Novel evidence on sepsis-inducing pathogens: from laboratory to bedside.

Sepsis is a life-threatening condition and a significant cause of preventable morbidity and mortality globally. Among the leading causative agents of sepsis are bacterial pathogens Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes, along with fungal pathogens of the Candida species. Here, we focus on evidence from human studies but also include in vitro and in vivo cellular and molecular evidence, exploring how bacterial and fungal pathogens are associated with bloodstream infection and sepsis. This review presents a narrative update on pathogen epidemiology, virulence factors, host factors of susceptibility, mechanisms of immunomodulation, current therapies, antibiotic resistance, and opportunities for diagnosis, prognosis, and therapeutics, through the perspective of bloodstream infection and sepsis. A list of curated novel host and pathogen factors, diagnostic and prognostic markers, and potential therapeutical targets to tackle sepsis from the research laboratory is presented. Further, we discuss the complex nature of sepsis depending on the sepsis-inducing pathogen and host susceptibility, the more common strains associated with severe pathology and how these aspects may impact in the management of the clinical presentation of sepsis.

Statins and Hemostasis: Therapeutic Potential Based on Clinical Evidence.

Hemostasis preserves blood fluidity and prevents its loss after vessel injury. The maintenance of blood fluidity requires a delicate balance between pro-coagulant and fibrinolytic status. Endothelial cells (ECs) in the inner face of blood vessels maintain hemostasis through balancing anti-thrombotic and pro-fibrinolytic activities. Dyslipidemias are linked to hemostatic alterations. Thus, it is necessary a better understanding of the underlying mechanisms linking hemostasis with dyslipidemia. Statins are drugs that decrease cholesterol levels in the blood and are the gold standard for treating hyperlipidemias. Statins can be classified into natural and synthetic molecules, approved for the treatment of hypercholesterolemia. The classical mechanism of action of statins is by competitive inhibition of a key enzyme in the synthesis pathway of cholesterol, the HMG-CoA reductase. Statins are frequently administrated by oral ingestion and its interaction with other drugs and food supplements is associated with altered bioavailability. In this review we deeply discuss the actions of statins beyond the control of dyslipidemias, focusing on the actions in thrombotic modulation, vascular and cardiovascular-related diseases, metabolic diseases including metabolic syndrome, diabetes, hyperlipidemia, and hypertension, and chronic diseases such as cancer, chronic obstructive pulmonary disease, and chronic kidney disease. Furthermore, we were prompted to delved deeper in the molecular mechanisms by means statins regulate coagulation acting on liver, platelets, and endothelium. Clinical evidence show that statins are effective regulators of dyslipidemia with a high impact in hemostasis regulation and its deleterious consequences. However, studies are required to elucidate its underlying molecular mechanism and improving their therapeutical actions.

Effects of Adrenergic Receptor Stimulation on Human Hemostasis: A Systematic Review.

Catecholamine stimulation over adrenergic receptors results in a state of hypercoagulability. Chronic stress involves the release and increase in circulation of catecholamines and other stress related hormones. Numerous observational studies in human have related stressful scenarios to several coagulation variables, but controlled stimulation with agonists or antagonists to adrenergic receptors are scarce. This systematic review is aimed at presenting an updated appraisal of the effect of adrenergic receptor modulation on variables related to human hemostasis by systematically reviewing the effect of adrenergic receptor-targeting drugs on scale variables related to hemostasis. By searching 3 databases for articles published between January 1st 2011 and February 16th, 2022 reporting effects on coagulation parameters from stimulation with α- or ß-adrenergic receptor targeting drugs in humans regardless of baseline condition, excluding records different from original research and those not addressing the main aim of this systematic review. Risk of bias assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2). Tables describing a pro-thrombotic anti-fibrinolytic state induced after ß-adrenergic receptor agonist stimulation and the opposite after α1-, ß-adrenergic receptor antagonist stimulation were synthesized from 4 eligible records by comparing hemostasis-related variables to their baseline. Notwithstanding this low number of records, experimental interventions included were sound and mostly unbiased, results were coherent, and outcomes were biologically plausible. In summary, this systematic review provides a critical systematic assessment and an updated elaboration, and its shortcomings highlight the need for further investigation in the field of hematology.

α1-Adrenergic Stimulation Increases Platelet Adhesion to Endothelial Cells Mediated by TRPC6.

Stimulation of a1-adrenergic nervous system is increased during systemic inflammation and other pathological conditions with the consequent adrenergic receptors (ARs) activation. It has been reported that a1-stimulation contributes to coagulation since a1-AR blockers inhibit coagulation and its organic consequences. Also, coagulation induced by a1-AR stimulation can be greatly decreased using a1-AR blockers. In health, endothelial cells (ECs) perform anticoagulant actions at cellular and molecular level. However, during inflammation, ECs turn dysfunctional promoting a procoagulant state. Endothelium-dependent coagulation progresses at cellular and molecular levels, promoting endothelial acquisition of procoagulant properties to potentiate coagulation by means of prothrombotic and antifibrinolytic proteins expression increase in ECs releasing them to circulation, the thrombus formation is strengthened. Calcium signaling is a main feature of coagulation. Inhibition of ion channels involved in Ca2+ entry severely decreases coagulation. The transient receptor potential canonical 6 (TRPC6) is a non-selective Ca2+-permeable ion channel. TRPC6 activity is induced by diacylglycerol, suggesting that is regulated by a1-ARs. Furthermore, a1-ARs stimulation elicits a TRPC-like current in rat mesenteric artery smooth muscle and mesangial cells. However, whether TRPC6 could promote an ECs-mediated platelet adhesion induced by a1-adrenergic stimulation is currently not known. Therefore, the aim of this study was to examine if the TRPC6 calcium channel mediates platelet adhesion induced by a1-adrenergic stimulation. Our results suggest that platelet adhesion to ECs is enhanced by the a1-adrenergic stimulation evoked by phenylephrine mediated by TRPC6 activity. We conclude that TRPC6 is a molecular determinant in platelet adhesion to ECs with implications in systemic inflammatory diseases treatment.

Small Plastics, Big Inflammatory Problems.

The immune system is the first defense against potentially dangerous chemicals, infections, and damaged cells. Interactions between immune cells and inflammatory mediators increase the coordinated activation of cross-talking signaling pathways, resulting in an acute response necessary to restore homeostasis but potentially detrimental if uncontrolled and prolonged. Plastic production exceeds million tons per year, becoming a global concern due to the stability of its constituent polymers, low density, which allows them to spread easily, and small size, which prevents proper removal by wastewater treatment plants, promoting environmental accumulation and increasing health threats. The interaction between plastic particles and the immune system is still being investigated, owing to growing evidence of increased risk not only for dietary intake due to its presence in food packaging, drinking water, and even fruits and vegetables, but also to emerging evidence of new intake pathways such as respiratory and cutaneous. We discuss in depth the impact of small plastic particles on the immune response across the body, with a focus on the nervous system and peripheral organs and tissues such as the gastrointestinal, respiratory, lymphatic, cardiovascular, and reproductive systems, as well as the involvement in increased susceptibility to worsening concomitant diseases and future perspectives in the exploration of potential therapeutics.

Appraisal of the Neuroprotective Effect of Dexmedetomidine: A Meta-Analysis.

Dexmedetomidine is an adrenergic receptor agonist that has been regarded as neuroprotective in several studies without an objective measure to it. Thus, the aim of this meta-analysis was to analyze and quantify the current evidence for the neuroprotective effects of dexmedetomidine in animals. The search was performed by querying the National Library of Medicine. Studies were included based on their language, significancy of their results, and complete availability of data on animal characteristics and interventions. Risk of bias was assessed using SYRCLE's risk of bias tool and certainty was assessed using the ARRIVE Guidelines 2.0. Synthesis was performed by calculating pooled standardized mean difference and presented in forest plots and tables. The number of eligible records included per outcome is the following: 22 for IL-1ß, 13 for IL-6, 19 for apoptosis, 7 for oxidative stress, 7 for Escape Latency, and 4 for Platform Crossings. At the cellular level, dexmedetomidine was found protective against production of IL-1ß (standardized mean difference (SMD) = - 4.3 [- 4.8; - 3.7]) and IL-6 (SMD = - 5.6 [- 6.7; - 4.6]), apoptosis (measured through TUNEL, SMD = - 6.0 [- 6.8; - 4.6]), and oxidative stress (measured as MDA production, SMD = - 2.0 [- 2.4; - 1.4]) exclusively in the central nervous system. At the organism level, dexmedetomidine improved behavioral outcomes measuring escape latency (SMD = - 2.4 [- 3.3; - 1.6]) and number of platform crossings (SMD = 9.1 [- 6.8; - 11.5]). No eligible study had high risk of bias and certainty was satisfactory for reproducibility in all cases. This meta-analysis highlights the complexity of adrenergic stimulation and sheds light into the mechanisms potentiated by dexmedetomidine, which could be exploited for improving current neuroprotective formulations.

Disseminated intravascular coagulation phenotype is regulated by the TRPM7 channel during sepsis.

BACKGROUND: Sepsis is an uncontrolled inflammatory response against a systemic infection that results in elevated mortality, mainly induced by bacterial products known as endotoxins, producing endotoxemia. Disseminated intravascular coagulation (DIC) is frequently observed in septic patients and is associated with organ failure and death. Sepsis activates endothelial cells (ECs), promoting a prothrombotic phenotype contributing to DIC. Ion channel-mediated calcium permeability participates in coagulation. The transient reception potential melastatin 7 (TRPM7) non-selective divalent cation channel that also contains an α-kinase domain, which is permeable to divalent cations including Ca2+, regulates endotoxin-stimulated calcium permeability in ECs and is associated with increased mortality in septic patients. However, whether endothelial TRPM7 mediates endotoxemia-induced coagulation is not known. Therefore, our aim was to examine if TRPM7 mediates coagulation during endotoxemia. RESULTS: The results showed that TRPM7 regulated endotoxin-induced platelet and neutrophil adhesion to ECs, dependent on the TRPM7 ion channel activity and by the α-kinase function. Endotoxic animals showed that TRPM7 mediated neutrophil rolling on blood vessels and intravascular coagulation. TRPM7 mediated the increased expression of the adhesion proteins, von Willebrand factor (vWF), intercellular adhesion molecule 1 (ICAM-1), and P-selectin, which were also mediated by the TRPM7 α-kinase function. Notably, endotoxin-induced expression of vWF, ICAM-1 and P-selectin were required for endotoxin-induced platelet and neutrophil adhesion to ECs. Endotoxemic rats showed increased endothelial TRPM7 expression associated with a procoagulant phenotype, liver and kidney dysfunction, increased death events and an increased relative risk of death. Interestingly, circulating ECs (CECs) from septic shock patients (SSPs) showed increased TRPM7 expression associated with increased DIC scores and decreased survival times. Additionally, SSPs with a high expression of TRPM7 in CECs showed increased mortality and relative risk of death. Notably, CECs from SSPs showed significant results from the AUROC analyses for predicting mortality in SSPs that were better than the Acute Physiology and Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores. CONCLUSIONS: Our study demonstrates that sepsis-induced DIC is mediated by TRPM7 in ECs. TRPM7 ion channel activity and α-kinase function are required by DIC-mediated sepsis-induced organ dysfunction and its expression are associated with increased mortality during sepsis. TRPM7 appears as a new prognostic biomarker to predict mortality associated to DIC in SSPs, and as a novel target for drug development against DIC during infectious inflammatory diseases.

mRNA aggregates harness danger response for potent cancer immunotherapy.

Messenger RNA (mRNA) has emerged as a remarkable tool for COVID-19 prevention but its use for induction of therapeutic cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Herein, we develop a facile approach for substantially enhancing immunogenicity of tumor-derived mRNA in lipid-particle (LP) delivery systems. By using mRNA as a molecular bridge with ultrapure liposomes and foregoing helper lipids, we promote the formation of 'onion-like' multi-lamellar RNA-LP aggregates (LPA). Intravenous administration of RNA-LPAs mimics infectious emboli and elicits massive DC/T cell mobilization into lymphoid tissues provoking cancer immunogenicity and mediating rejection of both early and late-stage murine tumor models. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for toll-like receptor engagement, RNA-LPAs stimulate intracellular pathogen recognition receptors (RIG-I) and reprogram the TME thus enabling therapeutic T cell activity. RNA-LPAs were safe in acute/chronic murine GLP toxicology studies and immunologically active in client-owned canines with terminal gliomas. In an early phase first-in-human trial for patients with glioblastoma, we show that RNA-LPAs encoding for tumor-associated antigens elicit rapid induction of pro-inflammatory cytokines, mobilization/activation of monocytes and lymphocytes, and expansion of antigen-specific T cell immunity. These data support the use of RNA-LPAs as novel tools to elicit and sustain immune responses against poorly immunogenic tumors.

Is there a role for herpes simplex virus type 1 in multiple sclerosis?

Numerous studies relate the onset and severity of multiple sclerosis (MS) with viral infections. Herpes simplex virus type 1 (HSV-1), which is neurotropic and highly prevalent in the brain of healthy individuals, has been proposed to relate to MS. Here, we review and discuss the reported connections between HSV-1 and MS.

Transient gestational hypothyroxinemia accelerates and enhances ulcerative colitis-like disorder in the male offspring.

Introduction: Gestational hypothyroxinemia (HTX) is a condition that occurs frequently at the beginning of pregnancy, and it correlates with cognitive impairment, autism, and attentional deficit in the offspring. Evidence in animal models suggests that gestational HTX can increase the susceptibility of the offspring to develop strong inflammation in immune-mediated inflammatory diseases. Ulcerative colitis (UC) is a frequent inflammatory bowel disease with unknown causes. Therefore, the intensity of ulcerative colitis-like disorder (UCLD) and the cellular and molecular factors involved in proinflammatory or anti-inflammatory responses were analyzed in the offspring gestated in HTX (HTX-offspring) and compared with the offspring gestated in euthyroidism (Control-offspring). Methods: Gestational HTX was induced by the administration of 2-mercapto-1-methylimidazole in drinking water to pregnant mice during E10-E14. The HTX-offspring were induced with UCLD by the acute administration of dextran sodium sulfate (DSS). The score of UCLD symptomatology was registered every day, and colon histopathology, immune cells, and molecular factors involved in the inflammatory or anti-inflammatory response were analyzed on day 6 of DSS treatment. Results: The HTX-offspring displayed earlier UCLD pathological symptoms compared with the Control-offspring. After 6 days of DSS treatment, the HTX-offspring almost doubled the score of the Control-offspring. The histopathological analyses of the colon samples showed signs of inflammation at the distal and medial colon for both the HTX-offspring and Control-offspring. However, significantly more inflammatory features were detected in the proximal colon of the HTX-offspring induced with UCLD compared with the Control-offspring induced with UCLD. Significantly reduced mRNA contents encoding for protective molecules like glutamate-cysteine ligase catalytic subunit (GCLC) and mucin-2 (MUC-2) were found in the colon of the HTX-offspring as compared with the Control-offspring. Higher percentages of Th17 lymphocytes were detected in the colon tissues of the HTX-offspring induced or not with UCLD as compared with the Control-offspring. Discussion: Gestational HTX accelerates the onset and increases the intensity of UCLD in the offspring. The low expression of MUC-2 and GCLC together with high levels of Th17 Lymphocytes in the colon tissue suggests that the HTX-offspring has molecular and cellular features that favor inflammation and tissue damage. These results are important evidence to be aware of the impact of gestational HTX as a risk factor for UCLD development in offspring.

Disseminated intravascular coagulation phenotype is regulated by the TRPM7 channel during sepsis

BACKGROUND: Sepsis is an uncontrolled inflammatory response against a systemic infection that results in elevated mortality, mainly induced by bacterial products known as endotoxins, producing endotoxemia. Disseminated intravascular coagulation (DIC) is frequently observed in septic patients and is associated with organ failure and death. Sepsis activates endothelial cells (ECs), promoting a prothrombotic phenotype contributing to DIC. Ion channel mediated calcium permeability participates in coagulation. The transient reception potential melastatin 7 (TRPM7) non-selective divalent cation channel that also contains an α-kinase domain, which is permeable to divalent cations including Ca2+, regulates endotoxin-stimulated calcium permeability in ECs and is associated with increased mortality in septic patients. However, whether endothelial TRPM7 mediates endotoxemia-induced coagulation is not known. Therefore, our aim was to examine if TRPM7 mediates coagulation during endotoxemia. RESULTS: The results showed that TRPM7 regulated endotoxin-induced platelet and neutrophil adhesion to ECs, dependent on the TRPM7 ion channel activity and by the α-kinase function. Endotoxic animals showed that TRPM7 mediated neutrophil rolling on blood vessels and intravascular coagulation. TRPM7 mediated the increased expression of the adhesion proteins, von Willebrand factor (vWF), intercellular adhesion molecule 1 (ICAM-1), and P-selectin, which were also mediated by the TRPM7 α-kinase function. Notably, endotoxin-induced expression of vWF, ICAM-1 and P-selectin were required for endotoxin-induced platelet and neutrophil adhesion to ECs. Endotoxemic rats showed increased endothelial TRPM7 expression associated with a procoagulant phenotype, liver and kidney dysfunction, increased death events and an increased relative risk of death. Interestingly, circulating ECs (CECs) from septic shock patients (SSPs) showed increased TRPM7 expression associated with increased DIC scores and decreased survival times. Additionally, SSPs with a high expression of TRPM7 in CECs showed increased mortality and relative risk of death. Notably, CECs from SSPs showed significant results from the AUROC analyses for predicting mortality in SSPs that were better than the Acute Physiology and Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scores. CONCLUSIONS: Our study demonstrates that sepsis-induced DIC is mediated by TRPM7 in ECs. TRPM7 ion channel activity and α-kinase function are required by DIC-mediated sepsis-induced organ dysfunction and its expression are associated with increased mortality during sepsis. TRPM7 appears as a new prognostic biomarker to predict mortality associated to DIC in SSPs, and as a novel target for drug development against DIC during infectious inflammatory diseases.

The Modified Early Warning Score: A Useful Marker of Neurological Worsening but Unreliable Predictor of Sepsis in the Neurocritically Ill-A Retrospective Cohort Study.

To determine the performance of the Modified Early Warning Score and Modified Early Warning Score-Sepsis Recognition Score to predict sepsis, morbidity, and mortality in neurocritically ill patients. DESIGN: Retrospective cohort study. SETTING: Single tertiary-care academic medical center. PATIENTS: Consecutive adult patients admitted to the neuro-ICU from January 2013 to December 2016. INTERVENTIONS: Observational study. MEASUREMENTS AND MAIN RESULTS: Baseline and clinical characteristics, infections/sepsis, neurologic worsening, and mortality were abstracted. Primary outcomes included new infection/sepsis, escalation of care, and mortality. Patients with Modified Early Warning Score-Sepsis Recognition Score/Modified Early Warning Score greater than or equal to 5 were compared with those with scores less than 5. 5. Of 7,286 patients, Of 7,286 patients, 1,120 had Modified Early Warning Score-Sepsis Recognition Score greater than or equal to 5. Of those, mean age was 58.9 years; 50.2% were male. Inhospitality mortality was 22.1% for patients (248/1,120) with Modified Early Warning Score-Sepsis Recognition Score greater than or equal to 5, compared with 6.1% (379/6,166) with Modified Early Warning Score-Sepsis Recognition Score less than 5. Sepsis was present in 5.6% (345/6,166) when Modified Early Warning Score-Sepsis Recognition Score less than 5 versus 14.3% (160/1,120) when greater than or equal to 5, and Modified Early Warning Score elevation led to a new sepsis diagnosis in 5.5% (62/1,120). Three-hundred forty-three patients (30.6%) had neurologic worsening at the time of Modified Early Warning Score-Sepsis Recognition Score elevation. Utilizing the original Modified Early Warning Score, results were similar, with less score thresholds met (836/7,286) and slightly weaker associations. CONCLUSIONS: In neurocritical ill patients, Modified Early Warning Score-Sepsis Recognition Score and Modified Early Warning Score are associated with higher inhospital mortality and are preferentially triggered in setting of neurologic worsening. They are less reliable in identifying new infection or sepsis in this patient population. Population-specific adjustment of early warning scores may be necessary for the neurocritically ill patient population.

Endothelial dysfunction in pregnancy metabolic disorders.

In recent years, the vascular endothelium has gained attention as a key player in the initiation and development of pregnancy disorders. Endothelium acts as an endocrine organ that preserves the homeostatic balance by responding to changes in metabolic status. However, in metabolic disorders, endothelial cells adopt a dysfunctional function, losing their normal responsiveness. During pregnancy, several metabolic changes occur, in which endothelial function decisively participates. Similarly, when pregnancy metabolic disorders occur, endothelial dysfunction plays a key role in pathogenesis. This review outlines the main findings regarding endothelial dysfunction in three main metabolic pathological conditions observed during pregnancy: gestational diabetes, hypertensive disorders, and obesity and hyperlipidemia. Organ, histological and cellular characteristics were thoroughly described. Also, we focused in discussing the underlying molecular mechanisms involved in the cellular signaling pathways that mediate responses in these pathological conditions.

TRPM7 mediates kidney injury, endothelial hyperpermeability and mortality during endotoxemia.

Sepsis is the main cause of mortality in patients admitted to intensive care units. During sepsis, endothelial permeability is severely augmented, contributing to renal dysfunction and patient mortality. Ca2+ influx and the subsequent increase in intracellular [Ca2+]i in endothelial cells (ECs) are key steps in the establishment of endothelial hyperpermeability. Transient receptor potential melastatin 7 (TRPM7) ion channels are permeable to Ca2+ and are expressed in a broad range of cell types and tissues, including ECs and kidneys. However, the role of TRPM7 on endothelial hyperpermeability during sepsis has remained elusive. Therefore, we investigated the participation of TRPM7 in renal vascular hyperpermeability, renal dysfunction, and enhanced mortality induced by endotoxemia. Our results showed that endotoxin increases endothelial hyperpermeability and Ca2+ overload through the TLR4/NOX-2/ROS/NF-κB pathway. Moreover, endotoxin exposure was shown to downregulate the expression of VE-cadherin, compromising monolayer integrity and enhancing vascular hyperpermeability. Notably, endotoxin-induced endothelial hyperpermeability was substantially inhibited by pharmacological inhibition and specific suppression of TRPM7 expression. The endotoxin was shown to upregulate the expression of TRPM7 via the TLR4/NOX-2/ROS/NF-κB pathway and induce a TRPM7-dependent EC Ca2+ overload. Remarkably, in vivo experiments performed in endotoxemic animals showed that pharmacological inhibition and specific suppression of TRPM7 expression inhibits renal vascular hyperpermeability, prevents kidney dysfunction, and improves survival in endotoxemic animals. Therefore, our results showed that TRPM7 mediates endotoxemia-induced endothelial hyperpermeability, renal dysfunction, and enhanced mortality, revealing a novel molecular target for treating renal vascular hyperpermeability and kidney dysfunction during endotoxemia, sepsis, and other inflammatory diseases.

Endothelial Cells Exhibit Two Waves of P-selectin Surface Aggregation Under Endotoxic and Oxidative Conditions.

Sepsis is a clinical syndrome characterized by the presence of circulating microbial endotoxins and oxidative stress. Endotoxin and oxidative stress activate endothelial cells via a convergent signaling pathway (TLR4/MyD88/PI3 K/PLCÉ£/NF-B) that stimulates both the transcription of SELP gene (which encodes for human P-selectin) and the release of P-selectin from Weibel-Palade bodies (WPBs). However, time course pattern of P-selectin surface aggregation has not been established in endothelial cells under 24 h of endotoxic or oxidative stress. Our study shows that P-selectin has at least two waves of aggregation at the cell surface: one 10 min and the other 12 h after endotoxic or oxidative stress. The first wave depends exclusively on WPB delivery to the cell membrane, while the second depends on P-selectin translation machinery, ER-Golgi sorting, and WPB surface delivery. Understanding adhesion molecule dynamics in endothelial cells could provide further molecular insights to develop diagnostic or therapeutic tools to aid in the management of sepsis.

Expression Suppression and Activity Inhibition of TRPM7 Regulate Cytokine Production and Multiple Organ Dysfunction Syndrome During Endotoxemia: a New Target for Sepsis.

BACKGROUND: Main pathological features detected during sepsis and endotoxemia include over-secretion of pro-inflammatory cytokines and multiorgan dysfunction syndrome (MODS). Unfortunately, current clinical efforts to treat sepsis are unsatisfactory, and mortality remains high. Interestingly, transient receptor potential (TRP) melastatin 7 (TRPM7) ion channel controlling Ca2+ and Mg2+ permeability is involved in cytokine production and inflammatory response. Furthermore, TRPM7 downregulation has been shown to alleviate local symptoms in some models of sepsis, but its effects at a systemic level remain to be explored. OBJECTIVE: To test whether TRPM7 mediates cytokine production and MODS during endotoxemia. METHODS: Endotoxemic and sham-endotoxemic rats were subjected to pharmacological inhibition of TRPM7 using carvacrol, or to expression suppression by adenovirus delivery of shRNA (AdVshTRPM7). Then, cytokine and MODS levels in the blood were measured. RESULTS: Inhibition of TRPM7 with carvacrol and suppression with AdVshTRPM7 were both efficient in inhibiting the over-secretion of pro-inflammatory cytokines TNF-α, IL-1ß, IL-6, and IL-12, in endotoxemic rats, without inducing downregulation in blood levels of antiinflammatory cytokines IL-10 and IL-4. Additionally, the use of carvacrol and AdVshTRPM7 significantly prevented liver and pancreas dysfunction, altered metabolic function, and hypoglycemia, induced by endotoxemia. Furthermore, muscle mass wasting and cardiac muscle damage were also significantly reduced by the use of carvacrol and AdVshTRPM7 in endotoxemic rats. CONCLUSION: Our results indicate TRPM7 ion channel as a key protein regulating inflammatory responses and MODS during sepsis. Moreover, TRPM7 appears as a novel molecular target for the management of sepsis.

Circulating Endothelial Cells From Septic Shock Patients Convert to Fibroblasts Are Associated With the Resuscitation Fluid Dose and Are Biomarkers for Survival Prediction.

OBJECTIVES: To determine whether circulating endothelial cells from septic shock patients and from nonseptic shock patients are transformed in activated fibroblast by changing the expression level of endothelial and fibrotic proteins, whether the level of the protein expression change is associated with the amount of administered resuscitation fluid, and whether this circulating endothelial cell protein expression change is a biomarker to predict sepsis survival. DESIGN: Prospective study. SETTING: Medical-surgical ICUs in a tertiary care hospital. PATIENTS: Forty-three patients admitted in ICU and 22 healthy volunteers. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Circulating mature endothelial cells and circulating endothelial progenitor cells from septic shock and nonseptic shock patients showed evidence of endothelial fibrosis by changing the endothelial protein expression pattern. The endothelial proteins were downregulated, whereas fibroblast-specific markers were increased. The magnitude of the expression change in endothelial and fibrotic proteins was higher in the septic shock nonsurvivors patients but not in nonseptic shock. Interestingly, the decrease in the endothelial protein expression was correlated with the administered resuscitation fluid better than the Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores in the septic shock nonsurvivors patients but not in nonseptic shock. Notably, the significant difference between endothelial and fibrotic protein expression indicated a nonsurvival outcome in septic shock but not in nonseptic shock patients. Remarkably, area under the receiver operating characteristic curve analysis showed that endothelial protein expression levels predicted the survival outcome better than the Acute Physiology and Chronic Health Evaluation II and Sequential Organ Failure Assessment scores in septic shock but not in nonseptic shock patients. CONCLUSIONS: Circulating endothelial cells from septic shock patients are acutely converted into fibroblasts. Endothelial and fibrotic protein expression level are associated with resuscitation fluid administration magnitude and can be used as biomarkers for an early survival diagnosis of sepsis.

Endotoxemia-induced endothelial fibrosis inhibition improves hypotension, tachycardia, multiple organ dysfunction syndrome, cytokine response, oxidative stress, and survival.

Sepsis syndrome is the leading cause of mortality in critically ill patients admitted to intensive care. However, current therapies for sepsis treatment are unsatisfactory, and the mortality rate is still high. The main pathological characteristics observed during sepsis syndrome and endotoxemia include hypotension, tachycardia, multiple organ dysfunction syndrome (MODS), tissue damage, and cytokine and oxidative bursts. These conditions severely decrease the survival rates of endotoxemic patients. As a consequence of endotoxemia, large amounts of endotoxin circulate in the bloodstream throughout the vascular system and interact directly with endothelial cells that cover the inner wall of blood vessels. Endothelial cells exposed to lipopolysaccharides exhibit conversion to activated fibroblasts. By means of endotoxin-induced endothelial fibrosis, endothelial cells downregulate the expression of endothelial proteins and express fibrotic and ECM markers throughout endothelial protein expression reprogramming. Although endotoxin-induced endothelial fibrosis should, in theory, be detrimental to endothelial vascular function, the role of endothelial fibrosis in sepsis syndrome or endotoxemia is not known. Therefore, we employed a rat model to investigate whether the inhibition of endotoxin-induced endothelial fibrosis protects against endotoxemia and whether this inhibition increases survival. Our results show that the inhibition of endotoxin-induced endothelial fibrosis reduced both hypotension and tachycardia. Endotoxemia-induced MODS was also decreased when endothelial fibrosis was inhibited; treated rats showed normal kidney and liver function, inhibition of muscle mass wasting and normal glycemia. Liver and kidney histology was preserved, and organ fibrosis and fibrotic protein expression were reduced. Furthermore, pro-inflammatory cytokine secretion and NOX-2-mediated oxidative stress bursts were decreased when endothelial fibrosis was inhibited. Remarkably, the risk of death associated with sepsis syndrome at early and late time points was decreased when endotoxemia-induced endothelial fibrosis was inhibited, and a significant increase in survival was observed. These results reveal a potential novel treatment strategy to protect against sepsis syndrome and endotoxemia.