Protective effects of a coumarin derivative in diabetic rats.

PURPOSE: Retinal microvascular cells play a crucial role in the pathogenesis of diabetic retinopathy. The endothelial effects of cloricromene, a novel coumarin derivative, on diabetic retinopathy induced by streptozotocin (STZ) in the rat were investigated. METHODS: Cloricromene (10 mg/kg intraperitoneally) was administered daily in diabetic rats, and 60 days later eyes were enucleated for localization of nitrotyrosine, ICAM-1, VEGF, ZO-1, occludin, claudin-5, and VE-cadherin by immunohistochemical analysis. The effect of treatment was also evaluated by TNFalpha, ICAM-1, VEGF, and eNOS protein levels measurement in the retina with the respective ELISA kits. Blood-retinal barrier (BRB) integrity was also evaluated by Evans blue. RESULTS: Increased amounts of cytokines, adhesion molecule, and nitric oxide synthase were observed in retina. Cloricromene treatment significantly lowered retinal TNFalpha, ICAM-1, VEGF, and eNOS. Furthermore, immunohistochemical analysis for VEGF, ICAM-1, nitrotyrosine (a marker of peroxynitrite), and tight junctions revealed positive staining in the retina from STZ-treated rats. The degree of staining for VEGF, ICAM-1, nitrotyrosine, and tight junctions was markedly reduced in tissue sections obtained from diabetic rats treated with cloricromene. Treatment with cloricromene suppressed diabetes-related BRB breakdown by 45%. CONCLUSIONS: This study provides the first evidence that the new coumarin derivative cloricromene attenuates the degree of inflammation preserving the BRB in diabetic rats.

Cloricromene, a coumarine derivative, reduced the development of periodontitis in rats.

Recent studies have demonstrated that cloricromene, a coumarin derivative, exerts protective effects in models of inflammation and shock. Tumour necrosis factor plays a pivotal role in the induction of genes involved in physiological processes, as well as in the response to inflammation. We investigated the effect of cloricromene in a rat model of periodontitis. Periodontitis was induced in rats by placing a 2/0 braided silk ligature around the lower left first molar. At day 8 the gingivomucosal tissue encircling the mandibular first molar was removed for evaluation of tumour necrosis factor production, neutrophil infiltration, tissue permeability, nitrotyrosine formation, poly (ADP-ribose) polymerase activation, radiography and histology. Ligation significantly induced an increased tumour necrosis factor production, neutrophil infiltration and a positive staining for nitrotyrosine formation and poly (ADP-ribose) polymerase activation. Ligation significantly increased Evans blue extravasation in gingivomucosal tissue and alveolar bone erosion as evaluated by radiography analysis. Intraperitonal injection of cloricromene (10 mg/kg daily for 8 days) significantly decreased all of the parameters of inflammation as described above. This suggests that cloricromene treatment, which reduced tumour necrosis factor production, may be of benefit in the treatment of periodontitis.

Cloricromene in endotoxemia: role of NF-kappaB.

In this study we investigated, for the first time in vivo, the effect of cloricromene, a cumarine derivative, on NF-kappaB activation in endotoxin-treated rats. Endotoxemia was induced in male rats by the intravenous injection of Salmonella typhosa lipopolysaccharide (LPS; 2 mg/kg/i.v.). In vivo treatment with cloricromene (2 mg/kg/i.v.) 30 min before lipopolysaccharide administration reversed the LPS-induced loss in tone of the aortic rings, improved their reactivity to phenylephrine, decreased both nitric oxide (NO) and TNF-alpha serum levels by inhibiting LPS-induced inducible NO synthase and TNF-alpha mRNA expression, and interestingly inhibited LPS-induced NF-kappaB activation. Our data suggest that cloricromene protects rats from LPS by blocking LPS-induced NF-kappaB activation, leading to inhibition of NO and TNF-alpha overproduction and thereby reversing the LPS-induced vascular hyporeactivity.

A protective effect of the synthetic coumarine derivative Cloricromene against DNB-colitis in the rat.

Biologic therapies, namely antibodies against tumor necrosis factor-alpha (TNF- alpha) or its receptors, have been recently introduced for the treatment of patients with inflammatory bowel disease (IBD). In the present study the effects of cloricromene, an agent with known antithrombotic actions and with demonstrated anti-TNF- alpha activity were investigated in a rat model of experimental colitis induced with dinitrobenzenesulphonic acid (DNB)/ethanol. We investigated three experimental groups: (i) sham-colitis with vehicle-treatment (controls, n = 6), (ii) colitis with vehicle-treatment (saline, 0.1 ml s.c., daily) (DNB-V, n = 7), (iii) colitis with cloricromene-treatment (10 mg/kg/day s.c.; DNB-C, n = 8). After 7 days, the weight gain, colon wet weight, macroscopic damage score, coagulation parameters, colon mucosal myeloperoxidase activity (MPO), and tissue concentrations of TNF- alpha and of macrophage inhibitory peptide-2 (MIP-2) were assessed. The macroscopic damage scores, colon wet weights, and tissue MIP-2 levels were significantly increased in untreated and in cloricromene-treated rats compared with controls. Cloricromene treatment was associated with a minor body weight loss (p < 0.025) and significantly reduced tissue concentrations of MPO and TNF-alpha (p < 0.02, both). Blood coagulation parameters were not affected by treatment. In the DNB-model treatment with cloricromene effectively reduces tissue levels of TNF- alpha and of myeloperoxidase, whereas MIP-2 concentrations were not influenced. Blood coagulation parameters remained unchanged indicating safety of treatment. Since biological therapies frequently fail to improve disease course of IBD, other therapies with similar targets should be further investigated.

Intradermal injection vs. oral treatment of tinnitus.

Local pharmacological intradermal infiltration is a therapy being used more and more thanks to the positive results achieved, particularly for all those therapies acting on the microcirculation. In trying to better the results obtained with medical therapy for tinnitus sufferers, to assess the effect of a vasoactive drug, the method of administration by the intradermal route, which allows a strengthening of the pharmacological effect, has been added. The present study comprised 120 tinnitus sufferers who underwent intradermal auricle infiltration with a vasoactive drug. The control group includes 115 tinnitus sufferers who underwent systemic vasoactive therapy with the same drug. Forty-five days after beginning intradermal treatment the symptom improved and continued to do so following further infiltrations which patients underwent every 15 days. In the control group we noticed a moderate improvement 45 days after the beginning of oral therapy; thereafter the results reached a plateau by the 60th day. Intradermal vasoactive therapy for idiopathic tinnitus seems to be a new success, which will be an interesting progression in the therapy of this kind of symptom.

Effect of cloricromene on intermittent claudication. A randomized, double-blind, placebo-controlled trial in patients treated with aspirin: effect on claudication distance and quality of life. CRAMPS Investigator Group. Cloricromene Randomized Arteriopathy Multicenter Prospective Study.

The main aim of medical treatment for intermittent claudication (IC) is the reduction of mortality and morbidity from ischemic cardiovascular disease. However, symptomatic treatment with the aim of improving exercise performance and the overall quality of life may also be an important target of the clinical management of patients with intermittent claudication. Cloricromene, a drug with antithrombotic and anti-ischemic activities, has previously shown some promising results in patients with claudication. We have carried out a clinical trial to assess the effect of cloricromene on the claudication distance and on the quality of life of patients with IC chronically treated with aspirin. A total of 159 patients with IC, Stage II (Fontaine), were enrolled in a double-blind, randomized, prospective, multicenter study comparing cloricromene (100 mg orally b.i.d.) or an identical placebo for 6 months. All patients received 160 mg/day aspirin. The primary end-point was the improvement of initial claudication distance (ICD) at 6 months as measured by a standardized treadmill test. The secondary end-points were the absolute claudication distance (ACD) at 6 months, the percentage of patients defined as responders to treatment (improvement of ICD of at least 40%), changes in the ischemic window (IW), quality of life as assessed by the SF-36 questionnaire, and the occurrence of major cardiovascular events. The ICD increased in both treatment groups, with a non-significant difference at 6 months in favor of cloricromene of +12.3 m. The ACD, percentage of responders to treatment and ischemic window also improved in both groups with a slight, non-significant trend in favor of cloricromene. Pretreatment quality of life scores showed only a slight worsening compared with an age-matched, healthy population and did not change upon treatment. A post hoc subgroup analysis showed a significant benefit from cloricromene in patients with an ICD at enrollment higher than the median of the patient population. In conclusion, treatment with cloricromene for 6 months does not significantly improve claudication in patients with Stage II Fontaine peripheral arteriopathy chronically treated with aspirin. An improvement of 40-60 m in the ICD on a standardized treadmill test does not translate into a self-perceived improvement in the quality of life as assessed by the SF-36 questionnaire.

Cloricromene reduces infarct size and alters postischaemic blood flow defects in dog myocardium.

1. The aim of the present investigation was to evaluate the effect of cloricromene on myocardial infarct size, regional myocardial blood flow and neutrophil accumulation in a canine model of ischaemia-reperfusion. 2. Dogs were instrumented to measure blood pressure, left anterior descending (LAD) coronary flow (flow probe) and regional myocardial blood flow (coloured microspheres). Two groups were studied: (i) CLO (n = 8) received an infusion of cloricromene (15 micrograms/kg per min); and (ii) VEH (n = 8) received saline. Infusions began at the onset of ischaemia (60 min) and continued through reperfusion (180 min). 3. Haemodynamic responses were not different between groups. Cloricromene reduced the area of necrosis expressed as a percentage of the area at risk from 35 +/- 3% in the VEH group to 23 +/- 4% in the CLO group (P < 0.05). Regional myocardial blood flow in the ischaemic region was different between groups; VEH dogs showed an early reperfusion hyperaemia followed by a progressive reduction in flow, while CLO dogs exhibited a gradual increase in reflow in the absence of an early hyperaemic response (P < 0.05). Left anterior descending flow was enhanced during the reperfusion period in the CLO group compared with VEH (P < 0.05). Cloricromene reduced polymorphonuclear neutrophil (PMN) infiltration (myeloperuxidase activity) in all myocardial regions when compared with VEH (non-ischaemic zone, 0.34 +/- 0.54 vs 0.05 +/- 0.01 IU/100 mg; ischaemic zone, 2.03 +/- 0.80 vs 0.24 +/- 0.08 IU/100 mg; and necrotic zone, 0.56 +/- 0.04 vs 3.59 +/- 1.09 IU/100 mg for VEH vs CLO groups, respectively; P < 0.01). In a separate in vitro preparation, cloricromene reduced adherence of platelet-activating factor (PAF)-stimulated PMN to canine coronary endothelium. Stimulation of PMN by 100 nmol/L PAF resulted in adherence of 176 +/- 36 compared with 48 +/- 12 cells/mm2 in PAF-stimulated PMN treated with 100 mumol cloricromene (P < 0.001). 4. These data indicate that cloricromene reduces myocardial infarct size in a canine model of ischaemia-reperfusion injury. Postischaemic blood flow patterns are significantly different in cloricromene-treated dogs. Cloricromene-mediated reductions in infarct size, neutrophil accumulation and adherence may play a role in this effect.

Effects of cloricromene on the levels of endothelin and on the microcirculatory function in peripheral atherosclerotic arteriopathies.

The effects of cloricromene on plasma endothelin-1 (ET-1) levels and on microcirculatory function in 9 patients with peripheral atherosclerotic arteriopathy (PAA) and in healthy control subjects were studied. ET-1 levels and microcirculatory function were evaluated both under basal conditions and 30, 60, and 90 min after acute administration of cloricromene (30 mg i.v.). PAA patients had significantly increased levels of ET-1 and impaired vascular parameters (studied by means of Winsor's Index, Gosling's Index, postischemic perfusion index and recovery time) when compared to control subjects. The acute administration of cloricromene (30 mg i.v.) did not change plasma ET-1 both in control subjects and in patients with PAA. In contrast, cloricromene produced a significant improvement in the postischemic perfusion index and in recovery time in arteriopathic patients. Control subjects and patients with PAA also underwent a cold pressor test (CPT) under basal conditions and (72 h later) 30 min after an acute intravenous administration of cloricromene (30 mg i.v.). CPT caused a higher increase in ET-1 in the patients with PAA compared to the control group, and a reduction in the vascular flow at the femoral level, while the pretreatment with cloricromene prevented both the increase in the levels of ET-1 and the reduction of the femoral vascular flow observed after the cold stimulus in patients with PAA. Our data show that cloricromene, besides ameliorating the microcirculatory function, is able to interfere with dynamic mechanisms, such as those induced by the CPT, capable of stimulating the release of ET-1 at the vascular level.

Multiple actions of the coumarine derivative cloricromene and its protective effects on ischemic brain injury.

The effects of different doses (0.25, 0.5, 1 and 2 mg/kg i.p.) of cloricromene, a coumarine derivative, have been investigated on brain malondialdehyde levels, brain edema, myeloperoxidase activity, survival, locomotor hyperactivity and hippocampal neuronal loss following transient cerebral ischemia induced by temporary bilateral carotid occlusion in the Mongolian gerbil. Cloricromene reduced brain lipid peroxidation, measured through the evaluation of malondialdehyde (-82.9% with the highest dose), and the formation of post-ischemic brain edema, evaluated by water content. The increase in myeloperoxidase activity observed in the hippocampus of postischemic animals was also reduced: 0.7 +/- 0.3 U x 10(-3) vs. 3.3 +/- 0.3 U x 10(-3)/g tissue. The same treatment increased survival and reduced hyperactivity linked to neurodegeneration induced by cerebral ischemia and reperfusion. Histological observations of the pyramidal layer of CA1 showed a reduction of neuronal loss in animals that received the drug before occlusion but not in those that were treated after the occlusion. These results show that cloricromene, a drug with multiple actions, improves brain injury induced by transient cerebral ischemia.

Functional depression of isolated perfused rat heart mediated by activated leukocytes: protective effect of cloricromene.

Langendorff rat heart preparations were perfused with suspensions of human leukocytes containing approximately 65% polymorphonuclear cells (PMN). The cells were either unstimulated or activated with 1.6 x 10(-8) phorbol 12-myristate 13-acetate (PMA). Left ventricular developed pressure (LVDP), coronary flow (CF), and heart rate (HR) were recorded during PMN infusion (10 min) and for the recovery period (30 min). PMN were also pretreated with cloricromene (CLO 10-50 microM), a drug that inhibits platelet aggregation and PMN adhesion to endothelial cells (EC). Infusion of unstimulated cells did not affect cardiac function. Infusion of activated cells caused CF reduction (-44 +/- 4% at end of infusion; -24 +/- 4% at end of recovery, expressed as percentage of variation vs. basal value), LVDP decrease (-44 +/- 5% at end of infusion, -26 +/- 6% at end of recovery) endothelial damage, and leukocyte accumulation in heart as compared with hearts infused with unstimulated PMN and sham hearts. PMN accumulation was quantified as myeloperoxidase (MPO) activity (260 +/- 35, 39 +/- 6, 19 +/- 1 U/g, respectively). Superoxide dismutase (SOD 600 U/ml), catalase (2,200 U/ml), thiourea (10 mM) added to PMN suspension blunted CF decrease but not LVDP reduction and MPO increase. CLO (25-50 microM) pretreatment inhibited PMN accumulation, LVDP, and CF reduction by approximately 50%. These data suggest a role of leukocyte activation in the genesis of heart damage and raise the possibility of a pharmacologic intervention with drugs such as CLO that can interfere with this process.

No effect of cloricromen on some coagulation parameters in patients with ischaemic cerebrovascular disease.

Cloricromen is a new drug that inhibits platelet aggregation in man and in experimental thrombosis. Twenty patients with a history of atherothrombotic stroke received cloricromen (100 mg, twice daily) for 30 days in order to evaluate its effects on plasma fibrinogen, antithrombin III, and other variables of the haemostatic system. A statistically significant decrease in the prothrombin time (P < 0.01) was found only after 30 days of therapy. This decrease was transient and disappeared 15 days after the end of treatment. No statistically significant changes in plasma fibrinogen levels, antithrombin III, partial thromboplastin time, or platelet count were observed compared with baseline values. No side-effects were reported. This study did not reveal an effect of cloricromen on coagulative variables in patients with cerebrovascular occlusive disease.

Beneficial effects of cloricromene in ischemic reperfused myocardium.

Cloricromene (Clo) has been used to prevent myocardial damage after transient occlusion of the circumflex coronary artery (Cx). Twenty rabbits were injected for 4 days with a single dose of Clo (0.25 mg/kg i.v.) or placebo. On the 5th day, the Cx was occluded, and Clo (6.4 micrograms/kg/min) or placebo was continuously infused. After 50 min, the occlusion was removed and after 20 min of reperfusion, the rabbits were sacrificed. In the placebo group, all rabbits showed marked ST segment changes and severe ischemic arrhythmias (6/10 animals). In 5 of them, ventricular fibrillation was followed by death. In the Clo group smaller ST segment elevations were observed, and in 2 rabbits ventricular fibrillation spontaneously reversed as did ST segment elevations. A significant reduction of the necrotic area was also observed in the Clo group by postmortem examination.

Dissociation of the anti-ischaemic effects of cloricromene from its anti-platelet activity.

1. Cloricromene is a non-anticoagulant coumarin derivative with anti-platelet and anti-leukocyte properties, which has beneficial effects in various models of ischaemia and shock. 2. We have assessed the effects of cloricromene on (a) ex vivo platelet aggregation, and (b) infarct size using a model of myocardial ischaemia in the anaesthetized rabbit. 3. Cloricromene (1-1000 micrograms kg-1 min-1 for 15 min) induced a dose-dependent inhibition of ex vivo platelet aggregation, causing only a minimal increase in heart rate and no change in mean arterial blood pressure. The inhibitory activity was considerably stronger when platelet aggregation was induced by collagen than by ADP. 4. Cloricromene inhibited ex vivo platelet aggregation in rabbits pretreated with indomethacin (5 mg kg-1) and this inhibition persisted for 30-60 min. 5. The model of myocardial ischaemia involved 1 h occlusion of the first antero-lateral branch of the left coronary artery followed by 2 h of reperfusion. Infusion of cloricromene (30 or 300 micrograms kg-1 min-1), ibuprofen (80 micrograms kg-1 min-1) or vehicle began 15 min prior to occlusion, and continued throughout the experiment. 6. While area at risk was similar for all groups studied, cloricromene (30 or 300 micrograms kg-1 min-1) or ibuprofen caused a reduction in infarct size, and decreased myeloperoxidase activity in the tissue of the infarcted myocardium. 7. Cloricromene at 300 micrograms kg-1 min-1 also reduced the occlusion-induced elevation of the ST-segment of the rabbit electrocardiogram, and inhibited platelet aggregation ex vivo. Ibuprofen or cloricromene at 30 fg kg-1 min-1 had no effect on either the ST-elevation or platelet reactivity.8. Thus, cloricromene exhibits a cardioprotective activity via an inhibition of leukocyte infiltration, in the presence (300 microg kg-l min-1) or absence (30 microg kg-1 min-1) of inhibition of platelet activity ex vivo.The anti-aggregatory activity of cloricromene acts via a mechanism that is either different from, or in addition to, inhibition of cyclo-oxygenase, and is of long duration.

[Tumor necrosis factor in myocardial ischemia and reperfusion]. / Tumor necrosis factor nell'ischemia e riperfusione miocardica.

The role of tumor necrosis factor (TNF-alpha) was investigated in an anaesthetized rat model of coronary artery ligation (60 min) followed by reperfusion (60 min; MI/R). Sham operated rats were used as controls (Sham MI/R). Myocardial necrosis, myocardial myeloperoxidase activity (MPO; investigated as an index of leukocyte adhesion and accumulation), serum creatinphosphokinase (CPK) activity and serum and macrophage TNF-alpha were studied. Ischemia and reperfusion produced a marked myocardial injury, with enhancement of serum CPK levels and myocardial MPO activity in the area at risk and in the necrotic area. Furthermore, serum TNF-alpha was undetectable during the occlusion period, but increased significantly after release of the coronary artery. At the end of reperfusion, macrophage TNF-alpha was also enhanced. A passive immunization with a hyperimmune serum containing antibodies against murine TNF-alpha or administration of an inhibitor of TNF-alpha synthesis, such as cloricromene, significantly lowered myocardial necrosis, reduced the increase in serum CPK and decreased MPO activity in the area at risk and in the necrotic area. Finally, the administration of the specific anti-TNF-alpha antibodies neutralized the serum levels of TNF-alpha and the injection of cloricromene reduced both serum and macrophage TNF-alpha. These data are consistent with an involvement of TNF-alpha in myocardial ischemia-reperfusion injury and suggest that drugs capable of reducing TNF-alpha might represent a novel therapeutic approach to the treatment of myocardial reperfusion injury.

The effect of cloricromene, a coumarine derivative, on leukocyte accumulation, myocardial necrosis and TNF-alpha production in myocardial ischaemia-reperfusion injury.

The effects of cloricromene, a coumarine derivative, were studied in an anaesthetized rat model of coronary artery ligation (60 min) followed by reperfusion (60 min; MI/R). Sham operated rats were used as controls (Sham MI/R). Myocardial ischaemia-reperfusion injury produced a marked myocardial injury (necrotic area/area-at-risk = 68 +/- 4%; necrotic area/total area = 48 +/- 3%) high serum creatinphosphokinase activity (Sham MI/R = 29 +/- 8 U/ml; MI/R = 205 +/- 11 U/ml) and elevated myocardial myeloperoxidase activity (investigated as an index of leukocyte adhesion and accumulation), in the area-at-risk (6.3 +/- 0.2 U x 10(-3)/g tissue) and in necrotic area (6.5 +/- 0.5 U x 10(-3)/g tissue). Furthermore, serum TNF-alpha was undetectable during the occlusion period, but upon the release of the coronary artery significantly increased. At the end of reperfusion, macrophage TNF-alpha was also enhanced. The administration of cloricromene (2 mg/kg, 5 minutes after the onset of reperfusion) significantly reduced myocardial injury (necrotic area/area-at-risk 30 +/- 1.3%; necrotic area/total area = 25 +/- 1.5) blunted the increase in serum creatinphosphokinase activity (92 +/- 5 U/ml) and lowered myeloperoxidase activity in area-at-risk (2.5 +/- 0.2 U x 10(-3)/g tissue) and in necrotic area (2.2 +/- 0.3 U x 10(-3)/g tissue) and decreased the serum and macrophage levels of TNF-alpha. These data indicate that cloricromene exerts beneficial effects on myocardial ischaemia/reperfusion injury. Finally, since we measured increased serum levels of TNF-alpha that were blunted by the cloricromene treatment, our data are consistent with an involvement of TNF-alpha in the reperfusion injury induced by myocardial ischaemia.

Cloricromene, a coumarine derivative, protects against lethal endotoxin shock in rats.

Endotoxin shock was induced in male rats by an intravenous (i.v.) injection of Salmonella enteriditis lipopolysaccharide (LPS; 20 mg/kg i.v.). Survival rate, macrophage and serum tumor necrosis factor (TNF-alpha), mean arterial blood pressure (MAP) and white blood cell count were then evaluated. Furthermore the in vitro effect of cloricromene on peritoneal macrophage phagocytosis and TNF-alpha release by primed peritoneal macrophages was investigated. LPS administration caused animal death (0% survival 24 h after endotoxin challenge), hypotension, marked leukopenia and increased the levels of TNF-alpha in both serum and macrophage supernatants. Cloricromene administration (0.5, 1 and 2 mg/kg i.v. 15 min after endotoxin) protected against LPS-induced lethality (100% survival rate 24 h after endotoxin challenge), reverted LPS-induced hypotension and leukopenia, and decreased TNF-alpha in both serum and macrophage supernatants. Finally, cloricromene, added in vitro to peritoneal macrophages collected from endotoxin-treated rats increased macrophage phagocytosis and reduced TNF-alpha formation by activated mononuclear phagocytes. Our data suggest that cloricromene increases survival rate in endotoxin shock through an inhibition of TNF-alpha production.

Cloricromene improves survival rate and peritoneal macrophage function in splanchnic artery occlusion shock in rats.

Splanchnic artery occlusion (SAO) shock, induced by a transient occlusion of splanchnic arteries for 45 min, was performed in male rats, treated with vehicle or cloricromene, a coumarin derivative, 15 min before surgery. Survival rate, plasma levels of myocardial depressant factor (MDF), macrophage phagocytosis and killing of Candida albicans, and thromboxane B2 (TxB2) synthesis by peritoneal macrophages were evaluated. Of the SAO-shocked animals, 10% survived for 6 hr after the release of the occlusion of the splanchnic arteries, whereas none of the sham-shocked rats died. Peritoneal macrophages of shocked animals exhibited decreased phagocytosis (24.7 +/- 2.7%) and killing (8.0 +/- 2.1%) and increased TxB2 levels (3.23 +/- 0.27 ng/ml) with respect to those collected from sham-shocked animals (phagocytosis 48.8 +/- 3.0%; killing 16.5 +/- 2.4%; TxB2 0.30 +/- 0.18 ng/ml). MDF was also increased (114.3 +/- 21.5 U/ml) compared with sham-shocked animals (31.5 +/- 3.7 U/ml). Cloricromene, given intravenously (i.v.) at doses of 1, 2, and 4 mg/kg, significantly increased survival rate and lowered MDF in shocked rats. Lower doses (0.25 and 0.5 mg/kg/i.v.) were without effect. Doses that were able to reduce mortality partially reverted shock-induced macrophage impairment of phagocytosis, killing of C. albicans, and TxB2 synthesis. In addition, cloricromene (5, 10, and 25 microM) added in vitro to peritoneal macrophages, collected from shocked rats, significantly enhanced their phagocytic activity depressed by shock.

Normothermic ischemic cardiac arrest and reperfusion of the isolated working rat heart: effect of carbocromene pretreatment on functional and metabolic recovery.

Normothermic Ischemic Cardiac Arrest and Reperfusion of the Isolated Working Rat Heart: Effect of Carbocromene Pretreatment on Functional and Metabolic Recovery. This paper describes the effect of carbocromene pretreatment on the functional recovery of the isolated rat heart submitted to ischemic cardiac arrest and reperfused. In a previous study we showed that hearts isolated from rats which had been pretreated for 8 days with a daily oral administration of carbocromene at 15 mg/kg body weight, exhibit higher mechanical performances (aortic output, coronary flow, cardiac work) than hearts isolated from untreated animals. This was associated with a greater tissue content of high energy phosphates and glycogen. In the present work, carbocromene-pretreated hearts are submitted to 30 minutes of normothermic no-flow ischemia after being arrested by a 2 min high potassium, substrate-free perfusion, containing 2 mg/l carbocromene (cardioplegic solution). After reperfusion, post-ischemic recovery of function is significantly better in treated hearts as compared to control untreated preparations submitted to a similar protocol. Although no significant difference can be demonstrated in the metabolic status of either groups of preparations after 30 min of reperfusion, lactate dehydrogenase release, taken as an index of myocardial cell damage, is significantly reduced in the carbocromene-treated group. In view of these results it is suggested that carbocromene pretreatment and/or the addition of carbocromene to cardioplegic solutions could be beneficial in improving functional recovery after temporary ischemic cardiac arrest.

Protection by carbocromene and molsidomine against arrhythmias occurring during coronary artery occlusion and reperfusion in dogs.

We studied the effects of carbocromene (4 mg/kg plus 40 micrograms/kg/min i.v.) and molsidomine (0.1 mg/kg plus 2 micrograms/kg/min i.v.) on arrhythmias occurring during 90-min occlusion and 30-min reperfusion of the left anterior descending coronary artery in anesthetized dogs. Both drugs reduced the incidence of left ventricular (LV) premature depolarization during ligation (39% after carbocromene and 33% after molsidomine vs. 80% in controls; both p less than 0.05) and tachycardia (44% after carbocromene and 38% after molsidomine vs. 85% in controls; p less than 0.05). During reperfusion, the incidence of LV fibrillation was reduced in the carbocromene- (6 vs. 38% in controls; p less than 0.05) and molsidomine-treated dogs (10 vs. 38% in controls; p less than 0.05). The high incidence of ectopic activity and the ST segment elevation occurring after coronary ligation in control animals were prevented by both drugs. The hemodynamic deterioration after coronary occlusion, i.e., increase in blood pressure, LV systolic and end-diastolic pressures, LV dP/dtmax, and tachycardia observed in controls, was prevented by carbocromene. Molsidomine reduced blood pressure and LV pressure by 18 and 27% (p less than 0.05), respectively, during coronary occlusion. During reperfusion, no hemodynamic alterations occurred in the drug-treated animals. We conclude that carbocromene reduced the electrophysiologic consequences of acute ischemia by hemodynamic and anti-ischemic effects on heart metabolism. Molsidomine protected the jeopardized heart by a similar attenuation of hemodynamic derangement after coronary occlusion and perhaps by influencing prostanoid release from the ischemic myocardium.