Gabexate mesilate, a synthetic protease inhibitor, attenuates endotoxin-induced pulmonary vascular injury by inhibiting tumor necrosis factor production by monocytes

Effects of Gabexate Mesylate on the Gut Microbiota and Metabolomics in Rats with Sepsis

Background

Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection. However, there is still no single drug that could reduce septic mortality. Previous studies have reported gabexate mesylate (GM) significantly reduced serum inflammatory factors, alleviated sepsis-induced lung injury and improved clinical outcomes. This study aimed to combine with microbiome sequencing and metabolomics analysis to explore the effects of GM administration in septic rats.

Methods

Sixty SD rats were randomly divided into the sham control (SC), cecal ligation and puncture (CLP), and GM injection (GM) groups. The mortality was measured and colonic feces were collected to examine the gut microbiota and metabolism 24 h after the procedure. The lung tissues were collected for hematoxylin-eosin staining.

Results

We observed the relative abundance of Pygmaiobacter, which contributed to short-chain fatty acids (SCFAs) promotion, Lactobacillus and Erysipelotrichaceae UCG-003 increased in the GM-treated rats, while Escherichia-Shigella and Akkermansia decreased compared to the sepsis-induced lung injury group. Furthermore, these 3 metabolites including Palmitoylethanolamide, Deoxycholic acid and Chenodeoxycholic acid correlated significantly to CLP- and GM-rich genus (P < 0.05). Besides, the lung tissues of CLP group showed more severe inflammatory infiltration and edema, and the mortality rate in the CLP group (10/20) was significantly higher than in the SC group (0/20) (P < 0.001) and GM group (4/20) (P < 0.05).

Conclusion

Our findings showed that GM attenuated sepsis-induced lung injury rats and regulated metabolites related to gut microbiota, which may provide an effective treatment for sepsis patients.

Effects of gabexate mesilate on coagulopathy and organ dysfunction in rats with endotoxemia: a potential use of thrombelastography in endotoxin-induced sepsis

Sepsis and its associated multiple organ failure are related to high mortality in critical patients. Several studies have reported that gabexate mesilate, a synthetic inhibitor of trypsin-like serine protease, protects tissues/organs against injury in the models of endotoxemia. The aim of this study was to examine whether gabexate mesilate could attenuate coagulopathy and organ dysfunction in lipopolysaccharide (LPS)-induced sepsis model by using thrombelastography (TEG). LPS (7.5  mg/kg/h, intravenouly for 4  h) was administered to male adult Wistar rats. Some of the LPS rats received a continuous infusion of gabexate mesilate (10  mg/kg/h, intravenously for 8.5  h) for 30  min before the LPS administration. Variable parameters of hemodynamics, biochemistry, hemostasis and inflammatory response were measured for 6  h after the LPS infusion. TEG variables (R-time, K-time, α-angle, and maximal amplitude) were also measured. The pretreatment of LPS rats with gabexate mesilate significantly attenuated the lung, liver and kidney dysfunction, consumptive coagulopathy, the increases in serum tumor necrosis factor-α, interleukin-6, plasma thrombin-antithrombin complex and plasminogen activator inhibitor-1, and neutrophils infiltration score in lung, liver and kidney, compared with the LPS alone group. In addition, TEG parameters correlated with tissue and liver injury in the late phase of endotoxemia. In particular, a strong negative correlation between maximal amplitude at 4  h and Ln (lactate dehydrogenase) at 6  h after LPS infusion was noted (r = -0.752, P < 0.001, R = 0.566). These results indicate that beneficial effects of anticoagulants (e.g. gabexate mesilate) in endotoxemia could be monitored by TEG per se.

Cysteinyl-leukotriene receptor antagonism blunts the acute hypotensive response to endotoxin in cats

This study evaluated the effects of a cysteinyl-leukotriene-1 (cys-LT(1)) receptor antagonist, zarfirlukast, during feline endotoxemia. Six adult, sexually intact male cats received either placebo or zarfirlukast (10mg, PO) and endotoxin (2 μg/kg/h q 6h) in a cross-over design. Rectal temperature, heart rate, systolic arterial blood pressure, plasma tumor necrosis factor (TNF) activity, interleukin (IL)-6 concentration and urine cys-LT to creatinine ratio were evaluated. The rectal temperature, plasma TNF activity and IL-6 concentrations were significantly higher and systolic arterial blood pressure and heart rate significantly lower after endotoxin infusion. Cats treated with zafirlukast had a significantly higher blood pressure at 4h (P=0.002) compared to placebo. Urine cys-LT to creatinine ratio was significantly greater in the cats treated with zafirlukast compared to placebo (P=0.02). Zafirlukast administration ameliorated the acute hypotensive response to endotoxin in cats, but failed to significantly alter rectal temperature, heart rate or production of TNF and IL-6.

Lack of therapeutic effects of gabexate mesilate on the hepatic encephalopathy in rats with acute and chronic hepatic failure

BACKGROUND AND AIM

Inflammation plays a pivotal role in liver injury. Gabexate mesilate (GM, a protease inhibitor) inhibits inflammation by blocking various serine proteases. This study examined the effects of GM on hepatic encephalopathy in rats with acute and chronic liver failure.

METHODS

Acute and chronic liver failure (cirrhosis) were induced by intraperitoneal TAA administration (350 mg/kg/day for 3 days) and common bile duct ligation, respectively, in male Sprague-Dawley rats. Rats were randomized to receive either GM (50 mg/10 mL/kg) or saline intraperitoneally for 5 days. Severity of encephalopathy was assessed by the Opto-Varimex animal activity meter and hemodynamic parameters, mean arterial pressure and portal pressure, were measured (only in chronic liver failure rats). Plasma levels of liver biochemistry, ammonia, nitrate/nitrite, interleukins (IL) and tumor necrosis factor (TNF)-alpha were determined.

RESULTS

In rats with acute liver failure, GM treatment significantly decreased the plasma levels of alanine aminotransferase (P = 0.02), but no significant difference of motor activity, plasma levels of ammonia, IL-1beta, IL-6, IL-10 and TNF-alpha or survival was found. In chronic liver failure rats, GM significantly lowered the plasma TNF-alpha levels (P = 0.04). However, there was no significant difference of motor activity, other biochemical tests or survival found. GM-treated chronic liver failure rats had higher portal pressure (P = 0.04) but similar mean arterial pressure in comparison with saline-treated rats.

CONCLUSIONS

Chronic GM treatment does not have a major effect on hepatic encephalopathy in rats with TAA-induced acute liver failure and rats with chronic liver failure induced by common bile duct ligation.

Effects of a synthetic protease inhibitor (gabexate mesilate) and a neutrophil elastase inhibitor (sivelestat sodium) on acid-induced lung injury in rats

The present study was designed to examine the combined effects of a synthetic protease inhibitor, gabexate mesilate, with a specific neutrophil elastase inhibitor, sivelestat sodium, on acid-induced lung injury. Adult male Sprague-Dawley rats weighing 300-350 g were anaesthetised intraperitoneally with pentobarbitone sodium and the right jugular vein was cannulated. Following tracheostomy, rats were ventilated mechanically and underwent intratracheal instillation of hydrochloric acid (HCl, 0.1N 1.5 ml/kg) or normal saline. Gabexate mesilate (10mg/kg, i.p.) and/or sivelestat sodium (10mg/kg/h, i.v.) were administered 30 min before HCl instillation. Bronchoalveolar lavage fluid samples were obtained 5h after HCl instillation. In bronchoalveolar lavage fluid, the HCl-induced increases in total nucleated cell counts, neutrophil counts, optical density at 412 nm as an index of pulmonary haemorrhage, concentrations of albumin and cytokine-induced neutrophil chemoattractant (CINC) were significantly attenuated by either gabexate mesilate or sivelestat sodium treatment. Gabexate mesilate or sivelestat sodium treatment also significantly attenuated the wet to dry weight ratio induced by HCl. However, combined treatment with both gabexate mesilate and sivelestat sodium did not show additive effects on HCl-induced lung injury, compared with single treatments. These findings suggested that gabexate mesilate and sivelestat sodium each exhibited protective effects on acid-induced lung injury, but that synergistic effects of both agents are limited in this acid-induced lung injury model.

ONO 3403, a synthetic serine protease inhibitor, inhibits lipopolysaccharide-induced tumor necrosis factor-{alpha} and nitric oxide production and protects mice from lethal endotoxic shock

ONO 3403, a new synthetic serine protease inhibitor, is a derivative of camostat mesilate and has a higher protease-inhibitory activity. The effect of ONO 3403 on lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α and nitric oxide (NO) production in RAW 264.7 macrophage-like cells was examined. ONO 3403 significantly inhibited LPS-induced TNF-α production at a lower concentration than camostat mesilate. It also inhibited LPS-induced NO production. Their inhibition was responsible for the reduced mRNA expression of TNF-α and inducible NO synthase. In LPS-stimulated cells, ONO 3403 prevented the augmentation of MyD88 expression and inhibited the phosphorylation of IκB-α, stress-activated protein kinase (SAPK) and IRF-3, and the production of interferon-β. ONO 3403 abolished the elevation of the extracellular serine protease activity in response to LPS. Further, it reduced the circulating TNF-α level, hepatic injury and mortality in mice receiving an injection of D-galactosamine and LPS. ONO 3403 was suggested to inhibit LPS-induced inflammatory responses via inactivation of MyD88-dependent and independent pathways.

Gabexate mesilate inhibits the expression of HMGB1 in lipopolysaccharide-induced acute lung injury

High mobility group box 1 (HMGB1) is an important late mediator of acute lung injury. Gabexate mesilate (GM) is a synthetic protease inhibitor with some anti-inflammatory action. We aimed to evaluate the effect of GM on HMGB1 in lipopolysaccharide (LPS)-induced lung injury in rats. Prior to the injection of LPS to induce lung injury, rats were administered saline or GM. Injury to the lung and expression of HMGB1, plasminogen activator inhibitor-1 (PAI-1), and protease-activated receptor-2 (PAR-2) were examined. In an accompanying in vitro study, we performed LPS stimulation under GM administration in a mouse macrophage cell line and measured the quantity of HMGB1 and cytokines in the supernatant, and cell signal in the cells. Histologic examination revealed that interstitial edema, leukocytic infiltration, and HMGB1 protein expression were markedly reduced in the GM+LPS group compared wih the LPS group. Furthermore, LPS-induced increases in PAI-1 and PAR-2 activity and in plasma HMGB1 concentrations were lower in the rats given both GM and LPS than in the rats given LPS alone. Release of HMGB1 and cytokines from the cell after the administration of LPS were decreased by GM. Phosphorylation of IκB was inhibited by GM. GM may have inhibited PAI-1 and PAR-2, thereby indirectly inhibiting HMGB1 and reducing tissue damage in the lung. This indicates that GM can inhibit lung injury induced by LPS in rats. GM is a candidate for use in novel strategies to prevent or minimize lung injury in sepsis.

Prognostic factors for fatal outcomes prior to receiving liver transplantation in patients with non-acetaminophen-related fulminant hepatic failure

BACKGROUND AND AIM

Many patients continue to die due to the rapid development of cerebral edema and/or multiple organ failure prior to receiving a liver transplantation.

METHODS

We investigated the prognostic factors associated with 1-week fatal outcomes after the diagnosis of fulminant hepatic failure, which were associated with fatal outcomes prior to receiving liver transplantation, in 104 patients with non-acetaminophen-related fulminant hepatic failure.

RESULTS

With a multivariate logistic regression analysis, age (>40 years), systemic inflammatory response syndrome (SIRS) and plasma prothrombin activities (<or=10%) were significantly associated with fatal outcomes at 1 week after diagnosis in 104 patients. At the time of diagnosis, 50 patients (48%) were in a state of SIRS. Significant differences were observed between patients with and without SIRS regarding the period from the initial symptoms to the diagnosis of fulminant hepatic failure, hepatic coma grade, serum alanine aminotransferase level, serum creatinine level and plasma prothrombin activity. With a multivariate logistic regression analysis, age (>40 years), cause of fulminant hepatic failure (viral hepatitis), plasma prothrombin activity (<or=10%) and no administration of protease inhibitor were significantly associated with the 1-week fatal outcomes of 50 patients with SIRS.

CONCLUSIONS

Patients with SIRS exhibited hepatic failure of increased severity and SIRS may reduce the probability of receiving a liver transplantation. In order to estimate the efficacy of protease inhibitor for patients with SIRS, a prospective randomized trial is required.

Systemic inflammatory response syndrome (SIRS): molecular pathophysiology and gene therapy

In recent years, extensive basic science research has led to a clear understanding of the molecular mechanisms contributing to the pathophysiology of sepsis. Sepsis is now defined as a systemic inflammatory response syndrome (SIRS) in which there is an identifiable focus of infection. SIRS can be also precipitated by non-infective events such as trauma, pancreatitis, and surgery. As a consequence of an overactive SIRS response, the function of various organ systems may be compromised, resulting in multiple organ dysfunction syndrome (MODS) and death. Production and activation of multiple proinflammatory genes are likely to play a key role in the pathogenesis of MODS development. This review article focuses on the molecular mechanisms and components involved in the pathogenesis of severe sepsis. This includes cellular targets of sepsis-inducing bacterial products and their signaling pathways with a major emphasis on transcription factors and new therapeutic approaches to severe sepsis.

Effects of gabexate mesilate on ischemia-reperfusion-induced testicular injury in rats

The aim of this study was to determine the effects of a synthetic serine protease inhibitor, gabexate mesilate (GM), in rats with ischemia-reperfusion (I-R) damage due to unilateral testicular torsion. Thirty male Sprague-Dawley rats were separated into three groups, each containing ten rats. A sham operation was performed in group 1 (control). In group 2 (I-R/untreated), 1 h detorsion of the testis was performed after 6 h of unilateral testicular torsion. In group 3 (I-R/GM), after performing the same surgical procedures as in group II, gabexate mesilate was given intravenously. In all experimental rats, ipsilateral orchiectomies were performed for histological examination and measuring the tissue levels of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px). MDA values and the testicular injury score decreased and SOD, CAT and GSH-Px values increased in the GM-treated group compared to the I-R/untreated group. The Tc-99m pertechnetate uptake ratio and the perfusion index were significantly decreased in the group 2 compared to the group 1 and 3 rats. In group 3, these values were significantly increased compared to group 2. Most of the specimens in the GM-treated group showed grade-I testicular injury. However, the injuries in the I-R/untreated rats varied between grade-III and grade-IV. The results of this study show that GM may play a role in reducing the injury caused by I-R.

Use of low dose dopamine, gabexate mesilate and ulinastatin reduces the water balance and pulmonary complication in thoracic esophagectomy patients

In spite of improvements in surgical technique and perioperative care, severe lung complication remains as the leading cause of morbidity in thoracic esophageal cancer patients who undergo esophagectomy. The purpose of this study was to evaluate the safety and effectiveness of postoperative drug therapy using low dose dopamine, gabexate mesilate, and ulinastatin on postoperative lung complication in esophageal cancer patients. Sixty-one patients operated for esophageal cancer from 1996 to 2000 were treated postoperatively with low dose dopamine (300 microg/kg/h), gabexate mesilate (80 mg/h), and ulinastatin (300 000 unit/day) as a study group. Seventy-four patients operated from 1987 to 1994 served as an historical control group. Various preoperative and perioperative medical parameters and water balance were analyzed. Postoperative pulmonary complications were observed in 26 patients (35.1%) in the control group and three patients (4.9%) in the study group, respectively (P < 0.0001). Preoperative and perioperative variables were not significantly different between the groups. Water balance from operation to postoperative day 3 in the study group was significantly lower than the control group. Postoperative use of low dose dopamine, gabexate mesilate, and ulinastatin significantly reduced pulmonary complications after esophagectomy. This may be partly attributable to negative water balance during the early postoperative days.

Regulation of inflammatory responses by activated protein C: the molecular mechanism(s) and therapeutic implications

Activated protein C (APC), a natural anticoagulant, is formed from protein C by the action of the thrombin-thrombomodulin (TM) complex on the endothelial cell surface. Endothelial protein C receptor augments the activation of protein C by the thrombin/TM system. APC inactivates the activated form of coagulation factors V and VIII in the presence of protein S. Administration of APC reduced the pulmonary vascular injury and hypotension as well as the coagulation abnormalities by inhibiting production of the tumor necrosis factor-alpha (TNF-alpha) in rats given endotoxin (ET). These therapeutic effects of APC could not be attributed to its anticoagulant effects. APC inhibited ET-induced TNF-alpha production in human monocytes by inhibiting activation of nuclear factor K-B and activator protein-1 in vitro. Administration of the human plasma-derived APC ameliorated coagulation abnormalities without any adverse effects in patients with disseminated intravascular coagulation (DIC). Recombinant APC was reported to reduce the mortality of patients with severe sepsis, and the therapeutic effect was more marked in such patients with overt DIC than those without it. These observations strongly suggest that APC plays important roles in the regulation of inflammation as well as coagulation. Both anti-inflammatory and anticoagulant properties of APC might contribute to the therapeutic usefulness in patients with severe sepsis.

Pathophysiological basis of smoke inhalation injury

Smoke inhalation injury results in serious respiratory failure. When smoke inhalation injury is combined with burn injury or pneumonia, the physiological responses are different and more severe than those of smoke inhalation injury alone. Treatment strategies should be planned based on these pathophysiological aspects.

Gabexate mesilate, a synthetic protease inhibitor, inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production by inhibiting activation of both nuclear factor-kappaB and activator protein-1 in human monocytes

Gabexate mesilate, a synthetic protease inhibitor, was shown to be effective in treating patients with sepsis-associated disseminated intravascular coagulation in which tumor necrosis factor-alpha (TNF-alpha) plays a critical role. We demonstrated that gabexate mesilate reduced lipopolysaccharide (LPS)-induced tissue injury by inhibiting TNF-alpha production in rats. In the present study, we analyzed the mechanism(s) by which gabexate mesilate inhibits LPS-induced TNF-alpha production in human monocytes in vitro. Gabexate mesilate inhibited the production of TNF-alpha in monocytes stimulated with LPS. Gabexate mesilate inhibited both the binding of nuclear factor-kappaB (NF-kappaB) to target sites and the degradation of inhibitory kappaBalpha. Gabexate mesilate also inhibited both the binding of activator protein-1 (AP-1) to target sites and the activation of mitogen-activated protein kinase pathways. These observations strongly suggest that gabexate mesilate inhibited LPS-induced TNF-alpha production in human monocytes by inhibiting activation of both NF-kappaB and AP-1. Inhibition of TNF-alpha production by gabexate mesilate might explain at least partly its therapeutic effects in animals given LPS and those in patients with sepsis.

Gabexate mesilate, a synthetic anticoagulant, inhibits the expression of endothelial leukocyte adhesion molecules in vitro

OBJECTIVE

Gabexate mesilate, a synthetic protease inhibitor, has been shown to reduce endotoxin-induced pulmonary vascular injury in an animal model of sepsis by inhibiting leukocyte activation. We examined whether gabexate mesilate inhibits tumor necrosis factor-alpha-induced expression of leukocyte adhesion molecules in cultured endothelial cells.

DESIGN

Prospective, randomized, controlled study.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Cultured human umbilical vein endothelial cell (HUVECs).

INTERVENTIONS

HUVECs were stimulated with tumor necrosis factor-alpha or lipopolysaccharide in the presence or absence of gabexate mesilate. Expression of E-selectin and intercellular adhesion molecule-1 was measured by cellular enzyme-linked immunosorbent assay. Messenger RNA levels of E-selectin and intercellular adhesion molecule-1 were determined by reverse transcription-polymerase chain reaction. DNA-binding activity of p65 in the nuclear extracts was evaluated by enzyme-linked immunosorbent assay. Nuclear translocation of nuclear factor-kappaB induced by tumor necrosis factor-alpha was evaluated by immunocytostaining and Western blot analysis. Degradation and phosphorylation of inhibitor of nuclear factor-kappaB (IkappaB) induced by tumor necrosis factor-alpha were evaluated by Western blot analysis.

MEASUREMENTS AND MAIN RESULTS

Gabexate mesilate inhibited the tumor necrosis factor-alpha-induced increases in the endothelial expression of E-selectin and intercellular adhesion molecule-1 by inhibiting the transcription. Tumor necrosis factor-alpha-induced increase in DNA binding of p65 was inhibited by gabexate mesilate through inhibition of the nuclear translocation of p65. Gabexate mesilate inhibited the tumor necrosis factor-alpha-induced degradation of IkappaBalpha, an inhibitor of nuclear factor-kappaB, by inhibiting phosphorylation of IkappaBalpha in HUVECs.

CONCLUSIONS

Gabexate mesilate inhibited the expression of leukocyte adhesion molecules by inhibiting the nuclear factor-kappaB-mediated transcription in HUVECs. Inhibition of nuclear factor-kappaB activation by gabexate mesilate could be explained by inhibition of degradation of IkappaB. Gabexate mesilate might reduce lipopolysaccharide-induced pulmonary vascular injury not only by inhibiting monocytic tumor necrosis factor-alpha production but by inhibiting the expression of endothelial leukocyte adhesion molecules.

Nafamostat mesilate attenuates radical formation in the rat lung infused with endotoxin

We previously reported direct evidence of respiratory bursting by neutrophils in the pulmonary circulation of endotoxin-infused rats. To evaluate the effect of the protease inhibitor nafamostat mesilate (NM) on leukocyte-mediated radical formation in the pulmonary circulation of rats infused with endotoxin, we observed and measured the number of sticking leukocytes and quantified radical production in the pulmonary circulation of endotoxin-infused rats by means of a fluorescent imaging technique. Plasma C3a (desArg) was also measured using an enzyme-linked immunosorbent assay. Three groups (n = 5) of rats were infused with 4.5 mg/kg/h endotoxin (Et group), 50 microg/kg/h NM + endotoxin (NM group), or physiological saline (Ct group) for 2 h. The number of the leukocytes adhering within pulmonary capillaries, oxygen radical production in the rat pulmonary circulation, and plasma C3a (desArg) were all lower in the NM group than in the Et group. The leukocytes producing oxygen radicals were confirmed to be neutrophils by electron microscopic analysis of cerium deposition. We conclude that NM attenuates plasma C3a formation, neutrophil adherence to pulmonary capillaries, and their production of oxygen radical in rats infused with endotoxin.

Neutrophil elastase inhibitors as treatment for COPD

Chronic obstructive pulmonary disease, characterised by a slowly progressive, irreversible airways limitation, is a major worldwide cause of chronic morbidity and mortality. The imbalance between human neutrophil elastase and endogenous antiproteases may cause excess human neutrophil elastase in pulmonary tissues, which may be considered a major pathogenic factor in chronic obstructive pulmonary disease. Great effort has been devoted to finding a method to restore the balance, resulting in the discovery of potent two-typed small-molecular-weight human neutrophil elastase inhibitors. In the application of chronic obstructive pulmonary disease therapy, the human neutrophil elastase inhibitors mainly focused upon include ONO-5046, MR-889, L-694,458, CE-1037, GW-311616 and TEI-8362 as the acyl-enzyme inhibitors; and ONO-6818, AE-3763, FK-706, ICI-200,880, ZD-0892 and ZD-8321 as the transition-state inhibitors. In this review, various problems that remain to be solved in the clinical use of human neutrophil elastase inhibitors are discussed.

Hepatocyte protection by a protease inhibitor against ischemia/reperfusion injury of human liver

BACKGROUND

Total clamping of the hepatic pedicle can induce profound hepatic ischemia/reperfusion (I/R) injury, which remains a potentially lethal problem after hepatectomy.

STUDY DESIGN

The purpose of this study was to evaluate the efficacy of a protease inhibitor in ameliorating I/R injury of the human liver. In a prospective, randomized, clinical study, 66 patients who underwent liver resection under conditions of continuous inflow occlusion were randomly assigned to three groups: 25 patients were given a synthetic protease inhibitor (gabexate mesilate [GM], 2.0 mg/kg/hr) intravenously starting 24 hours before surgery until postoperative day 3 (preop GM group); 16 were similarly given GM at the beginning of surgery (intraop GM group); and 25 served as controls (without GM group). Laboratory data and intraoperative and postoperative variables were analyzed and plasma levels of cytokines--tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6)--were measured to determine the relationship between surgical stress and hepatic I/R injury.

RESULTS

The three groups of patients were similar in terms of age, gender, preoperative assessments, hepatic inflow occlusion time (approximately 50 minutes), extent of resection (proportion of major and minor hepatectomy), and background liver conditions. Preoperative administration of gabexate mesilate (preop GM group) substantially ameliorated hepatic I/R injury as compared with the other patients (intraop and without GM groups); postoperative serum transaminase levels were notably decreased in association with marked suppression of IL-6 levels in blood circulation during liver surgery. This was accompanied by a lower rate of postoperative complications and no mortality. Gabexate mesilate pretreatment abrogated the positive correlation between postreperfusion hepatocyte injury and hepatic ischemia time.

CONCLUSIONS

Preoperative administration of GM is useful for preventing I/R injury of the human liver, accompanied by suppression of the plasma proinflammatory cytokine IL-6.

Differential cytokine response in host defence mechanisms triggered by gram-negative and gram-positive bacteria, and the roles of gabexate mesilate, a synthetic protease inhibitor

Bacterial infection results in the production of inflammatory mediators and may be involved in the pathogenesis of sepsis and/or systemic inflammatory response syndrome. The effect of lipopolysaccharide (LPS), a major component of the outer surface of Gram-negative bacteria, and Staphylococcal enterotoxin B (SEB), a superantigen of Gram-positive bacteria, on cytokine production in peripheral blood mononuclear cells (PBMCs) was examined. LPS significantly increased the production of proinflammatory and anti-inflammatory cytokines, and SEB enhanced the production of helper T lymphocyte type cytokines. These results illustrated the different responses to Gram-negative and Gram-positive bacterial infections. The effect of gabexate mesilate, a synthetic protease inhibitor, on cytokine production and expression of the toll-like receptor (TLR) was also examined. The results suggest that gabexate mesilate-induced inhibition of tumour necrosis factor-alpha (TNF-alpha) and interleukin-18 (IL-18) production in LPS-stimulated PBMCs is due to the inhibition of the nuclear factor-kappa B activation pathway and/or inhibition of the processing pathway of pro-TNF-alpha and pro-IL-18, not to down-regulation of TLR-2 or TLR-4.

Protective effects of inhaled nitric oxide and gabexate mesilate in lung reperfusion injury after transplantation from non-heart-beat donors

BACKGROUND

The use of lung grafts from non-heart-beat donors (NHBDs) is one way of solving the critical donor organ shortage. Inhaled nitric oxide (NO) and gabexate mesilate (FOY), a protease inhibitor, can attenuate some types of neutrophil-mediated tissue injury. Using an isolated lung ventilation and perfusion model, we studied the effects of these agents on reperfusion injury following lung transplantation from NHBDs.

METHODS

Five groups of minipigs were studied. In group 1(n = 6), the lungs were flushed and harvested after cardiac arrest, and were reperfused for 2 hours after 2 hours of cold ischemia. In group 2 (n = 6), the lungs were harvested after 2 hours of in situ warm ischemia, followed by 2 hours of cold ischemia and 2 hours of reperfusion. In groups 3 (n = 7), 4 (n = 7), and 5 (n = 6), the procedure was the same as in group 2, except in group 3, NO was inhaled before and after ischemia, in group 4, FOY was given intravenously, and in group 5, a combination of inhaled NO and intravenous FOY were administered.

RESULTS

Compared with group 1, group 2 had higher mean pulmonary arterial pressure, vascular resistance, and lower arterial blood oxygen tension. Furthermore, these negative effects of warm ischemia were also reflected in the contents of bronchoalveolar lavage fluid, tissue myeloperoxidase (MPO) activity, histology, and permeability change. Either FOY or NO administration (groups 3 or 4) ameliorated the associated injury. A combination of FOY and NO use (group5) decreased the parameters of lung reperfusion injury measurement to a larger degree than either agent individually.

CONCLUSIONS

The inhaled NO and FOY can protect NHBD lung grafts at an early reperfusion period. Their use in combination has an additive protective effect that might be applied to the protection of NHBD grafts from preservation and reperfusion injury.

Clinical developments for treating ARDS

Acute respiratory distress syndrome (ARDS), is characterised by capillary permeability and pulmonary oedema formation and may complicate a variety of medical and surgical illnesses. As a self-perpetuating state of inflammatory derangement, acute lung injury (ALI)/ARDS is manifest clinically as rapid development of radiographic infiltrates, severe hypoxaemia and reduced lung compliance. Over the years, researchers have made significant progress in elucidating the pathophysiology of this complex syndrome. Therapies targeting specific pathophysiologic steps in the development or persistence of this syndrome are in various stages of laboratory and clinical testing. Results to date have shown nitric oxide (NO) to improve oxygenation in the majority of patients but fail to improve mortality. Surfactant replacement has had limited success in adults, but new formulations and delivery methods may prove beneficial. Several inflammatory mediator-targeted therapies have progressed successfully through early clinical evaluation. Among these, neutrophil elastase inhibitors have shown the most promise and are currently undergoing Phase III trials. Other mediator-targeted therapies, such as prostaglandin E1, IL-10 and platelet activating factor antagonists, have not been found efficacious in large clinical trials of ARDS. However, these therapies, along with coagulation modulators, may have a favourable impact on ARDS by improving outcomes in sepsis, the greatest risk factor for developing this condition. In the interim, supportive care through improvements in mechanical ventilation are beneficial, while specific fluid balance and nutrition strategies may prove advantageous.

Acute respiratory distress syndrome. Potential pharmacologic interventions

Remarkable progress has been made in the past 10 years with regard to understanding the interplay of potent physiologic mediators in patients with acute lung injury. Because there are so many mediators and the interaction of these agents is complex, true insight into the process has been slow in coming. Clinical studies in ARDS, as well as sepsis, the leading cause of ARDS, have increased in number, size, and quality over this same period. Although none of these studies has produced an accepted new therapy for ARDS, each has laid the groundwork for more efficient and more elegant studies of the problem. The stage is now set for the real advances to be brought forward and put to rigorous, efficient clinical testing.

The effects of inhaled nitric oxide, gabexate mesilate, and retrograde flush in the lung graft from non-heart beating minipig donors

BACKGROUND

The use of lung grafts from non-heart-beating donors (NHBD) is one way of solving the donor organ shortage problem. In this experiment, we studied the effect of retrograde flush (RF) from the left atrium before harvest, inhaled nitric oxide (NO), and gabexate mesilate (FOY), a protease inhibitor, in the lung grafts from NHBD.

METHODS

Forty-eight Lee-Sung, small-ear, miniature pigs (15-20 kg) were divided into 24 pairs (donor and recipient) and four groups. The donor lungs were flushed and harvested 90 min after cardiac arrest. No i.v. heparin was administered until the time before flush and harvest. Left single lung transplantation was undertaken, and the recipients were observed for 18 hr. The grafts warm and cold ischemia times were 90 (controlled) and 183+/-23.4 min. Group 1 (untreated control, UC, n=6) had core perfusion through a Swan-Ganz catheter followed by a single, antegrade flush with modified Euro-Collin's solution containing heparin, urokinase, and PGE1. Group 2 (RF group, n=6) had the same as group 1, except that one additive retrograde flush through the left atrium was administered. Group 3 (NO group, n=6) had the same as group 1, except that 20 parts per million (ppm) inhaled NO was administered for the cadaver donors before the graft harvest, and for the recipients after the grafts reperfusion. Group 4 (FOY group, n=6) had the same as group 1, except that the recipients received FOY i.v. infusion from the beginning of the recipient's operation and continuously throughout the experiments.

RESULTS

Compared with the group 1 (control), group 2 (RF) had significantly (P<0.05) lower mean pulmonary artery pressure, pulmonary vascular resistance (PVR), lung wet/dry ratio, histological lung injury score, and higher PaO2/FiO2 and pulmonary dynamic compliance. Group 3 (NO) had significantly lower mean pulmonary arterial pressure, PVR, lung injury score, degree of tissue neutrophils infiltration (histological and myeloperoxidase assay), bronchoalveolar lavage fluid protein content and neutrophils (PMNs) percentage, and higher PaO2/FiO2 and pulmonary dynamic compliance. Group 4 (FOY) had significantly lower PMNs infiltration, lung injury score, wet/dry ratio, bronchoalveolar lavage fluid protein and PMNs percentage, and higher PaO2/FiO2. Group 2 (RF) revealed better gas exchange (PaO2/FiO2) than the control (group 1) at earlier reperfusion periods (1st and 5th hr). On the contrary, group 4 (FOY) had higher PaO2/FiO2 than group 1 only at later period (18th hr). Pathologically, retrograde flush (group 2, RF) inhibited the intravascular thrombi formation more effectively than the NO or FOY treatment. However, the NO or FOY treatment inhibited the neutrophil infiltration more effectively than did the retrograde flush.

CONCLUSION

The retrograde flush, inhaled NO and FOY infusion are beneficial to the protection of the NHBD lung grafts at an early reperfusion period, through different mechanisms. The use of these treatments in combination might help us to find a better way to protect the NHBD grafts against the preservation and reperfusion injury.

Role of leukocytes in spinal cord injury in rats

Spinal cord injury (SCI) is a serious condition that produces life-long disabilities. Only limited therapeutic measures are currently available for its treatment. This review describes the role of leukocytes in pathologic mechanisms of trauma-induced SCI in rats, which contributes to new understanding of the pathologic process involved in SCI and could lead to the development of new therapeutic strategies by which leukocyte activation can be regulated. SCI induced by trauma is a consequence of an initial physical insult that is followed by a progressive injury process which involves various pathochemical events that lead to tissue destruction. Therapeutic intervention in SCI should therefore be directed at reducing or alleviating this secondary process. Although the mechanisms are not fully understood, progressive vascular events, especially activated neutrophil-induced endothelial cell damage, have been shown to be implicated. We have found that some therapeutic agents, which inhibit leukocyte activation directly or indirectly, alleviate the motor disturbances observed in a rat model of SCI. Methylprednisolone (MPS) and GM1 ganglioside, which are the only two pharmacological agents currently clinically available for treatment of acute SCI, do not inhibit neutrophil activation in this rat model. Taken together, these observations raise a possibility that pharmacological agents that inhibit leukocyte activation used in conjunction with MPS or GM1 may have a synergistic effect in the clinical treatment of traumatic SCI in humans.

The prevention of lipopolysaccharide-induced pulmonary vascular injury by pretreatment with cepharanthine in rats

Cepharanthine, a biscoclaurine alkaloid, has been shown to inhibit leukocyte activation in vitro. To determine whether cepharanthine may be of use in the treatment of acute respiratory distress syndrome (ARDS), we investigated its effect on lipopolysaccharide (LPS)-induced pulmonary vascular injury in rats, in which activated leukocytes have been implicated. Intravenous administration of LPS (5 mg/kg) induced pulmonary vascular injury, as indicated by increases in both the pulmonary vascular permeability and the lung wet/dry weight ratio. LPS-induced pulmonary vascular injury was significantly less in animals given cepharanthine (10 mg/kg) intraperitoneally. Cepharanthine significantly inhibited the LPS-induced increases in plasma tumor necrosis factor-alpha (TNF-alpha) concentrations in vivo and significantly inhibited the production of TNF-alpha by LPS-stimulated monocytes in vitro. Cepharanthine also inhibited the functions of activated neutrophils in vitro such as neutrophil elastase release, oxygen radical generation, and neutrophil aggregation, probably by inhibiting a rise in the intracellular free calcium concentration. These findings suggest that cepharanthine prevents LPS-induced pulmonary vascular injury by inhibiting leukocyte activation.

Effects of gabexate mesilate (FOY) on ischemia-reperfusion-induced acute lung injury in dogs

BACKGROUND

To assess the effects of gabexate mesilate (FOY), a protease inhibitor, on a canine model of pulmonary ischemia-reperfusion injury. FOY has been applied clinically to treat acute pancreatitis and disseminated intravascular coagulation (DIC) and has been found to suppress some leukocyte-mediated tissue injuries in both in vitro and in vivo studies.

MATERIALS AND METHODS

DESIGN

Comparison of four experimental groups: group 1 (untreated control, n = 8), unilateral (left) pulmonary ischemia due to perfusion and ventilation obstruction followed by reperfusion, without receiving any specific treatment; group 2 (negative control, sham operation, n = 8), left pulmonary hilar dissection without ischemia; group 3 (FOY posttreatment, n = 8), FOY treatment during the reperfusion stage only; and group 4 (FOY pretreatment, n = 8), FOY treatment before ischemia and then continued during reperfusion.

SETTING

University animal laboratory.

SUBJECTS

Heart-worm-free mongrel dogs (12 to 15 kg body wt) were anesthetized with pentobarbital and mechanically ventilated.

INVESTIGATIONS

Lung ischemia was made by snaring the left pulmonary artery and veins and clamping the bronchus with peribronchial tissue for 90 min followed by reperfusion for 18 h. Animals of the two treatment groups received a 1 mg/kg bolus of FOY at the beginning of reperfusion, with infusion of 2 mg/kg/h of FOY continuously starting 30 min before ischemia (group 4) or after reperfusion (group 3). During this study the following were measured: hemodynamics and aerodynamics, blood gas, bronchoalveolar lavage (BAL) fluid neutrophil percentage and protein concentration, lung wet to dry weight ratio (W/D ratio), myeloperoxidase (MPO) activity of the lung tissue, alveolar neutrophil infiltration, and degree of injury.

RESULTS

This model of lung ischemia-reperfusion induced significant pulmonary hypertension, increased pulmonary vascular resistance, decreased pulmonary dynamic compliance and arterial hypoxemia, increased BAL fluid total protein amount and neutrophil percentage, and increased alveolar neutrophil infiltration, histological injury score, and lung tissue MPO assay (group 1). Animals of the sham operation (negative control, group 2) showed only minimal changes in the above parameters. Treatment with FOY significantly attenuated the injury by decreasing the lung W/D ratio, alveolar neutrophil infiltration, histological injury score, lung tissue MPO assay, BAL fluid neutrophil percentage, and protein amount. Pretreatment with FOY (group 4) attenuated the injury to a significantly greater degree than it did when administered at the reperfusion stage only (group 3), which was reflected by the above-mentioned parameters, and as well significantly improved gas exchange function. FOY treatment was found to have little effect in altering hemodynamics and aerodynamics at most time points in this model of lung injury.

CONCLUSIONS

FOY can attenuate the ischemia-reperfusion-induced acute lung injury in dogs by ameliorating the degree of alveolar membrane permeability change, neutrophil aggregation, and activation. FOY treatment starting before ischemia attenuated this injury to a significantly higher degree than its use after ischemia. However, the effect of FOY may be partial because it cannot alter the hemodynamics or aerodynamics as prominently as other parameters in this type of lung injury. Concomitant use of FOY with other agents will have additive or synergic effects in preventing lung ischemia-reperfusion injury.

Gabexate mesilate, a synthetic protease inhibitor, reduces ischemia/reperfusion injury of rat liver by inhibiting leukocyte activation

OBJECTIVE

To investigate whether gabexate mesilate, a synthetic protease inhibitor with anticoagulant properties, prevents hepatic damage by inhibiting leukocyte activation, we examined its effect on ischemia/reperfusion injury of rat liver in which activated leukocytes play a critical role.

DESIGN

Prospective, randomized, controlled study.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Male Wistar rats weighing 220 to 280 g.

INTERVENTIONS

Hepatic damage was evaluated by changes in bile flow and serum transaminase concentrations after ischemia/ reperfusion. Rats received continuous intravenous infusions of gabexate mesilate (10 mg/kg/hr) or intravenous administration of an inactive derivative of activated factor X (Xa), a selective inhibitor of thrombin generation (3 mg/kg), immediately before the induction of ischemia in the median and left lobes of the liver. To determine whether gabexate mesilate inhibits leukocyte activation, we examined the effects of gabexate mesilate on hepatic concentrations of tumor necrosis factor-alpha and rat interleukin-8 and on hepatic myeloperoxidase activity after ischemia/reperfusion.

MEASUREMENTS AND MAIN RESULTS

Hepatic dysfunction, observed after 60 mins of ischemia/reperfusion, showed a reduction in bile flow. The ischemia/reperfusion-induced decrease in bile flow was prevented by administration of gabexate mesilate. Serum transaminase concentrations increased after hepatic ischemia/reperfusion, peaking 12 hrs after reperfusion. Gabexate mesilate significantly inhibited the ischemia/reperfusion-induced increase in serum transaminase levels seen 12 hrs after reperfusion. Although an inactive derivative of factor Xa inhibited the increases in serum levels of fibrin and fibrinogen degradation products 6 hrs after reperfusion, it did not prevent ischemia/ reperfusion-induced liver injury. Hepatic levels of tumor necrosis factor-alpha, rat interleukin-8, and myeloperoxidase were significantly increased after ischemia/reperfusion. These increases were significantly inhibited by gabexate mesilate but unaffected by an inactive derivative of factor Xa.

CONCLUSION

Gabexate mesilate reduced ischemia/reperfusion-induced hepatic injury not by inhibiting coagulation, but by inhibiting leukocyte activation.

Mechanisms of the systemic inflammatory response

The purpose of inflammation is to combat various agents that may injure the tissues. Conditions such as CPB can often cause systemic inflammation and dysfunction of major organs. Pulmonary, renal, myocardial and intestinal function may suffer various degrees of impairment during and after cardiac surgery. Although changes in major organs usually remain clinically insignificant, severe organ failure is not uncommon. The process of systemic inflammation proceeds through activation of serum proteins, activation of leucocytes and endothelial cells, secretion of cytokines, leucocyte-endothelial cell interaction, leucocyte extravasation and tissue damage. Several anti-inflammatory strategies have already been used, some of which have given promising results pertaining to further reduction in the rate of the inflammation-related complications in cardiac surgical patients.

Effects of a protease inhibitor on reduction of surgical stress in esophagectomy

OBJECTIVE

To evaluate the efficacy of gabexate mesilate (GM) in reducing surgical stress after esophagectomy.

METHODS

In a prospective, randomized, clinical study, 11 patients with squamous cell carcinoma of the esophagus were randomly assigned to two groups: 5 patients were continuously administered gabexate mesilate 1.5 mg/kg per hour from the beginning of anesthesia until the third postoperative day (preop GM group); and 6 patients were administered gabexate mesilate 1.5 mg/kg per hour continuously from the end of surgery and for the same postoperative period (postop GM group). Blood samples were taken from all patients before surgery, immediately after it, and 3 days after surgery. Serum interleukin-6 (IL-6) level, tumor necrosis factor-alpha (TNF-alpha) production, and Mac-1 antigen expression of peripheral blood monocytes were measured. Clinical courses of patients in the two groups were compared.

RESULTS

Time courses of serum IL-6 levels in the preop GM group were significantly lower than those in the postop GM group. Ex vivo TNF-alpha production by lipopolysaccharide (LPS) stimulated monocyte was much higher than that by monocyte without LPS stimulation. Gabexate mesilate showed a little inhibition of TNF-alpha production by monocyte without LPS stimulation. On the other hand, gabexate mesilate significantly inhibited TNF-alpha production by LPS stimulated monocyte. Mac-1 antigen expression by monocyte immediately after operation in the preop GM group was significantly lower than that in the postop GM group. Duration of systemic inflammatory response syndrome was significantly shorter in the preop GM group than in the postop GM group.

CONCLUSIONS

Reduction of systemic inflammatory response syndrome duration after esophagectomy by the continuous administration of gabexate mesilate started before operation may be through the suppression of TNF-alpha production capacity and Mac-1 expression on monocytes immediately after operation, and to suppression of increase in serum IL-6 level.

Spinal cord injury in the rat

Only limited therapeutic measures are currently available for the treatment of spinal cord injury. This review describes the pathologic mechanisms of trauma-induced spinal cord injury in rats, which will contribute to new understanding of the pathologic process leading to spinal cord injury and to further development of new therapeutic strategies. Spinal cord injury induced by trauma is a consequence of an initial physical insult and a subsequent progressive injury process that involves various pathochemical events leading to tissue destruction; the latter process should therefore be a target of pharmacological treatment. Recently, activated neutrophils have been shown to be implicated in the latter process of the spinal cord injury in rats. Activated neutrophils damage the endothelial cells by releasing inflammatory mediators such as neutrophil elastase and oxygen free radicals. Adhesion of activated neutrophils to the endothelial cell could also play a role in endothelial cell injury. This endothelial cell injury could in turn induce microcirculatory disturbances leading to spinal cord ischemia. We have found that some therapeutic agents that inhibit neutrophil activation alleviate the motor disturbances observed in the rat model of spinal cord injury. Methylprednisolone (MPS) and GM1 ganglioside, which are the only two pharmacological agents currently clinically available for treatment of acute spinal cord injury, do not inhibit neutrophil activation in this rat model. Taken together, these observations raise a possibility that other pharmacological agents that inhibit neutrophil activation used in conjunction with MPS or GM1 ganglioside may have a synergistic effect in the treatment of traumatic spinal cord injury in humans.

Gabexate mesilate, a synthetic protease inhibitor, prevents compression-induced spinal cord injury by inhibiting activation of leukocytes in rats

OBJECTIVE

Gabexate mesilate is a synthetic protease inhibitor capable of inhibiting both coagulation and cytokine production by monocytes. To investigate whether gabexate mesilate is useful for the prevention of posttraumatic spinal cord injury, we examined its effect on compression trauma-induced spinal cord injury in rats.

DESIGN

Prospective, randomized, blinded, controlled study.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Male Wistar rats weighing 300 to 350 g.

INTERVENTIONS

Spinal cord injury was induced by applying a 20-g weight extradurally to the spinal cord at the level of the 12th thoracic vertebra for 20 mins. Spinal cord injury was evaluated by assessing the motor function of the rats 24 hrs posttrauma. The accumulation of leukocytes and histologic changes in the injured spinal cord tissue also were examined. Rats received gabexate mesilate (10 or 20 mg/kg i.p.) 30 mins before or after the compressive trauma. The effects of heparin or an inactive derivative of activated factor X (a selective inhibitor of thrombin generation) on compressive trauma-induced spinal cord injury also were examined. Leukocytopenia was induced by the administration of nitrogen mustard.

MEASUREMENTS AND MAIN RESULTS

The motor disturbances observed following traumatic spinal cord compression, evaluated by Tarlov's score, and the accumulation of leukocytes in the injured tissue, evaluated by measuring tissue myeloperoxidase activity, were markedly reduced by leukocyte depletion induced by nitrogen mustard and by pre- or posttreatment of animals with gabexate mesilate. Neither heparin nor the inactive derivative of activated factor X prevented the motor disturbances and the accumulation of leukocytes. Histologic examination demonstrated that intramedullary hemorrhages observed 24 hrs after trauma at the 12th thoracic vertebra were significantly attenuated by nitrogen mustard-induced leukocytopenia and the administration of gabexate mesilate.

CONCLUSIONS

The compression trauma-induced spinal cord injury demonstrated by this model was mainly mediated by leukocytes. Gabexate mesilate prevented spinal cord injury not by inhibiting coagulation, but by inhibiting the activation of leukocytes.