[Heart in sepsis : Molecular mechanisms, diagnosis and therapy of septic cardiomyopathy]. / Herz in der Sepsis : Molekulare Mechanismen, Diagnose und Therapie der septischen Kardiomyopathie.

An impairment of cardiac function is a key feature of cardiovascular failure associated with sepsis; however, its clinical relevance is still underestimated. Recent advancements in echocardiography in patients with septic shock enable a better characterization of septic cardiomyopathy by unmasking a severe, cardiac dysfunction even in the presence of preserved left ventricular ejection fraction. The pathophysiology of septic cardiomyopathy involves a complex mixture of systemic factors and molecular, metabolic, and structural changes of the cardiomyocytes. A better understanding of these factors will enable the discovery of new therapeutic targets for urgently needed disease-modifying therapeutic interventions. To date, the cornerstone of therapeutic management lies in control of the underlying infectious process and hemodynamic stabilization. This review summarizes the pathogenesis, diagnosis, and treatment of septic cardiomyopathy, and highlights the importance of further urgently needed studies aimed at improving diagnosis and treatment for septic cardiomyopathy.

A non-erythropoietic peptide derivative of erythropoietin decreases susceptibility to diet-induced insulin resistance in mice.

BACKGROUND AND PURPOSE: The haematopoietic activity of erythropoietin (EPO) is mediated by the classic EPO receptor (EpoR) homodimer, whereas tissue-protective effects are mediated by a heterocomplex between EpoR and the ß-common receptor (ßcR). Here, we investigated the effects of a novel, selective ligand of this heterocomplex - pyroglutamate helix B surface peptide (pHBSP) - in mice fed a diet enriched in sugars and saturated fats. EXPERIMENTAL APPROACH: Male C57BL/6J mice were fed a high-fat high-sucrose diet (HFHS) for 22 weeks. pHBSP (30 µg·kg(-1) s.c.) was administered for the last 11 weeks. Biochemical assays, histopathological and immunohistochemical examinations and Western blotting were performed on serum and target organs (liver, kidney and skeletal muscle). KEY RESULTS: Mice fed with HFHS diet exhibited insulin resistance, hyperlipidaemia, hepatic lipid accumulation and kidney dysfunction. In gastrocnemius muscle, HFHS impaired the insulin signalling pathway and reduced membrane translocation of glucose transporter type 4 and glycogen content. Treatment with pHBSP ameliorated renal function, reduced hepatic lipid deposition, and normalized serum glucose and lipid profiles. These effects were associated with an improvement in insulin sensitivity and glucose uptake in skeletal muscle. Diet-induced overproduction of the myokines IL-6 and fibroblast growth factor-21 were attenuated by pHBSP and, most importantly, pHBSP markedly enhanced mitochondrial biogenesis in skeletal muscle. CONCLUSIONS AND IMPLICATIONS: Chronic treatment of mice with an EPO derivative, devoid of haematopoietic effects, improved metabolic abnormalities induced by a high-fat high-sucrose diet, by affecting several levels of the insulin signalling and inflammatory cascades within skeletal muscle, while enhancing mitochondrial biogenesis.

Trauma alarmins as activators of damage-induced inflammation.

BACKGROUND: A systemic inflammatory response syndrome (SIRS) is frequently observed after traumatic injury. The response is sterile and the activating stimulus is tissue damage. Endogenous molecules, called alarmins, are reputed to be released by injured tissues but the precise identity of these mediators is unclear. This review summarizes current preclinical and clinical evidence for trauma alarmins and their role in innate immune activation. METHODS: A comprehensive literature review of putative alarmins in tissue damage after traumatic injury was conducted. RESULTS: The presence of SIRS at admission is an independent predictor of mortality after trauma. The primary initiators of the human immune response are unclear. Several endogenous substances display alarmin characteristics in vitro. Preclinical studies demonstrate that blockade of certain endogenous substances can reduce adverse clinical sequelae after traumatic injury. Human evidence for trauma alarmins is extremely limited. CONCLUSION: The magnitude of acute inflammation is predictive of outcome after trauma, suggesting that an early opportunity for immune modulation may exist. An understanding of the mechanisms of innate immune activation following trauma may lead to new therapeutic agents and improved patient survival.

Definition and drivers of acute traumatic coagulopathy: clinical and experimental investigations.

BACKGROUND: Acute traumatic coagulopathy (ATC) is an impairment of hemostasis that occurs early after injury and is associated with a 4-fold higher mortality, increased transfusion requirements and organ failure. OBJECTIVES: The purpose of the present study was to develop a clinically relevant definition of ATC and understand the etiology of this endogenous coagulopathy. PATIENTS/METHODS: We conducted a retrospective cohort study of trauma patients admitted to five international trauma centers and corroborated our findings in a novel rat model of ATC. Coagulation status on emergency department arrival was correlated with trauma and shock severity, mortality and transfusion requirements. 3646 complete records were available for analysis. RESULTS: Patients arriving with a prothrombin time ratio (PTr) > 1.2 had significantly higher mortality and transfusion requirements than patients with a normal PTr (mortality: 22.7% vs. 7.0%; P < 0.001. Packed red blood cells: 3.5 vs. 1.2 units; P < 0.001. Fresh frozen plasma: 2.1 vs. 0.8 units; P < 0.001). The severity of ATC correlated strongly with the combined degree of injury and shock. The rat model controlled for exogenously induced coagulopathy and mirrored the clinical findings. Significant coagulopathy developed only in animals subjected to both trauma and hemorrhagic shock (PTr: 1.30. APTTr: 1.36; both P < 0.001 compared with sham controls). CONCLUSIONS: ATC develops endogenously in response to a combination of tissue damage and shock. It is associated with increased mortality and transfusion requirements in a dose-dependent manner. When defined by standard clotting times, a PTr > 1.2 should be adopted as a clinically relevant definition of ATC.

GW0742, a high affinity PPAR-ß/δ agonist reduces lung inflammation induced by bleomycin instillation in mice.

Peroxisome Proliferator-Activated Receptor ß/δ belongs to a family of ligand-activated transcription factors. Recent data have clarified its metabolic roles and enhanced the potential role of this receptor as a pharmacological target. Moreover, although its role in acute inflammation remains unclear, being the nuclear receptor PPAR ß/δ widely expressed in many tissues, including the vascular endothelium, we assume that the infiltration of PMNs into tissues, a prominent feature in inflammation, may also be related to PPAR ß/δ. Mice subjected to intratracheal instillation of bleomycin (BLEO, 1 mg/kg), a glycopeptide produced by the bacterium Streptomyces verticillus, develop lung inflammation and injury characterized by a significant neutrophil infiltration and tissue oedema. Therefore, the aim of this study is to investigate the effects of GW0742, a synthetic high affinity PPAR ß/δ agonist, and its possible role in preventing the advance of inflammatory and apoptotic processes induced by bleomycin, that long-term leads to the appearance of pulmonary fibrosis. Our data showed that GW0742-treatment (0.3 mg/Kg, 10 percent DMSO, i.p.) has therapeutic effects on pulmonary damage, decreasing many inflammatory and apoptotic parameters detected by measurement of: 1) cytokine production; 2) leukocyte accumulation, indirectly measured as decrease of myeloperoxidase (MPO) activity; 3) IkBα degradation and NF-kB nuclear translocation; 4) ERK phosphorylation; 5) stress oxidative by NO formation due to iNOS expression; 6) nitrotyrosine and PAR localization; 7) the degree of apoptosis, evaluated by Bax and Bcl-2 balance, FAS ligand expression and TUNEL staining. Taken together, our results clearly show that GW0742 reduces the lung injury and inflammation due to the intratracheal BLEO--instillation in mice.

Role for endothelial nitric oxide synthase in nitrite-induced protection against renal ischemia-reperfusion injury in mice.

Nitrite is protective against renal ischemia/reperfusion injury (IRI); an effect due to its reduction to nitric oxide (NO). In addition to other reductase pathways, endothelial NO synthase (eNOS) may also facilitate nitrite reduction in ischemic environments. We investigated the role of eNOS in sodium nitrite (60 microM, 10 ml/kg applied topically 1 min before reperfusion)-induced protection against renal IRI in C57/BL6 wild-type (WT) and eNOS knockout (eNOS KO) mice subjected to bilateral renal ischemia (30 min) and reperfusion (24h). Markers of renal dysfunction (plasma [creatinine] and [urea]), damage (tubular histology) and inflammation (cell recruitment) were elevated following IRI in WT mice; effects significantly reduced following nitrite treatment. Chemiluminescence analysis of cortical and medullary sections of the kidney demonstrated rapid (within 1 min) distribution of nitrite following application. Whilst IRI caused a significant (albeit substantially reduced compared to WT mice) elevation of markers of renal dysfunction and damage in eNOS KO mice, the beneficial effects of nitrite were absent or reduced, respectively. Moreover, nitrite treatment enhanced renal dysfunction in the form of increased plasma [creatinine] in eNOS KO mice. Confirmation of nitrite reductase activity of eNOS was provided by demonstration of nitrite (100 microM)-derived NO production by kidney homogenates of WT mice, that was significantly reduced by L-NMMA. L-NMMA was without effect using kidney homogenates of eNOS KO mice. These results support a role for eNOS in the pathways activated during renal IRI and also identify eNOS as a nitrite reductase in ischemic conditions; activity which in part underlies the protective effects of nitrite.

Glycogen synthase kinase-3beta inhibition attenuates the development of bleomycin-induced lung injury.

Glycogen synthase kinase-3 (GSK-3) is an ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and has recently been implicated in the pathophysiology of a number of diseases. The aim of this study is to investigate the effects of TDZD-8, a potent and selective GSK-3beta inhibitor, on the development of lung injury caused by administration of bleomycin (BLM). Mice subjected to intra-tracheal administration of BLM developed significant lung injury characterized by marked neutrophil infiltration and tissue edema. An increase in immunoreactivity to nitrotyrosine, iNOS, TNF-alpha and IL-1beta was also observed in the lungs of BLM-treated mice. In contrast, administration of BLM-treated mice with TDZD-8 (1 mg/kg daily) significantly reduced (I) the degree of lung injury, (II) the increase in staining (immunohistochemistry) for myeloperoxidase (MPO), nitrotyrosine, iNOS, TNF-alpha and IL-1beta and (III) the degree of apoptosis, as evaluated by Bax and Bcl-2 immunoreactivity and TUNEL staining. Taken together, these results clearly demonstrate treatment with the GSK-3beta inhibitor TDZD-8 reduces the development of lung injury and inflammation induced by BLM in mice.

Inhibition of glycogen synthase kinase-3beta attenuates the development of carrageenan-induced lung injury in mice.

BACKGROUND AND PURPOSE: Glycogen synthase kinase-3 (GSK-3) is a ubiquitous serine-threonine protein kinase that participates in a multitude of cellular processes and has recently been implicated in the pathophysiology of a number of diseases. The aim of this study was to investigate the effects of GSK-3beta inhibition in a model of acute inflammation. Here, we have investigated the effects of TDZD-8, a potent and selective GSK-3beta inhibitor, in a mouse model of carrageenan-induced pleurisy. EXPERIMENTAL APPROACH: Injection of carrageenan into the pleural cavity of mice elicited an acute inflammatory response characterized by: accumulation of fluid containing a large number of neutrophils (PMNs) in the pleural cavity, infiltration of PMNs in lung tissues and subsequent lipid peroxidation, and increased production of nitrite/nitrate (NOx), prostaglandin E2 (PGE2), tumour necrosis factor-alpha, (TNF-alpha) and interleukin-1beta (IL-1beta). Furthermore, carrageenan induced an upregulation of the adhesion molecules ICAM-1 and P-selectin, iNOS, COX-2 as well as nitrotyrosine as determined by immunohistochemical analysis of lung tissues. KEY RESULTS: Administration of TDZD-8 (1, 3 or 10 mg kg(-1), i.p.), 30 min prior to injection of carrageenan, caused a dose-dependent reduction in all the parameters of inflammation measured. CONCLUSIONS AND IMPLICATIONS: Thus, based on these findings we propose that inhibitors of the activity of GSK-3beta, such as TDZD-8, may be useful in the treatment of various inflammatory diseases.

The production of hydrogen sulfide limits myocardial ischemia and reperfusion injury and contributes to the cardioprotective effects of preconditioning with endotoxin, but not ischemia in the rat.

We investigated whether (endogenous) hydrogen sulfide (H2S) protects the heart against myocardial ischemia and reperfusion injury. Furthermore, we investigated whether endogenous H2S is involved in the protection afforded by (1) ischemic preconditioning and (2) the second window of protection caused by endotoxin. The involvement of one of the potential (end) effectors of the cardioprotection afforded by H2S was investigated using the mitochondrial KATP channel blocker, 5-hydroxydecanoate (5-HD; 5 mg/kg). Animals were subjected to 25 min regional myocardial ischemia followed by reperfusion (2 h) and were pretreated with the H2S donor, sodium hydrosulfide (3 mg/kg i.v.). Animals were also subjected to shorter periods of myocardial ischemia (15 min) and reperfusion (2 h) and pretreated with an irreversible inhibitor of cystathionine-gamma-lyase, dl-propargylglycine (PAG; 50 mg/kg i.v.). Animals were also pretreated with PAG (50 mg/kg) and subjected to either (1) ischemic preconditioning or (2) endotoxin (1 mg/kg i.p.) 16 h before myocardial ischemia. Myocardial infarct size was determined by p-nitroblue tetrazolium staining. Administration of sodium hydrosulfide significantly reduced myocardial infarct size, and this effect was abolished by 5-HD. Administration of PAG (50 mg/kg) or 5-HD significantly increased infarct size caused by 15 min of myocardial ischemia. The delayed cardioprotection afforded by endotoxin was abolished by 5-HD or PAG. In contrast, PAG (50 mg/kg) did not affect the cardioprotective effects of ischemic preconditioning. These findings suggest that (1) endogenous H2S is produced by myocardial ischemia in sufficient amounts to limit myocardial injury and (2) the synthesis or formation of H2S by cystathionine-gamma-lyase may contribute to the second window of protection caused by endotoxin.

Cytokine responses to CpG DNA in human leukocytes.

Previous studies have implicated a role of bacterial DNA, containing unmethylated cytosine-phosphate-guanosine (CpG) motifs, in the initiation of systemic inflammation. This is based on the ability of CpG-DNA to act in synergy with lipopolysaccharide (LPS) to trigger tumor necrosis factor alpha (TNFalpha) production in murine monocytes and to enhance LPS toxicity in rodents. In this study we investigated the capacity of CpG-DNA to trigger and modulate cytokine responses in human leukocytes. A human blood assay, as well as isolated cultures of monocytes and neutrophils, was exposed to the synthetic oligodeoxynucleotides (ODNs) CpG ODN (2006) and GpC ODN (2006-GC), alone or in combination with peptidoglycan or LPS. Plasma or supernatants were isolated and analyzed for TNFalpha, interleukin-1 beta (IL-1beta), IL-6 and IL-8 by ELISA. In the blood, 2006 (but not 2006-GC) induced the release of TNFalpha (P < 0.05) and possibly IL-1beta and IL-6. IL-8 was induced in a CpG-independent manner. When co-administered with peptidoglycan, both ODNs enhanced the release of cytokines, but not consistently CpG dependent. When co-administered with LPS, only IL-8 values were enhanced, whereas IL-6 was suppressed at early time points. In monocyte and neutrophil cultures, CpG dependent induction of cytokine release was not observed. However, both ODNs inhibited LPS-induced IL-6. In conclusion, the capacity of CpG DNA to trigger the release of TNFalpha and to enhance LPS-induced release of this cytokine is confirmed in human whole blood, but not in adherent human monocytes. Most effects of the ODNs on cytokine release in human leukocytes were CpG independent.

Anti-inflammatory properties of enamel matrix derivative in human blood.

BACKGROUND AND OBJECTIVE: Enamel matrix derivative (EMD), extracted from porcine tooth buds, has been shown to promote periodontal healing in patients with severe periodontitis. This involves modulation of the inflammatory response followed by the onset of periodontal regeneration. Based on these observations, we examined the ability of EMD to modulate the release of a pro-inflammatory cytokine [tumor necrosis factor (TNF)-alpha], an anti-inflammatory cytokine (interleukin-10) and a chemokine (interleukin- 8) in whole human blood challenged by bacterial cell wall components. MATERIAL AND METHODS: Whole blood from healthy donors was challenged by lipopolysaccharide or peptidoglycan and incubated with different concentrations of EMD or a cAMP analogue 8-(4-chlorophenyl)thio-cAMP (8-CPT-cAMP). TNF-alpha, interleukin-8 and interleukin-10 were analysed from plasma by enzyme-linked immunosorbent assay (ELISA) while cAMP levels of peripheral blood mononuclear cell lysates were analysed by enzyme immunoassay (EIA). RESULTS: We found that EMD attenuated the release of TNF-alpha and interleukin-8 in whole blood from healthy donors challenged by lipopolysaccharide or peptidoglycan, while the release of interleukin-10 was unchanged. Enamel matrix derivative also produced a four-fold increase in the cAMP levels of peripheral blood mononuclear cell lysates. Like EMD, 8-CPT-cAMP attenuated the formation of TNF-alpha, but not of interleukin-10, in blood challenged by lipopolysaccharide. CONCLUSION: Enamel matrix derivative limits the release of pro-inflammatory cytokines induced by lipopolysaccharide or peptidoglycan in human blood, suggesting that it has anti-inflammatory properties. We propose that this effect of EMD is, at least partly, secondary to an increase in the intracellular levels of cAMP in peripheral blood mononuclear cells.

Peptidoglycan of Staphylococcus aureus upregulates monocyte expression of CD14, Toll-like receptor 2 (TLR2), and TLR4 in human blood: possible implications for priming of lipopolysaccharide signaling.

Previous studies have indicated that peptidoglycan (PepG) from gram-positive bacteria can exert a priming effect on the innate immune response to lipopolysaccharide (LPS) from gram-negative bacteria. Here, we hypothesized that this priming effect may be preceded by enhanced expression of monocyte CD14, Toll-like receptor 2 (TLR2), and TLR4. In an ex vivo whole human blood model, we observed a substantial synergy between LPS and PepG in the release of tumor necrosis factor alpha and interleukin-1beta (IL-1beta) over the 24-h experimental period, whereas the effect on IL-8 and IL-10 release was more time dependent. The priming effect of PepG on cytokine release was preceded by a rapid upregulation of CD14, TLR2, and TLR4 expression on monocytes: at 3 hours there was a twofold increase in CD14 expression (P < 0.03), a fivefold increase in TLR2 expression (P < 0.03), and a twofold increase in TLR4 expression (P < 0.03). CD14 and TLR2 remained upregulated throughout the experimental period following exposure to PepG (P < 0.05). Only a transient upregulation of these monocyte receptors was observed following treatment with LPS or LPS plus PepG. In conclusion, the synergistic effect of LPS and PepG on cytokine release is preceded by a reciprocal upregulation of TLR2 and TLR4 by both bacterial cell wall components.

Effect of rosiglitazone and 15-deoxy-Delta12,14-prostaglandin J2 on bleomycin-induced lung injury.

Thiazolidinedione rosiglitazone and 15-deoxy-Delta12,14-prostaglandin J2 (15d-PGJ2), are two peroxisome proliferator-activated receptor (PPAR)-gamma ligands. The aim of this study was to investigate the effect of rosiglitazone and 15d-PGJ2 on the lung injury caused by bleomycin administration. Mice subjected to intratracheal administration of bleomycin developed significant lung injury. An increase in immunoreactivity to nitrotyrosine, poly(ADP ribose) polymerase (PARP) and inducible nitric oxide synthase as well as a significant loss of body weight and mortality was observed in the lung of bleomycin-treated mice. Administration of the two PPAR-gamma agonists rosiglitazone (10 mg x kg(-1) i.p.) and 15d-PGJ2 (30 microg x kg(-1) i.p.) significantly reduced the: 1) loss of body weight, 2) mortality rate, 3) infiltration of the lung with polymorphonuclear neutrophils (myeloperoxidase activity), 4) oedema formation, and 5) histological evidence of lung injury. Administration of rosiglitazone and 15d-PGJ2 also markedly reduced the nitrotyrosine, PARP and inducible nitric oxide synthase formation. In addition, treatment with the PPAR-gamma antagonist bisphenol A diglycidyl ether (1 mg x kg(-1) i.p. 30 min before the rosiglitazone or 15d-PGJ2) significantly antagonised the effect of the two PPAR-gamma agonists. These results demonstrate that the two peroxisome proliferator-activated receptor-gamma agonists, rosiglitazone and 15-deoxy-Delta12,14-prostaglandin J2, significantly reduce lung injury induced by bleomycin in mice.

Tempol, an intracelullar free radical scavenger, reduces liver injury in hepatic ischemia-reperfusion in the rat.

Liver ischemia is of clinical interest because of its role in liver failure and also hepatic graft rejection. The generation of reactive oxygen species contributes to the injury that follows ischemia-reperfusion. One therapy utilizes the administration of antioxidants; however, only limited experience suggests a potential benefit of systemic administration of these compounds. To overcome the limitations of these compounds, small molecules with improved cell membrane permeability characteristics and higher potency, such as tempol, are being tested in vivo. Tempol, a membrane-permeable radical scavenger, interferes with the formation or the effects of many radicals, including superoxide anions, hydroxyl radicals, and peroxynitrite. The aim of this study was to investigate the effects of tempol in an in vivo rat model of liver ischemia-reperfusion injury. Male Wistar rats were pretreated with tempol (30 mg/kg, i.v.) 5 minutes prior to liver ischemia (for 30 minutes) and reperfusion (for 2 hours). The liver injury was assessed by measuring serum levels of transaminases, lactate dehydrogenase, and gamma-glutamyl transferase. Tempol significantly mitigated the increase in transaminases, lactate dehydrogenase, and gamma-glutamyl transferase following liver ischemia-reperfusion, suggesting an improvement in liver function and resistance to injury.

Ligands of the peroxisome proliferator-activated receptor-gamma and heart failure.

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear hormone receptor superfamily of ligand-activated transcription factors that are related to retinoid, steroid and thyroid hormone receptors. The PPAR subfamily comprises of three members, PPAR-alpha, PPAR-beta and PPAR-gamma. There is good evidence that ligands of PPAR-gamma, including certain thiazolinediones, reduce myocardial tissue injury and infarct size. The use of PPAR-gamma agonists in the treatment of heart failure is, however, controversial.

The tyrosine kinase inhibitor tyrphostin AG 126 reduces the multiple organ failure induced by zymosan in the rat.

OBJECTIVE: To investigate the effects of tyrphostin AG 126, a tyrosine kinase inhibitor, on the multiple organ failure (MOF) caused by zymosan in the rat. DESIGN: Zymosan (500 mg/kg, suspended in saline solution, i.p.) causes an enhanced formation of reactive oxygen species, which contribute to the pathophysiology of MOF. After zymosan or saline administration, animals were monitored for 12 days. MEASUREMENTS AND RESULTS: Treatment of rats with tyrphostin AG 126 (10 mg/kg, 3 mg/kg or 1 mg/kg intraperitoneally, 1 h and 6 h after zymosan) attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan in a dose-dependent fashion. Tyrphostin AG 126 also attenuated the lung, liver, and intestinal injury (histology) as well as the increase in the levels of myeloperoxidase and malondialdehyde caused by zymosan in the lung, liver, and intestine. Immunohistochemical analysis for nitrotyrosine, poly (ADP-ribose) polymerase (PAR), iNOS, and COX-2 revealed a positive staining in lung, liver and intestine from zymosan-treated rats. The degree of staining for nitrotyrosine, PAR, iNOS, and COX-2 were markedly reduced in tissue sections obtained from zymosan-treated rats which had received tyrphostin AG 126. Furthermore, treatment of rats with tyrphostin AG 126 significantly reduced the production of peroxynitrite and of pro-inflammatory cytokines TNF-alpha and IL-1beta. CONCLUSIONS: This study provides the first evidence that the protein kinase inhibitor tyrphostin AG 126 attenuates the degree of MOF associated with zymosan-induced peritonitis in the rat.

A novel, potent and selective inhibitor of the activity of inducible nitric oxide synthase (GW274150) reduces the organ injury in hemorrhagic shock.

An enhanced formation of nitric oxide (NO) by the inducible NO synthase (iNOS) may contribute to the pathophysiology of hemorrhagic shock. This study investigates the effect of a novel, potent and selective inhibitor of iNOS activity (GW274150) on the circulatory failure and the organ injury and dysfunction associated with hemorrhagic shock in the anesthetised rat. Hemorrhage (sufficient to lower mean arterial blood pressure to 45 mmHg for 90 min) and subsequent resuscitation with shed blood resulted (within 4 h after resuscitation) in a delayed fall in blood pressure, renal and liver injury and dysfunction as well as the pancreatic injury. Pre-treatment of rats with GW274150 (5 mg/kg at 30 min prior to the onset of hemorrhage) attenuated the renal dysfunction as well as the liver and pancreatic injury caused by hemorrhage and resuscitation. Interestingly, GW274150 did not reduce the delayed fall in blood pressure associated with hemorrhagic shock. We propose that an enhanced formation of NO from iNOS contributes to the organ injury and dysfunction in hemorrhagic shock, and that highly selective inhibitors of iNOS activity, such as GW274150, may represent a novel therapeutic approach for the therapy of hemorrhagic shock.

5-aminoisoquinolinone, a potent inhibitor of poly (adenosine 5'-diphosphate ribose) polymerase, reduces myocardial infarct size.

This study investigates the effects of a novel, water-soluble inhibitor of the activity of poly (adenosine 5'-diphosphate ribose) polymerase, 5-aminoisoquinolinone [5-aminoisoquinolin-1(2H)-one], on (i) poly (adenosine 5'-diphosphate ribose) polymerase activity in rat cardiac myoblasts and (ii) the infarct size caused by regional myocardial ischaemia and reperfusion in the rat. Exposure of H9c2 cells to hydrogen peroxide (H2O2, 1 mM) caused a significant increase in poly (adenosine 5'-diphosphate ribose) polymerase activity and an 80-90% reduction in mitochondrial respiration (cellular injury). Pretreatment of these cells with 5-aminoisoquinolinone (0.003-1 mM) caused a concentration-dependent inhibition of poly (adenosine 5'-diphosphate ribose) polymerase activity (IC50: approximately 4.5 microM, n=6-9) and cell injury (EC50: approximately 4.45 microM, n=9). In a rat model of myocardial infarction, left anterior descending coronary artery occlusion (25 min) and reperfusion (2 h) resulted in an infarct size of 50+/-3%. Administration (1 min before reperfusion) of 5-aminoisoquinolinone reduced myocardial infarct size in a dose-related fashion. Thus, 5-aminoisoquinolinone is a potent inhibitor of poly (adenosine 5'-diphosphate ribose) polymerase activity in cardiac myoblasts and reduces myocardial infarct size in vivo.

Peptidoglycan primes for LPS-induced release of proinflammatory cytokines in whole human blood.

The pathophysiological mechanisms involved in mixed bacterial infections caused by gram-positive and gram-negative bacteria are largely unknown. The present study examines the potential interaction between lipopolysaccharide (LPS) and peptidoglycan (PepG) in the induction of the sepsis-associated cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and IL-10 in whole human blood. Plasma values of these cytokines were measured by enzyme immunoassays and a TNF bioassay. Co-administration of PepG (10 microg/mL) or muramyl dipeptide (MDP, 1 microg/mL) with LPS (10 ng/mL) caused significantly elevated values of TNF-alpha and IL-6 in the blood that could not be obtained by the sum of the values obtained by each stimulant alone, or by 3-fold higher doses of either bacterial component alone. This phenomenon was observed 1 h after stimulation, throughout the experimental period (24 h), and with different doses of LPS and PepG. In contrast, the release of IL-10 was not influenced by the co-administration of PepG or MDP with LPS. The TNF-alpha release induced by co-administration of LPS and PepG was abrogated after pretreatment with a monoclonal antibody against CD14 (18D11). Addition of PepG or MDP to whole blood caused a 2-fold increase in the surface expression of CD14 on monocytes, as measured by flow cytometry. In contrast, LPS caused decreased expression of this receptor. Our data suggest that PepG and MDP primes human whole blood leukocytes for LPS-induced release of proinflammatory cytokines. We speculate that synergy between PepG and LPS may contribute to the pathogenesis in sepsis caused by mixed bacterial infections.

High density lipoproteins reduce organ injury and organ dysfunction in a rat model of hemorrhagic shock.

High density lipoproteins (HDLs) inhibit the cytokine-induced expression of endothelial cell adhesion molecules both in vitro and in vivo. We examined the ability of HDLs to mediate a functional anti-inflammatory effect by measuring their ability to prevent neutrophil adhesion and transmigration in vitro. Treatment of human endothelial cell cultures with physiologic concentrations of HDLs inhibited neutrophil binding by 68 +/- 5.9% (mean and se, n=6, P<0.05) and neutrophil transmigration by 48.7 +/- 6.7% (n=8, P<0.05). We then examined the effect of HDLs on inflammatory infiltration and subsequent multiple organ dysfunction syndrome (MODS), associated with trauma in a rat model of hemorrhagic shock. Rats given human HDLs (80 mg apo A-I/kg, i.v.) 90 min after hemorrhage (which reduced mean arterial pressure to 50 mmHg) and 1 min before resuscitation showed attenuation of the increases in the serum levels of markers of MODS normally observed in this model. Severe disruption of the architecture of tissues and the extensive cellular infiltration into those tissues were also largely inhibited in animals that received HDLs. Human HDLs attenuate the MODS associated with ischemia and reperfusion injury after hemorrhagic shock in rats.