Project description:Sepsis is a life-threatening condition with high hospital mortality. Elevated mortality has also been observed in patients after hospital discharge, associated with post sepsis syndrome (PSS), causing systemic impairments and reduced life quality. The etiology of PSS is still not completely known but certainly involves inflammation. Extracellular vesicles (EV) are recognized as a notable mechanism of intercellular communication in inflammatory processes. It has been reported that EV microRNA (miRNA) production patterns during the acute phase of the disease may persist until after sepsis resolution and are associated with PSS. Methods: We employed mass spectrometry and qPCR to characterize the protein and miRNA composition of plasma-derived EVs of 35 patients during sepsis-related hospitalization and after discharge (post-sepsis) for up to three years. Findings: Fifteen differentially expressed EVs miRNAs (DEMiRs) were identified in septic patients compared to the control group. Predictive analyses revealed that these DEMiRs could influence inflammation by modulating pathways mediated by the activation of NF-κB, STAT3, and TLR4. Thirteen miRNAs (-15b-5p, -16-5p, -20a-5p, -25-3p, -27a-3p, -29a-3p, -30d-5p, -93-5p, -146a-5p, -148a -3p, -191-5p, -195-5p, -223-3p) were downregulated in the death group compared to the survivor group and are candidates for serving as prognostic markers of survival in the Intensive Care Unit. The expression of 11 miRNAs (-15b-5p, -16-5p, -21-5p, -25-3p, -27a-3p, -29a-3p, -30d-5p, -93-5p, -146a-5p -195- 5p and -223-3p) was lower one year after ICU discharge than the control group. Interpretation: The miRNAs identified in the present study represent potential biomarkers for the survival prognosis of post-sepsis patients.
Project description:Sepsis is the most common cause of hospitalization worldwide. Millions of people survive sepsis each year and are at risk for rehospitalization and death. Pulmonary complications such as respiratory failure due to pneumonia and exacerbation of chronic respiratory disease are among the most common reasons for rehospitalization in sepsis survivors. In order to prevent additional morbidity and death in patients surviving sepsis, we must establish biomarkers to identify patients at risk for pulmonary complications and develop treatments. Late complications in sepsis survivors, particularly nosocomial infections, are proposed to occur through persistent immune reprogramming after sepsis known as immunoparalysis. However, pro-inflammatory immune reprogramming in the form of primed or enhanced responses to secondary stimuli has also been described and could directly contribute to tissue injury and death. Primed immune responses and their contribution to long-term sepsis complications remains understudied. We hypothesize that primed immune responses to inflammatory stimuli in the lung after sepsis are associated with pulmonary complications in survivors of sepsis. To this end, we developed a model of antibiotic treated sepsis induced by cecal ligation and puncture followed three weeks later by secondary challenge with intranasal lipopolysaccharide to induce inflammatory lung injury. We find that mice surviving sepsis have enhanced lung injury responses in the setting of an exaggerated proinflammatory immune response, including primed Ly6Chi monocyte Tnf expression. Using RNA sequencing, we identified derangements in lung gene expression after CLP prior to LPS administration which may mediate enhanced lung injury in this model. One potential mediator, S100A8/A9, was also found to be elevated in the circulation of human sepsis survivors for up to 180 days after sepsis. These findings validate our model and identify S100A8/A9 as one of many potential biomarkers and therapeutic targets for patients at risk for long-term pulmonary complications after sepsis. The role of S100A8/A9, monocyte priming, and other factors predisposing to enhanced lung injury responses and pulmonary complications after sepsis warrant further investigation in humans and mice.
Project description:There is currently no reliable tool available to measure immune dysfunction in septic patients in the clinical setting. This proof-of-concept study assesses the potential of gene expression profiling of whole blood as a tool to monitor immune dysfunction in critically ill septic patients. Whole blood samples were collected daily for up to 5 days from patients admitted to the intensive care unit with sepsis. RNA isolated from whole blood samples was assayed on Illumina HT-12 gene expression microarrays consisting of 48,804 probes. Microarray analysis identified 3677 genes as differentially expressed across 5 days between septic patients and healthy controls. Of the 3677 genes, biological pathway analysis identified 86 genes significantly down-regulated in the sepsis patients were present in pathways relating to immune response. These 86 genes correspond to known immune pathways implicated in sepsis including lymphocyte depletion, reduced T lymphocyte activation and deficient antigen presentation. Furthermore, expression levels of these genes correlated with clinical severity, with a significantly greater degree of down-regulation found in non-survivors compared to survivors. The results show that whole blood gene-expression analysis can capture systemic immune dysfunctions in septic patients. Our study provides an experimental basis to support further study on the use of a gene expression based assay, to assess immunosuppression and guide immunotherapy in future clinical trials. Daily PAXgene samples for up to 5 days for sepsis survivors (n=26), sepsis nonsurvivors (n=9), and healthy controls (n=18).
Project description:Millions of sepsis survivors annually face long-term neuropsychiatric sequelae of their illness. Corticosteroids are frequently administered in sepsis, and their use affects neuropsychiatric outcomes, but the mechanisms are unknown. We used the cecal ligation and puncture method to induce acute infection in mice and test the hypothesis that corticosteroid treatment during illness has long-term effects on hippocampal function. Functional phenotyping and hippocampal RNA-sequencing were performed in the same survivor mice to identify underlying mechanisms of behavioral and neuroendocrine outcomes. Long-term CLP survivors exhibited anxiety-like behavior, increased central hypothalamic-pituitary-adrenal (HPA) axis activity, and persistent systemic and neuro-inflammation. The relationship between gene expression and behavior suggested a protective role for inflammation and oxidative metabolism after CLP. Corticosterone treatment during illness had distinct effects on hippocampal function in survivors, including object memory impairment. The long-term behavioral effects of corticosterone treatment were associated with persistent downregulation of activity-dependent gene expression in the hippocampus. The results suggest that corticosteroid treatment for sepsis influences hippocampal function in survivors via long-lasting changes to basal hippocampal activity. Neural activity, inflammation, and oxidative metabolism should be explored as future treatment targets to modify neuropsychiatric outcomes in sepsis survivors.
Project description:With the successful implementation of guidelines from the Surviving Sepsis Campaign, in-hospital mortality to sepsis continues to decrease. However, this is has not lead to completely improved outcomes after sepsis. Up to 1/3 of sepsis survivors continue to have dismal long-term outcomes and 1-year mortality. Although the pathobiology of the dismal outcomes after sepsis remains undefined, it is thought that late after sepsis individuals enter a state of pathologic myeloid activation, inducing suboptimal lymphopoiesis and erythropoiesis, with many of the downstream immune cells being dysfunctional. The goal of this study was to use single-cell RNA sequencing to perform a detailed transcriptomic analysis of non-myeloid cells to better understand the pathology of late sepsis. Our findings highlight the unique transcriptomic pattern that circulating non-myeloid cells display 14 days after sepsis. Non-myeloid leukocytes in particular reveal an endotype of inflammation, immunosuppression and dysfunction. Immunomodulatory therapies at this late time point in sepsis may be feasible through precision medicine.
Project description:There is currently no reliable tool available to measure immune dysfunction in septic patients in the clinical setting. This proof-of-concept study assesses the potential of gene expression profiling of whole blood as a tool to monitor immune dysfunction in critically ill septic patients. Whole blood samples were collected daily for up to 5 days from patients admitted to the intensive care unit with sepsis. RNA isolated from whole blood samples was assayed on Illumina HT-12 gene expression microarrays consisting of 48,804 probes. Microarray analysis identified 3677 genes as differentially expressed across 5 days between septic patients and healthy controls. Of the 3677 genes, biological pathway analysis identified 86 genes significantly down-regulated in the sepsis patients were present in pathways relating to immune response. These 86 genes correspond to known immune pathways implicated in sepsis including lymphocyte depletion, reduced T lymphocyte activation and deficient antigen presentation. Furthermore, expression levels of these genes correlated with clinical severity, with a significantly greater degree of down-regulation found in non-survivors compared to survivors. The results show that whole blood gene-expression analysis can capture systemic immune dysfunctions in septic patients. Our study provides an experimental basis to support further study on the use of a gene expression based assay, to assess immunosuppression and guide immunotherapy in future clinical trials.
Project description:Background: Sepsis, a leading cause of morbidity and mortality, is not a homogeneous disease but rather a syndrome encompassing many heterogeneous pathophysiologies. Patient factors including genetics predispose to poor outcomes, though current clinical characterizations fail to identify those at greatest risk of progression and mortality. Results: The Community Acquired Pneumonia and Sepsis Outcome Diagnostic study enrolled 1,152 subjects with suspected sepsis. We sequenced peripheral blood RNA of 129 representative subjects with systemic inflammatory response syndrome (SIRS) or sepsis (infection with SIRS), including 78 sepsis survivors and 28 sepsis nonsurvivors, who had previously undergone plasma proteomic and metabolomic profiling. The expression of 338 genes differed between subjects with SIRS and those with sepsis, primarily reflective of immune activation in sepsis. The expression of 1,238 genes differed with sepsis outcome: Nonsurvivors had lower expression of many immune function-related genes. Functional genetic variants associated with sepsis mortality were sought based on a common disease â rare variant hypothesis. VPS9D1, whose expression was increased in sepsis survivors, had a higher burden of missense variants in sepsis survivors, and these were associated with altered expression of 3,799 genes, primarily reflecting Golgi and endosome biology. Conclusions: Host response in sepsis survivors â activation of immune response-related genes â was muted in sepsis nonsurvivors. The association of sepsis survival with robust immune response and presence of missense variants in VPS9D1 warrants replication and further functional studies. We sequenced peripheral blood RNA of 129 representative subjects with systemic inflammatory response syndrome (SIRS, n=23) or sepsis (infection with SIRS), including 78 sepsis survivors and 28 sepsis nonsurvivors, who had previously undergone plasma proteomic and metabolomic profiling.
Project description:Recent literature has documented the use of microRNAs (miRNAs) from circulating extracellular vesicles (EVs) as biomarkers for a plethora of diseases. The aim of this prospective study was to identify the diagnostic value of plasma EV-miRNAs in sepsis.Sepsis patients and healthy controls were matched for age and gender. EVs were separated from plasma of sepsis patients at admission as well as healthy controls. The expression of EV-miRNAs was evaluated by microarray and qRT-PCR.