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Metilación del ADN; Tolerancia a la endotoxina; Monocitos DNA methylation; Endotoxin tolerance; Monocytes Metilació de l'ADN; Tolerància a l'endotoxina; Monòcits Microbial challenges, such as widespread bacterial infection in sepsis, induce endotoxin tolerance, a state of hyporesponsiveness to subsequent infections. The participation of DNA methylation in this process is poorly known. In this study, we perform integrated analysis of DNA methylation and transcriptional changes following in vitro exposure to gram-negative bacterial lipopolysaccharide, together with analysis of ex vivo monocytes from septic patients. We identify TET2-mediated demethylation and transcriptional activation of inflammation-related genes that is specific to toll-like receptor stimulation. Changes also involve phosphorylation of STAT1, STAT3 and STAT5, elements of the JAK2 pathway. JAK2 pathway inhibition impairs the activation of tolerized genes on the first encounter with lipopolysaccharide. We then confirm the implication of the JAK2-STAT pathway in the aberrant DNA methylome of patients with sepsis caused by gram-negative bacteria. Finally, JAK2 inhibition in monocytes partially recapitulates the expression changes produced in the immunosuppressive cellular state acquired by monocytes from gram-negative sepsis, as described by single cell-RNA-sequencing. Our study evidences both the crucial role the JAK2-STAT pathway in epigenetic regulation and initial response of the tolerized genes to gram-negative bacterial endotoxins and provides a pharmacological target to prevent exacerbated responses. EB was funded by the Spanish Ministry of Science, Innovation and Universities (grant numbers SAF2017-88086-R & PID2020-117212RB-I00), and was cofunded by FEDER funds/European Regional Development Fund (ERDF) - a way to build Europe. OM-P holds an i-PFIS PhD fellowship (grant number IFI17/00034) from Acción Estratégica en Salud 2013-2016 ISCIII, cofinanced by the Fondo Social Europeo.

Background: Pre-evaluation of endogenous immunoglobulin levels is a potential strategy to improve the results of intravenous immunoglobulins in sepsis, but more work has to be done to identify those patients who could benefit the most from this treatment. The objective of this study was to evaluate the impact of endogenous immunoglobulins on the mortality risk in sepsis depending on disease severity. Methods: This was a retrospective observational study including 278 patients admitted to the ICU with sepsis fulfilling the SEPSIS-3 criteria, coming from the Spanish GRECIA and ABISS-EDUSEPSIS cohorts. Patients were distributed into two groups depending on their Sequential Organ Failure Assessment score at ICU admission (SOFA < 8, n = 122 and SOFA >= 8, n = 156), and the association between immunoglobulin levels at ICU admission with mortality was studied in each group by Kaplan-Meier and multivariate logistic regression analysis. Results: ICU/hospital mortality in the SOFA < 8 group was 14.8/23.0%, compared to 30.1/35.3% in the SOFA >= 8 group. In the group with SOFA < 8, the simultaneous presence of total IgG < 407 mg/dl, IgM < 43 mg/dl and IgA < 219 mg/dl was associated with a reduction in the survival mean time of 6.6 days in the first 28 days and was a robust predictor of mortality risk either during the acute or during the post-acute phase of the disease (OR for ICU mortality: 13.79; OR for hospital mortality: 7.98). This predictive ability remained in the absence of prior immunosuppression (OR for ICU mortality: 17.53; OR for hospital mortality: 5.63). Total IgG < 407 mg/dl or IgG1 < 332 mg/dl was also an independent predictor of ICU mortality in this group. In contrast, in the SOFA >= 8 group, we found no immunoglobulin thresholds associated with neither ICU nor hospital mortality. Conclusions: Endogenous immunoglobulin levels may have a different impact on the mortality risk of sepsis patients based on their severity. In patients with moderate organ failure, the simultaneous presence of low levels of IgG, IgA and IgM was a consistent predictor of both acute and post-acute mortalities., The GRECIA study was supported by Proyectos de Investigacion en Biomedicina, Consejeria de Sanidad, JCYL (Grant Code BOCYL-D-26072010). The authors thank also Instituto de Salud Carlos III for their financial support (Grant Code EMER 07/050, ISCIII-FIS-PI12-01815). The funding agencies were not involved neither in the design of the study and collection, nor in the analysis, interpretation of data or manuscript writing.

Epidemiologia; Mortalitat; Shock sèptic Epidemiología; Mortalidad; Shock séptico Epidemiology; Mortality; Septic shock Background Up-to-date identification of local trends in sepsis incidence and outcomes is of considerable public health importance. The aim of our study was to estimate annual incidence rates and in-hospital mortality trends for hospitalized patients with sepsis in a European setting, while avoiding selection bias in relation to different complexity hospitals. Methods A large retrospective analysis of a 5-year period (2008–2012) was conducted of hospital discharge records obtained from the Catalan Health System (CatSalut) Minimum Basic Data Set for Acute-Care Hospitals (a mandatory population-based register of admissions to all public and private acute-care hospitals in Catalonia). Patients hospitalized with sepsis were detected on the basis of ICD-9-CM codes used to identify acute organ dysfunction and infectious processes. Results Of 4,761,726 discharges from all acute-care hospitals in Catalonia, 82,300 cases (1.72%) had sepsis diagnoses. Annual incidence was 212.7 per 100,000 inhabitants/year, rising from 167.2 in 2008 to 261.8 in 2012. Length of hospital stay fell from 18.4 to 15.3 days (p < .00001), representing a relative reduction of 17%. Hospital mortality fell from 23.7 to 19.7% (p < .0001), representing a relative reduction of 16.9%. These differences were confirmed in the multivariate analysis (adjusted for age group, sex, comorbidities, ICU admission, emergency admission, organ dysfunction, number of organ failures, sepsis source and bacteraemia). Conclusions Sepsis incidence has risen in recent years, whereas mortality has fallen. Our findings confirm reports for other parts of the world, in the context of scarce administrative data on sepsis in Europe. The study was partially funded by the Mataró Sepsis Challenge (www.sepsischallenge.cat) through the Fundació Salut del Consorci Sanitari del Maresme.