (ET-1) and ET-1 messenger RNA (mRNA) levels in peripheral-blood monocytes are altered in patients with sepsis and whether PMX-F treatment affects plasma ET-1 and monocyte ET-1 mRNA levels. Sixteen patients with sepsis and 20 healthy volunteers were included in this study. Plasma ET-1 concentration was measured by radioimmunoassay (RIA), and plasma levels of transforming growth factor-beta (TGF-beta), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) were measured by enzyme-linked immunosorbent assay (ELISA). Sixteen patients with sepsis were treated with direct hemoperfusion using PMX-F columns. Blood endotoxin levels decreased significantly from 35 to 10 pg/mL after two treatments of direct hemoperfusion, each for 2 hours. Patients with sepsis showed significantly increased levels of plasma ET-1 (P < 0.001) and monocyte ET-1 mRNA (P < 0.001) compared with healthy volunteers. However, no differences in plasma levels of TGF-beta, TNF-alpha, and IL-1beta existed between patients with sepsis and healthy volunteers. Increased plasma ET-1 levels and monocyte ET-1 mRNA levels in patients with sepsis decreased significantly after PMX-F treatment (P < 0.01). These data suggest that the secretion of ET-1 from peripheral-blood monocytes may be stimulated by endotoxin, and PMX-F treatment may be effective in reducing ET-1 secretion in patients with sepsis.

Topics: Adult; Aged; Anti-Bacterial Agents; APACHE; Endothelin-1; Endotoxemia; Female; Gram-Negative Bacterial Infections; Gram-Positive Bacterial Infections; Hemoperfusion; Humans; Male; Middle Aged; Monocytes; Polymyxin B; RNA, Messenger; Sepsis; Statistics, Nonparametric

The aim of this study was to determine the role of sympathetic neural activity in the hemodynamic adaptations to sepsis in pigs with an emphasis on circuit adaptations. A fall in resistance to venous return (RVR) was predicted in contrast to what was previously observed in sympathetically intact animals that had no change in RVR.. We anesthetized and ventilated 13 pigs and gave 5 mg/kg of indomethacin. We measured cardiac output (CO) by thermodilution and measured pulmonary arterial (PAP), pulmonary capillary wedge (Pcw), right atrial pressure (Pra), and arterial pressure (MAP). Intermittent inflation of a 50-mL balloon in the right atrium was used to transiently arrest the circulation for the measurement of mean circulatory filling pressure (MCFP). RVR was calculated from (MCFP - Pra)/CO. Animals were divided into two groups; 6 received 10 mg/kg of the ganglionic blocker, hexamethonium and norepinephrine to maintain MAP; 7 had their spinal cords cut at C-2. After baseline measurements, all animals received 10 microg/kg/h of endotoxin for 2 hours, and hemodynamic measurements were repeated. Plasma samples were obtained for measurements of immunoreactive endothelin-1 (ET-1), which was assayed by a radioimmunoassay.. Hexamethonium had no significant effect on hemodynamics except for an increase in heart rate. After endotoxin, MAP and SVR fell, PAP rose, and CO and RVR did not change. Spinal section resulted in an increase in heart rate and small increase in PAP and MCFR After endotoxin, there was a further increase in heart rate, PAP, and MCFP with a marked fall in MAP and CO. RVR increased from 2.1 +/- 0.46 after spinal section to 3.6 +/- 54 mm x min/L (P < .05). ET-1 in the hexamethonium group (n = 2) rose from 2.21 +/- .14 to 11.5 +/- 2.1 pg/ml at 2 hours, and in the spinal group (n = 7) from 2.04 +/- 0.77 to 6.85 +/- 3.9 pg/mL at 45 minutes.. Spinal section resulted in a more profound fall in blood pressure and less increase in MCFP than in previously studied animals with sympathetic nervous system intact, but there was still an increase in RVR and PAP ET-1 is a possible mediator of the increase in RVR and PAP.

Topics: Adaptation, Physiological; Animals; Cyclooxygenase Inhibitors; Denervation; Disease Models, Animal; Endothelin-1; Ganglionic Blockers; Hemodynamics; Hexamethonium; Indomethacin; Sepsis; Spinal Cord; Swine; Sympathetic Nervous System

Persistent vasodilation refractory to vasopressor agents is the hemodynamic abnormality characteristic of septic shock. Induction of nitric oxide synthase (NOS) by sepsis-induced cytokines has been hypothesized to play a pathogenetic role in this refractory vasodilation. To evaluate the mechanism of vasodilation in sepsis, we used in vivo videomicroscopy to measure responses of resistance arterioles (15-20 microm) to topical suffusion of the potent vasoconstrictor, endothelin-1 (ET-1), in rat cremaster muscle. Rats made septic by cecal ligation and puncture were compared with controls that underwent sham ligation. Responses to topically suffused ET-1 were assessed in septic and control rats before and after superfusion of the muscle with the NOS inhibitor N(G)-monomethyl-L-arginine (L-NMMA). Sepsis produced a decrease in ET-1-induced vasoconstriction; the ET-1 concentration-response curve was shifted to the right in septic rats (P < 0.05). Contractions at ET-1 concentrations of 1, 10, and 100 nM were 20, 28, and 32%, respectively, of sham controls. Superfusion of the muscle with L-NMMA restored arteriolar responsiveness to ET-1 in the septic rats, significantly increasing arteriolar constriction at 1 and 10 nM. This effect was reversed with superfusion of excess L-arginine (1 mM). This study demonstrates that impaired vasoconstriction in response to ET-1 in resistance arterioles of septic rats in vivo is reversed by NOS inhibition. Taken together with previous studies showing sepsis-induced impairment of vasoconstriction with norepinephrine, a vasopressor with a mechanism of action different from ET-1, these findings suggest a generalized abnormality in the responsiveness of resistance arterioles in sepsis. Reversal of hyporesponsiveness to both of these vasopressor agents by NOS inhibition suggests an important role for nitric oxide as a mediator of refractory vasodilation in sepsis.

Topics: Animals; Arterioles; Cecum; Dose-Response Relationship, Drug; Endothelin-1; Male; Microscopy, Video; Muscle, Skeletal; Nitric Oxide Synthase; Norepinephrine; omega-N-Methylarginine; Rats; Rats, Sprague-Dawley; Reference Values; Sepsis; Vasoconstriction; Vasodilation

Excessive production of nitric oxide significantly contributes to the hyperdynamic state associated with sepsis. The ability of hemoglobin to scavenge nitric oxide may therefore be beneficial in the treatment of sepsis. In this study, we determined the effects of different doses of the modified human pyridoxalated hemoglobin polyoxyethylene conjugate in an ovine model of hyperdynamic sepsis.. Prospective, experimental study.. Large animal research laboratory at a university medical center.. Sheep (n = 23) were surgically prepared for chronic study. After a 5-day recovery period, all animals received a continuous infusion of live Pseudomonas aeruginosa (2.5 x 10(6) colony-forming units/min) for the next 48 hrs. After 24 hrs of sepsis, the animals were divided into four groups: a) six sheep were used as controls and received a bolus of 200-mL vehicle; b) three sheep received a bolus of 50 mg/kg hemoglobin; c) six sheep received 100 mg/kg of hemoglobin; d) six sheep received 200 mg/kg of hemoglobin.. All animals that survived the first 24 hrs of sepsis (n = 21) developed a hyperdynamic circulation. All three doses of hemoglobin reversed this hyperdynamic state by increasing mean arterial pressure and systemic vascular resistance while decreasing cardiac index. Pulmonary arterial pressure increased after hemoglobin infusion. Increased pulmonary arterial pressure did not affect arterial oxygen saturation nor result in the development of pulmonary edema. Infusion of hemoglobin also caused a 30-fold increase in endothelin-1 plasma concentrations and significantly decreased nitrate and nitrite plasma concentrations.. The infusion of low doses of pyridoxalated hemoglobin polyoxyethylene conjugate in septic sheep reverses the hyperdynamic circulatory state. An increase in pulmonary arterial pressure was the only observed hemodynamic side effect; changes in the structure or function of other organ systems, or their biochemical correlates were not investigated in this study. In addition to a possible nitric oxide scavenging effect, pyridoxalated hemoglobin polyoxyethylene may affect the nitric oxide synthase and endothelin systems.

Topics: Animals; Blood Circulation; Blood Pressure; Blood Substitutes; Endothelin-1; Female; Hemoglobins; Nitrates; Nitrites; Polyethylene Glycols; Prospective Studies; Sepsis; Sheep; Vascular Resistance

Plasma concentrations of endothelin-1 (ET-1) and thrombomodulin (TM) were determined in patients with burns to examine their relation to the severity of illness. Tumor necrosis factor-alpha (TNF-alpha) was also measured, and its relationship to ET-1 and TM determined. Twenty-three burn patients were evaluated, who had a total burn surface area (TBSA) of at least 20 per cent. ET-1 was measured by radioimmunoassay (RIA). TM and TNF-alpha were measured by enzyme-linked immunosorbent assay (ELISA). Both the ET-1 and TM concentrations were significantly higher in the patients who developed sepsis than in those who did not and in the patients who eventually died than in those who survived. Maximum plasma concentrations of ET-1 and TM were significantly correlated with the acute physiological and chronic health evaluation II score. There was also a significant correlation between the plasma levels of TNF-alpha and both ET-1 and TM. ET-1 and TM closely reflect the severity of illness in patients with burns in the infectious stage; TNF-alpha may be involved in the production of ET-1 and TM.

Topics: Adult; Aged; APACHE; Body Surface Area; Burns; Endothelin-1; Enzyme-Linked Immunosorbent Assay; Female; Humans; Male; Middle Aged; Radioimmunoassay; Sepsis; Severity of Illness Index; Survival Rate; Thrombomodulin; Tumor Necrosis Factor-alpha; Wound Infection