Olmesartan Ameliorates Organ Injury and Mortality in Rats With Peritonitis-Induced Sepsis.

INTRODUCTION: Sepsis and related complications lead to high morbidity and mortality in humans and animals. Olmesartan medoxomil (OLM), a nonpeptide angiotensin II type 1 receptor blocker, has antiinflammatory and antioxidative effects in various experimental animal models. The present study aimed to investigate whether OLM protects against sepsis in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in anesthetized rats. OLM was administered intraperitoneally 3 h after CLP onset. Hemodynamic, biochemical, and inflammatory parameters were analyzed. RESULTS: The administration of OLM in CLP rats significantly improved their survival rate. Moreover, OLM mitigated CLP-induced hypotension and organ injury (indicated by biochemical parameters), but not tachycardia. OLM significantly reduced the plasma levels of interleukin-6 and nitric oxide. CONCLUSIONS: OLM markedly attenuated CLP-induced hypotension and organ injury, and hence improved survival by inhibiting the inflammatory response and nitrosative stress in this clinically relevant model of sepsis.

Angiotensin-(1-7) attenuates organ injury and mortality in rats with polymicrobial sepsis.

BACKGROUND: Sepsis and related multiple organ dysfunction result in high morbidity and mortality. Angiotensin (Ang)-(1-7), a biologically active peptide, has various opposing effects of Ang II. Because the effect of Ang-(1-7) on sepsis is unknown, in this study we aimed to determine the impact of Ang-(1-7) on pathophysiologic changes in a clinically relevant model of polymicrobial sepsis induced by cecal ligation and puncture (CLP). METHODS: Sepsis was induced by CLP in rats under anesthesia. Rats were randomized to one of the following five groups: (1) sham-operated group, (2) Ang-(1-7) (1 mg/kg intravenously infused for 1 h) at 3 h and 6 h after sham operation, (3) CLP, (4) Ang-(1-7) at 3 h after CLP, and (5) Ang-(1-7) at 3 h and 6 h after CLP. Rats were observed for 24 h after CLP surgery and then killed for subsequent histological examination. RESULTS: Ang-(1-7) significantly improved the survival of septic rats (83.3% vs. 36.4% at 24 h following CLP; p = 0.009). Ang-(1-7) attenuated the CLP-induced decreased arterial pressure and organ dysfunction, indicated by diminished biochemical variables and fewer histological changes. Ang-(1-7) significantly reduced the level of plasma interleukin-6 and pulmonary superoxide production (p < 0.05). Moreover, caspase-3 and cytoplasmic IκB expression in liver was significantly lower in the Ang-(1-7)-treated CLP rats (p < 0.05). CONCLUSIONS: In this clinically relevant model of sepsis, Ang-(1-7) ameliorates CLP-induced organ dysfunction and improves survival, possibly through suppressing the inflammatory response, oxidative stress, and apoptosis, suggesting that Ang-(1-7) could be a potential novel therapeutic approach to treatment of peritonitis and polymicrobial sepsis.

Levosimendan attenuates multiple organ injury and improves survival in peritonitis-induced septic shock: studies in a rat model.

INTRODUCTION: The aim of this study was to investigate the effects of levosimendan on rodent septic shock induced by cecal ligation and puncture (CLP). METHODS: Three hours after peritonitis-induced sepsis, male Wistar rats were randomly assigned to receive an intravenous infusion of levosimendan (1.2 µg/kg/min for 10 min and then 0.3 µg/kg/min for 6 h) or an equivalent volume of saline and vehicle (5% dextrose) solution. RESULTS: The levosimendan-treated CLP animals had significantly higher arterial pressure and lower biochemical indices of liver and kidney dysfunction compared to the CLP animals (P < 0.05). Plasma interleukin-1ß, nitric oxide and organ superoxide levels in the levosimendan-treated CLP group were less than those in CLP rats treated with vehicle (P < 0.05). In addition, the inducible nitric oxide synthase (iNOS) in lung and caspase-3 expressions in spleen were significantly lower in the levosimendan-treated CLP group (P < 0.05). The administration of CLP rats with levosimendan was associated with significantly higher survival (61.9% vs. 40% at 18 h after CLP, P < 0.05). At postmortem examination, the histological changes and neutrophil filtration index in liver and lung were significantly attenuated in the levosimendan-treated CLP group (vs. CLP group, P < 0.05). CONCLUSIONS: In this clinically relevant model of septic shock induced by fecal peritonitis, the administration of levosimendan had beneficial effects on haemodynamic variables, liver and kidney dysfunction, and metabolic acidosis. (1) Lower levels of interleukin-1ß, nitric oxide and superoxide, (2) attenuation of iNOS and caspase-3 expressions, and (3) decreases of neutrophil infiltration by levosimendan in peritonitis-induced sepsis animals suggest that anti-inflammation and anti-apoptosis effects of levosimendan contribute to prolonged survival.

Loss of plasma fibrinogen contributes to platelet hyporeactivity in rats with septic shock.

INTRODUCTION: Dysregulated host response to infection causes life-threatening organ dysfunction. Excessive inflammation and abnormal blood coagulation can lead to disseminated intravascular coagulation (DIC) and multiple-organ failure in the late sepsis stages. Platelet function impairment in sepsis contributes to bleeding, secondary infection, and tissue injury. Platelet transfusion is considered in patients with sepsis with DIC and bleeding; however, its benefits are limited and of low quality. Fibrinogen plays a crucial role in platelet function, and establishing a fibrin network binds to activated integrin αIIbß3 and promotes outside-in signaling that amplifies platelet functions. However, the role of fibrinogen in sepsis-induced platelet dysfunction remains unclear. MATERIALS AND METHODS: We evaluated the effects of fibrinogen on platelet hyporeactivity during septic shock in adult male Wistar rats using lipopolysaccharide (LPS) injection and cecal ligation and puncture (CLP) surgery. Changes in the hemodynamic, biochemical, and coagulation parameters were examined. Platelet activation and aggregation were measured using whole-blood assay, 96-well plate-based aggregometry, and light-transmission aggregometry. Additionally, platelet adhesion, spreading, and fibrin clot retraction were evaluated. RESULTS: Rats with LPS- and CLP-induced sepsis displayed considerable decreases in plasma fibrinogen levels and platelet aggregation, adhesion, spreading, and clot retraction. The aggregation of platelets obtained from rats with sepsis was markedly augmented by fibrinogen supplementation. Additionally, fibrinogen administration improved platelet adhesion, spreading, and clot retraction in rats with sepsis. CONCLUSIONS: Fibrinogen supplementation could serve as a potential therapeutic intervention for alleviating platelet hyporeactivity in patients with sepsis and bleeding.

Possible biomarkers of early mortality in peritonitis-induced sepsis rats.

BACKGROUND: Sepsis induced by cecal ligation and puncture (CLP) is accompanied by circulatory failure, multiple organ dysfunction syndrome, metabolic acidosis, and electrolyte imbalance in rats. However, it remains uncertain which parameters can be used to predict the mortality of septic rats. Thus, the aim of this study was to examine which possible biomarkers were associated with mortality in the CLP-induced sepsis model. MATERIALS AND METHODS: After the carotid artery and vein were cannulated, rats were subsequently subjected to CLP or sham operation. The changes of hemodynamics, biochemical variables, blood gas, and electrolytes were monitored during the 18-h observation. RESULTS: The CLP surgery caused circulatory failure, multiple organ dysfunction syndrome, metabolic acidosis, electrolyte imbalance, and death. Compared with survivors, nonsurvivors showed significant difference in (1) blood glucose; (2) lactate dehydrogenase, alanine aminotransferase, aspartate aminotransferase, creatinine, and blood urea nitrogen in serum; and (3) base excess, HCO3(-), PaCO2, potassium, and calcium in whole blood at 9 h after CLP. No significant difference in blood pressure, heart rate, pressor response to noradrenaline, rectal temperature, total protein, albumin, PaO2, and sodium was observed between nonsurvivors and survivors. However, after multifactor dimensionality reduction analysis, the union of HCO3(-) and blood glucose had the biggest testing balanced accuracy. CONCLUSIONS: These results indicate that HCO3(-) plus blood glucose serves as the best biomarker of early death in rats with CLP-induced sepsis. Thus, these parameters could guide experimental procedures for making the right interventions when utilizing CLP as a sepsis model in rats.

Hyperoncotic albumin attenuates lung and intestine injuries caused by peritonitis-induced sepsis in rats.

BACKGROUND: Hyperoncotic albumin may be a therapeutic option to improve tissue perfusion and organ injury in sepsis. To clarify the hypothesis and its mechanism, hyperoncotic albumin was administered to the rats in a polymicrobial sepsis-peritonitis model. MATERIALS AND METHODS: Peritonitis was induced by a surgery of cecal ligation and puncture (CLP) in 27 male Wistar rats. For control purposes, sham operations without ligating and puncturing the cecum were performed in 20 rats. Three hours later, rats were randomized to receive intravenously 3 mL/kg of 5% albumin, 25% albumin, or normal saline. All the hemodynamic and biochemical parameters were measured during the 18-h observation. RESULTS: In septic rats, 25% albumin attenuated hypotension, vascular hyporeactivity to norepinephrine, and the elevated serum levels of lactate dehydrogenase and blood urea nitrogen. However, these improvements were not noted in CLP rats after 5% albumin treatment. In addition, 25% albumin decreased metabolic acidosis and improved the CLP-induced hypoperfusion in the intestine and kidney. Superoxide levels in the aorta and lung and the protein expression of inducible nitric oxide synthase in the lung were also attenuated by 25% albumin in CLP rats. Microscopic findings confirmed that 25% albumin attenuated the substantial swelling and cell infiltration in the intestine and lung caused by CLP. CONCLUSIONS: In this sepsis rat model, 25% albumin reduced macro- and microhemodynamic changes and attenuated intestine and lung injuries in peritonitis-induced sepsis.

Stimulation of angiotensin II type 2 receptor attenuates organ injury in rats with polymicrobial sepsis.

BACKGROUND: Both inflammation and oxidative stress contribute to the pathogenesis of sepsis and its associated organ damage. Angiotensin-(1-7), acting through the Mas receptor and angiotensin II-type 2 receptors (AT2R), could attenuate organ dysfunction and improve survival in rats with sepsis. However, the role of AT2R in inflammation and oxidative stress in rats with sepsis is unclear. Therefore, this study examined the modulatory effects and molecular mechanism of AT2R stimulation in rats with polymicrobial sepsis. METHODS: Male Wistar rats underwent cecal ligation and puncture (CLP) or sham surgery followed by the administration of saline or CGP42112 (a selective, high-affinity agonist of AT2R, 50 µg/kg intravenously) at 3 hours after sham surgery or CLP. The changes in hemodynamics, biochemical variables, and plasma levels of chemokines and nitric oxide were detected during the 24-hour observation. Organ injury was evaluated by histological examination. RESULTS: We found that CLP evoked delayed hypotension, hypoglycemia, and multiple organ injuries, characterized by elevated plasma biochemical parameters and histopathological changes. These effects were attenuated by treatment with CGP42112. CGP42112 significantly attenuated plasma chemokines and nitric oxide production and reduced liver inducible nitric oxide synthase and nuclear factor kappa-B expression. More importantly, CGP42112 significantly improved the survival of rats with sepsis (50% vs. 20% at 24 h after CLP, p < 0.05). CONCLUSION: The protective effects of CGP42112 may be related to anti-inflammatory responses, suggesting that the stimulation of AT2R is a promising therapeutic candidate for the treatment of sepsis.

Antimicrobial peptide cathelicidin LL-37 preserves intestinal barrier and organ function in rats with heat stroke.

Global warming increases the incidence of heat stroke (HS) and HS causes the reduction of visceral blood flow during hyperthermia, leading to intestinal barrier disruption, microbial translocation, systemic inflammation and multiple organ failure. Cathelicidin LL-37 exhibits antimicrobial activities, helps innate immunity within the gut to maintain intestinal homeostasis, and augments intestinal wound healing and barrier function. Thus, we evaluated the effects and possible mechanisms of cathelicidin LL-37 on HS. Wistar rats were placed in a heating-chamber of 42 ̊C to induce HS. Changes in rectal temperature, hemodynamic parameters, and survival rate were measured during the experimental period. Blood samples and ilea were collected to analyze the effects of LL-37 on systemic inflammation, multiple organ dysfunction, and intestinal injury. Furthermore, LS174T and HT-29 cells were used to assess the underlying mechanisms. Our data showed cathelicidin LL-37 ameliorated the damage of intestinal cells induced by HS. Intestinal injury, systemic inflammation, and nitrosative stress (high nitric oxide level) caused by continuous hyperthermia were attenuated in HS rats treated with cathelicidin LL-37, and hence, improved multiple organ dysfunction, coagulopathy, and survival rate. These beneficial effects of cathelicidin LL-37 were attributed to the protection of intestinal goblet cells (by increasing transepithelial resistance, mucin-2 and Nrf2 expression) and the improvement of intestinal barrier function (less cyclooxygenase-2 expression and FITC-dextran translocation). Interestingly, high cathelicidin expression in the ileal samples of inflammatory bowel disease patients was associated with better clinical outcome. These results suggest that cathelicidin LL-37 could prevent heat stress-induced intestinal damage and heat-related illnesses.

Supercritical carbon dioxide-decellularized arteries exhibit physiologic-like vessel regeneration following xenotransplantation in rats.

Currently, many techniques are used for decellularization of grafts, including physical, enzymatic, and chemical treatments. Indeed, decellularized xenogenic grafts provide superior outcomes than alternative synthetic conduits. However, vascular grafts produced by these methods are not perfect; their defects include defective vessel wall structures, detergent residues, and the development of aneurysms after grafting. Therefore, it is essential to develop a more appropriate process to produce decellularized vascular grafts. Supercritical carbon dioxide (ScCO2) has been used in decellularization technologies in recent years. It is beneficial for the long-term preservation of tissues and regeneration of new vessels. We have previously reported that ScCO2-produced acellular porcine corneas show excellent biocompatibility following lamellar corneal transplantation in rabbits. In this study, we wanted to use this method to fabricate vascular grafts (ScCO2-decellularized rabbit femoral artery (DFA)) and analyze their efficacy, parameters regarding rejection by the recipient's (ACI/NKyo rats) immune system and biocompatibility, structural regeneration, and functionality in vivo. The results indicated that the ScCO2-DFA showed higher biocompatibility, enhanced chemotactic migration of endothelial progenitor cells, lower risk of vasculopathy, lower inflammatory and splenic immune responses, and better physiological-like tension responses after xenotransplantation (XTP) in ACI/NKyo rats compared with the results obtained after XTP using detergent decellularized vascular grafts (SDS-DFA). In conclusion, ScCO2 is an excellent decellularization technique in the fabrication of biocompatible vascular grafts and has tremendous application in vascular regenerative medicine.

Improvement in heat stress-induced multiple organ dysfunction and intestinal damage through protection of intestinal goblet cells from prostaglandin E1 analogue misoprostol.

AIMS: Heat stroke is a life-threatening disorder triggered by thermoregulatory failure. Hyperthermia-induced splanchnic hypoperfusion has been reported to induce intestinal barrier dysfunction and systemic immune response that ultimately cause multiple-organ failure and death. Intestinal goblet cells contribute greatly to the formation of mucus barrier, which hinders translocation of gut microorganisms. Studies have reported that misoprostol can not only alleviate ischemic injury but also protect GI mucosal layer. Therefore, we evaluated the effects of misoprostol on intestinal goblet cells after heat stress and on multiple-organ dysfunction in heat stroke rats. MAIN METHODS: Heat stress was established in the heating chamber and followed by misoprostol treatment. Changes in hemodynamics, organ function indices, inflammation, oxidative stress, and survival rate were analyzed. Furthermore, ilea and LS174T cells were used to examine intestinal functions. KEY FINDINGS: Heat stress caused dysfunction of intestinal goblet cells and damage to ilea by increasing oxidative stress and apoptosis. Increased nitrosative stress and inflammation accompanied by hypotension, hypoperfusion, tachycardia, multiple-organ dysfunction, and death were observed in the heat stroke rat model. Treatment of LS174T cells with misoprostol not only decreased oxidative stress and apoptosis but also reduced cytotoxicity caused by heat stress. Moreover, misoprostol prevented disruption of the enteric barrier, multiple-organ injury, and death in rats with heat stroke. SIGNIFICANCE: This study indicates that misoprostol could alleviate intestinal damage and organ injury caused by heat stress and be a potential therapy for heat-related illnesses.

Decoy receptor 3 inhibits renal mononuclear leukocyte infiltration and apoptosis and prevents progression of IgA nephropathy in mice.

The progression of IgA nephropathy (IgAN), the most frequent type of primary glomerulonephritis, is associated with high levels of mononuclear leukocyte infiltration into the kidney. These cells consist mainly of T cells and macrophages. Our previous study showed that a decoy receptor 3 (DCR3) gene therapy can prevent the development of a mouse autoimmune glomerulonephritis model by its potent immune modulating effects (Ka SM, Sytwu HK, Chang DM, Hsieh SL, Tsai PY, Chen A. J Am Soc Nephrol 18: 2473-2485, 2007). Here, we tested the hypothesis that DCR3 might prevent the progression of IgAN, an immune complex-mediated primary glomerulonephritis, by inhibiting T cell activation, renal T cell/macrophage infiltration, and protecting the kidney from apoptosis. We used a progressive IgAN (Prg-IgAN) model in B cell-deficient mice, because the mice are characterized by a dramatic proliferation of activated T cells systemically and progressive NF-κB activation in the kidney. We treated the animals with short-term gene therapy with DCR3 plasmids by hydrodynamics-based gene delivery. When the mice were euthanized on day 21, we found that, compared with empty vector-treated (disease control) Prg-IgAN mice, DCR3 gene therapy resulted in 1) systemic inhibition of T cell activation and proliferation; 2) lower serum levels of proinflammatory cytokines; 3) improved proteinuria, renal function, and renal pathology (inhibiting the development of marked glomerular proliferation, crescent formation, glomerulosclerosis, and interstitial inflammation); 5) suppression of T cell and macrophage infiltration into the periglomerular interstitium of the kidney; and 5) a reduction in apoptotic figures in the kidney. On the basis of these findings, DCR3 might be useful therapeutically in preventing the progression of IgAN.

SPAK-knockout mice manifest Gitelman syndrome and impaired vasoconstriction.

Polymorphisms in the gene encoding sterile 20/SPS1-related proline/alanine-rich kinase (SPAK) associate with hypertension susceptibility in humans. SPAK interacts with WNK kinases to regulate the Na(+)-K(+)-2Cl(-) and Na(+)-Cl(-) co-transporters [collectively, N(K)CC]. Mutations in WNK1/4 and N(K)CC can cause changes in BP and dyskalemia in humans, but the physiologic role of SPAK in vivo is unknown. We generated and analyzed SPAK-null mice by targeting disruption of exons 9 and 10 of SPAK. Compared with SPAK(+/+) littermates, SPAK(+/-) mice exhibited hypotension without significant electrolyte abnormalities, and SPAK(-/-) mice not only exhibited hypotension but also recapitulated Gitelman syndrome with hypokalemia, hypomagnesemia, and hypocalciuria. In the kidney tissues of SPAK(-/-) mice, the expression of total and phosphorylated (p-)NCC was markedly decreased, but that of p-OSR1, total NKCC2, and p-NKCC2 was significantly increased. We observed a blunted response to thiazide but normal response to furosemide in SPAK(-/-) mice. In aortic tissues, total NKCC1 expression was increased but p-NKCC1 was decreased in SPAK-deficient mice. Both SPAK(+/-) and SPAK(-/-) mice had impaired responses to the selective α(1)-adrenergic agonist phenylephrine and the NKCC1 inhibitor bumetanide, suggesting that impaired aortic contractility may contribute to the hypotension of SPAK-null mice. In summary, SPAK-null mice have defects of NCC in the kidneys and NKCC1 in the blood vessels, leading to hypotension through renal salt wasting and vasodilation. SPAK may be a promising target for antihypertensive therapy.

Angiotensin-(1-7) treatment blocks lipopolysaccharide-induced organ damage, platelet dysfunction, and IL-6 and nitric oxide production in rats.

Sepsis can lead to shock, multiple organ failure, and even death. Platelets play an active role in the pathogenesis of sepsis-induced multiple organ failure. Angiotensin (Ang)-(1-7), a biologically active peptide, counteracts various effects of Ang II and attenuates inflammatory responses, reactive oxygen species production, and apoptosis. We evaluated the effects of Ang-(1-7) on organ injury and platelet dysfunction in rats with endotoxaemia. We treated male Wistar rats with saline or lipopolysaccharide (LPS, 10 mg, intravenously) then Ang-(1-7) (1 mg/kg, intravenous infusion for 3 h beginning 30 min after LPS administration). We analysed several haemodynamic, biochemical, and inflammatory parameters, as well as platelet counts and aggregation. Ang-(1-7) improved hypotension and organ dysfunction, and attenuated plasma interleukin-6, chemokines and nitric oxide production in rats after LPS administration. The LPS-induced reduction in platelet aggregation, but not the decreased platelet count, was restored after Ang-(1-7) treatment. The protein expression of iNOS and IκB, but not phosphorylated ERK1/2 and p38, was diminished in Ang-(1-7)-treated LPS rats. The histological changes in liver and lung were significantly attenuated in Ang-(1-7)-treated LPS rats. Our results suggest that Ang-(1-7) ameliorates endotoxaemic-induced organ injury and platelet dysfunction, likely through the inhibition of the inflammatory response and nitric oxide production.

Hypertonic saline, mannitol and hydroxyethyl starch preconditioning of platelets obtained from septic patients attenuates CD40 ligand expression in vitro.

BACKGROUND: Because platelet CD40 ligand (CD40L) expression plays an important role in inflammatory conditions, reduction of CD40L expression may be beneficial for patients with sepsis. Although hypertonic saline, mannitol, and hydroxyethyl starch (HES) solutions have been shown to modulate inflammatory responses, their effects on platelet CD40L expression are unclear. We assessed the effects of hypertonic saline, mannitol, and HES solutions on platelet CD40L expression. METHODS: Platelet-rich plasma samples were obtained from septic patients and diluted to 1%, 2.5%, 5%, or 7.5% (vol/vol) with 7.5% saline, 3% saline, 0.9% saline, 20% mannitol, 10% HES (200/0.5), or Ringer's solution. Twenty-five samples were used per dilution. To determine platelet CD40L expression, platelet samples were stimulated with thrombin (0.1 U/mL), incubated with fluorochrome-conjugated platelet antibodies, and analyzed using flow cytometry. RESULTS: Preconditioning of platelet-rich plasma with hypertonic saline, mannitol, and HES attenuated CD40L expression at dilution ratios of 5%, 1%, and 1%, respectively. The decreases were concentration dependent. The effects of mannitol and HES on CD40L expression were almost identical and were superior to those of 3% saline. In contrast, 0.9% saline and Ringer's solution had no effect on CD40L expression. CONCLUSIONS: Our data show that resuscitation fluids, such as hypertonic saline, mannitol, and HES, inhibit agonist-induced CD40L expression on platelets. These resuscitation fluids may have an anti-inflammatory action when administered to septic patients.

Low-dose hydralazine improves endotoxin-induced coagulopathy and multiple organ dysfunction via its anti-inflammatory and anti-oxidative/nitrosative properties.

Coagulopathy is the major cause of organ injury as well as a strong predictor of mortality in septic patients. Systemic inflammatory response and redox imbalance are regarded as the major causes of sepsis-induced coagulopathy. There is growing evidence that a vasodilator hydralazine has beneficial effects on heart failure, hypertension, and ischemia/reperfusion injury via its antioxidant and anti-inflammatory properties. However, the effects of hydralazine on sepsis have not been examined. Therefore, we evaluated the effects of low-dose hydralazine on coagulopathy and multiple organ dysfunction in septic rats induced by endotoxin. Sepsis-induced coagulopathy was established by intravenous injection of rats with lipopolysaccharide (LPS). The changes of blood pressure, heart rate, blood glucose, hemostatic variables, prothrombin time, organ function indices, interleukin-6 (IL-6) concentration, and nitric oxide (NO) level were assessed during the experimental period. In addition, the aortas, lungs, livers, and kidneys were dissected to analyze superoxide levels and protein expressions. LPS induced (i) coagulopathy, multiple organ dysfunction, and circulatory failure successfully, and (ii) excessive superoxide, NO, and IL-6 production, accompanied by the overexpression of iNOS and Wnt5a in animals. Treatment of LPS-induced septic rats with low-dose hydralazine not only improved coagulopathy but also ameliorated multiple organ dysfunction. These could be due to attenuation of the overproduction of superoxide, NO, and IL-6, which were attributed to reduction of the overexpression of iNOS and Wnt5a. Thus, these findings indicate that low-dose hydralazine could be a potential therapy for sepsis-induced coagulopathy and multiple organ dysfunction via its anti-inflammatory and anti-oxidative/nitrosative properties.

Therapeutic effects of hypertonic saline on peritonitis-induced septic shock with multiple organ dysfunction syndrome in rats.

OBJECTIVE: Significant mortality in patients with sepsis results from the development of multiple organ dysfunction syndrome. Small-volume resuscitation with 7.5% NaCl hypertonic saline has been proposed to restore physiologic hemodynamics in hemorrhagic shock. Therefore, we hypothesized that hypertonic saline resuscitation could alleviate the development of multiple organ dysfunction syndrome in sepsis induced by cecal ligation and puncture. DESIGN: Randomized, prospective animal experiment. SETTING: Academic research laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: The animals were randomly allocated to one of four groups: 1) sham operation (0.9% NaCl, 4 mL/kg intravenously, at 3 hrs after laparotomy); 2) sham operation plus hypertonic saline (7.5% NaCl, 4 mL/kg intravenously, at 3 hrs after laparotomy); 3) cecal ligation and puncture (0.9% NaCl, 4 mL/kg intravenously, at 3 hrs after cecal ligation and puncture); and 4) cecal ligation and puncture plus hypertonic saline (7.5% NaCl, 4 mL/kg intravenously, at 3 hrs after cecal ligation and puncture). MEASUREMENTS AND MAIN RESULTS: Cecal ligation and puncture for 18 hrs was associated with circulatory failure (i.e., hypotension and vascular hyporeactivity to norepinephrine), multiple organ dysfunction syndrome (examined by biochemical variables and histologic studies), and 18-hr mortality. Hypertonic saline not only ameliorated the deterioration of hemodynamic changes but also attenuated neutrophil infiltration in the lung and the liver of septic animals. Hypertonic saline increased the survival rate at 9 and 18 hrs compared with the cecal ligation and puncture group. Moreover, hypertonic saline reduced plasma nitric oxide and interleukin-1beta and organ O2-* levels in rats that underwent cecal ligation and puncture. CONCLUSIONS: Hypertonic saline prevented circulatory failure, alleviated multiple organ dysfunction syndrome, and decreased the mortality rate in animals receiving cecal ligation and puncture. These beneficial effects of hypertonic saline may be attributed to reducing the plasma concentration of nitric oxide and interleukin-1beta as well as the organ O2-* level and decreasing lung neutrophil infiltration and liver necrosis. Our study suggests that hypertonic saline could be a potential and inexpensive therapeutic agent in the early sepsis of animals or patients.

Combined effects of propofol and dexamethasone on rats with endotoxemia.

OBJECTIVE: To clarify the effect of combined treatment with propofol and dexamethasone on hemodynamics, organ injury, and survival rate in rats with endotoxemia. DESIGN: Randomized, prospective animal experiment. SETTING: Academic research laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: Rats were divided into five groups: a control group, a group of conscious rats infused with Escherichia coli lipopolysaccharide, two groups of lipopolysaccharide rats treated with either propofol or dexamethasone, and a group of lipopolysaccharide rats with combined treatment of propofol and dexamethasone. MEASUREMENTS AND MAIN RESULTS: All hemodynamic and biochemical variables were measured during the 6-hr observation. Propofol plus dexamethasone attenuated hypotension and delayed hypoglycemia and metabolic acidosis caused by coadministration of E. coli lipopolysaccharide. In addition, propofol plus dexamethasone attenuated the lipopolysaccharide-induced multiple organ dysfunctions, such as lung, liver, and kidney. The increases in serum tumor necrosis factor-alpha, tissue nitric oxide, and superoxide anion levels were attenuated by propofol plus dexamethasone in lipopolysaccharide rats. Microscopic findings confirmed that propofol plus dexamethasone attenuated the substantial swelling and cell infiltration in lung and kidney caused by endotoxin. The 22-hr survival rate after endotoxin injection was markedly increased in lipopolysaccharide rats with combined treatment compared with the lipopolysaccharide rats (80% vs. 0%). CONCLUSIONS: The combined treatment with propofol plus dexamethasone reduced mortality rate and attenuated organ injury in conscious rats treated with lipopolysaccharide. These protective effects may be associated with their anti-inflammatory capacity and antioxidant activity.

Therapeutic effects of melatonin on peritonitis-induced septic shock with multiple organ dysfunction syndrome in rats.

The pathogenesis of multiple organ dysfunction syndrome (MODS) in septic shock is complicated and not fully understood. Some studies show that an overproduction of nitric oxide (NO) leads to the refractory hypotension and multiple organ failure, while other studies suggest that free radicals, e.g. superoxide (O(2)(-)), contribute to the detrimental effect on vascular responsiveness and tissue/organ damage. Thus, this study was performed on the Wistar rat by using cecal ligation and puncture (CLP) to induce septic shock-associated MODS. We evaluated the effect of an antioxidant melatonin in CLP-induced septic rats and demonstrated that melatonin (3 mg/kg, i.v. at 3, 6, 12 hr after CLP) significantly (a) attenuated hyporeactivity to norepinephrine and delayed hypotension, (b) reduced plasma index of hepatic and renal dysfunction, (c) diminished plasma NO and interleukin-1beta (IL-1beta) concentrations as well as aortic O(2)(-) levels, (d) reduced marked infiltration of polymorphonuclear neutrophils (PMNs) in the lung and liver tissues, and (e) promoted the survival rate at 18 hr to twofold compared with the CLP alone group. The current study underlined the inhibition of plasma NO and IL-1beta as well as aortic O(2)(-) production and the reduction of PMN infiltration may lead to the amelioration of MODS, which may contribute to the beneficial effect of antioxidants (e.g. melatonin in this study) in conscious rats with peritonitis-induced lethality. Thus, the antioxidant could be a novel agent for the treatment of septic animals or patients in the early stage.

Macrophage expression of E3 ubiquitin ligase Grail protects mice from lipopolysaccharide-induced hyperinflammation and organ injury.

Multiple organ dysfunction caused by hyperinflammation remains the major cause of mortality during sepsis. Excessive M1-macrophage activation leads to systemic inflammatory responses. Gene related to anergy in lymphocytes (Grail) is regarded as an important regulator of T cells that functions by diminishing cytokine production. However, its role in regulating macrophage activation and organ injury during sepsis remains unclear. Our aim was to examine the effects of Grail on macrophage reactivity and organ injury in endotoxemic animals. Wild-type and Grail knockout mice were injected with vehicle or Escherichia coli lipopolysaccharide and observed for 24 h. Changes in blood pressure, heart rate, blood glucose, and biochemical variables were then examined. Moreover, levels of neutrophil infiltration, MMP-9, and caspase 3 were analyzed in the lungs of animals. The expression of pro-inflammatory cytokines in J774A, RAW264.7, and primary peritoneal macrophages stimulated with LPS were also assessed in the presence or absence of Grail. Results indicated that loss of Grail expression enhances the induction of pro-inflammatory cytokines in J774A, RAW264.7, and primary peritoneal macrophages treated with LPS. Furthermore, LPS-induced macrophage hyperactivation was alleviated by ectopic Grail overexpression. In vivo studies showed that Grail deficiency exacerbates organ damage in endotoxemic animals. Levels of neutrophil infiltration, MMP-9, and caspase 3 were significantly increased in the lungs of Grail-deficient endotoxemic mice. Thus, these results suggest that Grail contributes to the attenuation of hyperinflammation caused by activated macrophages and prevents organ damage in endotoxemic mice. We suggest that Grail signaling could be a therapeutic target for endotoxemia.

Role of activating transcription factor 3 in fructose-induced metabolic syndrome in mice.

Activating transcription factor 3 (ATF3) has been implicated in cardiovascular disease and inflammation. This study examined the effects of ATF3 knockout (KO) on blood pressure, glucose intolerance, dyslipidemia, inflammation, and visceral adiposity in mice fed who did and did not consume a high-fructose diet. Male mice were divided into four groups (N = 15 for each group): the Con (control) group (wild-type mice fed a standard chow diet), Fru group (wild-type mice fed a high-fructose [60% fructose] diet), ATF3KO-Con group (ATF3 KO mice fed a standard chow diet), and ATF3KO-Fru group (ATF3 KO mice fed a high-fructose [60% fructose] diet). Experiments were conducted for 8 weeks. Our data demonstrated that ATF3 KO mice have lower systolic blood pressure (SBP) levels than do wild-type mice, and that high-fructose diets increase SBP levels in both wild-type and ATF3 KO mice. ATF3 KO in mice increased the serum levels of glucose, insulin, triglycerides, tumor necrosis factor-alpha, and intercellular adhesion molecule-1, impaired endothelium-dependent aortic relaxation, increased aorta wall thickness and lipid peroxide, and expanded visceral adiposity. These symptoms resembled those exhibited by the wild-type mice fed a high-fructose diet, which caused hyperglycemia, insulin resistance, dyslipidemia, endothelium-dependent aortic dysfunction, inflammation, aorta remodeling, and visceral adiposity. A high-fructose diet among ATF3 KO mice deteriorated metabolic parameters and inflammatory cytokines. The present results therefore suggest that ATF3 deficiency is involved in the pathogenesis of metabolic syndrome and ATF3 might have a therapeutic role in fructose-induced impairment of endothelium-dependent aortic relaxation, a rising of inflammatory cytokines, and metabolic syndrome.