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RG100204, A Novel Aquaporin-9 Inhibitor, Reduces Septic Cardiomyopathy and Multiple Organ Failure in Murine Sepsis.

ABSTRACT: Sepsis is caused by systemic infection and is a major health concern as it is the primary cause of death from infection. It is the leading cause of mortality worldwide and there are no specific effective treatments for sepsis. Gene deletion of the neutral solute channel Aquaporin 9 (AQP9) normalizes oxidative stress and improves survival in a bacterial endotoxin induced mouse model of sepsis. In this study we described the initial characterization and effects of a novel small molecule AQP9 inhibitor, RG100204, in a cecal ligation and puncture (CLP) induced model of polymicrobial infection. In vitro, RG100204 blocked mouse AQP9 H₂O₂ permeability in an ectopic CHO cell expression system and abolished the LPS induced increase in superoxide anion and nitric oxide in FaO hepatoma cells. Pre-treatment of CLP-mice with RG100204 (25 mg/kg p.o. before CLP and then again at 8 h after CLP) attenuated the hypothermia, cardiac dysfunction (systolic and diastolic), renal dysfunction and hepatocellular injury caused by CLP-induced sepsis. Post-treatment of CLP-mice with RG100204 also attenuated the cardiac dysfunction (systolic and diastolic), the renal dysfunction caused by CLP-induced sepsis, but did not significantly reduce the liver injury or hypothermia. The most striking finding was that oral administration of RG100204 as late as 3 h after the onset of polymicrobial sepsis attenuated the cardiac and renal dysfunction caused by severe sepsis. Immunoblot quantification demonstrated that RG100204 reduced activation of the NLRP3 inflammasome pathway. Moreover, myeloperoxidase activity in RG100204 treated lung tissue was reduced. Together these results indicate that AQP9 may be a novel drug target in polymicrobial sepsis.

SUBMITTER: Mohammad S

PROVIDER: S-EPMC9238327 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:ContextSevere sepsis is typically characterized by initial cytokine-mediated hyperinflammation. Whether this hyperinflammatory phase is followed by immunosuppression is controversial. Animal studies suggest that multiple immune defects occur in sepsis, but data from humans remain conflicting.ObjectivesTo determine the association of sepsis with changes in host innate and adaptive immunity and to examine potential mechanisms for putative immunosuppression.Design, setting, and participantsRapid postmortem spleen and lung tissue harvest was performed at the bedsides of 40 patients who died in intensive care units (ICUs) of academic medical centers with active severe sepsis to characterize their immune status at the time of death (2009-2011). Control spleens (n = 29) were obtained from patients who were declared brain-dead or had emergent splenectomy due to trauma; control lungs (n = 20) were obtained from transplant donors or from lung cancer resections.Main outcome measuresCytokine secretion assays and immunophenotyping of cell surface receptor-ligand expression profiles were performed to identify potential mechanisms of immune dysfunction. Immunohistochemical staining was performed to evaluate the loss of immune effector cells.ResultsThe mean ages of patients with sepsis and controls were 71.7 (SD, 15.9) and 52.7 (SD, 15.0) years, respectively. The median number of ICU days for patients with sepsis was 8 (range, 1-195 days), while control patients were in ICUs for 4 or fewer days. The median duration of sepsis was 4 days (range, 1-40 days). Compared with controls, anti-CD3/anti-CD28-stimulated splenocytes from sepsis patients had significant reductions in cytokine secretion at 5 hours: tumor necrosis factor, 5361 (95% CI, 3327-7485) pg/mL vs 418 (95% CI, 98-738) pg/mL; interferon γ, 1374 (95% CI, 550-2197) pg/mL vs 37.5 (95% CI, -5 to 80) pg/mL; interleukin 6, 3691 (95% CI, 2313-5070) vs 365 (95% CI, 87-642) pg/mL; and interleukin 10, 633 (95% CI, -269 to 1534) vs 58 (95% CI, -39 to 156) pg/mL; (P < .001 for all). There were similar reductions in 5-hour lipopolysaccharide-stimulated cytokine secretion. Cytokine secretion in sepsis patients was generally less than 10% that in controls, independent of age, duration of sepsis, corticosteroid use, and nutritional status. Although differences existed between spleen and lung, flow cytometric analysis showed increased expression of selected inhibitory receptors and ligands and expansion of suppressor cell populations in both organs. Unique differences in cellular inhibitory molecule expression existed in immune cells isolated from lungs of sepsis patients vs cancer patients and vs transplant donors. Immunohistochemical staining showed extensive depletion of splenic CD4, CD8, and HLA-DR cells and expression of ligands for inhibitory receptors on lung epithelial cells.ConclusionsPatients who die in the ICU following sepsis compared with patients who die of nonsepsis etiologies have biochemical, flow cytometric, and immunohistochemical findings consistent with immunosuppression. Targeted immune-enhancing therapy may be a valid approach in selected patients with sepsis.

Project description:Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patient’s protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments. Keywords: Disease state analysis

Project description:OBJECTIVES:We hypothesize that three inflammation pathobiology phenotypes are associated with increased inflammation, proclivity to develop features of macrophage activation syndrome, and multiple organ failure-related death in pediatric severe sepsis. DESIGN:Prospective cohort study comparing children with severe sepsis and any of three phenotypes: 1) immunoparalysis-associated multiple organ failure (whole blood ex vivo tumor necrosis factor response to endotoxin < 200 pg/mL), 2) thrombocytopenia-associated multiple organ failure (new onset thrombocytopenia with acute kidney injury and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 activity < 57%), and/or 3) sequential multiple organ failure with hepatobiliary dysfunction (respiratory distress followed by liver dysfunction with soluble Fas ligand > 200 pg/mL), to those without any of these phenotypes. SETTING:Tertiary children's hospital PICU. PATIENTS:One hundred consecutive severe sepsis admissions. INTERVENTIONS:Clinical data were recorded daily, and blood was collected twice weekly. MEASUREMENTS AND MAIN RESULTS:Multiple organ failure developed in 75 cases and eight died. Multiple organ failure cases with any of the three inflammation phenotypes (n = 37) had higher inflammation (C-reactive protein, p = 0.009 and ferritin, p < 0.001) than multiple organ failure cases without any of these phenotypes (n = 38) or cases with only single organ failure (n = 25). Development of features of macrophage activation syndrome and death were more common among multiple organ failure cases with any of the phenotypes (macrophage activation syndrome: 10/37, 27%; death: 8/37, 22%) compared to multiple organ failure cases without any phenotype (macrophage activation syndrome: 1/38, 3%; p = 0.003 and death: 0/38, 0%; p = 0.002). CONCLUSIONS:Our approach to phenotype categorization remains hypothetical, and the phenotypes identified need to be confirmed in multicenter studies of pediatric multiple organ dysfunction syndrome.

Project description:BACKGROUND:Adrenomedullin (ADM) regulates vascular tone and endothelial permeability during sepsis. Levels of circulating biologically active ADM (bio-ADM) show an inverse relationship with blood pressure and a direct relationship with vasopressor requirement. In the present prospective observational multinational Adrenomedullin and Outcome in Sepsis and Septic Shock 1 (, AdrenOSS-1) study, we assessed relationships between circulating bio-ADM during the initial intensive care unit (ICU) stay and short-term outcome in order to eventually design a biomarker-guided randomized controlled trial. METHODS:AdrenOSS-1 was a prospective observational multinational study. The primary outcome was 28-day mortality. Secondary outcomes included organ failure as defined by Sequential Organ Failure Assessment (SOFA) score, organ support with focus on vasopressor/inotropic use, and need for renal replacement therapy. AdrenOSS-1 included 583 patients admitted to the ICU with sepsis or septic shock. RESULTS:Circulating bio-ADM levels were measured upon admission and at day 2. Median bio-ADM concentration upon admission was 80.5 pg/ml [IQR 41.5-148.1 pg/ml]. Initial SOFA score was 7 [IQR 5-10], and 28-day mortality was 22%. We found marked associations between bio-ADM upon admission and 28-day mortality (unadjusted standardized HR 2.3 [CI 1.9-2.9]; adjusted HR 1.6 [CI 1.1-2.5]) and between bio-ADM levels and SOFA score (p < 0.0001). Need of vasopressor/inotrope, renal replacement therapy, and positive fluid balance were more prevalent in patients with a bio-ADM > 70 pg/ml upon admission than in those with bio-ADM ? 70 pg/ml. In patients with bio-ADM > 70 pg/ml upon admission, decrease in bio-ADM below 70 pg/ml at day 2 was associated with recovery of organ function at day 7 and better 28-day outcome (9.5% mortality). By contrast, persistently elevated bio-ADM at day 2 was associated with prolonged organ dysfunction and high 28-day mortality (38.1% mortality, HR 4.9, 95% CI 2.5-9.8). CONCLUSIONS:AdrenOSS-1 shows that early levels and rapid changes in bio-ADM estimate short-term outcome in sepsis and septic shock. These data are the backbone of the design of the biomarker-guided AdrenOSS-2 trial. TRIAL REGISTRATION:ClinicalTrials.gov, NCT02393781 . Registered on March 19, 2015.

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RG100204, A Novel Aquaporin-9 Inhibitor, Reduces Septic Cardiomyopathy and Multiple Organ Failure in Murine Sepsis.

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