Simvastatin Protects Against T Cell Immune Dysfunction in Abdominal Sepsis

Bioinformatic Analysis and Machine Learning Methods in Neonatal Sepsis: Identification of Biomarkers and Immune Infiltration

The disease neonatal sepsis (NS) poses a serious threat to life, and its pathogenesis remains unclear. Using the Gene Expression Omnibus (GEO) database, differentially expressed genes (DEGs) were identified and functional enrichment analyses were conducted. Three machine learning algorithms containing the least absolute shrinkage and selection operator (LASSO), support vector machine recursive feature elimination (SVM-RFE), and random forest (RF) were applied to identify the optimal feature genes (OFGs). This study conducted CIBERSORT to present the abundance of immune infiltrates between septic and control neonates and assessed the relationship between OFGs and immune cells. In total, 44 DEGs were discovered between the septic and control newborns. Throughout the enrichment analysis, DEGs were primarily related to inflammatory signaling pathways and immune responses. The OFGs derived from machine learning algorithms were intersected to yield four biomarkers, namely Hexokinase 3 (HK3), Cystatin 7 (CST7), Resistin (RETN), and Glycogenin 1 (GYG1). The potential biomarkers were validated in other datasets and LPS-stimulated HEUVCs. Septic infants showed a higher proportion of neutrophils (p < 0.001), M0 macrophages (p < 0.001), and regulatory T cells (p = 0.004). HK3, CST7, RETN, and GYG1 showed significant correlations with immune cells. Overall, the biomarkers offered promising insights into the molecular mechanisms of immune regulation for the prediction and treatment of NS.

Statin Use and Mortality among Patients Hospitalized with Sepsis: A Retrospective Cohort Study within Southern California, 2008–2018

Background

Despite early goal-directed therapy, sepsis mortality remains high. Statins exhibit pleiotropic effects.

Objective

We sought to compare mortality outcomes among statin users versus nonusers who were hospitalized with sepsis.

Methods

Retrospective cohort study of patients (age ≥18 years) during 1/1/2008–9/30/2018. Mortality was compared between statin users and nonusers and within statin users (hydrophilic versus lipophilic, fungal versus synthetic derivation, and individual statins head-to-head). Multivariable Cox regression models were used to estimate hazard ratios (HR) for 30-day and 90-day mortality. Inverse probability treatment weighting (IPTW) analysis was performed to account for indication bias.

Results

Among 128,161 sepsis patients, 34,088 (26.6%) were prescribed statin drugs prior to admission. Statin users compared to nonusers had a 30-day and 90-day mortality HR (95% CI) of 0.80 (0.77–0.83) and 0.79 (0.77–0.81), respectively. Synthetic derived statin users compared to fungal derived users had a 30- and 90-day mortality HR (95% CI) of 0.86 (0.81–0.91) and 0.85 (0.81–0.89), respectively. Hydrophilic statin users compared to lipophilic users had a 30-day and 90-day mortality HR (95% CI) of 0.90 (0.81–1.01) and 0.86 (0.78–0.94), respectively. Compared to simvastatin, 30-day mortality HRs (95% CI) were 0.85 (0.66–1.10), 0.87 (0.82–0.92), 0.87 (0.76–0.98), and 1.22 (1.10–1.36) for rosuvastatin, atorvastatin, pravastatin, and lovastatin, respectively.

Conclusion

Statin use was associated with lower mortality in patients hospitalized with sepsis. Hydrophilic and synthetic statins were associated with better outcomes than lipophilic and fungal-based preparations.

Simvastatin inhibits the inflammation and oxidative stress of human neutrophils in sepsis via autophagy induction

Simvastatin exerts a protective effect during sepsis (SP) in animal models; however, the underlying mechanism is not completely understood, particularly in human SP. Neutrophils are a critical effector in the host inflammatory response to SP. Therefore, the present study aimed to investigate the effect of simvastatin on neutrophils in human SP. Neutrophils were isolated from the peripheral venous blood of adult patients with SP and healthy volunteers (HP). Cell viability was analyzed using the MTT assay. Intracellular reactive oxygen species (ROS) generation and the concentrations of inflammatory mediators were also assessed using flow cytometry and ELISA. The results demonstrated that the cell viability of neutrophils from the SP group was significantly decreased compared with that in the HP group, and that treatment with simvastatin partly reversed the reduced cell viability. Furthermore, simvastatin administration significantly decreased ROS production and the concentrations of TNF‑α and IL‑6, which were significantly increased in neutrophils isolated from the SP group. Simvastatin also enhanced autophagy induction, as indicated by the promotion of the conversion of LC3I to LC3II and the increased expression levels of Beclin 1 in SP neutrophils. Treatment with 3‑methyladenine, an autophagy inhibitor, completely blocked the protective effects of simvastatin on neutrophils from SP, including the effects of simvastatin on the inhibition of inflammation, oxidative stress and improving cell viability. Collectively, the present study provided evidence for the simvastatin‑induced autophagic process of neutrophils involved in human SP, which protects neutrophils and partially attenuates the inflammatory response and oxidative stress. Therefore, the augmentation of neutrophil autophagy may serve as a potential therapeutic target for patients with SP.

Histone Deacetylation Inhibitors as Modulators of Regulatory T Cells

Regulatory T cells (T_regs) are important mediators of immunological self-tolerance and homeostasis. Being cluster of differentiation 4⁺Forkhead box protein3⁺ (CD4⁺FOXP3⁺), these cells are a subset of CD4⁺ T lymphocytes and can originate from the thymus (tT_regs) or from the periphery (pT_regs). The malfunction of CD4⁺ T_regs is associated with autoimmune responses such as rheumatoid arthritis (RA), multiple sclerosis (MS), type 1 diabetes (T1D), inflammatory bowel diseases (IBD), psoriasis, systemic lupus erythematosus (SLE), and transplant rejection. Recent evidence supports an opposed role in sepsis. Therefore, maintaining functional T_regs is considered as a therapy regimen to prevent autoimmunity and allograft rejection, whereas blocking T_reg differentiation might be favorable in sepsis patients. It has been shown that T_regs can be generated from conventional naïve T cells, called iT_regs, due to their induced differentiation. Moreover, T_regs can be effectively expanded in vitro based on blood-derived tT_regs. Taking into consideration that the suppressive role of T_regs has been mainly attributed to the expression and function of the transcription factor Foxp3, modulating its expression and binding to the promoter regions of target genes by altering the chromatin histone acetylation state may turn out beneficial. Hence, we discuss the role of histone deacetylation inhibitors as epigenetic modulators of T_regs in this review in detail.

Regulatory T cells: Possible mediators for the anti-inflammatory action of statins

Statins beside their main effect on reducing the progression of cardiovascular disease through pharmacological inhibition of the endogenous cholesterol synthesis, have additional pleiotropic effects including antiinflammatory effects mediated through the induction of suppressor regulatory T cells (Tregs). Statin-induced expansion of Tregs reduces chronic inflammation and may have beneficial effects in autoimmune diseases. However, statins could represent a double-edged sword in immunomodulation. Drugs that act by increasing the concentration of Tregs could enhance the risk of cancers, particularly in the elderly and may have adverse effects in neurodegenerative disorders and infectious diseases. In the present paper, we review the experimental studies that evaluate the effects of statins on Treg cells in autoimmune and inflammatory diseases and we discuss potential therapeutic applications of statins in this setting.

Prophylactic simvastatin treatment modulates the immune response and increases survival of mice following induction of lethal sepsis

Objective

To investigate whether and how simvastatin mediates protection from lethal sepsis, using a mouse model.

Methods

Sixty C57BL/6 mice were selected and divided into three groups (“control,” “model,” and “observation”; n = 20 mice per group). Mice in the model and observation groups underwent cecal ligation and puncture; mice in the observation group received simvastatin. After 24 hours of induced sepsis, serum concentrations of IL-6, TNF-α, IL-1, and IL-10 were measured by ELISA. Serum malondialdehyde (MDA) concentrations and serum superoxide dismutase (SOD) activities were quantified by radioimmunoassay.

Results

The mean duration of survival of mice in the observation group was significantly longer than that of the model group. The serum concentrations of IL-6, TNF-α, IL-1, IL-10, and MDA were significantly higher in the observation group than in the control group. Serum SOD activities were significantly lower in the observation group than in the control group.

Conclusions

Simvastatin can alleviate symptoms of sepsis in mice and improve their rates of survival. The mechanism of action of simvastatin may be mediated by inhibition of the systemic inflammatory response and oxidative stress.

Simvastatin Inhibits Endotoxin-Induced Apoptosis in Liver and Spleen Through Up-Regulation of Survivin/NF-κB/p65 Expression

Endotoxemia is associated by dysregulated apoptosis of immune and non-immune cells. We investigated whether simvastatin has anti-apoptotic effects, and induces hepatocytes and lymphocytes survival signaling in endotoxin-induced liver and spleen injuries. Wistar rats were divided into the groups pretreated with simvastatin (20 or 40 mg/kg, orally) prior to a non-lethal dose of lipopolysaccharide (LPS), the LPS group, and the control. The severity of tissue inflammatory injuries was expressed as hepatic damage scores (HDS) and spleen damage scores (SDS), respectively. The apoptotic cell was detected by TUNEL (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling) and immunohistochemical staining (expression of cleaved caspase-3, and anti-apoptotic Bcl-xL, survivin and NF-κB/p65). Simvastatin dose-dependently abolished HDS and SDS induced by LPS (p < 0.01), respectively. Simvastatin 40 mg/kg significantly decreased apoptotic index and caspase-3 cleavage in hepatocytes and lymphocytes (p < 0.01 vs. LPS group, respectively), while Bcl-XL markedly increased accordingly with simvastatin doses. In the simvastatin, groups were determined markedly increased cytoplasmic expression of survivin associated with nuclear positivity of NF-κB, in both hepatocytes and lymphocytes (p < 0.01 vs. LPS group). Cell-protective effects of simvastatin against LPS seemed to be mediated by up-regulation of survivin, which leads to reduced caspase-3 activation and inhibition of hepatocytes and lymphocytes apoptosis.

Effects of simvastatin on the function of splenic CD4+ and CD8+ T cells in sepsis mice

Simvastatin may be beneficial for treating sepsis due to its immune-regulating properties, although the mechanisms remain elusive. Herein, we hypothesized simvastatin may attenuate T cell dysfunction induced by sepsis. To test this hypothesis, we used a model based on cecal ligation and puncture (CLP) to induce sepsis in mice. Male C57BL/6 mice were pre-treated with simvastatin (0.2 μg/g of body weight) before CLP. The expression of B and T lymphocyte attenuator (BTLA) on splenic CD4⁺ T cells and T cell apoptosis, CD4⁺ and CD8⁺ T cells were quantified by flow cytometry. Immunohistochemical staining was performed to evaluate the loss of immune effector cells. Formation of TNF-α and interleukin 10 (IL-10) in the spleen and plasma levels of presepsin, IL-1β, and IL-6 were determined using enzyme-linked immunosorbent assay. Simvastatin markedly inhibited the reduction in cytokine secretion from lipopolysaccharide (LPS)-stimulated splenocytes. Simvastatin-treated mice had significantly decreased the percentages of negative costimulatory receptor BTLA on CD4 T cell expression. Simvastatin markedly reduced T cell apoptosis through downregulating the Fas/FasL expression and decrease the percentage of caspase-3 activity in spleen tissue. There was significantly less depletion of splenic CD4⁺ and CD8⁺ T cells in simvastatin-treated mice. Simvastatin reduced plasma levels of presepsin, IL-1β, and IL-6. Simvastatin can be a powerful regulator of immune function under sepsis conditions by improving T cell function in sepsis.

Influence of autophagy on acute kidney injury in a murine cecal ligation and puncture sepsis model

The role of autophagy in the maintenance of renal homeostasis during sepsis is not well understood. We therefore aimed to determine the influence of autophagy on kidney during sepsis using a murine sepsis model, i.e. cecal ligation and puncture (CLP). In CLP treated animals, the number of autolysosomes observed by electron microscopy increased over time. The number of autophagosomes in CLP animals decreased relative sham operated controls at 24 hrs after CLP, indicating that autophagy flux is already diminishing by that time. Moreover, CLP induced an increase in LC3-II/LC3-I ratio at 6-8 hrs, demonstrated in western blots, as well as an increase in GFP-LC3 dots at 6-8 hrs and 24 hrs, using immunofluorescence and anti-LC3 and LAMP1 antibodies on tissue sections from GFP-LC3 transgenic mice. LC3-II/LC3-I ratio and the number of co-localized GFP-LC3 dots and LAMP1 signals (GFP LC3 + LAMP1 dots) in CLP mice at 24 hrs were significantly reduced compared with data obtained at 6-8 hrs. Notably, acceleration of autophagy by rapamycin resulted in improvement of renal function that was associated with improvement in the histologic severity of tubular epithelial injury in CLP treated animals. Autophagy in the kidney was significantly slowed in the kidney during the acute phase of sepsis; nonetheless, autophagy in kidney appears to play a protective role against sepsis.

Metabolic Inflammatory Complex in Sepsis: Septic Cachexia as a Novel Potential Therapeutic Target

Despite several decades of focused investigation, sepsis remains a major cause of mortality in critically ill patients. Advancements in intensive care have enabled more patients to survive the acute phase of sepsis than previously, but a growing number of them progress to chronic critical illness. The failure of previous randomized clinical trials of anti-inflammatory agents to show any pro-survival benefit in septic patients underscores current thought that simple anti-inflammatory strategies are ineffective because the inhibitory effect of anti-inflammatory agents undermines the immune response to pathogens. New strategies with the dual capability of ameliorating inflammation in organs while stimulating antimicrobial activity are eagerly awaited. On the other hand, the metabolic alterations associated with systemic inflammatory response, including mitochondrial dysfunction and metabolic shift, are closely linked through a nexus of signaling pathways and signaling molecules. Preventing these metabolic derangements may be an alternative way to control excessive inflammation, an intriguing possibility that has not been fully explored. New insight into the molecular pathogenesis of sepsis and sepsis-associated chronic critical illness has led to the recognition of septic cachexia, a life-threatening form of metabolic inflammatory complex associated with multiple organ dysfunction. The potential for septic cachexia to serve as a novel target disease state to improve the clinical outcome of septic patients is discussed in this review.

A Population-Based Cohort Study on the Drug-Specific Effect of Statins on Sepsis Outcome

BACKGROUND

Whether statin treatment, proved by recent experimental studies to have an antimicrobial activity, exerts a drug- or a class-specific effect in sepsis remains unknown.

METHODS

Short-term mortality in patients with sepsis was analyzed using data from the National Health Insurance Research Database. Use of statins was defined as the cumulative use of a specific statin (atorvastatin, simvastatin, or rosuvastatin) for > 30 days prior to the index sepsis admission. We determined the association between statin and sepsis outcome by multivariate-adjusted Cox models and propensity score (PS)-matched analysis, using a 1:1:1 PS matching technique.

RESULTS

A total of 52,737 patients with sepsis fulfilled the inclusion criteria, of which 1,855 were prescribed atorvastatin, 916 were prescribed simvastatin, and 732 were prescribed rosuvastatin. Compared with nonusers, simvastatin (hazard ratio [HR], 0.72; 95% CI, 0.58-0.90) and atorvastatin (HR, 0.78; 95% CI, 0.68-0.90) were associated with an improved 30-day survival, whereas rosuvastatin was not (HR, 0.87; 95% CI, 0.73-1.04). Using rosuvastatin as the reference, atorvastatin (HR, 0.79; 95% CI, 0.64-0.99) and simvastatin (HR, 0.77; 95% CI, 0.59-0.99) had superior effectiveness in preventing mortality.

CONCLUSIONS

Compatible with in vitro experimental findings, our results suggest that the drug-specific effect of statins on sepsis is not correlated to their lipid-lowering potency.

Effect of Atorvastatin on the Disease Activity and Severity of Rheumatoid Arthritis: Double-Blind Randomized Controlled Trial

INTRODUCTION

HMG-CoA (3-hydroxy-3- methylglutary lcoenzyme A) reductase inhibitors (statins) have anti-inflammatory properties which may be particularly useful in rheumatoid arthritis to suppress disease activity and inflammatory factors.

AIM

The purpose of this clinical trial was to determine anti-inflammatory properties of statins in rheumatoid arthritis.

MATERIALS AND METHODS

Eighty Iranian patients with rheumatoid arthritis, aged between 19 to 75 years were recruited to take part in this randomized, double-blind placebo-controlled trial. Subjects were randomly allocated to two groups to take atorvastatin or placebo 40 mg daily as an adjunct to current disease-modifying anti-rheumatic drugs (DMARDs) treatment. Disease Activity Score-28 (DAS28), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), swollen joint count (SJC) & tender joint count (TJC) were assessed before and after three months intervention.

RESULTS

Analysis was based on intention to treat. DAS28 significantly declined in the atorvastatin group in comparison with placebo (p< 0.001). SJC, TJC, CRP and ESR also were significantly dropped in the atorvastatin group in comparison with placebo.

CONCLUSION

It can be concluded that atorvastatin can suppress RA activity and inflmmatory factors in RA patients for high to moderate grade of inflmmation.

Farnesyltransferase inhibitor, tipifarnib, prevents galactosamine/lipopolysaccharide-induced acute liver failure

Acute liver failure (ALF) is a fatal syndrome associated with massive hepatocyte death. There is no cure for ALF except liver transplantation. Protein farnesylation is a lipid modification of cysteine residues that is catalyzed by farnesyltransferase (FTase) and has been proposed as an integral component of acute inflammation. Previously, we have demonstrated that FTase inhibitors improve survival in mouse models of endotoxemia and sepsis. Here we studied the effects of FTase inhibitor, tipifarnib, on galactosamine (GalN)/lipopolysaccharide (LPS)-induced ALF. The effects of tipifarnib (10 mg/kg, i.p.) were studied in GalN (400 mg/kg, i.p.)- and LPS (3 μg/kg)-challenged mice by histological and biochemical analyses. Galactosamine/LPS administration caused prominent liver injury characterized by the increased plasma alanine aminotransferase and aspartic aminotransferase levels, leading to significant mortality in mice. Tipifarnib inhibited GalN/LPS-induced caspase 3 activation, inflammatory cytokine production, and c-Jun N-terminal kinase phosphorylation in the liver. On the other hand, tipifarnib upregulated antiapoptotic protein, Bcl-xL, in the liver after GalN/LPS challenge. Tipifarnib also protected primary hepatocytes from GalN/tumor necrosis factor α-induced cell death by inhibiting caspase 3 activation and upregulating antiapoptotic proteins. Galactosamine/LPS-induced liver injury was associated with increased protein farnesylation in the liver. Tipifarnib prevented protein farnesylation in the liver and markedly attenuated liver injury and mortality in GalN/LPS-challenged mice. These results suggest that protein farnesylation is a novel potential molecular target to prevent hepatocyte death and acute inflammatory liver failure in fulminant hepatitis.

Rac1-dependent secretion of platelet-derived CCL5 regulates neutrophil recruitment via activation of alveolar macrophages in septic lung injury

Accumulating evidence suggest that platelets play an important role in regulating neutrophil recruitment in septic lung injury. Herein, we hypothesized that platelet-derived CCL5 might facilitate sepsis-induced neutrophil accumulation in the lung. Abdominal sepsis was induced by CLP in C57BL/6 mice. CLP increased plasma levels of CCL5. Platelet depletion and treatment with the Rac1 inhibitor NSC23766 markedly reduced CCL5 in the plasma of septic mice. Moreover, Rac1 inhibition completely inhibited proteasePAR4-induced secretion of CCL5 in isolated platelets. Immunoneutralization of CCL5 decreased CLP-induced neutrophil infiltration, edema formation, and tissue injury in the lung. However, inhibition of CCL5 function had no effect on CLP-induced expression of Mac-1 on neutrophils. The blocking of CCL5 decreased plasma and lung levels of CXCL1 and CXCL2 in septic animals. CCL5 had no effect on neutrophil chemotaxis in vitro, suggesting an indirect effect of CCL5 on neutrophil recruitment. Intratracheal challenge with CCL5 increased accumulation of neutrophils and formation of CXCL2 in the lung. Administration of the CXCR2 antagonist SB225002 abolished CCL5-induced pulmonary recruitment of neutrophils. Isolated alveolar macrophages expressed significant levels of the CCL5 receptors CCR1 and CCR5. In addition, CCL5 triggered significant secretion of CXCL2 from isolated alveolar macrophages. Notably, intratracheal administration of clodronate not only depleted mice of alveolar macrophages but also abolished CCL5-induced formation of CXCL2 in the lung. Taken together, our findings suggest that Rac1 regulates platelet secretion of CCL5 and that CCL5 is a potent inducer of neutrophil recruitment in septic lung injury via formation of CXCL2 in alveolar macrophages.

Increased statin prescribing does not lower pneumonia risk

BACKGROUND

Investigators have attributed protective effects of statins against pneumonia and other infections. However, these reports are based on observational data where treatments are not assigned randomly. We aimed to determine if the protective effects of statins against pneumonia are due to nonrandom treatment assignment.

METHODS

We built a cohort consisting of 124 695 Medicare beneficiaries diagnosed with an acute myocardial infarction (AMI) for which we had complete claims data. We considered patients who survived at least 30 days post-AMI (full sample), or who survived for 1 year post-AMI (survivors). First, we used ordinary least squares (OLS) and logit models to determine if receiving a statin was protective against pneumonia. Second, to control for nonrandom treatment assignment, we performed an instrumental variables analysis using geographic treatment rates as an instrument. All models included patient demographics, medications, diagnoses, length of hospital stay, and out-of-pocket drug costs as covariates. Our outcome measure was a pneumonia diagnosis during the 1 year following AMI.

RESULTS

A total of 76 994 patients (61.9%) filled a statin prescription, and 19 078 (15.3%) were diagnosed with pneumonia. Using OLS, the statin coefficient was -0.016 (P < .001), indicating that statins are associated with a reduction in pneumonia. Using instrumental variables, we find that statin prescriptions are not associated with a reduction in pneumonia. For the full sample, statin coefficients ranged from -0.001 to -0.01 (P > .6).

CONCLUSIONS

For patients with AMI, the protective effect of statins against pneumonia is most likely the result of nonrandom treatment assignment (ie, a healthy-user bias).

Cholesterol rather than procalcitonin or C-reactive protein predicts mortality in patients with infection

Serum cholesterol procalcitonin (PCT) and C-reactive protein (CRP) levels were measured consecutively in 76 critically ill patients at admission to the intensive care unit. The presence of infection was defined according to the CDC (Centers for Disease Control and Prevention) criteria; in-house mortality, underlying diseases, and severity of sepsis were monitored. Nonsurvivors had significantly lower cholesterol levels compared with survivors (69 mg/dL [range, 37-88 mg/dL] vs. 96 mg/dL [range, 71-132 mg/dL], P = 0.006) whereas no significant differences were noted for serum PCT and CRP levels. In a cohort of patients with cholesterol levels of 50 mg/dL or less, 82% did not survive as compared with patients with cholesterol levels of 100 mg/dL or greater (mortality, 21%). In a control group without infection, no difference of cholesterol, PCT, or CRP was found between survivors and nonsurvivors. Our data show that low cholesterol levels in patients with infectious disease have a prognostic value and may be useful markers to identify high-risk patients already at admission.

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1's multiple functions.

Antioxidant protection of statins in acute kidney injury induced by sepsis

Objective Evaluating the effect of preconditioning with simvastatin in acute kidney injury induced by sepsis. Method Male adult Wistar rats were divided into the following groups: SHAM (control); SHAM+Statin (0.5 mg/kg simvastatin, orally); Sepsis (cecal puncture ligation – CPL); Sepsis+Statin. Physiological parameters, peritoneal fluid culture, renal function, oxidative metabolites, severity of acute kidney injury and animal survival were evaluated. Results The treatment with simvastatin in induced sepsis showed elevation of creatinine clearance with attenuation of generation of oxidative metabolites, lower severity of acute kidney injury and reduced mortality. Conclusion This investigation confirmed the renoprotection with antioxidant principle of the simvastatin in acute kidney injury induced by sepsis in an experimental model.

Proinflammatory role of neutrophil extracellular traps in abdominal sepsis

Excessive neutrophil activation is a major component in septic lung injury. Neutrophil-derived DNA may form extracellular traps in response to bacterial invasions. The aim of the present study was to investigate the potential role of neutrophil extracellular traps (NETs) in septic lung injury. Male C57BL/6 mice were treated with recombinant human (rh)DNAse (5 mg/kg) after cecal ligation and puncture (CLP). Extracellular DNA was stained by Sytox green, and NET formation was quantified by confocal microscopy and cell-free DNA in plasma, peritoneal cavity, and lung. Blood, peritoneal fluid, and lung tissue were harvested for analysis of neutrophil infiltration, NET levels, tissue injury, as well as CXC chemokine and cytokine formation. We observed that CLP caused increased formation of NETs in plasma, peritoneal cavity, and lung. Administration of rhDNAse not only eliminated NET formation in plasma, peritoneal cavity, and bronchoalveolar space but also reduced lung edema and tissue damage 24 h after CLP induction. Moreover, treatment with rhDNAse decreased CLP-induced formation of CXC chemokines, IL-6, and high-mobility group box 1 (HMGB1) in plasma, as well as CXC chemokines and IL-6 in the lung. In vitro, we found that neutrophil-derived NETs had the capacity to stimulate secretion of CXCL2, TNF-α, and HMGB1 from alveolar macrophages. Taken together, our findings show that NETs regulate pulmonary infiltration of neutrophils and tissue injury via formation of proinflammatory compounds in abdominal sepsis. Thus we conclude that NETs exert a proinflammatory role in septic lung injury.

Nuclear factor of activated T cells regulates neutrophil recruitment, systemic inflammation, and T-cell dysfunction in abdominal sepsis

The signaling mechanisms regulating neutrophil recruitment, systemic inflammation, and T-cell dysfunction in polymicrobial sepsis are not clear. This study explored the potential involvement of the calcium/calcineurin-dependent transcription factor, nuclear factor of activated T cells (NFAT), in abdominal sepsis. Cecal ligation and puncture (CLP) triggered NFAT-dependent transcriptional activity in the lung, spleen, liver, and aorta in NFAT-luciferase reporter mice. Treatment with the NFAT inhibitor A-285222 prior to CLP completely prevented sepsis-induced NFAT activation in all these organs. Inhibition of NFAT activity reduced sepsis-induced formation of CXCL1, CXCL2, and CXCL5 chemokines and edema as well as neutrophil infiltration in the lung. Notably, NFAT inhibition efficiently reduced the CLP-evoked increases in HMBG1, interleukin 6 (IL-6), and CXCL5 levels in plasma. Moreover, administration of A-285222 restored sepsis-induced T-cell dysfunction, as evidenced by markedly decreased apoptosis and restored proliferative capacity of CD4 T cells. Along these lines, treatment with A-285222 restored gamma interferon (IFN-γ) and IL-4 levels in the spleen, which were markedly reduced in septic mice. CLP-induced formation of regulatory T cells (CD4(+) CD25(+) Foxp3(+)) in the spleen was also abolished in A-285222-treated animals. All together, these novel findings suggest that NFAT is a powerful regulator of pathological inflammation and T-cell immune dysfunction in abdominal sepsis. Thus, our data suggest that NFAT signaling might be a useful target to protect against respiratory failure and immunosuppression in patients with sepsis.

Statins as modulators of regulatory T-cell biology

Statins are pharmacological inhibitors of the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), an enzyme responsible for the synthesis of cholesterol. Some recent experimental studies have shown that besides their effects on the primary and secondary prevention of cardiovascular diseases, statins may also have beneficial anti-inflammatory effects through diverse mechanisms. On the other hand, the induction and activity of regulatory T cells (Treg) are key processes in the prevention of pathology during chronic inflammatory and autoimmune diseases. Hence, strategies oriented towards the therapeutic expansion of Tregs are gaining special attention among biomedical researchers. The potential effects of statins on the biology of Treg are of particular importance because of their eventual application as in vivo inducers of Treg in the treatment of multiple conditions. In this paper we review the experimental evidence pointing out to a potential effect of statins on the role of regulatory T cells in different conditions and discuss its potential clinical significance.