Neutrophil elastase and oxygen radicals enhance monocyte chemoattractant protein- expression after ischemia/reperfusion in rat liver

BACKGROUND: The monocyte chemoattractant protein-1 (MCP-1) is produced during reperfusion injury and induces tissue factor that is the initiator of the clotting cascade. Neutrophil elastase is a crucial mediator of inflammatory tissue damage. Activation of the coagulation system stimulates cytokine production by activated leukocytes. We investigated the effects of neutrophil elastase and oxygen radicals generated by hypoxia associated with microthrombus formation on MCP-1 expression after ischemia/reperfusion in rat liver. METHODS: In vitro MCP-1 production by macrophages after stimulation with human neutrophil elastase (HNE) or oxygen radicals generated by hypoxanthine and xanthine oxidase was examined. Liver ischemia was induced in rats by occluding the portal vein for 30 min. An inhibitor of human neutrophil elastase (ONO-5046*Na, 10 mg/kg) and antithrombin III (AT-III, 250 U/kg) were injected i.v. 5 min before vascular clamping. Serum concentrations of MCP-1 were measured by enzyme-linked immunosorbent assay. RESULTS: Human neutrophil elastase or oxygen radicals significantly enhanced in vitro MCP-1 production by macrophage. Serum MCP-1 concentrations reached a peak at 6 hr after reperfusion and then gradually decreased. However, pretreatment of animals with AT-III or ONO-5046*Na alone resulted in significantly smaller increases in serum concentrations of MCP-1 after reperfusion. Pretreatment with both ONO-5046*Na and AT-III produced additive effects. The combined treatment with ONO-5046*Na and AT-III significantly reduced MCP-1 mRNA in liver after ischemia/reperfusion. CONCLUSIONS: MCP-1 production by macrophages is stimulated by neutrophil elastase and oxygen radicals generated by hypoxia, probably due to microthrombus formation after ischemia/reperfusion of the rat liver.     

Effect of specific neutrophil elastase inhibitor on ischemia/reperfusion injury in rat liver transplantation.

Activated neutrophils have been implicated as playing an important role in ischemia/reperfusion injury of the liver by releasing toxic mediators such as oxygen free radicals and elastases. In the present study, we evaluated the effect of a novel, specific neutrophil elastase inhibitor (ONO-5046) on cold-ischemia/reperfusion injury of the liver allograft in rodents. Livers from male Lewis rats were procured and stored cold (4 degrees C) in lactated Ringer's solution and transplanted orthotopically. Recipients were divided into three groups: Vehicle group, 5-h preservation and vehicle (n = 8); ONO-5046 group, 5-h preservation and administration of ONO-5046 (n = 8); and Control group, minimum preservation only (n = 8). Bile output after reperfusion was significantly larger in the ONO-5046 group compared to the Vehicle group (P < 0.05 or less). Sinusoidal endothelial cell function represented by the serum hyaluronic acid concentration at 120 min after reperfusion of the ONO-5046 group was significantly lower than that in the Vehicle group (17.0 +/- 7.9 vs 36.2 +/- 14.9 ng/ml, P < 0.05), whereas serum transaminase levels 120 min after reperfusion were comparable between the two groups. Liver tissue energy charge 120 min after reperfusion was significantly better in the ONO-5046 group compared to the Vehicle group (P < 0.05). Furthermore, the number of neutrophils infiltrating the allograft after reperfusion was significantly depressed in the ONO-5046 group compared to the Vehicle group (P < 0. 02). These data suggest that the neutrophil elastase might cause liver damage early after reperfusion in cold-stored liver, which can be ameliorated by the administration of a specific neutrophil elastase inhibitor, ONO-5046.     

Neutrophil elastase inhibitor ameliorates reperfusion injury in a canine model of lung transplantation

BACKGROUND: We investigated the effects of neutrophil elastase inhibitor ONO-5046 Na on lung ischemia-reperfusion injury in a canine model of single lung transplantation. METHODS: 24 mongrel dogs, 12 donors and 12 recipients, were used for single lung transplantation. Lung grafts were preserved for 18 h by cold ischemia then transplanted into the left thoracic cavity of recipients. In 6 recipients (ONO group), a bolus of ONO-5046 Na (10 mg/kg) was introduced before reperfusion and followed by continuous infusion (10 mg/kg/h). The remaining 6 recipients (control group) did not receive ONO-5046 Na and thus served as controls. We evaluated lung function and respiratory parameters over 240 min. RESULTS: The total cell number in bronchoalveolar lavage fluid increased significantly in the control group in comparison to that in the ONO group. Histologic scores after 4 h of reperfusion and myeloperoxidase activity were significantly lower in the ONO group than in the control group. CONCLUSION: Neutrophil elastase inhibitor ONO-5046 Na may be useful in ameliorating lung reperfusion injury after transplantation.     

Effect of a neutrophil elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using the left-sided heterotopic canine heart transplantation model.

BACKGROUND: Ischemia/reperfusion injury is a major cause of transplanted heart dysfunction. Several reports have demonstrated that polymorphonuclear neutrophil (PMN) elastase derived from the activated neutrophils might play an important role in this injury. Herein, we investigated the protective effects of PMN elastase inhibitor (ONO-5046 Na) on ischemia/reperfusion injury using a left-sided canine heterotopic heart transplantation model. METHODS: We used 10 pairs of adult beagle dogs. The donor heart was transplanted heterotopically into the left thoracic cavity of the recipient without cardiopulmonary bypass. A bolus of ONO-5046 Na (10 mg/kg) was introduced intravenously to 5 recipients (group II) at 15 minutes before reperfusion and was followed by continuous infusion (10 mg/kg per hour) for 180 minutes. Five dogs (group I) did not receive ONO-5046 Na and thus served as a control. After reperfusion, we evaluated transplanted heart function and obtained blood samples from the coronary sinus over a 360-minute period. RESULTS: E(max) and pre-load recruitable stroke work in group II showed significantly better recovery than group I. Blood levels of PMN elastase, creatine kinase MB, lactate and inflammatory cytokines (tumor necrosis factor-alpha, interleukin-6, interleukin-8) were significantly lower in group II. Depletion of myocardial concentration of adenosine triphosphate at 120 minutes after reperfusion and myocardial water content was significantly lower in group II. CONCLUSIONS: ONO-5046 Na, which inhibits PMN elastase, could reduce ischemia/reperfusion injury in heart transplantation. These results indicate that clinical application of ONO-5046 Na should be considered.     

Hepatic ischemia-reperfusion promotes liver metastasis of colon cancer

BACKGROUND: The effects of hepatic ischemia/reperfusion (I/R) on liver metastasis have not been fully examined. We examined hepatic I/R and liver metastasis of colorectal cancer in a rat model; we also quantitated expression of E-selectin (ELAM-1) mRNA after I/R. MATERIALS AND METHODS: Rats underwent 30 or 60 min of 70% partial hepatic ischemia. After 60 min of reperfusion, rat colon adenocarcinoma cells (RCN-H4) were inoculated intrasplenically. The number of tumor nodules on the liver surface was determined 3 weeks later. Expression of E-selectin mRNA was determined at 1, 3, and 6 h after ischemia by quantitative RT-PCR. RESULTS: Hepatic I/R promoted liver metastasis of RCN-H4 and induced the expression of E-selectin mRNA in both clamped and unclamped liver lobes. The number of tumor nodules and the expression of E-selectin mRNA after 60 min of ischemia was greater than that after 30 min. CONCLUSIONS: Hepatic I/R, especially with a long duration of ischemia, induces expression of E-selectin and promotes liver metastasis of colon cancer in rats.     

Stimulation of haematogenous liver metastases by ischaemia-reperfusion in rats.

OBJECTIVE: To find out whether hepatic ischaemia-reperfusion stimulates hepatic tumour metastases using a cell line of rat ascitic hepatoma (AH130). DESIGN: Prospective experimental study. SETTING: University laboratories, Japan. MATERIALS: 118 male Donryu rats. INTERVENTION: After laparotomy alone (group 1, n = 35) or laparotomy and 20-minutes ischaemia (group 2, n = 34) or laparotomy and 30-minutes ischaemia (group 3, n = 34) of the median and left hepatic lobes, the animals were given either an intraportal injection of 1 x 10(5) or an intravenous injection of 1 x 10(6) viable AH130 cells. MAIN OUTCOME MEASURES: 10 days after inoculation of tumour cells the number of nodules on the surface of the right lobe and of the median plus left lobes were separately counted for each liver. RESULTS: Irrespective of the route of tumour inoculation in group 1, there was no significant difference in the number of tumours/g liver between the right and the median plus left lobes. However, in groups 2 and 3, the number of tumours/g liver in the median plus left lobes was significantly higher than in the right lobe (p < 0.05). Furthermore, in the median plus left lobes, animals who had had 30 minutes of ischaemia had significantly more tumours than those in the other two groups (p < 0.01). CONCLUSION: Hepatic ischaemia-reperfusion may increase the risk of development of haematogenous liver metastases, by stimulating tumour cell-endothelial cell interactions.     

Protective effects of ONO-5046*Na, a specific neutrophil elastase inhibitor, on postperfusion lung injury

Background. Polymorphonuclear neutrophil elastase might contribute to postperfusion lung injury, so we evaluated the protective effect of ONO-5046·Na, a specific inhibitor of polymorphonuclear neutrophil elastase, against such an injury.

Methods. The study was done using 8 mongrel dogs that received ONO-5046·Na (15 mg/kg per hour) (group O) and 8 control dogs (group C), all of which had 1 hour of partial bypass and 5 hours of observation.

Results. The respiratory index showed no significant changes in group O, but increased significant in group C (1.4 ± 2.0 versus 5.1 ± 4.7, p = 0.0047). Pulmonary extravascular water volume increased markedly in group C but only slightly in group O (group C 20.6 ± 8.7, group O 11.2 ± 2.7 mL/kg; p = 0.0005). Blood concentrations of polymorphonuclear neutrophil elastase and interleukin-6 showed more than a tenfold increase in group C (PMN elastase, group C 12.9 ± 12.8, group O 2.4 ± 1.3 ng/mL; IL-b, group C 11.0 ± 9.3, group O 2.9 ± 3.8 pg/mL; p < 0.05) but were only slightly higher in group O. Histologic examination revealed interstitial and intraalveolar edema in group C, but group O was virtually normal.

Conclusions. ONO-5046·Na inhibits polymorphonuclear neutrophil elastase and maintains better pulmonary function, so it should reduce postperfusion lung injury.     

The effects of a specific neutrophil elastase inhibitor (ONO-5046) in pulmonary ischemia–reperfusion injury

Ischemia-reperfusion injury is a significant problem in lung transplantation. Polymorphonuclear elastase derived from neutrophils plays a major mechanistic role in this process. Hence, we have investigated the effects of ONO-5046, a neutrophil elastase inhibitor, on ischemia-reperfusion injury. Fifteen rabbits were divided into three groups: 2 h of single left-lung perfusion (control group, n=3); 2 h of ischemia followed by 2 h of reperfusion (ischemic group, n=6); and drip intravenous administration of ONO-5046 during the 2 h of ischemia and 2 h of reperfusion (ONO-5046 group, n=6). Hemodynamic parameters were determined and a histopathological examination of the lung was performed. In the ONO-5046 group, arterial oxygen pressure, cardiac output, and tissue blood perfusion were higher and pulmonary vascular resistance was lower than in the ischemic group. The ONO-5046 group also showed large decreases in neutrophil infiltration, pulmonary edema, and intra-alveolar hemorrhage. Treatment with ONO-5046 improves lung function in a rabbit-lung ischemia-reperfusion model.     

Pretreatment of acid-induced lung injury with specific neutrophil elastase inhibitor ONO-5046 did not exasperate the subsequent bacterial lung infection by Pseudomonas aeruginosa

Patients with acid lung injuries are at high risk for bacterial pulmonary infections which commonly occur several days after the acid aspiration. We reported that a specific neutrophil elastase inhibitor ONO-5046 inhibited the multi-organ injury caused by acid-instillation into the lung. In this study, we evaluated the effect of ONO-5046 on lung infection by Pseudomonas aeruginosa (PAO-1:Ps.) following acid-induced lung injury in rat lungs. Animals received 0.2 ml of hydrochloric acid (pH = 1) into the right lungs. Pretreated animals were administered ONO-5046 (30 mg.kg-1) i.v. 15 min. before acid instillation. Other groups received vehicle (saline). Twenty four hours later, they were instilled with 0.1 ml of Ps. 1 x 10(8) cfu into the left lungs. Four hours after bacterial challenge, the animals were deeply anesthetized and killed. Bronchoalveolar lavage was done on each lung separately to evaluate neutrophil elastase activity, neutrophil number and protein permeability of lung endothelium and epithelium. The numbers of Ps. in the lungs were measured. In the Ps.-instilled lung, the number of Ps. or the protein permeability was not increased with ONO-5046 pretreatment compared with those in the untreated group. Pretreatment inhibited the exasperation of the protein permeability indirectly caused by Ps. infection in the acid-instilled lung. It was indicated that ONO-5046 could inhibit the indirect lung injury caused by acid-instillation into the lung without aggravating the subsequent bacterial infection.     

The effects of a neutrophil elastase inhibitor (ONO-5046.Na) and neutrophil depletion using a granulotrap (G-1) column on lung reperfusion injury in dogs.

BACKGROUND: Activated neutrophils are reported to be closely involved in ischemia-reperfusion injury after lung transplantation. We investigated the beneficial effects of a new recombinant specific neutrophil elastase inhibitor, ONO-5046.Na, and an extracorporeal-type granulotrap (G-1) column on ischemia-reperfusion lung injury, by using an in situ warm lung ischemia model in dogs. METHODS: Warm ischemia was induced for 3 hours by clamping the pulmonary arteries and veins. The left main bronchus was bisected and reanastomosed prior to reperfusion. The left lung was collapsed for 3 hours. A total of 27 adult mongrel dogs were divided into three groups: the control group (n = 9) treated with a saline vehicle; the ONO group (n = 9), in which ONO-5046.Na was continuously administrated from before induced ischemia and to ending 2 hours after reperfusion; and the G-1 group (n = 9), in which a G-1 column was applied for 90 minutes starting 30 minutes before reperfusion under passive bypass support. RESULTS: Circulating neutrophils in the G-1 group decreased significantly (p<.05) compared to preischemia, and significantly decreased compared with the other groups after reperfusion. Oxygenation was improved actually and pulmonary vascular resistance was kept lower level after the administration of ONO-5046.Na. The increase of lung weight was significantly ameliorated in both the G-1 and ONO groups. In the histopathological study, lungs from the control group demonstrated diffuse alveolar edema, neutrophil infiltration, massive alveolar exudate and hemorrhage, and thickening of the interstitium. Lungs from the G-1 group showed mild swelling of the alveolar wall and neutrophil infiltration. Lungs from the ONO group showed virtually no abnormalities. CONCLUSION: This study demonstrated that a neutrophil elastase inhibitor and neutrophil depletion prevented lung reperfusion injury. These treatments may prevent ischemia and reperfusion injury in lung transplantation.     

Effect of a specific synthetic inhibitor of neutrophil elastase (ONO-5046) on the course of acute hemorrhagic pancreatitis in dogs

In acute pancreatitis, particularly in severe cases, polymorphonuclear neutrophil (PMN) elastase induces tissue damage in remote organs such as the lung, as well in the pancreas itself. Therefore, we examined the therapeutic effect of a specific synthetic inhibitor of PMN elastase (ONO-5046: Ono Pharmaceuticals, Osaka, Japan) on the lung, liver, and kidney, as well as pancreas, in severe hemorrhagic pancreatitis in dogs. Acute hemorrhagic pancreatitis was induced by the injection of a mixture of autologous bile and porcine trypsin into the main pancreatic duct. Lipopolysaccharide (LPS) was administered intravenously as a septic challenge. Two animal groups were used. In one group, continuous infusion of ONO-5046 was started prior to the injection of LPS (ONO group). In the other group (control), saline was infused instead. At the end of the experiment (330 min after the injection of bile and trypsin), the pancreas revealed severe hemorrhagic pancreatitis, and a large amount of bloody ascites had accumulated in the peritoneal cavity. The white blood cell count was markedly reduced in response to the induction of pancreatitis, and was decreased further by the septic attack, irrespective of the administration of ONO-5046, although the count increased again in the ONO group. Serum levels of amylase and α₂-macroglobulin-trypsin complex increased similarly in both groups following administration of bile and trypsin. Serum Ca levels decreased in both groups. At the end of the experiment, the wet weight of the lung was slightly higher in the control group (without ONO-5046). Microscopically, the pancreas showed severe hemorrhage accompanied by extensive interstitial edema in both groups. The lung and liver demonstrated mild infiltration of inflammatory cells in the interstitium in both groups, although the inflammatory change in the liver was slightly milder in the ONO group. These findings indicate that severe hemorrhagic pancreatitis cannot be alleviated by the administration of a specific inhibitor of PMN elastase alone, although this may lessen damage to remote organs such as the liver and lung. The white blood cell count decreased markedly after the induction of acute pancreatitis, and much more after a septic challenge. This seems to be closely related to the accumulation of bloody ascites in the peritoneal cavity. Received for publication on Aug. 23, 1997; accepted on April 30, 1998     

Neutrophil Elastase Inhibitor, ONO-5046, Modulates Acid-induced Lung and Systemic Injury in Rabbits

Background: Acid instillation leads to direct lung and to secondary systemic organ injury, probably via activated macrophages and neutrophils. This study investigated the effects of neutrophil elastase on organ injury after unilateral lung acid instillation by administrating a specific neutrophil elastase inhibitor, ONO-5046, before acid instillation.

Methods: Three groups of anesthetized rabbits (n = 12 in each group) underwent tracheostomies, and instillations were made into their right lower lobe airspaces with either phosphate buffered saline (pH, 7.4; volume, 1.2 ml/kg; n = 12) or HCl (pH, 1.25; volume, 1.2 ml/kg; n = 24). In half of the acid-instilled rabbits, ONO-5046,10 mg/kg, was given intravenously 15 min before the HCl instillation, and then 10 mg [center dot] kg sup -1 [center dot] h sup -1 of the drug was continuously infused throughout the experiment. The other groups of animals received the vehicle intravenously. Anesthesia and mechanical ventilation was continued for 8 h, whereas arterial blood gases were sampled intermittently. Eight hours after saline or acid instillation, the animals were killed, and their lungs, heart, kidneys, liver, and small intestines were harvested. Wet-to-dry weight ratios (W/D) and myeloperoxidase (MPO) assays of these organs were done, and elastase assays on the bronchoalveolar lavage fluids (BALF) obtained from each lung also were performed.

Results: Pretreatment with ONO-5046 attenuated the physiologic changes seen in the vehicle-treated animals. Significant decreases in W/D of the noninstilled lungs and of the small intestine and normalization of the oxygenation of the experimental animals occurred. The ONO-5046 pretreatment did not affect the neutrophil sequestration in the lungs or in the other organs as determined by neutrophil counts in BALF and by the MPO assays.     

Benefical effect of neutrophil elastase inhibitor on renal warm ischemia-reperfusion injury in the rat

Renal ischemia-reperfusion (I/R) injury is a significant problem in renal transplantation. Neutrophils play an important role in renal I/R injury. Several reports have demonstrated that neutrophil elastase derived from the activated neutrophils might play an important role in this injury. We investigated the effect of a neutrophil elastase inhibitor in renal I/R injury. Male Lewis rats (270-320 g) were used in the model. The right kidney was harvested and the left renal artery and vein were clamped at laparotomy. The kidney was reperfused after 90 minutes of ischemia. Neutrophil elastase inhibitor (ONO-5046: 30 mg/kg) was delivered intravenously before ischemia and after reperfusion to prevent neutrophil activation. In the nontreatment I/R group, no hosts survived 4 days. However, after treatment with neutrophil elastase inhibitor, 3 of 10 rats in the I/R group, survived more than 7 days. These results demonstrated that treatment with neutrophil elastase inhibitor ameliorated renal I/R injury.     

Pilot study of the effects of ONO-5046 in patients with acute respiratory distress syndrome

Evidence has linked neutrophil elastase to acute respiratory distress syndrome (ARDS), suggesting that inhibiting the activity of this enzyme could prevent the development and progression of ARDS. However, few clinical trials have examined this notion. We therefore examined the effects of ONO-5046 (sivelestat, a specific inhibitor of neutrophil elastase; sodium N-[2-[4-(2,2-dimethylpropionyloxy) phenylsulfonylaminobenzoyl]amino-acetate tetrahydrate]) in a randomized, double-blinded trial in patients with ARDS. We randomly assigned 24 patients with ARDS to groups that received conventional therapy without or with sivelestat (0.2 mg. kg(-1). h(-1)) for 14 days. The variables of interest associated with clinical outcome were the duration of mechanical ventilation; changes in oxygenation from baseline; changes in cytokine levels from baseline; number of patients alive at 30 days who did not need mechanical ventilation; and mortality rate. The length of intensive care unit stay, number of ventilation days, and mortality rates did not statistically differ between groups. ARDS was more persistent in the control than in the sivelestat group (control, 19.5 +/- 7.4 days; sivelestat, 13.5 +/- 5.9 days; P = 0.039). Neutrophil elastase activity significantly differed between groups at 72 h after treatment. Levels of interleukin-6 were lower in the sivelestat group than in the controls at 24, 48, and 72 h after treatment. ONO-5046 apparently did not affect survival or the duration of mechanical ventilation.     

Experimental study of the effects of deletion variant of hepatocyte growth factor on hepatic ischaemia-reperfusion injury

BACKGROUND: Hepatic ischaemia-reperfusion (IR) injury is still a serious complication following liver surgery. The effect of the deletion variant of hepatocyte growth factor (dHGF) on hepatic IR injury was examined in rats. METHODS: Male Wistar rats were divided into two groups after 90 min of partial liver ischaemia: the dHGF group which was given dHGF 0.5 mg/kg intravenously immediately after reperfusion, followed by 0.5 mg/kg every 12 h, and the control group, which received vehicle buffer only. Serum chemistry, histopathological findings and liver weights were compared between the groups. RESULTS: In the dHGF group, the increase in serum alanine transaminase and hyaluronic acid levels was significantly reduced, and the serum albumin level increased after reperfusion. The extent of hepatic necrosis 24 h after reperfusion was decreased in the dHGF group. Moreover, the proportion of terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labelling-positive hepatocytes 6 h after reperfusion was reduced in the dHGF group. The non-ischaemic-, ischaemic- and whole-liver weight : body-weight ratio significantly increased in the dHGF group after reperfusion. The proportion of proliferating cell nuclear antigen-positive hepatocytes in the dHGF group markedly increased after 6 h after reperfusion in the non-ischaemic lobes, while in the ischaemic lobes it increased 24 h after reperfusion. CONCLUSION: These data suggest that dHGF not only improves recovery from IR injury, but also accelerates recovery from these injuries. dHGF may be an effective pharmacological agent for prevention and treatment of hepatic IR injury.     

Neutrophils mediate acute lung injury in rabbits: role of neutrophil elastase

We investigated the roles of neutrophil and neutrophil elastase in acute lung injury (ALI) to elucidate the mechanism of ALI. We designed two protocols. Protocol I: Experimental ALI was induced by endotoxin (0.02 mg/kg) and platelet-activating factor (8 microg/kg/4 h) in untreated rabbits (control group I), in neutropenic rabbits pretreated with nitrogen-N-oxide hydrochloride, and in untreated rabbits infused with a neutrophil elastase inhibitor (ONO-5046; 20 mg/kg/4 h). Protocol II: ALI was induced by smaller doses of endotoxin (0.015 mg/kg) and platelet-activating factor (7 microg/kg/4 h) than those used in protocol I in untreated rabbits (control group II), in neutrophilic rabbits pretreated with human recombinant granulocyte colony-stimulating factor, and in neutrophilic rabbits infused with ONO-5046 (as in protocol I). The severity of ALI was assessed by the protein concentration, the elastase activity in the bronchoalveolar lavage fluid, and the histologic pulmonary edema ratio. The degree of pulmonary neutrophil accumulation was assessed by pulmonary myeloperoxidase activity and histological findings. Both ALI and pulmonary neutrophil accumulation were suppressed by neutropenia (protocol I), while they were exacerbated by neutrophilia (protocol II). The neutrophil elastase inhibitor could suppress ALI, but it could not suppress pulmonary neutrophil accumulation in both untreated and neutrophilic rabbits (protocols I and II). These findings indicate that neutrophils play an important role in the pathogenesis of ALI via neutrophil elastase.     

Selective portal clamping to minimize hepatic ischaemia-reperfusion damage and avoid accelerated outgrowth of experimental colorectal liver metastases

BACKGROUND: Temporary vascular clamping during local ablation for colorectal liver metastases increases destruction volumes. However, it also causes ischaemia-reperfusion (IR) injury to the liver parenchyma and accelerates the outgrowth of microscopic tumour deposits. The aim of this study was to investigate the effects of selective portal clamping on hepatocellular damage and tumour growth. METHODS: Mice carrying pre-established hepatic colorectal micrometastases underwent either simultaneous clamping of both the portal vein and the hepatic artery or selective clamping of the portal vein to the median and left liver lobes for 45 min. Sham-operated mice served as controls. Hepatic injury and tumour growth were assessed over time. RESULTS: Standard inflow occlusion resulted in a rise in liver enzymes, a local inflammatory response and hepatocellular necrosis. The outgrowth of pre-established micrometastases was accelerated three- to fourfold in clamped compared with non-clamped liver lobes (27.4 versus 7.8 per cent, P < 0.010). Conversely, selective portal clamping induced minimal liver injury, tissue inflammation or hepatocellular necrosis, and completely stopped the accelerated outgrowth of micrometastases. CONCLUSION: Selective portal clamping does not induce liver tissue damage or accelerate micrometastasis outgrowth and may therefore be the preferable clamping method during local ablative treatment of hepatic metastases.     

Hepatic ischemia/reperfusion injury is prevented by a novel matrix metalloproteinase inhibitor, ONO-4817

BACKGROUND: Matrix metalloproteinases (MMPs) play an important role in inflammation and neoplastic invasion and metastasis. Little is known about the effects of MMP inhibitors on hepatic ischemia/reperfusion injury. The aim of this study is to examine the inhibitory effects of ONO-4817 (oral inhibitor of MMPs) in rats. METHODS: Hepatic ischemia/reperfusion was induced in male Wister rats by clamping the portal vein and hepatic artery. The animals were randomized into an ONO-4817 group (300 mg/kg body weight per/day) and a vehicle group by oral gavage of a test substance. Serum alanine aminotransferase, histologic changes, gelatinolytic activity, MMP-2 and MMP-9 activities, tissue inhibitor of metalloproteinase 2 (TIMP-2) messenger RNA (mRNA) levels, and mRNA and serum levels of tumor necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta) were measured in both groups. RESULTS: ONO-4817 prevented ischemia/reperfusion injury to the hepatocytes as shown by significant reductions of serum alanine aminotransferase and less severe histologic changes. Gelatinolytic activity was inhibited markedly in the liver of the ONO-4817 group as demonstrated by film in situ zymography. MMP-9 and MMP-2 activities also were inhibited in the ONO-4817 group as shown by gelatin zymography. TIMP-2 mRNA levels showed no significant differences between the 2 groups. TNFalpha mRNA showed no downregulation, but IL-1beta mRNA was downregulated in the liver of the ONO-4817 group 1 to 3 hours after reperfusion. Serum levels of TNFalpha and IL-1beta showed a significant decrease in the ONO-4817 group, compared with the vehicle group after reperfusion. CONCLUSIONS: Hepatic ischemia/reperfusion injury was improved by a novel MMP inhibitor, ONO-4817, not only by inhibition of gelatinolytic activity but also by a decrease in release of inflammatory cytokines.     

A novel inhibitor of inducible nitric oxide synthase (ONO-1714) prevents critical warm ischemia-reperfusion injury in the pig liver

BACKGROUND: Recently, a novel inhibitor of inducible nitric oxide synthase, ONO-1714, was developed. We evaluated the effect of ONO-1714 on a critical warm I/R model of the pig liver. METHODS: Pigs were subjected to 180 min of hepatic warm I/R under the extracorporeal circulation. We investigated the time course of changes in the serum NO2- + NO3- (NOx), the cellular distribution of endothelial and inducible nitric oxide synthase, thrombocyte-thrombi, and nitrotyrosine by immunohistochemistry. The hepatic tissue blood flow (HTBF) was measured continuously using a laser-Doppler blood flowmeter. RESULTS: ONO-1714 at 0.05 mg/kg improved the survival rate from 54 (control group) to 100%. The serum NOx levels in the ONO-1714 group were significantly lower than those in the control group at 1, 1.5, 2, 3, and 6 hr after reperfusion. The serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels of the ONO-1714 group were significantly lower than the control group, and the HTBF of the ONO-1714 group was significantly higher than the control group. The formation of thrombocyte-thrombi and nitrotyrosine after reperfusion was significantly lower in the ONO-1714 group. CONCLUSIONS: These results indicated that ONO-1714 improved the survival rates and attenuated I/R injury in a critical hepatic warm I/R model of the pig. ONO-1714 will be beneficial for hepatectomy or liver transplantation in the clinical field.