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Hector R Wong,
Natalie Cvijanovich,
Geoffrey L Allen,
Richard Lin,
Nick Anas,
Keith Meyer,
Robert J Freishtat,
Marie Monaco,
Kelli Odoms,
Bhuvaneswari Sakthivel, Thomas P Shanley
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ABSTRACT: To advance our biological understanding of pediatric septic shock, we measured the genome-level expression profiles of critically ill children representing the systemic inflammatory response syndrome (SIRS), sepsis, and septic shock spectrum.
Prospective observational study involving microarray-based bioinformatics.
Multiple pediatric intensive care units in the United States.
Children <or=10 years of age: 18 normal controls, 22 meeting criteria for SIRS, 32 meeting criteria for sepsis, and 67 meeting criteria for septic shock on day 1. The available day 3 samples included 20 patients still meeting sepsis criteria, 39 patients still meeting septic shock criteria, and 24 patients meeting the exclusive day 3 category, SIRS resolved.
None other than standard care.
Longitudinal analyses were focused on gene expression relative to control samples and patients having paired day 1 and day 3 samples. The longitudinal analysis focused on up-regulated genes revealed common patterns of up-regulated gene expression, primarily corresponding to inflammation and innate immunity, across all patient groups on day 1. These patterns of up-regulated gene expression persisted on day 3 in patients with septic shock, but not to the same degree in the other patient classes. The longitudinal analysis focused on down-regulated genes demonstrated gene repression corresponding to adaptive immunity-specific signaling pathways and was most prominent in patients with septic shock on days 1 and 3. Gene network analyses based on direct comparisons across the SIRS, sepsis, and septic shock spectrum, and all available patients in the database, demonstrated unique repression of gene networks in patients with septic shock corresponding to major histocompatibility complex antigen presentation. Finally, analyses focused on repression of genes corresponding to zinc-related biology demonstrated that this pattern of gene repression is unique to patients with septic shock.
Although some common patterns of gene expression exist across the pediatric SIRS, sepsis, and septic shock spectrum, septic shock is particularly characterized by repression of genes corresponding to adaptive immunity and zinc-related biology.
Critical care medicine 04/2009; 37(5):1558-66. · 6.37 Impact Factor
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ABSTRACT: Mortality in children with sepsis is most often related to diminished cardiac output with cardiovascular collapse, resulting in impaired oxygen delivery and ultimately, end-organ failure. Although cardiovascular "collapse" is commonly observed in individuals with septic shock, the hemodynamic causes of this differ greatly. In children, intrinsic myocardial dysfunction is most commonly present, while the systemic vascular resistance is typically high. This pattern is distinct from adults with sepsis where the principle hemodynamic profile shows elevated cardiac output, but substantially reduced systemic vascular resistance. Various studies support the concept that myocardial dysfunction, as occurs in pediatric septic patients, is due to intrinsic abnormalities in cardiomyocyte function and is not related to hypoperfusion as a result of low systemic vascular resistance. Importantly, when examined more closely, data from adults with septic shock also reveal that intrinsic myocardial dysfunction may play a larger role then previously appreciated. As a result, cardiovascular support, especially in pediatric sepsis requires a treatment strategy directed at the underlying mechanism(s) responsible for this dysfunction. Thus, it is imperative to gain a better understanding of the myocardial derangements that occur during sepsis in order to identify targets that will ultimately influence the management of children with septic shock and favorably alter the associated mortality. We hypothesize that key signaling pathways that control myocardial calcium flux, regulated to key kinases and phosphatases, influence myocyte contractility in sepsis. Thus, we review the data relevant to the sepsis-induced intracellular alterations in calcium flux in the cardiomyocyte, with an emphasis on changes in the phosphorylation state of the contractile proteins regulated by the balance between kinases and phosphatases. We believe therapies modulating the activity of these key proteins may provide an improvement in calcium handling and myocardial contractility and alter the clinical outcomes in sepsis.
Shock (Augusta, Ga.) 01/2009; · 2.87 Impact Factor
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Hector Wong,
Natalie Cvijanovich,
Richard Lin,
Geoffrey Allen,
Neal Thomas,
Douglas Willson,
Robert Freishtat,
Nick Anas,
Keith Meyer,
Paul Checchia,
Marie Monaco,
Kelli Odom, Thomas Shanley
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ABSTRACT: Abstract
Background
Septic shock is a heterogeneous syndrome within which probably exist several biological subclasses. Discovery and identification of septic shock subclasses could provide the foundation for the design of more specifically targeted therapies. Herein we tested the hypothesis that pediatric septic shock subclasses can be discovered through genome-wide expression profiling.
Methods
Genome-wide expression profiling was conducted using whole blood-derived RNA from 98 children with septic shock, followed by a series of bioinformatic approaches targeted at subclass discovery and characterization.
Results
Three putative subclasses (subclasses A, B, and C) were initially identified based on an empiric, discovery-oriented expression filter and unsupervised hierarchical clustering. Statistical comparison of the three putative subclasses (analysis of variance, Bonferonni correction, P < 0.05) identified 6,934 differentially regulated genes. K-means clustering of these 6,934 genes generated 10 coordinately regulated gene clusters corresponding to multiple signaling and metabolic pathways, all of which were differentially regulated across the three subclasses. Leave one out cross-validation procedures indentified 100 genes having the strongest predictive values for subclass identification. Forty-four of these 100 genes corresponded to signaling pathways relevant to the adaptive immune system and glucocorticoid receptor signaling, the majority of which were repressed in subclass A patients. Subclass A patients were also characterized by repression of genes corresponding to zinc-related biology. Phenotypic analyses revealed that subclass A patients were younger, had a higher illness severity, and a higher mortality rate than patients in subclasses B and C.
Conclusion
Genome-wide expression profiling can identify pediatric septic shock subclasses having clinically relevant phenotypes.
BMC Medicine. 01/2009;
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ABSTRACT: To examine a large cohort of children treated with extracorporeal life support (ECLS) for severe respiratory failure to investigate the hypothesis that patients with an immune compromise condition (ICC) would have reduced survival to hospital discharge compared with patients without this classification.
Retrospective cohort study.
Extracorporeal Life Support Organization (ELSO) data registry.
All nonneonatal pediatric patients receiving ECLS for respiratory failure.
None.
As of February 4, 2004, the ELSO registry contained 2,879 pediatric patients between 1 month and 19 yrs of age who were treated with ECLS for respiratory failure. Overall, 183 patients had at least one International Classification of Diseases (Ninth Revision) or Current Procedural Terminology code associated with an ICC; ICC status was associated with lower hospital survival (31 vs. 57 %; p < .001). Six ICC subgroups were also examined: immune deficiency, leukemia-lymphoma, cancer, opportunistic infection, solid organ transplant, and bone marrow transplant. Each ICC subgroup was also associated with reduced hospital survival, varying from a high of 34.6% (solid organ transplants) to a low of 0% (bone marrow transplant). In a multivariate logistic regression model that controlled for factors reported to be associated with survival and other respiratory interventions (high-frequency ventilation, inhaled nitric oxide, and surfactant), the presence of an ICC remained associated with reduced hospital survival (odds ratio 0.20-0.45; p < .001). In this multivariate model, an unexpected strong association between inhaled nitric oxide therapy and lower ECLS survival was observed (odds ratio 0.49-0.80; p < .001).
In this cohort of pediatric patients receiving ECLS for respiratory failure, survival to hospital discharge was reduced for each ICC subgroup examined and was approximately one in three for the overall group. Further study of the association of lower survival rates for patients who received inhaled nitric oxide prior to ECLS is needed.
Pediatric Critical Care Medicine 05/2008; 9(4):380-5. · 3.13 Impact Factor
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Vania Hinkovska-Galcheva,
Andrea Clark,
Susan VanWay,
Ji-Biao Huang,
Miki Hiraoka,
Akira Abe,
Michael Borofsky,
Robin G Kunkel, Thomas Shanley,
James A Shayman,
Frederick Lanni,
Howard R Petty,
Laurence A Boxer
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ABSTRACT: Ceramide-1-phosphate (C1P) is a novel bioactive sphingolipid formed by the phosphorylation of ceramide catalyzed by ceramide kinase (CERK). In this study, we evaluated the mechanism by which increased C1P during phagocytosis enhances phagocytosis and phagolysosome formation in COS-1 cells expressing hCERK. Stable transfectants of COS-1 cells expressing FcgammaRIIA or both FcgammaRIIA/hCERK expression vectors were created. Cell fractionation studies demonstrated that hCERK and the transient receptor potential channel (TRPC-1) were enriched in caveolae fractions. Our data establish that both CERK and TRPC-1 localize to the caveolar microdomains during phagocytosis and that CERK also colocalizes with EIgG in FcgammaRIIA/hCERK-bearing COS-1 cells. Using high-speed fluorescence microscopy, FcgammaRIIA/hCERK transfected cells displayed Ca2+ sparks around the phagosome. In contrast, cells expressing FcgammaRIIA under identical conditions displayed little periphagosomal Ca2+ signaling. The enhanced Ca2+ signals were accompanied by enhanced phagolysosome formation. However, the addition of pharmacological reagents that inhibit store-operated channels (SOCs) reduced the phagocytic index and phagolysosomal fusion in hCERK transfected cells. The higher Ca2+ signal observed in hCERK transfected cells as well as the fact that CERK colocalized with EIgG during phagocytosis support our hypothesis that Ca2+ signaling is an important factor for increasing phagocytosis and is regulated by CERK in a manner that involves SOCs/TRPCs.
The Journal of Lipid Research 04/2008; 49(3):531-42. · 5.56 Impact Factor
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ABSTRACT: Granulocyte-macrophage-colony-stimulating factor (GM-CSF) plays a critical role in innate immunity by stimulating the differentiation of tissue macrophages via the transcription factor PU.1. Previous studies showed that GMCSF-deficient(GM-CSF-/-) mice had susceptibility to and impaired clearance of group B streptococcal bacteria by macrophages. For these studies, we hypothesized that GM-CSF-/- mice have increased susceptibility to peritonitis caused by immune dysfunction of peritoneal macrophages. We examined the role of peritoneal macrophages in pathogen clearance, cytokine responses, and survival in a murine cecal ligation and puncture (CLP) model of peritonitis/sepsis. Surprisingly, CLP minimally affected survival in GM-CSF-/- mice while markedly reducing survival in wild-type mice. This was not explained by differences in the composition of microbial flora, rates of bacterial peritonitis, or sepsis, all of which were similar in GM-CSF-/- and wild-type mice. However, survival correlated with peritoneal and serum TNF-alpha and IL-6 levels that were significantly lower in GM-CSF-/- than in control mice. After peritoneal LPS instillation, GM-CSF-/- mice also had improved survival and reduced TNF-alpha and IL-6 responses. In vitro studies demonstrated reduced secretion of TNF-alpha and IL-6 by peritoneal macrophages isolated from sham GM-CSF-/- mice as compared with macrophages from sham control mice. Peritoneal instillation of GM-CSF-/-/PU.1+ macrophages, but not GM-CSF-/-/PU.1+ macrophages into GM-CSF-/- mice conferred susceptibility to death after CLP or peritoneal LPS exposure. These results demonstrate that GM-CSFY/PU.1-dependent peritoneal macrophage responses are a critical determinant of survival after experimentally induced peritonitis/sepsis or exposure to LPS and have implications for therapies to treat such infections.
Shock (Augusta, Ga.) 03/2008; 30(4):434-42. · 2.87 Impact Factor
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Thomas P. Shanley
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ABSTRACT: Cellular responses to external stimuli proceed through multiply complex signal transduction networks. The manner by which signals are propagated from the cell's surface to the nuclei is, in large part, dependent on the phosphorylation of signaling proteins mediated by kinases. As in most biological systems, this process of kinase-mediated phosphorylation is balanced by the presence of a dephosphorylating system comprised of a number of families of phosphatases. The purpose of this review is to describe the various members of the main classes of phosphatases and to examine their role in regulating signal transduction pathways relevant to critical illness. Because recent work has provided key insight into the role of kinase-mediated signaling pathways, such as the mitogen-activated protein kinase and inhibitor of nuclear factor-kappaB kinase pathways, in inflammatory states, emphasis has been placed on the regulation of these events. It is hoped that deriving novel insight into the regulatory phosphatases will allow a greater understanding of inflammatory cell signaling events and potentially identify novel sites for therapeutic intervention in the future.
Critical care medicine 02/2002; 30(1 Supp):S80-S88. · 6.37 Impact Factor
