Biomedical subjects

M Ioculano

Publications and source records attributed to M Ioculano.

At least 19 recordsLinked to original sources

PubMed1997

The effects of recombinant human granulocyte-colony stimulating factor on vascular dysfunction and splanchnic ischaemia-reperfusion injury.

1. The aim of our study was to investigate the effects of recombinant human granulocyte-colony stimulating factor in a rat model of splanchnic ischaemia-reperfusion injury. 2. Male anaesthetized rats were subjected to clamping of the splanchnic arteries for 45 min. This surgical procedure resulted in an irreversible state of shock (splanchnic artery occlusion shock. SAO shock). Sham operated animals were used as controls. Survival rate, serum tumour necrosis factor-alpha (TNF-alpha), neutrophil count, bone marrow myeloid precursor cells, myeloperoxidase activity (MPO; studied as a quantitative means to assess leukocyte accumulation), mean arterial blood pressure and the responsiveness of aortic rings to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% at 4 h of reperfusion, while sham shocked rats survived more than 4 h), increased serum levels of TNF-alpha (201 +/- 10 u ml-1; sham shocked rats = undetectable), neutropenia, enhanced MPO activity in the ileum (0.11 +/- 0.06 u x 10(-3) g-1 tissue; sham shocked rats = 0.02 +/- 0.001 u x 10(-3) g-1 tissue) and in the lung (1.5 +/- 0.2 u x 10(-3) g-1 tissue; sham shocked rats = 0.19 +/- 0.05 u x 10(-3) g-1 tissue) and unchanged bone marrow myeloid precursor cells. Furthermore aortic rings from shocked rats showed a marked hyporeactivity to PE. 4. Administration of recombinant human granulocyte colony stimulating factor (rh G-CSF; 5, 10 and 20 micrograms kg-1 5 min following the release of occlusion) increased in a dose-dependent manner survival rate (90% at 4 h of reperfusion with the dose of 20 u x 10(-3) g kg-1), reduced serum TNF-alpha (13 +/- 5 u ml-1) and MPO activity in the ileum (0.065 +/- 0.002 u x 10(-3) g-1 tissue) and in the lung (0.7 +/- 0.03 microgram kg-1 tissue), improved neutropenia and mean arterial blood pressure but did not modify bone marrow myeloid progenitor cells. Furthermore rh G-CSF, either in vivo or in vitro (200 nM for 1 h in the organ bath), restored to control values the hyporeactivity to PE. Finally rh G-CSF potently inhibited the activity of inducible nitric oxide synthase in peritoneal macrophages activated with endotoxin. 5. Our results suggest that rh G-CSF protects against splanchnic ischaemia reperfusion injury by a mechanism(s) that does not depend upon its haematopoietic effects.

Animals↗

PubMed1996

Leukocyte integrin very late antigen-4/vascular cell adhesion molecule-1 adhesion pathway in splanchnic artery occlusion shock.

We investigated the role played by the very late antigen-4 (VLA-4)/ vascular cell adhesion molecule-1 (VCAM-1) interaction in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, serum tumour necrosis factor (TNF-alpha), monocyte and lymphocyte cell count and the responsiveness to acetylcholine of aortic rings were studied. Furthermore we investigated the VCAM-1 expression on vessel endothelium and the percentage of VLA-4 positive leukocytes. Splanchnic artery occlusion shocked rats had a decreased survival time (76 +/- 10 min, while sham shocked rats survived more than 4 h), increased serum levels of TNF-alpha (328 +/- 11 U/ml), a decreased number of both monocytes and lymphocytes and reduced responsiveness to acetylcholine (10 nM-10 microM) of aortic rings. In addition we found an increased expression of endothelial VCAM-1 on aortic rings and a reduced percentage of VLA-4 positive lymphocytes and monocytes. Passive immunization with specific antibodies raised against either VCAM-1 or VLA-4 (2 mg/kg, i.v., 3 h before splanchnic artery occlusion shock) increased survival, improved monocyte and lymphocyte count and restored the responsiveness of aortic rings to acetylcholine (P < 0.01). Finally, inhibition of TNF-alpha biosynthesis reversed the increased endothelial expression of VCAM-1 and the reduced percentage of integrin VLA-4 positive leukocytes. Our findings suggest that (i) VLA-4/VCAM-1 interaction has a role in the pathogenesis of circulatory shock; (ii) this interaction might be a target for new therapeutic approaches to the therapy of low-flow states.

Acetylcholine↗

PubMed1996

Endotoxin tolerance impairs a pertussis-toxin-sensitive G-protein regulating tumour necrosis factor release by macrophages from tumour-bearing rats.

The aim of this work was to study whether a G-protein regulates lipopolysaccharide (LPS) induced TNF-alpha production in tumour-bearing rat peritoneal macrophages differently to in normal rats. We also investigated whether a state of 'early endotoxin tolerance' affects LPS induced TNF-alpha release via a G-protein-mediated phenomenon. LPS-stimulated (50 micrograms ml-1 of Salmonella enteritidis LPS) TNF-alpha release was investigated in peritoneal macrophages harvested from both normal rats and tumour-bearing rats. Cholera toxin (10, 100 and 1000 ng ml-1) did not significantly modify LPS-induced TNF-alpha release. In contrast pertussis toxin (0.1, 1.0 and 10 ng ml-1) significantly increased LPS-induced TNF-alpha release and inhibited LPS-stimulated prostaglandin E2 (PGE2) production in both normal rat macrophages and tumour-bearing rat macrophages. Pertussis toxin effects on these LPS responses were correlated with a pertussis-toxin-mediated ADP-ribosylation of a 41 kDa protein(s). The LPS-mediated responses were significantly greater in macrophages from tumour-bearing rats than in macrophages from normal rats. PGE2 (10(-9), 10(-8) and 10(-7) M) suppressed LPS-induced TNF-alpha production in a dose-dependent fashion. A state of 'early endotoxin tolerance' was then induced in tumour-bearing rats by a single intravenous injection of 125 micrograms rat-1 of LPS, and experiments were performed on peritoneal macrophages harvested 24 h after LPS injection. In tolerant macrophages pertussis toxin induced an increase in LPS-stimulated TNF-alpha release and an inhibition in LPS-stimulated PGE2 release significantly lower than in macrophages harvested from non-tolerant tumour bearing rats. Our results suggest that a pertussis-toxin-sensitive G-protein may serve to regulate the synthesis of TNF-alpha in rat peritoneal macrophages and that the activity of this pertussis-sensitive G-protein is increased in macrophages from tumour-bearing rats. Furthermore, our experiments would indicate that a 'state of endotoxin tolerance', caused by altering the function of presumably a Gi-protein, may exert beneficial effects on the functions of macrophages in tumour-bearing rats.

Adenosine Diphosphate Ribose↗

PubMed1996

Monocytes and lymphocytes as active participants in the pathogenesis of experimental shock.

We investigated the role played by monocytes and lymphocytes in the pathogenesis of experimental shock. Splanchnic artery occlusion (SAO) shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min followed by reperfusion. Sham operated animals were used as controls. SAO shocked rats had a decreased survival time (80 +/- 11 min, while sham shocked rats survived more than 4 h), increased serum (248 +/- 21 U/ml) and macrophage (145 +/- 15 U/ml) levels of TNF-alpha, enhanced myeloperoxidase (MPO) activity in the ileum (3.38 +/- 0.2 U x 10(-3)/g tissue), decreased number of monocytes, lymphocytes and neutrophils and a profound hypotension. In addition we found an increased expression of vascular cell adhesion molecule-1 (VCAM-1) on aortic endothelium and a reduced percentage of VLA-4 positive monocytes and lymphocytes. Inhibition of TNF-alpha synthesis, reversed the increased endothelial expression of VCAM-1, increased the percentage of integrin VLA-4 positive leukocytes and improved monocyte, lymphocyte and neutrophil count. Furthermore a passive immunization with specific antibodies raised against VCAM-1 (2 mg/kg, i.v. 3 h before SAO) increased survival, reduced MPO activity in the ileum (0.034 +/- 0.04 U x 10(-3)/g tissue) and improved mean arterial blood pressure. Our data suggest that monocytes and lymphocytes participate in the pathogenesis of splanchnic ischaemia-reperfusion injury and may amplify the adhesion of neutrophils to peripheral tissues.

Animals↗

PubMed1996

Thrombolytic therapy with urokinase reduces increased circulating endothelial adhesion molecules in acute myocardial infarction.

The aim was to investigate circulating E-selectin and Intercellular Adhesion Molecule-1 (ICAM-1) in acute myocardial infarction. Our study was carried out in 80 patients, 40 hospitalized for acute myocardial infarction (AMI), 20 suffering from chronic stable angina and 20 healthy control subjects. Samples of venous blood were taken from all patients at the moment of hospitalization and after 2, 4, 6, 8, 10, 12 and 24 hours from the thrombolytic treatment (AMI + urokinase) or conventional therapy (AMI + nitroglycerin), for the dosage of creatinine kinase (CK) and adhesion molecules. The CK was determined by means of a Hitachi 901 automatic analyser using an enzymatic method (reagents Boheringer-Biochemia, Germany). Soluble E-selectin (sE-selectin) and soluble ICAM-1 (sICAM-1) were measured in the serum using a specific immunoassay (British Biotechnology Products). The serum levels of Tumor Necrosis Factor (TNF-alpha) were evaluated using an immunoenzymatic assay to quantitate the serum levels of the cytokine (British Biotechnology Products). Patients with acute myocardial infarction (AMI) had increased serum levels of soluble E-selectin (sE-selectin; AMI + urokinase = 312 +/- 20 ng/ml; AMI + nitroglycerin = 334 +/- 15 ng/ml) and soluble ICAM-1 (sICAM-1; AMI + urokinase = 629 +/- 30 ng/ml; AMI + nitroglycerin = 655 +/- 25 ng/ml) compared to both patients with chronic angina (sE-selectin = 67 +/- 10 ng/ml; sICAM-1 = 230 +/- 20 ng/ml) and healthy control subjects (sE-selectin = 53 +/- 15 ng/ml; sICAM-1 200 +/- 16 ng/ml). Furthermore patients with acute myocardial infarction also had increased serum levels of Tumor Necrosis Factor (TNF-alpha = 309 +/- 10 pg/ml; control subjects = 13 +/- 5 pg/ml). Thrombolytic therapy with urokinase (1,000,000 IU as an intravenous bolus for 5 minutes, followed by an infusion of an additional 1,000,000 IU for the following two hours) succeeded in producing reperfusion and reduced the serum levels of sE-selectin (52 +/- 13 ng/ml) and sICAM-1 (202 +/- 31 ng/ml). In contrast patients not eligible for thrombolytic therapy and therefore treated with conventional therapy (a continuous i.v. infusion of nitroglycerin at the dose of 50 mg/die) did not show any significant reduction in both sE-selectin and sICAM-1 throughout the study. Our results confirm previous experimental data and indicate that adhesion mechanisms supporting leukocyte-endothelium interaction may also be operative in human acute myocardial infarction.

Adult↗

PubMed1996

Effects of S-ethylisothiourea, a potent inhibitor of nitric oxide synthase, alone or in combination with a nitric oxide donor in splanchnic artery occlusion shock.

1. The aim of this study was to compare the effects of an intravenous infusion of a potent and non selective nitric oxide synthase inhibitor S-ethylisothiourea (Ethyl-TU) with that of a nitric oxide (NO) donor on the pathological sequelae associated with splanchnic artery occlusion (SAO) shock. In addition the effects of the combination of these two treatments were also investigated. 2. SAO shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase activity (MPO; studied as a quantitative means to evaluate neutrophil accumulation) and the responsiveness of aortic rings to acetylcholine (ACh, 10 nM-10 microM) and to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% survival 2 h after the release of occlusion) and survival time (76 +/- 10 min), increased MPO activity in the ileum (3.39 +/- 0.8 u x 10(-3) g-1 tissue), a marked leukopenia and a profound hypotension. In addition aortic rings from shocked rats showed a marked hyporeactivity to PE and reduced responsiveness to ACh. Endothelium denuded aortic rings had also a marked hyporeactivity to PE. 4. In vivo administration of Ethyl-TU (0.1 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) significantly increased survival time and rate, improved mean arterial blood pressure, restored the responsiveness to PE, but did not change MPO activity, leukopenia or the impairment in the responsiveness of aortic rings to ACh. Addition of Ethyl-TU (2 microM) to endothelium denuded aortic rings in vitro, restored the marked hyporeactivity to PE. Administration of the NO donor C87-3754 (0.75 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) slightly increased survival time and reduced MPO activity and leukopenia, but did not change survival rate and mean arterial blood pressure. In addition C87-3754 restored the responsiveness of aortic rings to ACh to control values, but did not modify the hyporeactivity to PE. The combination of these two interventions produced a higher degree of protection than either Ethyl-TU or C87-3754 alone. In fact, co-administration of Ethyl-TU plus C87-3754 completely prevented mortality, reduced MPO activity, attenuated leukopenia and the profound hypotension and restored the impaired responsiveness of aortic rings to PE and ACh. 5. Our study suggests that treatment with a nitric oxide synthase inhibitor combined with an NO donor may be a new therapeutic approach to the treatment of splanchnic artery occlusion shock.

Acetylcholine↗

PubMed1996

Protection of ischemic and reperfused rat myocardium by the nonglucocorticoid 21-aminosteroid U-74389G, a new inhibitor of lipid peroxidation.

We studied the effects of the aminosteroid U-74389G (21-[4-(2, 6-di-1-pyrrolidinyl-4-pyrimidinyl)-1-piperazinyl]-pregna-1,4,9(11)- triene-3,20-dione(2)-2-butenenedionate), a putative inhibitor of lipid peroxidation, which protects the rat myocardium after ischemia and reperfusion. Pentobarbital-anesthetized (50 mg/kg) rats were subjected to 60 min of occlusion of the left main coronary artery followed by 60 min of reperfusion. Myocardial ischemia/reperfusion produced a large cardiac necrosis (81 +/- 8.6% of the area at risk and 65 +/- 14.8% of the total left ventricle), polymorphonuclear infiltration in the jeopardized tissue (myeloperoxidase activity = 4.2 +/- 2.1 U X 10(-3)/g tissue in the area at risk and 7.0 +/- 3.6 U X 10(-3)/g tissue in the necrotic area), hydroxyl radical (OH.) formation (0.55 +/- 0.16 nmol/ml), increased plasma malonylaldehyde (40.2 +/- 3.9 nmol/ml) and lactate dehydrogenase (431 +/- 30 mIU/ml) and caused a decrease in the survival rate. Treatment with U-74389G (15 and 30 mg/kg i.v.) at the onset of reperfusion caused a reduction of necrotic area expressed as a percentage of either the area at risk (76 +/-7.4% with 15 mg/kg and 69 +/- 13.5% with 30 mg/kg; P < .05) or the total left ventricle (53 +/- 13.6% with 15 mg/kg and 46 +/- 16.8% with 30 mg/kg; P < .05). Treatment U-74389G reduced the myeloperoxidase activity, evaluated as an index of neutrophil infiltration, both in the area at risk (2.7 +/- 1.1 and 2.2 +/- 1.7 U X 10(-3)/g tissue with the doses of 15 and 30 mg/kg, respectively; P < .05) and in the necrotic area (4.3 +/- 2.4 and 3.8 +/- 2.9 U X 10(-3)/g tissue with 15 and 30 mg/kg, respectively; P < .05); decreased OH. formation (measured indirectly by the administration of the trapping agent salicylic acid); and analyzing the hydroxylation product 2,5-dihydroxybenzoic acid during reperfusion (0.35 +/- 0.12 and 0.32 +/- 0.15 nmol/ml with the doses of 15 and 30 mg/kg, respectively; P < .005). Treatment inhibited lipid peroxidation by blunting plasma malonylaldehyde (26.7 +/- 3.1 and 20.8 +/- 3.3 with the doses of 15 and 30 mg/kg, respectively; P < .001), prevented cellular disruption by reducing the increase of plasma lactate dehydrogenase (288.6 +/- 28 and 201.3 +/- 16 mIU/ml with the doses of 15 and 30 mg/kg, respectively; P < .001). Finally, U-74389G enhanced the survival rate evaluated at the end of the experiment (from 40 to 87%). These outcomes suggest that the drug may have potential for cardioprotective use in acute myocardial infarction.

Animals↗

PubMed1995

G 619, a dual thromboxane synthase inhibitor and thromboxane A2 receptor antagonist, inhibits tumor necrosis factor-alpha biosynthesis.

G 619 is 3-carbamyl-(3'-picolyl)-4-methoxy-1-benzamide. The compound is structurally related to picotamide, a previously reported dual thromboxane synthase inhibitor/thromboxane A2 receptor antagonist, which displays inhibitory activity on tumor necrosis factor-alpha. The aim of the present work was to study the effect of G 619 on tumor necrosis factor-alpha synthesis both in vivo and in vitro. Salmonella enteritidis lipopolysaccharide was used to induce tumor necrosis factor-alpha production. Septic shock was produced in male rats by a single intravenous (i.v.) injection of 20 mg/kg (LD90) of Salmonella enteritidis lipopolysaccharide. Rats were pretreated with G 619 (50 mg/kg, i.v.) or vehicle (1 ml/kg, i.v.) 1 h before endotoxin challenge. Salmonella enteritidis lipopolysaccharide administration dramatically reduced survival rate (0%, 72 h after endotoxin administration), reduced mean arterial blood pressure, increased plasma levels of thromboxane B2 and 6-keto-prostaglandin F1 alpha and enhanced serum levels of tumor necrosis factor. Furthermore, endotoxic shock produced characteristic gastric damage, consisting of haemorrhagic infiltrates. Pretreatment with G 619 in vivo significantly protected against Salmonella enteritidis lipopolysaccharide-induced lethality (80% survival rate and 60% survival rate 24 h and 72 h after Salmonella enteritidis lipopolysaccharide injection, respectively), reduced hypotension, decreased plasma thromboxane B2 and serum tumor necrosis factor-alpha levels and enhanced blood levels of 6-keto-prostaglandin F1 alpha. In rat peritoneal macrophages, G 619 in vitro (25, 50 and 100 microM) significantly blunted (P < 0.001) Salmonella enteritidis lipopolysaccharide-stimulated production of tumor necrosis factor-alpha, whereas it increased 6-keto-prostaglandin F1 alpha and cyclic AMP levels. The present data indicate that G 619 may be useful during disease states characterized by elevated tumor necrosis factor-alpha levels.

6-Ketoprostaglandin F1 alpha↗

PubMed1995

E-selectin involvement in the pathogenesis of splanchnic artery occlusion shock.

We investigated the involvement of E-selectin in the pathogenesis of splanchnic artery occlusion shock. Splanchnic artery occlusion shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham-operated animals were used as controls. Survival time, serum tumor necrosis factor-alpha, while blood cell count, mean arterial blood pressure and myeloperoxidase activity were determined. Splanchnic artery occlusion-shocked rats had a decreased survival time (85 +/- 8 min, while sham-shocked rats survived more than 4 h), reduced mean arterial blood pressure, increased serum levels of tumor necrosis factor-alpha (186 +/- 9 U/ml) and myeloperoxidase activity in the ileum (0.10 +/- 0.04 U x 10(-3)/g tissue) and in the lung (1.5 +/- 0.06 U x 10(-3)/g tissue). Shocked rats showed histological alterations in the ileum and in the lung. Administration of a hyperimmune serum containing specific antibodies raised against E-selectin significantly increased survival time (225 +/- 10 min), reduced leukopenia and myeloperoxidase activity both in the ileum (0.035 +/- 0.001 U x 10(-3)/g tissue) and in the lung (0.3 +/- 0.005 U x 10(-3)/g tissue), improved the cardiovascular changes and reduced the histological alterations in the ileum and lung. Our data are consistent with an involvement of E-selectin in the pathogenesis of splanchnic artery occlusion shock.

Animals↗

PubMed1995

Tumour necrosis factor mediates E-selectin production and leukocyte accumulation in myocardial ischaemia-reperfusion injury.

The aim of our study was to examine the mechanism of E-selectin production and leukocyte accumulation in myocardial ischaemia-reperfusion injury. Myocardial injury was induced in anaesthetized rats by the clamping of the left main coronary artery followed by reperfusion. After thoracotomy a silk suture was placed under the left coronary artery. The ligature was tied for a period of 1 h and after this period it was untied and the ischaemic myocardium was reperfused for 1 h (MI/R rats) or removed (SHAM MI/R rats). Myocardial ischaemia plus reperfusion in untreated rats decreased survival rate, produced a marked myocardial necrosis, enhanced cardiac myeloperoxidase activity (a marker enzyme commonly used to assess polymorphonuclear leukocyte infiltration) and increased serum creatinephosphokinase (CPK) activity, serum levels of tumour necrosis factor-alpha (TNF-alpha) and serum levels of soluble E-selectin (sE-selectin). Furthermore, MI/R rats had an increased pressure rate index studied as a quantitative means for assessing myocardial oxygen demand. Administration of cloricromene, an inhibitor of TNF-alpha, reduced TNF-alpha production, significantly lowered serum sE-selectin levels, blunted leukocyte accumulation in the ischaemic myocardium and protected the myocardium from injury due to ischaemia and reperfusion. The results of the present study show an involvement of E-selectin in vivo in the pathogenesis of myocardial ischaemia and reperfusion and suggest that TNF-alpha may induce in vivo the production of a specific adhesion mechanism which sustains leukocyte infiltration.

Animals↗

PubMed1995

Improved survival and reversal of endothelial dysfunction by the 21-aminosteroid, U-74389G in splanchnic ischaemia-reperfusion injury in the rat.

1. Anaesthetized rats subjected to total occlusion of the superior mesenteric artery and the coeliac trunk for 45 min developed a severe shock state (splanchnic artery occlusion, SAO shock) resulting in death within 70-90 min after release of the occlusion. Sham-operated animals were used as controls. 2. Survival rate, survival time, serum tumour necrosis factor (TNF-alpha), white blood cell (WBC) count, mean arterial blood pressure (MAP), plasma malonyladehyde (MAL); myeloperoxidase activity (MPO) and the responsiveness to acetylcholine (ACh 10 nM-10 microM) of aortic rings were investigated. 3. SAO shocked rats had a decreased survival rate and survival time (74 +/- 10 min, while sham-shocked rats survived more than 4 h), reduced mean arterial blood pressure, increased serum levels of TNF-alpha (267 +/- 13 u ml-1) and plasma levels of MAL (57 +/- 7 nmol ml-1), enhanced MPO activity in the ileum (0.23 +/- 0.04 u x 10(-3) g-1 tissue) and in the lung (2.2 +/- 0.8 u x 10(-3) g-1 tissue), leukopenia and reduced responsiveness to ACh of aortic rings. 4. The 21-aminosteroid U-74389G (30 mg kg-1, i.v.) increased survival (survival time = 232 +/- 15 min), lowered the serum levels of TNF-alpha and the plasma levels of MAL, reduced leukopenia and MPO activity both in the ileum (0.021 +/- 0.004 u x 10(-3) g-1 tissue) and in the lung (0.23 +/- 0.03 u x 10(-3) g-1 tissue), improved MAP and restored the responsiveness to ACh of aortic rings. 5. Our data suggest that U-74389G is a potent lipid peroxidation inhibitor and that it has antishock and endothelial protective actions.

Acetylcholine↗

PubMed1995

Tumor necrosis factor induces E-selectin production in splanchnic artery occlusion shock.

Splanchnic arteries were clamped for 45 min to induce splanchnic artery occlusion (SAO) shock in anesthetized rats. Sham-operated animals were used as controls. Survival time, serum tumor necrosis factor-alpha (TNF-alpha), white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase (MPO) activity, and serum levels of soluble E-selectin (sE-selectin) were investigated. SAO-shocked rats exhibited decreased survival time (95 +/- 11 min, whereas sham-shocked rats survived for > 5 h), reduced mean arterial blood pressure, increased serum levels of TNF-alpha (185 +/- 8 U/ml) and MPO activity in the ileum (0.11 +/- 0.03 U x 10(-3)/g tissue) and lung (1.5 +/- 0.4 U x 10(-3)/g tissue), leukopenia, and enhanced serum levels of sE-selectin. Furthermore SAO-shocked rats showed histological alterations in the ileum and lung. Administration of cloricromene (2 mg/kg i.v.), an inhibitor of TNF-alpha, significantly increased survival time (225 +/- 10 min), decreased serum levels of TNF-alpha and sE-selectin, reduced leukopenia and MPO activity in the ileum (0.035 +/- 0.003 U x 10(-3)/g tissue) and lung (0.3 +/- 0.005 U x 10(-3)/g tissue), improved the cardiovascular changes, and reduced the histological changes in the ileum and lung. Finally, an anti-E-selectin antibody protected rats against SAO shock. Our findings are consistent with an involvement of E-selectin, "in vivo," in the pathogenesis of SAO shock.

Animals↗

PubMed1994

Antibodies against intercellular adhesion molecule 1 protect against myocardial ischaemia-reperfusion injury in rat.

In this study we have assayed the pathophysiological role of intercellular adhesion molecule (ICAM-1), a cytokine-inducible adhesion molecule, in a model of ischaemia reperfusion in the rat. Anaesthetized rats were subjected to occlusion (1 h) of the left main coronary artery followed by reperfusion (1 h). Sham myocardial ischaemia-reperfusion rats (Sham MI/R) were used as controls. Myocardial ischaemia plus reperfusion in untreated rats decreased survival rate, produced a marked myocardial necrosis, increased serum creatine phosphokinase activity, and cardiac myeloperoxidase activity (a marker enzyme commonly used to assess polymorphonuclear leukocyte accumulation). Furthermore, rats subjected to myocardial ischaemia-reperfusion showed an increased pressure rate index, studied as a quantitative means for assessing myocardial oxygen demand. Treatment with monoclonal anti-rat ICAM-1 (1 mg/kg i.v.), 3 h before occlusion of the left main coronary artery, significantly lowered serum creatine phosphokinase activity, blunted leukocyte accumulation and protected the myocardium from injury subsequent to ischaemia and reperfusion injury. These investigations have revealed that ICAM-1 is a critical adhesion molecule in the pathogenesis of ischaemia-reperfusion injury. In addition these results suggest that the use of monoclonal antibodies raised against ICAM-1 can represent a useful tool for the prevention of ischaemia-reperfusion damage.

Analysis of Variance↗

PubMed1994

E-selectin in the pathogenesis of experimental myocardial ischemia-reperfusion injury.

The role of E-selectin in the pathogenesis of an experimental model of myocardial ischemia-reperfusion injury was investigated. Pentobarbital anesthetized rats underwent left main coronary artery ligation (1 h) followed by reperfusion (1 h; MI/R). Sham operated rats were used as controls (sham MI/R). Myocardial ischemia-reperfusion injury reduced survival rate (50%), caused severe myocardial damage (necrotic area/area-at-risk 69.8 +/- 5%; necrotic area/total area = 56 +/- 7.6%), increased serum creatine phosphokinase activity (sham MI/R = 33 +/- 3 U/ml; MI/R = 215 +/- 13 U/ml), and elevated myeloperoxidase activity (investigated as an index of leukocyte adhesion and accumulation; sham MI/R = 0.11 +/- 0.02 U x 10(-3)/g tissue) in the area-at-risk (7.5 +/- 1.7 U x 10(-3)/g tissue) and in the necrotic area (7.8 +/- 2.2 U x 10(-3)/g tissue). Furthermore, MI/R rats had an increased pressure rate index, studied as a quantitative means for assessing myocardial oxygen demand. Administration of a hyperimmune serum containing antibodies against E-selectin significantly improved survival rate (80%), reduced myocardial injury (necrotic area/area-at-risk = 26.4 +/- 7%, P < 0.005; necrotic area/total area 19.1 +/- 2.8%, P < 0.005), lowered serum creatine phospokinase activity (85 +/- 5 U/ml, P < 0.001) and decreased myeloperoxidase activity in the area at risk (3.7 +/- 1.3 U x 10(-3)/g tissue, P < 0.001) and in the necrotic area (3.0 +/- 0.7 U x 10(-3)/g tissue). Finally, the administration of anti E-selectin antibodies improved the PRI in MI/R rats. The present data suggest that E-selectin in vivo plays a key role in the pathogenesis of myocardial ischemia/reperfusion injury.

Animals↗

PubMed1994

TCV-309, a novel platelet activating factor antagonist, inhibits leukocyte accumulation and protects against splanchnic artery occlusion shock.

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)

Animals↗

PubMed1994

Reduction of myocardial infarct size in rat by IRFI-048, a selective analogue of vitamin E.

The effects of IRFI-048 (2,3-dihydro-5-methoxy-4,6,7-trimethyl-2-benzofuranyl acetic acid), a selective analogue of Vitamin E, on myocardial tissue injury were examined in anaesthetized rats subjected to 60-min occlusion of the left coronary artery followed by 60-min reperfusion. Infarct size (Evan's blue and tetrazolium stain), serum creatinphosphokinase (CPK), plasma malonaldehyde (MAL), cardiac myeloperoxidase (MPO) activity, and ST-segment of electrocardiogram (ECG) and survival rate were evaluated. Postischaemic reperfusion produced severe cardiac necrosis, caused neutrophil (PMNs) infiltration (evaluated by MPO activity) in the jeopardized tissue, increased serum CPK and plasma MAL, raised ST-segment of ECG, and decreased survival rate. IRFI-048, (200 and 400 mg/kg o.s.) given to the rats 6 h before occlusion, caused a reduction of necrotic area expressed as a percentage of either the area at risk or the total left ventricle, decreased MPO activity both in the area at risk (from 3.2 +/- 0.3 U x 10(-3)/g tissue to 1.1 +/- 0.4 U x 10(-3)/g tissue; p < .005) and in the necrotic area (from 5.7 +/- 0.9 U x 10(-3)/g tissue to 1.8 +/- 0.5 U x 10(-3)/g tissue; p < .001), attenuated the rise of ST-segment of ECG (from 0.51 +/- 0.14 mV in the vehicle group to 0.28 +/- 0.11 mV in the treated group; p < .005), reduced the increase of plasma MAL and serum CPK during reperfusion (from 42 +/- 5.3 nmol/ml to 15 +/- 3.1 nmol/ml and 139 +/- 13 IU/100 ml to 58 +/- 7.5 IU/100 ml, respectively; p < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗

PubMed1994

Protective effects of L-659,989, a platelet-activating factor receptor antagonist, in myocardial ischemia and reperfusion in rats.

The cardioprotective effects of L-659,989, a specific platelet-activating factor (PAF) receptor antagonist, were investigated in an ischemia/reperfusion model in rats. Pentobarbital-anesthetized rats were subjected to left main coronary artery occlusion (1 h) followed by reperfusion (1 h) (MI/R); Sham-operated rats were used as controls (Sham MI/R). Rats receiving vehicle showed reduced survival rate (60%), marked myocardial injury (necrotic area/total area = 54.5 +/- 6%; necrotic area/area at risk 76.6 +/- 6.7%), high serum creatine phosphokinase (CPK) activity (150 +/- 10 U/ml), and increased myocardial myeloperoxidase (MPO) activity in the area at risk (AR, 6.2 +/- 0.5 U x 10(-3)/g protein) and in the necrotic area (6.6 +/- 0.7 U x 10(-3)/g protein). PAF plasma levels increased significantly during reperfusion and peaked at 15 min of reperfusion. Administration of L-659,989 enhanced survival rate (80%), reduced myocardial damage (necrotic area/total area 25.6 +/- 3.5%; necrotic area/AR 34.6 +/- 5.4%), attenuated the increase in serum CPK (50 +/- 6 U/ml) and decreased MPO activity both in the AR (2.8 +/- 0.3 U x 10(-3)/g tissue) and in the necrotic area (2.3 +/- 0.5 U x 10(-3)/g tissue). Our results suggest that PAF-inducing adhesion and activation of polymorphonuclear leukocytes (PMN) plays a significant role in the injury associated with ischemia/reperfusion.

Animals↗

PubMed1994

Participation of tumour necrosis factor and nitric oxide in the mediation of vascular dysfunction in splanchnic artery occlusion shock.

1. Splanchnic artery occlusion (SAO) shock is characterized by irreversible circulatory failure. Tumour necrosis factor (TNF-alpha) may affect the L-arginine/nitric oxide (NO) pathway, thus contributing to the cardiovascular derangements of circulatory shock. 2. We investigated the contribution of both TNF-alpha and the L-arginine/nitric oxide pathway to the vascular dysfunction of SAO shock. Anaesthetized rats, subjected to total occlusion of the superior mesenteric artery and the coeliac trunk for 45 min developed a severe shock state (SAO shock) resulting in a fatal outcome within 75-90 min after the release of occlusion. Sham operated animals were used as controls. SAO shocked rats had also a marked hypotension and enhanced macrophage and serum levels of TNF-alpha. Furthermore, aortic rings from shocked rats showed a marked hyporeactivity to phenylephrine (PE 1 nM-10 microM) and reduced responsiveness to acetylcholine (ACh 10 nM-10 microM). Endothelium-denuded aortic rings had also a marked hyporeactivity to phenylephrine, which was restored to control values by in vitro administration of NG nitro-L-arginine-methyl ester (L-NAME 10 microM). 3. In vivo administration of cloricromene (2 mg kg-1, i.v.), an inhibitor of TNF-alpha biosynthesis, increased survival, enhanced mean arterial blood pressure and reduced macrophage and serum levels of TNF-alpha. Furthermore, aortic rings from shocked rats treated with cloricromene exhibited a greater contractile response to phenylephrine and improved responsiveness to ACh when compared to aortic rings from vehicle-treated SAO shocked rats. 4. Our results suggest that TNF-alpha alters both endothelial and muscular L-arginine/nitric oxide pathways which in turn produce vascular dysfunction in SAO shock.

Acetylcholine↗