Effects of post-treatment with direct hemoperfusion using a CTR column on mortality and inflammatory responses to endotoxin-induced shock in rats

BACKGROUND: To clarify the effects of post-treatment with direct hemoperfusion using a CTR column on the mortality and inflammatory responses to endotoxin-induced shock in rats. METHODS: Thirty-six male rats were randomly assigned to 1 of 3 groups (n = 12/group): the endotoxemic group, receiving intravenous Escherichia coli endotoxin (15 mg/kg over 2 min); the control column group, treated without CTR for 120 min at 2 h after endotoxin injection, and CTR-post-treatment group, treated with CTR for 120 min at 2 h after endotoxin injection. Hemodynamics, arterial blood gases, and mortality were recorded for the 8-hour observation period, and plasma cytokine concentrations were measured every 4 h. RESULTS: The mortality rates were 83, 83 and 33% for the endotoxemic, control column, and CTR post-treatment groups, respectively. The increases in IL-6 concentrations were less for the CTR post-treatment group than the other 2 groups. CONCLUSION: The present study shows that CTR post-treatment inhibited hypotension and elevations in IL-6 concentrations, reducing the mortality rate of rats with endotoxin-induced shock.     

Elimination of endotoxin from the blood by extracorporeal activated charcoal hemoperfusion in experimental canine endotoxin shock

Circulating endotoxin is an important factor in the pathogenesis and clinical symptoms of endotoxin shock. The effect of extracorporeal activated charcoal hemoperfusion was investigated in experimental endotoxin shock of dogs produced by i.v. injection of Escherichia coli 089 endotoxin (1 mg/kg body weight). The endotoxin was labeled with 99mTc. The aorta and vein cava caudalis of anesthetized dogs were cannulated through the arteria and vein femorales. The cannulae were contacted to the hemoperfusion charcoal cartridge. The efficiency of hemoperfusion was tested from the blood samples, and the endotoxin content of blood was measured biologically (in lead acetate-treated rats) and isotopically (99mTc radioactivity) at 15, 30, 60, 90, and 120 min after injection. It was demonstrated that extracorporeal activated charcoal hemoperfusion can eliminate the majority of circulating endotoxin from the blood within 30 min.     

Blood purification for critical illness: cytokines adsorption therapy

Blood purification therapies have been clinically applied to treat cytokine-induced pathological effects. The effects of broad-spectrum adsorption using Lixelle (beta2-microglobulin adsorption column; Kaneka Corporation, Osaka, Japan) for the condition of hypercytokinemia in vitro, in an animal model and in humans with sepsis were investigated. We found that Lixelle could selectively adsorb not only beta2-microglobulin but also cytokines composed of glycoproteins in vitro. In addition, Lixelle beads could adsorb not only endotoxin (ET) but also microbial fragments such as peptidoglycan (PG) which is a component of Gram-positive bacteria. Hypercytokinemic rats were connected to a direct hemoperfusion (DHP) system using a mini Lixelle column and time-course changes in plasma levels of inflammatory cytokines were examined. In addition, a Lixelle column was used in direct hemoperfusion in patients with systemic inflammatory response syndrome (SIRS), and the relationship between a decrease in cytokines and clinical course was examined. The increases in plasma levels of IL-6 and tumor necrosis factor-alpha (TNF-alpha) were significantly inhibited in the group treated with the Lixelle column in an animal model. In humans with sepsis, for IL-1beta, IL-1Ra, IL-6, IL-8, and TNF-alpha, the adsorbing rates in vivo before and after the use of the Lixelle column tended to decrease with time. However, the reduction rates at 5 min after the start were 31.4, 39.3, 36.4, 76.2 and 71.6%, respectively, and at 3 h after the start, the rates were 18.0, 17.7, 12.9, 31.8, and 32.9%, respectively. Clinically, their blood pressure increased and they recovered from shock status. These results suggest that SIRS and sepsis with hypercytokinemia can be treated with the DHP using the Lixelle column.     

Direct Hemoperfusion With a β2-Microglobulin-selective Adsorbent Column Eliminates Inflammatory Cytokines and Improves Pulmonary Oxygenation

Abstract: Acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) are characterized by a high mortality rate; therefore, ARDS/ALI in humans is a leading cause of morbidity and mortality in critically ill patients. As previously reported, cytokines play a critical role as signaling molecules that initiate, amplify, and perpetuate inflammatory responses on a local and systemic basis, and the polymyxin-B immobilized direct hemoperfusion system (PMX–DHP) is effective for the treatment of ARDS/ALI. Furthermore, another direct hemoperfusion system using the β2-microglobulin-selective adsorbent column, Lixelle, the direct hemoperfusion treatment (Lixelle–DHP), has been applied in some cases to patients who are affected with systemic inflammatory response syndrome. The aim of this study is to evaluate the therapeutic efficacy of Lixelle–DHP in the treatment of ARDS/ALI. Four patients, aged 67–79 years old (mean 72 ± 6.2 years), diagnosed with ARDS/ALI were treated with Lixelle–DHP. The P_aO₂/fraction of inspired oxygen (F_iO₂) ratio (PF ratio) was 90.0 ± 22.9 before the treatment, and it increased to 129.9 ± 5.6 at 72 h afterward the start of treatment. Inflammatory cytokines such as interleukin (IL)-1β, IL-6, soluble intercellular adhesion molecule 1 (sICAM-1) decreased significantly after the treatment. All patients were still alive after one month. However, while IL-2 had decreased significantly after the treatment, it had returned by the next treatment. It is possible that Lixelle–DHP might be able to improve the PF ratio and mortality rate as a result of decreased cytokines, and it has been suggested that Lixelle–DHP has a beneficial influence in the treatment of ARDS/ALI.     

Changes of inflammation-associated cytokine expressions during early phase of experimental endotoxic shock in macaques

AIM: To study changes of inflammation-associated cytokine expressions during early phase of endotoxic shock in macague. METHODS: Experiments were performed in Macaque mulatta treated with LPS 2.8 mg/kg in shock model group or with normal saline in control group. Blood samples were collected before, or 60 min, or 120 min after LPS injection, respectively. Liver and spleen tissues were obtained at 120 min after LPS injection. The plasma levels of TNF-α,IL-1 β, IL-10 and IL-12P40 were determined by double-antibody sandwich ELISA with antibodies against human cytokines. The mRNA levels of TNF-α, IL-1 β, and IL-18 in peripheral blood mononuclear cells (PBMCs), liver and spleen were examined by real-time fluorescence semi-quantitative RT-PCR with the primers based on human genes. RESULTS: Mean systemic arterial pressure (MAP), systemicvascular resistance index (SVRI) and left ventricular work index (LVWI) of macaques were significant declined in shock model group on average 60 min after LPS injection. The plasma levels of TNF-α and IL-10 were significantly increased 60 min after LPS injection and then decreased. The plasma levels of IL-1 β and IL-12P40 were significantly increased at 120 min after LPS injection. The mRNA levels of TNF-α and IL-1 β were significantly increased 60 min after LPS stimulation in PBMCs and 120 min after LPS stimulation in livers. The mRNA level of IL-18 was significantly increased 120 rain after LPS stimulation in PBMCs and livers. But in spleen, only TNF-α mRNA level in LPS group was significantly higher 120 min after LPS stimulation, compared with that in control group. CONCLUSION: An endotoxic shock model of Macaque mulatta was successfully established. Both antibodies for ELISA and PCR primers based on human cytokine assays were successfully applied to detect macaque cytokines. In the model, inflammatory cytokines, such as TNF-α, IL-1 β,IL-12 and IL-18 as well as anti-inflammation cytokine IL-10, were released at very early phase of endotoxic shock within 120 min after LPS injection. PBMCs and liver cells might be the important sources of these cytokines.     

Effects of a new extracorporeal system using CTR on mortality and inflammatory responses to bacterial toxin-induced multiple organ dysfunction syndrome in rabbits

BACKGROUND/AIMS: In the pathogenesis of multiple organ dysfunction syndrome (MODS) caused by bacterial infection, a complex series of systemically secreted bacterial toxins and cytokines are intensely associated. Our previous study demonstrated that a new adsorbent, CTR, was capable of removing cytokines and toxic shock syndrome toxin-1 (TSST-1) in vitro. Moreover, extracorporeal treatment with CTR reduced the high mortality rate and inhibited inflammatory responses in endotoxin-induced shock in rats. However, it is unclear whether CTR treatment will be an effective therapy for MODS. Here, we demonstrated the efficacy of a new extracorporeal system using CTR on MODS induced by bacterial toxins in rabbits. METHODS: Direct hemoperfusion (DHP) apheresis with or without CTR for 120 min was performed in rabbits that had been intravenously infused with endotoxin and TSST-1. The mean arterial pressure was recorded and the plasma toxin and cytokine concentrations were measured during the treatment period. Mortality was assessed up to 7 days after exposure to the toxins. In addition, tissues specimens were examined using microscopy. RESULTS: The mortality rates at 7 days after the injection of the toxins were 90 and 10% for the control and CTR groups, respectively. The plasma concentrations of TSST-1, tumor necrosis factor and interleukin-1 beta in the CTR group were significantly lower than those in the control group. Histopathological examination revealed that tissue damage, such as necrosis and depletion of lymphocytes in the spleen and mesenteric lymph node, was reduced in the CTR group, compared with that in the control group, at 24 h after toxin infusion. CONCLUSION: The new adsorbent CTR improved the mortality rate in a MODS rabbit model by adsorbing TSST-1 and cytokines. Further development of CTR may expand the scope of extracorporeal therapies for patients with MODS.     

Effect of the thrombolytic agent, streptokinase, on the responses to endotoxemia in conscious rats

The potential role of coagulation defects as a pathologic mediator in septic shock is well documented, especially as it relates to increased thromboxane formation, thrombocytopenia, and disseminated intravascular coagulation. The present study was designed to determine the effect of the thrombolytic agent streptokinase on the sequelae of endotoxemia in the rat. Conscious male Sprague-Dawley rats were given a bolus intravenous dose of Salmonella enteritidis endotoxin (20 mg/kg; LD90 dose) 5 min after the intravenous administration of streptokinase (10,000 U/kg bolus + 1,000 U/kg/hr infusion), or heparin (100 U/kg bolus + 30 U/kg/hr infusion). The effects of streptokinase or heparin on blood clotting were determined by measuring ex vivo clot formation 1 hr after the administration of endotoxin. In naive and endotoxemic animals, both agents significantly reduced clot formation (P less than 0.05). In endotoxemic animals, streptokinase or heparin improved survival to 70%, compared to 8% survival in the endotoxin + vehicle group (P less than 0.05). The improvement in survival with streptokinase was dose-dependent. Neither streptokinase nor heparin prevented the thrombocytopenia or hemoconcentration which developed in endotoxemic animals. These results demonstrate the potential utility of streptokinase for improving survival in endotoxemia and further confirm the deleterious contribution of coagulation disorders in endotoxic mortality.     

Indomethacin treatment in newborn canine endotoxic shock

Prostaglandins have been reported to play an important role in endotoxic shock. However, the beneficial effects of prostaglandin synthesis inhibitors for the treatment of newborn endotoxic shock have been controversial. This study was performed to evaluate the effects of indomethacin on the hemodynamics during fulminant endotoxic shock in newborn dogs. After E. coli lipopolysaccharide (LPS) injection, mean arterial pressure was maintained for the first 60 min, and then declined from 53 +/- 2 to 27 +/- 2 mmHg at 120 min. Cardiac output dropped from 0.37 +/- 0.03 to 0.24 +/- 0.03 L/min/kg 5 min after LPS injection and continued to decline to 0.12 +/- 0.01 L/min/kg at 120 min. Indomethacin treatment 20 min prior to LPS injection attenuated the hypotension (50 +/- 3 mmHg at 120 min, p less than 0.05) and the decrease of cardiac output (0.18 +/- 0.02 L/min/kg at 120 min, p less than 0.05). Indomethacin treatment 5 min after LPS injection also attenuated the hypotension (55 +/- 4 mmHg at 120 min, p less than 0.05) and the decrease of cardiac output (0.21 +/- 0.02 L/min/kg at 120 min, p less than 0.05). Survival times were increased by the indomethacin treatments. Thus, indomethacin appears to be beneficial for the treatment of fulminant hemodynamic deterioration in newborn endotoxic shock.     

Effects of naloxone and thyrotropin-releasing hormone on plasma catecholamines, corticosterone, and arterial pressure in normal and endotoxemic rats

To investigate the possible involvement of the adrenal cortex and medulla in the cardiovascular effects of naloxone and thyrotropin-releasing hormone (TRH) in endotoxic shock, plasma epinephrine, norepinephrine, dopamine, and corticosterone were measured along with hemodynamic variables during naloxone and TRH treatment of normal and endotoxemic rats. In the absence of endotoxemia, naloxone (3 mg/kg, iv) did not significantly alter mean arterial pressure or plasma catecholamine or corticosterone levels. In contrast, following TRH administration (4 mg/kg, iv), an increase in mean arterial pressure was associated with significant increases in plasma epinephrine, norepinephrine, and corticosterone. TRH also produced a transient increase in plasma glucose levels. Endotoxic shock was associated with marked increases in plasma catecholamine levels, with epinephrine levels showing the greatest change, and significant though less pronounced increases in corticosterone. Both naloxone and TRH significantly elevated mean arterial pressures of endotoxemic rats, although neither of these compounds significantly altered the plasma catecholamine and corticosterone responses to endotoxin. Naloxone and TRH also failed to alter endotoxin-induced changes in plasma glucose levels. These results indicate that the cardiovascular effects of naloxone and TRH in endotoxic shock do not simply arise from an enhancement of adrenal catecholamine or corticosterone secretion.     

Resistance of essential fatty acid-deficient rats to endotoxic shock.

The role of lipids in the altered energy metabolism of shock remains to be delineated fully. During the course of our studies of endotoxic shock, the susceptibility of essential fatty acid (EFA)-deficient rats to endotoxin was evaluated. Intravenous administration of S. Salmonella enteritidis endotoxin (1 mg/100 gm) in normal male Long-Evans rats (7--8 weeks old) produced severe shock with an 88% mortality. In marked contrast, injection of this dose of endotoxin in EFA-deficient rats of the same age resulted in only an 18% mortality. The deficient state afforded significant protection to even supralethal doses of endotoxin (2 mg/100 gm). Evaluation of reticuloendothelial (RE) phagocytic activity with colloidal carbon did not reveal significant differences in RE clearance rates. Within five hours after induction of shock, however, plasma acid hydrolase activity of shocked control rats was approximately double that of the EFA-deficient group. Likewise, the endotoxin induced hypoglycemic response was milder in the EFA-deficient rats. The lower plasma glutamic-oxaloacetic transaminase activity and glutamic-pyruvic transaminase activity of the EFA-deficient group also indicated a maintenance of hepatic integrity. These observations suggest that essential fatty acids of their products (ie, prostaglandins) contribute to the pathogenesis of endotoxic shock.     

Protective effects of isohelenin,an inhibitor of nuclear factor kappaB,in endotoxic shock in rats

Recent in vitro studies have shown that isohelenin, a sesquiterpene lactone, inhibits the NF-kappaB pathway. This study examines the effect of isohelenin in endotoxic shock induced by administration of Escherichia coli endotoxin in male Wistar rats. A group of rats received isohelenin (2 mg/kg intraperitoneally) 15 min before endotoxin. In vehicle-treated rats, administration of endotoxin caused severe hypotension, which was associated with a marked hyporeactivity to norepinephrine and acetylcholine in ex vivo aortas. Elevated levels of plasma nitrate/nitrite, metabolites of nitric oxide (NO), were also found. These inflammatory events were preceded by cytosolic degradation of inhibitor-kappaBalpha (IkappaBalpha) and activation of nuclear factor-kappaB (NF-kappaB) in the lung within 15 min of endotoxin administration. Treatment with isohelenin resulted in hemodynamic improvement and reduced plasma levels of NO metabolites. Nuclear translocation of NF-kappaB was inhibited by isohelenin treatment in the lung, whereas degradation of IkappaBalpha was unchanged. In a separate set of experiments, treatment with isohelenin significantly improved survival in mice challenged with endotoxin. We conclude that isohelenin exerts beneficial therapeutic effects during endotoxic shock through inhibition of NF-kappaB.     

Effect of alpha-adrenergic blockage on cellular Ca2+ during endotoxic shock.

The effect of alpha-adrenergic receptor antagonists, phentolamine, and prazosin on cytosolic Ca2+ concentration, [Ca2+]i, was studied in hepatocytes during endotoxic shock. Rats were given intravenous injections of endotoxin (20 mg/kg), phentolamine (3 mg/kg) plus endotoxin (20 mg/kg), or prazosin (5 mg/kg) plus endotoxin (20 mg/kg). They were sacrificed 5 hr later, at which time the endotoxin-injected rats showed signs of shock. Isolated hepatocytes were prepared and employed for the measurement of [Ca2+]i under basal and hormone-stimulated (1 and 10 microM epinephrine) conditions by means of Quin 2 fluorescence technique. The apparent basal level of [Ca2+]i in endotoxic rat hepatocytes (mean +/- SE: 482 +/- 31 nM) was significantly higher (P less than 0.05) than in phentolamine plus endotoxin (242 +/- 73) and prazosin plus endotoxin (240 +/- 43) groups. A significant increase in hepatocyte [Ca2+]i occurred with epinephrine in the phentolamine plus endotoxin and prazosin plus endotoxin groups, but not in the group receiving endotoxin alone. Endotoxic rats showed a mortality rate of 75%, whereas phentolamine plus endotoxin and prazosin plus endotoxin groups showed a mortality rate of 38% and 20% respectively. These data suggest that the protective effect of alpha-adrenergic receptor antagonists during endotoxic shock may be mediated, in part, by attenuating the entrance of Ca2+ into endotoxic liver cells.     

Diltiazem treatment in newborn canine endotoxic shock

The mortality of sepsis/septic shock continues to be high in newborns. However, there is no established method in its treatment. Although calcium channel blockers ameliorate the hemodynamic deterioration of adult circulatory shock, their effects on newborn endotoxic shock have not been elucidated. This study was performed in newborn dogs to investigate the effects of diltiazem on newborn endotoxic shock. Endotoxic shock was induced in newborn dogs (2-10 days old, 300-800 g) by an intravenous injection of E. coli lipopolysaccharide (LPS; 1.5 mg/kg), and diltiazem (DZ) at the dose of 300, 600 or 1200 micrograms/kg was administered intravenously 20 min prior to LPS injection. Hemodynamic changes were serially observed until 120 min after LPS injection. The heart rate, mean arterial pressure and cardiac output decreased after LPS injection, and systemic vascular resistance decreased. DZ at the dose of 600 micrograms/kg attenuated the decreases of MAP and cardiac output, but 300 and 1200 micrograms/kg of DZ exacerbated them. DZ at the dose of 1200 micrograms/kg decreased the heart rate, and DZ at all three doses attenuated the increase of systemic vascular resistance. Therefore, 600 micrograms/kg of DZ is beneficial in the treatment of endotoxic shock in newborn dogs.     

Lung cyclic 3',5'-adenosine monophosphate and adenylate cyclase in endotoxic shock

Cyclic 3',5'-adenosine monophosphate (cyclic AMP) and adenylate cyclase activity were measured in lungs from guinea pigs in endotoxic shock induced by an intravenous injection of Salmonella enteritidis endotoxin (10 mg/kg body weight). Both cyclic AMP content and adenylate cyclase activity were significantly elevated in lung tissue from the endotoxic guinea pigs. There was no apparent change in the affinity of adenylate cyclase for its substrate (ATP); however, the maximum velocity of the enzyme reaction was increased in lungs from the endotoxic group. Endotoxin, in the concentration range of 10(-4) to 10(-2) micrograms/ml, added to lung homogenates did not affect adenylate cyclase activity. Prostaglandins do not seem to mediate the effects of endotoxin in vivo on lung cyclic AMP since treatment of guinea pigs with indomethacin (10 mg/kg body weight) 30 min prior to endotoxin administration did not alter the endotoxin-induced increase in lung cyclic AMP.     

Beta-adrenergic drug therapy in newborn canine endotoxic shock

The mortality of septic shock remains high in newborns. Although the effectiveness of adrenergic drug therapy continues to be controversial, adrenergic drugs have been used for the treatment of newborn endotoxic shock. To elucidate the effects of beta-adrenergic drugs on the fulminant hemodynamic deterioration of newborn endotoxic shock, newborn dogs (2-10-day-old, 264-800 g) were given Escherichia coli lipopolysaccharide (LPS; 10 mg/kg iv) and treated with isoproterenol (0.1 micrograms/kg/min) or dopamine (5 micrograms/kg/min) infusion from 5 to 120 min after LPS injection. Isoproterenol attenuated the effects of LPS by increasing the mean arterial pressure (32 +/- 2 vs. 13 +/- 1 mmHg at 120 min), cardiac output (183 +/- 29 vs. 118 +/- 23 ml/min/kg at 120 min), and the survival time (5.3 vs 2.9 hr). However, dopamine did not improve the hemodynamic deterioration. As dopamine-beta-hydroxylase activity in the blood was significantly lower in newborn dogs than in adult dogs, inadequate response of newborn dogs to dopamine was thought to be in part due to enzymatic immaturity.     

Contribution of platelet activating factor to hemodynamic and sympathetic responses to bacterial endotoxin in conscious rats

The effect of the platelet activating factor (PAF) antagonist WEB 2086 on blood pressure; heart rate; and plasma glucose, lactate, and catecholamine concentrations were examined following either PAF or endotoxin administration in conscious rats. PAF infusion (50 ng/kg/min for 60 min) resulted in a sustained hypotension, with tachycardia and elevated plasma norepinephrine (NE; 1.8-fold increase), epinephrine (E; 6.7-fold increase), and dopamine (DA; 1.0-fold increase) at 30 min after beginning infusion. Plasma NE, E, and DA became 4.1 (NE)-, 17.4 (E)-, and 3.3 (DA)-fold higher than control at 60 min after beginning infusion. Both the hemodynamic and plasma catecholamine alterations induced with PAF were completely blocked with WEB 2086 pretreatment. Bacterial endotoxin treatment (5 mg/kg, i.v. bolus) produced well-characterized responses of hypotension, tachycardia, hyperglycemia, hyperlactacidemia, and an elevation in plasma catecholamines. Whereas complete blockade of the hypotensive and tachycardic effect of endotoxin was achieved with WEB 2086 at 30 min following endotoxin, the increases in plasma catecholamines and lactate elicited by endotoxin were attenuated but remained significantly higher than control levels. Hyperglycemia following endotoxin was not altered by WEB 2086 treatment. In endotoxic rats pretreated with WEB 2086 there was significant hypotension, tachycardia, and hyperlactacidemia and an elevation in plasma catecholamines at both 60 and 120 min, but all were less severe compared to non-WEB 2086-treated endotoxic animals. The results demonstrate that WEB 2086 completely blocked early endotoxin-induced hypotension and tachycardia but not catecholamine elevation following endotoxin. This work suggests that sympathetic activation following endotoxin may be mediated by factors other than hypotension.     

Metabolic effects of insulin and insulin-like growth factor-I in endotoxemic rats during total parenteral nutrition feeding

The effects of insulin and insulin-like growth factor-I (IGF-I) on protein, energy, and glucose metabolism were examined in endotoxemic rats receiving total parenteral nutrition (TPN) for 3 days. The endotoxemic model was induced by constant infusion of lipopolysaccharide (1 mg/kg x d) for 3 days. The TPN regimen provided 200 kcal/kg x d and 1.5 g protein/kg x d. The dosage of insulin (5 mU/kg x h) and IGF-I (20 microg/kg x h), either alone or in combination, was chosen to maintain normal levels of leucine and glucose in plasma during feeding. One normal control and 4 endotoxemic groups with different treatments (saline, IGF-I, insulin, or IGF-I and insulin) were included. The effects of endotoxin were compared between the group receiving endotoxin alone and normal controls, and the effects of insulin and IGF-I were compared within the endotoxemic groups. The results show that endotoxin significantly increased the mortality and induced a hypermetabolic state, and nutrition alone could not overcome the catabolism induced by endotoxin. However, administration of insulin and IGF-I enhanced protein preservation in muscle tissue in endotoxemic rats during TPN. This effect was greater for insulin either alone or in combination with IGF-I. Insulin also significantly reduced the mortality. There were no additive effects of these two anabolic hormones on any measured parameter in these experimental conditions.     

Prednisolone inhibits endotoxin-induced disseminated intravascular coagulation and improves mortality in rats: importance of inflammatory cytokine suppression.

In order to determine whether prednisolone has a protective effect against the development of disseminated intravascular coagulation (DIC), we measured the effect of prednisolone on changes in hemostatic parameters and plasma levels of inflammatory cytokines in endotoxin-treated rats. Decreases in platelet count and fibrinogen levels, prolongation of prothrombin time, and increases in the plasma fibrin degradation products and levels of thrombin-antithrombin III (TAT) complex following the administration of endotoxin, all of which are associated with DIC, were significantly suppressed by the administration of prednisolone. Heparin administration significantly suppressed changes in all these parameters except for the decrease in platelet count. The combination of prednisolone and heparin was more effective than either treatment alone. In order to determine whether these effects of prednisolone are correlated with the suppression of inflammatory cytokine production, we examined the relationship between changes in plasma levels of cytokine, the hemostatic parameters listed above, and mortality using a number of intervention regimens designed to alter events of the experimentally induced DIC. Changes in hemostatic parameters associated with DIC following 30 mg/kg per 4 h of endotoxin infusion were significantly suppressed by treatment with 1 mg/kg prednisolone 30 min before beginning endotoxin infusion, followed by administration of 250 U/kg heparin 2 h after the start of endotoxin infusion (prednisolone-endotoxin-heparin regimen). The heparin and prednisolone were administrated subcutaneously. The administration of prednisolone and heparin in the reverse order (i.e. heparin first and prednisolone second: heparin-endotoxin-prednisolone regimen) also suppressed changes in hemostatic parameters, albeit to a smaller degree. Cytokine production was also significantly suppressed by the first treatment, but was not affected by the regimen in which heparin was administered first. Administration of prednisolone alone or heparin alone 30 min before endotoxin significantly reduced the number of renal glomeruli with fibrin thrombi. Plasma levels of creatinine and alanine transferase were reduced only by prednisolone. Increased plasma levels of interleukin-1beta, tissue necrosis factor-alpha and interleukin-6 were suppressed by prednisolone but not by heparin, and there were significant correlations between plasma levels of TAT and cytokines. Prednisolone was more effective than heparin in reducing mortality at 24 h after 100 mg/kg over 4 h of endotoxin infusion (four of 20 versus 15 of 20 deaths for prednisolone and heparin, respectively). These findings suggest that prednisolone inhibits the development of endotoxin-induced DIC and reduces mortality by a different mechanism than heparin, possibly through suppressing the production of inflammatory cytokines. Prednisolone may be efficacious in preventing DIC and multiple organ dysfunction caused by endotoxin.     

Changes in arterial hydrogen sulfide (H(2)S) content during septic shock and endotoxin shock in rats

OBJECTIVES: To explore the changes of hydrogen sulfide (H(2)S) in vascular tissues of rats with septic shock and endotoxin shock and its possible pathophysiological implication. METHODS: Rat models of septic shock induced by cecal ligation and puncture and of endotoxic shock induced by injection of endotoxin were used in this study. The authors measured hymodynamic variations, metabolic data, H(2)S and nitric oxide (NO) contents of different arteries in rats with septic shock and endotoxic shock. RESULTS: The results showed that hemodynamic parameters including the heart rate (HR), the mean arterial pressure (BP), and the +dP/dt max decreased markedly, while the left ventricular end-diastolic pressure (LVEDP) increased significantly and the rats developed hypoglycemia and lactic acidosis. Arterial H(2)S contents were significantly increased (P<0.01) in both septic and endotoxic shock (P<0.01). Endogenous H(2)S and NO contents all negatively correlated with BP, cardiac function and the degree of hypoglycemia (P<0.01). CONCLUSIONS: The results of our study demonstrated that endogenous vascular H(2)S increased in rats with septic shock and endotoxic shock. It was suggested that endogenous H(2)S was involved in physiological and pathophysiological process during shock.     

Benoxaprofen attenuation of lethal canine endotoxic shock

Our prior work demonstrated in a canine endotoxic shock model (LD100) that the cyclooxygenase inhibitor ibuprofen given 60 minutes after endotoxin administration could improve hemodynamics but not survival over control animals. The present study was designed to examine the effect of benoxaprofen, a dual lipoxygenase and cyclooxygenase inhibitor, in the same canine endotoxic model (LD100) and compare it to ibuprofen treatment. After thiopental anesthesia (25 mg/kg IV), animals were instrumented to measure various cardiovascular parameters. Endotoxic shock was induced by injecting Escherichia coli (0111:B4) endotoxin (1 mg/kg IV). Benoxaprofen (10 mg/kg IV; N = 13), ibuprofen (12.5 mg/kg; N = 6), or saline (N = 12) was injected 60 minutes after endotoxin administration. During the treatment period, both benoxaprofen and ibuprofen increased mean arterial pressure, heart rate, and vascular resistance to the same degree over the control animals. Benoxaprofen did increase dP/dtmax while ibuprofen did not. Twenty-four-hour survival was 0% for the control animals (N = 12), 0% for the ibuprofen group (N = 6), and 61.5% for the benoxaprofen group (N = 13). In an additional set of experiments, benoxaprofen (N = 8) was given 120 minutes after endotoxin administration and demonstrated similar improvements in hemodynamics and survival. These data demonstrate that benoxaprofen could improve survival in an otherwise lethal endotoxic model and suggest that the products of the lipoxygenase pathway may contribute to the lethality of an LD100 endotoxic shock model.