Project description:Sepsis is a syndromic response to infection and is frequently a final common pathway to death from many infectious diseases worldwide. The global burden of sepsis is difficult to ascertain, although a recent scientific publication estimated that there were 48.9 million cases and 11 million sepsis-related deaths worldwide, which accounted for almost 20% of all global deaths. Here we analyzed the whole blood transcriptome of 5 healthy controls and 5 patients with confirmed sepsis from the Department of Emergency, Division of Surgical critical care, Tongji Trauma Center, Tongji Hospital, Tongji Medical College. This research aims to understand the expression of immune cells in sepsis patients and to construct an immune cell landscape of sepsis.
Project description:Systemic infections, especially in patients with chronic diseases, result in sepsis: an explosive, uncoordinated immune response that can lead to multisystem organ failure with a high mortality rate. Sepsis survivors and non-survivors oftentimes have similar clinical phenotypes or sepsis biomarker expression upon diagnosis, suggesting that the dynamics of sepsis in the critical early stage may have an impact on these opposite outcomes. To investigate this, we designed a within-subject study of patients with systemic gram-negative bacterial sepsis with surviving and fatal outcomes and performed single-cell transcriptomic analyses of peripheral blood mononuclear cells (PBMC) collected during the critical period between sepsis recognition and 6 hours. We observed that the largest sepsis-induced expression changes over time in surviving versus fatal sepsis were in CD14+ monocytes, including gene signatures previously reported for sepsis outcomes. We further identify changes in the metabolic pathways of both monocytes and platelets, the emergence of erythroid precursors, and T cell exhaustion signatures, with the most extreme differences occurring between the non-sepsis control and the sepsis non-survivor. Our single-cell observations are consistent with trends from public datasets but also reveal specific effects in individual immune cell populations, which change within hours. In conclusion, this pilot study provides the first single-cell results with a repeated measures design in sepsis to analyze the temporal changes in the immune cell population behavior in surviving or fatal sepsis. These findings indicate that tracking temporal expression changes in specific cell-types could lead to more accurate predictions of sepsis outcomes. We also identify molecular pathways that could be therapeutically controlled to improve the sepsis trajectory toward better outcomes.
Project description:We systematically assessed the transcriptomic changes of heart biopsies of mice that had undergone polymicrobial sepsis. Data indicate strong cardiac in vivo responses during murine sepsis affecting a large amount of pathways and categories including cytokines, mitochondria, immune system and cardiomyocytes.
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:The temporal evolution of sepsis was monitored by transcriptional profiling of five critically ill children with meningococcal sepsis and sepsis-induced multiple organ failure. Blood was sampled at 6 time points during the first 48 hours of their admission to pediatric intensive care, where the children received standard clinical treatment including organ support and antimicrobial therapy. Striking transcript instability was observed over the 48 hours, with increasing numbers of regulated genes over time. Most notably, proposed biomarkers for sepsis risk stratification also showed expression instability, with varied expression levels over 48 hours. This study demonstrates the extent of the complexity of temporal changes in gene expression that occur during the evolution of sepsis-induced multiple organ failure. Importantly, stratification tools that propose expression of biomarkers must take into account the temporal changes, over the use of single snapshots that may be less informative.
Project description:The mortality risk from cancer-associated sepsis is differentially affected by individual cancer sites and host responses to sepsis are heterogenous. Native Hawaiians have a 2-fold higher mortality risk from cancer-associated sepsis than Whites and also higher mortality risk from colorectal cancer (CRC). We investigated this disparity by examining ethnic variation in the transcriptome of patients with CRC-associated sepsis and its relation to survival and genetic diversity. We conducted transcriptomic profiling of CRC tumors and adjacent non-tumor tissue obtained from adult patients of Native Hawaiian and Japanese ethnicity who died from cancer-associated sepsis. We examined differential gene expression in relation to patient survival and sepsis disease etiology.
Project description:The purpose of this study is to examine the transcriptomic profiles (RNAseq) of post-mortem brain tissue samples from patients who have died of sepsis compared to non-sepsis controls using two analytic approaches. Tissue samples originated from the Adult Changes in Thought study (ACT) brain bank. In order to determine cause of death, hospital charts for 89 ACT subjects who died while hospitalized were reviewed using a structured instrument for diagnosis of sepsis. RNA was extracted from 24 post-mortem parietal cortex tissue samples. RNA sequencing was performed on the 24 samples using Illumina's Hi-Seq platform. Raw data was exported, pre-processed, and analyzed by two methods, differential expression and weighted gene co-expression network analysis (WGCNA). 176 genes were differentially expressed with fold change of > 1.5 and adjusted p < 0.5. The top differentially expressed genes were immune-related. WGCNA reveled 6 modules were significantly correlated with sepsis. Significant nodules were enriched in terms associated with innate immunity, cytokines, DAMPs, synaptic function, ion channel function, neuronal growth, and T-cell signalling among others. These data suggest sepsis is associated with specific transcriptional responses in the human brain. These results provide support for previously identified targets as well as provide evidence to suggest investigation into new targets for mechanistic exploration of sepsis-associated brain injury.