tcv-309 and Reperfusion-Injury

Ischaemia and reperfusion (IR) of the small bowel is involved in many clinical conditions. A key component in IR-induced tissue damage is microvascular dysfunction. The aim was to investigate the role of leucocytes and platelets in capillary flow impediment and tissue damage.. Anaesthetized rats were subjected to 30 min warm ischaemia of the small bowel, followed by 1 h reperfusion. To elucidate the influence of leucocytes on platelet adhesion, leucocyte-vessel wall interactions induced by IR were prevented by anti-platelet activating factor (PAF) or anti-intercellular adhesion molecule (ICAM)-1. Intravital videomicroscopy was performed and tissue injury was evaluated histologically.. In submucosal venules, IR induced an increase in the median number of interacting leucocytes from 3 to 10 and 20 leucocytes per 100-microm venule segment after 10 and 60 min reperfusion respectively. Anti-PAF or anti-ICAM-1 completely attenuated this increase, resulting in an eightfold improvement in submucosal capillary flow and reduced tissue injury. Shedding of villi no longer occurred. Platelet-vessel wall interactions occurred particularly in submucosal venules, but were not affected by anti-PAF or anti-ICAM-1.. Small bowel IR initiated an inflammatory and thrombotic response in the submucosal layer only. Attenuation of leucocyte adhesion improved submucosal capillary perfusion, preventing shedding of mucosal villi.

Topics: Animals; Antibodies, Monoclonal; Blood Flow Velocity; Capillaries; Cell Adhesion; Intercellular Adhesion Molecule-1; Intestine, Small; Leukocytes; Microcirculation; Platelet Activating Factor; Platelet Adhesiveness; Platelet Aggregation Inhibitors; Pyridinium Compounds; Random Allocation; Rats; Rats, Inbred Lew; Reperfusion; Reperfusion Injury; Tetrahydroisoquinolines; Warm Ischemia

Our previous study suggested that inflammatory mediators released due to IRI lead to host's immune response by upregulating MHC II in the host's peripheral T lymphocytes. This study hypothesized the role of platelet-activating factor (PAF) in the mechanism of induced MHC II upregulation due to IRI on peripheral T lymphocytes. The objectives of this study were to investigate the role of PAF in the induction of host immune reactivity and the protective effect of PAF-antagonist TCV-309 in combination with prostaglandin E1 (PGE1) against the host's immune response caused by IRI. Thirty female domestic swine were divided into three groups. Group A (6 donors, 6 recipients) had no pharmacological intervention. Group B (6 donors, 6 recipients) was the experimental group treated with TCV-309 + PGE1. Group C underwent sham operation. The ex vivo preservation time for groups A and B was 4 hr at 4 degrees C. To detect the changes in MHC II expression on T cells due to IRI, blood samples were collected before reperfusion (baseline level), 1, 2, and 3 days post-reperfusion. Two-colour flow cytometry analysis (FACS) was used to study MHC II-DR-beta expression in peripheral T lymphocytes. Swine anti-MHC II and anti-CD3 antibodies were used for this purpose. The FACS analyses demonstrated that in group A, there was a significant increase (p < 0.05) in MHC II intensity on peripheral T lymphocytes on day 2 post-reperfusion. By the third day post-reperfusion, MHC intensity had a tendency to decrease but did not reached the baseline level. In group B and C, however, there was no significant change in the level of MHC II in T lymphocytes at any of the post-reperfusion times. In group A, the number of CD3+MHC+ T lymphocytes significantly decreased (p < 0.05) by one day post-reperfusion and remained at this level until the third day post-reperfusion. In groups B and C, no significant change in the number of CD3+MHC+ T cells was observed. The results of this study suggested that the release of inflammatory mediators (e.g. PAF) due to IRI played a role in the mechanism of IRI-induced host's immune response. The results also suggested that the combination of TCV-309 + PGE1 could reduce this immune response.

Topics: Alprostadil; Animals; Female; Histocompatibility Antigens Class II; Inflammation Mediators; Infusions, Intravenous; Isoquinolines; Platelet Activating Factor; Pyridinium Compounds; Regression Analysis; Reperfusion Injury; Swine; T-Lymphocyte Subsets; Tetrahydroisoquinolines; Up-Regulation

This study was designed to verify the involvement of platelet-activating factor (PAF) in renal damage associated with hepatic ischemia and reperfusion (HIR) injury through the release of endothelin (ET)-1 and to determine the modulating effect of a specific PAF receptor antagonist on these insults in rats.. Male rats pretreated with either normal saline as a vehicle (NS group) or intravenous TCV-309, a PAF receptor antagonist (TCV group), were subjected to 120 min of total hepatic ischemia under an extracorporeal portosystemic shunt. Plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight were determined under nonischemic conditions and at 1, 3, and 6 hr of reperfusion after hepatic ischemia. Changes in mean arterial blood pressure and renal tissue blood flow measurements in the kidney were determined throughout the experiment.. Increased plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight after HIR in the NS group were significantly suppressed by TCV-309 pretreatment. Mean arterial blood pressure and renal tissue blood flow after HIR in the TCV group were significantly improved when compared with those in the NS group. These effects resulted in attenuation of structural hepatic and renal damage with the improvement of 7-day survival (62%).. The present study demonstrates that renal damage as well as critical liver injury is produced after reperfusion following 120 min of total hepatic ischemia. A PAF receptor antagonist may be therapeutically useful to protect against these types of damage via indirect modulation of plasma ET-1 levels.

Topics: Animals; Aspartate Aminotransferases; Blood Pressure; Blood Urea Nitrogen; Creatinine; Endothelin-1; Ischemia; Isoquinolines; Kidney; Liver; Liver Circulation; Male; Platelet Activating Factor; Platelet Aggregation Inhibitors; Platelet Membrane Glycoproteins; Pyridinium Compounds; Rats; Rats, Sprague-Dawley; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Reperfusion Injury; Tetrahydroisoquinolines

Pathophysiologic changes of posttransplant lung ischemia/reperfusion injury are mediated by redundant cellular and humoral mechanisms. We investigated the protective effect of combined administration of platelet activating factor (PAF) and endothelin (ET) antagonists after prolonged ischemia in a small animal lung transplantation model.. Orthotopic left lung transplantation was performed after 20 hours cold ischemia in male Fischer (F344) rats weighing 200-250 g. Group I served as control. In Group II, donors received 1 mg/kg body weight of the endothelin antagonist TAK-044, and recipients 2 mg/kg. Group III was treated with the PAF antagonist TCV-309 (donor: 50 microg/kg; recipient: 100 microg/kg) (Takeda Chemicals Ltd.). Group IV received a combined treatment with both substances at the same dosage. Twenty-four hours after reperfusion, the native contralateral lung was occluded to assess gas exchange of the graft only, and 5 minutes later the thoracic aorta was punctured for arterial blood gas analysis (n = 5). In other animals (n = 5), lung tissue was frozen 24 hours after reperfusion and assessed for myeloperoxidase activity (MPO) and thiobarbituric acid reactive substances.. Combined inhibition of PAF and ET-1 at the receptor level resulted in significantly improved graft function as compared to controls (Group I), and to groups treated with either TAK-044 or TCV-309. This was determined by a higher arterial oxygen content (112 +/- 9 mmHg, p = .00061 vs control, 48 +/- 5 mmHg), reduced MPO activity (0.35 +/- 0.02 deltaOD/mg/min, p = .000002 vs control, 1.1 +/- 0.1 deltaOD/mg/min) and reduced lipid peroxidation (59.5 +/- 2.5 pmol/g, p = .011 vs control, 78.5 +/- 4.1 pmol/g). The improvement of arterial oxygen (Group II 77 +/- 10 mmHg, p = .027 vs control; Group III 84 +/- 8 mmHg, p = .0081 vs control) and reduction of MPO activity (Group II 0.85 +/- 0.061 deltaOD/mg/min, p = .017; Group III 0.92 +/- 0.079 deltaOD/mg/min, p = .058) in groups treated with either a PAF antagonist or an ET antagonist was significantly less than in Group IV.. Combined donor and recipient treatment with an ET antagonist and a PAF antagonist results in superior posttransplant graft function 24 hours after reperfusion, suggesting a synergistic role of ET-1 and PAF in the mediation of reperfusion injury in this model. Single treatment with either of the antagonists revealed only a slight improvement compared to untreated controls.

Topics: Animals; Drug Therapy, Combination; Endothelin Receptor Antagonists; Isoquinolines; Lipid Peroxidation; Lung; Lung Transplantation; Male; Oxygen; Peptides, Cyclic; Peroxidase; Platelet Activating Factor; Pyridinium Compounds; Rats; Rats, Inbred F344; Reperfusion Injury; Tetrahydroisoquinolines; Thiobarbituric Acid Reactive Substances

Ischemia-reperfusion injury is one of the major problems in organ transplantation. The role of platelet-activating factor (PAF) in the pathophysiology of ischemia-reperfusion injury and the protective effect of a novel phospholipid PAF analog (TCV-309) alone and combined with prostaglandin E1 (PGE1) is investigated in an extended (20 hours) ex vivo lung preservation.. Forty-two swine were divided into three groups. Group A was the control. In groups B and C, the effect of PAF was blocked with TCV-309 administered 1 hour before cross-clamping for donor and recipient. Group C received PGE1 50 micrograms bolus in the donor pulmonary plegia, and the recipients received a 50 micrograms bolus plus 0.003 microgram/kg/min infusion at the time of implantation. Donor lungs were perfused with cold modified Collins solution and maintained in hypothermic storage (4 degrees C) for 20 hours. Hemodynamics, lung mechanics, gas exchange, and biochemistry were assessed before transplantation (donor) and at 30 minutes and 24 hours after reperfusion (recipient). At 24 hours after reperfusion, the histopathologic condition of transplanted lungs was evaluated.. Radioimmunoassay demonstrated a significant (p < 0.001) increase in the production of PAF and TXB2 in transplanted lungs at 24 hours after transplantation for group A only. Hemodynamics, gas-exchange parameters, and lung compliance were significantly (p < 0.05) better after transplantation for groups B and C. Wet lung weight was significantly less (p < 0.05) for group C. Semiquantitative morphometric analysis demonstrated the highest degree of damage for group A compared with groups B and C. A strong correlation (r2 = 70) between lung weight and histologic injury scores was observed among groups.. This study suggests that PAF is responsible in part for the deleterious effects of ischemia and reperfusion, that PAF-antagonist TCV-309 protects lungs from extended (20 hours) ischemic injury, and that PGE1 seems to have an additional beneficial effect.

Topics: Alprostadil; Animals; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Hemodynamics; Isoquinolines; Lung; Lung Transplantation; Organ Preservation; Platelet Aggregation Inhibitors; Pulmonary Gas Exchange; Pyridinium Compounds; Reperfusion Injury; Respiratory Mechanics; Swine; Tetrahydroisoquinolines

The purpose of this study was to investigate whether treatment with TCV-309, a PAF antagonist, improves life-sustaining function of renal grafts that have suffered warm ischemia (WI) prior to cold storage (CS) and whether TCV-309 influences leukocyte sequestration in tissues. Syngeneic kidneys with 20 min of WI and 24 hr of CS were transplanted into bilateral nephrectomized rats. In the treated group, TCV-309 was administered (i.v. 1 mg/kg) 5 min before reperfusion. Rats in the control group received saline. On day 14, 80% rats survived in the treated group, which was higher than the controls (0%). At 24 hr of reperfusion, myeloperoxidase (MPO) activity, a marker enzyme for PMNs, in the treated kidney was significantly lower than the controls, but did not differ from the normal values. The MPO activity in the controls was higher than the normal values. In conclusion, the PAF antagonist improves posttransplant function of rat kidneys subjected to a period of WI and CS. PMNs are involved in postischemic renal injury, which is, at least partially, mediated by PAF. The effectiveness of PAF antagonist in treatment of recipients may lead to its clinical application in transplantation of ischemically injured kidneys.

Topics: Animals; Hot Temperature; Immunity, Cellular; Ischemia; Isoquinolines; Kidney; Kidney Cortex; Kidney Transplantation; Lung; Macrophages; Monocytes; Neutrophils; Organ Preservation; Peroxidase; Platelet Activating Factor; Platelet Aggregation Inhibitors; Pyridinium Compounds; Rats; Rats, Inbred Lew; Reperfusion Injury; Tetrahydroisoquinolines; Time Factors

Topics: Animals; Ischemia; Isoquinolines; Kidney; Kidney Tubules, Proximal; Male; Microvilli; Mitochondrial Swelling; Platelet Activating Factor; Pyridinium Compounds; Rats; Rats, Inbred Lew; Reperfusion Injury; Tetrahydroisoquinolines; Time Factors

Topics: Animals; Carbon Dioxide; Dogs; Isoquinolines; Lung; Lung Transplantation; Organ Preservation; Oxygen; Partial Pressure; Peroxidase; Platelet Activating Factor; Pulmonary Artery; Pulmonary Veins; Pyridinium Compounds; Reperfusion; Reperfusion Injury; Tetrahydroisoquinolines

Topics: Animals; Creatinine; Ischemia; Isoquinolines; Kidney; Male; Microscopy, Video; Organ Preservation; Platelet Activating Factor; Pyridinium Compounds; Rats; Rats, Inbred Lew; Reperfusion Injury; Temperature; Tetrahydroisoquinolines

The aim of this study was to evaluate: (1) the accumulation of leukocytes in the ileum and the lung during splanchnic artery occlusion (SAO) shock; (2) the role of platelet-activating factor (PAF) and tumor necrosis factor (TNF-alpha) in this phenomenon. Untreated anesthesized rats subjected to total occlusion of the celiac, superior and inferior mesenteric arteries for 45 min, followed by reperfusion, uniformly died within 90 min after reperfusion. The mean survival time was 93 +/- 7 min. The neutrophilic infiltrate was quantitated in the ileum and in the lung using a myeloperoxidase (MPO) assay. MPO activity in the ileum and in the lung averaged 0.05 +/- 0.03 and 0.4 +/- 0.02 U x 10(-3)/g protein in animals killed before occlusion. MPO activity did not change in rats killed immediately before reperfusion and was significantly elevated (0.11 +/- 0.02 and 1.7 +/- 0.6 U x 10(-3)/g protein in the ileum and the lung, respectively) in those killed 80 min after the beginning of the reperfusion. The histological examination confirmed the accumulation of leukocytes in the mucosa of the ileum and the lung over the 80 min. SAO shocked rats exhibited leukopenia and increased serum levels of TNF-alpha. In order to evaluate the role of PAF and TNF-alpha in SAO shock, a powerful PAF receptor antagonist, TCV-309 (5 micrograms/kg i.v.), was injected 5 min after reperfusion. TCV-309 increased survival time, lowered serum TNF-alpha, reduced MPO activity in both the ileum and the lung and ameliorated leukopenia induced by SAO shock.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Arterial Occlusive Diseases; Blood Pressure; Ileum; Isoquinolines; Leukocyte Count; Leukocytes; Lung; Male; Neutrophils; Peroxidase; Platelet Activating Factor; Pyridinium Compounds; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Splenic Artery; Tetrahydroisoquinolines; Tumor Necrosis Factor-alpha

The effects of TCV-309, a specific platelet-activating factor (PAF) antagonist, and OP-41483, a prostaglandin I2 analogue, on warm ischemia/reperfusion injury of the rat liver were studied. Rats were divided into five groups by the duration of warm ischemia and the treatment used. The NS1 group (normal saline pretreatment) had 60 min of warm ischemia, while the NS2 group (normal saline pretreatment), the PGI2 group (OP-41483, 500 ng/kg/min pretreatment), the TCV group (TCV-309, 3 micrograms/kg), and the PGI2+TCV group (both the above dosages) underwent 120 min of warm ischemia. Postoperative survival after 30 days, bile secretion, serum endotoxin levels, and tissue glutathione levels after 60 min of reperfusion were compared between the groups. The survival rates for the NS1, NS2, PGI2, TCV, and PGI2+TCV groups were 80%, 0%, 50%, 80%, and 86.7%, respectively. Bile secretion, which has a strong correlationship with hepatic cellular ATP level, was strongly correlated with survival. The NS2 group had a high serum endotoxin level--however, the PGI2 and PGI2+TCV groups had normal levels. Although there were some discrepancies between survival and the tissue glutathione level, combined treatment with the PGI2 analogue and TCV-309 was most effective in inhibited oxidative stress. In conclusion, TCV-309 increased the survival rate after 120 min of warm hepatic ischemia without endotoxemia by the PGI2 analogue. This finding suggest that warm ischemia/reperfusion injury is related to the generation of PAF. Combined pretreatment with TCV-309 and a PGI2 analogue may be useful in liver transplantation.

Topics: Animals; Bile; Endotoxins; Epoprostenol; Glutathione; Ischemia; Isoquinolines; Liver; Male; Platelet Activating Factor; Pyridinium Compounds; Rats; Rats, Wistar; Reperfusion Injury; Tetrahydroisoquinolines

Topics: Animals; Dogs; Ischemia; Isoquinolines; Leukocyte Count; Lung; Lung Compliance; Platelet Activating Factor; Pulmonary Circulation; Pyridinium Compounds; Reperfusion Injury; Tetrahydroisoquinolines; Vascular Resistance