SIVELESTAT, A NEUTROPHIL ELASTASE INHIBITOR, ATTENUATES NEUTROPHIL PRIMING AFTER HEPATOENTERIC ISCHEMIA IN RABBITS

Ringer's ethyl pyruvate solution attenuates hypoperfusion and renal injury after multivisceral ischemia-reperfusion in rabbits

Ringer's ethyl pyruvate solution (REPS) has been protective against experimental renal, intestinal, and spinal ischemia and may be useful for organ protection in major vascular surgery. The purpose of this study was to investigate whether REPS attenuates organ injury in a rabbit model of supraceliac aortic cross-clamp that simulates thoracoabdominal aortic surgery. Following the Institutional Animal Care and Use Committee's approval, 20 rabbits were undergone cross-clamping of the supraceliac thoracic aorta for 30 min, and observed for 180 min after reperfusion. Either REPS (33 mg/kg/h of ethyl pyruvate) or Ringer's lactate solution were infused throughout the study period. Arterial pressure and aortic blood flow were continuously monitored. Blood lactate concentration, serum transaminase levels, neutrophil activation, and urinary N-acetyl-beta-glucosaminidase (NAG) activity were evaluated. After reperfusion, supraceliac aortic blood flow was significantly higher, and urinary NAG was significantly lower in animals that received REPS, while the other parameters were not significantly different. In conclusion, REPS attenuated the reduction of aortic blood flow and urinary NAG elevation after the cross-clamp of supraceliac aorta.

A Brief Period of Hypothermia Induced by Total Liquid Ventilation Decreases End-Organ Damage and Multiorgan Failure Induced by Aortic Cross-Clamping

BACKGROUND

In animal models, whole-body cooling reduces end-organ injury after cardiac arrest and other hypoperfusion states. The benefits of cooling in humans, however, are uncertain, possibly because detrimental effects of prolonged cooling may offset any potential benefit. Total liquid ventilation (TLV) provides both ultrafast cooling and rewarming. In previous reports, ultrafast cooling with TLV potently reduced neurological injury after experimental cardiac arrest in animals. We hypothesized that a brief period of rapid cooling and rewarming via TLV could also mitigate multiorgan failure (MOF) after ischemia-reperfusion induced by aortic cross-clamping.

METHODS

Anesthetized rabbits were submitted to 30 minutes of supraceliac aortic cross-clamping followed by 300 minutes of reperfusion. They were allocated either to a normothermic procedure with conventional ventilation (control group) or to hypothermic TLV (33°C) before, during, and after cross-clamping (pre-clamp, per-clamp, and post-clamp groups, respectively). In all TLV groups, hypothermia was maintained for 75 minutes and switched to a rewarming mode before resumption to conventional mechanical ventilation. End points included cardiovascular, renal, liver, and inflammatory parameters measured 300 minutes after reperfusion.

RESULTS

In the normothermic (control) group, ischemia-reperfusion injury produced evidence of MOF including severe vasoplegia, low cardiac output, acute kidney injury, and liver failure. In the TLV group, we observed gradual improvements in cardiac output in post-clamp, per-clamp, and pre-clamp groups versus control (53 ± 8, 64 ± 12, and 90 ± 24 vs 36 ± 23 mL/min/kg after 300 minutes of reperfusion, respectively). Liver biomarker levels were also lower in pre-clamp and per-clamp groups versus control. However, acute kidney injury was prevented in pre-clamp, and to a limited extent in per-clamp groups, but not in the post-clamp group. For instance, creatinine clearance was 4.8 ± 3.1 and 0.5 ± 0.6 mL/kg/min at the end of the follow-up in pre-clamp versus control animals (P = .0004). Histological examinations of the heart, kidney, liver, and jejunum in TLV and control groups also demonstrated reduced injury with TLV.

CONCLUSIONS

A brief period of ultrafast cooling with TLV followed by rapid rewarming attenuated biochemical and histological markers of MOF after aortic cross-clamping. Cardiovascular and liver dysfunctions were limited by a brief period of hypothermic TLV, even when started after reperfusion. Conversely, acute kidney injury was limited only when hypothermia was started before reperfusion. Further work is needed to determine the clinical significance of our results and to identify the optimal duration and timing of TLV-induced hypothermia for end-organ protection in hypoperfusion states.

3'-Daidzein sulfonate sodium improves mitochondrial functions after cerebral ischemia/reperfusion injury

3′-Daidzein sulfonate sodium is a new synthetic water-soluble compound derived from daidzein (an active ingredient of the kudzu vine root). It has been shown to have a protective effect on cerebral ischemia/reperfusion injury in rats. We plan to study the mechanism of its protective effect. 3′-Daidzein sulfonate sodium was injected in rats after cerebral ischemia/reperfusion injury. Results showed that 3′-daidzein sulfonate sodium significantly reduced mitochondrial swelling, significantly elevated the mitochondrial membrane potential, increased mitochondrial superoxide dismutase and glutathione peroxidase activities, and decreased mitochondrial malondialdehyde levels. 3′-Daidzein sulfonate sodium improved the structural integrity of the blood-brain barrier and reduced blood-brain barrier permeability. These findings confirmed that 3′-daidzein sulfonate sodium has a protective effect on mitochondrial functions after cerebral ischemia/reperfusion injury, improves brain energy metabolism, and provides protection against blood-brain barrier damage.

The Potential Effect of Epidural Anesthesia on Mesenteric Injury after Supraceliac Aortic Clamping in a Rabbit Model

BACKGROUND

Epidural anesthesia is known to increase blood flow by producing vasodilatation on mesenteric circulation. In this experimental study, we aim to examine the effect of epidural anesthesia on mesenteric ischemic-reperfusion (IR) injury induced by supracoeliac aortic occlusion in a rabbit model.

METHODS

Twenty-eight male white New Zealand rabbits were assigned into 4 separate groups, with 7 rabbits in each group: group I, control group; group II, IR-only group; group III, IR plus epidural anesthesia group; group IV, epidural anesthesia-only group. IR model was produced by clamping supraceliac aorta with an atraumatic vascular clamp for 60 min, followed by reperfusion for 120 min. An epidural catheter was placed via Th12-L1 intervertebral space by using open technique before aortic clamping in those assigned to epidural anesthesia. IR injury was assessed using blood markers interleukin-6 and IMA and tissue markers superoxide dismutase and malondialdehyde. Also histopathological examination was performed to evaluate the degree of injury.

RESULTS

All biochemical markers in group II were significantly elevated in comparison with the other 3 groups (p < 0.05). This was paralleled by a more severe histopathological injury in IR- only group (group II). The group receiving IR plus epidural anesthesia (group III) had lower biochemical marker levels as compared with the IR-only group (group II).

CONCLUSIONS

Mesenteric IR injury that can occur during abdominal aorta surgery can be reduced by epidural anesthesia, which is commonly used during or after major operations for pain control. Controlled clinical studies are required to evaluate these findings.

The effect of the neutrophil elastase inhibitor sivelestat on early injury after liver resection

BACKGROUND

The effects of sivelestat on endotoxin-induced lung injury, postperfusion lung injury, and ischemia-reperfusion are known, yet the benefits of sivelestat during liver surgery have yet to be elucidated. The aim of the present study was to assess the effects of sivelestat, with a focus on postoperative chemical data, in hepatectomized patients.

PATIENTS AND METHODS

A prospective clinical study was conducted in 50 patients undergoing hepatic resection. Patients were randomly assigned to receive Elaspol, sivelestat (ELP group, n = 25) or placebo (control group, n = 25). Perioperative blood chemistry values in both groups, including high-mobility group box 1 (HMGB1) and interleukin (IL)-6, were monitored.

RESULTS

The HMGB1 levels increased immediately after the operation (from the intraoperative period to the second postoperative day [POD]) in the control group. Compared to the control group, the levels of HMGB1 in the ELP group were significantly suppressed by the perioperative administration of sivelestat. At POD 1, the levels of IL-6 in the ELP group decreased more rapidly than those before the operation compared to the control group.

CONCLUSIONS

A human clinical study demonstrated the effect of polymorphonuclear leukocyte elastase inhibitor on the earliest markers of liver injury. The present study showed that patients who received sivelestat had reduced release of HMGB1, and that IL-6 levels decreased more rapidly in patients treated with sivelestat than in those who received the placebo. The most appropriate dose, timing, and duration of sivelestat in humans remain unclear; however, it may have therapeutic potential for various liver injuries.

Platelet adhesion in the sinusoid caused hepatic injury by neutrophils after hepatic ischemia reperfusion

Liver ischemia-reperfusion (I/R) injury is one of the most serious complications of hepatic surgery. In I/R, activated Kupffer cells cause platelet adhesion to sinusoidal endothelium as well as neutrophils and cause liver dysfunction. The aim of this study was to evaluate platelet dynamics in the hepatic microcirculation after I/R by intravital microscopy (IVM) and to clarify the relationship between platelet adhesion and neutrophil activation. Male Sprague-Dawley (SD) rats were divided into two groups: the control (administration of saline) group and the sivelestat group in which neutrophil activation was suppressed by sivelestat before I/R. The number of adherent platelets in sinusoid was observed up to 120 minutes after I/R by IVM. Samples of liver tissue and blood were taken for examination of histological findings, liver enzymes and inflammatory cytokines. The number of adherent platelets was significantly increased after I/R in both groups. Compared with the control group, the number of adherent platelets significantly decreased after hepatic I/R in the sivelestat group. Moreover, sivelestat improved changes of histological findings and elevation of liver enzymes. However, there was no significant difference in inflammatory cytokines of TNF-alpha, IL-1beta or IL-6. Platelet adhesion in the sinusoid is associated with liver dysfunction after I/R as well as neutrophils. Activated neutrophils induce platelet adhesion in the sinusoid of the liver.

The hepatic microcirculation: mechanistic contributions and therapeutic targets in liver injury and repair

The complex functions of the liver in biosynthesis, metabolism, clearance, and host defense are tightly dependent on an adequate microcirculation. To guarantee hepatic homeostasis, this requires not only a sufficient nutritive perfusion and oxygen supply, but also a balanced vasomotor control and an appropriate cell-cell communication. Deteriorations of the hepatic homeostasis, as observed in ischemia/reperfusion, cold preservation and transplantation, septic organ failure, and hepatic resection-induced hyperperfusion, are associated with a high morbidity and mortality. During the last two decades, experimental studies have demonstrated that microcirculatory disorders are determinants for organ failure in these disease states. Disorders include 1) a dysregulation of the vasomotor control with a deterioration of the endothelin-nitric oxide balance, an arterial and sinusoidal constriction, and a shutdown of the microcirculation as well as 2) an overwhelming inflammatory response with microvascular leukocyte accumulation, platelet adherence, and Kupffer cell activation. Within the sequelae of events, proinflammatory mediators, such as reactive oxygen species and tumor necrosis factor-alpha, are the key players, causing the microvascular dysfunction and perfusion failure. This review covers the morphological and functional characterization of the hepatic microcirculation, the mechanistic contributions in surgical disease states, and the therapeutic targets to attenuate tissue injury and organ dysfunction. It also indicates future directions to translate the knowledge achieved from experimental studies into clinical practice. By this, the use of the recently introduced techniques to monitor the hepatic microcirculation in humans, such as near-infrared spectroscopy or orthogonal polarized spectral imaging, may allow an early initiation of treatment, which should benefit the final outcome of these critically ill patients.

Prevention of leukocyte activation by the neutrophil elastase inhibitor, sivelestat, in the hepatic microcirculation after ischemia-reperfusion

BACKGROUND

Liver ischemia-reperfusion (I/R) injury is one of the most serious complications of hepatic surgery. However, no effective treatment is yet clinically available. Although neutrophil elastase inhibitor (NEI) has been used clinically in acute lung injury, the effect of NEI on leukocyte dynamics in the liver microcirculation after hepatic I/R remained unclear. The purpose of this study was to use intravital microscopy (IVM) to evaluate the effect of NEI on leukocyte dynamics in the liver microcirculation after hepatic I/R.

METHODS

Hepatic ischemia was induced in male Sprague-Dawley (SD) rats. Sivelestat, a specific NEI, or normal saline (NS) was given as a continuous intravenous infusion before ischemia. The number of adherent leukocytes and the disturbances of sinusoidal perfusion in hepatic microcirculation were observed up to 120 min after reperfusion. Samples of liver tissue and blood were taken for histological examination and measurement of liver enzymes and tissue malondialdehyde (MDA).

RESULTS

Compared with NS, sivelestat significantly decreased the number of adherent leukocytes and prevented perfusion disturbance. In addition, sivelestat obviously improved liver injury as assessed by histological findings and liver enzymes, and prevented the increase of MDA.

CONCLUSIONS

Administration of sivelestat before ischemia effectively suppressed the activation of leukocytes and lipid peroxide, and it consequently prevented hepatic I/R injury.

Physiological and hypoxic O2 tensions rapidly regulate NO production by stimulated macrophages

Nitric oxide (NO) production by inducible NO synthase (iNOS) is dependent on O(2) availability. The duration and degree of hypoxia that limit NO production are poorly defined in cultured cells. To investigate short-term O(2)-mediated regulation of NO production, we used a novel forced convection cell culture system to rapidly (response time of 1.6 s) and accurately (+/-1 Torr) deliver specific O(2) tensions (from <1 to 157 Torr) directly to a monolayer of LPS- and IFNgamma-stimulated RAW 264.7 cells while simultaneously measuring NO production via an electrochemical probe. Decreased O(2) availability rapidly (<or=30 s) and reversibly decreased NO production with an apparent K(m)O(2) of 22 (SD 6) Torr (31 microM) and a V(max) of 4.9 (SD 0.4) nmol min(-1) 10(-6) cells. To explore potential mechanisms of decreased NO production during hypoxia, we investigated O(2)-dependent changes in iNOS protein concentration, iNOS dimerization, and cellular NO consumption. iNOS protein concentration was not affected (P = 0.895). iNOS dimerization appeared to be biphasic [6 Torr (P = 0.008) and 157 Torr (P = 0.258) >36 Torr], but it did not predict NO production. NO consumption was minimal at high O(2) and NO tensions and negligible at low O(2) and NO tensions. These results are consistent with O(2) substrate limitation as a regulatory mechanism during brief hypoxic exposure. The rapid and reversible effects of physiological and pathophysiological O(2) tensions suggest that O(2) tension has the potential to regulate NO production in vivo.

Effects of neutrophil elastase inhibitor on progression of acute lung injury following esophagectomy

The purpose of this study was to evaluate the effect of sivelestat sodium hydrate, a selective inhibitor of neutrophil elastase in the systemic inflammatory response, pulmonary function, and the postoperative clinical course following esophagectomy. Patients with hypoxia associated with surgical stress in the intensive care unit (ICU) immediately after an esophagectomy were eligible for this study. The degree of hypoxia was calculated according to the ratio of arterial oxygen tension (PaO(2)) to the fractional concentration of inspired oxygen (FiO(2))-PaO(2)/FiO(2). Patients with PaO(2)/FiO(2) < 300 mmHg were enrolled in this study. Seven patients were treated with sivelestat, and 10 were not so treated. The degree of hypoxia, the criteria for systemic inflammatory response syndrome (SIRS), and the postoperative clinical course were compared between the two groups. The postoperative decreases in the PaO(2)/FiO(2) ratio were significantly suppressed in the sivelestat group (p < 0.05, by analysis of variance, or ANOVA). Furthermore, 9 of the 10 control group patients developed SIRS on postoperative day 2, whereas only 2 of 7 of the sivelestat group patients developed SIRS (p < 0.05). The postoperative increases in the heart rate were significantly suppressed in the sivelestat group (p < 0.05, ANOVA). The postoperative decreases in the platelet counts were significantly suppressed in the sivelestat group (p < 0.05, ANOVA). The duration of mechanical ventilation and the length of ICU stay for the sivelestat group were shorter than that for the control group. We demonstrated that the postoperative decreases in the PaO(2)/FiO(2) ratio following esophagectomy were significantly suppressed in the sivelestat-treated group. This clinical study showed that a neutrophil elastase inhibitor may thus be a potentially useful drug for treating acute lung injury following esophagectomy.

Protective effect of neutrophil elastase inhibitor (FR136706) in lethal acute liver failure induced by D-galactosamine and lipopolysaccharide in rats

BACKGROUND/AIMS

It has been reported that liver dysfunction with ischemia-reperfusion is improved through selective inhibition of neutrophil elastase (NE) by NE inhibitor. This study was designed to investigate whether NE inhibitor has protective effect in lethal acute liver failure.

MATERIALS AND METHODS

Rats were treated with D-galactosamine plus lipopolysaccharide (GalN/LPS) to induce acute liver failure. NE inhibitor (FR136706) was administered intravenously before GalN/LPS injection.

RESULTS

NE inhibitor increased the survival rate to approximately 80% compared with less than 10% in GalN/LPS-treated rats. NE inhibitor prevented GalN/LPS-induced increase of enzymes and total bilirubin in serum, which are related to liver injury. Histopathological analysis revealed that NE inhibitor decreased the incidence of hepatic apoptosis and neutrophil infiltration in the liver. NE inhibitor inhibited the increased concentration of proinflammatory cytokines (tumor necrosis factor-alpha, interleukin-6 and interferon-gamma), and chemokines (CINC-1 and MIP-2) in serum or liver caused by GalN/LPS, and enhanced anti-inflammatory cytokine, interleukin-10 concentration. NE inhibitor prevented the activation of the transcription factor, nuclear factor-kappa B, induced by GalN/LPS. NE inhibitor also reduced the induction of inducible nitric oxide synthase mRNA and its protein in GalN/LPS-treated liver, and resulted in a decrease in nitric oxide production.

CONCLUSIONS

These results indicate that NE inhibitor, FR136706, inhibits the induction of a variety of inflammatory mediators such as cytokines, chemokines, and nitric oxide, in part through the inhibition of nuclear factor-kappa B activation, resulting in the prevention of fulminant liver failure.

Inhibition of neutrophil elastase attenuates gut mucosal injury evoked by acute alveolar hypoxia in rabbits

The aim of the present study was to examine whether neutrophil and its elastase activity played consequential roles in the progression of gut barrier dysfunction during acute alveolar hypoxia by using a specific neutrophil elastase inhibitor, sivelestat. With our institutional approval, 20 male rabbits (weight, 2.0-2.5 kg) were randomly allocated into two groups: control (n = 11) or sivelestat group (n = 9; bolus, 10 mg/kg, followed by 10 mg/kg per hour). At 4 h of alveolar hypoxia exposure (fraction of inspired oxygen, 0.10) under mechanical ventilation, the white blood cell counts and their function to produce oxygen radicals were measured. Intestinal permeability and myeloperoxidase activity were also assessed concurrently with the examination of histological changes of gut mucosa. The examination of sham animals (n = 4) exposed to normoxia was performed under the same study protocol. The circulating leukocyte counts and the neutrophil chemiluminescence were not different between the groups, whereas the neutrophil elastase activity was significantly increased in the control but not in the sivelestat and sham groups. Permeability, leukocyte accumulation, and myeloperoxidase activity of ileal wall in the control group were significantly elevated, accompanied by apparent destruction of gut mucosa compared with the sivelestat group (P < 0.05). Despite no significant differences in systemic inflammatory responses, the neutrophil elastase activity is a key element in the progression of functional and structural injury of gut mucosa during acute alveolar hypoxia.

Temporary adrenal dysfunction with descending thoracic aortic occlusion

BACKGROUND

We sought to determine whether descending thoracic aortic occlusion (DTAOC) induced ischemia results in adrenal dysfunction.

METHODS

Eight pigs underwent DTAOC for 45 min. Six control pigs underwent a sham procedure. Serum cortisol and adrenocorticotropic hormone (ACTH) were measured at baseline, at the end of DTAOC, 30 and 60 min after restoration of flow, and 24 hours later. Statistical analysis was performed using repeated measures ANOVA and t-test.

RESULTS

In the study group, cortisol levels decreased during DTAOC (p=0.048) and 30 min after flow restoration (p=0.004). In the control group there was no change in serum cortisol levels. In the study group the drop in serum cortisol was associated with an increase in ACTH levels during DTAOC (p=0.040) and 30 minutes after flow restoration (p=0.070). The increase in ACTH was also significant when compared to the controls during DTAOC (p=0.030) and 30 min after blood flow restoration (p=0.040).

CONCLUSIONS

There is a transient period of adrenal dysfunction associated with DTAOC that results in stimulation of the pituitary-adrenal axis.

Neutrophil Elastase Inhibitor, Sivelestat, Attenuates Acute Lung Injury After Cardiopulmonary Bypass in the Rabbit Endotoxemia Model

BACKGROUND

Neutrophil elastase probably contributes to the development of acute lung injury after cardiopulmonary bypass (CPB) in patients with infection or shock. We evaluated whether pretreatment with sivelestat sodium hydrate, a neutrophil elastase inhibitor (EI), can prevent acute lung injury caused by CPB.

METHODS

Rabbits were assigned four groups: CPB for 60 minutes, control CPB group; low-dose lipopolysaccharide (LPS) administration without CPB, LPS group; CPB after lipopolysaccharide administration, LPS+CPB group; or preparation with continuous infusion of sivelestat and CPBs after lipopolysaccharide administration, EI group. Blood samples to determine blood gas concentration, plasma elastase activity, and plasma interleukin-8 levels were obtained. Histopathologic examinations of the lung were performed.

RESULTS

The decreased arterial oxygen pressure at the end of CPB was observed in the LPS+CPB group only, but was suppressed in the EI group (p < 0.01). Elastase activity was markedly elevated at 120 minutes after CPB, and interleukin-8 levels were markedly elevated at 180 minutes in the LPS+CPB group but were much lower (p < 0.05) in the EI group. Histopathology demonstrated accumulation of polymorphonuclear neutrophils in bronchoalveolar areas in the LPS+CPB group (p < 0.01). Pulmonary myeloperoxidase activity was significantly lower in the LPS+CPB group than in the other groups (p < 0.01). These changes were minimal in the EI group.

CONCLUSIONS

The combination of low dose LPS+60 minutes of CPB, but neither intervention alone, produced evidence of acute lung injury in a rabbit model. This did not occur when the animals were pretreated with sivelestat.

The full-length cDNA of anticoagulant protein infestin revealed a novel releasable Kazal domain, a neutrophil elastase inhibitor lacking anticoagulant activity

Infestins are Kazal-type serine proteinase inhibitors found in the midgut of the Chagas' disease vector, Triatoma infestans. In previous studies, we characterized two double-headed infestins with potent anticoagulant activity; infestin 1-2, which inhibits thrombin and infestin 3-4, a factor XIIa inhibitor. In the present work, we have cloned the full-length cDNA of infestins' precursor. The translated cDNA predicted a polypeptide containing a signal peptide and seven Kazal-type domains, four domains from infestin 1-2 and infestin 3-4, and three new domains. Northern blot analysis confirmed that infestins are synthesized in a single transcript (approximately 1,800 bp) in the insect midgut, but not in salivary glands. Based on the cDNA sequence, the three new Kazal domains were named infestin 1R, 2R and 3R. Infestin 2R-3R has 77% amino acid sequence identity to infestin 1-2 and the same basic amino acid residue at P1 position in the inhibitory reactive site suggesting that these two proteins have a similar inhibitory specificity. In contrast, infestin 1R has two different characteristics when compared to the other infestins: i) a hydrophobic amino acid residue at P1 position in the inhibitory reactive site and ii) a prediction to be processed as a single Kazal domain. These two characteristics were experimentally demonstrated by the purification of native infestin 1R from T. infestans midgut. Native infestin 1R was shown to be processed as a single Kazal domain by mass spectrometry and it was able to inhibit neutrophil elastase, subtilisin A and chymotrypsin. To further characterize infestin 1R inhibitory activity, it was expressed as a recombinant protein in bacteria. Recombinant infestin 1R inhibited neutrophil elastase with the same K(i) of the native inhibitor. Moreover, it inhibited subtilisin A, chymotrypsin and proteinase K but did inhibit neither thrombin nor coagulation assays. In conclusion, unlike the other described infestins, infestin 1R did not present anticoagulant activity and is processed as a single Kazal domain with inhibitory specificity towards proteases that hydrolyze peptide bonds after hydrophobic amino acid residues.

Effects of intrarenal administration of the cox-2 inhibitor parecoxib during porcine suprarenal aortic cross-clamping

The aim of this study was to investigate the effects of intrarenal administration of the cyclooxygenase-2 inhibitor parecoxib during suprarenal aortic cross-clamping. In a prospective, controlled, blinded, randomized manner, 16 anesthetized and mechanically ventilated pigs were instrumented to measure systemic and right kidney hemodynamics, oxygen exchange, and metabolism. During 45 min of suprarenal aortic cross-clamping, animals received 40 mg of parecoxib (n = 8) or vehicle (n = 8) infused continuously into the right renal artery. Hemodynamic and metabolic data, right kidney venous blood, as well as urine samples were obtained before clamping, as well as before and 75 and 195 min after declamping. Clamping transiently increased mean arterial pressure in both groups. Systemic and renal blood flow did not differ between the pre- and postclamping measurements or between groups. Parecoxib attenuated the otherwise significant fall in right kidney creatinine clearance (controls: from 45 [7;111] to 17 [9;22] mL/min; parecoxib: from 39 [3;59] to 27 [11;45] mL/min, P = 0.039 and P = 0.297, respectively versus before clamping, P = 0.021 versus controls at 195 min) and prevented the impairment of renal lactate balance observed in the control group (controls: from 0.5 [-0.8;3.5] to 0.2 [-0.2;0.6] mumol/kg/min; parecoxib: from 0.6 [-1.0;2.0] to 0.4 [-1.2;0.6] mumol/kg/min, P = 0.038 and P = 0.285, respectively, versus before clamping). In conclusion, intrarenal parecoxib infusion beneficially influenced kidney function in this clinically relevant model of suprarenal aortic cross-clamping.

Tissue-specific expression of estrogen receptors and their role in the regulation of neutrophil infiltration in various organs following trauma-hemorrhage

Although 17beta-estradiol (E2) administration after trauma-hemorrhage (T-H) reduces tissue neutrophil sequestration in male rodents, it remains unknown which of the estrogen receptor (ER) subtypes mediates this effect and whether the same ER subtype is involved in all the tissues. We hypothesized that the salutary effects of E2 on attenuation of neutrophil accumulation following T-H are tissue and receptor subtype-specific. Male Sprague-Dawley rats underwent sham operation or T-H (mean blood pressure, 40 mmHg for 90 min and then resuscitation). E2 (50 microg/kg), ER-alpha agonist propyl pyrazole triol (PPT; 5 microg/kg), ER-beta agonist diarylpropiolnitrile (DPN; 5 microg/kg), or vehicle (10% dimethyl sulfoxide) was administered subcutaneously during resuscitation. Twenty-four hours thereafter, tissue myeloperoxidase (MPO) activity (a marker of neutrophil sequestration), cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-3, and intercellular adhesion molecule (ICAM)-1 levels in the liver, intestine, and lung were measured (n = 6 rats/group). ER-alpha and ER-beta mRNA levels in sham-operated rats were also determined. T-H increased MPO activity, CINC-1, CINC-3, and ICAM-1 levels in the liver, intestine, and lung. These parameters were improved significantly in rats receiving E2 after T-H. Administration of the ER-alpha agonist PPT but not the ER-beta agonist DPN improved the measured parameters in the liver. In contrast, DPN but not PPT significantly improved these parameters in the lung. In the intestine, ER subtype specificity was not observed. ER-alpha mRNA expression was highest in the liver, whereas ER-beta mRNA expression was greatest in the lung. Thus, the salutary effects of E2 administration on tissue neutrophil sequestration following T-H are receptor subtype and tissue-specific.