The effect of tissue factor pathway inhibitor on hepatic ischemic reperfusion injury of the rat

rTFPI Protects Cardiomyocytes from Hypoxia/Reoxygenation Injury through Inhibiting Autophagy and the Class III PI3K/Beclin-1 Pathway

Autophagy plays various roles at different stages of ischemia reperfusion (I/R) injury in cardiomyocytes. It has been reported that tissue factor pathway inhibitor (TFPI) has a protective effect on I/R injury. This study aimed to determine the roles of TFPI in autophagy during the I/R injury process in cardiomyocytes and the possible mechanisms. An isolated hypoxia/reoxygenation (H/R) pattern of cardiomyocytes was established by the MIC101 system. The cell viability and oxidative stress of cardiomyocytes were detected by an MTT assay and ROS assay, respectively. The autophagy level was measured by Ad-mCherry-GFP-LC3B and MDC. We detected the expression levels of autophagy-related proteins by western blotting. After 2 h of hypoxia and 12 h of reoxygenation, the cardiomyocyte viability in the H/R group was significantly lower than that in the control group (p < 0.05) than in the H/R group. According to intracellular ROS production, the fluorescence intensity in the H/R group was enhanced compared with that in the negative control group, and it was weaker in the H/R + rTFPI group compared with the H/R group. The level of autophagy and the expression levels of autophagy-related proteins (LC3-II/LC3-I, Beclin-1 and PI3K) were markedly increased in the H/R group compared to the control group (p < 0.05) whereas the levels were markedly decreased in the H/R + rTFPI group compared to the H/R group (p < 0.05). TFPI could relieve cardiomyocyte injury by inhibiting the Class III PI3K/Beclin-1 pathway and oxidative stress; thus, TFPI decreased autophagy and protected cardiomyocytes induced by H/R injury. In conclusion, TFPI may be a new direction for the prevention of myocardial I/R injury.

Inhibition of thrombin on endothelium enhances recruitment of regulatory T cells during IRI and when combined with adoptive Treg transfer, significantly protects against acute tissue injury and prolongs allograft survival

Ischemia-reperfusion injury (IRI) amplifies T cell alloimmune responses after transplantation with thrombin playing a key pro-inflammatory role. To explore the influence of thrombin on regulatory T cell recruitment and efficacy we used a well-established model of IRI in the native murine kidney. Administration of the cytotopic thrombin inhibitor PTL060 inhibited IRI, and by skewing expression of chemokines (reducing CCL2 and CCL3 but increasing CCL17 and CCL22) increased the infiltration of M2 macrophages and Tregs. When PTL060 was combined with infusion of additional Tregs, these effects were further amplified. To test the benefits of thrombin inhibition in a transplant model, BALB/c hearts were transplanted into B6 mice with or without perfusion with PTL060 in combination with Tregs. Thrombin inhibition or Treg infusion alone led to small increments in allograft survival. However, the combined therapy led to modest graft prolongation by the same mechanisms as in renal IRI; graft survival was accompanied by increased numbers of Tregs and anti-inflammatory macrophages, and reduced expression of pro-inflammatory cytokines. While the grafts succumbed to rejection associated with the emergence of alloantibody, these data suggest that thrombin inhibition within the transplant vasculature enhances the efficacy of Treg infusion, a therapy that is currently entering the clinic to promote transplant tolerance.

Hepatic ischemia/reperfusion injury is diminished by atorvastatin in Wistar rats

BACKGROUND AND AIMS

Temporal occlusion of the hepatoduodenal ligament (HDL) is often used during liver surgeries in order to reduce blood loss, resulting in ischemia/reperfusion injury (I/R). The aim of the study was to investigate the effects of atorvastatin (ATOR) on hepatic I/R injury and on serum levels of tumor necrosis factor-alpha (TNF-α), endothelin-1 (ET-1), antithrombin III (ATIII) and intracellular adhesion molecule-1 (ICAM-1).

METHODS

Liver ischemia was induced in Wistar rats by clamping the HDL for 60 min, followed by either 60 or 180 min reperfusion. Rats received either vehicle or 10 mg/kg ATOR before hepatic I/R. Control group received sham surgery. Livers were examined for histological damage and serum AST, ALT, TNF-α, ET-1, ATIII and ICAM-1 concentrations were measured.

RESULTS

After I/R, AST and ALT were significantly elevated, ATIII levels were significantly depleted, both TNF-α and ICAM-1 levels increased and ET-1 was significantly elevated (at 180 min). ATOR pretreatment attenuated these alterations and diminished histological injury scores.

CONCLUSIONS

Our results show that ATOR protects the liver from I/R injury.

Effect of ONO-4057 and tacrolimus on ischemia-reperfusion injury of the liver

AIM: To investigate the effects of a novel Leukotriene B₄ receptor antagonist and/or tacrolimus on ischemia-reperfusion in a rat liver model.

METHODS: Male Lewis rats were pretreated with ONO-4057 (100 mg/kg) and/or tacrolimus (1 mg/kg) orally, and divided into four experimental groups; group 1 (control), group 2 (ONO-4057), group 3 (tacrolimus), group 4 (ONO-4057 + tacrolimus).

RESULTS: There was a tendency for long survival in the groups treated with tacrolimus alone and ONO-4057 plus tacrolimus. Post-reperfusion serum aspartate aminotransferase levels decreased more significantly in ONO-4057 plus tacrolimus group (P < 0.01), than in the tacrolimus alone group (P < 0.05), compared to controls.

CONCLUSION: This study demonstrated that pretreatment with ONO-4057 in combination with tacrolimus produced additive effects in a rat model of liver ischemia-reperfusion injury.

Tissue factor-dependent coagulation contributes to alpha-naphthylisothiocyanate-induced cholestatic liver injury in mice

Separation of concentrated bile acids from hepatic parenchymal cells is a key function of the bile duct epithelial cells (BDECs) that form intrahepatic bile ducts. Using coimmunostaining, we found that tissue factor (TF), the principal activator of coagulation, colocalized with cytokeratin 19, a marker of BDECs in the adult mouse liver. BDEC injury induced by xenobiotics such as alpha-naphthylisothiocyanate (ANIT) causes cholestasis, inflammation, and hepatocellular injury. We tested the hypothesis that acute ANIT-induced cholestatic hepatitis is associated with TF-dependent activation of coagulation and determined the role of TF in ANIT hepatotoxicity. Treatment of mice with ANIT (60 mg/kg) caused multifocal hepatic necrosis and significantly increased serum biomarkers of cholestasis and hepatic parenchymal cell injury. ANIT treatment also significantly increased liver TF expression and activity. ANIT-induced activation of the coagulation cascade was shown by increased plasma thrombin-antithrombin levels and significant deposition of fibrin within the necrotic foci. ANIT-induced coagulation and liver injury were reduced in low-TF mice, which express 1% of normal TF levels. The results indicate that ANIT-induced liver injury is accompanied by TF-dependent activation of the coagulation cascade and that TF contributes to the progression of injury during acute cholestatic hepatitis.

Activated protein C prevents hepatic ischaemia-reperfusion injury in rats

BACKGROUND

Hepatic ischaemia-reperfusion injury (IRI) is a serious complication of liver surgery, especially extended hepatectomy and liver transplantation. Activated protein C (APC), a potent anticoagulant serine protease, has been shown to have cell-protective properties by virtue of its anti-inflammatory and anti-apoptotic activities.

METHODS

The present study was designed to examine the cytoprotective effects of APC in a 60-min warm-IRI rat model.

RESULTS

Following a single intravenous injection of APC before reperfusion, APC exerted cytoprotective effects 4 h after reperfusion, as evidenced by: (i) decreased levels of transaminase and improved histological findings of IRI, (ii) reduced infiltration and activation of neutrophils, macrophages and T cells, (iii) reduced expression of tumour necrosis factor-alpha, (iv) reduced expression of P-selectin and intracellular adhesion molecule-1, (v) inhibited coagulation and attenuated sinusoidal endothelial cell injury, (vi) improved hepatic microcirculation and (vii) decreased transferase-mediated dUTP nick end-labelling-positive cells. These effects of APC were observed 4 h but not 24 h after reperfusion. However, multiple injections of APC after reperfusion significantly decreased the levels of transaminase and the activity of myeloperoxidase, and improved histological findings of IRI 24 h after reperfusion.

CONCLUSION

These results suggest that APC is a promising therapeutic option for hepatic warm-IRI; however, multiple injections of APC are necessary to maintain its cell-protective action over the long term.

Changes in tissue factor and the effects of tissue factor pathway inhibitor on transient focal cerebral ischemia in rats

INTRODUCTION

To determine the contribution of tissue factor (TF) to focal cerebral ischemia/reperfusion injury, we investigated the changes in TF in rat brains with transient focal cerebral ischemia and also assessed the effect of TF pathway inhibitor (TFPI).

MATERIALS AND METHODS

Spontaneous hypertensive rats were subjected to 90-min of middle cerebral artery occlusion (MCAO) and then were reperfused for up to 24 h. Immediately after MCAO, recombinant human TFPI (rhTFPI) (50 or 20 microg/kg/min) was administered by means of a continuous intravenous injection for 4.5 h.

RESULTS AND CONCLUSIONS

TF immunoreactivity decreased or scattered in the ischemic area after reperfusion, however, an increased TF expression was observed in the microvasculature with the surrounding brain parenchyma and it peaked at 3 to 6 h, which coincided with the start of fibrin formation. On the other hand, total TF protein in ischemic area continued to exist and did not remarkably change until 24 h after reperfusion. At 24 h after reperfusion, the total infarct volume in the group treated with 50 microg/kg/min rhTFPI was significantly smaller than that in the controls (saline). Western blotting and immunohistochemical studies showed that rhTFPI treatment resulted in a decrease of fibrin in the ischemic brains and microvasculature. TF-mediated microvascular thrombosis is thus considered to contribute to focal cerebral ischemia/reperfusion injury. The continuous infusion of rhTFPI until a peak of TF-mediated microvascular thrombosis therefore attenuates the infarct volume by reducing fibrin deposition in the cerebral microcirculation.

Prospects of antisense oligodeoxynucleotides to alleviate renal ischaemia-reperfusion injury

Renal ischaemia-reperfusion (I/R) injury is a clinically significant problem and an invariable consequence of renal transplantation. The problem begins at the onset of acute tubular necrosis (ATN), when the transplantation takes a long ischaemic interval by using the cardiac arrest donor's kidney. In addition, the longer the ischaemic interval, the higher the incidence rate of ATN. It is clinically important that renal I/R injury is reduced. The antisense oligodeoxynucleotide (AS-ODN), developed as a therapy for intractable diseases at the gene level, has recently been established as an important method in examining specific gene functions. The authors have previously demonstrated that AS-ODN/tissue factor (TF) prevents renal I/R injury. This review discusses the efficacy of AS-ODN/TF and AS-ODN/intercellular adhesion molecule-1 as existing targets, and the potential of AS-ODN/nuclear factor-kappaB, AS-ODN/cyclooxygenase and AS-ODN/5-lipoxygenase as prospective targets.

Identification and characterization of murine alternatively spliced tissue factor

Tissue factor (TF) is a transmembrane glycoprotein that initiates coagulation and plays a critical role in regulating hemostasis and thrombosis. We have recently reported a naturally occurring, soluble form of human tissue factor (asTF) generated by alternative splicing. This splice variant has a novel C-terminus with no homology to that of the full-length TF (flTF), lacks a transmembrane domain, and is active in the presence of phospholipids. Mouse models offer unique opportunities to examine the relative importance of flTF and asTF in mediating thrombosis, the response to arterial injury, and ischemic damage. To that end, we have identified and characterized murine asTF (masTF). Like the human splice variant, masTF lacks a transmembrane domain and has a unique C-terminus. We have generated antibodies specific to masTF and murine flTF (mflTF) to examine the expression of both forms of TF. masTF antigen is widely and abundantly expressed, with a pattern similar to that of mflTF, in adult tissues, in experimentally induced thrombi, and during development. These studies demonstrate that masTF contributes to the pool of total TF and may thus play an important role in mediating TF-dependent processes.

Gadolinium chloride and salvia miltiorrhiza compound ameliorate reperfusion injury in hepatocellular mitochondria

AIM: To investigate the effect of gadolinium chloride (GaCl₃) and salvia miltiorrhiza compound (SMCo) on ischemia and reperfusion (I/R) injury in hepatocellular mitochondria.

METHODS: Wistar rats were randomly to divided into control group, GaCl₃ group, SMCo group and GaCl₃ + SMCo group (n = 15 each). GaCl₃ (7 mg·kg^-1) was injected into tail vein on d 1 and d 2 in contrast group. SMCo (2 mL·kg^-1) was injected into muscle on d 1 and d 2 in SMCo group. GaCl₃ + SMCo group received both GaCl₃ (iv) and SMCo (im) injection. Control group received saline injection only. On d 3, all the rats were subjected to 2 h ischemia in the middle and left lobes of the liver, followed by reperfusion for 2 h, 6 h and 18 h respectively. The level of serum alanine aminotransferase (ALT) and malondialdehyde (MDA) in hepatocellular mitochondria was measured. Pathological changes in hepatic tissue and in hepatocellular mitochondria were determined with optical microscope and electronic microscope, respectively.

RESULTS: Remarkablly pathohistological and biochemical changes were detected after 6 h of I/R. Compared with control, the level of ALT was decreased in GaCl₃, SMCo and GaCl₃ + SMCo treated groups (1314.0 ± 278.7 vs 809.4 ± 196.1, 716.6 ± 242.8 and 837.2 ± 190.6 IU·L^-1, respectively. P < 0.05). Similarly, the level of MDA was decreased in GaCl₃, SMCo and GaCl₃ + SMCo treated groups (293.1 ± 51.1 vs 190.8 ± 55.5, 214.3 ± 32.9 and 221.0 ± 47.3 nmol·g^-1, respectively, P < 0.05). Accordingly, in control group, swelling, degeneration, focal necrosis, infiltration of leucocyte were found in reperfused tissue under an optical microscope, and mitochondria swelling, rupture and even breakdown were seen under an electronic microscope. These pathohistological and ultrastructural damages caused by I/R were greatly attenuated in GaCl₃, SMCo and GaCl₃ + SMCo treated groups. However, there was no additive effect observed when GaCl₃ and SMCo were used together.

CONCLUSION: Both GaCl₃ and SMCo can alleviate the I/R injury in hepatocellular mitochondria.

Bench-to-bedside review: functional relationships between coagulation and the innate immune response and their respective roles in the pathogenesis of sepsis

The innate immune response system is designed to alert the host rapidly to the presence of an invasive microbial pathogen that has breached the integument of multicellular eukaryotic organisms. Microbial invasion poses an immediate threat to survival, and a vigorous defense response ensues in an effort to clear the pathogen from the internal milieu of the host. The innate immune system is able to eradicate many microbial pathogens directly, or innate immunity may indirectly facilitate the removal of pathogens by activation of specific elements of the adaptive immune response (cell-mediated and humoral immunity by T cells and B cells). The coagulation system has traditionally been viewed as an entirely separate system that has arisen to prevent or limit loss of blood volume and blood components following mechanical injury to the circulatory system. It is becoming increasingly clear that coagulation and innate immunity have coevolved from a common ancestral substrate early in eukaryotic development, and that these systems continue to function as a highly integrated unit for survival defense following tissue injury. The mechanisms by which these highly complex and coregulated defense strategies are linked together are the focus of the present review.

Antisense oligonucleotide for tissue factor inhibits hepatic ischemic reperfusion injury

Tissue factor (TF) is an initiation factor for blood coagulation and its expression is induced on endothelial cells during inflammatory or immune responses. We designed an antisense oligodeoxynucleotide (AS-1/TF) for rat TF and studied its effect on hepatic ischemic reperfusion injury. AS-1/TF was delivered intravenously to Lewis rats. After 10 h, hepatic artery and portal vein were partially clamped. Livers were reperfused after 180 min and harvested. TF expression was studied using immunohistochemical staining. One of 10 rats survived in a 5-day survival rate and TF was strongly stained on endothelial cells in non-treatment group. However, by treatment with AS-1/TF, six of seven survived and TF staining was significantly reduced. Furthermore, we observed that fluorescein-labeled AS-1/TF was absorbed into endothelial cells. These results suggest that AS-1/TF can strongly suppress the expression of TF and thereby inhibit ischemic reperfusion injury to the rat liver.

The role of tissue factor in renal ischemic reperfusion injury of the rat

BACKGROUND

Tissue factor (TF) is a membrane-bound glycoprotein that is the primary cellular initiator of the blood clotting cascade and its expression is induced on macrophages and endothelial cells during the inflammatory or immune response. Tissue factor pathway inhibitor (TFPI) regulates the extrinsic pathway of blood coagulation through its ability to inhibit tissue factor activity. We studied the role of TF in the kidney following warm ischemic reperfusion and studied the effect of TFPI in vivo.

MATERIALS AND METHODS

After laparotomy of Lewis rats, the right kidney was harvested and left renal artery and vein were clamped. The kidney was reperfused after 60, 120, and 180 min of ischemia. Rats were sacrificed at 0, 1.5, 5, 12, and 24 h after reperfusion with or without TFPI treatment, and the kidney was harvested. Blood samples were collected at 0, 5, 12, and 24 h after reperfusion from the abdominal aorta. Blood urea nitrogen and kalium were monitored. TF expression was also studied by immunohistochemical staining with a monoclonal antibody (HTF-K108).

RESULTS

Histologically, the necroses of the tubular epithelial cells were observed 1.5 h after reperfusion. Immunohistochemically, TF staining was positive on the glomerular endothelial cells and stimulated monocytes but negative on the tubular epithelial cells. The necrotic area extended and encompassed almost all of the ischemic kidney by 12 h after reperfusion. TF was stained on the glomerular base membrane, the glomerular endothelial cells, and the stimulated monocytes but was not evident on the necrotic tubular epithelial cells. Fibrinogen was also observed in the glomerular endothelial cells at 5-12 h after reperfusion, while it was slight in normal tissue. With TFPI treatment, the necrotic area was narrow and TF was slightly stained on the endothelial cells.

CONCLUSIONS

These results suggest that TF plays an important role in the development of renal injury after ischemia and reperfusion. The microcirculatory incompetence due to microthrombus might cause the formation and development of the necrosis. These results also suggest that TFPI plays a key role in modulating tissue factor-dependent blood coagulation, therefore TFPI is a strong medication for prevention of ischemic reperfusion injury.

Endogenous heparin decreases the thrombotic response to hemorrhagic shock in rabbits

PURPOSE

The purpose of this study was to determine if endogenous heparin release would modulate the hemostatic response to hemorrhagic shock in rabbits.

MATERIALS AND METHODS

Anesthetized rabbits (n = 13) underwent hemorrhagic shock (MAP 30-40 mm Hg) for 60 minutes. Blood samples obtained before and 60 minutes after hemorrhagic shock had thrombelasto-graphic variables (R, reaction time [min]; angle, alpha [ degrees ]; and G [dynes/cm(2)]) determined. Hemostatic function was assessed by modified thrombelastography under four conditions: (1) unmodified sample; (2) platelet inhibition with cytochalasin D; (3) heparinase I exposure; and (4) platelet inhibition and heparinase I exposure.

RESULTS

Thrombelastographic variable values in samples without platelet inhibition or heparinase exposure did not significantly change after hemorrhage (before hemorrhage: R = 22.01 +/- 0.7 min, alpha 43.6 +/- 1.3 degrees, G 7,089 +/- 379 dyne/cm(2); after hemorrhage: R 22.1 +/- 2.4, alpha 41.6 +/- 3.9, G = 5,662 +/- 564; mean +/- SEM). However, blood samples exposed to heparinase after hemorrhage demonstrated enhanced hemostatic function with thrombelastographic values (R = 13.4 +/- 1.5, alpha 56.0 +/- 3.4, G = 7012 +/- 565) significantly different (P <.05) from samples not exposed to heparinase. Samples with platelet inhibition demonstrated a similar pattern.

CONCLUSION

Hemorrhagic shock significantly increased circulating endogenous heparin activity, attenuating the thrombotic response to hemorrhage in rabbits. Heparin-mediated regulation of hemostasis may serve as a protective mechanism in shock states.

Beneficial effect of FR167653 on cold ischemia/reperfusion injury in rat liver transplantation

BACKGROUND

Proinflammatory cytokines such as interleukin 1-beta (IL-1beta) and tumor necrosis factor-a (TNF-alpha) play an important role in the development of hepatic ischemia/reperfusion injury. FR167653 has been characterized as a potent suppressant of IL-1beta and TNF-alpha production. The aim of this study was to evaluate the effect of FR167653 on cold ischemia/ reperfusion injury in rat liver transplantation.

METHODS

Donor livers were preserved with cold University of Wisconsin solution for 48 hr and transplanted orthotopically. Immediately after reperfusion, FR167653 (1 mg/kg, FR-treated group) or normal saline solution (control group) was administered i.v.. The severity of liver injury was determined by hepatic enzyme levels as well as by histological findings. The accumulation of IL-1beta and TNF-alpha mRNA in the liver was analyzed by semi-quantitative reverse transcription-polymerase chain reaction. Tissue factor expression was subjected to immunohistochemical analysis.

RESULTS

In the FR-treated group, release of aspartate aminotransferase and alanine aminotransferase after reperfusion was significantly lower (P<0.05 and P<0.02, respectively), and histological liver injury was less prominent, than in the control group. Accumulation of IL-1beta and TNF-alpha mRNA was suppressed in the FR-treated liver. Tissue factor expression on Kupffer cells and sinusoidal endothelial cells, marked in the control group, was almost absent in the FR-treated group. Seven-day survival in the FR-treated group (75%) was significantly better than that in the control group (12.5%) (P<0.01).

CONCLUSIONS

These results indicate that treatment with FR167653 ameliorates cold ischemia/reperfusion injury in liver transplantation.

Role of tissue factor-mediated coagulation in ischemia/ reperfusion-induced injury of Langendorf-perfused rabbit hearts

BACKGROUND

Production of oxygen free radicals, and activation of neutrophils and plasma complement contribute to myocardial reperfusion injury, but the role of coagulation has not been assessed.

OBJECTIVE

To characterize tissue-factor-mediated generation of thrombin and its association with tissue injury during reperfusion from normothermic ischemia of isolated, Langendorf-perfused rabbit hearts.

METHODS

Activation of coagulation was assessed by addition of 12% rabbit plasma and human fibrinogen to Krebs-Henseleit-buffer perfusate with measurement of levels of human fibrinopeptide A (hFPA) in the heart effluent as an index of thrombin-mediated formation of fibrin.

RESULTS

Concentrations of hFPA in the effluent were minimal during non-ischemic perfusion (5 +/- 5 ng/ml, n=6) and during 50 min of ischemia (13 +/- 3 ng/ml, n=6), but increased markedly during the first 20 min of reperfusion (to 41 +/- 29 ng/ml, P=0.03 versus before reperfusion). Addition to the perfusate of 10 microg/ml recombinant human tissue-factor-pathway inhibitor, the physiologic inhibitor of tissue-factor-mediated coagulation, abolished increases in the level of hFPA after reperfusion. However, indexes of myocardial injury manifested during reperfusion, including decrease in recovery of left ventricular pressure developed, increase in left ventricular end-diastolic pressure, and increase in activity of creatine kinase in the heart effluent, were not improved by anticoagulation with recombinant human tissue-factor-pathway inhibitor.

CONCLUSION

Our results do not support the hypothesis that coagulation plays a major role in ischemia/reperfusion injury of Langendorf-perfused rabbit hearts.