Rho-Proteins and Downstream Pathways as Potential Targets in Sepsis and Septic Shock: What Have We Learned from Basic Research.

Sepsis and septic shock are associated with acute and sustained impairment in the function of the cardiovascular system, kidneys, lungs, liver, and brain, among others. Despite the significant advances in prevention and treatment, sepsis and septic shock sepsis remain global health problems with elevated mortality rates. Rho proteins can interact with a considerable number of targets, directly affecting cellular contractility, actin filament assembly and growing, cell motility and migration, cytoskeleton rearrangement, and actin polymerization, physiological functions that are intensively impaired during inflammatory conditions, such as the one that occurs in sepsis. In the last few decades, Rho proteins and their downstream pathways have been investigated in sepsis-associated experimental models. The most frequently used experimental design included the exposure to bacterial lipopolysaccharide (LPS), in both in vitro and in vivo approaches, but experiments using the cecal ligation and puncture (CLP) model of sepsis have also been performed. The findings described in this review indicate that Rho proteins, mainly RhoA and Rac1, are associated with the development of crucial sepsis-associated dysfunction in different systems and cells, including the endothelium, vessels, and heart. Notably, the data found in the literature suggest that either the inhibition or activation of Rho proteins and associated pathways might be desirable in sepsis and septic shock, accordingly with the cellular system evaluated. This review included the main findings, relevance, and limitations of the current knowledge connecting Rho proteins and sepsis-associated experimental models.

HO-1/PINK1 Regulated Mitochondrial Fusion/Fission to Inhibit Pyroptosis and Attenuate Septic Acute Kidney Injury.

BACKGROUND: Endotoxin-associated acute kidney injury (AKI), a disease characterized by marked oxidative stress and inflammation disease, is a major cause of mortality in critically ill patients. Mitochondrial fission and pyroptosis often occur in AKI. However, the underlying biological pathways involved in endotoxin AKI remain poorly understood, especially those related to mitochondrial dynamics equilibrium disregulation and pyroptosis. Previous studies suggest that heme oxygenase- (HO-) 1 confers cytoprotection against AKI during endotoxic shock, and PTEN-induced putative kinase 1 (PINK1) takes part in mitochondrial dysfunction. Thus, in this study, we examine the roles of HO-1/PINK1 in maintaining the dynamic process of mitochondrial fusion/fission to inhibit pyroptosis and mitigate acute kidney injury in rats exposed to endotoxin. METHODS: An endotoxin-associated AKI model induced by lipopolysaccharide (LPS) was used in our study. Wild-type (WT) rats and PINK1 knockout (PINK1KO) rats, respectively, were divided into four groups: the control, LPS, Znpp+LPS, and Hemin+LPS groups. Rats were sacrificed 6 h after intraperitoneal injecting LPS to assess renal function, oxidative stress, and inflammation by plasma. Mitochondrial dynamics, morphology, and pyroptosis were evaluated by histological examinations. RESULTS: In the rats with LPS-induced endotoxemia, the expression of HO-1 and PINK1 were upregulated at both mRNA and protein levels. These rats also exhibited inflammatory response, oxidative stress, mitochondrial fission, pyroptosis, and decreased renal function. After upregulating HO-1 in normal rats, pyroptosis was inhibited; mitochondrial fission and inflammatory response to oxidative stress were decreased; and the renal function was improved. The effects were reversed by adding Znpp (a type of HO-1 inhibitor). Finally, after PINK1 knockout, there is no statistical difference in the LPS-treated group and Hemin or Znpp pretreated group. CONCLUSIONS: HO-1 inhibits inflammation response and oxidative stress and regulates mitochondria fusion/fission to inhibit pyroptosis, which can alleviate endotoxin-induced AKI by PINK1.

Dysregulated activities of proline-specific enzymes in septic shock patients (sepsis-2).

The proline-specific enzymes dipeptidyl peptidase 4 (DPP4), prolylcarboxypeptidase (PRCP), fibroblast activation protein α (FAP) and prolyl oligopeptidase (PREP) are known for their involvement in the immune system and blood pressure regulation. Only very limited information is currently available on their enzymatic activity and possible involvement in patients with sepsis and septic-shock. The activity of the enzymes was measured in EDTA-plasma of patients admitted to the intensive care unit (ICU): 40 septic shock patients (sepsis-2) and 22 ICU control patients after major intracranial surgery. These data were used to generate receiver operating characteristic (ROC) curves. A survival analysis (at 90 days) and an association study with other parameters was performed. PRCP (day 1) and PREP (all days) enzymatic activities were higher in septic shock patients compared to controls. In contrast, FAP and DPP4 were lower in these patients on all studied time points. Since large differences were found, ROC curves were generated and these yielded area under the curve (AUC) values for PREP, FAP and DPP4 of 0.88 (CI: 0.80-0.96), 0.94 (CI: 0.89-0.99) and 0.86 (CI: 0.77-0.95), respectively. PRCP had a lower predicting value with an AUC of 0.71 (CI: 0.58-0.83). A nominally significant association was observed between survival and the DPP4 enzymatic activity at day 1 (p<0.05), with a higher DPP4 activity being associated with an increase in survival. All four enzymes were dysregulated in septic shock patients. DPP4, FAP and PREP are good in discriminating between septic shock patients and ICU controls and should be further explored to see whether they are already dysregulated in earlier stages, opening perspectives for their further investigation as biomarkers in sepsis. DPP4 also shows potential as a prognostic biomarker. Additionally, the associations found warrant further research.

[Value of serum cholinesterase in the prognosis of septic shock].

OBJECTIVE: To investigate the relationship between serum cholinesterase (SChE) level and the prognosis of patients with septic shock (SS). METHODS: A total of 594 patients with SS admitted to the First Affiliated Hospital of Zhengzhou University from June 2013 to June 2017 were enrolled. General data such as gender, age, acute physiology and chronic health evaluation II (APACHE II) score were recorded as well as routine blood test, procalcitonin (PCT), hepatic function, renal function, coagulation function and blood gas analysis parameters within 48 hours of SS diagnosis. The patients were followed by telephone from September to October in 2019, and the outcome was recorded. The primary outcome was all-cause death 28 days after discharge. The secondary outcomes were all-cause death in intensive care unit (ICU) and 2 years after discharge, and the length of ICU stay. The patients were divided into two groups according to prognosis of 28 days: the survival group and the death group. The clinical data of the two groups were compared. Multivariate Cox regression analysis was used to screen prognostic risk factors of 28 days in patients with SS. The receiver operating characteristic (ROC) curve was used to explore predictive value of liver function parameter SChE for 28-day prognosis of patients with SS. The patients were divided into two groups according to the levels of SChE: the low SChE group (SChE ≤ 4 000 U/L) and the normal SChE group (SChE > 4 000 U/L). Kaplan-Meier survival curves were used to compare the cumulative survival rates without endpoint event of patients with different SChE levels. RESULTS: A total of 385 patients with SS were enrolled according to the inclusion and exclusion criteria, and a total of 356 patients were followed up successfully, with a follow-up rate of 92.5% (356/385). There were 142 survival patients and 214 death patients at 28 days, with a 28-day mortality rate of 60.1% (214/356). There were 116 survival patients and 240 death patients at 2 years, with a 2-year mortality rate of 67.4% (240/356). Compared with the 28-day survival group, the patients in the death group were older and had higher APACHE II score, partial hepatic and renal function parameters, higher level of blood lactate (Lac) and lower levels of white blood cell count (WBC), platelet count (PLT) and SChE with statistically significant differences. Multivariate Cox regression analysis showed that the age [relative risk (RR) = 1.444, 95% confidence interval (95%CI) was 1.090-1.914, P = 0.010], APACHE II score (RR = 2.249, 95%CI was 1.688-2.997, P = 0.000), SChE (RR = 1.469, 95%CI was 1.057-2.043, P = 0.022), and Lac (RR = 2.190, 95%CI was 1.636-2.931, P = 0.000) were independent risk factors for 28-day mortality of patients with SS. The ROC curve analysis showed that SChE had a weak prognostic value for 28-day prognosis of patients with SS [the area under ROC curve (AUC) was 0.574]. However, the combined predictive value of SChE, APACHE II score and Lac was greater than APACHE II score or Lac alone for prediction (AUC: 0.807 vs. 0.785, 0.697), with a sensitivity of 79.9% and a specificity of 68.5%. Compared with the normal SChE group (n = 88), the 28-day mortality of patients in the low SChE group (n = 268) was significantly increased [63.1% (169/268) vs. 51.1% (45/88), P < 0.05], but ICU mortality [59.7% (160/268) vs. 48.9% (43/88)], 2-year mortality [69.8% (187/268) vs. 60.2% (53/88)] or the length of ICU stay [days: 4 (2, 7) vs. 5 (2, 9)] between the two groups showed no statistical significance (all P > 0.05). Kaplan-Meier survival curve analysis showed that the cumulative survival rate without endpoint event of patients in the low SChE group was significantly lower than that in the normal SChE group (Log-Rank test: χ2 = 5.852, P = 0.016). CONCLUSIONS: Increased risk of 28-day mortality in patients with SS whose SChE is below normal. The level of SChE is an independent risk factor for 28-day death in SS patients, and it is one of the indicators to evaluate the short-term prognosis of patients with SS.

Ellipticine Conveys Protective Effects to Lipopolysaccharide-Activated Macrophages by Targeting the JNK/AP-1 Signaling Pathway.

Ellipticine, a natural product from Ochrosia elliptica, has been broadly investigated for its anticancer effects. Although inflammation has been clearly identified as a key factor in the onset and progression of cancer, the relationship between ellipticine and inflammation remains unknown. Hence, the aims of the present study were to assess the effects of ellipticine on the inflammatory responses to lipopolysaccharide (LPS)-induced macrophages and to potentially identify the underlying mechanisms involved. Viability testing showed that ellipticine was not significantly toxic to Raw264.7 cells and actually conveyed protective effects to LPS-stimulated Raw264.7 cells and human peripheral blood monocytes by decreasing the secretion of inflammatory factors (TNF-α and IL-6). The results of western blot analysis and electrophoretic mobility shift assays showed that ellipticine markedly suppressed LPS-induced activation of the JNK/AP-1 (c-Fos and c-Jun) signaling pathway, but not ERK/p38/NF-κB pathway (p65 and p50) activation. Furthermore, ellipticine reduced the inflammatory response and mortality in a mouse model of LPS-induced endotoxic shock. Collectively, these data indicate that ellipticine may be a potential therapeutic agent for the treatment of inflammation-associated diseases.

Evidence for a protective role for the rs805305 single nucleotide polymorphism of dimethylarginine dimethylaminohydrolase 2 (DDAH2) in septic shock through the regulation of DDAH activity.

BACKGROUND: Dimethylarginine dimethylaminohydrolase 2 (DDAH2) regulates the synthesis of nitric oxide (NO) through the metabolism of the endogenous inhibitor of nitric oxide synthase, asymmetric dimethylarginine (ADMA). Pilot studies have associated the rs805305 SNP of DDAH2 with ADMA concentrations in sepsis. This study explored the impact of the rs805305 polymorphism on DDAH activity and outcome in septic shock. METHODS: We undertook a secondary analysis of data and samples collected during the Vasopressin versus noradrenaline as initial therapy in septic shock (VANISH) trial. Plasma and DNA samples isolated from 286 patients recruited into the VANISH trial were analysed. Concentrations of L-Arginine and the methylarginines ADMA and symmetric dimethylarginine (SDMA) were determined from plasma samples. Whole blood and buffy-coat samples were genotyped for polymorphisms of DDAH2. Clinical data collected during the study were used to explore the relationship between circulating methylarginines, genotype and outcome. RESULTS: Peak ADMA concentration over the study period was associated with a hazard ratio for death at 28 days of 3.3 (95% CI 2.0-5.4), p < 0.001. Reduced DDAH activity measured by an elevated ADMA:SDMA ratio was associated with a reduced risk of death in septic shock (p = 0.03). The rs805305 polymorphism of DDAH2 was associated with reduced DDAH activity (p = 0.004) and 28-day mortality (p = 0.02). Mean SOFA score and shock duration were also reduced in the less common G:G genotype compared to heterozygotes and C:C genotype patients (p = 0.04 and p = 0.02, respectively). CONCLUSIONS: Plasma ADMA is a biomarker of outcome in septic shock, and reduced DDAH activity is associated with a protective effect. The polymorphism rs805305 SNP is associated with reduced mortality, which is potentially mediated by reduced DDAH2 activity. TRIAL REGISTRATION: ISRCTN Registry, ISRCTN20769191 . Registered on 20 September 2012.

Caspase-8 Collaborates with Caspase-11 to Drive Tissue Damage and Execution of Endotoxic Shock.

The execution of shock following high dose E. coli lipopolysaccharide (LPS) or bacterial sepsis in mice required pro-apoptotic caspase-8 in addition to pro-pyroptotic caspase-11 and gasdermin D. Hematopoietic cells produced MyD88- and TRIF-dependent inflammatory cytokines sufficient to initiate shock without any contribution from caspase-8 or caspase-11. Both proteases had to be present to support tumor necrosis factor- and interferon-ß-dependent tissue injury first observed in the small intestine and later in spleen and thymus. Caspase-11 enhanced the activation of caspase-8 and extrinsic cell death machinery within the lower small intestine. Neither caspase-8 nor caspase-11 was individually sufficient for shock. Both caspases collaborated to amplify inflammatory signals associated with tissue damage. Therefore, combined pyroptotic and apoptotic signaling mediated endotoxemia independently of RIPK1 kinase activity and RIPK3 function. These observations bring to light the relevance of tissue compartmentalization to disease processes in vivo where cytokines act in parallel to execute diverse cell death pathways.

Role of matrix metalloproteinases 2 and 9, toll-like receptor 4 and platelet-leukocyte aggregate formation in sepsis-associated thrombocytopenia.

BACKGROUND: The development of thrombocytopenia in sepsis is a poor prognostic indicator associated with a significantly increased mortality risk. Mechanisms underlying this phenomenon remain to be clearly elucidated. Matrix metalloproteinases (MMPs) are enzymes that regulate the turnover of the extra-cellular matrix. MMP-2 is recognised as a platelet agonist with MMP-9 proposed as an inhibitor of platelet activation. The existence of MMP-9 in platelets is a subject of debate. There is limited evidence thus far to suggest that toll-like receptor 4 (TLR-4) and platelet-leukocyte aggregate (PLA) formation may be implicated in the development of sepsis-associated thrombocytopenia. OBJECTIVES: To investigate whether MMP -2/-9, toll-like receptor 4 (TLR-4) or platelet-leukocyte aggregate (PLA) formation are implicated in a decline in platelet numbers during septic shock. METHODS: This was an observational study which recruited healthy controls, non-thrombocytopenic septic donors and thrombocytopenic septic donors. MMP-2, MMP-9 and TLR-4 platelet surface expression as well as PLA formation was examined using flow cytometry. In addition MMP-2 and MMP-9 were examined by gelatin zymography and enzyme-linked immunosorbent assay (ELISA) using a 3 compartment model (plasma, intraplatelet and platelet membrane). RESULTS: There was no difference found in MMP-2, MMP-9 or TLR-4 levels between non-thrombocytopenic and thrombocytopenic septic donors. PLA formation was increased in thrombocytopenic patients. MMP-9 was detected in platelets using flow cytometry, gelatin zymography and ELISA techniques. CONCLUSIONS: Platelet consumption into PLAs may account for the development of thrombocytopenia in septic shock. MMP-9 is found in platelets and it is upregulated during septic shock.

Prognostic value of neglected biomarker in sepsis patients with the old and new criteria: predictive role of lactate dehydrogenase.

OBJECTIVES: This study examined the pH, lactate dehydrogenase (LDH), and heart rate values on the first day of hospitalization in patients with a prediagnosis of sepsis and biomarkers that may predict mortality. METHODS: Patients hospitalized in an emergency intensive care unit with a diagnosis of systemic inflammatory response syndrome were classified as having sepsis (n = 28), septic shock (n = 8), or severe sepsis (n = 8) according to International Sepsis Guidelines (old criteria). Forty-four patients were classified as having sepsis (n = 4), septic shock (n = 30), or infection (n = 10) according to The Third International Consensus Definitions for Sepsis and Septic Shock (new criteria). The effects of these patients' laboratory values on survival between groups were compared. Significant values were evaluated by χ2 automatic interaction detection analysis. RESULTS: When the patients were categorized according to the new classification criteria, there was an increase in the number of septic shock patients and a decrease in the number of sepsis patients. In addition, 10 patients were removed from the sepsis category. There was a significant difference between ex and discharged patients in terms of heart rate, pH, sodium bicarbonate, lactate, and LDH (P= .007, P= .002, P= .034, P= .009, and P= .002, respectively). Based on a χ2 automatic interaction detection analysis of the significant values, pH, LDH, and heart rate were prominent predictors of prognosis. CONCLUSIONS: Systemic pH, LDH, and heart rate values may be used to determine the best time to discharge patients from intensive care to other, more affordable hospital units.

Caspase-8 inhibition represses initial human monocyte activation in septic shock model.

In septic patients, the onset of septic shock occurs due to the over-activation of monocytes. We tested the therapeutic potential of directly targeting innate immune cell activation to limit the cytokine storm and downstream phases. We initially investigated whether caspase-8 could be an appropriate target given it has recently been shown to be involved in microglial activation. We found that LPS caused a mild increase in caspase-8 activity and that the caspase-8 inhibitor IETD-fmk partially decreased monocyte activation. Furthermore, caspase-8 inhibition induced necroptotic cell death of activated monocytes. Despite inducing necroptosis, caspase-8 inhibition reduced LPS-induced expression and release of IL-1ß and IL-10. Thus, blocking monocyte activation has positive effects on both the pro and anti-inflammatory phases of septic shock. We also found that in primary mouse monocytes, caspase-8 inhibition did not reduce LPS-induced activation or induce necroptosis. On the other hand, broad caspase inhibitors, which have already been shown to improve survival in mouse models of sepsis, achieved both. Thus, given that monocyte activation can be regulated in humans via the inhibition of a single caspase, we propose that the therapeutic use of caspase-8 inhibitors could represent a more selective alternative that blocks both phases of septic shock at the source.

Berberine Decreased Inducible Nitric Oxide Synthase mRNA Stability through Negative Regulation of Human Antigen R in Lipopolysaccharide-Induced Macrophages.

Berberine, a major isoquinoline alkaloid found in medicinal herbs, has been reported to possess anti-inflammatory effects; however, the underlying mechanisms responsible for its actions are poorly understood. In the present study, we investigated the inhibitory effects of berberine and the molecular mechanisms involved in lipopolysaccharide (LPS)-treated RAW 264.7 and THP-1 macrophages and its effects in LPS-induced septic shock in mice. In both macrophage cell types, berberine inhibited the LPS-induced nitric oxide (NO) production and inducible NO synthase (iNOS) protein expression, but it had no effect on iNOS mRNA transcription. Suppression of LPS-induced iNOS protein expression by berberine occurred via a human antigen R (HuR)-mediated reduction of iNOS mRNA stability. Molecular data revealed that the suppression on the LPS-induced HuR binding to iNOS mRNA by berberine was accompanied by a reduction in nucleocytoplasmic HuR shuttling. Pretreatment with berberine reduced LPS-induced iNOS protein expression and the cytoplasmic translocation of HuR in liver tissues and increased the survival rate of mice with LPS-induced endotoxemia. These results show that the suppression of iNOS protein expression by berberine under LPS-induced inflammatory conditions is associated with a reduction in iNOS mRNA stability resulting from inhibition of the cytoplasmic translocation of HuR.

Plasma glutathione reductase activity and prognosis of septic shock.

BACKGROUND: Our aim was to investigate whether plasma glutathione reductase (GR) activity is well correlated with the erythrocyte-reduced glutathione (GSH)/glutathione disulfide (GSSG) ratio and is associated with the mortality of septic shock. MATERIALS AND METHODS: This study was conducted on male Sprague-Dawley rats and patients admitted to the intensive care unit with septic shock. To induce endotoxemia in rats, vehicle or lipopolysaccharide (LPS) at dosages of 5 or 10 mg/kg were injected into a tail vein. Animals were then euthanized 6 h post-LPS. Based on the 28-d mortality, the enrolled patients were divided into the survivors and nonsurvivors. We obtained blood samples from patients at admission (0 h) and 24 h after admission to the intensive care unit. RESULTS: In endotoxemic rats, the erythrocyte GSH/GSSG ratio, erythrocyte GR activity, and plasma GR activity in the 10 mg/kg of LPS group were lower than those in the sham and 5 mg/kg of LPS groups. In patients with septic shock, decrease in plasma GR activity at 24 h was independently associated with an increase in 28-d mortality (odds ratio, 0.828; 95% confidence interval, 0.690-0.992, P = 0.041). Plasma GR activity was correlated with erythrocyte GR activity (Spearman ρ = 0.549, P < 0.001) and the erythrocyte GSH/GSSG ratio (rho = 0.367, P = 0.009) at 24 h. CONCLUSIONS: Plasma GR activity was well correlated with erythrocyte GR activity and the erythrocyte GSH/GSSG ratio, and a decrease in plasma GR activity was associated with an increase in the mortality of septic shock patients.

Selective Inhibition of SIRT2 Improves Outcomes in a Lethal Septic Model.

BACKGROUND: Seven isoforms of histone deacetylase Class III have been reported - Sirtuin (SIRT) 1-7. We recently demonstrated that EX-527, an inhibitor of SIRT1, reduces mortality in a mouse model of lethal-cecal-ligationand- puncture (CLP)-induced septic shock. Our present study was aimed at determining whether selective inhibition of SIRT2, with AGK2, would decrease animal death and attenuate the inflammatory response in a septic model. METHODS: Experiment I: C57BL/6J mice were intraperitoneally given either AGK2 (82 mg/kg) in dimethyl sulfoxide (DMSO) or DMSO alone, and 2 h later subjected to CLP. Survival was monitored for 240 hours. Experiment II: mice treated the same way as Experiment I, were grouped into (i) DMSO vehicle, and (ii) AGK2, with sham mice (operating but without any treatment) serving as controls. Peritoneal fluid and peripheral blood were examined at 24 and 48 hours for cytokine production. Samples of blood at 48 h were also allocated to assess coagulability using Thrombelastography (TEG). Morphological changes of bone marrow were evaluated from long bones (femurs and tibias) with hematoxylin and eosin (H&E) staining. Bone marrow atrophy was quantified by a blinded pathologist. Experiment III: cytokines in supernatant of the cultured normal primary splenocytes were measured after the cells were stimulated by lipopolysaccharide and treated with or without AGK2 (10 µM) for 6 hours. RESULTS: AGK2 significantly reduced mortality and decreased levels of cytokines in blood (TNF-α: 298.3±24.6 vs 26.8±2.8 pg/ml, p=0.0034; IL-6: 633.4±82.8 vs 232.6±133.0 pg/ml, p=0.0344) and peritoneal fluid (IL-6: 704.8±67.7 vs 391.4±98.5 pg/ml, p=0.033) compared to vehicle control. Also, AGK2 suppressed the TNF-α and IL-6 production in the cultured splenocytes (TNF-α: 68.1±6.4 vs 23.9±2.8 pg/ml, p=0.0009; IL-6: 73.1±4.2 vs 49.6±3.0 pg/ml; p=0.0051). The TEG data showed that the mice subjected to CLP displayed prolonged fibrin formation and fibrin cross-linkage time, slower clot formation, decreased platelet function, and clot rigidity. AGK2 treatment was associated with dramatic improvements in fibrin cross-linkage and clot formation times, without a significant impact on the clot initiation parameters or platelet function. Additionally, AGK2 significantly attenuated the bone marrow atrophy (58.3±6.5 vs 30.0±8.2%, p=0.0262). CONCLUSION: Selective inhibition of SIRT2 significantly improves survival, and attenuates sepsis-associated "cytokine storm", coagulopathy, and bone marrow atrophy in a mouse model of lethal septic shock.

Fusion Peptides CPU1 and CPU2 Inhibit Matrix Metalloproteinases and Protect Mice from Endotoxin Shock Within a Strict Time Window.

Endotoxin shock induction in mice is a commonly used animal model to evaluate the protective effect of biologically active reagents. After an lipopolysaccharides (LPS) stimulus, matrix metalloproteinase-8 (MMP-8) and matrix metalloproteinase-9 (MMP-9) are rapidly degranulated and released by neutrophils, aside other enzymes and effector molecules. MMPs cleave extracellular matrix components and cytokines, and such processes contribute to shock syndrome development. CPU1 and CPU2 are two peptide MMP inhibitors with different in vitro IC50 values to several key enzymes, including MMP-8 and MMP-9. In vivo work confirmed that CPU1 and CPU2 protected mice from endotoxin shock after intravenous and intraperitoneal injections. Furthermore, their minimal effective dose after an intravenous injection and the maximum time interval between intraperitoneal peptide injection (150 mg/kg) and intravenous LPS injection were determined. With the use of an indirect competitive ELISA, plasma CPU1 and CPU2 concentrations in different experimental settings were measured. In addition, the acuteness of MMP-9 release in the mouse circulation after an intravenous LPS injection was confirmed with the zymography technique. Our findings reinforce previous work with other inhibitors about a strict time window within which effective MMP inhibition is needed to obtain significant survival rate improvements and also show that, with strict pharmacokinetic monitoring, potent protease inhibitors may in the future become life-savers in shock conditions.

Arginine infusion in patients with septic shock increases nitric oxide production without haemodynamic instability.

Arginine deficiency in sepsis may impair nitric oxide (NO) production for local perfusion and add to the catabolic state. In contrast, excessive NO production has been related to global haemodynamic instability. Therefore, the aim of the present study was to investigate the dose-response effect of intravenous arginine supplementation in post-absorptive patients with septic shock on arginine-NO and protein metabolism and on global and regional haemodynamics. Eight critically ill patients with a diagnosis of septic shock participated in this short-term (8 h) dose-response study. L-Arginine-HCl was continuously infused [intravenously (IV)] in three stepwise-increasing doses (33, 66 and 99 µmol·kg-1·h-1). Whole-body arginine-NO and protein metabolism were measured using stable isotope techniques, and baseline values were compared with healthy controls. Global and regional haemodynamic parameters were continuously recorded during the study. Upon infusion, plasma arginine increased from 48±7 to 189±23 µmol·l-1 (means±S.D.; P<0.0001). This coincided with increased de novo arginine (P<0.0001) and increased NO production (P<0.05). Sepsis patients demonstrated elevated protein breakdown at baseline (P<0.001 compared with healthy controls), whereas protein breakdown and synthesis both decreased during arginine infusion (P<0.0001). Mean arterial and pulmonary pressure and gastric mucosal-arterial partial pressure of carbon dioxide difference (Pr-aCO2) gap did not alter during arginine infusion (P>0.05), whereas stroke volume (SV) increased (P<0.05) and arterial lactate decreased (P<0.05). In conclusion, a 4-fold increase in plasma arginine with intravenous arginine infusion in sepsis stimulates de novo arginine and NO production and reduces whole-body protein breakdown. These potential beneficial metabolic effects occurred without negative alterations in haemodynamic parameters, although improvement in regional perfusion could not be demonstrated in the eight patients with septic shock who were studied.

3,4,5-Trihydroxycinnamic acid increases heme-oxygenase-1 (HO-1) and decreases macrophage infiltration in LPS-induced septic kidney.

We previously demonstrated that 3,4,5-trihydorxycinnamic acid (THC), a derivative of hydroxycinnamic acids, possesses protective effect in lipopolysaccharide (LPS)-induced endotoxemia models. However, the effects of THC in LPS-induced septic kidney are still unclear. Therefore, the present study was carried out to examine the effects of THC in LPS-challenged septic kidney using mesangial cell line and Balb/c mice. THC pretreatment effectively inhibited LPS-induced macrophage infiltration and the secretion of pro-inflammatory cytokines in the kidney of LPS-challenged animals. Pretreatment of rat mesangial cells with THC significantly attenuated LPS-induced PGE2 production and COX-2 expression. THC also significantly suppressed LPS-induced expression of MCP-1 in LPS-activated septic kidney and rat mesangial cells. In addition, THC significantly attenuated LPS-induced degradation of IκB-α in LPS-induced rat mesangial cells. THC also increased the expression of heme oxygenase-1 (HO-1) in LPS-challenged septic kidney and mesangial cells. Multiple signaling pathways including p38 and AKT have been observed to be involved in the THC-induced activation of HO-1 expression. The present data clearly demonstrate that THC protects LPS-challenged septic kidney by decreasing macrophage infiltration and increasing HO-1 expression, suggesting that THC might be a valuable therapeutic agent for compromised kidney in sepsis.

Association of poly(ADP-ribose) polymerase activity in circulating mononuclear cells with myocardial dysfunction in patients with septic shock.

BACKGROUND: Severe sepsis and septic shock are the leading causes of morbidity and mortality in hospitalized patients. This study aimed to investigate the association of poly (ADP-ribose) polymerase-1 (PARP-1) activity in circulating mononuclear cells with myocardial dysfunction in patients with septic shock. METHODS: A total of 64 patients with septic shock were divided into the survival group (n = 41) and the nonsurvival group (n = 23) according to mortality at 28 days after enrollments. PARP-1 activity in circulating mononuclear cells, brain natriuretic peptide, Acute Physiology and Chronic Health Evaluation II score, the cardiac index (CI), the cardiac function index (CFI), global ejection fraction (GEF), and the left ventricular contractility index (dp/dt max) were measured after admission to the intensive care unit. RESULTS: PARP-1 activity in circulating mononuclear cells of nonsurvival patients with septic shock was significantly higher than that in survival patients. PARP-1 activity in circulating mononuclear cells was strongly, negatively correlated with the CI, the CFI, GEF, and dp/dt max. Multiple Logistic regression analysis showed that PARP-1 activity in circulating mononuclear cells was an independent risk factor of myocardial dysfunction. The optimal cutoff point of PARP-1 activity for predicting 28-day mortality was 942 nmol/L with a sensibility of 78.2% and specificity of 65.1%. CONCLUSION: PARP-1 activity in circulating mononuclear cells is significantly associated with myocardial dysfunction and may have prognostic value in patients with septic shock.

Role of testis-specific high-mobility-group protein in transcriptional regulation of inducible nitric oxide synthase expression in the liver of endotoxic shock mice.

Inducible nitric oxide synthase (iNOS) plays a central role in tissue damage during endotoxic shock. However, the underlying mechanisms that control transcription of iNOS are not completely defined. A screening strategy with DNA pull-down technology and two-dimensional difference in gel electrophorcsis (2D-DIGE) analysis was used to identify regulators that interact with the iNOS promoter. We found 14 proteins that bind to the iNOS promoter in the liver of endotoxic shock mice. After matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) analysis, one of these proteins was identified as testis-specific high-mobility-group protein (tsHMG), an alternative splicing isoform encoded by the mitochondrial transcription factor A gene. We identified the binding sites of tsHMG on the iNOS promoter using a LiquiChip system, and further confirmed interactions between tsHMG and iNOS by RT-PCR, western blotting and immunofluorescence. Functional analysis by over-expression and RNA interference of tsHMG revealed that tsHMG regulates lipopolysaccharide-stimulated iNOS expression. These results indicate that tsHMG participates in modulation of iNOS expression in the early stage of endotoxic shock.