RESUMEN
BACKGROUND: Enterococci, and especially multiresistant Enterococcus faecium, are increasingly found colonizing hospitalized patients. This increased prevalence of colonization is not only associated with an increased prevalence of infections caused by enterococci, but also by infections with other nosocomial pathogens. In this study we investigated the causality of this observed relationship, by determining the influence of intestinal colonization with E. faecium on pulmonary defense against Pseudomonas aeruginosa. METHODOLOGY/PRINCIPAL FINDINGS: Three groups of mice were tested; 2 groups of mice were pre-treated with vancomycin, of which one group was subsequently treated by oral gavage of vancomycin-resistant E. faecium (VRE). The third group did not receive any pre-treatment. P. aeruginosa pneumonia was induced in all mice. Vancomycin treatment resulted in intestinal gram-negative bacterial overgrowth and VRE treatment resulted in colonization throughout the intestines. All 3 groups of mice were able to clear P. aeruginosa from the lungs and circulation, with comparable lung cytokine responses and lung damage. Mice treated with vancomycin without VRE colonization displayed modestly increased plasma levels of TNF-alpha and IL-10. CONCLUSION: Overgrowth of E. faecium and/or gram-negative bacteria does not impact importantly on pulmonary defense against P. aeruginosa pneumonia.
Asunto(s)
Enterococcus faecium/fisiología , Intestinos/microbiología , Pulmón/microbiología , Pseudomonas aeruginosa/patogenicidad , Animales , Enterococcus faecium/crecimiento & desarrollo , Femenino , Ratones , Ratones Endogámicos C57BL , Neumonía Bacteriana/inmunologíaRESUMEN
The increasing incidence of infections with multi-drug resistant Enterococcus faecium necessitates studies to increase knowledge on the pathogenesis of these infections. In this study, the contribution of peritoneal macrophages during E. faecium peritonitis was investigated. In an ex vivo setting, peritoneal macrophages harvested from C57BL/6 mice were responsive to, and able to phagocytose and kill, E. faecium. In vivo, peritoneal macrophages were depleted by intraperitoneal injection of clodronate-encapsulated liposomes, prior to inducing E. faecium peritonitis. Depletion of resident peritoneal macrophages caused a clear delay in peritoneal clearance of E. faecium with increased systemic dissemination. Mice depleted of peritoneal macrophages were able to recruit macrophages and neutrophils to the peritoneal cavity after infection, comparable to control mice. Furthermore, increased levels of peritoneal cytokines and chemokines were found in mice depleted of peritoneal macrophages. This study indicates that peritoneal macrophages are important in the early containment of E. faecium peritonitis and for the regulation of the inflammatory response.
Asunto(s)
Citocinas/inmunología , Enterococcus faecium/inmunología , Infecciones por Bacterias Grampositivas/inmunología , Macrófagos Peritoneales/inmunología , Peritonitis/inmunología , Animales , Ácido Clodrónico/farmacología , Citocinas/metabolismo , Femenino , Infecciones por Bacterias Grampositivas/complicaciones , Liposomas , Macrófagos Peritoneales/efectos de los fármacos , Macrófagos Peritoneales/microbiología , Ratones , Ratones Endogámicos C57BL , Peritonitis/microbiología , Fagocitosis/efectos de los fármacos , Fagocitosis/inmunologíaRESUMEN
PURPOSE: Multiresistant and vancomycin resistant Enterococcus faecium (VRE) can cause serious infections in hospitalized patients with various co-morbid diseases. We investigated the course of VRE peritonitis after cecal ligation and puncture (CLP)-induced sepsis and compared this to sham operated mice. METHODS: Mice were subjected to CLP or sham surgery. Forty-eight hours thereafter four groups were created by subjecting mice to peritoneal injection of either VRE or saline. RESULTS: Mice infected with VRE after CLP were severely impaired in eliminating VRE from the peritoneal cavity and distant body sites. These mice failed to mount an early inflammatory response at the primary site of VRE infection. VRE superinfection did not influence CLP-induced organ damage or polymicrobial bacterial loads. CONCLUSIONS: Sublethal polymicrobial sepsis greatly facilitates infection and dissemination of VRE. VRE does not influence the course of CLP-induced sepsis.
Asunto(s)
Ciego/cirugía , Quimiocina CCL2/inmunología , Enterococcus faecium , Infecciones por Bacterias Grampositivas/complicaciones , Infecciones por Bacterias Grampositivas/inmunología , Interferón gamma/inmunología , Interleucinas/inmunología , Ligadura/efectos adversos , Ligadura/métodos , Peritonitis/inmunología , Peritonitis/cirugía , Punciones/efectos adversos , Punciones/métodos , Sepsis/etiología , Sepsis/inmunología , Sepsis/microbiología , Factor de Necrosis Tumoral alfa/inmunología , Animales , Ensayo de Inmunoadsorción Enzimática , Femenino , Ratones , Ratas , Ratas Sprague-DawleyRESUMEN
Enterococcus faecium is an emerging pathogen that causes infections in hospitalized patients with various co-morbid diseases. These underlying diseases are often associated with an acute-phase response that renders patients vulnerable to nosocomial infections. To study the influence of the acute-phase response induced by sterile tissue injury on host defence against E. faecium, mice were injected subcutaneously with either turpentine or casein 1 day before intraperitoneal infection with E. faecium. Control mice were subcutaneously injected with saline or sodium bicarbonate, respectively. Turpentine and casein induced an acute-phase response as reflected by increases in the plasma concentrations of interleukin-6, serum amyloid P and C3. A pre-existent acute-phase response in mice was associated with a strongly reduced capacity to clear E. faecium, resulting in prolonged bacteraemia for several days. The inflammatory response to E. faecium was impaired in mice with an acute-phase response, as shown by reduced capacity to mount a neutrophilic leucocytosis in peripheral blood and by decreased local cytokine concentrations. These data indicate that the acute-phase response impairs host defence against E. faecium, suggesting that this condition may contribute to the increased vulnerability of critically ill patients to enterococcal infections.
Asunto(s)
Reacción de Fase Aguda/inmunología , Enterococcus faecium/inmunología , Infecciones por Bacterias Grampositivas/inmunología , Neutrófilos/inmunología , Peritonitis/inmunología , Reacción de Fase Aguda/inducido químicamente , Reacción de Fase Aguda/metabolismo , Reacción de Fase Aguda/microbiología , Animales , Caseínas/farmacología , Quelantes/farmacología , Complemento C3/agonistas , Complemento C3/inmunología , Complemento C3/metabolismo , Citocinas/efectos de los fármacos , Citocinas/inmunología , Citocinas/metabolismo , Enterococcus faecium/efectos de los fármacos , Femenino , Infecciones por Bacterias Grampositivas/metabolismo , Infecciones por Bacterias Grampositivas/microbiología , Interleucina-6/agonistas , Interleucina-6/sangre , Irritantes/farmacología , Ratones , Ratones Endogámicos C57BL , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Peritonitis/metabolismo , Peritonitis/microbiología , Componente Amiloide P Sérico/agonistas , Componente Amiloide P Sérico/inmunología , Componente Amiloide P Sérico/metabolismo , Trementina/farmacologíaRESUMEN
A progressive increase in infections with multiresistant Enterococcus faecium has been reported, especially in cancer patients and neutropenic patients. Despite its increasing importance as a nosocomial pathogen, knowledge of the pathogenesis of E. faecium infections is highly limited. In this study, we investigated the role of neutrophils during peritonitis with subsequent bacteremia caused by E. faecium. Therefore, we depleted neutrophils by intraperitoneal injections of monoclonal antibody RB6-8C5. Mice were followed for 5 days, and the enterococcal outgrowth and inflammatory response were compared between neutropenic mice and immunoglobulin G-injected control mice. Neutropenic mice demonstrated a severe delay in enterococcal clearance from all cultured organs (peritoneal fluid, blood, and lung and liver tissue). In particular, neutropenic mice remained bacteremic for up to 3 days, whereas all nonneutropenic mice had cleared the bacteria from circulation by 2 days. Furthermore, neutropenic mice displayed elevated peritoneal cytokine and chemokine levels 1 day after the infection and attracted fewer macrophages into the peritoneal cavity. In the circulation, a prolonged elevation of tumor necrosis factor alpha, interleukin-6, and the acute-phase proteins serum amyloid A and complement 3 were measured in neutropenic mice. In conclusion, attraction of neutrophils to the primary site of E. faecium infection is important for a rapid clearance of this bacterium, thereby attenuating a systemic inflammatory response.
Asunto(s)
Enterococcus faecium/inmunología , Neutrófilos/inmunología , Animales , Líquido Ascítico/química , Líquido Ascítico/microbiología , Bacteriemia/inmunología , Bacteriemia/microbiología , Sangre/microbiología , Recuento de Colonia Microbiana , Citocinas/análisis , Citocinas/sangre , Femenino , Infecciones por Bacterias Grampositivas/inmunología , Humanos , Recuento de Leucocitos , Procedimientos de Reducción del Leucocitos , Hígado/microbiología , Pulmón/microbiología , Ratones , Peritonitis/inmunología , Peritonitis/microbiologíaRESUMEN
Low dose prednisolone was shown to be beneficial in the treatment of the Acute respiratory distress syndrome (ARDS) and septic shock. One corticosteroid-induced effect, postulated to mediate corticosteroid-induced anti-inflammatory effects, is decreased expression of adhesion molecules on endothelial cells, thereby preventing leukocyte recruitment at inflammatory sites. The current study aimed to investigate the effect of increasing doses of prednisolone on the release of soluble adhesion molecules in healthy volunteers challenged with endotoxin. Therefore, 32 healthy, male volunteers received prednisolone orally at doses of 0mg, 3mg, 10mg or 30 mg at 2h before injection of endotoxin prepared from Escherichia coli (4 ng/kg) and levels of soluble E-selectin (sE-selectin), soluble VCAM-1 (sVCAM-1) and soluble ICAM-1 (sICAM-1) were measured. Levels of all markers were increased after induction of endotoxemia. Levels of sE-selectin were inhibited by a dose of 3mg prednisolone and levels of sVCAM-1 were decreased after a dose of 10mg. Maximal inhibition of both sE-selectin and sVCAM-1 levels was achieved by the highest dose of prednisolone 30 mg. Remarkably, prednisolone 3mg potentiated endotoxin-induced sVCAM-1 release. Levels of sICAM-1 were not affected by prednisolone. Together, the data suggest that prednisolone differentially and dose-dependently influences the release of soluble endothelial adhesion molecules during human endotoxemia.
Asunto(s)
Antiinflamatorios/administración & dosificación , Moléculas de Adhesión Celular/metabolismo , Endotoxemia/tratamiento farmacológico , Escherichia coli/inmunología , Prednisolona/administración & dosificación , Administración Oral , Adulto , Moléculas de Adhesión Celular/genética , Moléculas de Adhesión Celular/inmunología , Movimiento Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Selectina E/sangre , Selectina E/inmunología , Endotoxemia/inmunología , Humanos , Inyecciones Intravenosas , Molécula 1 de Adhesión Intercelular/sangre , Molécula 1 de Adhesión Intercelular/inmunología , Recuento de Leucocitos , Lipopolisacáridos/administración & dosificación , Activación de Linfocitos/efectos de los fármacos , Masculino , Molécula 1 de Adhesión Celular Vascular/sangre , Molécula 1 de Adhesión Celular Vascular/inmunologíaRESUMEN
Beta2-adrenergic receptors are expressed on different cell types in the lung, including respiratory epithelial cells, smooth muscle cells, and macrophages. The aim of the current study was to determine the role of beta-adrenergic receptors in the regulation of lung inflammation induced by instillation via the airways of lipopolysaccharide (LPS) (a constituent of the gram-negative bacterial cell wall) or lipoteichoic acid (LTA) (a component of the gram-positive bacterial cell wall). Mice inhaled the beta-adrenergic antagonist propranolol or saline 30 minutes before and 3 hours after intranasal LPS or LTA administration. LPS and LTA induced a profound inflammatory response in the lungs as reflected by an influx of neutrophils and the release of proinflammatory cytokines and chemokines into bronchoalveolar lavage fluid (BALF). Propranolol inhalation resulted in enhanced LPS-induced lung inflammation, which was reflected by a stronger secretion of TNF-alpha, IL-6, and monocyte chemoattractant protein-1 into BALF and by enhanced coagulation activation (thrombin-antithrombin complexes). In LTA-induced lung inflammation, propranolol did not influence cytokine release but potentiated activation of coagulation. Propranolol did not alter neutrophil recruitment in either model. This study suggests that beta-adrenergic receptors, which are widely expressed in the lungs, serve as negative regulators of pulmonary cytokine release and coagulation induced by LPS and less so during LTA-induced pulmonary inflammation.
Asunto(s)
Coagulación Sanguínea , Citocinas/antagonistas & inhibidores , Pulmón/inmunología , Neumonía Bacteriana/inmunología , Receptores Adrenérgicos beta 2/fisiología , Administración por Inhalación , Agonistas de Receptores Adrenérgicos beta 2 , Antagonistas de Receptores Adrenérgicos beta 2 , Antagonistas Adrenérgicos beta/administración & dosificación , Antagonistas Adrenérgicos beta/farmacología , Animales , Coagulación Sanguínea/efectos de los fármacos , Líquido del Lavado Bronquioalveolar , Citocinas/metabolismo , Relación Dosis-Respuesta a Droga , Femenino , Lipopolisacáridos/inmunología , Lipopolisacáridos/toxicidad , Pulmón/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Neutrófilos/efectos de los fármacos , Propranolol/administración & dosificación , Propranolol/farmacología , Ácidos Teicoicos/inmunología , Ácidos Teicoicos/toxicidadRESUMEN
The incidence of infections with Enterococcus faecium is increasing worldwide. TLRs have been implicated in the recognition of pathogens and the initiation of an adequate innate immune response. We here sought to determine the roles of MyD88, the common adaptor protein involved in TLR signaling, TLR2, TLR4, and CD14 in host defense against E. faecium peritonitis. MyD88 knockout (KO) mice demonstrated an impaired early response to E. faecium peritonitis, as reflected by higher bacterial loads in peritoneal fluid and liver accompanied by a markedly attenuated neutrophil influx into the abdominal cavity. In vitro, not only MyD88 KO macrophages but also TLR2 KO and CD14 KO macrophages displayed a reduced responsiveness to E. faecium. In accordance, transfection of TLR2 rendered human embryonic kidney 293 cells responsive to E. faecium, which was enhanced by cotransfection of CD14. TLR2 KO mice showed higher bacterial loads in peritoneal fluid after in vivo infection with E. faecium and a diminished influx of neutrophils, whereas CD14 KO mice had an unaltered host response. E. faecium phagocytosis and killing were not affected by MyD88, TLR2, or CD14 deficiency. TLR4 did not play a role in the immune response to E. faecium in vitro or in vivo. These data suggest that MyD88 contributes to the effective clearance of E. faecium during peritonitis at least in part via TLR2 and by facilitating neutrophil recruitment to the site of the infection.
Asunto(s)
Enterococcus faecium/inmunología , Factor 88 de Diferenciación Mieloide/inmunología , Factor 88 de Diferenciación Mieloide/metabolismo , Peritonitis/inmunología , Transducción de Señal/inmunología , Receptor Toll-Like 2/inmunología , Receptor Toll-Like 2/metabolismo , Animales , Línea Celular , Modelos Animales de Enfermedad , Femenino , Humanos , Macrófagos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factor 88 de Diferenciación Mieloide/deficiencia , Factor 88 de Diferenciación Mieloide/genética , Peritonitis/genética , Peritonitis/metabolismo , Fagocitos/inmunología , Factores de TiempoRESUMEN
Corticosteroids are widely used for the suppression of cell-mediated cytoxicity. This process is mediated by natural killer cells and cytotoxic T lymphocytes, and their activation can be monitored by levels of the chemokines CXCL9 and CXCL10, the degranulation product granzymes A and B, and by levels of secretory phospholipase A2. The current study aimed to determine the effects of increasing doses of prednisolone on the release of these mediators in healthy humans exposed to LPS. Therefore, 32 healthy men received prednisolone orally at doses of 0, 3, 10, or 30 mg (n = 8 per group) at 2 h before intravenous injection of Escherichia coil LPS (4 ng/kg). Prednisolone dose-dependently attenuated the LPS-induced rises in the plasma concentrations of the chemokines CXCL9 and CXCL10, as well as of granzymes A and B levels. CXCL10 and granzyme B release were most sensitive to prednisolone, with a significant inhibition already achieved at the lowest prednisolone dose (3 mg). The levels of secretory phospholipase A2 were increased after LPS administration but were not significantly affected by prednisolone. This study demonstrates that prednisolone differentially inhibits the systemic release of mediators involved in cell-mediated cytotoxicity in humans in vivo.
Asunto(s)
Citotoxicidad Inmunológica/efectos de los fármacos , Endotoxemia/inmunología , Prednisolona/farmacología , Linfocitos T/inmunología , Administración Oral , Adulto , Quimiocina CXCL10/sangre , Quimiocina CXCL9/sangre , Citotoxicidad Inmunológica/inmunología , Relación Dosis-Respuesta a Droga , Endotoxemia/sangre , Granzimas/sangre , Humanos , Inyecciones Intravenosas , Células Asesinas Naturales/citología , Células Asesinas Naturales/inmunología , Lipopolisacáridos/administración & dosificación , Lipopolisacáridos/farmacología , Masculino , Prednisolona/administración & dosificación , Linfocitos T/citología , Linfocitos T Citotóxicos/citología , Linfocitos T Citotóxicos/inmunologíaRESUMEN
OBJECTIVE: Sepsis intervention studies need better patient stratification methods, and one way to realize this is the introduction of stable biomarkers. A set of recently developed novel biomarkers, based upon precursor-fragments of short-lived hormones, was previously shown to be increased during sepsis. However, it is not known whether these biomarkers are influenced by sepsis intervention strategies. Therefore we investigated the markers in a model of human endotoxemia intervened by increasing doses of prednisolone. DESIGN AND SETTING: Prospective, open-label study in a specialized clinical research unit of a university hospital. SUBJECTS: Thirty-two healthy male volunteers. INTERVENTIONS: Subjects received prednisolone orally at doses of 0, 3, 10 or 30 mg (n=8 per group) at 2 h before intravenous injection of Escherichia coli lipopolysaccharide (LPS) (4 ng/kg). Blood samples were drawn during 24 h after LPS injection. MEASUREMENTS AND RESULTS: LPS injection caused an increase in levels of midregional pro-adrenomedullin (MR-proADM), midregional pro-atrial natriuretic peptide (MR-proANP), C-terminal pro-arginine-vasopressin (CT-proAVP) and procalcitonin (PCT). Prednisolone caused a dose dependent inhibition of MR-proADM, MR-proANP and CT-proAVP levels. CONCLUSIONS: These results show that a set of novel, highly stable sepsis biomarkers was increased during human endotoxemia and was dose-dependently inhibited by corticosteroid pre-treatment.
Asunto(s)
Endotoxemia/sangre , Endotoxemia/tratamiento farmacológico , Hormonas Peptídicas/sangre , Prednisolona/farmacología , Precursores de Proteínas/sangre , Administración Oral , Adrenomedulina/sangre , Adulto , Arginina Vasopresina/sangre , Factor Natriurético Atrial/sangre , Biomarcadores/sangre , Calcitonina/sangre , Péptido Relacionado con Gen de Calcitonina , Relación Dosis-Respuesta a Droga , Endotoxemia/inducido químicamente , Humanos , Mediadores de Inflamación/sangre , Inyecciones Intravenosas , Lipopolisacáridos/farmacología , Masculino , Prednisolona/sangre , Prednisolona/farmacocinética , Estudios Prospectivos , Sepsis/sangre , Sepsis/tratamiento farmacológico , Índice de Severidad de la EnfermedadRESUMEN
The cholinergic nervous system can inhibit the release of proinflammatory cytokines such as TNF-alpha from LPS-stimulated macrophages. Acetylcholine, the principal neurotransmitter of the vagus nerve, is the key mediator of this so-called cholinergic anti-inflammatory pathway, specifically interacting with alpha7 cholinergic receptors expressed by macrophages and other cell types to inhibit TNF-alpha production. The aim of the current study was to determine the capacity of the selective alpha7 cholinergic receptor agonist 3-(2,4-dimethoxybenzylidene) anabaseine (GTS-21), administered locally into the airways, to inhibit LPS-induced inflammatory responses in the mouse lung in vivo. GTS-21 dose-dependently inhibited LPS-induced TNF-alpha release by MH-S mouse alveolar macrophages in vitro. Intranasal inoculation with GTS-21 also dose-dependently inhibited TNF-alpha release into the lung compartment after intrapulmonary delivery of LPS in mice in vivo, whereas IL-6 concentrations were not affected. However, GTS-21 did not influence the influx of neutrophils into bronchoalveolar lavage fluid elicited by LPS and increased the concentrations of the neutrophil-attracting chemokines cytokine-induced neutrophil chemoattractant and macrophage inflammatory protein 2. These data indicate that local administration of GTS-21 inhibits TNF-alpha release in the lung during LPS-induced inflammation.
Asunto(s)
Lipopolisacáridos/farmacología , Pulmón/efectos de los fármacos , Agonistas Nicotínicos/farmacología , Receptores Nicotínicos/fisiología , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Compuestos de Bencilideno/farmacología , Línea Celular , Relación Dosis-Respuesta a Droga , Femenino , Pulmón/citología , Pulmón/metabolismo , Linfocitos/citología , Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Macrófagos/citología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Macrófagos Alveolares/citología , Macrófagos Alveolares/efectos de los fármacos , Macrófagos Alveolares/metabolismo , Ratones , Ratones Endogámicos C57BL , Neutrófilos/citología , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Piridinas/farmacología , Receptor Nicotínico de Acetilcolina alfa 7RESUMEN
The cholinergic nervous system controls inflammation by inhibiting the release of proinflammatory cytokines such as tumor necrosis factor (TNF) alpha from lipopolysaccharide (LPS)-stimulated macrophages. The key endogenous mediator of this so-called cholinergic anti-inflammatory pathway is acetylcholine, the principal neurotransmitter of the vagus nerve, which specifically interacts with alpha7 cholinergic receptors expressed by macrophages and other cell types to inhibit TNF-alpha production. We here investigated the capacity of the selective alpha7 cholinergic receptor agonist 3-(2,4-dimethoxybenzylidene) anabaseine (GTS-21) to inhibit LPS-induced inflammatory responses in mice in vivo. To this end, mice received an intraperitoneal injection of LPS (from Escherichia coli, 200 microg) preceded by GTS-21 (4 mg/kg) or vehicle. GTS-21 strongly inhibited LPS-induced TNF-alpha release into the peritoneal cavity and the circulation. In addition, GTS-21 attenuated the influx of neutrophils into peritoneal fluid upon administration of LPS. This inhibitory effect on neutrophil recruitment by GTS-21 was independent of its effect on TNF-alpha release, considering that etanercept, a potent TNF-alpha-blocking protein containing the extracellular domain of the p75 TNF-alpha receptor, did not influence LPS-induced neutrophil influx either in the presence or in the absence of GTS-21 treatment. GTS-21 did not reduce the local secretion of macrophage inflammatory protein 2 and keratinocyte-derived cytokine, suggesting that altered concentrations of these neutrophil-attracting chemokines did not contribute to GTS-21-induced inhibition of neutrophil migration. These data identify a novel anti-inflammatory effect of chemical alpha7 cholinergic receptor stimulation that is independent from its capacity to inhibit TNF-alpha production.
Asunto(s)
Inhibición de Migración Celular , Lipopolisacáridos/antagonistas & inhibidores , Infiltración Neutrófila/inmunología , Receptores Nicotínicos/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Animales , Compuestos de Bencilideno/farmacología , Citocinas/metabolismo , Femenino , Lipopolisacáridos/farmacología , Ratones , Ratones Endogámicos C57BL , Agonistas Nicotínicos/farmacología , Piridinas/farmacología , Receptores Nicotínicos/fisiología , Receptor Nicotínico de Acetilcolina alfa 7RESUMEN
The effects of steroids on the outcome of sepsis are dose dependent. Low doses appear to be beneficial, but high doses do not improve outcome for reasons that are insufficiently understood. The effects of steroids on systemic inflammation as a function of dose have not previously been studied in humans. To determine the effects of increasing doses of prednisolone on inflammation and coagulation in humans exposed to LPS, 32 healthy males received prednisolone orally at doses of 0, 3, 10, or 30 mg (n = 8 per group) at 2 h before i.v. injection of Escherichia coli LPS (4 ng/kg). Prednisolone dose-dependently inhibited the LPS-induced release of cytokines (TNF-alpha and IL-6) and chemokines (IL-8 and MCP-1), while enhancing the release of the anti-inflammatory cytokine IL-10. Prednisolone attenuated neutrophil activation (plasma elastase levels) and endothelial cell activation (von Willebrand factor). Most remarkably, prednisolone did not inhibit LPS-induced coagulation activation, measured by plasma concentrations of thrombin-antithrombin complexes, prothrombin fragment F1+2, and soluble tissue factor. In addition, activation of the fibrinolytic pathway (tissue-type plasminogen activator and plasmin-alpha(2)-antiplasmin complexes) was dose-dependently enhanced by prednisolone. These data indicate that prednisolone dose-dependently and differentially influences the systemic activation of different host response pathways during human endotoxemia.
Asunto(s)
Coagulación Sanguínea/efectos de los fármacos , Endotoxemia/tratamiento farmacológico , Endotoxemia/patología , Inflamación/tratamiento farmacológico , Prednisolona/administración & dosificación , Adulto , Biomarcadores/sangre , Quimiocinas/sangre , Citocinas/sangre , Citocinas/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células Endoteliales/efectos de los fármacos , Escherichia coli , Fibrinólisis/efectos de los fármacos , Humanos , Lipopolisacáridos/administración & dosificación , Masculino , Activación Neutrófila/efectos de los fármacos , Prednisolona/farmacologíaRESUMEN
OBJECTIVE: Catecholamines have anti-inflammatory and anticoagulant properties. Dobutamine is a synthetic catecholamine frequently used in patients with septic myocardial dysfunction. The objective was to determine whether a continuous infusion of dobutamine exerts immunomodulatory effects in healthy volunteers challenged with endotoxin. DESIGN: Prospective, open-label study. SETTING: Clinical research unit of a university hospital. PARTICIPANTS: Sixteen male healthy volunteers. INTERVENTIONS: Volunteers received a constant infusion with dobutamine (10 microg.kg.min, n = 8) or physiologic saline (n = 8). All participants were challenged with a bolus injection of endotoxin prepared from Escherichia coli (4 ng/kg). Dobutamine infusion was commenced 1 hr before endotoxin challenge and was continued until 3 hrs thereafter. MEASUREMENTS AND MAIN RESULTS: Dobutamine infusion was associated with an increase in mean arterial blood pressure (peak 122 +/- 5 mm Hg) and heart rate (peak 84 +/- 4 beats/min, both p < .05 vs. saline). Endotoxin injection induced the systemic release of cytokines (tumor necrosis factor-alpha, interleukins-6, -8, and -10) and secretory phospholipase A2, endothelial cell activation (increase in the plasma levels of soluble E-selectin and von Willebrand factor), activation of coagulation (increased plasma levels of soluble tissue factor, F1 + 2 prothrombin fragment, and thrombin-antithrombin complexes), and activation with subsequent inhibition of fibrinolysis (increased plasma concentrations of tissue-type plasminogen activator, plasminogen activator inhibitor type I, and plasmin-alpha2-antiplasmin complexes). None of these responses were influenced by dobutamine. CONCLUSIONS: Dobutamine, infused in a clinically relevant dose, does not influence inflammatory and coagulant pathways during human endotoxemia.