Partial Splenic Embolization in a Patient with Hemophilia A and Severe Thrombocytopenia: A Case Report

We report a patient with hemophilia A who underwent partial splenic embolization (PSE) for severe thrombocytopenia secondary to portal hypertension-induced splenomegaly, resulting in a stable long-term quality of life. The patient was diagnosed with hemophilia A and unfortunately contracted human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) from blood products. He subsequently developed progressive splenomegaly due to portal hypertension from chronic HCV, resulting in severe thrombocytopenia. PSE was performed because he had occasional subcutaneous bleeding and needed to start interferon (IFN) and ribavirin (RBV) treatment for curing his HCV infection at that time. His platelet counts increased, and no serious adverse events were observed. Currently, he continues to receive outpatient treatment, regular factor VIII (FVIII) replacement therapy for hemophilia A, and antiretroviral therapy for HIV infection. Vascular embolization has been reported to be an effective and minimally invasive treatment for bleeding in hemophilia patients. PSE also provided him with a stable quality of life without the side effects of serious infections and thrombocytopenia relapses. We conclude that PSE is a promising therapeutic option for patients with hemophilia A.

Glycosylated ferritin as an improved marker for post-transfusion iron overload

Red blood cell (RBC) transfusion is an effective therapy for anemia, but repeated transfusions may cause iron overload-related damage to various organs. Iron chelation therapy, now widely available for patients who have received transfusions, is expected to reduce organ damage even in patients who received many transfusions. Therefore, determining when to start iron chelation therapy is important. In guidelines for iron chelation therapy, the serum ferritin level has been widely accepted as a practical marker for estimating iron overload. However, guidelines recommend multiple measurements of serum ferritin, because levels often fluctuate. Here, we investigated the usefulness of glycosylated ferritin as a marker of iron overload using a cohort consisted of 103 patients who had a total ferritin value over 1000 ng/mL. We found that the volume of RBCs transfused was clearly associated with the glycosylated ferritin level. We also found that acute inflammation, as represented by C-reactive protein values, was associated with increased non-glycosylated ferritin and that patients with hematopoietic diseases had higher glycosylated ferritin levels, possibly because of repeated RBC transfusions. We thus conclude that glycosylated ferritin may be an improved marker for predicting iron overload status.

[Spontaneous remission of acquired factor XIII inhibitor concurrent to development of IgA-λ type multiple myeloma]

Coagulation factor XIII is a fibrin-stabilizing factor that leads to the crosslinking of fibrin when activated by thrombin. Acquired factor XIII inhibitor is caused when antibodies are generated against factor XIII, reducing its activity. Here we report a case of acquired factor XIII inhibitor. Although prednisolone was administered, factor XIII activity was not recovered. Interestingly, the activity normalized following the onset of multiple myeloma. The presence of inhibitors was evaluated in the patient's plasma by absorption tests and enzyme-linked immunosorbent assay. Immunoglobulin G inhibitors of factor XIII were present at admission, but later decreased with the onset of the IgA-λ-type myeloma. Thus, it is possible that the level of factor XIII inhibitors and polyclonal immunoglobulins could have been suppressed by the progression of myeloma, resulting in the normalization of factor XIII activity.

A Novel Platelet Activating Factor Antagonist, SM-12502, Attenuates Endotoxin-induced Disseminated Intravascular Coagulation and Acute Pulmonary Vascular Injury by Inhibiting TNF Production in Rats

Adult respiratory distress syndrome and disseminated intravascular coagulation are important pathologic conditions affecting the outcome of patients with sepsis. To elucidate the possible therapeutic efficacy of SM-12502, a novel platelet activating factor antagonist, on acute lung injury and disseminated intravascular coagulation in sepsis, we investigated the effect of SM-12502 on an endotoxin (ET)-induced septic model in rats. SM-12502 prevented ET-induced increases in pulmonary vascular permeability and ET-induced histologic changes, such as leukocyte infiltration and pulmonary interstitial edema, 6 h following the administration of ET (5 mg/kg). SM-12502 also inhibited the decrease in fibrinogen and the increase in fibrin and fibrinogen degradation products observed following ET administration. SM-12502 prevented increases in the serum concentration of tumor necrosis factor (TNF) 90 min following ET administration in vivo, and significantly inhibited the production of TNF-α by ET-stimulated monocytes in vitro.

These findings suggest that SM-12502 attenuates the actions of endotoxin by the inhibition of TNF production

Effects of Plasma Kallikrein Specific Inhibitor and Active-site Blocked Factor VIIa on the Pulmonary Vascular Injury Induced by Endotoxin in Rats

The acute respiratory distress syndrome (ARDS) is a serious complication of sepsis. To evaluate the role of the coagulation system in the pathogenesis of ARDS in sepsis, we examined the effects of the administration of a synthetic plasma kallikrein specific inhibitor (PKSI) and of active-site blocked factor VIIa (DEGR-VIIa) on the pulmonary vascular injury induced by E. coli endotoxin (ET) in rats. Administration of PKSI prevented the pulmonary vascular injury induced by ET as well as pulmonary histological changes in animals administered ET, but it did not affect the intravascular coagulation. The opposite effect was seen with DEGR-VIIa, which prevented the intravascular coagulation but not the pulmonary vascular injury. PKSI did not inhibit the activation of the complement system induced by ET leading to the activation of neutrophils.

Findings suggest that PKSI may prevent the pulmonary vascular injury induced by ET by inhibiting kallikrein, which activates the neutrophils. The intrinsic pathway of coagulation may be more important than the extrinsic pathway in the pulmonary vascular injury produced byET.

Recombinant Human Soluble Thrombomodulin Reduces Endotoxin-Induced Pulmonary Vascular Injury Via Protein C Activation in Rats

Adult respiratory distress syndrome (ARDS) is a serious complication of disseminated intravascular coagulation (DIC) or multiple organ failure. To determine whether recombinant soluble human thrombomodulin (rsTM) may be useful in treating ARDS due to sepsis, we investigated the effect of rsTM on lipopolysaccharide (LPS)-induced pulmonary vascular injury in rats. The intravenous administration of rsTM prevented the increase in pulmonary vascular permeability induced by LPS. Neither heparin plus antithrombin III (AT III) nor dan- syl Glu Gly Arg chloromcthyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, prevented LPS-induced vascular injury. The agents rsTM, heparin plus AT III, and DEGR-Xa all significantly inhibited the LPS-induced intravascular coagulation. Recombinant soluble TM pretreated with a monoclonal antibody (moAb) that inhibits protein C activation by rsTM did not prevent the LPS-induced vascular injury; in contrast, rsTM pretreated with a moAb that does not affect thrombin binding or protein C activation by rsTM prevented vascular injury. Administration of activated protein C (APC) also prevented vascular injury. LPS-induced pulmonary vascular injury was significantly reduced in rats with leukopenia induced by nitrogen mustard and by ONO-5046, a potent inhibitor of granulocyte elastase.

Results suggest that rsTM prevents LPS-induced pulmonary vascular injury via protein C activation and that the APC-induced prevention of vascular injury is independent of its anticoagulant activity, but dependent on its ability to inhibit leukocyte activation.

Activated Protein C Inhibits Lipopolysaccharide-Induced Tumor Necrosis Factor-α Production by Inhibiting Activation of both Nuclear Factor-κB and Activator Protein-1 in Human Monocytes

Activated protein C (APC), an important natural anticoagulant, inhibits tumor necrosis factor-α (TNF-α) production and attenuates various deleterious events induced by lipopolysaccharide (LPS), contributing thereby to a significant reduction of mortality in patients with severe sepsis. In this study, we investigated the mechanism(s) by which APC inhibits TNF-α production by LPS-stimulated human monocytes in vitro. Although APC inhibited LPS-induced TNF-α production in a concentration-dependent fashion, diisopropyl fluorophosphate-treated APC, an active-site-blocked APC, had no effect. APC inhibited both the binding of nuclear factor-κB (NF-κB) to target sites and the degradation of IκBα. APC 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 APC inhibited LPS-induced TNF-α production by inhibiting the activation of both NF-κB and AP-1 and that the inhibitory activity of APC might depend on its serine protease activity. These results would at least partly explain the mechanism(s) by which APC reduces the tissue injury seen in animal models of sepsis and in patients with sepsis.

Neuroprotection by Recombinant Thrombomodulin

We examined whether recombinant human soluble thrombomodulin (rhs-TM) reduces compression trauma-induced spinal cord injury through protein C activation in rats. Administration of rhs-TM, either before or after the induction of spinal cord injury (SCI), markedly reduced the resulting motor disturbances. However, neither rhs-TM pretreated with an anti-rhs-TM monoclonal antibody (MAb) F2H5, which inhibits thrombin binding to rhs-TM, nor those pretreated with MAb R5G12, which selectively inhibits protein C activation by rhsTM, prevented the motor disturbances. Intramedullary hemorrhages, observed 24 h after trauma, were significantly reduced in animals given rhs-TM. The increase in the tissue levels of tumor necrosis factor-α (TNF-α), TNF-α mRNA expression, and the accumulation of leukocytes in the damaged segment of the spinal cord were significantly inhibited in animals receiving rhs-TM, but these effects were not observed following administration of rhs-TM pretreated with MAb R5G12 or MAb F2H5. Leukocytopenia and activated protein C all produced effects similar to those of rhs-TM.

These findings suggest that rhs-TM prevents compression traumainduced SCI by inhibiting leukocyte accumulation by reducing the expression of TNF-α mRNA and such therapeutic effects of rhs-TM could be dependent on its protein C activation capacity. Findings further suggest that thrombomodulin can be implicated not only in the coagulation system but in regulation of the inflammatory response.

Recombinant Tissue Factor Pathway Inhibitor Prevents Lipopolysaccharide-induced Systemic Hypotension in Rats by Inhibiting Excessive Production of Nitric Oxide

Excessive production of nitric oxide (NO) by the inducible form of NO synthase (iNOS) plays a key role in the development of endotoxin shock. Tumor necrosis factor-α (TNF-α) induces iNOS, thereby contributing to the development of shock. We recently reported that recombinant tissue factor pathway inhibitor (r-TFPI), an important inhibitor of the extrinsic pathway of the coagulation system, inhibits TNF-α production by monocytes. In this study, we investigated whether r-TFPI could ameliorate hypotension by inhibiting excessive production of NO in rats given lipopolysaccharide (LPS). Pretreatment of animals with r-TFPI prevented LPS-induced hypotension. Recombinant TFPI significantly inhibited the increases in both the plasma levels of NO2 -/NO3 - and lung iNOS activity 3 h after LPS administration. Expression of iNOS mRNA in the lung was also inhibited by intravenous administration of r-TFPI. However, neither DX-9065a, a selective inhibitor of factor Xa, nor an inactive derivative of factor VIIa (DEGR-F.VIIa) that selectively inhibits factor VIIa activity, had any effect on LPS-induced hypotension despite their potent anticoagulant effects. Moreover, neither the plasma levels of NO2 -/NO3 - nor lung iNOS activity were affected by administration of DX-9065a and DEGR-F.VIIa. These results suggested that r-TFPI ameliorates LPS-induced hypotension by reducing excessive production of NO in rats given LPS and this effect was not attributable to its anticoagulant effects, but to the inhibition of TNF-α production.

Role of Microthrombus Formation in the Development of Ischemia/Reperfusion-induced Liver Injury in Rats

Although tumor necrosis factor-α (TNF-α) has been shown to play a critical role in the pathologic process leading to ischemia/reperfusion (I/R)-induced liver injury in rats by activating neutrophils, it is not clear whether or not microthrombus formation induced by TNF-α contributes to the liver injury. In the present study, we investigated the role of microthrombus formation in I/R-induced liver injury in rats. Hepatic tissue levels of TNF-α were significantly increased after reperfusion, and these were higher in animals subjected to 120 min-hepatic I/R than in those subjected to 60 min-hepatic I/R. Fibrin deposition was observed histologically in the hepatic sinusoidal space only in animals subjected to 120 min-hepatic I/R. Both the decrease in hepatic tissue blood flow and the extent of liver injury in animals subjected to 60 minand 120 min-hepatic I/R were significantly inhibited by pretreatment with anti-rat TNF-α antibody. Although neutrophil elastase inhibitors inhibited the decrease in hepatic tissue blood flow and reduced liver injury in animals subjected to 60 min-hepatic I/R, anticoagulants did not show any effects. Both anticoagulants and neutrophil elastase inhibitors inhibited the decrease in hepatic tissue blood flow and reduced liver injury in animals subjected to 120 min-hepatic I/R. Therapeutic effects of anti-rat TNF-α antibody on the120 min-I/R-induced liver injury were more marked than those of each anticoagulant or each neutrophil elastase inhibitor, and were comparable to those of combined use of anticoagulants and neutrophil elastase inhibitors. These observations strongly suggest that TNF-α induces I/R-induced liver injury primarily by activating neutrophils, and it exacerbates liver injury by inducing microthrombus formation when the production of TNF-α is further increased.

Inhibition of lipopolysaccharide-induced tissue factor expression in monocytes by urinary trypsin inhibitor in vitro and in vivo

Tissue factor (TF) plays a critical role in the pathogenesis of disseminated intravascular coagulation (DIC) observed in patients with septic shock. Urinary trypsin inhibitor (UTI), a multivalent protease inhibitor, is currently used for treatment of patients with septic shock. This study was undertaken to determine whether UTI reduces LPS-induced coagulation abnormalities by inhibiting lipopolysaccharide (LPS)-induced expression of TF by monocytes. UTI inhibited LPS-induced increases in both TF activities andTF mRNA expression in monocytes without affecting the viability. Although activation of nuclear factor-κB (NF-κB), activator protein-1 (AP-1) and extracellular signal-regulated kinase (ERK)1/2 were shown to be critically involved in LPS-induced increases in TF activities in isolated monocytes, UTI inhibited phosphorylation of ERK1/2 and decreased expression of early growth response factor-1 (Egr-1) induced by LPS without affecting the activation of NF-κB and AP-1. UTI inhibited both the expression of TF mRNA in whole blood, increases in TF activities in mononuclear cells, and increases in serum levels of fibrin and fibrinogen degradation products (E) in rats given LPS without affecting the number of monocytes in the peripheral blood. Taken together these results strongly suggested that UTI might reduce LPS-induced coagulation abnormalities in rats by inhibiting TF expression in monocytes through inhibition of Egr-1 expression.

Antithrombin reduces reperfusion-induced liver injury in mice by enhancing sensory neuron activation

We recently demonstrated that antithrombin (AT) reduces ischemia/reperfusion (I/R)-induced liver injury in rats by increasing hepatic tissue levels of calcitonin gene-related peptide (CGRP),a neuropeptide released from the sensory nerve endings. In the present study, we examined the effect of AT on I/Rinduced liver injury in wild type mice (CGRP+/+) and congenitally αCGRP-deficient mice (CGRP−/−). We also investigated any effects of AT on CGRP release from dorsal root ganglion neurons (DRG) isolated from CGRP+/+. Based on results obtained in the present study, we attempted to determine if the anti-inflammatory activity of AT in vivo is dependent mainly on sensory neuron activation. AT enhanced ischemia/reperfusion-induced increases in hepatic tissue levels of CGRP and 6-keto-PGF1α , a stable metabolite of PGI2, in CGRP+/+, but it did not enhance these increases in CGRP−/−. AT inhibited reperfusion-induced increases in serum alanine aminotransferase levels by increasing hepatic tissue blood flow and by attenuating increases in hepatic levels of tumor necrosis factor and myeloperoxidase in CGRP+/+,although it showed neither of these therapeutic effects in CGRP−/−. AT increased CGRP release from cultured DRGs only in the presence of anandamide, and AT-induced increase in CGRP release was not observed in the presence KT5720, an inhibitor of protein kinase A (PKA).AT markedly increased intracellular levels of cAMP in the presence of anandamide. These results strongly suggest that AT might reduce I/R-induced liver injury by enhancing activation of the sensory neurons through activation of PKA in sensory neurons.

Antithrombin reduces ischemia/reperfusion-induced liver injury in rats by activation of cyclooxygenase-1

This study was conducted to determine which isoform of cyclooxygenase (COX) is more significantly involved in the antithrombin (AT)-induced increase in prostaglandin production in the liver of rats, subjected to hepatic ischemia/reperfusion (I/R). Hepatic tissue levels of 6-keto-PGF1α, a stable metabolite of prostacyclin (PGI2), and PGE2 were transiently increased 1 hour after reperfusion. Thereafter, hepatic PGE2 levels were gradually increased until 6 hours after reperfusion, while hepatic 6-keto-PGF1α levels were decreased to the pre-ischemia levels at 6 hours after reperfusion. AT significantly enhanced increases in hepatic tissue levels of 6-keto-PGF1α and PGE2 seen 1 hour after reperfusion, while it inhibited increases in hepatic PGE2 levels seen 6 h after reperfusion. Neither dansyl-Glu-Gly-Arg-chloromethyl ketone-treated factor Xa (DEGR-Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT which lacks affinity for heparin, showed any effects on these changes. Pretreatment with indomethacin (IM), a non-selective inhibitor of COX, inhibited AT-induced increases in hepatic tissue levels of 6-keto-PGF1α and PGE2 seen 1 hour after reperfusion, whereas pretreatment with NS-398, a selective inhibitor of COX-2, did not. The increase in hepatic tissue blood flow and inhibition of hepatic inflammatory responses seen in animals given AT were reversed by pretreatment with IM, but were not affected by pretreatment with NS-398. Administration of iloprost, a stable analog of PGI2, and PGE2 produced effects similar to those induced by AT. Increases in hepatic tissue levels of PGE2 6 hours after reperfusion were inhibited by pretreatment with NS-398. Although AT did not affect COX-1 mRNA levels 1 hour after reperfusion, it inhibited the I/R-induced increases in hepatic tissue levels of both PGE2 and COX-2 mRNA 6 hours after reperfusion. These observations strongly suggested that AT might reduce the I/R-induced liver injury by increasing the production of PGI2 and PGE2 through activation of COX-1. Furthermore, since TNF-a is capable of inducing COX-2, inhibition of TNF-a production by AT might inhibit COX-2-mediated PGE2 production. These effects induced by AT might contribute to its anti-inflammatory activity.

Danaparoid sodium reduces ischemia/reperfusion-induced liver injury in rats by attenuating inflammatory responses

This study was undertaken to examine the mechanism by which danaparoid sodium (DS), a heparinoid that contains mainly heparan sulfate, prevents reperfusion-induced hepatic damage in a rat model of ischemia/reperfusion (I/R)-induced liver injury. Administration of DS significantly reduced liver injury and inhibited the decrease in hepatic tissue blood flow in rats. DS attenuated hepatic I/R-induced increases in hepatic tissue levels of tumor necrosis factor (TNF) and myeloperoxidase (MPO) in vivo. In contrast, neither monocytic TNF production nor neutrophil activation was inhibited by DS in vitro. DS enhanced I/R-induced increases in levels of calcitonin-gene related peptide (CGRP), a neuropeptide released from sensory neurons, and of 6-ketoprostaglandin (PG) F1α, a stable metabolite of PGI2, in liver tissues. The therapeutic effects of DS were not seen in animals pretreated with capsazepine, an inhibitor of sensory neuron activation. The distribution of heparan sulfate in the perivascular area was significantly increased by DS administration in this rat model. DS significantly increased CGRP release from isolated rat dorsal root ganglion neurons (DRG) in vitro, while DX-9065a, a selective inhibitor of activated factor X, did not. DS enhanced anandamide-induced CGRP release from DRG in vitro. These observations strongly suggested that DS might reduce I/R-induced liver injury in rats by attenuating inflammatory responses. These therapeutic effects of DS might be at least partly explained by its enhancement of sensory neuron activation, leading to the increase the endothelial production of PGI2.

Acquired factor V deficiency following transcatheter arterial chemoembolization for hepatocellular carcinoma: a case report

Acquired factor V deficiency is a rare condition associated with a wide variety of causes. We herein report the case of a 75-year-old man who developed acquired factor V deficiency associated with gastrointestinal bleeding after transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma. Laboratory data revealed prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) and a significant reduction in the factor V (FV) activity. Infusion of fresh-frozen plasma (FFP) was unable to correct the prolonged PT and APTT. Four weeks after onset, his coagulation parameters improved spontaneously with no particular treatment. The patient developed acquired FV deficiency after TACE treatment using cisplatin, and thus, cisplatin was suspected as the cause of this coagulopathy. If coagulopathy that is not corrected by FFP transfusion after TACE is observed, acquired factor V deficiency, although extremely rare, should be considered.

A case of pulmonary thromboembolism due to coagulation factor V Leiden in Japan ~ usefulness of next generation sequencing~

Background

Because the venous thromboembolisms (VTEs) due to the coagulation factor V R506Q (FV Leiden) mutation is often seen in Caucasians, the VTE onset in Japan has not been reported.

Case presentation

A 34-year-old man from north Africa experiencing sudden dyspnea went to a hospital for advice.

The patient had pain in his right leg and a high plasma D-dimer level. A contrast-enhanced computed tomography scan revealed a contrast deficit in the bilateral pulmonary artery and in the right lower extremity. The patient was diagnosed with VTE, and anticoagulation therapy was initiated. Our targeted gene panel sequencing revealed that the occurrence of VTE was attributed to a presence of the FV Leiden mutation.

Conclusions

This is the first report demonstrating VTE caused by the FV Leiden mutation in Japan.

Metformin, an antidiabetic agent, suppresses the production of tumor necrosis factor and tissue factor by inhibiting early growth response factor-1 expression in human monocytes in vitro

Metformin, an antidiabetic agent, has been shown to reduce atherothrombotic disease in diabetic patients independent of antihyperglycemic effect. Recent studies have demonstrated that metformin attenuates the proinflammatory responses in human vascular wall cells and macrophages. However, the detailed molecular mechanisms underlying these therapeutic effects remain unclear. In the present study, we investigated the effects of metformin on tumor necrosis factor (TNF) production and tissue factor (TF) expression in isolated human monocytes stimulated with lipopolysaccharide (LPS) or oxidized low-density lipoprotein (oxLDL). Metformin significantly inhibited both TNF production and TF expression in isolated human monocytes stimulated with LPS or oxLDL. Metformin also significantly inhibited TNF and TF mRNA in human monocytes stimulated with LPS. Although metformin did not inhibit the activation of either nuclear factor-kappaB or activator protein-1, it inhibited the expression of early growth response factor-1 (Egr-1) and phosphorylation of extracellular signal-regulated protein kinase (ERK) 1/2 in monocytes stimulated with LPS or oxLDL. These results suggest that metformin may attenuate the inflammatory responses, at least in part, by suppressing the production of both TNF and TF through the inhibition of the ERK1/2-Egr-1 pathway in human monocytes.

[Mixing test for prolonged clotting time: clinical availability and problems]

Prothrombin time (PT) and activated partial thromboplastin time (APTT) are basic laboratory tests for diagnosis of bleeding diseases such as congenital hemophilia. In addition, abnormally prolonged clotting times are observed in patients who have inhibitors. Lupus anticoagulant and inhibitors against coagulation factors are two clinically important inhibitors. However, non-specific inhibitors are also observed. Differential diagnosis of these inhibitors is important. Clotting times are also prolonged by artifactitious factors, such as contamination of heparin. Mixing tests are relatively easy and useful methods which potentially differentiate these abnormalities. This article is summarized the causes of prolongation of clotting times and the usefulness of mixing tests for differentiation of the abnormalities.

Excessive fibrinolysis in AL-amyloidosis is induced by urokinae-type plasminogen activator from bone marrow plasma cells

Activation of fibrinolysis system and excessive fibrinolysis are observed in monoclonal antibody light chain (AL)-amyloidosis. However, the mechanisms by which activation of fibrinolysis occurs in AL-amyloidosis have not been fully elucidated. To determine whether urokinase type-plasminogen activator (uPA), an important activator of fibrinolytic system, contributes to the activation of fibrinolytic system in AL-amyloidosis, we immunohistologically examined uPA in bone marrow plasma cells. More than 90% of bone marrow plasma cells from five different AL-amyloidosis patients were uPA-positive as examined with immunohistochemical staining. All the bone marrow plasma cells from seven different patients with multiple myeloma were uPA-negative. A patient with AL-amyloidosis, who had bleeding diathesis and excessive fibrinolysis with hypofibrinogenemia, was treated with nafamostat mesilate, a potential inhibitor of uPA. After the administration of nafamostat mesilate, the bleeding diathesis disappeared, and excessive fibrinolysis and hypofibrinogenemia were improved. The present data suggested that uPA expressed in plasma cells may have contributed to the pathogenesis of excessive fibrinolysis.

Antithrombin inhibits lipopolysaccharide-induced tumor necrosis factor-alpha production by monocytes in vitro through inhibition of Egr-1 expression

BACKGROUND

Antithrombin (AT) improves the outcome of septic patients with intravascular coagulation. However, the mechanisms underlying the therapeutic benefits of AT are not fully understood. Tumor necrosis factor-alpha (TNF-alpha) plays a critical role in the development of organ failure and intravascular coagulation in sepsis.

AIM

This study aimed to elucidate a molecular mechanism by which AT inhibits TNF-alpha production.

METHODS

Human peripheral monocyte was stimulated by lipopolysaccharide (LPS) and TNF-alpha concentration in media was measured. Levels of phosphorylation of extracellular signal-regulated protein kinases (ERK) 1/2 and early growth response factor-1 (Egr-1) were estimated by western blotting or by electrophoretic mobility shift assay.

RESULTS

Antithrombin (3 U mL(-1)) inhibited TNF-alpha production by monocytes stimulated with LPS. Conversely, chemically modified AT that lacks affinity for heparin did not. AT inhibited the phosphorylation of ERK 1/2 and decreased the expression of Egr-1 in LPS-stimulated monocytes. However, it did not affect the activation of either nuclear factor-kappaB or activator protein-1. Pretreatment with KT5720, a protein kinase A inhibitor, reversed the inhibitory effect of AT on the LPS-induced phosphorylation of ERK1/2. Although 2 U mL(-1) AT slightly inhibited TNF-alpha production by LPS-stimulated monocytes, it significantly inhibited TNF-alpha production in the presence of a low concentration of beraprost, a stable derivative of prostacyclin.

CONCLUSIONS

These observations suggest that AT might inhibit LPS-induced production of TNF-alpha by inhibiting the increase in Egr-1 expression in monocytes via interaction with heparin-like substances expressed on the cell surface.

Carvedilol, a nonselective beta-blocker, suppresses the production of tumor necrosis factor and tissue factor by inhibiting early growth response factor-1 expression in human monocytes in vitro

Tumor necrosis factor (TNF) and tissue factor (TF) produced by monocytes and macrophages have been shown to be among the aggravating factors for chronic heart failure (CHF), because they induce cardiac dysfunction and thrombotic complications, respectively. Carvedilol, a nonselective beta-adrenoceptor antagonist with alpha(1)- adrenoceptor blockade action, has been demonstrated to improve the outcome of patients with severe CHF, suggesting that carvedilol might inhibit the production of TNF and TF. In this study, this possibility is examined using isolated human monocytes stimulated with lipopolysaccharide (LPS) in vitro. Carvedilol (10 muM) significantly inhibited LPS-induced production of TNF and TF by monocytes, whereas prazosin (a selective alpha(1)-adrenoceptor antagonist), bisoprolol (a selective beta(1)-adrenoceptor antagonist), ICI-118,551 (a selective beta(2)-adrenoceptor antagonist), and arotinolol (a nonselective beta-adrenoceptor antagonist with alpha(1)-adrenoceptor blockade action) did not. Carvedilol inhibited both expression of early growth response factor-1 (Egr-1) and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, but it did not inhibit activation of either nuclear factor-kappaB or activator protein-1 in monocytes stimulated with LPS. These results suggest that carvedilol inhibits LPS-induced production of TNF and TF by inhibiting activation of the ERK1/2-Egr-1 pathway independent of its adrenoceptor inhibitory activities in monocytes.

Danaparoid sodium reduces ischemia/reperfusion-induced liver injury in rats by attenuating inflammatory responses

This study was undertaken to examine the mechanism by which danaparoid sodium (DS), a heparinoid that contains mainly heparan sulfate, prevents reperfusion-induced hepatic damage in a rat model of ischemia/reperfusion (I/R)-induced liver injury. Administration of DS significantly reduced liver injury and inhibited the decrease in hepatic tissue blood flow in rats. DS attenuated hepatic I/R-induced increases in hepatic tissue levels of tumor necrosis factor (TNF) and myeloperoxidase (MPO) in vivo. In contrast, neither monocytic TNF production nor neutrophil activation was inhibited by DS in vitro. DS enhanced I/R-induced increases in levels of calcitonin-gene related peptide (CGRP), a neuropeptide released from sensory neurons, and of 6-ketoprostaglandin (PG) F (1a) , a stable metabolite of PGI (2) , in liver tissues. The therapeutic effects of DS were not seen in animals pretreated with capsazepine, an inhibitor of sensory neuron activation. The distribution of heparan sulfate in the perivascular area was significantly increased by DS administration in this rat model. DS significantly increased CGRP release from isolated rat dorsal root ganglion neurons (DRG) in vitro, while DX-9065a, a selective inhibitor of activated factor X, did not. DS enhanced anandamide-induced CGRP release from DRG in vitro. These observations strongly suggested that DS might reduce I/R-induced liver injury in rats by attenuating inflammatory responses. These therapeutic effects of DS might be at least partly explained by its enhancement of sensory neuron activation, leading to the increase the endothelial production of PGI (2) .

Antithrombin reduces endotoxin-induced hypotension by enhancing pulmonary sensory neuron activation in rats

We recently demonstrated that activation of the pulmonary sensory neurons plays a critical role in prevention of endotoxin-induced shock by releasing calcitonin gene-related peptide (CGRP) in rats. CGRP increased the endothelial production of prostacyclin (PGI(2)) in the lungs, thereby preventing endotoxin-induced shock response by inhibiting tumor necrosis factor-alpha (TNF-alpha) production. Since antithrombin (AT) enhances sensory neuron activation, we hypothesized that AT might reduce endotoxin-induced hypotension by enhancing the activation of pulmonary sensory neurons in rats. We examined this possibility using a rat model of endotoxin shock. AT-induced effects including reduction of hypotension (n = 5) and inhibition of induction of iNOS (n = 4 or 5) and TNF- alpha (n = 5) in the lungs of endotoxin-treated animals were completely reversed by pretreatment with capsazepine (CPZ) (n = 4 or 5), a vanilloid receptor antagonist, or CGRP(8-37), a CGRP receptor antagonist (n = 4 or 5). AT enhanced endotoxin-induced increases in lung tissue levels of CGRP (n = 4), but this effect of AT was not seen in animals pretreated with CPZ (n = 4). CGRP produced therapeutic effects (n = 5) similar to those induced by AT, and such therapeutic effects were completely abrogated by pretreatment with indomethacin (n = 4). AT increased CGRP release from cultured dorsal root ganglion neurons only in the presence of anandamide (n = 5), and AT-induced increase in CGRP release was not observed in the presence KT5720, an inhibitor of protein kinase A (n = 5). AT markedly increased intracellular levels of cAMP in the presence of anandamide (n = 5). These results strongly suggested that AT might reduce endotoxin-induced hypotension in rats by enhancing activation of sensory neurons via activation of protein kinase A.

Dalteparin, a low molecular weight heparin, attenuates inflammatory responses and reduces ischemia-reperfusion-induced liver injury in rats

OBJECTIVE

To examine whether dalteparin, a low molecular weight heparin, prevents hepatic damage by inhibiting leukocyte activation, we analyzed its effect on ischemia/reperfusion (I/R) 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 220-280 g.

INTERVENTIONS

Hepatic damage was evaluated by changes in serum transaminase concentrations after I/R. Coagulation abnormalities were evaluated by changes in serum concentrations of fragment E of fibrin and fibrinogen degradation products after I/R. Hepatic tissue blood flow was measured by laser-Doppler flow meter. Hepatic edema was evaluated by determination of the change in the wet/dry tissue weight ratio. Rats were intravenously injected with dalteparin or unfractionated heparin (300 units/kg) and subcutaneously injected with DX9056a, a selective inhibitor of activated factor X (3 mg/kg). To determine whether dalteparin inhibits leukocyte activation, we examined the effect of dalteparin on hepatic concentrations of interleukin-12, tumor necrosis factor-alpha, and hepatic myeloperoxidase activity after I/R in vivo. In addition, we examined increases in tumor necrosis factor-alpha production in rat monocytes and in intracellular calcium concentrations in neutrophils in vitro. We also examined the effect of dalteparin on endothelial production of prostacyclin using isolated rat hepatic sinusoidal cells in vitro.

MEASUREMENTS AND MAIN RESULTS

Intravenous administration of dalteparin inhibited increases in serum levels of both transaminases and serum concentrations of fragment E of fibrin and fibrinogen degradation products in animals subjected to hepatic I/R. Hepatic tissue blood flow after reperfusion was increased by dalteparin. Dalteparin inhibited hepatic edema, increases in hepatic tissue levels of interleukin-12 and tumor necrosis factor-alpha, and accumulation of neutrophils in animals subjected to hepatic I/R. Neither DX9065a nor unfractionated heparin showed any therapeutic effects, despite potent inhibition of increases in serum levels of fragment E of fibrin and fibrinogen degradation products. Neither monocytic tumor necrosis factor-alpha production nor neutrophil activation was inhibited by dalteparin in vitro. Dalteparin enhanced the hepatic I/R-induced increases in hepatic tissue levels of 6-keto-prostaglandin (PG) F1alpha, a stable metabolite of prostacyclin, which is capable of inhibiting monocytic tumor necrosis factor-alpha production. Pretreatment with indomethacin completely reversed both of the therapeutic effects of dalteparin, whereas pretreatment with NS-398, a selective inhibitor of cyclooxygenase-2, did not. Dalteparin did not directly increase the endothelial production of prostacyclin in vitro.

CONCLUSION

Dalteparin might reduce I/R-induced liver injury in rats by attenuating inflammatory responses. These therapeutic effects might be independent of its anticoagulant activity but dependent on its capacity to enhance endothelial production of prostacyclin via cyclooxygenase-1 activation. Furthermore, the mechanism or mechanisms by which dalteparin promotes the endothelial production of prostacyclin in vivo might involve unknown factors other than endothelial cells.

Antithrombin reduces reperfusion-induced liver injury in mice by enhancing sensory neuron activation

We recently demonstrated that antithrombin (AT) reduces ischemia/reperfusion (I/R)-induced liver injury in rats by increasing hepatic tissue levels of calcitonin gene-related peptide (CGRP), a neuropeptide released from the sensory nerve endings. In the present study, we examined the effect of AT on I/R-induced liver injury in wild type mice (CGRP+/+) and congenitally alphaCGRP-deficient mice (CGRP-/-). We also investigated any effects of AT on CGRP release from dorsal root ganglion neurons (DRG) isolated from CGRP+/+. Based on results obtained in the present study, we attempted to determine if the anti-inflammatory activity of AT in vivo is dependent mainly on sensory neuron activation. AT enhanced ischemia/reperfusion-induced increases in hepatic tissue levels of CGRP and 6-keto-PGF(1alpha), a stable metabolite of PGI2, in CGRP+/+, but it did not enhance these increases in CGRP-/-. AT inhibited reperfusion-induced increases in serum alanine aminotransferase levels by increasing hepatic tissue blood flow and by attenuating increases in hepatic levels of tumor necrosis factor and myeloperoxidase in CGRP+/+, although it showed neither of these therapeutic effects in CGRP-/-. AT increased CGRP release from cultured DRGs only in the presence of anandamide, and AT-induced increase in CGRP release was not observed in the presence KT5720, an inhibitor of protein kinase A (PKA). AT markedly increased intracellular levels of cAMP in the presence of anandamide. These results strongly suggest that AT might reduce I/R-induced liver injury by enhancing activation of the sensory neurons through activation of PKA in sensory neurons.

Antithrombin reduces reperfusion-induced hepatic metastasis of colon cancer cells

AIM: To examine whether antithrombin (AT) could prevent hepatic ischemia/reperfusion (I/R)-induced hepatic metastasis by inhibiting tumor necrosis factor (TNF)-α-induced expression of E-selectin in rats.

METHODS: Hepatic I/R was induced in rats and mice by clamping the left branches of the portal vein and the hepatic artery. Cancer cells were injected intrasplenically. The number of metastatic nodules was counted on day 7 after I/R. TNF-α and E-selectin mRNA in hepatic tissue, serum fibrinogen degradation products and hepatic tissue levels of 6-keto-PGF_1α, a stable metabolite of PGI₂, were measured.

RESULTS: AT inhibited increases in hepatic metastasis of tumor cells and hepatic tissue mRNA levels of TNF-α and E-selectin in animals subjected to hepatic I/R. Argatroban, a thrombin inhibitor, did not suppress any of these changes. Both AT and argatroban inhibited I/R-induced coagulation abnormalities. I/R-induced increases of hepatic tissue levels of 6-keto-PGF_1α were significantly enhanced by AT. Pretreatment with indomethacin completely reversed the effects of AT. Administration of OP-2507, a stable PGI₂ analog, showed effects similar to those of AT in this model. Hepatic metastasis in congenital AT-deficient mice subjected to hepatic I/R was significantly increased compared to that observed in wild-type mice. Administration of AT significantly reduced the number of hepatic metastases in congenital AT-deficient mice.

CONCLUSION: AT might reduce I/R-induced hepatic metastasis of colon cancer cells by inhibiting TNF-α-induced expression of E-selectin through an increase in the endothelial production of PGI₂. These findings also raise the possibility that AT might prevent hepatic metastasis of tumor cells if administered during the resection of liver tumors.

Inhibition of the endothelial cell activation by antithrombin in vitro

We examined whether antithrombin (AT) inhibits tumor necrosis factor (TNF)-alpha-induced endothelial cell activation to elucidate molecular mechanism(s) of the anti-inflammatory activity of AT. AT inhibited the increase in E-selectin expression in cultured human umbilical vein endothelial cells (HUVECs) stimulated with TNF-alpha. In contrast, chemically modified AT that lacks affinity for heparin did not. AT inhibited the TNF-alpha-induced interaction of NF-kappaB p65 with p300, a homologue of cAMP-responsive element binding protein (CREB)-binding protein (CBP). AT increased both intracellular levels of cAMP and binding of phosphorylated-CREB to DNA in HUVECs. Forskolin showed the inhibitory effect similar to that of AT and pretreatment of HUVECs with KT-5720, an inhibitor of protein kinase A, reversed the inhibitory effect of AT. These observations suggested that AT inhibited the TNF-alpha-induced increase in E-selectin expression in HUVECs by inhibiting the interaction of NF-kappaB with CBP/p300 through cAMP-dependent protein kinase A-induced CREB activation. This inhibitory activity of AT might depend on its binding to heparin-like substances on the endothelial cell. Such an inhibitory effect of AT on TNF-alpha-induced endothelial cell activation might at least partly contribute to its anti-inflammatory activity.

Role of sensory neuron in reduction of endotoxin-induced hypotension in rats

OBJECTIVE

We attempted to determine whether activation of the sensory neuron contributes to reduction of endotoxin-induced hypotension by inhibiting tumor necrosis factor (TNF)-alpha production via calcitonin gene-related peptide (CGRP) release in rats.

DESIGN

Prospective, randomized, controlled study.

SETTING

Research laboratory at a university medical center.

SUBJECTS

Wistar rats weighing 220-280 g.

INTERVENTIONS

Mean arterial blood pressure was measured in rats administered endotoxin intravenously. Animals were pretreated with capsazepine (a vanilloid receptor antagonist), CGRP(8-37) (a CGRP receptor antagonist), and indomethacin before endotoxin administration. Levels of CGRP, 6-keto-prostaglandin F1alpha, TNF-alpha, and cytokine-induced neutrophil chemoattractant (CINC) were measured by enzyme immunoassay methods. The concentration of NO2/NO3 was measured using the Griess reagent. Tissue levels of messenger RNA of the inducible form of nitric oxide synthase (iNOS) and TNF-alpha were determined by reverse transcription polymerase chain reaction.

MEASUREMENTS AND MAIN RESULTS

Both lung levels of CGRP and plasma levels of 6-keto-prostaglandin F1alpha were increased after intravenous administration of endotoxin (5 mg/kg), peaking at 90 mins after endotoxin administration. Increases in plasma levels of 6-keto-prostaglandin F1alpha at 90 mins after endotoxin administration (766 +/- 134 pg/mL) were inhibited by pretreatment with capsazepine (373 +/- 44 pg/mL, p < .05), CGRP(8-37) (406 +/- 64 pg/mL, p < .05), and indomethacin (154 +/- 40 pg/mL, p < .05). Although none of the pretreatments affected a series of endotoxin-induced responses, including increases in lung tissue levels of TNF-alpha, CINC, and iNOS and the resultant hypotension in animals given 5 mg/kg endotoxin, such pretreatments enhanced these pathologic responses in animals given a smaller dose of endotoxin (1 mg/kg) to the same extent as those induced by 5 mg/kg of endotoxin, suggesting that shock responses induced by 5 mg/kg endotoxin are maximum responses and activation of sensory neurons in endotoxin-treated rats is essentially a reparative response.

CONCLUSION

Activation of sensory neurons might contribute to reduction of endotoxin-induced hypotension by releasing CGRP, which is capable of promoting endothelial production of prostacyclin.

Neutrophil elastase contributes to the development of ischemia-reperfusion-induced liver injury by decreasing endothelial production of prostacyclin in rats

We previously reported that nitric oxide (NO) derived from endothelial NO synthase (NOS) increased endothelial prostacyclin (PGI(2)) production in rats subjected to hepatic ischemia-reperfusion (I/R). The present study was undertaken to determine whether neutrophil elastase (NE) decreases endothelial production of PGI(2), thereby contributing to the development of I/R-induced liver injury by decreasing hepatic tissue blood flow in rats. Hepatic tissue levels of 6-keto-PGF(1alpha), a stable metabolite of PGI(2), were transiently increased and peaked at 1 h after reperfusion, followed by a gradual decrease until 3 h after reperfusion. Sivelestat sodium hydrochloride and L-658,758, two NE inhibitors, reduced I/R-induced liver injury. These substances inhibited the decreases in hepatic tissue levels of 6-keto-PGF(1alpha) at 2 and 3 h after reperfusion but did not affect the levels at 1 h after reperfusion. These NE inhibitors significantly increased hepatic tissue blood flow from 1 to 3 h after reperfusion. Both hepatic I/R-induced increases in the accumulation of neutrophils and the microvascular permeability were inhibited by these two NE inhibitors. Protective effects induced by the two NE inhibitors were completely reversed by pretreatment with nitro-l-arginine methyl ester, an inhibitor of NOS, or indomethacin. Administration of iloprost, a stable derivative of PGI(2), produced effects similar to those induced by NE inhibitors. These observations strongly suggest that NE might play a critical role in the development of I/R-induced liver injury by decreasing endothelial production of NO and PGI(2), leading to a decrease in hepatic tissue blood flow resulting from inhibition of vasodilation and induction of activated neutrophil-induced microvascular injury.

Antithrombin Reduces Compression-Induced Spinal Cord Injury in Rats

Antithrombin (AT), a natural anticoagulant, has been shown to exert anti-inflammatory activity by promoting the endothelial production of prostaglandin I2 (PGI2), thereby reducing tissue injury. To examine whether AT prevents post-traumatic spinal cord injury (SCI), a pathologic condition in which activated neutrophils are critically involved, we tested the effect of AT on SCI induced by compression trauma in rats. Intravenous administration of AT, either before or after the induction of SCI, significantly reduced SCI-related motor disturbances in these animals. AT also significantly inhibited both intramedullary hemorrhage and the decrease in the number of motor neurons following SCI, and inhibited the accumulation of neutrophils in the damaged segment of the spinal cord by inhibiting the increase in transcription of tumor necrosis factor-alpha (TNF-alpha). AT significantly enhanced the increase in the tissue level of 6-keto-PGF1alpha, a stable metabolite of PGI2, at the injured segment of the cord. These therapeutic effects of AT may not depend on its anticoagulant effect. AT did not show any effects in animals pretreated with indomethacin, a potent inhibitor of prostaglandin synthesis, and iloprost, a stable PGI2 analog, produced effects similar to those of AT. Furthermore, intravenously administered AT accumulated selectively at the injured segment of the spinal cord, where thrombin generation might be increased. These findings suggest that AT may reduce the effects of compression trauma-induced SCI by inhibiting neutrophil activation as a consequence of the AT-mediated inhibition of TNF-alpha production. Such therapeutic effects of AT might be mediated by its promoting the endothelial release of PGI2. These findings strongly suggest AT as a potential agent for treating SCI in the clinical setting.

Urinary trypsin inhibitor reduces LPS-induced hypotension by suppressing tumor necrosis factor-alpha production through inhibition of Egr-1 expression

Although urinary trypsin inhibitor (UTI) has been shown to inhibit tumor necrosis factor (TNF)-alpha- production, the detailed mechanism(s) remains unclear. This study was undertaken to elucidate the molecular mechanism(s) underlying this inhibitory effect in monocytes in vitro and in rats given lipopolysaccharide (LPS). TNF-alpha production by monocytes stimulated with LPS (100 ng/ml) was inhibited by UTI at concentrations higher than 100 U/ml. Expression of early growth response factor-1 (Egr-1) and phosphorylation of extracellular signal-regulated protein kinases 1/2 in monocytes stimulated with LPS were inhibited by UTI. UTI (50,000 U/kg i.v.) inhibited LPS (5 mg/kg i.v.)-induced increases in lung tissue levels of Egr-1, TNF-alpha mRNA, and TNF-alpha in rats. UTI inhibited LPS-induced hypotension by inhibiting pulmonary induction of inducible nitric oxide synthase (iNOS). We previously demonstrated that anti-TNF-alpha antibody and aminoguanidine, a selective inhibitor of iNOS, reduced LPS-induced hypotension in this animal model. Furthermore, we also reported that reduction of LPS-induced coagulation abnormalities in rats did not affect inflammatory responses and hypotension in this animal model. Taken together, these observations strongly suggested that UTI inhibited LPS-induced production of TNF-alpha by inhibiting activation of the extracellular signal-regulated protein kinases 1/2-Egr-1 pathway in monocytes, which might at least partly contribute to reduction of hypotension through inhibition of iNOS induction in rats given LPS.

Antithrombin reduces the ischemia/reperfusion-induced spinal cord injury in rats by attenuating inflammatory responses

Antithrombin (AT) reveals its antiinflammatory activity by promoting endothelial release of prostacyclin (PGI(2)) in vivo. Since neuroinflammation is critically involved in the development of ischemia/reperfusion (I/R)-induced spinal cord injury (SCI), it is possible that AT reduces the I/R-induced SCI by attenuating the inflammatory responses. We examined this possibility using rat model of I/R-induced SCI in the present study. AT significantly reduced the mortality and motor disturbances by inhibiting reduction of the number of motor neurons in animals subjected to SCI. Microinfarctions of the spinal cord seen after reperfusion were markedly reduced by AT. AT significantly enhanced the I/R-induced increases in spinal cord tissue levels of 6-keto-PGFIalpha, a stable metabolite of PGI2. AT significantly inhibited the I/R-induced increases in spinal cord tissue levels of TNF-alpha, rat interleukin-8 and myeloperoxidase. In contrast,Trp(49) -modified AT did not show any protective effects. Pretreatment with indomethacin significantly reversed the protective effects of AT. An inactive derivative of factor Xa, which selectively inhibits thrombin generation, has been shown to fail to reduce SCI. Taken together, these observations strongly suggested that AT might reduce I/R-induced SCI mainly by the antiinflammatory effect through promotion of endothelial production of PGI(2). These findings also suggested that AT might be a potential neuroprotective agent.

Activated protein C induces endothelial cell proliferation by mitogen-activated protein kinase activation in vitro and angiogenesis in vivo

Activated protein C (APC), a natural anticoagulant, has recently been demonstrated to activate the mitogen-activated protein kinase (MAPK) pathway in endothelial cells in vitro. Because the MAPK pathway is implicated in endothelial cell proliferation, it is possible that APC induces endothelial cell proliferation, thereby causing angiogenesis. We examined this possibility in the present study. APC activated the MAPK pathway, increased DNA synthesis, and induced proliferation in cultured human umbilical vein endothelial cells dependent on its serine protease activity. Antibody against the endothelial protein C receptor (EPCR) inhibited these events. Early activation of the MAPK pathway was inhibited by an antibody against protease-activated receptor-1, whereas neither late and complete activation of the MAPK pathway nor endothelial cell proliferation were inhibited by this antibody. APC activated endothelial nitric oxide synthase (eNOS) via phosphatidylinositol 3-kinase-dependent phosphorylation, followed by activation of protein kinase G, suggesting that APC bound to EPCR might activate the endothelial MAPK pathway by a mechanism similar to that of VEGF. APC induced morphogenetic changes resembling tube-like structures of endothelial cells, whereas DIP-APC did not. When applied topically to the mouse cornea, APC clearly induced angiogenesis in wild-type mice, but not in eNOS knockout mice. These in vitro events induced by APC might at least partly explain the angiogenic activity in vivo. This angiogenic activity of APC might contribute to maintain proper microcirculation in addition to its antithrombotic activity.

Activation of Capsaicin-Sensitive Sensory Neurons by Carvedilol, a Nonselective β-Blocker, in Spontaneous Hypertensive Rats

We performed a study in spontaneous hypertensive rats (SHR) to determine whether carvedilol, a nonselective beta-adrenoceptor antagonist, activates capsaicin-sensitive sensory neurons (CSSNs), thereby promoting the release of calcitonin gene-related peptide (CGRP), a neuropeptide with an important role in maintenance of cardiovascular homeostasis. Carvedilol given intravenously at a dose of 0.3 mg/kg transiently decreased the mean arterial blood pressure (MABP) and increased renal tissue blood flow with increases in CGRP levels in plasma and kidney. These effects induced by carvedilol were not seen in animals pretreated with capsazepine, an antagonist of capsaicin. Although 1.0 mg/kg cavedilol markedly decreased MABP, it neither increased renal tissue blood flow nor CGRP levels in plasma and kidney. Prazosin, a selective alpha(1)-adrenoceptor antagonist, and bisoprolol, a selective beta(1)-adrenoceptor antagonist, decreased MABP with capsazepine, showing no antagonistic action in either cases, and these agents increased neither renal tissue blood flow nor levels of CGRP in plasma and kidney. Both ICI 118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol], a selective beta(2)-adrenoceptor antagonist, at a dose of 0.25 mg/kg and capsaicin mimicked effects induced by 0.3 mg/kg carvedilol. Administration of 1.0 mg/kg ICI 118,551 produced effects similar to those induced by 1.0 mg/kg carvedilol. These observations strongly suggested that the low dose of carvedilol might activate CSSNs in SHR to increase the release of CGRP, thereby decreasing blood pressure with an increase in renal tissue blood flow. The effects induced by carvedilol seemed to be mediated by its beta(2)-adrenoceptor blockade activity.

Contribution of capsaicin-sensitive sensory neurons to stress-induced increases in gastric tissue levels of prostaglandins in rats

We examined whether capsaicin-sensitive sensory neurons might be involved in the increase in the gastric tissue level of prostaglandins, thereby contributing to the reduction of water immersion restraint stress (WIR)-induced gastric mucosal injury in rats. Gastric tissue levels of calcitonin gene-related peptide (CGRP), 6-keto-PGF1alpha, and PGE2 were transiently increased 30 min after WIR. These increases were significantly inhibited by subcutaneous injection of capsazepine (CPZ), a vanilloid receptor antagonist, and by functional denervation of capsaicin-sensitive sensory neurons induced by the administration of high-dose capsaicin. The administration of capsaicin (orally) and CGRP (intravenously) significantly enhanced the WIR-induced increases in the gastric tissue level of prostaglandins 30 min after WIR, whereas CGRP-(8-37), a CGRP receptor antagonist, significantly inhibited them. Pretreatment with Nomega-nitro-L-arginine methyl ester (L-NAME), a nonselective inhibitor of nitric oxide (NO) synthase (NOS), and that with indomethacin inhibited the WIR-induced increases in gastric tissue levels of prostaglandins, whereas either pretreatment with aminoguanidine (AG), a selective inhibitor of the inducible form of NOS, or that with NS-398, a selective inhibitor of cyclooxygenase (COX)-2, did not affect them. CPZ, the functional denervation of capsaicin-sensitive sensory neurons, and CGRP-(8-37) significantly increased gastric MPO activity and exacerbated the WIR-induced gastric mucosal injury in rats subjected to 4-h WIR. The administration of capsaicin and CGRP significantly increased the gastric tissue levels of prostaglandins and inhibited both the WIR-induced increases in gastric MPO activity and gastric mucosal injury 8 h after WIR. These effects induced by capsaicin and CGRP were inhibited by pretreatment with L-NAME and indomethacin but not by pretreatment with AG and NS-398. These observations strongly suggest that capsaicin-sensitive sensory neurons might release CGRP, thereby increasing the gastric tissue levels of PGI2 and PGE2 by activating COX-1 through activation of the constitutive form of NOS in rats subjected to WIR. Such activation of capsaicin-sensitive sensory neurons might contribute to the reduction of WIR-induced gastric mucosal injury mainly by inhibiting neutrophil activation.

Role of microthrombus formation in the development of ischemia/reperfusion-induced liver injury in rats

Although tumor necrosis factor-a (TNF-alpha) has been shown to play a critical role in the pathologic process leading to ischemia/reperfusion (I/R)-induced liver injury in rats by activating neutrophils, it is not clear whether or not microthrombus formation induced by TNF-alpha contributes to the liver injury. In the present study, we investigated the role of microthrombus formation in I/R-induced liver injury in rats. Hepatic tissue levels of TNF-alpha were significantly increased after reperfusion, and these were higher in animals subjected to 120 min-hepatic I/R than in those subjected to 60 min-hepatic I/R. Fibrin deposition was observed histologically in the hepatic sinusoidal space only in animals subjected to 120 min-hepatic I/R. Both the decrease in hepatic tissue blood flow and the extent of liver injury in animals subjected to 60 min- and 120 min-hepatic I/R were significantly inhibited by pretreatment with anti-rat TNF-a antibody. Although neutrophil elastase inhibitors inhibited the decrease in hepatic tissue blood flow and reduced liver injury in animals subjected to 60 min-hepatic Y/R, anticoagulants did not show any effects. Both anticoagulants and neutrophil elastase inhibitors inhibited the decrease in hepatic tissue blood flow and reduced liver injury in animals subjected to 120 min-hepatic I/R. Therapeutic effects of anti-rat TNF-a antibody on the 120 min-I/R-induced liver injury were more marked than those of each anticoagulant or each neutrophil elastase inhibitor, and were comparable to those of combined use of anticoagulants and neutrophil elastase inhibitors. These observations strongly suggest that TNF-alpha induces I/R-induced liver injury primarily by activating neutrophils, and it exacerbates liver injury by inducing microthrombus formation when the production of TNF-alpha is further increased.

Antithrombin reduces ischemia/reperfusion-induced renal injury in rats by inhibiting leukocyte activation through promotion of prostacyclin production

Antithrombin (AT) supplementation in patients with severe sepsis has been shown to improve organ failures in which activated leukocytes are critically involved. However, the precise mechanism(s) for the therapeutic effects of AT is not well understood. We examined in rats whether AT reduces ischemia/reperfusion (I/R)-induced renal injury by inhibiting leukocyte activation. AT markedly reduced the I/R-induced renal dysfunction and histologic changes, whereas neither dansyl glutamylglycylarginyl chloromethyl ketone-treated factor Xa (DEGR-F.Xa), a selective inhibitor of thrombin generation, nor Trp49-modified AT, which lacks affinity for heparin, had any effect. Renal tissue levels of 6-keto-PGF(1 alpha), a stable metabolite of prostacyclin (PGI(2)), increased after renal I/R. AT enhanced the I/R-induced increases in renal tissue levels of 6-keto-PGF(1 alpha), whereas neither DEGR-F.Xa nor Trp49-modified AT had any effect. AT significantly inhibited I/R-induced decrease in renal tissue blood flow and the increase in the vascular permeability. Ischemia/reperfusion-induced increases in renal tissue levels of tumor necrosis factor-alpha, cytokine-induced neutrophil chemoattractant, and myeloperoxidase were significantly inhibited in animals given AT. Pretreatment of animals with indomethacin reversed the effects induced by AT. Iloprost, an analog of PGI(2), produced effects similar to those induced by AT. These observations strongly suggest that AT reduces the I/R-induced renal injury by inhibiting leukocyte activation. The therapeutic effects of AT might be mainly mediated by PGI(2) released from endothelial cells through interaction of AT with cell surface glycosaminoglycans.

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.

Prostaglandin E1 reduces compression trauma-induced spinal cord injury in rats mainly by inhibiting neutrophil activation

Prostaglandin E1 (PGE1), a potent vasodilator, was recently reported to inhibit both neutrophil activation and monocytic production of tumor necrosis factor-alpha (TNF-alpha) in vitro. We previously reported that TNF-alpha was critically involved in the development of motor disturbances by increasing the accumulation of neutrophils at the site of injury in rats subjected to compression trauma-induced spinal cord injury. Therefore, it is possible that PGE1 reduces motor disturbances by inhibiting neutrophil activation in rats subjected to spinal cord injury. We examined this possibility in a rat model of spinal cord injury (SCI). Motor disturbances induced by spinal cord compression were evaluated using the inclined plane test, and footprint analysis. Accumulation of neutrophils at the site of trauma was evaluated by measuring tissue myeloperoxydase (MPO) activity. Tissue levels of TNF-alpha were determined using an enzyme-linked immunosorbent assay. Motor disturbances induced by spinal cord compression were significantly attenuated in rats administered PGE1. A histological examination revealed that intramedullary hemorrhages, observed 24 h after trauma, were markedly reduced in animals administered PGE1. Increases in the tissue levels of TNF-alpha and MPO activity in the damaged segment of spinal cord were significantly inhibited in animals that had received PGE1. These observations suggested that PGE1 reduces motor disturbances by inhibiting neutrophil activation directly or indirectly through the inhibition of TNF-alpha production at the site of injury. These effects of PGE1 might at least partly contribute to therapeutic effect on SCI in rats.