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Query: UMLS:C0243026 (sepsis)
 52,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Selenium therapy in patients with severe sepsis improves clinical outcome and has been associated with increased activity of the selenoprotein glutathione peroxidase. However, the mechanism of the observed beneficial effects remains unclear. We determined the effect of selenium treatment on the monocyte adhesion molecule L-selectin and L-selectin-related monocyte functions in vitro and transferred our findings to an in vivo mouse model. Monocytes were purified, cultured, and incubated in the presence or absence of supplemented selenium and metalloproteinase (MP) inhibitors for up to 16 h. Expression of L-selectin was unaffected after 2 and 6 h but decreased after 16 h of incubation in the presence of selenium. Soluble L-selectin (sL-selectin) in the supernatant was determined by ELISA. A 2.3-fold increase as a result of shedding of L-selectin was observed after 16 h of selenium treatment. Addition of the MP inhibitors GM6001, TNF-alpha-converting enzyme inhibitor 2, or GW280264X strongly reduced selenium-induced L-selectin shedding, indicating a MP-dependent mechanism. The functional consequences of L-selectin shedding were examined in a flow chamber model. Selenium-treated monocytes showed significantly decreased rolling and adhesion to the L-selectin ligand Sialyl-Lewis(a) under conditions of venous shear stress (0.5 dyne/cm(2)). Selenium treatment of C57BL6 mice led to increased serum levels of sL-selectin, underscoring the in vivo relevance of our findings. We describe a selenium-induced down-regulation of L-selectin on monocytes as a consequence of MP-dependent shedding of this membrane-anchored adhesion molecule. The impairment of monocyte adhesion by selenium supplementation may represent an important, underlying mechanism for the modulation of inflammatory reactions in patients with severe sepsis.
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PMID:Selenium supplementation induces metalloproteinase-dependent L-selectin shedding from monocytes. 1830 78

LPSs getting access to the circulation of mammalian organisms cause typical systemic inflammatory reactions with symptoms characteristic for acute sepsis. One possibility to attenuate LPS effects is to expose a host to a challenge with low LPS doses, which results in the establishment of "endotoxin tolerance" (ET). Because the microcirculation is of particular importance in LPS action, it seemed of interest to analyze leukocyte-endothelial interactions in the mesentery and liver once endotoxin tolerance has been established and are challenged with LPS. The mesenteric and hepatic microcirculation was investigated by intravital microscopy. After induction of ET LPS, shock was induced by i.v. injection of LPS, and microcirculation of the mesentery and liver was examined. Endotoxin tolerance resulted in reduced ex vivo TNF-alpha synthesis of whole blood. In vivo LPS caused no increase of body temperature. In sinusoids, LPS challenge increased adherence of leukocytes in naive rats, which was almost completely prevented by ET induction. In contrast, in postsinusoidal venules, leukocyte adherence was more intense after ET induction and subsequent to LPS application. Similarly, in postcapillary mesenteric venules, increased adherence of leukocytes after LPS challenge in the ET group was observed. After LPS injection, the endothelial barrier was more disturbed in the nontolerant group when compared with the ET group. Soluble L-selectin and intercellular adhesion molecule were elevated in both ET and untreated rats. Endotoxin tolerance influences leukocyte-endothelial interaction differentially depending on organ and vessel area.
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PMID:Microcirculatory alterations of hepatic and mesenteric microcirculation in endotoxin tolerance. 1838 90

Fractalkine (FTK) is a unique member of the CX3C chemokine family by acting through the CX3CR1 receptor. Membrane-bound FTK acts like an adhesion molecule, whereas soluble FTK (sFTK) acts as a classic chemokine ligand. Whether this chemokine plays a role in sepsis is still not clear. Using a mouse model of cecal ligation and puncture (CLP)-induced sepsis, we found that FTK levels were elevated in plasma 24 h after CLP. Reverse transcription-polymerase chain reaction results showed that FTK messenger RNA levels were upregulated, whereas CX3CR1 messenger RNA levels were downregulated in lungs after CLP procedure. To study the role of FTK in lung injury during sepsis, we injected exogenous sFTK into the mice before the CLP procedure. We found that plasma FTK levels were further elevated by sFTK. Mice that were injected with FTK had a lower myeloperoxidase activity in lungs compared with the CLP group. Furthermore, macrophage inflammatory protein 2, IL-1beta, and IL-6 levels in lungs were reduced after the injection of FTK. Treatment with sFTK also attenuated lung morphological changes in histological sections. To find out whether sFTK had an effect on leukocyte rolling and adherence, intravital microscope was used. Results showed that sFTK significantly attenuated leukocyte adhesion but had little effect on leukocyte rolling in mesenteric microcirculation. Taken together, our findings suggest that FTK may be a novel chemokine that modulates neutrophil infiltration and chemokine and cytokine production during sepsis.
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PMID:Administration of exogenous fractalkine, a CX3C chemokine, is capable of modulating inflammatory response in cecal ligation and puncture-induced sepsis. 1849 8

This study investigated the effects of fish oil on adhesion molecule expression and tissue myeloperoxidase (MPO) activity in hypercholesterolemic mice with sepsis. There were one control and two experimental groups in this study. The control group (C) was fed a regular chow diet for 7 weeks, while hypercholesterolemia in the experimental group was induced by feeding a high-fat diet (20%, w/w) with cholesterol (2%, w/w) for 4 weeks. Then the experimental group was divided into two subgroups with identical nutrient distributions except that one subgroup was fed soybean oil (SO), while part of the soybean oil was replaced by fish oil (FO) in the other one for 3 weeks. After feeding the diets for 7 weeks, sepsis was induced in all three groups by cecal and ligation and puncture (CLP), and mice were sacrificed at 0, 6 or 24 h after CLP, respectively. The results showed that the FO group had a higher intracellular interferon-gamma/interleukin-4 ratio and lower tumor necrosis factor-alpha and monocyte chemoattractant protein-1 concentrations in peritoneal lavage fluid at 6 h after CLP than those in the C and SO groups. Lymphocyte CD11a/CD18 expressions were higher at 0 and 6 h and neutrophil CD11b/CD18 were higher at 6 h in the SO group than in the FO and C groups. The SO group had higher plasma intercellular adhesion molecule (ICAM)-1 levels than C group at 0 and 6 h, whereas no difference in ICAM-1 concentrations were observed between the C and FO groups at 0 h after CLP. Hypercholesterolemia resulted in higher tissue MPO activities. There were no differences in MPO activities in various organs between the two experimental groups. These results suggest that hypercholesterolemic mice fed FO did not exhibit immunosuppression when complicated with sepsis. FO administration reduced adhesion molecule expressions and inflammatory-related mediators at the site of injury at an early but not a late stage of sepsis. However, compared with the SO group, the influences of FO on MPO activities in various organs were not obvious in hypercholesterolemic mice with sepsis.
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PMID:Effects of dietary fish oil supplementation on cellular adhesion molecule expression and tissue myeloperoxidase activity in hypercholesterolemic mice with sepsis. 1860 12

Sepsis is a multifactorial, and often fatal, disorder typically characterized by widespread inflammation and immune activation with resultant endothelial activation. In the present study, we postulated that the adipokine adiponectin serves as a critical modulator of survival and endothelial activation in sepsis. To this aim, we evaluated both loss-of-function (adiponectin gene-deficient mice) and subsequent gain-of-function (recombinant adiponectin reconstitution) strategies in two well-established inflammatory models, cecal ligation perforation (CLP) and thioglyocollate-induced peritonitis. Adipoq(-/-) mice, subjected to CLP, exhibited a profound ( approximately 8-fold) reduction in survival compared with their wild-type Adipoq(+/+) littermates after 48 h. Furthermore, compared with wild-type controls, thioglycollate challenge resulted in a markedly greater influx of peritoneal neutrophils in Adipoq(-/-) mice accompanied by an excess production of key chemoattractant cytokines (IL-12p70, TNFalpha, MCP-1, and IL-6) and upregulation of aortic endothelial adhesion molecule VCAM-1 and ICAM-1 expressions. Importantly, all of these effects were blunted by recombinant total adiponectin administration given 3 days prior to thioglycollate challenge. The protective effects of adiponectin were ascribed largely to higher-order adiponectin oligomers, since administration of recombinant C39A trimeric adiponectin did not attenuate endothelial adhesion molecule expression in thioglycollate-challenged Adipoq(-/-) mice. These data suggest a critical role of adiponectin as a modulator of survival and endothelial inflammation in experimental sepsis and a potential mechanistic link between adiposity and increased sepsis.
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PMID:Adiponectin deficiency promotes endothelial activation and profoundly exacerbates sepsis-related mortality. 1917 45

Sex is increasingly recognized as a major factor in the outcome of patients who have trauma and sepsis. Moreover, sex steroids influence chemokine/adhesion molecule expression and neutrophil accumulation. Heat shock proteins, heat shock factor 1, and peroxisome proliferator-activated receptor [gamma] coactivator 1 are regulated by the estrogen receptors and consequently contribute to organ protection after trauma-hemorrhage. Additionally, sex steroids regulate inflammatory cytokines, leading to increased morbidity and mortality. This article deals with trauma-hemorrhage and examines the following: 1) the evidence for sex differences; 2) the mechanisms by which sex hormones affect organ protection; 3) the tissue-specific effect of sex hormone receptors; and 4) the effect of genomic and nongenomic (i.e. membrane-initiated steroid signaling) pathways of sex hormones after trauma. The available information indicates that sex steroids modulate cardiovascular responses after trauma. Thus, alteration or modulation of the prevailing hormone milieu at the time of injury seems to be a novel therapeutic option for improving outcome after injury
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PMID:The role of estrogen and receptor agonists in maintaining organ function after trauma-hemorrhage. 1866 49

Leukocyte adhesion contributes to perfusion abnormalities and tissue damage during trauma, shock or overwhelming inflammation. This study was performed to determine whether the lipoxygenase inhibitor phenidone and derivatives decrease the expression of adhesion molecules on tumor necrosis factor-alpha (TNF-alpha) stimulated endothelial cells and attenuate leukocyte-endothelial interactions under flow in vitro. TNF-alpha stimulated human umbilical venous endothelial cells (HUVECs) were incubated with phenidone, 4-methyl-phenidone, 4-4-dimethyl-phenidone, 5-methyl-phenidone, 5-phenyl-phenidone, and 5-methyl-1,(2,5-di-chloro-phenyl)-3-pyrazolidone. We tested the inhibition of adhesion molecule expression at different inhibitor concentrations before, during, and after the stimulation of HUVECs. The inhibition of endothelial cell expression on HUVECs was measured by flow cytometry. Rolling and firm adhesion of leukocytes to pretreated endothelium was examined in a parallel plate flow chamber. Phenidone inhibited the expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and endothelial-leukocyte adhesion molecule-1 on HUVECs when added prior to HUVEC stimulation. The inhibitory effect of phenidone was still observed when added simultaneously, but not when added after HUVEC stimulation. 4-4-dimethyl-phenidone and 5-phenyl-phenidone inhibited the expression of adhesion molecules more effectively than phenidone. The attenuation of leukocyte rolling under flow conditions was also significantly more effective with 4-4-dimethyl-phenidone than with phenidone. Lipoxygenase inhibitors might be of therapeutically interest for the treatment of overwhelming systemic inflammation during shock, trauma, and sepsis.
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PMID:Activity of the lipoxygenase inhibitor 1-phenyl-3-pyrazolidinone (phenidone) and derivatives on the inhibition of adhesion molecule expression on human umbilical vascular endothelial cells. 1970 38

Severe septic illness is often associated with cerebral manifestations such was disturbed consciousness and delirium. Little was known about its effect on the CNS. This is the first study in children that has assessed the direct mediators of brain inflammation and injury with sepsis. The serum and CSF concentrations of soluble intracellular adhesion molecule-1 (sICAM-1) (marker of endothelium-leukocyte interaction), nitric oxide (NO) and lipid peroxide (LPO) (markers for lipid peroxidation) and S-100B protein (marker of astrocytes activation and injury), were measured in 40 children with sepsis of whom 40% had moderate to severe septic encephalopathy. Serum from 25 normal children was used for comparison. Serum values of sICAM-1, NO, LPO and S100B were elevated in patients compared to controls. The greater elevation of the CSF:serum albumin ratio suggests loss of blood-brain barrier integrity. After normalising for CSF:serum albumin ratio, we demonstrated a significant intrathecal synthesis of NO, LPO and S100B. Patients with encephalopathy had elevated serum and CSF levels of sICAM-1, NO, LPO and S100B compared to sepsis only. This study indicates that the brain is vulnerable in children with sepsis. It also suggests that coordinated interactions between immune system, vascular endothelial cells, CNS barriers, astrocytes and brain lipid peroxides, may contribute to septic encephalopathy.
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PMID:Septic encephalopathy: relationship to serum and cerebrospinal fluid levels of adhesion molecules, lipid peroxides and S-100B protein. 1980 34

The microcirculation is not merely a passive conduit for red cell transport, nutrient and gas exchange, but is instead a dynamic participant contributing to the multiple processes involved in the maintenance of metabolic homeostasis and optimal end-organ function. The microcirculation's angioarchitechture and surface properties influence conduit function and flow dynamics over a wide spectrum of conditions, accommodating many different mechanical, pathological or organ-specific responses. The endothelium itself plays a critical role as the interface between tissues and blood components, participating in the regulation of coagulation, inflammation, vascular tone, and permeability. The complex nitric oxide pathways affect vasomotor tone and influence vascular conduit caliber and distribution density, alter thrombotic propensity, and modify adhesion molecule expression. Nitric oxide pathways also interact with red blood cells and free hemoglobin moieties in normal and pathological conditions. Red blood cells themselves may affect flow dynamics. Altered rheology and compromised NO bioavailability from medical storage or disease states impede microcirculatory flow and adversely modulate vasodilation. The integration of the microcirculation as a system with respect to flow modulation is delicately balanced, and can be readily disrupted in disease states such as sepsis. This review will provide a description of these varied and intricate functions of the microvasculature.
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PMID:The dynamic regulation of microcirculatory conduit function: features relevant to transfusion medicine. 2058 Mar 15

The endothelium-derived relaxing factor that mediates the endothelium-dependent vasodilatation first observed in 1980 has been identified as nitric oxide (NO). In addition to the endothelium, NO is formed in other cells such as neuronal cells of the brain (where it mediates synoptic plasticity), peripheral nonadrenergic noncholinergic (NANC) nerves (where it acts as an atypical neurotransmitter relaxing vascular and nonvascular smooth muscle), and various specialized epithelial cells. Other cell types such as macrophages and smooth muscle cells can be induced with bacterial endotoxin and/or cytokines to synthesize large amounts of the radical. At low concentrations, NO is an inter- and intracellular messenger molecule whose target enzyme is the soluble isoform of guanylyl cyclase. At high concentrations, the NO radical has cytostatic effects on parasitic microorganisms and tumor cells. In the vascular system, endothelium-derived NO is a physiologically significant vasodilator and inhibitor of platelet aggregation and adhesion. NANC nerve-derived NO may also contribute to vasodilatation. In addition, NO can prevent leukocyte adhesion to the endothelium by interfering with the adhesion molecule CD11/CD18, and NO has been shown to inhibit the proliferation of vascular smooth muscle cells. In sepsis and during cytokine therapy, a different NOS is induced in the vascular wall (presumably in smooth muscle cells) where it synthesizes large amounts of NO that contribute to the massive vasodilatation and shock.
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PMID:Nitric oxide synthases in the cardiovascular system. 2124 48


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