Inhibition of enteral enzymes by enteroclysis with nafamostat mesilate reduces neutrophil activation and transfusion requirements after hemorrhagic shock

BACKGROUND: The gut origin of the inflammatory response in trauma patients has been difficult to define. "In vivo" generation of neutrophil-activating factors by gut proteases may be a cause of multiorgan failure after hemorrhagic shock, and can be prevented with the serine protease inhibitor nafamostat mesilate (Futhan). The objective of this study was to determine the effect of nafamostat mesilate given by enteroclysis on enteric serine protease activity, neutrophil activation, and transfusion requirements during hemorrhagic shock. METHODS: Sixteen pigs weighing 21 to 26 kg were divided into control and treatment groups. A laparotomy was performed under anesthesia, and catheters were placed in the duodenum, midjejunum, and terminal ileum. Pigs were bled 30 mL/kg over 30 minutes and maintained at a mean arterial pressure of 30 mm Hg for 60 minutes. Shed blood was then used to maintain a mean arterial pressure of 45 mm Hg for another 3 hours. Treated animals received 100 mL/kg of 0.37 mmol/L nafamostat mesilate in GoLYTELY through the duodenal catheter at 1 L/h. Control animals received GoLYTELY only. Samples of enteral content and blood were taken at baseline, after shock, and at 30-minute intervals during resuscitation. Animals were killed after 3 hours of resuscitation. Enteral trypsin-like activity at the three gut sites was measured by spectrophotometry. Activation of naive human neutrophils by pig plasma was measured by the percentage of cells having pseudopods larger than 1 microm on microscopy. Lung, liver, and small bowel were analyzed by histology and myeloperoxidase assay. RESULTS: Both control and nafamostat mesilate-treated groups had significant reductions in protein and protease levels in the duodenum during enteroclysis; however, only nafamostat mesilate-treated animals had persistent suppression of protease activity throughout the experiment. Nafamostat mesilate-treated animals had a lower transfusion requirement of shed blood, 18.1 +/- 4.5 mL/kg versus 30 +/- 0.43 mL/kg (p = 0.002). Nafamostat mesilate-treated animals had significantly less neutrophil activation than controls at 150 minutes after resuscitation (33.7 +/- 6.48% vs. 42.4 +/- 4.57%,p = 0.01) and 180 minutes after resuscitation (31.1 +/- 3.31% vs. 46.9 +/- 4.53%, p = 0.0002). Lung myeloperoxidase activity was lower in nafamostat mesilate-treated animals (0.31 +/- 0.14) than in control animals (0.16 +/- 0.04, p = 0.04). Histology of liver and small intestine showed less injury in nafamostat mesilate-treated animals. CONCLUSION: Nafamostat mesilate given by means of enteroclysis with GoLYTELY significantly reduces enteral protease levels, leukocyte activation, and transfusion requirements during resuscitation from hemorrhagic shock. This strategy may have clinical promise.     

Inhibition of CD18-dependent leukocyte adherence by mAb 6.5 E does not prevent ischemia-reperfusion injury as seen in grafted kidneys

The present study was designed to determine whether -2 integrin-mediated leukocyte adherence to the endothelium is involved in renal ischemia-reperfusion damage and to evaluate the therapeutic intervention potency of monoclonal antibody (mAb) 6.5 E, directed against the leukocyte CD18 adhesion molecule. To answer these questions, we used a clinically relevant canine model for the autotransplantation of kidneys that had been subjected to 30 min of normothermic ischemia, followed by 24 h of cold storage preservation. Intravital fluorescence microscopy of capsular microvessels showed that substantial leukocyte adherence occurred after renal ischemia and reperfusion. Leukocyte adherence was observed in both arterioles and venules, but predominantly in the latter. Reperfusion of the graft resulted in a statistically significant reduction of the venular red blood cell velocity (RBCV). Moreover, the venular diameter increased. No significant changes in the arteriolar RBCV or in the arteriolar diameter were observed. Administration of mAb 6.5 E, 1 h before reperfusion, inhibited leukocyte adherence to the renal microvascular endothelium, resulting in an improved venular flow 2 h after reperfusion. However, we observed no beneficial effect of mAb 6.5 E pretreatment on posttransplant graft function and survival. We conclude that leukocyte adherence does not play a critical role in the development of renal injury following reperfusion of kidneys that have been subjected to prolonged warm and cold ischemia.     

Hypertonic saline resuscitation of hemorrhagic shock diminishes neutrophil rolling and adherence to endothelium and reduces in vivo vascular leakage

OBJECTIVE: To evaluate the in vivo effects of hypertonic saline (HTS) resuscitation on the interactions of endothelial cells (ECs) and polymorphonuclear neutrophils (PMNs) and vascular permeability after hemorrhagic shock. SUMMARY BACKGROUND DATA: The PMN has been implicated in the pathogenesis of EC damage and organ injury following hemorrhagic shock. Compared to Ringer's lactate (RL), HTS resuscitation diminishes PMN and EC adhesion molecule expression and organ sequestration of PMNs. METHODS: In a murine model of hemorrhagic shock (50 mmHg for 45 minutes followed by resuscitation) using intravital microscopy on cremaster muscle, the authors studied PMN-EC interactions and vascular leakage (epifluorescence after 50 mg/kg fluorescent albumin) in three resuscitation groups: HTS (shed blood + 4 cc/kg 7.5% HTS, n = 12), RL (shed blood + RL [2x shed blood volume], n = 12), and sham (no hemorrhage or resuscitation, n = 9). EC ICAM-1 expression was evaluated by immunohistochemistry. Data, presented as mean +/- SEM, were evaluated by analysis of variance with Bonferroni correction. RESULTS: There were no differences between groups in flow mechanics. Compared to RL, HTS animals (t = 90 minutes) displayed diminished PMN rolling and PMN adhesion to EC at time intervals beyond t = 0. There were no differences between the sham and HTS groups. Vascular leakage was 45% lower in HTS than in RL-resuscitated animals. Cremaster EC ICAM-1 expression was similar in the two groups. CONCLUSIONS: Using HTS instead of RL to resuscitate hemorrhagic shock diminishes vascular permeability in vivo by altering PMN-EC interactions. HTS could serve as a novel means of immunomodulation in hemorrhagic shock victims, potentially reducing PMN-mediated tissue injury.     

Glutathione deficiency increases organ dysfunction after hemorrhagic shock.

BACKGROUND. Reactive oxygen metabolites contribute to tissue destruction in a wide variety of diseases. Glutathione, a potent endogenous antioxidant, neutralizes the destructive potential of free radicals, but this tripeptide may be depleted during illness. We hypothesized that glutathione deficiency would amplify organ dysfunction after shock in rats. METHODS. Rats received either diethyl maleate to deplete tissue glutathione or a control solution intraperitoneally. The animals were subsequently bled to and maintained at a mean arterial pressure of 40 mm Hg for 30 minutes and then fully resuscitated. Sham animals underwent blood pressure monitoring only. Tissue glutathione, liver and renal function tests, organ bacterial content, and mortality rates were determined 4 and 24 hours after shock. RESULTS. Normal rats subjected to shock and sham animals had similar laboratory chemistry results, organ culture results, and mortality rates. However, glutathione-depleted animals subjected to shock had elevated liver and renal function tests, increased organ bacteria, and a dramatic increase in mortality rates compared with control shock and sham animals. CONCLUSIONS. We conclude that glutathione deficiency predisposes animals to organ failure and death after an otherwise nonlethal period of hypotension. Because glutathione deficiency is associated with severe injury and sepsis, treatment strategies that maintain glutathione stores may decrease the incidence of multisystem organ failure.     

Pancreatic duct ligation reduces lung injury following trauma and hemorrhagic shock

OBJECTIVE: To determine whether pancreatic digestive enzymes released into the ischemic gut during an episode of T/HS are involved in the generation of distant organ injury. This hypothesis was tested by examining the effect of PDL on T/HS-induced intestinal injury, lung injury, and RBC deformability. SUMMARY BACKGROUND DATA: The effect of pancreatic duct ligation (PDL) on distant organ injury following trauma/hemorrhagic shock (T/HS) was examined. PDL before T/HS decreases lung and red blood cell (RBC) injury and exerts a limited protective effect on the gut. Pancreatic proteases in the ischemic gut appear to be involved in gut-induced lung and RBC injury. Based on recent work, it appears that proinflammatory and/or toxic factors, which are generated by the ischemic intestine, play an important role in the pathogenesis of multiple organ failure. The process by which these toxic factors are generated remains unknown. Previous experimental work has clearly documented that intraluminal inhibition of pancreatic proteases decreases the degree of T/HS-induced lung injury and neutrophil activation. One possible explanation for this observation is that the toxic factors present in intestinal lymph are byproducts of interactions between pancreatic proteases and the ischemic gut. METHODS: Male Sprague-Dawley rats were subjected to a laparotomy (trauma) and 90 minutes of sham (T/SS) or T/HS with or without PDL. At 3 and 24 hours following resuscitation, animals were killed and samples of gut, lung, and blood were collected for analysis. Lung permeability, pulmonary myeloperoxidase levels, and bronchoalveolar fluid protein content were used to quantitate lung injury. Intestinal injury was determined by histologic analysis of terminal ileum (% villi injured). To assess RBC injury, RBC deformability was measured, as the RBC elongation index (RBC-EI), using a LORCA device. RESULTS: At 3 and 24 hours following resuscitation, PDL prevented shock-induced increases in lung permeability to both Evans blue dye and protein in addition to preventing an increase in pulmonary myeloperoxidase levels. T/HS-induced impairments in RBC deformability were significantly reduced at both time points in the PDL + T/HS group, but deformability did not return to T/SS levels. PDL did reduce the magnitude of ileal injury at 3 hours after T/HS, but the protective effect was lost at 24 hours after T/HS. CONCLUSIONS: PDL prior to T/HS decreases lung injury and improves RBC deformability but exerts a limited protective effect on the gut. Thus, the presence of pancreatic digestive enzymes in the ischemic gut appears to be involved in gut-induced lung and RBC injury.     

Role of CD18-dependent neutrophil recruitment in skin and intestinal wound healing.

CD11/CD18 is an important adhesion molecule mediating recruitment of leukocytes, which, in turn, may cause postoperative injury in the skin and gastrointestinal tract. The objective of the present study was to investigate the effects of inhibiting the function of CD18 on surgery-induced dermal and intestinal infiltration of neutrophils and on the healing of surgical skin flaps and colonic anastomosis. A flap in the dorsal skin or an end-to-end colonic anastomosis were created in Sprague-Dawley rats. Skin necrosis and anastomotic breaking strength were analyzed 6 and 3 days after surgery, respectively. Tissue myeloperoxidase (MPO) was used as a marker of neutrophil recruitment. Administration of a monoclonal antibody directed against rat CD18 (WT.3, 2 mg/kg) significantly decreased dermal and anastomotic MPO activity by more than 80%. Passive immunization against CD18 significantly improved flap survival, i.e. the survival was 80% in the anti-CD18 antibody group as compared to 38% in the control group. In contrast, this passive immunization against CD18 had no effect on the reconstitution of the integrity of the colonic anastomosis, i.e. the anastomotic breaking strength was 1.3 +/- 0.1 and 1.3 +/- 0.3 N in the control and anti-CD18 antibody group, respectively. These findings suggest that specific inhibition of CD18 function and reduced neutrophil recruitment may improve the survival of experimental skin flaps and, thus, may represent a potential target for therapeutic intervention. In contrast, we also found that blocking CD18-dependent neutrophil infiltration in the intestine had no effect on breaking strength of colonic anastomosis. Thus, neutrophils may influence the wound-healing process differently in specific organs and this needs to be considered when applying an anti-inflammatory treatment regime in order to improve tissue healing.     

创伤/失血性休克后期肺损伤的性别差异

背景与目的 我们以前的研究发现:创伤/失血性休克(T/HS)复苏后早期(3小时)肺损伤明显.雌性动物较雄性动物耐受性强.但是,T/HS后期肺损伤是否依然存在.是否具有性别差异目前仍然未知,本研究观察雌、雄动物T/HS后期肺损伤的差异.方法 雌、雄性SD大鼠剖腹(创伤)后经颈动脉放血致T/HS或假休克(T/SS),90分钟后休克大鼠用乳酸林格氏液(RL)复苏;复苏后5天评估肺损伤的情况.结果 T/HS后大鼠的肺通透性、肺髓过氧化物酶(MPO)水平以及支气管肺泡灌注液(BALF)蛋白浓度与血浆蛋白浓度的比值增加,雌性大鼠的上述变化与雄性大鼠相比更加显著.结论 创伤,失血性休克5天后仍然存在肺损伤.而且有显著的性别差异,雌性大鼠肺损伤较雄性大鼠重.     

Detection of organ ischemia during hemorrhagic shock

BACKGROUND: In a porcine hemorrhagic shock model we aimed to determine: (a) whether blood flow to the intestine and kidney was more reduced than cardiac output; (b) whether parameters of anaerobic metabolism correlated with regional blood flow; and (c) whether metabolic parameters in intestine, kidney and skeletal muscles detected a compromised metabolic state at an earlier stage than did systemic parameters. METHODS: In an animal research laboratory at a university hospital six domestic pigs were subjected to volume-controlled hemorrhage. Every 30 min samples of blood were withdrawn. Systemic and regional hemodynamic parameters and tissue levels of PCO2 were monitored. Whole body and organ-specific oxygen consumption (VO2) and veno-arterial (VA) differences of lactate, glucose, potassium (K+), PCO2, H+ and base excess (BE) were calculated every 30 min. RESULTS: With progressive hemorrhage, intestinal blood flow decreased to the same extent as cardiac output, whereas the reduction in renal blood flow was more pronounced. We found a concomitant reduction in VO2 (onset of supply dependent metabolism) in intestine, kidney and skeletal muscles. In muscular tissue PCO2 increased to levels three times higher than baseline, while renal and intestinal PCO2 increased eightfold. Supply dependency was associated with a concomitant increase in VA CO2 and VA H+. Also, VA lactate increased, mostly in intestine and least in skeletal muscle. Intestinal and renal VA K+ increased, while muscular VA K+ decreased. Arterial lactate and H+ increased considerably, whereas arterial BE decreased. CONCLUSION: With progressive hemorrhage, renal blood flow, but not intestinal and skeletal muscle blood flow, was reduced more than cardiac output. Supply dependent oxygen metabolism (VO2) and organ acidosis occurred simultaneously in the three organs, despite differences in blood flow reductions. Organ ischemia coincided with a pronounced change in arterial lactate and systemic acid base parameters.     

A novel method of peritoneal resuscitation improves organ perfusion after hemorrhagic shock

BACKGROUND: After resuscitation from hemorrhagic shock, intestinal microvessels constrict leading to impairment of blood flow. This occurs despite restoration and maintenance of central hemodynamics. Our recent studies have demonstrated that topical and continuous exposure of the gut microvasculature to a clinical solution (Delflex; Fresenius Medical Care), as a technique of direct peritoneal resuscitation (DPR), reverses the postresuscitation vasoconstriction and hypoperfusion to a sustained dilation and hyperperfusion. We hypothesize that initiation of DPR simultaneously with resuscitation from hemorrhagic shock enhance organ blood flow to all tissues surrounding the peritoneal cavity as well as distant organs. METHODS: Male Sprague-Dawley rats were anesthetized, intubated and cannulated for monitoring of hemodynamics and for withdrawal of blood. Rats were hemorrhaged to 50% of mean blood pressure for 60 minutes prior to resuscitation with shed blood plus 2 volumes of saline. Animals were randomized for intraperitoneal therapy with 30 mL saline (group 1, n = 9), or Delflex (group 2, n = 9). Whole organ blood flow was measured by colorimetric microsphere technique with phantom organ at baseline, after completion of resuscitation, and at 120 minutes postresuscitation. Replenishment of the dwelling intraperitoneal saline or Delflex was performed in (group 3, n = 8), and (group 4, n = 8), respectively at 90 minutes postresuscitation, and a single whole organ blood flow was performed at 120 minutes postresuscitation. RESULTS: Direct peritoneal resuscitation caused a significant increase in blood flow to the jejunum (35%), ileum (33%), spleen (48%), and pancreas (57%), whereas a marked increase in blood flow was detected in the lung (111%), psoas major muscle (115%), and diaphragm (132%), as compared with the saline treated animals in group 1. At 120 minutes postresuscitation, organ blood flow returned to the prehemorrhagic shock baseline level in all organs irrespective of peritoneal therapy. Replenishment of the intraperitoneal solution in group 3 and 4, enhanced blood flow to the liver, kidneys, and diaphragm. CONCLUSIONS: Direct peritoneal resuscitation enhanced blood flow to organs incited in the pathogenesis of multiple organ failure that follows hemorrhagic shock.     

Hypothermia reduces microvascular permeability and reactive oxygen species expression after hemorrhagic shock

BACKGROUND: Hypothermia is a frequent manifestation after trauma-induced hemorrhagic shock. Clinical studies have suggested that hypothermia is an independent risk variable predisposing patients to an increase in morbidity. Thus, most of the current goal-directed resuscitation protocols are aimed at the establishment of euthermia. However, recent data suggest that hypothermia may provide protection by attenuating the inflammatory response after hemorrhagic shock. The purpose of this study was twofold: to examine the effects of mild to moderate hypothermia on barrier function after hemorrhagic shock, and to determine the role of reactive oxygen species (ROS) in this process. METHODS: After a control period, blood was withdrawn to reduce the mean arterial pressure to 40 mm Hg for 1 hour in urethane-anesthetized rats. Mesenteric postcapillary venules in a transilluminated segment of small intestine were examined to quantitate changes in permeability and ROS expression. Sprague-Dawley rats received an intravenous injection of fluorescein isothiocyanate (FITC)-albumin during the control period. The fluorescent light intensity emitted from the FITC-albumin was recorded with digital microscopy within the lumen of the microvasculature and compared with the intensity of light in the extravascular space. The images were downloaded to a computerized image analysis program that quantitates changes in light intensity. This change in light intensity represents albumin-FITC extravasation. RESULTS: Our results demonstrated a marked increase in albumin leakage after hemorrhagic shock that was significantly attenuated with mild (34 degrees C) and moderate (30 degrees C) hypothermia. In addition, hypothermia attenuated ROS expression after hemorrhagic shock. CONCLUSION: These data suggest that hypothermia may protect barrier integrity after hemorrhagic shock by inhibition of oxygen radical expression.     

Delayed-onset pulmonary insufficiency in primates resuscitated from hemorrhagic shock.

Forty-one unanesthetized cynomolgus monkeys were subjected to 2 hours of hemorrhagic hypotension at various mean arterial pressures (MAP) between 40 and 60 mm Hg. Resuscitation and maintenance of MAP were provided by lactated Ringer's solution and homologous blood. Thirty-eight per cent (57% of those surviving greater than 24 hours) developed a delayed-onset (18 to 24 hours) pulmonary insufficiency in spite of good urinary output, and which did not respond to furosemide. The group in which this caused death (24%) showed significantly decreased PaO2, PaCO2, dynamic compliance, and FECO2, and increased minute volume, Qs/Qt, pulmonary artery pressure, and VD/VT before death. Their lungs were heavier, with abnormal pressure/volume curves and increased minimum surface tension. During the entire post-resuscitation phase, this group remained in a high-output, low-resistance hemodynamic state in contract to survivors and those dying of shock. The implications regarding current practices of monitoring and resuscitating patients with traumatic shock are discussed.     

Complement activation mediates intestinal injury after resuscitation from hemorrhagic shock

BACKGROUND: Endothelial cell injury after hemorrhage and resuscitation (HEM/RES) might contribute to intestinal hypoperfusion and mucosal ischemia. Our recent work suggests that the injury might be the result of complement activation. We hypothesized that HEM/RES causes complement-mediated endothelial cell dysfunction in the small intestine. METHODS: Male Sprague-Dawley rats (195-230 g) were anesthetized and HEM to 50% of baseline mean arterial pressure for 60 minutes. Just before RES, animals received either soluble complement receptor-1 (sCR1, 15 mg/kg) to inhibit complement activation or saline vehicle. Resuscitation was with shed blood and an equal volume of saline. Two hours after RES, the small bowel was harvested to evaluate intestinal nitric oxide synthase activity (NOS), neutrophil influx, histology, and oxidant injury. RESULTS: HEM/RES induced tissue injury, increased neutrophil influx, and reduced NOS activity by 50% (vs. SHAM), all of which were completely prevented by sCR1 administration. There were no observed differences in oxidant injury between the groups. CONCLUSION: Histologic tissue injury, increased neutrophil influx, and impaired NOS activity after HEM/RES were all prevented by complement inhibition. Direct oxidant injury did not seem to be a major contributor to these alterations. Complement inhibition after HEM might ameliorate reperfusion injury in the small intestine by protecting the endothelial cell, reducing neutrophil influx and preserving NOS function.     

Administration of progesterone after trauma and hemorrhagic shock prevents hepatocellular injury

HYPOTHESIS: Administration of a single dose of progesterone following trauma and hemorrhage in progesterone-deficient rats would ameliorate the inflammatory response and hepatocellular damage. SETTING: A university laboratory. INTERVENTIONS: Ovariectomized female Sprague-Dawley rats (250-350 g; Charles River Laboratories, Wilmington, Mass) underwent a 5-cm midline laparotomy (ie, induction of soft tissue trauma), were bled to a mean arterial blood pressure of 35 mm Hg for about 90 minutes, and then were resuscitated using Ringer lactate solution. Progesterone (25 mg/kg of body weight) or vehicle was administered subcutaneously at the end of resuscitation. In additional animals, Kupffer cells were isolated following trauma, hemorrhage, and resuscitation and treated in vitro with progesterone, lipopolysaccharide, or both. MAIN OUTCOME MEASURES: Six hours following resuscitation, plasma tumor necrosis factor alpha (TNF-alpha) and interleukin 6 (IL-6) levels and liver myeloperoxidase activity were determined. Hepatocellular function (maximum velocity of indocyanine green clearance [Vmax] and the efficiency of the active transport or Michaelis-Menten constant [Km]) and plasma levels of transaminases were measured 20 hours after resuscitation. Kupffer cell IL-6 and TNF-alpha production were assessed. RESULTS: Plasma levels of TNF-alpha, IL-6, aspartate aminotransferase, and alanine aminotransferase, as well as hepatic myeloperoxidase activity were increased, whereas indocyanine green clearance was depressed in vehicle-treated rats following trauma-hemorrhage. Animals treated with progesterone showed significantly reduced levels of the TNF-alpha, IL-6, and transaminases as well as reduced myeloperoxidase activity in the liver. Progesterone-treated animals showed increased Vmax and Kmax values for indocyanine green. In vitro treatment of Kupffer cells with progesterone decreased TNF-alpha production but did not affect the production of IL-6. CONCLUSION: Progesterone administration following trauma-hemorrhage ameliorates the proinflammatory response and, subsequently, the hepatocellular injury via direct action on immunocompetent cells.     

Acute lung injury after hemorrhagic shock is dependent on gut injury and sex

Recent studies have established gut-derived lymph rather than portal blood as the major source of toxic mediators after hemorrhagic shock that causes distant organ injury. Similarly, emerging data have identified sex as a major modifier of the response to injury and illness. Thus we tested the hypothesis that female rats would be more resistant to shock-induced lung injury than male rats because females are more resistant to shock-induced gut injury and produce mesenteric lymph that is less toxic to endothelial cells. Male and female rats were subjected to sham or hemorrhagic shock and lung permeability was quantitated by Evans blue dye and protein extravasation into the alveolar space. Next, mesenteric lymph collected from shocked and sham-shocked rats of both sexes was incubated with human umbilical vein endothelial cells (HUVECs) and assayed for toxicity. Trypan blue dye exclusion and the release of lactate dehydrogenase assessed HUVEC viability and injury respectively. Lastly, sections of the terminal ileum were histologically examined for evidence of shock-induced mucosal injury. Male rats but not female rats subjected to hemorrhagic shock had evidence of increased lung permeability and produced mesenteric lymph that was cytotoxic to HUVECs. Shock caused gut injury in the male rats whereas histological evidence of gut injury was not observed in the female rats. Hemorrhagic shock-induced lung injury depends on gut injury and mesenteric lymph appears to be the route by which gut-derived toxic factors exit the gut to cause lung injury. The resistance of female rats to shock-induced lung injury appears to be secondary to their resistance to shock-induced gut injury.     

Prehospital HBOC-201 after traumatic brain injury and hemorrhagic shock in swine

BACKGROUND: Data are limited on the actions of hemoglobin based oxygen carriers (HBOCs) after traumatic brain injury (TBI). This study evaluates neurotoxicity, vasoactivity, cardiac toxicity, and inflammatory activity of HBOC-201 (Biopure, Cambridge, Mass.) resuscitation in a TBI model. METHODS: Swine received TBI and hemorrhage. After 30 minutes, resuscitation was initiated with 10 mL/kg normal saline (NS), followed by either HBOC-201 (6 mL/kg, n = 10) or NS control (n = 10). Supplemental NS was administered to both groups to maintain mean arterial pressure (MAP) >60 mm Hg until 60 minutes, and to maintain cerebral perfusion pressure (CPP) >70 mm Hg from 60 to 300 minutes. The control group received mannitol (1 g/kg) and blood (10 mL/kg) at 90 minutes and half (n = 5) received CPP directed phenylephrine (PE) therapy after 120 minutes. Serum cytokines were measured with ELISA and coagulation was evaluated with thromboelastography. Brains were harvested for neuropathology. RESULTS: With HBOC administration, MAP, CPP, and brain tissue PO2 were restored within 30 minutes and maintained until 300 minutes. Clot strength and fibrin formation were maintained and 9/10 successfully extubated. In contrast, with control, MAP and brain tissue PO2 did not correct until 120 minutes, after mannitol, transfusion and 40% more crystalloid. Furthermore, without PE, CPP did not reach target and 0/5 could be extubated. Lactate, heart rate, cardiac output, mixed venous oxygenation, muscle oxygenation, serum cytokines, and histology did not differ between groups. CONCLUSIONS: After TBI, a single HBOC-201 bolus with minimal supplements provided rapid resuscitation, while maintaining CPP and improving brain oxygenation, without causing cardiac dysfunction, coagulopathy, cytokine release, or brain structural changes.     

Mesenteric lymph duct ligation against renal injury in rats after hemorrhagic shock

Background: The kidney is a common target in multiple organ dysfunction syndrome (MODS). The aim of this study is to determine the role of intestinal lymphatic pathway on renal injury in hemorrhagic shock rats. Methods: Wistar rats were divided into sham, shock, and ligation groups. The hemorrhagic shock model was induced in the shock and ligation groups. After resuscitation, the mesenteric lymph ducts were ligated in the ligation group. Blood from the carotid artery was taken to determine renal functional indices. The kidneys were used to observe histomorphological changes at 6 h after resuscitation. In addition, kidney homogenate was used to determine malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor alpha (TNFα), interleukin-6 (IL-6), and myeloperoxidase (MPO) levels at 90 min after shock and 0, 1, 3, 6, 12, and 24 h after resuscitation. And the survival rate of 24 h was recorded. Results: The survival rate in shock group was obviously lower than sham and ligation groups. The urea and creatinine contents in the serum of shock and ligation groups were significantly higher than the sham group; the indices in the ligation group were significantly lower than the shock group. Histological studies showed various degrees of renal injury in the shock and ligation groups with a lesser severity in the ligation group. MDA, TNFα, IL-6, and MPO in renal homogenate of the shock group were raised, and the activity of SOD was lower in comparison to the sham group. Further, MDA, TNFα, IL-6, and MPO in renal homogenate of the ligation group at 6, 12, and 24 h were lower, and the SOD activity was higher than that of the shock group at the same time points. Conclusion: The mesenteric lymph duct ligation could be used to attenuate renal injury in shock rats. Its mechanism might be related to reducing the polymorph nuclear (PMN) and decreasing inflammatory mediator and free radical.     

Inhibition of matrix metalloproteinases reduces local and distant organ injury following experimental acute pancreatitis

BACKGROUND: Pulmonary complications from pancreatitis involve parenchymal destruction via proteolytic enzymes. Matrix metalloproteinases (MMPs) may play an important role in pulmonary injury following acute severe pancreatitis. We hypothesized that local and distant organ injury would be decreased by the presence of an MMP inhibitor (Batimistat; BB-94) following severe acute pancreatitis (AP). METHODS: Eighteen male rats were randomized into two groups: BB-94 (AP + 40 mg/kg/24 h BB-94 ip x three doses) or control (AP + 20 ml/kg/24 h normal saline ip x three doses). Necrotizing AP was induced by retrograde infusion of 5% sodium taurocholate (1.5 ml/kg) into the pancreatic duct. Twenty additional animals were randomized into BB-94 and control groups for the survival study. Serum was evaluated for amylase and MMP activity. Pancreatic sections were graded for edema, necrosis, neutrophil infiltrate, and hemorrhage. Myloperoxidase (MPO) activity was used to determine PMN infiltration in the lung. Evan's Blue dye extravasation was used to quantify vascular permeability. RESULTS: Animals in the BB-94 group had decreased amylase levels (1086.0 +/- 61.7 U/L vs 2232.7 +/- 309.9 U/L; P < 0.05), decreased cellular infiltrate (1.4 +/- 0.2 vs 2.3 +/- 0.2; P < 0.02), and decreased necrosis (4.1 +/- 0.3 vs 6.1 +/- 0.4; P < 0.005) compared to the control group. Lung tissue following pancreatitis in the BB-94 group demonstrated decreased MPO activity (41.5 +/- 2.4 units vs 57.3 +/- 2.9 units; P < 0.05) and decreased vascular permeability (18.3 +/- 2.8 mg/100 g vs 30.1 +/- 4.6 mg/100 g; P < 0.05). Animals treated with BB-94 had 100% survival compared to 50% survival in control at 72 h. CONCLUSIONS: Pancreatitis results in increased local and distant MMP activity. Pulmonary and pancreatic injury following AP can be abrogated by treatment with an MMP inhibitor (Batimistat; BB-94) which may result in decreased morbidity and mortality.