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Patterns of gene expression in peripheral blood mononuclear cells and outcomes from patients with sepsis secondary to community acquired pneumonia.

ABSTRACT: Mechanisms governing the inflammatory response during sepsis have been shown to be complex, involving cross-talk between diverse signaling pathways. Current knowledge regarding the mechanisms underlying sepsis provides an incomplete picture of the syndrome, justifying additional efforts to understand this condition. Microarray-based expression profiling is a powerful approach for the investigation of complex clinical conditions such as sepsis. In this study, we investigate whole-genome expression profiles in mononuclear cells from survivors (n = 5) and non-survivors (n = 5) of sepsis. To circumvent the heterogeneity of septic patients, only patients admitted with sepsis caused by community-acquired pneumonia were included. Blood samples were collected at the time of sepsis diagnosis and seven days later to evaluate the role of biological processes or genes possibly involved in patient recovery. Principal Components Analysis (PCA) profiling discriminated between patients with early sepsis and healthy individuals. Genes with differential expression were grouped according to Gene Ontology, and most genes related to immune defense were up-regulated in septic patients. Additionally, PCA in the early stage was able to distinguish survivors from non-survivors. Differences in oxidative phosphorylation seem to be associated with clinical outcome because significant differences in the expression profile of genes related to mitochondrial electron transport chain (ETC) I-V were observed between survivors and non-survivors at the time of patient enrollment. Global gene expression profiles after seven days of sepsis progression seem to reproduce, to a certain extent, patterns collected at the time of diagnosis. Gene expression profiles comparing admission and follow-up samples differed between survivors and non-survivors, with decreased expression of genes related to immune functions in non-survivors. In conclusion, genes related to host defense and inflammatory response ontology were up-regulated during sepsis, consistent with the need for a host response to infection, and the sustainability of their expression in follow-up samples was associated with outcomes.

SUBMITTER: Severino P

PROVIDER: S-EPMC3965402 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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Patterns of gene expression in peripheral blood mononuclear cells and outcomes from patients with sepsis secondary to community acquired pneumonia.

Severino Patricia P Silva Eliézer E Baggio-Zappia Giovana Lotici GL Brunialti Milena Karina Coló MK Nucci Laura Alejandra LA Rigato Otelo O da Silva Ismael Dale Cotrim Guerreiro ID Machado Flávia Ribeiro FR Salomao Reinaldo R

PloS one 20140325 3

Mechanisms governing the inflammatory response during sepsis have been shown to be complex, involving cross-talk between diverse signaling pathways. Current knowledge regarding the mechanisms underlying sepsis provides an incomplete picture of the syndrome, justifying additional efforts to understand this condition. Microarray-based expression profiling is a powerful approach for the investigation of complex clinical conditions such as sepsis. In this study, we investigate whole-genome expressio ...[more]

PMID: 24667684

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Project description:Sepsis is defined as a systemic inflammatory response secondary to a proven or suspected infection. Mechanisms governing this inflammatory response have been shown to be complex and dynamic, involving cross-talking among diverse signaling pathways. However, current knowledge on mechanisms underlying sepsis is far from providing a complete picture of the syndrome, justifying additional efforts that might add to this scenario. Microarray-based expression profiling is a powerful approach for the investigation of complex clinical conditions such as sepsis: the analysis of gene transcription at the genome level potentially avoids results derived from biased assumptions. In this study we investigate whole-genome gene expression profiles of mononuclear cells from survivor and non-survivor septic patients. Blood samples were collected at the time of sepsis diagnosis and seven days later, allowing us to evaluate the role of biological processes or genes possibly involved in patient recovery. Aiming to circumvent, at least partially, the heterogeneity of septic patients we included only patients admitted with sepsis caused by community-acquired pneumonia. Global gene expression profiling allowed us to characterize early sepsis, as compared to healthy individuals. Our results corroborate literature reports on inflammation response in the early stages of sepsis but highlight great heterogeneity in gene expression during sepsis progress. Additionally, global gene expression in the early stage was also able to distinguish sepsis from septic shock and correlated with patient outcome. Differences in oxidative stress seem to be associated with clinical outcome, since significant differences in the expression profile of related genes were observed between survivors and non-survivors at the time of patient enrollment (early sepsis). However, our results substantiate current knowledge supporting that sepsis syndrome development is indeed multifaceted. Although the initial infection of enrolled patients was pneumonia, seven days later gene expression profiles seemed to be characteristic of each patient, common gene expression changes distinguishing survivors from non-survivors. This result could be associated with the underlying health status of each one of them, with complications due to sepsis itself as well as with distinct timing for response to treatment.

Project description:OBJECTIVES:Metabolic derangements in sepsis stem from mitochondrial injury and contribute significantly to organ failure and mortality; however, little is known about mitochondrial recovery in human sepsis. We sought to test markers of mitochondrial injury and recovery (mitochondrial biogenesis) noninvasively in peripheral blood mononuclear cells from patients with sepsis and correlate serial measurements with clinical outcomes. DESIGN:Prospective case-control study. SETTING:Academic Medical Center and Veterans Affairs Hospital. PATIENTS:Uninfected control patients (n = 20) and septic ICU patients (n = 37). INTERVENTIONS:Blood samples were collected once from control patients and serially with clinical data on days 1, 3, and 5 from septic patients. Gene products for HMOX1, NRF1, PPARGC1A, and TFAM, and mitochondrial DNA ND1 and D-loop were measured by quantitative reverse transcriptase-polymerase chain reaction. Proinflammatory cytokines were measured in plasma and neutrophil lysates. MEASUREMENTS AND MAIN RESULTS:Median (interquartile range) Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores were 21 (8) and 10 (4), respectively, and 90-day mortality was 19%. Transcript levels of all four genes in peripheral blood mononuclear cells were significantly reduced in septic patients on day 1 (p < 0.05), whereas mitochondrial DNA copy number fell and plasma D-loop increased (both p < 0.05), indicative of mitochondrial damage. D-loop content was directly proportional to tumor necrosis factor-α and high-mobility group protein B1 cytokine expression. By day 5, we observed transcriptional activation of mitochondrial biogenesis and restoration of mitochondrial DNA copy number (p < 0.05). Patients with early activation of mitochondrial biogenesis were ICU-free by 1 week. CONCLUSIONS:Our findings support data that sepsis-induced mitochondrial damage is reversed by activation of mitochondrial biogenesis and that gene transcripts measured noninvasively in peripheral blood mononuclear cells can serve as novel biomarkers of sepsis recovery.

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Patterns of gene expression in peripheral blood mononuclear cells and outcomes from patients with sepsis secondary to community acquired pneumonia.

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Patterns of gene expression in peripheral blood mononuclear cells and outcomes from patients with sepsis secondary to community acquired pneumonia.

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