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Gene expression analysis in polytrauma patients comparing sepsis vs. non-sepsis

ABSTRACT: BACKGROUND: Despite best supportive intensive care, the development of severe sepsis and septic shock after trauma is still associated with a high mortality rate in intensive care units (ICU). Incomplete knowledge of the pathophysiological and biochemical mechanisms that lead to perturbations of the host system is a major cause for this clinical entity. This lack of knowledge is mirrored in a delay in both diagnosis of sepsis and stratification of patients at risk. The current diagnostic and classification methods do not provide an early and reliable evidence for the development of sepsis and consequently lead to uncertainty in the classification and a delay in the initiation of an adequate therapy. Here, we present a prospective study performed with a well-defined patient cohort suffering from severe multiple trauma (n=85), in which we aimed to uncover the biological reasons why patients with multiple trauma can have dramatically different outcomes after suffering similar traumatic insults. METHODS: We used peripheral whole blood obtained with the PaxGene system at the time of admission to the ICU, i.e., 12 hours after trauma, for transcriptome analysis and monitored clinically the sequence of events from the admission to the ICU, to the very onset of sepsis and finally to the full development of multiple organ dysfunction syndrome (MODS). Study protocols and standard operating procedures (SOPs) regarding ethics, patient recruitment, logistics in sample acquisition and storage, microarray experiments, data analysis and data management have been developed and provided for a high feasibility and reproducibility of the investigations. FINDINGS: The transcriptome analysis from peripheral blood revealed a strong host response upon severe injury and demonstrated the suitability of whole blood in the PaxGene system as a surrogate marker in clinical gene expression studies. It was evident that patients who developed sepsis in the course of the disease (3-5 days after admission) showed an imbalance in the TH1/TH2 response towards a pronounced TH2 response, soon after trauma. The imbalanced TH1/TH2 shift along with inactivation of T cells, neutrophils, monocytes and macrophages might be critical factors for the initiation of a septic program seen in these patients 12 hours after trauma. INTERPRETATION: First, in this study, we provide protocols for logistics and infrastructure that can be applied generally to successfully integrate gene expression analysis studies in a clinical routine and demonstrate that by following these protocols, dedicated and reproducible results can be obtained. Second, we showed that peripheral whole blood is a suitable surrogate marker for the host response as it contains lots of “information” and is easily accessible. Third, we identified mechanisms involved in the perturbations of the immune system that lead to sepsis. Keywords: Prospective study

ORGANISM(S): Homo sapiens

PROVIDER: GSE12624 | GEO | 2010/12/22

SECONDARY ACCESSION(S): PRJNA113091

REPOSITORIES: GEO

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Project description:BACKGROUND: Despite best supportive intensive care, the development of severe sepsis and septic shock after trauma is still associated with a high mortality rate in intensive care units (ICU). Incomplete knowledge of the pathophysiological and biochemical mechanisms that lead to perturbations of the host system is a major cause for this clinical entity. This lack of knowledge is mirrored in a delay in both diagnosis of sepsis and stratification of patients at risk. The current diagnostic and classification methods do not provide an early and reliable evidence for the development of sepsis and consequently lead to uncertainty in the classification and a delay in the initiation of an adequate therapy. Here, we present a prospective study performed with a well-defined patient cohort suffering from severe multiple trauma (n=85), in which we aimed to uncover the biological reasons why patients with multiple trauma can have dramatically different outcomes after suffering similar traumatic insults. METHODS: We used peripheral whole blood obtained with the PaxGene system at the time of admission to the ICU, i.e., 12 hours after trauma, for transcriptome analysis and monitored clinically the sequence of events from the admission to the ICU, to the very onset of sepsis and finally to the full development of multiple organ dysfunction syndrome (MODS). Study protocols and standard operating procedures (SOPs) regarding ethics, patient recruitment, logistics in sample acquisition and storage, microarray experiments, data analysis and data management have been developed and provided for a high feasibility and reproducibility of the investigations. FINDINGS: The transcriptome analysis from peripheral blood revealed a strong host response upon severe injury and demonstrated the suitability of whole blood in the PaxGene system as a surrogate marker in clinical gene expression studies. It was evident that patients who developed sepsis in the course of the disease (3-5 days after admission) showed an imbalance in the TH1/TH2 response towards a pronounced TH2 response, soon after trauma. The imbalanced TH1/TH2 shift along with inactivation of T cells, neutrophils, monocytes and macrophages might be critical factors for the initiation of a septic program seen in these patients 12 hours after trauma. INTERPRETATION: First, in this study, we provide protocols for logistics and infrastructure that can be applied generally to successfully integrate gene expression analysis studies in a clinical routine and demonstrate that by following these protocols, dedicated and reproducible results can be obtained. Second, we showed that peripheral whole blood is a suitable surrogate marker for the host response as it contains lots of “information” and is easily accessible. Third, we identified mechanisms involved in the perturbations of the immune system that lead to sepsis. Keywords: Prospective study 159 consecutive traumatized patients were included in the study upon admission to the intensive care unit (ICU), fulfilling all of the following inclusion criteria: severe injuries to at least two body regions or three major fractures, between 18 and 65 years of age, an estimated Injury Severity Score (ISS) of ?15 points after thorough assessment of injuries, <12 hours between the occurrence of the accident and the time of admission to the ICU, and at least greater than 3 days of survival. None of the patients underwent neuro- or cardiac surgery. We excluded patients with severe intracranial head injuries, coagulation abnormalities known at the day of admission to the ICU, acute renal failure, liver failure, malignant disease, or hemofiltration in the patient`s history. The Patients were divided into two groups depending on their posttraumatic course: Patients not complicatd by sepsis (Group: N) and Patients complicated by sepsis (Group: S). Using the CodeLink UniSet Human 10 K Bioarrays (GE Healthcare, Freiburg, Germany), we searched for early differences in the transcriptome of these two groups. Only whole blood samples drawn upon admission to the ICU were used for this investigation. Microarray results were validated by quantification of mRNA by TaqMan® technology. Each patient sample was hybridized in duplicate or triplicate on microarrays (label-extract technical replicate). A total of 72 arrays (36 group N, 36 group S) were subjected to microarray quality analysis. Of these, 2 arrays (0 group N, 2 group S) were excluded from the data set due to quality reasons and a final set of 70 arrays (36 group N and 34 group S) were subjected to microarray analysis. Since the eliminated 2 arrays belonged to patients with three replicates, they were treated as two replicates in the further analysis. The arrays were designated N_xx_yy_z or S_xx_yy_z, with x for the patient-ID (1,2,3,4..) and z for the technical replicate number (1,2 or 3).

Project description:The study was aimed to identify mechanisms linked to complicated courses after severe trauma by a systems biology approach. In severe trauma, overwhelming systemic inflammation can result in adverse events and the development of complications, including sepsis. In a prospective study, RNA samples from circulating leukocytes from patients with multiple injury (injury severity score â¥ 17) were analyzed for dynamic changes in gene expression over a period of 21 days by whole genome screening. Based on their clinical presentation, patients were divided into two subgroups: patients with secondary sepsis after trauma (n=5) and patients with systemic inflammation without infection (n=5). Expression cluster were defined by correlating gene expression data with clinical outcome parameters. Using unsupervised clustering, patients with systemic inflammation only and patients with sepsis showed a distinct expression pattern and the discrimination of clinical presentation was reflected by clustering of the samples. Explorative gene set analysis revealed robust upregulation of genes related to âhemoglobin metabolism/oxygen transportâ and âpathogenic E.coli infectionâ. 10 patients with multi-system trauma (ISS â¥ 17 points) admitted to the Division of Trauma Surgery at the University Hospital Zurich were included. Whole blood from trauma patients was collected within the first 6 h after trauma (day 0) and on days 1, 2, 3, 5, 7, 10, 14, and 21. Total cellular RNA from circulating leukocytes was isolated using PaxGene Blood RNA Kit (PreAnalytix) for transcriptome profiling. RNA from blood of trauma patients was extracted and subjected to microarray analysis for comparison of longitudinal transcriptomic responses of patients. RNA samples of circulating leukocytes covering time points directly after admission (D0) and on the consecutive days (D1-D21) were subject to multifactorial microarray data analysis: Differences in dynamics of transcripts were assessed by contrasting time- and individual-resolved changes for sepsis and systemic inflammation without infection.

Project description:Background: Systemic inflammation is a whole body reaction that can have an infection-positive (i.e. sepsis) or infection-negative origin. It is important to distinguish between septic and non-septic presentations early and reliably, because this has significant therapeutic implications for critically ill patients. We hypothesized that a molecular classifier based on a small number of RNAs expressed in peripheral blood could be discovered that would: 1) determine which patients with systemic inflammation had sepsis; 2) be robust across independent patient cohorts; 3) be insensitive to disease severity; and 4) provide diagnostic utility. The overall goal of this study was to identify and validate such a molecular classifier. Methods and Findings: We conducted an observational, non-interventional study of adult patients recruited from tertiary intensive care units (ICU). Biomarker discovery was conducted with an Australian cohort (n = 105) consisting of sepsis patients and post -surgical patients with infection-negative systemic inflammation. Using this cohort, a four-gene classifier consisting of a combination of CEACAM4, LAMP1, PLA2G7 and PLAC8 RNA biomarkers was identified. This classifier, designated SeptiCyteÂ® Lab, was externally validated using RT-qPCR and receiver operating characteristic (ROC) curve analysis in five cohorts (n = 345) from the Netherlands. Cohort 1 (n=59) consisted of unambiguous septic cases and infection-negative systemic inflammation controls; SeptiCyteÂ® Lab gave an area under curve (AUC) of 0.96 (95% CI: 0.91-1.00). ROC analysis of a more heterogeneous group of patients (Cohorts 2-5; 249 patients after excluding 37 patients with infection likelihood possible) gave an AUC of 0.89 (95% CI: 0.85-0.93). Disease severity, as measured by Sequential Organ Failure Assessment (SOFA) score or the Acute Physiology and Chronic Health Evaluation (APACHE) IV score, was not a significant confounding variable. The diagnostic utility o f SeptiCyteÂ® Lab was evaluated by comparison to various clinical and laboratory parameters that would be available to a clinician within 24 hours of ICU admission. SeptiCyteÂ® Lab was significantly better at differentiating sepsis from infection-negative systemic inflammation than all tested parameters, both singly and in various logistic combinations. SeptiCyteÂ® Lab more than halved the diagnostic error rate compared to PCT in all tested cohorts or cohort combinations. Conclusions: SeptiCyteÂ® Lab is a rapid molecular assay that may be clinically useful in the management of ICU patients with systemic inflammation. SIRS and Sepsis ICU patients, admission samples Retrospective, mutli-site sutdy using retrospective physician adjudication as a comparator

Project description:BACKGROUND: Patients encountering severe trauma are at risk of developing sepsis syndrome and subsequent multiple organ failure. This is often associated with fatal outcome despite survival of the initial injury. We undertook a prospective cohort study of trauma patients to examine the role of tumor necrosis factor alpha (TNF-alpha) in the pathogenesis of sepsis syndrome and mortality. METHODS: 159 severely traumatized patients from a single centre were included. Serial blood samples were analyzed for serum concentrations of TNF-alpha and lymphotoxin alpha (LT-alpha). We genotyped nine polymorphisms in the TNF gene and tested for an association with sepsis syndrome and outcome. Genetic associations were validated in an external replication sample (n=76). We examined the peripheral blood transcriptome in n=28 patients by whole genome-based profiling and validated the results. RESULTS: Carriage of the TNF rs1800629 A allele was associated with higher TNF-alpha serum concentrations on the first day after trauma and during follow up (two-sided p=5.0x10-5), with development of sepsis syndrome (OR 7.14, two-sided p=1.2x10-6; external validation sample (n=76): OR 3.3, one-sided p=0.03), and with fatal outcome (OR 7.65, two-sided p=1.9x10-6). Carriage of the TNF rs1800629 A allele was associated with differential expression of genes representing stronger pro-inflammatory and apoptotic responses as compared to carriage of the wild type allele. CONCLUSIONS: Common TNF gene variants are associated with sepsis syndrome and death after severe injury. These findings are strongly supported by functional data and may be important for developing preemptive anti-inflammatory interventions in carriers of the risk-associated allele. Keywords: Disease state analysis 159 consecutive traumatized patients were included in the study upon admission to the intensive care unit (ICU), fulfilling all of the following inclusion criteria: severe injuries of at least two body regions or three major fractures, between 18 and 65 years of age, an estimated Injury Severity Score (ISS)21 of ≥12 points after thorough assessment of injuries, <12 hours between the occurrence of the accident and time of admission to the ICU, and at least more than 3 days of survival. None of the patients underwent neuro- or cardiac surgery. We excluded patients with severe intracranial head injuries, coagulation abnormalities known at the day of admission to the ICU, acute renal failure, liver failure, malignant disease, or hemofiltration in the patient`s history. All patients were genotyped for nine polymorphisms in the TNF gene and tested for an association with sepsis syndrome and outcome. The genotyping results revealed significant association for the carriage of a TNF rs1800629 A allele with higher TNF-alpha serum concentrations on the first day after trauma and during follow up, with development of sepsis syndrome (OR 7.14), and with fatal outcome (OR 7.65). To obtain more insight into the biological mechanisms underlying the findings in the genotyping study, we searched for differences in the peripheral blood transcriptome from patients with and without the TNF rs1800629 A variant. From 28 patients, we examined the transcpriptome from peripheral blood using the CodeLink UniSet Human 10 K Bioarrays (GE Healthcare, Freiburg, Germany). Only whole blood samples drawn upon admission to the ICU were used for this investigation. Microarray results were validated by quantification of mRNA by TaqMan® technology. The patients were dichotomized into two groups: group A) 16 patients without the TNF rs1800629 A variant (WT1-16) and group B) 12 patients carrying the TNF rs1800629 A variant (MUT1-12). Each patient sample was hybridized in duplicate on microarrays (label-extract technical replicate). A total of 75 arrays (42 group A, 33 group B) were subjected to microarray quality analysis. Of these, 17 arrays (12 group A, 5 group B) were excluded from the data set due to quality reasons and a final set of 58 arrays (30 group A and 28 group B) was subjected to microarray analysis. The arrays were designated WTx.y or MUTx.y with WT for patients with and MUT for patients without the TNF rs1800629 A variant, with x for the patient-ID (1,2,3,4..) and y for the technical replicate number (1,2 or 3).

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Gene expression analysis in polytrauma patients comparing sepsis vs. non-sepsis

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