Inflammatory response in microvascular endothelium in sepsis: role of oxidants

Blood pressure response index and clinical outcomes in patients with septic shock: a multicenter cohort study

BACKGROUND

Sepsis is a leading cause of mortality in intensive care units and vasoactive drugs are widely used in septic patients. The cardiovascular response of septic shock patients during resuscitation therapies and the relationship of the cardiovascular response and clinical outcome has not been clearly described.

METHODS

We included adult patients admitted to the ICU with sepsis from Peking Union Medical College Hospital (internal), Medical Information Mart for Intensive Care IV (MIMIC-IV) and eICU Collaborative Research Database (eICU-CRD). The Blood Pressure Response Index (BPRI) was defined as the ratio between the mean arterial pressure and the vasoactive-inotropic score. BRRI was compared with existing risk scores on predicting in-hospital death. The relationship between BPRI and in-hospital mortality was calculated. A XGBoost's machine learning model identified the features that influence short-term changes in BPRI.

FINDINGS

There were 2139, 9455, and 4202 patients in the internal, MIMIC-IV and eICU-CRD cohorts, respectively. BPRI had a better AUROC for predicting in-hospital mortality than SOFA (0.78 vs. 0.73, p = 0.01) and APS (0.78 vs. 0.74, p = 0.03) in the internal cohort. The estimated odds ratio for death per unit decrease in BPRI was 1.32 (95% CI 1.20-1.45) when BPRI was below 7.1 vs. 0.99 (95% CI 0.97-1.01) when BPRI was above 7.1 in the internal cohort; similar relationships were found in MIMIC-IV and eICU-CRD. Respiratory support and latest cumulative 12-h fluid balance were intervention-related features influencing BPRI.

INTERPRETATION

BPRI is an easy, rapid, precise indicator of the response of patients with septic shock to vasoactive drugs. It is a comparable and even better predictor of prognosis than SOFA and APS in sepsis and it is simpler and more convenient in use. The application of BPRI could help clinicians identify potentially at-risk patients and provide clues for treatment.

FUNDING

Fundings for the Beijing Municipal Natural Science Foundation; the National High Level Hospital Clinical Research Funding; the CAMS Innovation Fund for Medical Sciences (CIFMS) from Chinese Academy of Medical Sciences and the National Key R&D Program of China, Ministry of Science and Technology of the People's Republic of China.

Major endothelial damage markers identified from hemadsorption filters derived from treated patients with septic shock - endoplasmic reticulum stress and bikunin may play a role

Introduction

In septic patients the damage of the endothelial barrier is decisive leading to circulatory septic shock with disseminated vascular coagulation, edema and multiorgan failure. Hemadsorption therapy leads to rapid resolution of clinical symptoms. We propose that the isolation of proteins adsorbed to hemadsorption devices contributes to the identification of mediators responsible for endothelial barrier dysfunction.

Material and methods

Plasma materials enriched to hemadsorption filters (CytoSorb®) after therapy of patients in septic shock were fractionated and functionally characterized for their effect on cell integrity, viability, proliferation and ROS formation by human endothelial cells. Fractions were further studied for their contents of oxidized nucleic acids as well as peptides and proteins by mass spectrometry.

Results

Individual fractions exhibited a strong effect on endothelial cell viability, the endothelial layer morphology, and ROS formation. Fractions with high amounts of DNA and oxidized DNA correlated with ROS formation in the target endothelium. In addition, defined proteins such as defensins (HNP-1), SAA1, CXCL7, and the peptide bikunin were linked to the strongest additive effects in endothelial damage.

Conclusion

Our results indicate that hemadsorption is efficient to transiently remove strong endothelial damage mediators from the blood of patients with septic shock, which explains a rapid clinical improvement of inflammation and endothelial function. The current work indicates that a combination of stressors leads to the most detrimental effects. Oxidized ssDNA, likely derived from mitochondria, SAA1, the chemokine CXCL7 and the human neutrophil peptide alpha-defensin 1 (HNP-1) were unique for their significant negative effect on endothelial cell viability. However, the strongest damage effect occurred, when, bikunin - cleaved off from alpha-1-microglobulin was present in high relative amounts (>65%) of protein contents in the most active fraction. Thus, a relevant combination of stressors appears to be removed by hemadsorption therapy which results in fulminant and rapid, though only transient, clinical restitution.

Estimated Cerebral Perfusion Pressure and Intracranial Pressure in Septic Patients

BACKGROUND

Sepsis-associated brain dysfunction (SABD) is frequent and is associated with poor outcome. Changes in brain hemodynamics remain poorly described in this setting. The aim of this study was to investigate the alterations of cerebral perfusion pressure and intracranial pressure in a cohort of septic patients.

METHODS

We conducted a retrospective analysis of prospectively collected data in septic adults admitted to our intensive care unit (ICU). We included patients in whom transcranial Doppler recording performed within 48 h from diagnosis of sepsis was available. Exclusion criteria were intracranial disease, known vascular stenosis, cardiac arrhythmias, pacemaker, mechanical cardiac support, severe hypotension, and severe hypocapnia or hypercapnia. SABD was clinically diagnosed by the attending physician, anytime during the ICU stay. Estimated cerebral perfusion pressure (eCPP) and estimated intracranial pressure (eICP) were calculated from the blood flow velocity of the middle cerebral artery and invasive arterial pressure using a previously validated formula. Normal eCPP was defined as eCPP ≥ 60 mm Hg, low eCPP was defined as eCPP < 60 mm Hg; normal eICP was defined as eICP ≤ 20 mm Hg, and high eICP was defined as eICP > 20 mm Hg.

RESULTS

A total of 132 patients were included in the final analysis (71% male, median [interquartile range (IQR)] age was 64 [52-71] years, median [IQR] Acute Physiology and Chronic Health Evaluation II score on admission was 21 [15-28]). Sixty-nine (49%) patients developed SABD during the ICU stay, and 38 (29%) were dead at hospital discharge. Transcranial Doppler recording lasted 9 (IQR 7-12) min. Median (IQR) eCPP was 63 (58-71) mm Hg in the cohort; 44 of 132 (33%) patients had low eCPP. Median (IQR) eICP was 8 (4-13) mm Hg; five (4%) patients had high eICP. SABD occurrence and in-hospital mortality did not differ between patients with normal eCPP and patients with low eCPP or between patients with normal eICP and patients with high eICP. Eighty-six (65%) patients had normal eCPP and normal eICP, 41 (31%) patients had low eCPP and normal eICP, three (2%) patients had low eCPP and high eICP, and two (2%) patients had normal eCPP and high eICP; however, SABD occurrence and in-hospital mortality were not significantly different among these subgroups.

CONCLUSIONS

Brain hemodynamics, in particular CPP, were altered in one third of critically ill septic patients at a steady state of monitoring performed early during the course of sepsis. However, these alterations were equally common in patients who developed or did not develop SABD during the ICU stay and in patients with favorable or unfavorable outcome.

Identification of IL-8 in CSF as a potential biomarker in sepsis-associated encephalopathy

BACKGROUND

Sepsis-associated encephalopathy (SAE) is frequently present at the acute and chronic phase of sepsis, which is characterized by delirium, coma, and cognitive dysfunction. Despite the increased morbidity and mortality of SAE, the pathogenesis of SAE remains unclear. This study aims to discover the potential biomarkers, so as to clear the pathogenesis potentially contributing to the development of SAE and provide new therapeutic strategies for the treatment of SAE.

METHODS

The GSE135838 dataset was obtained from the Gene Expression Omnibus (GEO) database and utilized for analysis the differentially expressed genes (DEGs). The DEGs were analyzed by limma package of R language and the extracellular protein-differentially expressed genes (EP-DEGs) were screened by the Human Protein Atlas (HPA) and UniProt database. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were carried out to analyze the function and pathway of EP-DEGs. STRING, Cytoscape, MCODE and Cytohubba were used to construct a protein-protein interaction (PPI) network and screen key EP-DEGs. Key EP-DEGs levels were detected in the cerebrospinal fluid (CSF) of SAE patients and non-sepsis patients with critical illness. ROC curve was used to evaluate the diagnostic of SAE.

RESULTS

We screened 82 EP-DEGs from DEGs. EP-DEGs were enriched in cytokine-cytokine receptor interaction, IL-17 signaling pathway and NOD-like receptor signaling pathway. We identified 2 key extracellular proteins IL-1B and IL-8. We clinically verified that IL-6 and IL-8 levels were increased in CSF of SAE patients and CSF IL-8 (AUC = 0.882, 95 % CI = 0.775-0.988) had a higher accuracy in the diagnosis of SAE than CSF IL-6 (AUC = 0.824, 95 % CI = 0.686-0.961). Furthermore, we found that the IL-8 levels in CSF might not associated with Glasgow Coma Scale (GCS) scores of SAE patients.

CONCLUSION

IL-8 may be the key extracellular cytokine in the pathogenesis of SAE. Bioinformatics methods were used to explore the biomarkers of SAE and validated the results in clinical samples. Our findings indicate that the IL-8 in CSF might be the potential diagnostic biomarker and therapeutic target in SAE.

Exosome-Based Mitochondrial Delivery of circRNA mSCAR Alleviates Sepsis by Orchestrating Macrophage Activation

Sepsis is one of the most common causes of death, which is closely related to the uncontrolled systemic inflammation. Dysregulation of M1 macrophage polarization is the primary contributor to serious inflammation. In this study, it is revealed that the murine homologue of circRNA SCAR (steatohepatitis-associated circRNA ATP5B regulator), denoted as circRNA mSCAR hereafter, decreases in the macrophages of septic mice, which correlates with the excessive M1 polarization. To restore circRNA mSCAR in mitochondria, exosomes encapsulated with circRNA mSCAR are further electroporated with poly-D-lysine-graft-triphenylphosphine (TPP-PDL), and thus TPP-PDL facilitates the bound circRNA delivered into mitochondria when the exosomes engulf by the recipient cells. In in vivo septic mouse model and in vitro cell model, it is shown that the exosome-based mitochondria delivery system delivers circRNA mSCAR into mitochondria preferentially in the macrophages, favoring macrophage polarization toward M2 subtype. Accordingly, the systemic inflammation is attenuated by exosome-based mitochondrial delivery of circRNA mSCAR, together with alleviated mortality. Collectively, the results uncover the critical role of circRNA mSCAR in sepsis, and provide a promising approach to attenuate sepsis via exosome-based mitochondrial delivery of circRNA mSCAR.

The biological alterations of synapse/synapse formation in sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a common complication caused by sepsis, and is responsible for increased mortality and poor outcomes in septic patients. Neurological dysfunction is one of the main manifestations of SAE patients. Patients may still have long-term cognitive impairment after hospital discharge, and the underlying mechanism is still unclear. Here, we first outline the pathophysiological changes of SAE, including neuroinflammation, glial activation, and blood-brain barrier (BBB) breakdown. Synapse dysfunction is one of the main contributors leading to neurological impairment. Therefore, we summarized SAE-induced synaptic dysfunction, such as synaptic plasticity inhibition, neurotransmitter imbalance, and synapses loss. Finally, we discuss the alterations in the synapse, synapse formation, and mediators associated with synapse formation during SAE. In this review, we focus on the changes in synapse/synapse formation caused by SAE, which can further understand the synaptic dysfunction associated with neurological impairment in SAE and provide important insights for exploring appropriate therapeutic targets of SAE.

[Elucidation and Application of Novel Action of Therapeutic Agents for Diabetic Neuropathy]

Epalrestat is the only aldose reductase inhibitor that is currently available for diabetic peripheral neuropathy. Oxidative stress impairs endothelial cells, thereby leading to numerous pathological conditions. Increasing antioxidative ability is important to prevent cellular toxicity induced by reactive oxygen species. Epalrestat increases antioxidant defense factors such as glutathione and γ-glutamylcysteine ligase in vascular endothelial cells through activation of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). This increases suppression of oxidative stress-induced cellular toxicity. Cadmium is an industrial and environmental pollutant that targets the vascular endothelium. The vascular system is critically affected by cadmium toxicity. Therapeutic treatment against cadmium toxicity is chelation therapy that promotes metal excretion; however, cadmium chelators can cause renal toxicity. Therefore, safe and efficient therapeutic agents are required. Epalrestat suppresses cadmium-induced cytotoxicity in vascular endothelial cells through activation of Nrf2. In addition, epalrestat affects the intracellular levels of cadmium, cadmium transporter Zrt-Irt-like protein 8 (ZIP8), and metallothionein (MT). The upregulation of ZIP8 and MT may be involved in the suppression of cadmium-induced cytotoxicity by epalrestat. Drug repurposing is a new strategy for drug discovery in which the pharmacological action of existing medicines whose safety and pharmacokinetics have already been confirmed clinically and whose use has been approved is examined comprehensively at the molecular level. The results can be applied to the development of existing drugs for use as medicines for the treatment of other diseases. This review provides useful findings for future expansion of indications as research leading to drug repurposing of epalrestat.

Lysine specific demethylase 1 inhibitor alleviated lipopolysaccharide/D-galactosamine-induced acute liver injury

Acute liver injury is a severe clinical syndrome with markedly high mortality and poor prognosis. An accumulating body of evidence has demonstrated that epigenetic mechanisms have essential roles in the pathogenesis of acute liver injury. Lysine-specific demethylase 1 (LSD1) belongs to the amine oxidase superfamily of flavin adenine dinucleotide (FAD)-dependent enzymes, specifically demethylates H3 lysine 4. In the study, we investigated the effects and mechanisms of LSD1 in lipopolysaccharide (LPS)/D-Galactosamine (D-Gal)-induced acute liver injury in mice. Western blot analysis showed that LSD1 phosphorylation and di-methylated histone H3 on lysine 4 (H3K4me2) protein expression were significantly increased after LPS/D-Gal treatment (2.3 and 2.4 times higher than control respectively). GSK-LSD1 2HCl is an irreversible and selective LSD1 inhibitor. Pre-treatment with LSD1 inhibitor alleviated LPS/D-Gal-induced liver damage, decreased serum levels of alanine transaminase and aspartate aminotransferase in mice. Moreover, the LSD1 phosphorylation level in low, medium, and high LSD1 inhibitor groups was lower by a factor of 1.6, 1.9, and 2.0 from the LPS/D-Gal group, respectively. Mechanistically, LSD1 inhibitor further inhibited NF-κB signaling cascades and subsequently inhibited the production of pro-inflammatory cytokine TNF-α, IL-6, and IL-1β induced by LPS/D-Gal in liver tissues. Furthermore, LSD1 inhibitor upregulated the protein expression of Nrf2/HO-1 signaling pathways, and the activities of related antioxidant enzymes were enhanced. Collectively, our data demonstrated that LSD1 inhibitor protected against the LPS/D-Gal-induced acute liver injury via inhibiting inflammation and oxidative stress, and targeting the epigenetic marker may be a potent therapeutic strategy for acute liver injury.

Multiple subregions within the caveolin-1 scaffolding domain inhibit fibrosis, microvascular leakage, and monocyte migration

The caveolin-1 scaffolding domain (CSD, amino acids 82-101 of caveolin-1) has been shown to suppress bleomycin-induced lung and skin fibrosis and angiotensin II (AngII)-induced myocardial fibrosis. To identify active subregions within CSD, we split its sequence into three slightly overlapping 8-amino acid subregions (82-89, 88-95, and 94-101). Interestingly, all three peptides showed activity. In bleomycin-treated mice, all three subregions suppressed the pathological effects on lung and skin tissue morphology. In addition, while bone marrow monocytes isolated from bleomycin-treated mice showed greatly enhanced migration in vitro toward CXCL12, treatment in vivo with CSD and its subregions almost completely suppressed this enhanced migration. In AngII-induced heart failure, both 82-89 and 88-95 significantly suppressed fibrosis (both Col I and HSP47 levels), microvascular leakage, and heart weight/ body weight ratio (HW/BW) while improving ventricular function. In contrast, while 94-101 suppressed the increase in Col I, it did not improve the other parameters. The idea that all three subregions can be active depending on the assay was further supported by experiments studying the in vitro migration of human monocytes in which all three subregions were extremely active. These studies are very novel in that it has been suggested that there is only one active region within CSD that is centered on amino acids 90-92. In contrast, we demonstrate here the presence of other active regions within CSD.

E. coli strain-dependent lipid alterations in cocultures with endothelial cells and neutrophils modeling sepsis

Dysregulated lipid metabolism is common in infection and inflammation and is a part of the complex milieu underlying the pathophysiological sequelae of disease. Sepsis is a major cause of mortality and morbidity in the world and is characterized by an exaggerated host response to an infection. Metabolic changes, including alterations in lipid metabolism, likely are important in sepsis pathophysiology. Here, we designed an in vitro cell culture model using endothelial cells, E. coli, and neutrophils to mimic sepsis in a simplified cell model. Lipid alterations were studied in the presence of the pathogenic E. coli strain CFT073 and non-pathogenic E. coli strain JM109. We employed untargeted lipidomics to first identify lipid changes and then targeted lipidomics to confirm changes. Both unique and shared lipid signatures were identified in cocultures with these E. coli strains. In the absence of neutrophils, the CFT073 strain elicited alterations in lysophosphatidylcholine and diglyceride molecular species during coculture while both strains led to increases in phosphatidylglycerols. Lipid alterations in these cocultures changed with the addition of neutrophils. In the presence of neutrophils with E. coli and endothelial cells, triglyceride increases were a unique response to the CFT073 strain while phosphatidylglycerol and diglyceride increases occurred in response to both strains. Phosphatidylethanolamine also increased in neutrophils, E. coli and endothelial cells cocultures, and this response was greater in the presence of the CFT073 strain. We further evaluated changes in phosphatidylethanolamine in a rat model of sepsis, which showed multiple plasma phosphatidylethanolamine molecular species were elevated shortly after the induction of sepsis. Collectively, these findings demonstrate unique lipid responses by co-cultures of E. coli with endothelial cells which are dependent on the E. coli strain as well as the presence of neutrophils. Furthermore, increases in phosphatidylethanolamine levels in CFT073 urosepsis E. coli, endothelial cell, neutrophil cocultures were similarly observed in the plasma of septic rats.

Infectious disease-associated encephalopathies

Infectious diseases may affect brain function and cause encephalopathy even when the pathogen does not directly infect the central nervous system, known as infectious disease-associated encephalopathy. The systemic inflammatory process may result in neuroinflammation, with glial cell activation and increased levels of cytokines, reduced neurotrophic factors, blood-brain barrier dysfunction, neurotransmitter metabolism imbalances, and neurotoxicity, and behavioral and cognitive impairments often occur in the late course. Even though infectious disease-associated encephalopathies may cause devastating neurologic and cognitive deficits, the concept of infectious disease-associated encephalopathies is still under-investigated; knowledge of the underlying mechanisms, which may be distinct from those of encephalopathies of non-infectious cause, is still limited. In this review, we focus on the pathophysiology of encephalopathies associated with peripheral (sepsis, malaria, influenza, and COVID-19), emerging therapeutic strategies, and the role of neuroinflammation.

Effect of Lipopolysaccharide and TNFα on Neuronal Ascorbic Acid Uptake

Vitamin C (ascorbic acid: AA) uptake in neurons occurs via the sodium-dependent vitamin C transporter-2 (SVCT2), which is highly expressed in the central nervous system (CNS). During chronic neuroinflammation or infection, CNS levels of lipopolysaccharide (LPS) and LPS-induced tumor necrosis factor-α (TNFα) are increased. Elevated levels of LPS and TNFα have been associated with neurodegenerative diseases together with reduced levels of AA. However, little is known about the impacts of LPS and TNFα on neuronal AA uptake. The objective of this study was to examine the effect of LPS and TNFα on SVCT2 expression and function using in vitro and in vivo approaches. Treatment of SH-SY5Y cells with either LPS or TNFα inhibited AA uptake. This reduced uptake was associated with a significant decrease in SVCT2 protein and mRNA levels. In vivo exposure to LPS or TNFα also decreased SVCT2 protein and mRNA levels in mouse brains. Both LPS and TNFα decreased SLC23A2 promoter activity. Further, the inhibitory effect of LPS on a minimal SLC23A2 promoter was attenuated when either the binding site for the transcription factor Sp1 was mutated or cells were treated with the NF-κB inhibitor, celastrol. We conclude that inflammatory signals suppress AA uptake by impairing SLC23A2 transcription through opposing regulation of Sp1 and NF-κB factors.

L-Threoascorbic acid treatment promotes S. aureus-infected primary human endothelial cells survival and function, as well as intracellular bacterial killing, and immunomodulates the release of IL-1β and soluble ICAM-1

BACKGROUND

Vitamin C (ascorbic acid, AscH2) has been shown to enhance immunity. Here, we studied its immunomodulatory effect on human endothelial cells (ECs) during S. aureus infection.

MATERIALS AND METHODS

The ex vivo effects of AscH2 were performed on primary human umbilical vein endothelial cells (HUVECs) infected or not with S. aureus.

RESULTS

AscH2 treatment induced a marked downregulation of nitric oxide (NO) production and a moderate upregulation of arginase activity in S. aureus-infected HUVECs (respectively, p < 0.05 and p > 0.05). Although the upregulated release levels of soluble intercellular adhesion molecular 1 (sICAM-1/sCD54) and sE-selectin (sCD62E) molecules were not significantly different between treated and untreated S. aureus-infected HUVECs, AscH2 treatment induced reversing effect on sICAM-1 release when comparing to uninfected control HUVECs. Moreover, AscH2 treatment appears to have a significant effect on preventing HUVEC necrosis induced by S. aureus infection (p < 0.05). Furthermore, AscH2 treatment induced a significant upregulation of cell protective redox biomarker in S. aureus-infected, as shown by superoxide dismutase (SOD) activity (p < 0.05), but not by catalase activity (p > 0.05). Additionally, S. aureus infection markedly downregulated total bound calcium ions (_bCa²⁺) levels as compared to control HUVECs, whereas, AscH2 treatment induced a slight upregulation of _bCa²⁺ levels in infected HUVECs as compared to infected and untreated HUVECs (p > 0.05). On the other hand, AscH2 treatment downregulated increased total cellular cholesterol content (_tccCHOL) levels in HUVECs induced by S. aureus infection (p < 0.05). In addition, AscH2 treatment markedly reversed S. aureus effect on upregulation of intracellular glucose (_iGLU) levels within infected HUVECs (p < 0.05). Moreover, AscH2 treatment significantly downregulated S. aureus growth (p < 0.05), and significantly upregulated bacterial internalization and intracellular killing by HUVECs (p < 0.05), as well as their cell cycle activation (p < 0.01). Finally, AscH2 treatment has a slight effect on the production of interleukin 6 (IL-6), but induced a marked downregulation of that of IL-1β in S. aureus-infected HUVECs (respectively, p > 0.05, and p < 0.05).

CONCLUSIONS

Our outcomes demonstrated that, during S. aureus infection, AscH2 treatment promotes human ECs survival and function, as well as prevents inflammatory response exacerbation, while inducing bactericidal activity.

Sepsis-Associated Brain Dysfunction: A Review of Current Literature

Sepsis-associated brain dysfunction (SABD) may be the most common type of encephalopathy in critically ill patients. SABD develops in up to 70% of septic patients and represents the most frequent organ insufficiency associated with sepsis. It presents with a plethora of acute neurological features and may have several serious long-term psychiatric consequences. SABD might cause various pathological changes in the brain through numerous mechanisms. Clinical neurological examination is the basic screening method for SABD, although it may be challenging in subjects receiving with opioids and sedative agents. As electrographic seizures and periodic discharges might be present in 20% of septic patients, screening with electroencephalography (EEG) might be useful. Several imaging techniques have been suggested for non-invasive assessment of structure and function of the brain in SABD patients; however, their usefulness is rather limited. Although several experimental therapies have been postulated, at the moment, no specific treatment exists. Clinicians should focus on preventive measures and optimal management of sepsis. This review discusses epidemiology, clinical presentation, pathology, pathophysiology, diagnosis, management, and prevention of SABD.

Insulin therapy for hyperglycemia in neonatal sepsis using a preterm mouse model

BACKGROUND

Stress-induced hyperglycemia is a frequent complication of neonatal sepsis. Hyperglycemia induces oxidative stress and immunosuppression. We investigated the glucose kinetics and effect of insulin administration during stress-induced hyperglycemia in a neonatal sepsis mouse model.

METHODS

A stock cecal slurry (CS) solution was prepared from adult cecums and 3.0 mg of CS/g (LD₄₀ ) was administered intraperitoneally to 4-day-old FVB mouse pups. Blood glucose levels were measured at 1.5, 3, 6, and 9 h post-sepsis induction and compared with basal levels. Two different doses of ultrafast-acting insulin were administered subcutaneously, and blood glucose levels and survival rates were monitored.

RESULTS

Blood glucose levels were significantly higher than those of baseline levels with a peak at 3 h, which progressively decreased from 6 to 9 h post-sepsis induction. Insulin treatment reduced post-sepsis-induced hyperglycemia at 1.5 and 3 h. The mortality rate of CS-only pups (39%) was similar to that of CS + 1 U/kg insulin pups (60%). However, the mortality rate of CS + 5 U/kg insulin pups (82%) was significantly higher than that of CS-only pups.

CONCLUSIONS

Marked hyperglycemia was induced immediately after post-sepsis induction, and the high-dose insulin treatment increased mortality post-induction. Stress-induced hyperglycemia could therefore be a physiological and protective response for preterm sepsis, and aggressive treatment of this hyperglycemia might be contraindicated.

High expression of long non-coding RNA MALAT1 correlates with raised acute respiratory distress syndrome risk, disease severity, and increased mortality in sepstic patients

This study aimed to explore the correlation of long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) expression with acute respiratory distress syndrome (ARDS) risk, disease severity, inflammation level, and mortality in septic patients. 152 septic patients were consecutively included and surveillance was conducted daily to identify ARDS occurrence. Severity and organ failure of sepsis were assessed by APACHE II score and SOFA score respectively, and the in-hospital mortality was calculated. Patients' blood samples were extracted. Lnc-MALAT1 expression and inflammatory cytokines levels were detected using real-time qPCR and ELISA assay respectively. The incidence of ARDS was 27.0%. Lnc-MALAT1 expression was increased in ARDS patients compared to non-ARDS patients, and it could distinguish ARDS from non-ARDS by ROC with AUC of 0.674 (95% CI: 0.581-0.766). Multivariate logistic regression analysis displayed that lnc-MALAT1 high expression, increased age, higher proportion of smoking and COPD were independent factors for predicting elevated ARDS risk. Lnc-MALAT1 expression was positively correlated with APACHE II score, SOFA score, and inflammatory factors levels including C-reactive protein, procalcitonin, TNF-α, IL-1β, IL-6 and IL-17. Furthermore, the mortality was 30.9%, and lnc-MALAT1 expression was elevated in non-survivors compared to survivors, presenting a good predictive value for high mortality by ROC with AUC of 0.651 (95% CI: 0.555-0.747). Lnc-MALAT1 high expression predicts increased ARDS risk, and correlates with severe disease condition and raised mortality in sepsis patients.

Challenge to the Intestinal Mucosa During Sepsis

Sepsis is a complex of life-threating organ dysfunction in critically ill patients, with a primary infectious cause or through secondary infection of damaged tissues. The systemic consequences of sepsis have been intensively examined and evidences of local alterations and repercussions in the intestinal mucosal compartment is gradually defining gut-associated changes during sepsis. In the present review, we focus on sepsis-induced dysfunction of the intestinal barrier, consisting of an increased permeability of the epithelial lining, which may facilitate bacterial translocation. We discuss disturbances in intestinal vascular tonus and perfusion and coagulopathies with respect to their proposed underlying molecular mechanisms. The consequences of enzymatic responses by pancreatic proteases, intestinal alkaline phosphatases, and several matrix metalloproteases are also described. We conclude our insight with a discussion on novel therapeutic interventions derived from crucial aspects of the gut mucosal dynamics during sepsis.

The phenotype of vascular smooth muscle cells co-cultured with endothelial cells is modulated by PDGFR-β/IQGAP1 signaling in LPS-induced intravascular injury

Background Sepsis, a leading cause of death in intensive care units, is generally associated with vascular dysfunction. However, its pathophysiological process has not been fully clarified, lacking in-depth knowledge of its pathophysiological process may hinder the improvement of diagnosis and therapy for sepsis. Hence, as the key parts of the vascular wall, the interaction between endothelial cells (ECs) and smooth muscle cells (SMCs) under septic situation need to be further studied. Methods ECs and SMCs were co-cultured using Transwell plates. Lipopolysaccharide (LPS) was used to induce sepsis. A scratch-wound assay was used to assess cell migration, and western blotting was used to assess the level of redifferentiation of SMCs as well as the expression of PDGFR-β and IQGAP1. Results Co-culture with ECs reduced the redifferentiation of SMCs induced by LPS (10 μg/ml), which was characterized by increased migration ability and decreased expression of contractile proteins (e.g., SM22 and α-SMA). The production of TNF-α could decrease the level of PDGFR-β in SMCs. Treatment of SMCs with the PDGFR-β inhibitor imatinib (5 μM) was able to counteract LPS-induced SMC redifferentiation and reduce IQGAP1 protein expression, especially when SMCs were co-cultured with ECs. Conclusion The phenotype of vascular SMCs co-cultured with ECs was modulated by IQGAP1 through the PDGFR-β pathway, which may lead to vascular remodeling and homeostasis in LPS-induced intravascular injury. This pathway could be a novel target for the treatment of vascular damage.

Inflammasomes: Pandora's box for sepsis

Sepsis was known to ancient Greeks since the time of great physician Hippocrates (460-377 BC) without exact information regarding its pathogenesis. With time and medical advances, it is now considered as a condition associated with organ dysfunction occurring in the presence of systemic infection as a result of dysregulation of the immune response. Still with this advancement, we are struggling for the development of target-based therapeutic approach for the management of sepsis. The advancement in understanding the immune system and its working has led to novel discoveries in the last 50 years, including different pattern recognition receptors. Inflammasomes are also part of these novel discoveries in the field of immunology which are <20 years old in terms of their first identification. They serve as important cytosolic pattern recognition receptors required for recognizing cytosolic pathogens, and their pathogen-associated molecular patterns play an important role in the pathogenesis of sepsis. The activation of both canonical and non-canonical inflammasome signaling pathways is involved in mounting a proinflammatory immune response via regulating the generation of IL-1β, IL-18, IL-33 cytokines and pyroptosis. In addition to pathogens and their pathogen-associated molecular patterns, death/damage-associated molecular patterns and other proinflammatory molecules involved in the pathogenesis of sepsis affect inflammasomes and vice versa. Thus, the present review is mainly focused on the inflammasomes, their role in the regulation of immune response associated with sepsis, and their targeting as a novel therapeutic approach.

Exogenous Heat Shock Cognate Protein 70 Suppresses LPS-Induced Inflammation by Down-Regulating NF-κB through MAPK and MMP-2/-9 Pathways in Macrophages

Heat shock cognate protein 70 (HSC70), a molecular chaperone, is constitutively expressed by mammalian cells to regulate various cellular functions. It is associated with many diseases and is a potential therapeutic target. Although HSC70 also possesses an anti-inflammatory action, the mechanism of this action remains unclear. This current study aimed to assess the anti-inflammatory effects of HSC70 in murine macrophages RAW 264.7 exposed to lipopolysaccharides (LPS) and to explain its pathways. Mouse macrophages (RAW 264.7) in 0.1 µg/mL LPS incubation were pretreated with recombinant HSC70 (rHSC70) and different assays (Griess assay, enzyme-linked immune assay/ELISA, electrophoretic mobility shift assay/EMSA, gelatin zymography, and Western blotting) were performed to determine whether rHSC70 blocks pro-inflammatory mediators. The findings showed that rHSC70 attenuated the nitric oxide (NO) generation, tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6) expressions in LPS-stimulated RAW264.7 cells. In addition, rHSC70 preconditioning suppressed the activities and expressions of matrix metalloproteinase-2 (MMP-2) and MMP-9. Finally, rHSC70 diminished the nuclear translocation of nuclear factor-κB (NF-κB) and reduced the phosphorylation of extracellular-signal regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinases (MAPK), and phosphatidylinositol-3-kinase (PI3K/Akt). We demonstrate that rHSC70 preconditioning exerts its anti-inflammatory effects through NO production constriction; TNF-α, and IL-6 suppression following down-regulation of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), and MMP-2/MMP-9. Accordingly, it ameliorated the signal transduction of MAPKs, Akt/IκBα, and NF-κB pathways. Therefore, extracellular HSC70 plays a critical role in the innate immunity modulation and mechanisms of endogenous protective stimulation.

Evaluation of oxidative stress and antioxidant status: Correlation with the severity of sepsis

Sepsis is a condition caused by infection followed by unregulated inflammatory response which may lead to the organ dysfunction. During such condition, over-production of oxidants is one of the factors which contribute cellular toxicity and ultimately organ failure and mortality. Antioxidants having free radicals scavenging activity exert protective role in various diseases. This study has been designed to evaluate the levels of oxidative and antioxidative activity in sepsis patients and their correlation with the severity of the sepsis. A total of 100 sepsis patients and 50 healthy controls subjects were enrolled in this study from the period October 2016 to June 2017. The investigation included measurements of oxidative enzyme, myeloperoxidase (MPO), antioxidant enzymes including superoxide dismutase activity (SOD) and catalase activity (CAT) and cytokines (TNF-α, IL-8 and IFN-γ). Furthermore, the level of these activities was correlated with severity of sepsis. Augmented levels of oxidants were found in sepsis as demonstrated by DMPO nitrone adduct formation and plasma MPO level activity (1.37 ± 0.51 in sepsis vs 0.405 ± 0.16 in control subjects). Cytokines were also found to be increased in sepsis patients. However, plasma SOD and CAT activities were significantly attenuated (P < .001) in the sepsis patients compared with controls subjects. Moreover, inverse relation between antioxidant enzymes (SOD and CAT) and organ failure assessment (SOFA), physiological score (APACHE II), organ toxicity specific markers have been observed as demonstrated by Pearson's correlation coefficient. This study suggests that imbalance between oxidant and antioxidant plays key role in the severity of sepsis.

Septic-Induced microRNA Expression Modulations Are Linked to Angiogenesis, Vasomotion, and Hypoxia-Induced Processes

Sepsis is an exaggerated immune reaction to an infection, which leads to organ dysfunction especially circulatory failure. This is based on cellular processes, which are regulated by post-transcriptional gene expression modulations including microRNAs (miRNAs). In order to elucidate the role miRNAs play in septic processes, monocytes and endothelial cells were grown in an inflammatory milieu. In addition, aortas from septic mice were investigated. Expression of miRNAs was analysed by both next generation sequencing (NGS) and NanoString technology, and miRNA targets were identified by in silico analysis. Clear alterations in miRNA expression profiles were found in monocytes, endothelial cells, and aortas exposed to septic conditions compared to the respective control. In silico analysis revealed several of the differentially expressed miRNAs to be involved in cellular response to hypoxia. In endothelial cells, for instance, miR-21-5p and miR-106b-5p emerged, which are known to interact with hypoxia inducible factor 1 alpha (HIF-1α), a major player in the process of angiogenesis. In line with this, in aortas expression changes were observed for miR-144-3p, which targets HIF-1α as well. Further validated target genes of differentially expressed miRNAs encompass the vascular endothelial growth factor receptor 1 (VEGFR1) and the vascular endothelial growth factor A (VEGFA), which represent essential mediators of angiogenesis. Moreover, several miRNAs impacting on genes encoding mediators of vasomotion were identified to be altered in their expression profiles in context of an inflammatory milieu. Altogether, the data indicate that miRNAs are an interesting starting point for functional and mechanistic sepsis research.

2,3,5,4'‑Tetrahydroxystilbene‑2‑O‑β‑D‑glucoside inhibits septic serum‑induced inflammatory injury via interfering with the ROS‑MAPK‑NF‑κB signaling pathway in pulmonary aortic endothelial cells

Sepsis is characterized by injury to the microvasculature and the microvascular endothelial cells, leading to barrier dysfunction. However, the specific role of injury in septic endothelial barrier dysfunction remains to be elucidated. In the present study, it was hypothesized that endothelial cell inflammatory injury is likely required for barrier dysfunction under septic conditions in vitro. 2,3,5,4'‑Tetrahydroxystilbene‑2‑O‑β‑D‑glucoside (TSG), a compound extracted from Chinese herbs, is able to inhibit the inflammatory injury of septic‑serum in endothelial cells. In the present study, cell viability was assayed by CCK‑8 method; mRNA and protein expression was identified by RT‑qPCR, western blot or Elisa, respectively and the production of reactive oxygen species was observed by a fluorescence microscope. The present study indicated that septic serum significantly decreased the cell viability of pulmonary aortic endothelial cells (PAECs) following co‑cultivation for 6 h, which occurred in a time‑dependent manner. TSG notably increased the viability of PAECs in a time‑ and concentration‑dependent manner. Further investigations revealed that septic serum increased the secretion of interleukin (IL)‑1β, IL‑6 and C‑reactive protein in PAECs, whereas pretreatment with TSG significantly decreased the secretion of these inflammatory factors. These data indicated that septic serum increased inflammatory injury to the PAECs, and TSG decreased this injury via the reactive oxygen species‑mitogen‑activated protein kinase‑nuclear factor‑κB signaling pathway.

Impact of Unsaturated Fatty Acids on Cytokine-Driven Endothelial Cell Dysfunction

Polyunsaturated fatty acids (PUFA) are reported to exert prophylactic and acute therapeutic effects in diseases linked to endothelial dysfunction. In the present study, the consequences of a PUFA enrichment of endothelial cells (cell line TIME) on cell viability, expression of the cytokines interleukin-6 (IL-6), interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF), and monocyte chemoattractant protein 1 (MCP-1), synthesis of the adhesion molecules intercellular adhesion molecule 1 (ICAM-1) and vascular adhesion molecule 1 (VCAM-1), and production of the coagulation factors plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF), and tissue factor (TF) was analyzed in parallel. PUFA of both the n3 and the n6 family were investigated in a physiologically relevant concentration of 15 µM, and experiments were performed in both the presence and the absence of the pro-inflammatory cytokines interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). Supplementation of the culture medium with particular fatty acids was found to have a promoting effect on cellular production of the cytokines IL-6, IL-8, GM-CSF, and MCP-1. Further on, PUFA treatment in the absence of a stimulant diminished the percentage of endothelial cells positive for ICAM-1, and adversely affected the stimulation-induced upregulation of VCAM-1. Cell viability and production of coagulation factors were not or only marginally affected by supplemented fatty acids. Altogether, the data indicate that PUFA of either family are only partially able to counterbalance the destructive consequences of an endothelial dysfunction.

Myeloperoxidase-derived 2-chlorofatty acids contribute to human sepsis mortality via acute respiratory distress syndrome

Sepsis-associated acute respiratory distress syndrome (ARDS) is characterized by neutrophilic inflammation and poor survival. Since neutrophil myeloperoxidase (MPO) activity leads to increased plasma 2-chlorofatty acid (2-ClFA) levels, we hypothesized that plasma concentrations of 2-ClFAs would associate with ARDS and mortality in subjects with sepsis. In sequential consenting patients with sepsis, free 2-ClFA levels were significantly associated with ARDS, and with 30-day mortality, for each log increase in free 2-chlorostearic acid. Plasma MPO was not associated with either ARDS or 30-day mortality but was correlated with 2-ClFA levels. Addition of plasma 2-ClFA levels to the APACHE III score improved prediction for ARDS. Plasma 2-ClFA levels correlated with plasma levels of angiopoietin-2, E selectin, and soluble thrombomodulin. Endothelial cells treated with 2-ClFA responded with increased adhesion molecule surface expression, increased angiopoietin-2 release, and dose-dependent endothelial permeability. Our results suggest that 2-ClFAs derived from neutrophil MPO-catalyzed oxidation contribute to pulmonary endothelial injury and have prognostic utility in sepsis-associated ARDS.

Inhibition of intestinal ascorbic acid uptake by lipopolysaccharide is mediated via transcriptional mechanisms

Ascorbic acid (AA) accumulation in intestinal epithelial cells is an active transport process mainly mediated by two sodium-dependent vitamin C transporters (SVCT-1 and SVCT-2). To date, little is known about the effect of gut microbiota generated lipopolysaccharide (LPS) on intestinal absorption of water-soluble vitamins. Therefore, the objective of this study was to investigate the effects of bacterially-derived LPS on AA homeostasis in enterocytes using Caco-2 cells, mouse intestine and intestinal enteroids models. Pre-treating Caco-2 cells and mice with LPS led to a significant decrease in carrier-mediated AA uptake. This inhibition was associated with a significant reduction in SVCT-1 and SVCT-2 protein, mRNA, and hnRNA expression. Furthermore, pre-treating enteroids with LPS also led to a marked decrease in SVCT-1 and SVCT-2 protein and mRNA expression. Inhibition of SVCT-1 and SVCT-2 occurred at least in part at the transcriptional level as promoter activity of SLC23A1 and SLC23A2 was attenuated following LPS treatment. Subsequently, we examined the protein and mRNA expression levels of HNF1α and Sp1 transcription factors, which are needed for basal SLC23A1 and SLC23A2 promoter activity, and found that they were significantly decreased in the LPS treated Caco-2 cells and mouse jejunum; this was reflected on level of the observed reduction in the interaction of these transcription factors with their respective promoters in Caco-2 cells treated with LPS. Our findings indicate that LPS inhibits intestinal carrier- mediated AA uptake by down regulating the expression of both vitamin C transporters and transcriptional regulation of SLC23A1 and SLC23A2 genes.

W Spring for Management of Impacted Teeth

Forced eruption of an impacted tooth necessitates a firm and versatile attachment for force application. The present article describes a simple modification of NiTi closed coil spring called W spring for predictable forced eruption of impacted teeth.

Intravenous Arginine Administration Promotes Proangiogenic Cells Mobilization and Attenuates Lung Injury in Mice with Polymicrobial Sepsis

This study investigated the influence of intravenous arginine (Arg) administration on alteration of circulating proangiogenic cells and remote lung injury in a model of polymicrobial sepsis. Mice were assigned to one normal control group (NC) and two sepsis groups that were induced by cecal ligation and puncture (CLP). One of the sepsis groups was injected with saline (SS), whereas the other (SA) was administered with a single bolus of 300 mg Arg/kg body weight via the tail vein 1 h after CLP. Septic mice were sacrificed at either 24 or 48 h after CLP, with their blood and lung tissues collected for analysis. Results showed that septic groups had higher proangiogenic cells releasing factors and proangiogenic cells percentage in blood. Also, concentration of inflammatory cytokines and expression of angiopoietin (Angpt)/Tie-2 genes in lung tissues were upregulated. Arg administration promoted mobilization of circulating proangiogenic cells while it downregulated the production of inflammatory cytokines and expression of Angpt/Tie-2 genes in the lung. The results of this investigation suggested that intravenous administration of Arg shortly after the onset of sepsis enhanced the mobilization of circulating proangiogenic cells, maintained the homeostasis of the Angpt/Tie-2 axis, and attenuated remote organ injury in polymicrobial sepsis.

Grape seed proanthocyanidin extract protects lymphocytes against histone-induced apoptosis

Apoptosis of lymphocytes is associated with immunosuppression and poor prognosis in sepsis. Our previous report showed that histones, nuclear proteins released from damaged or dying cells in sepsis, can mediate lymphocyte apoptosis via mitochondria damage. Grape seed proanthocyanidin extract (GSPE), a natural substance with protective properties against oxidative stress, plays a vital role in cell and mitochondria protection. We thus hypothesized that GSPE may play a protective role in histone-induced lymphocyte apoptosis through its anti-oxidative properties. In this study, we investigated the protective efficacy of GSPE on lymphocyte apoptosis induced by extracellular histones, a main contributor of death in sepsis. Human blood lymphocytes were treated with 50 μg/ml histones, 2 μg/ml GSPE, or a combination of both. A total of 100 μM N-acetylcysteine (NAC), a reactive oxygen species (ROS) inhibitor, was used as a positive control for GSPE. Apoptosis, intracellular ROS levels, mitochondrial membrane potential, Bcl-2 expression, and caspase-3 cleavage were measured. Our data clearly indicate that GSPE significantly inhibited lymphocyte apoptosis, generation of ROS, the loss of mitochondrial membrane potential, the decrease in Bcl-2 expression, and caspase-3 activation induced by extracellular histones. In conclusion, we show that GSPE has a protective effect on lymphocyte apoptosis induced by extracellular histones. This study suggests GSPE as a potential therapeutic agent that could help reduce lymphocyte apoptosis, and thus the state of immunosuppression was observed in septic patients.

The Glyoxalase System and Methylglyoxal-Derived Carbonyl Stress in Sepsis: Glycotoxic Aspects of Sepsis Pathophysiology

Sepsis remains one of the leading causes of death in intensive care units. Although sepsis is caused by a viral, fungal or bacterial infection, it is the dysregulated generalized host response that ultimately leads to severe dysfunction of multiple organs and death. The concomitant profound metabolic changes are characterized by hyperglycemia, insulin resistance, and profound transformations of the intracellular energy supply in both peripheral and immune cells. A further hallmark of the early phases of sepsis is a massive formation of reactive oxygen (ROS; e.g., superoxide) as well as nitrogen (RNS; e.g., nitric oxide) species. Reactive carbonyl species (RCS) form a third crucial group of highly reactive metabolites, which until today have been not the focus of interest in sepsis. However, we previously showed in a prospective observational clinical trial that patients suffering from septic shock are characterized by significant methylglyoxal (MG)-derived carbonyl stress, with the glyoxalase system being downregulated in peripheral blood mononuclear cells. In this review, we give a detailed insight into the current state of research regarding the metabolic changes that entail an increased MG-production in septicemia. Thus, we point out the special role of the glyoxalase system in the context of sepsis.

Hemodynamic coherence in sepsis

Microvascular alterations are a hallmark of sepsis and play a crucial role in its pathophysiology. Such alterations are the result of overwhelming inflammation, which negatively affects all the components of the microcirculation. As the severity of microvascular alterations is associated with organ dysfunction and mortality, several strategies have been tested for improving microcirculation. Nevertheless, they are mainly based on the conventional manipulation of systemic hemodynamics to increase the total flow to the organs and tissues. Other therapeutic interventions are still being investigated. In this review, we discuss the pathophysiology of septic microcirculatory dysfunction and its implications for possible treatments.

Microcirculatory dysfunction in sepsis: pathophysiology, clinical monitoring, and potential therapies

Abnormal microvascular perfusion, including decreased functional capillary density and increased blood flow heterogeneity, is observed in early stages of the systemic inflammatory response to infection and appears to have prognostic significance in human sepsis. It is known that improvements in systemic hemodynamics are weakly correlated with the correction of microcirculatory parameters, despite an appropriate treatment of macrohemodynamic abnormalities. Furthermore, conventional hemodynamic monitoring systems available in clinical practice fail to detect microcirculatory parameter changes and responses to treatments, as they do not evaluate intrinsic events that occur in the microcirculation. Fortunately, some bedside diagnostic methods and therapeutic options are specifically directed to the assessment and treatment of microcirculatory changes. In the present review we discuss fundamental aspects of septic microcirculatory abnormalities, including pathophysiology, clinical monitoring, and potential therapies.

Activation of RhoA, but Not Rac1, Mediates Early Stages of S1P-Induced Endothelial Barrier Enhancement

Compromised endothelial barrier function is a hallmark of inflammation. Rho family GTPases are critical in regulating endothelial barrier function, yet their precise roles, particularly in sphingosine-1-phosphate (S1P)-induced endothelial barrier enhancement, remain elusive. Confluent cultures of human umbilical vein endothelial cells (HUVEC) or human dermal microvascular endothelial cells (HDMEC) were used to model the endothelial barrier. Barrier function was assessed by determining the transendothelial electrical resistance (TER) using an electrical cell-substrate impedance sensor (ECIS). The roles of Rac1 and RhoA were tested in S1P-induced barrier enhancement. The results show that pharmacologic inhibition of Rac1 with Z62954982 failed to block S1P-induced barrier enhancement. Likewise, expression of a dominant negative form of Rac1, or knockdown of native Rac1 with siRNA, failed to block S1P-induced elevations in TER. In contrast, blockade of RhoA with the combination of the inhibitors Rhosin and Y16 significantly reduced S1P-induced increases in TER. Assessment of RhoA activation in real time using a fluorescence resonance energy transfer (FRET) biosensor showed that S1P increased RhoA activation primarily at the edges of cells, near junctions. This was complemented by myosin light chain-2 phosphorylation at cell edges, and increased F-actin and vinculin near intercellular junctions, which could all be blocked with pharmacologic inhibition of RhoA. The results suggest that S1P causes activation of RhoA at the cell periphery, stimulating local activation of the actin cytoskeleton and focal adhesions, and resulting in endothelial barrier enhancement. S1P-induced Rac1 activation, however, does not appear to have a significant role in this process.

Pretreatment of human cerebrovascular endothelial cells with CO-releasing molecule-3 interferes with JNK/AP-1 signaling and suppresses LPS-induced proadhesive phenotype

OBJECTIVE

Exogenously administered CO interferes with PMN recruitment to the inflamed organs. The mechanisms of CO-dependent modulation of vascular proadhesive phenotype, a key step in PMN recruitment, are unclear.

METHODS

We assessed the effects/mechanisms of CO liberated from a water-soluble CORM-3 on modulation of the proadhesive phenotype in hCMEC/D3 in an in vitro model of endotoxemia. To this end, hCMEC/D3 were stimulated with LPS (1 μg/mL) for six hours. In some experiments hCMEC/D3 were pretreated with CORM-3 (200 μmol/L) before LPS-stimulation. PMN rolling/adhesion to hCMEC/D3 were assessed under conditions of laminar shear stress (0.7 dyn/cm(2) ). In parallel, expression of adhesion molecules E-selectin, ICAM-1, and VCAM-1 (qPCR), activation of transcription factors, NF-κB and AP-1 (ELISA), and MAPK-signaling (expression/phosphorylation of p38, ERK1/2, and JNK1/2; western blot) were assessed.

RESULTS

The obtained results indicate that CORM-3 pretreatment reduces PMN rolling/adhesion to LPS-stimulated hCMEC/D3 (p < 0.05). Decreased PMN rolling/adhesion to hCMEC/D3 was associated with CORM-3-dependent inhibition of MAPK JNK1/2 activation (Tyr-phosphorylation), inhibition of transcription factor, AP-1 (c-Jun phosphorylation), and subsequent suppression of VCAM-1 expression (p < 0.05).

CONCLUSIONS

These findings indicate that CORM-3 pretreatment interferes with JNK/AP-1 signaling and suppresses LPS-induced upregulation of the proadhesive phenotype in hCMEC/D3.

Total antioxidant and total oxidant states, and serum paraoxonase-1 in neonatal sepsis

BACKGROUND

Paraoxonase-1 (PON-1) is an enzyme with a glycoprotein structure that depends on calcium and which is located in serum high-density lipoprotein (HDL). The aim of this study was to evaluate PON-1, and oxidant/antioxidant state, before and after treatment for neonatal sepsis, and to determine the usability of PON-1 in neonatal sepsis treatment.

METHODS

A total of 35 neonatal sepsis patients and 35 healthy controls were included in the study. Activity of PON-1, total oxidant state (TOS) and total antioxidant state (TAS) were measured and oxidative stress index (OSI) was calculated.

RESULTS

In the neonatal sepsis patients, pre-treatment TAS, TOS and OSI were significantly higher than the post-treatment levels (P < 0.0001, P < 0.0001 and P < 0.0001, respectively), and PON-1 was significantly lower (P < 0.0001). Similarly, pre-treatment TAS, TOS and OSI in the sepsis group were also significantly higher than in the control group (P < 0.0001, P < 0.0001 and P < 0.0001, respectively) and PON-1 was significantly lower (P < 0.0001). Post-treatment TAS in the sepsis group was significantly higher than in the control group (P = 0.009), whereas post-treatment TOS, OSI and PON-1 in the sepsis group were not significantly different to the control group (P = 0.078, P = 0.597 and P = 0.086, respectively).

CONCLUSION

Low serum PON-1 was found in neonatal sepsis. Serum PON-1 is thought to be a useful biomarker to evaluate the effectiveness of treatment and recovery in neonatal sepsis.

Rhodiola rosea suppresses thymus T-lymphocyte apoptosis by downregulating tumor necrosis factor-α-induced protein 8-like-2 in septic rats

In recent years, several studies have shown that Rhodiola rosea can enhance cellular immunity and humoral immune function in mice, and thus, it has become a research hotspot. However, its underlying mechanism of action has remained elusive. The present study investigated whether Rhodiola rosea was able to downregulate the expression of tumor necrosis factor-α-inducible protein 8-like 2 (TIPE2), thereby inhibiting the expression of apoptotic genes, attenuating T-lymphocyte apoptosis and improving immunity in septic mice. A mouse model of caecal ligation and puncture (CLP)-induced sepsis was established, and animals in the treatment group were pre-treated with an intraperitoneal injection of Rhodiola rosea extract, while animals in the control group and sham-operated group were injected with an equivalent amount of normal saline. TIPE2, B-cell lymphoma 2 (Bcl-2), Fas and Fas ligand (FasL) mRNA and protein levels in thymic T cells were determined using reverse transcription quantitative polymerase chain reaction and western blot analysis, respectively. Furthermore, the thymus T-lymphocyte apoptosis rate, thymus T-lymphocyte count and thymus T-lymphocyte sub-sets were assessed using flow cytometry. Levels of T-helper cell type 1 (Th1) cytokines [Interleukin (IL)-2, IL-12 and interferon (IFN)-γ] and Th2 cytokines (IL-4 and IL-10) were determined using ELISA. The results showed that, compared to that in the CLP group, the expression of TIPE2, Fas and FasL in the treatment group was significantly decreased, while the expression of Bcl-2 was increased (P<0.05). The thymus lymphocyte count in the CLP group was significantly higher compared with that in the treatment group (P<0.05). Furthermore, the apoptotic rate of thymus T-lymphocytes in the treatment group was significantly lower than that in the CLP group (P<0.05). In addition, treatment with Rhodiola rosea rescued decreased in the counts of the CD3⁺ T and CD4⁺ T sub-sets of thymus T lymphocytes in the CLP group (P<0.05), while not affecting the increased levels of Th2 cytokines (IL-4 and IL-10) in the CLP group compared with those in the control groups. In addition, the Th1 cytokines (IL-12, IL-2 and IFN-γ) were significantly increased (P<0.05) in the CLP group, and treatment with Rhodiola rosea led to further increases. The thymus index of septic mice treated with Rhodiola rosea as well as their survival rate were improved as compared with those in the CLP group. These findings suggested that Rhodiola rosea has protective effects against sepsis by decreasing apoptosis, increasing Th1 cytokines and enhancing the host’s immunity via the regulation of TIPE2 expression.

Bactericidal activity of curcumin I is associated with damaging of bacterial membrane

Curcumin, an important constituent of turmeric, is known for various biological activities, primarily due to its antioxidant mechanism. The present study focused on the antibacterial activity of curcumin I, a significant component of commercial curcumin, against four genera of bacteria, including those that are Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Pseudomonas aeruginosa). These represent prominent human pathogens, particularly in hospital settings. Our study shows the strong antibacterial potential of curcumin I against all the tested bacteria from Gram-positive as well as Gram-negative groups. The integrity of the bacterial membrane was checked using two differential permeabilization indicating fluorescent probes, namely, propidium iodide and calcein. Both the membrane permeabilization assays confirmed membrane leakage in Gram-negative and Gram-positive bacteria on exposure to curcumin I. In addition, scanning electron microscopy and fluorescence microscopy were employed to confirm the membrane damages in bacterial cells on exposure to curcumin I. The present study confirms the broad-spectrum antibacterial nature of curcumin I, and its membrane damaging property. Findings from this study could provide impetus for further research on curcumin I regarding its antibiotic potential against rapidly emerging bacterial pathogens.

Epalrestat increases glutathione, thioredoxin, and heme oxygenase-1 by stimulating Nrf2 pathway in endothelial cells

Epalrestat (EPS) is the only aldose reductase inhibitor that is currently available for the treatment of diabetic neuropathy. Recently, we found that EPS at near-plasma concentration increases the intracellular levels of glutathione (GSH) in rat Schwann cells. GSH plays a crucial role in protecting endothelial cells from oxidative stress, thereby preventing vascular diseases. Here we show that EPS increases GSH levels in not only Schwann cells but also endothelial cells. Treatment of bovine aortic endothelial cells (BAECs), an in vitro model of the vascular endothelium, with EPS caused a dramatic increase in intracellular GSH levels. This was concomitant with the up-regulation of glutamate cysteine ligase, an enzyme catalyzing the first and rate-limiting step in de novo GSH synthesis. Moreover, EPS stimulated the expression of thioredoxin and heme oxygenase-1, which have important redox regulatory functions in endothelial cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key transcription factor that regulates the expression of antioxidant genes. EPS increased nuclear Nrf2 levels in BAECs. Nrf2 knockdown by siRNA suppressed the EPS-induced glutamate cysteine ligase, thioredoxin-1, and heme oxygenase-1 expression. Interestingly, LY294002, an inhibitor of phosphatidylinositol 3-kinase, abolished the EPS-stimulated GSH synthesis, suggesting that the kinase is associated with Nrf2 activation induced by EPS. Furthermore, EPS reduced the cytotoxicity induced by H2O2 and tert-butylhydroperoxide, indicating that EPS plays a role in protecting cells from oxidative stress. Taken together, the results provide evidence that EPS exerts new beneficial effects on endothelial cells by increasing GSH, thioredoxin, and heme oxygenase-1 levels through the activation of Nrf2. We suggest that EPS has the potential to prevent several vascular diseases caused by oxidative stress.

New directions for sepsis and septic shock research

BACKGROUND

Septic shock is a frequent complication in intensive care unit that can result in multiple organ failure and death. In addition, recent data suggested that severe sepsis and septic shock represent an economic burden. Therefore, septic shock is an important public health problem.

METHOD

In this review, we will focus on the recent evidences concerning the stages of septic shock, the complex macrocirculation and microcirculation relationship, and the importance of those evidences for future resuscitation goals and therapeutic strategies during late septic shock.

RESULT

Recently, two stages of septic shock are suggested. In early stage, hypovolemia is the main contributing factor. During this stage, macrocirculatory and microcirculatory changes run parallel, and fluid resuscitation seems to be effective in restoring the hemodynamic parameters. Late stage of septic shock is characterized by complex microcirculation and macrocirculation relationship.

CONCLUSIONS

Although early goal-directed therapy is a stepwise approach in the treatment of septic shock, tissue perfusion remains an important factor that contributes to septic shock outcome. Because appropriate monitoring of tissue perfusion is a matter of debt, the ideal therapeutic strategy remains a controversial issue that needs further investigations.

Fluid resuscitation therapy in endotoxemic hamsters improves survival and attenuates capillary perfusion deficits and inflammatory responses by a mechanism related to nitric oxide

Background

Relative hypovolemia is frequently found in early stages of severe sepsis and septic shock and prompt and aggressive fluid therapy has become standard of care improving tissue perfusion and patient outcome. This paper investigates the role of the nitric oxide pathway on beneficial microcirculatory effects of fluid resuscitation.

Methods

After skinfold chamber implantation procedures and endotoxemia induction by intravenous Escherichia coli lipopolysaccharide administration (2 mg.kg⁻¹), male golden Syrian hamsters were fluid resuscitated and then sequentially treated with L-N^ω-Nitroarginine and L-Arginine hydrochloride (LPS/FR/LNNA group). Intravital microscopy of skinfold chamber preparations allowed quantitative analysis of microvascular variables including venular leukocyte rolling and adhesion. Macro-hemodynamic, biochemical and hematological parameters as well as survival rate were also evaluated. Endotoxemic hamsters treated with fluid therapy alone (LPS/FR group) and non-treated animals (LPS group) served as controls.

Results

Fluid resuscitation was effective in reducing lipopolysaccharide-induced microcirculatory changes. After 3 hours of lipopolysaccharide administration, non-fluid resuscitated animals (LPS group) had the lowest functional capillary density (1% from baseline for LPS group vs. 19% for LPS/FR one; p <0.05). At the same time point, arteriolar mean internal diameter was significantly wider in LPS/FR group than in LPS one (100% vs. 50% from baseline). Fluid resuscitation also reduced leukocyte-endothelium interactions and sequestration (p <0.05 for LPS vs. LPS/FR group) and increased survival (median survival time: 2 and 5.5 days for LPS and LPS/FR groups, respectively; p <0.05). Nitric oxide synthase inhibition prevented these protective effects, while L-Arginine administration markedly restored many of them.

Conclusion

Our results suggest that the underlying mechanism of fluid therapy is the restoration of nitric oxide bioavailability, because inhibition of NOS prevented many of its beneficial effects. Nevertheless, further investigations are required in experimental models closer to conditions of human sepsis to confirm these results.

Cerebral protection: inflammation, endothelial dysfunction, and postoperative cognitive dysfunction

PURPOSE OF REVIEW

Postoperative cognitive dysfunction (POCD) is a well recognized perioperative syndrome, with approximately 15% of patients over the age of 60 years displaying objectively measured decrease in cognitive function as a consequence of anesthesia and surgery. The exact cause, however, remains unknown. This review aims to update anesthesiologists on the recent advancements in the understanding of the pathophysiology of POCD.

RECENT FINDINGS

Recent evidence suggests that the observed predilection to POCD is likely mediated by a neuro-inflammatory response - with surgery being a major contributing factor. The blood-brain barrier, a highly specialized endothelial layer, is exquisitely sensitive to an inflammatory insult and implicated in the cause of other neurocognitive syndromes also characterized by neuro-inflammation such as cerebral malaria. Inflammatory changes may disrupt the blood-brain barrier and facilitate migration of macrophages into the brain, damaging synapses and neurones and ultimately lead to POCD. This review explores the important question of causality - the potential relationship between inflammation, endothelial dysfunction, and postoperative cognitive decline.

SUMMARY

Recent research points to a central role of a neuro-inflammatory cascade in POCD, with endothelial dysfunction potentially aggravating the insult. Investigating the genomic and molecular mechanisms that underlie the intervariation in the inflammatory response to surgery, improving the identification of appropriate endothelial and inflammatory biomarkers, and developing endothelial modulatory and anti-inflammatory (prevention and resolution) strategies are key areas of future translational research. This is important as the elderly, who show increased susceptibility to this and other perioperative illness syndromes, represent an ever-increasing proportion of patients presenting for surgery.

Prognostic value of serum paraoxonase and arylesterase activity in patients with sepsis

Objective

To determine whether serum paraoxonase (PON) and arylesterase (ARE) activity might predict sepsis mortality.

Methods

Patients with sepsis and healthy control subjects were enrolled in this retrospective study. Serum PON and ARE activity levels were measured. Patients were stratified according to 30-day mortality rates.

Results

Serum PON and ARE activity levels were significantly lower in patients with sepsis ( n = 61) than in healthy controls ( n = 32), and were significantly lower in nonsurviving patients ( n = 22) than in surviving patients ( n = 39). Low PON and ARE activity levels were significantly correlated with poor overall survival in patients with sepsis.

Conclusions

Decreased serum PON and ARE activity is related to poor prognosis in patients with sepsis. Measuring the activity of PON and ARE may represent a new method for evaluating the prognosis of sepsis. In addition, both PON and ARE are potential molecular treatment targets for sepsis.

Reactive oxygen and nitrogen species in sepsis-induced hepatic microvascular dysfunction

Objective and design

Hepatic microvascular dysfunction is a critical event in the development of liver failure during sepsis. Activated blood cells and reactive oxygen and nitrogen species (RONS) have been implicated in the pathogenesis of sepsis.

Methods

Intravital-videomicroscopy was used to determine whether RONS contribute to the recruitment of leukocytes/platelets in the hepatic microvasculature during sepsis. Six hours following cecal-ligation and puncture (CLP), disturbances of the hepatic microvasculature were assessed in WT-mice (C57Bl/6 J; n = 8), in mice lacking gp91^phox(n = 5), overexpressing superoxide-dismutase (SOD, n = 8), in WT-mice treated with a NOS-inhibitor (l-NAME, n = 5), lacking nNOS, eNOS or iNOS (n = 5 each), treated with the NO-donor DetaNO (n = 5), in WT-mice treated with gadolinium-chloride (GdCl₂, n = 5) and compared to a group of WT-mice following a sham operation (n = 8). Six hours post-CLP, the adhesion of leukocytes and platelets in terminal hepatic venules (THV) and sinusoids was quantified.

Results

In WT-mice, CLP elicited increases in the number of adherent leukocytes and platelets. Similar responses to CLP were noted in mice overexpressing SOD or lacking either eNOS or gp91^phox. The blood-cell recruitment was significantly blunted in septic iNOS-knockout mice and this response was reversed by pre-treatment with DetaNO.

Conclusion

These findings suggest that iNOS-derived NO is a determinant of the pro-inflammatory phenotype assumed by the hepatic microvasculature during sepsis.

Sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a diffuse brain dysfunction that occurs secondary to infection in the body without overt CNS infection. SAE is frequently encountered in critically ill patients in intensive care units, and in up to 70% of patients with severe systemic infection. The severity of SAE can range from mild delirium to deep coma. Seizures and myoclonus are infrequent and cranial nerves are almost always spared, but most severe cases have an associated critical illness neuromyopathy. Development of SAE probably involves a number of mechanisms that are not mutually exclusive and vary from patient to patient. Substantial neurological and psychological morbidities often occur in survivors. Mortality is almost always due to multiorgan failure rather than neurological complications, and is almost 70% in patients with severe SAE. Further research into the pathophysiology, management and prevention of SAE is needed. This Review discusses the epidemiology and clinical presentation of SAE. Recent evidence for SAE pathophysiology is outlined and a diagnostic approach to patients with this syndrome is presented. Lastly, prognosis and management of SAE is discussed.