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Endothelin-1 in peripheral arterial disease: a potential role in muscle damage. Pharmacol Res 2011; 63:473-6. [PMID: 21382494 DOI: 10.1016/j.phrs.2011.02.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Revised: 02/26/2011] [Accepted: 02/27/2011] [Indexed: 12/17/2022]
Abstract
The evidence for the role of endothelin-1 (ET-1) in endothelial dysfunction and atherosclerosis has been growing since its discovery. However most studies have focussed on cardiac disease and its role in peripheral arterial disease (PAD) is less clear. In addition to its role in the development and progression of atherosclerotic lesions in lower limb arteries, there is evidence that ET-1 adversely affects microvessels within the muscle and the viability of the ischemic muscle itself. This review summarises some of these findings which underscore the potential use of ET antagonists as an adjunct in the treatment of PAD.
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Mansart A, Ruff LJ, Ariaans MP, Ross JJ, Reilly CS, Brown NJ, Kaufman S, Brookes ZLS. Constriction of rat extra-splenic veins to lipopolysaccharide involves endothelin-1. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:555-62. [PMID: 20397012 DOI: 10.1007/s00210-010-0514-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 03/11/2010] [Indexed: 11/30/2022]
Abstract
The spleen has an important role in blood volume regulation and increased resistance of post-capillary hilar veins (in mesentery adjoining the spleen) can regulate this. This study investigated whether venular constriction to lipopolysaccharide (LPS) involved endothelin-1 (ET-1). Pressure myography was used to study isolated extra-splenic (hilar) vessels from male Wistar rats (n = 111). Arteries and veins were treated with LPS (50 microg ml(-1)) for 4 h. Extra-splenic veins constricted to LPS (p < 0.05), but there was no effect on arteries. Denudation did not abolish venular constriction to LPS, indicating an endothelial independent mechanism. However, the dual ET-1 receptor antagonist bosentan (10(-5) M) and specific ET(A) and ET(B) antagonists ABT-627 (atrasentan, 6.3 x 10(-6) M) and A-192621(1.45 x 10(-6) M) completely abolished constriction of LPS-treated veins. ET-1 alone also constricted the extra-splenic arteries and veins (p < 0.05), with a greater response observed in veins (p < 0.05). ELISA also confirmed that serum and spleen levels of ET-1 increased in response to LPS (p < 0.05). That LPS-induced constriction of extra-splenic veins is mediated by ET-1. Greater constriction of post- versus pre-capillary extra-splenic vessels to LPS would result in increased intra-splenic fluid extravasation and hypovolaemia in vivo.
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Affiliation(s)
- Arnaud Mansart
- Academic Unit of Anaesthesia, University of Sheffield, Royal Hallamshire Hospital, Sheffield, S10 2RX, UK
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Yao Z, Hoffman EP, Ghimbovschi S, DuBois DC, Almon RR, Jusko WJ. Pharmacodynamic/pharmacogenomic modeling of insulin resistance genes in rat muscle after methylprednisolone treatment: exploring regulatory signaling cascades. GENE REGULATION AND SYSTEMS BIOLOGY 2008; 2:141-61. [PMID: 19787081 PMCID: PMC2733097 DOI: 10.4137/grsb.s613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Corticosteroids (CS) effects on insulin resistance related genes in rat skeletal muscle were studied. In our acute study, adrenalectomized (ADX) rats were given single doses of 50 mg/kg methylprednisolone (MPL) intravenously. In our chronic study, ADX rats were implanted with Alzet mini-pumps giving zero-order release rates of 0.3 mg/kg/h MPL and sacrificed at various times up to 7 days. Total RNA was extracted from gastrocnemius muscles and hybridized to Affymetrix GeneChips. Data mining and literature searches identified 6 insulin resistance related genes which exhibited complex regulatory pathways. Insulin receptor substrate-1 (IRS-1), uncoupling protein 3 (UCP3), pyruvate dehydrogenase kinase isoenzyme 4 (PDK4), fatty acid translocase (FAT) and glycerol-3-phosphate acyltransferase (GPAT) dynamic profiles were modeled with mutual effects by calculated nuclear drug-receptor complex (DR(N)) and transcription factors. The oscillatory feature of endothelin-1 (ET-1) expression was depicted by a negative feedback loop. These integrated models provide testable quantitative hypotheses for these regulatory cascades.
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Affiliation(s)
- Zhenling Yao
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, New York 14260, USA
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Vassilakopoulos T, Hussain SNA. Ventilatory muscle activation and inflammation: cytokines, reactive oxygen species, and nitric oxide. J Appl Physiol (1985) 2007; 102:1687-95. [PMID: 17185492 DOI: 10.1152/japplphysiol.01273.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Strenuous diaphragmatic contractions that are induced by inspiratory resistive breathing initiate an inflammatory response that involves the elevation of pro- and anti-inflammatory cytokines within the diaphragm, which may then spill into the circulation. The production of reactive oxygen species within working respiratory muscles increases in response to these strenuous diaphragmatic contractions. At the same time, diaphragmatic nitric oxide (NO) production declines significantly, despite a time-dependent increase in NO synthase isoform protein expression. The increase in adhesion molecule expression and infiltration of granulocytes and macrophages that follows may contribute to the contraction-induced diaphragm injury. Enhanced generation of reactive oxygen species, oxidative stress augmentation, reduced NO production, and glycogen depletion are potential stimuli for the cytokine induction that is secondary to strenuous diaphragmatic contractions. This production of cytokines within the diaphragm may contribute to the diaphragmatic muscle fiber injury that occurs with strenuous contractions or to the expected repair process. TNF-α is a cytokine that compromises diaphragmatic contractility and may contribute to muscle wasting. IL-6 is a cytokine that may have beneficial systemic effects by mobilizing glucose from the liver and free fatty acids from the adipose tissue and providing them to the strenuously working respiratory muscles. Thus cytokine upregulation within the working diaphragm may be adaptive and maladaptive.
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Affiliation(s)
- Theodoros Vassilakopoulos
- Department of Critical Care and Pulmonary Services, University of Athens Medical School, Evangelismos Hospital, Athens, Greece
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Vassilakopoulos T, Govindaraju K, Parthenis D, Eidelman DH, Watanabe Y, Hussain SNA. Nitric oxide production in the ventilatory muscles in response to acute resistive loading. Am J Physiol Lung Cell Mol Physiol 2006; 292:L1013-22. [PMID: 17189323 DOI: 10.1152/ajplung.00112.2006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The effect of muscle activation on muscle nitric oxide (NO) production remains controversial. Whereas NO release increases in in vitro activated muscles and in vivo limb muscles, diaphragmatic NO synthase (NOS) activity declines after 3 h of inspiratory resistive loading (IRL). We tested in this study the hypotheses that acute IRL decreases diaphragmatic NO derivatives levels and reduces protein expression of neuronal (nNOS), endothelial (eNOS), and inducible (iNOS) NO synthases, as well as 3-nitrotyrosine formation. Anesthetized, tracheostomized, spontaneously breathing adult rats were subjected to IRL (50% of the maximum inspiratory pressure) for 1, 3, or 6 h. Quietly breathing rats served as controls. After 3 h of IRL, muscle eNOS and nNOS protein levels rose by 80 and 60% of control values, respectively. Whereas eNOS expression did not change any further, nNOS expression reached 550% of control values after 6 h of IRL. Strong iNOS protein expression was detected in the diaphragms after 6 h of IRL. Total NO derivatives levels in the diaphragm declined during IRL as a result of reduction in nitrate, nitrite, and nitrosothiols. Diaphragmatic protein tyrosine nitration decreased in response to IRL, and this reduction was mainly due to reduced tyrosine nitration of enolase and aldolase. We conclude that diaphragmatic NO derivatives levels decline in response to IRL and that the rise in diaphragmatic NOS protein expression may be a compensatory response designed to counterbalance the decline in NOS activity.
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Affiliation(s)
- Theodoros Vassilakopoulos
- Department of Critical Care and Pulmonary Services, University of Athens Medical School, Evangelismos Hospital, Athens, Greece
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Slomiany BL, Slomiany A. Cytosolic phospholipase A2 activation in Helicobacter pylori lipopolysaccharide-induced interference with gastric mucin synthesis. IUBMB Life 2006; 58:217-23. [PMID: 16754300 DOI: 10.1080/15216540600732021] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Release of arachidonic acid from membrane glycerophospholipids by cytosolic phospholipase A2 (cPLA2) is a key step in the generation of platelet-activating factor (PAF), recognized as the most proximal mediator of inflammatory events triggered by bacterial infection. Here, we report on the role of cPLA2 in the disturbances in gastric mucin synthesis evoked by the LPS of H. pylori, a bacterium identified as a primary cause of gastric disease. Using rat gastric mucosal cells, we show that H. pylori LPS detrimental effect on gastric mucin synthesis, associated with up-regulation in PAF and endothelin-1 (ET-1) generation, was subject to suppression by a specific inhibitor of cPLA2, MAFP. Moreover, the LPS-induced changes in mucin synthesis and ET-1 generation were countered by PAF receptor antagonist, BN52020. The impedance by PAF antagonist of the LPS-induced reduction in mucin synthesis was countered by wortmannin, an inhibitor of PI3K, as well as by ERK inhibitor, PD98059. The blockade of ERK caused also inhibition of the LPS-induced cPLA2 activation and amplification in the impedance capacity of PAF antagonist on the LPS-induced ET-1 generation, while the inhibitor of PI3K had no effect. Our findings are the first to demonstrate that the detrimental consequences of H. pylori LPS on gastric mucin synthesis involve ERK-dependent cPLA2 activation that leads to up-regulation in PAF generation and ET-1 production.
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Affiliation(s)
- Bronislaw L Slomiany
- Research Center, University of Medicine and Dentistry of New Jersey, Newark, New Jersey, USA.
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Yamaguchi N, Jesmin S, Zaedi S, Shimojo N, Maeda S, Gando S, Koyama A, Miyauchi T. Time-dependent expression of renal vaso-regulatory molecules in LPS-induced endotoxemia in rat. Peptides 2006; 27:2258-70. [PMID: 16725227 DOI: 10.1016/j.peptides.2006.03.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2005] [Revised: 03/20/2006] [Accepted: 03/22/2006] [Indexed: 10/24/2022]
Abstract
To elucidate roles of microvascular factors in the pathogenesis of renal complications during endotoxemia, that is characterized by renal vasoconstriction and systemic hypotension/generalized non-renal vasodilation, we profile the expression pattern and time-course of three key vaso-regulators, namely endothelin (ET)-1, nitric oxide (NO), and angiotensin II (Ang II). We hypothesize that disruption of the overall balance between vasodilatation and vasoconstriction in the kidney, during the early phase of sepsis, contribute to its (kidney) predisposition to acute renal failure. Adult male Wistar rats were rendered endotoxemic at different time points (1, 3, 6 and 10 h) by a single i.p. injection of lipopolysaccharide (LPS) (15 mg/kg) dissolved in saline. Control group was injected vehicle only (saline). Both systolic and diastolic blood pressures significantly decreased at different time points after LPS administration. Surprisingly, renal histopathological evaluation showed no remarkable changes in LPS-induced endotoxemia. However, overall, levels of the vaso-regulators and, where applicable, their respective receptors were upregulated: (1) plasma ET-1 increased 25-fold and peaked, as renal ET-1 mRNA, at 3 h; renal ET-1 protein and its receptors, ET type A (ET(A)) receptor (vasoconstrictive) and ET type B (ET(B)) receptor (vasodilatatory) increased in a time-dependent fashion, (2) Ang II increased by 53% compared to control, peaking at 6 h. However, while levels of Ang II type 1 (AT1) receptor increased over time after LPS injection, those of Ang II type 2 (AT2) receptor were downregulated, (3) data of NO system (NO-NOS), the key vasodilator, were the most intriguing. Whereas levels of renal NO increased time-dependently following LPS administration, with a 2240-fold increase in renal iNOS expression, levels of eNOS, were almost unchanged. In conclusion, the present study overall reveals intriguing and complex dynamics between levels of vasoconstrictors and vasodilators during the early phase of LPS-induced endotoxemia. These shifts in molecular expressions are likely triggered by compensatory mechanisms aimed at counteracting the undesirable and dominant effects of one group of vaso-regulatory moiety over the other.
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Affiliation(s)
- Naoto Yamaguchi
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki 300-0394, Japan
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Slomiany BL, Slomiany A. Up-regulation in endothelin-1 by Helicobacter pylori lipopolysaccharide interferes with gastric mucin synthesis via epidermal growth factor receptor transactivation. Scand J Gastroenterol 2005; 40:921-28. [PMID: 16173126 DOI: 10.1080/00365520510015890] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Endothelin-1 (ET-1), a key mediator of inflammatory processes associated with bacterial infection, is a 21-amino acid peptide produced from a biologically inactive big ET-1 by the action of endothelin-converting enzyme-1 (ECE-1) that acts through G protein-coupled ET(A) and ET(B) receptors. Here we report on the role of ET-1 in the mediation of the detrimental influence of Helicobacter pylori on the synthesis of gastric mucin. MATERIAL AND METHODS Rat gastric mucosal cells were exposed to H. pylori key virulence factor, lipopolysaccharide (LPS). RESULTS The LPS inhibitory effect on gastric mucin synthesis was accompanied by a marked increase in ET-1 generation and enhancement in ECE-1 activity. Inhibition of ECE-1 with phosphoramidon not only led to the impedance of LPS-induced ET-1 generation, but also countered the detrimental effect of LPS on mucin synthesis. Moreover, the LPS inhibitory effect on mucin synthesis was blocked by ET(A) receptor antagonist BQ610, but not by ET(B) receptor antagonist BQ788. Furthermore, the LPS-induced suppression in gastric mucin synthesis was countered in a concentration-dependent fashion by PD153035 (81.7%), a specific inhibitor of epidermal growth factor receptor (EGFR) kinase as well as PP2 (69.8%), a selective inhibitor of tyrosine kinase Src responsible for ligand-independent EGFR transactivation. CONCLUSIONS Our findings are the first to show that the detrimental effect of H. pylori on gastric mucin synthesis is intimately linked to the events associated with ECE-1 up-regulation, enhancement in ET-1 production, and G protein-coupled ET(A) receptor activation that triggers the EGFR transactivation.
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Affiliation(s)
- Bronislaw L Slomiany
- Research Center, C875, UMDJN-NJ Dental School, 110 Bergen Street, P.O. Box 1709, Newark, NJ 07103-2400, USA.
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Slomiany BL, Slomiany A. Role of Leptin in Modulation of Porphyromonas gingivalis Lipopolysaccharide-induced Up-regulation of Endothelin-1 in Salivary Gland Acinar Cells. IUBMB Life 2005; 57:591-5. [PMID: 16118117 DOI: 10.1080/15216540500215598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Leptin, a pleiotropic cytokine that regulates food intake and metabolic and endocrine responses, has emerged recently as an important regulator of mucosal inflammatory responses to bacterial infection. In this study, we report that in sublingual salivary gland acinar cells leptin plays a role in the suppression of up-regulation in endothelin-1 (ET-1), induced by the LPS of a periodontopathic bacterium P. gingivalis. We show that P. gingivalisLPS detrimental effect on salivary mucin synthesis, associated with up-regulation (3.9-fold) in ET-1 generation and the enhancement (3.2-fold) in endothelin-converting enzyme-1 (ECE-1) activity, was subject to a dose-dependent suppression by leptin. The impedance by leptin of the LPS inhibitory effect on mucin synthesis was blocked by wortmannin, an inhibitor of PI3K, as well as by ERK inhibitor, PD98059. However, while the blockade of ERK led also to amplification in the impedance by leptin of the LPS-induced expression of ECE-1 and ET-1, the effect was not observed in the presence of wortmannin. The findings are the first to demonstrate that leptin counters the pathological consequences of P. gingivalisinfection on the synthesis of salivary mucin through the involvement in signaling events of PI3K and ERK pathways. We also show that the ERK cascade represents a critical signaling target for leptin in the LPS-induced up-regulation in ET-1.
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Affiliation(s)
- Bronislaw L Slomiany
- Research Center, University of Medicine and Dentistry of New Jersey, Newark 07103-2400, USA.
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Almon RR, Dubois DC, Jin JY, Jusko WJ. Temporal profiling of the transcriptional basis for the development of corticosteroid-induced insulin resistance in rat muscle. J Endocrinol 2005; 184:219-32. [PMID: 15642798 PMCID: PMC2574435 DOI: 10.1677/joe.1.05953] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Elevated systemic levels of glucocorticoids are causally related to peripheral insulin resistance. The pharmacological use of synthetic glucocorticoids (corticosteroids) often results in insulin resistance/type II diabetes. Skeletal muscle is responsible for close to 80% of the insulin-induced systemic disposal of glucose and is a major target for glucocorticoid-induced insulin resistance. We used Affymetrix gene chips to profile the dynamic changes in mRNA expression in rat skeletal muscle in response to a single bolus dose of the synthetic glucocorticoid methyl-prednisolone. Temporal expression profiles (analyzed on individual chips) were obtained from tissues of 48 drug-treated animals encompassing 16 time points over 72 h following drug administration along with four vehicle-treated controls. Data mining identified 653 regulated probe sets out of 8799 present on the chip. Of these 653 probe sets we identified 29, which represented 22 gene transcripts, that were associated with the development of insulin resistance. These 29 probe sets were regulated in three fundamental temporal patterns. 16 probe sets coding for 12 different genes had a profile of enhanced expression. 10 probe sets coding for eight different genes showed decreased expression and three probe sets coding for two genes showed biphasic temporal signatures. These transcripts were grouped into four general functional categories: signal transduction, transcription regulation, carbohydrate/fat metabolism, and regulation of blood flow to the muscle. The results demonstrate the polygenic nature of transcriptional changes associated with insulin resistance that can provide a temporal scaffolding for translational and post-translational data as they become available.
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Affiliation(s)
- Richard R Almon
- Department of Biological Sciences, State University of New York at Buffalo, Buffalo, NY 14260, USA.
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Albertini M, Clement MG, Hussain SNA. Role of endothelin ETA receptors in sepsis-induced mortality, vascular leakage, and tissue injury in rats. Eur J Pharmacol 2003; 474:129-35. [PMID: 12909204 DOI: 10.1016/s0014-2999(03)02037-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The role of endothelin ETA receptors in sepsis-induced mortality and edema formation was evaluated with a selective antagonist ABT-627 [2-(4-methoxyphenyl)-4-(1,3-benzodioxol-5-yl)-1-(N,N-di(n-butyl)amino carbonylmethyl)-pyrrolidine-3-carboxylic acid]. Sprague-Dawley rats received saline (control group), Escherichia coli endotoxin (10 mg/kg, sepsis group) or infusion of ABT-627 prior and immediately after saline and endotoxin injection. Mortality, edema formation (wet/dry ratios), and multiple tissue injury (indicated by serum concentrations of creatinine, urea, bilirubin, creatine kinase, lactate dehydrogenase, and aspartate aminotransferase) were monitored within 5 h. Endotoxin injection elicited 64% mortality, significantly augmented edema formation in liver, heart, lung, and kidney, and raised serum levels of tissue injury markers. Pretreatment with ABT-627 completely reversed endotoxin-induced mortality, significantly attenuated wet/dry ratios of the heart, liver, and kidney, but not lungs, and reduced serum levels of creatine kinase, creatinine, aspartate aminotransferase, and lactate dehydrogenase, but not that of urea and bilirubin. These results suggest that endothelin ETA receptors play a significant role in promoting mortality, edema formation (except in the lungs), and tissue injury in animals with severe sepsis.
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Affiliation(s)
- Mariangela Albertini
- Dipartimento di Patologia Animale, Igiene e Sanità Pubblica Veterinaria, Sezione di Biochimica e Fisiologia, Università degli Studi di Milano, Italy
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Albertini M, Borromeo V, Mazzola S, Ciminaghi B, Clement MG. Effects of endothelin-1 (ET-1) and thrombin antagonism on cardiovascular and respiratory dysfunctions during endotoxic shock in pig. Prostaglandins Leukot Essent Fatty Acids 2002; 67:445-51. [PMID: 12468266 DOI: 10.1054/plef.2002.0455] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
We evaluated the endothelin-1 (ET-1) and thrombin involvement in cardiovascular and respiratory dysfunction during endotoxic shock in 18 anaesthetized, mechanically ventilated pigs, divided into three groups. Group 1 was pre-treated only with lipopolysaccharide (LPS), group 2 was treated with lepirudin, a thrombin inhibitor, group 3 was pre-treated with bosentan, a dual inhibitor of ET-1 receptors. Results show that LPS caused systemic hypotension, pulmonary biphasic hypertension, increase in lung resistances (R(L)) and decrease in compliance (C(L)). Lepirudin partially reduced the LPS-dependent pulmonary hypertension, without affecting the changes in C(L) and R(L). On the contrary, bosentan completely abolished the pulmonary hypertension and the changes inC(L) and R(L), and worsened the LPS-dependent systemic hypotension. Our results show that ET-1 is largely responsible for pulmonary derangement due to endotoxic shock; at bronchial level, the ET-1 release seems due only to LPS, while, at pulmonary vascular level, it results also from LPS-dependent thrombin activation.
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Affiliation(s)
- M Albertini
- Dipartimento di Patologia animale, Igiene e Sanità pubblica Veterinaria, Sez. di Biochimica e Fisiologia, Università degli Studi di Milano, Milano, Italy
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Luyt CE, Lepailleur-Enouf D, Gaultier CJ, Valdenaire O, Steg G, Michel JB. Involvement of the Endothelin System in Experimental Critical Hind Limb Ischemia. Mol Med 2000. [DOI: 10.1007/bf03401829] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Filep JG. Role for endogenous endothelin in the regulation of plasma volume and albumin escape during endotoxin shock in conscious rats. Br J Pharmacol 2000; 129:975-83. [PMID: 10696098 PMCID: PMC1571901 DOI: 10.1038/sj.bjp.0703114] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
To explore the role of endogenous endothelin (ET) in the regulation of vascular functions, we studied the effects endothelin receptor blockade on blood pressure, plasma volume and albumin escape during endotoxin shock in conscious, chronically catheterized rats. Red blood cell volume and plasma volume were determined by using chromium-51-tagged erythrocytes and iodine-125-labelled albumin, respectively. Intravenous injection of lipopolysaccharide (LPS, 10 mg kg(-1)) resulted in hypotension, haemoconcentration, and increased total-body albumin escape, which is reflected by a 30% reduction in plasma volume. Plasma ET-1 concentrations increased 2.1 fold and 5.4 fold at 30 and 120 min post-LPS, respectively. LPS-induced losses in plasma volume and albumin escape were significantly attenuated by pretreatment of animals with the dual ET(A)/ET(B) receptor antagonist bosentan (17.4 micromol kg(-1), i.v. 15 min prior to LPS) or the ET(A) receptor antagonist FR 139317 (3.8 micromol kg(-1), i.v.) during both the immediate and delayed phases of endotoxin shock. The inhibitory actions of bosentan and FR 139317 were similar. Both antagonists augmented the hypotensive action of LPS. Administration of bosentan or FR 139317 70 min after injection of LPS also attenuated further losses in plasma volume and increases in total body and organ albumin escape rates with the exception of the lung and kidney. These results indicate a role for endogenous endothelin in mediating losses in plasma volume and albumin escape elicited by LPS predominantly through activation of ET(A) receptors, and suggest that by attenuating these events, ET(A) or dual ET(A)/ET(B) receptor blockers may be useful agents in the therapy of septic shock.
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Affiliation(s)
- J G Filep
- Research Center, Maisonneuve-Rosemont Hospital, University of Montréal, 5415 Boulevard de l'Assomption, Montréal, Québec, HIT 2M4, Canada
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