Transcellular synthesis of Cys-LT: from isolated cells to complex organ system.
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Animals↗
Biomedical subjects
F Berti
Publications and source records attributed to F Berti.
Modulation of leukocyte-endothelial cell interaction and leukotriene dependent vasoconstriction by prostacyclin mimetics in the isolated rabbit heart.
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Animals↗
Effects of warm ischemia on valve endothelium.
BACKGROUND: This study investigates the time-dependent resistance of the endothelium of porcine aortic and pulmonary valves to different periods of warm ischemia (WIT). METHODS: Twenty-five 9-month-old swine were divided after death into five groups of WIT (0, 6, 12, 24, and 36 hours). Aortic and pulmonary valves were removed and a total of 15 aortic and 15 pulmonary valve specimens were obtained for each WIT interval. Valves were then examined for (1) their viability rate by the trypan blue dye exclusion method at light microscopy (percent of viability compared with 0 hours of WIT); (2) ultrastructural signs of irreversible or reversible ischemic damage by transmission electron microscopy (cell disruption, dilation of endoplasmic reticulum, cytoplasmic edema, nuclear and mitochondrial changes); (3) endothelial function by pharmacologic evaluation of both the endothelial-releasing capacity of prostacyclin and the endothelial-dependent dynamic responses to relaxing (acetylcholine from 1 x 10(-10) mol/L to 1 x 10(-4) mol/L) in aortic and pulmonary valve segments precontracted with norepinephrine (1 x 10(-6) mol/L) and contracting (NG-monomethyl-L-arginine, 1 x 10(-4) mol/L) drugs. RESULTS: Our results showed an endothelial progressive time-dependent ischemic injury, which reached significance after 12 hours of exposure. Viability and functional data indicated that 6 hours of WIT only provoked slight endothelial damage (p > 0.05 respect to time 0 hours), with signs at transmission electron microscopy consistent with a reversible injury. At 12 hours of exposure, we observed a significant reduction (p < 0.05) with respect to time 0 of the viability rate of prostacyclin production and of the endothelium-dependent dynamic responses to acetylcholine and NG-monomethyl-L-arginine. These functional impairments, although significant, were not consistent, however, with a complete loss of viability. Transmission electron microscopic observations confirmed the appearance of signs of irreversible injury; nevertheless, some elements were found to be well preserved or presented reversible damage. After 24 hours of WIT, ultrastructural and functional data were consistent with a dramatic decrease compared with controls in endothelial viability and functions (p < 0.01). Finally, after 36 hours of WIT, there was a subtotal loss of viability, of functions (p < 0.001) and, at transmission electron microscopic observations, of the endothelial layer of the valves. CONCLUSIONS: Our data show that the endothelial cells are resistant to short periods of WIT (up to 6 hours), and suggest that these cells can endure longer exposures, up to 12 hours of warm ischemia. Periods of 24 and 36 hours of WIT provoke progressive irreversible damage.
Acetylcholine↗
Incidence of risk of thromboembolism during treatment high-grade gliomas: a prospective study.
A prospective study of a series of 77 patients on adjuvant radiochemotherapy following surgery for high-grade gliomas was conducted to evaluate the risk of deep vein thrombosis and identify risk factors. We found a 20.8% risk of deep vein thrombosis at 12 months (standard error = 4.8%) and a 31.7% risk (standard error = 7.4%) at 24 months (Kaplan-Meier method). Twenty patients (26%) developed deep vein thrombosis with a maximum incidence within the first 7 months after surgery when chemotherapy was still being administered, often with corticosteroids. The risk factors identified were histology (glioblastoma versus anaplastic astrocytoma, P = 0.032, log rank test; 0.0485 L-ratio) and the presence of paresis (P = 0.010, log rank test; 0.0161 L-ratio). A borderline tendency was found for an association between the deep vein thrombosis site and the side of paresis (P = 0.103, Fisher's exact test). Four patients (5%) had massive pulmonary embolism, which was fatal in 3 (4%).
Adolescent↗
Nitric oxide modulation of transcellular biosynthesis of cys-leukotrienes in rabbit leukocyte-perfused heart.
1. We have studied the role of nitric oxide (NO) in the regulation of the transcellular biosynthesis of sulphidopeptide leukotrienes (cys-LT) generated upon neutrophil-vascular wall interactions and their functional consequences, in the spontaneously beating, cell-perfused, heart of the rabbit. 2. Hearts were perfused under recirculating conditions (50 ml) with 5 x 10(6) purified human neutrophils (PMNL), and challenged with 0.5 microM A-23187 for 30 min. Coronary perfusion pressure (CPP) and left-ventricular end-diastolic pressure (LVEDP) were monitored. Cys-LT formation was measured by reversed phase high performance liquid chromatography (h.p.l.c.) and u.v. spectral analysis. Myeloperoxidase (MPO) enzyme activity, assayed in aliquots of the recirculating buffer, was used as a marker of PMNL, adhesion to the coronary endothelium. 3. Basal CPP and LVEDP values averaged 45 +/- 1.4 mmHg and 5 +/- 0.1 mmHg, respectively; A-23187 triggered an increase in CPP (134 +/- 9 mmHg, at 30 min) which was significantly attenuated by pretreatment with L-arginine, 100 microM (90 +/- 3 mmHg, at 30 min). Pretreatment with NG-monomethyl-L-arginine, 10 microM (L-NMMA), induced a marked increase in CPP (290 +/- 40 mmHg, at 20 min) and in LVEDP (47 +/- 16 mmHg), so pronounced that it caused cardiac arrest in systole in 5 out of 6 hearts and these were prevented by L-arginine, 100 microM, (CPP 115 +/- 10 mmHg, LVEDP 6 +/- 1.1 mmHg, at 30 min). 4. The increase in CPP was accompanied by the release of cys-LT in the circulating buffer, which was reduced significantly by L-arginine. Pretreatment with L-NMMA, caused a marked rise in cys-LT concentrations which was prevented by L-arginine. 5. Neither L-arginine nor L-NMMA affected directly the A-23187-induced arachidonic acid (AA) metabolism in isolated PMNL alone. 6. Pretreatment with L-NMMA caused a prompt drop in myeloperoxidase (MPO), activity, suggesting rapid adhesion of PMNL to the coronary wall; this effect was significantly blunted by L-arginine. 7. This study suggests that NO provides cardioprotection in an organ model of transcellular metabolism of cys-LT by preventing PMNL adhesion to the coronary intima.
Animals↗
Phase II trial with BCNU plus alpha-interferon in patients with recurrent high-grade gliomas.
A Phase II study with a combination of BCNU and alpha-interferon (IFN) was conducted in patients with high-grade glioma recurrent after surgery and radiation treatment in order to investigate tumor control and toxicity. Twenty-one non-chemotherapy pretreated patients were administered 6 MU alpha-IFN in a 2-h infusion followed by 150 mg/m2 BCNU i.v. on day 1. Three MU alpha-IFN were subsequently administered subcutaneously on alternating days three times a week, until recycling of the whole procedure on day 42. Among 21 patients, partial remission was obtained in 7 (33%; 95% CI = 15-57) and stable disease in 6 (29%; CI = 11-52); overall Kaplan-Meier median time to progression (TTP) was 4.5 months (CI = 4-9) and the overall median survival time (MST) was 7 months (CI = 5-13). In patients who underwent surgical redebulking prior to chemotherapy, TTP and MST were 9 (CI = 7-14) and 15 months (CI = 11.0-39.0); in patients who were not operated on again before chemotherapy, these values were 4 (CI = 2-5; log rank test, p = 0.0026) and 5.5 months (CI = 4-7; log rank test, p = 0.0012) respectively. The results of this regimen in relapsing patients, especially following surgical redebulking, are encouraging; toxicity is acceptable, and further studies on combined alpha-IFN and multiple-agent chemotherapy are warranted.
Adult↗
[Goodpasture's disease or syndrome? Apropos of a case].
Goodpasture's disease is characterized by lung haemorrhage, associated with glomerulus basement membrane antibody glomerulonephritis, and circulating basement membrane antibody. Other diseases (Wegener, LES, arteritis) may have the same kidney and lung involvement. The Authors present a clinical case of rapidly progressive renal failure where renal biopsy showed an extensive extracapillary proliferative glomerulonephritis with linear deposits of antibody in the basement membrane, similar to Goodpasture's disease, with following lung involvement, but without hemoptysis and in absence of circulating antiglomerular basement membrane antibody. The Authors think it could be a case of Goodpasture's disease, even if it did not show the above-mentioned symptoms, whether out of the characteristic clinical course or the exclusion of all the other diseases. The Authors believe that the absence of circulating basement membrane antibody could be due to their sediment in the target organs and suggest a revision of the standards required for the Goodpasture's disease diagnosis.
Anti-Glomerular Basement Membrane Disease↗
Influence of acetylcysteine on aggravation of ischemic damage in ex vivo hearts of rats exposed to hyperbaric oxygen.
Rats were exposed to hyperbaric oxygen (HBO = 100% oxygen; 2.5 atmospheres absolute pressure) for 6 h. Isovolumic left heart preparations from these animals were subjected to global low flow-ischemia (perfusion rate from 12 ml/min to 2 ml/min for 40 min) and reperfusion. Hearts from rats not exposed to HBO underwent the same ischemic-reperfusion procedure (controls). As compared to control, HBO treatment caused in ex vivo hearts a significant aggravation of cardiac ischemic picture as indicated by a marked increase in left ventricular end diastolic pressure (LVEDP) and reduced post ischemic left ventricular developed pressure (LVDP). At the end of the ischemic and reperfusion periods LVEDP values were 6.8 (p < 0.001) and 8 (p < 0.001) times higher than the corresponding control values. Moreover, LVDP and coronary perfusion pressure (CPP) values were decreased (2.8 times; p < 0.001) and increased (56%; p < 0.001), respectively, as compared to control preparations. These events were also associated with a considerable impairment of the cardiac tissue to generate 6-keto-PGF1 alpha. Treatments of rats with different doses of acetylcysteine (N-acetylcysteine, CAS 616-91-1, NAC; 0.25-0.5-1 g/kg p.o.) before HBO displayed a clear-cut and dose-related protective activity in hearts subjected to ischemia-reperfusion. Also the generating capacity of 6-keto-PGF1 alpha from these hearts were restored according to the dose of NAC employed. When aortic rings from rats exposed to HBO were considered, they showed a reduced capacity to release 6-keto-PGF1 alpha and an increased sensitivity to endothelin-1. At the same time, the relaxant activity of acetylcholine in these tissues was almost lost. Again, NAC treatment of the animals before HBO restored in a dose-dependent way the capacity of the aortic rings to generate 6-keto-PGF1 alpha. This event was paralleled by normalized responses of the preparations to endothelin-1 and acetylcholine. Taken together these results clearly indicate that acute HBO treatment of the rats markedly aggravates the ischemic-reperfusion damage in ex vivo hearts. This event is coupled with a compromised integrity of cardiac and extracardiac endothelial cell functions. The protective activity of NAC observed in this study once more emphasises its therapeutic role in increasing antioxidant defence mechanisms.
Acetylcysteine↗
Hexarelin, a growth hormone-releasing peptide, discloses protectant activity against cardiovascular damage in rats with isolated growth hormone deficiency.
The ability of hexarelin, a recently synthesized hexapeptide with a remarkable growth hormone (GH)-releasing activity, to reverse signs of cardiovascular dysfunction in GH-deficient animals was studied in young male rats made GH deficient by the administration of an anti-GH-releasing hormone serum (GHRH-Ab) for 20 days. Heart preparations from GHRH-Ab treated rats, subjected to low-flow ischemia and reperfusion, showed: a progressive increase of left ventricular end-diastolic pressure during the ischemic period and a poor recovery of contractility at reperfusion as compared to control hearts; a decreased rate of formation of 6-keto-PGF1 alpha, the stable metabolite of prostacyclin, in perfusates of both preischemic and reperfusion period; an increased vasopressor activity of angiotensin II on the coronary vasculature. The endothelium-dependent relaxing function in GH-deficient rats was also evaluated in aortic ring preparations, which showed: a decreased rate of formation of 6-keto-PGF1 alpha, an hyperreactivity to endothelin-1, a markedly reduced vasopressor response to NG-monomethyl-L-arginine (the nitric oxide synthase inhibitor) and a decreased vasodilator response to acetylcholine of precontracted aortic tissue. Hexarelin (80 micrograms/kg, s.c. twice daily), administered for 15 days to GHRH-Ab-treated rats, fully restored the somatotropic function and reversed all the signs of cardiac and endothelial dysfunction. In fact, in heart preparations from rats treated with hexarelin the trend of the ischemic damage was similar to that observed in control rats and both the rate of formation of 6-keto-PGF1 alpha and the vasopressor activity of angiotensin II were reverted to control levels. Furthermore, all the parameters of endothelial function were in the normal range. These results indicate that GH deficiency in rats is responsible for an impairment of cardiac function that is associated with a damage of the endothelium-dependent relaxing function not limited to coronary vessels but widespread in the circulation. These alterations are fully reverted by an in vivo treatment with hexarelin.
Animals↗
Worsening of ischemic damage in hearts from rats with selective growth hormone deficiency.
The effects of growth hormone (GH) deficiency on cardiac function were studied in young male rats administered an anti-GH-releasing hormone (GHRH) serum from postnatal day 20 to 40. Dependence of heart abnormalities on GH deficiency was ascertained by giving a group of anti-GHRH serum-treated rats GH replacement therapy. Heart preparations from anti-GHRH serum-treated rats, undergoing low-flow ischemia, showed a progressive increase in left ventricular end-diastolic pressure with poor recovery of mechanical activity and increased coronary perfusion pressure upon reperfusion. Hearts from anti-GHRH serum + GH-treated rats, undergoing global reduction to the flow, showed only a minimal increase of left ventricular end-diastolic pressure and, upon reperfusion, cardiac mechanical activity recovered almost completely. Similar findings were also observed in heart preparations from control (normal rabbit serum-treated) rats. Infusion of acetylcholine (10(-6) M) into heart preparations in the preischemic period increased coronary perfusion pressure values more markedly in hearts from normal rabbit serum- and anti-GHRH serum + GH-treated rats than in those from anti-GHRH serum-treated rats. These results indicate that selective GH deficiency in young male rats renders the heart more sensitive to ischemic damage and leads to an impairment of cardiac muscarinic receptor function.
Acetylcholine↗
Morphological and functional changes of coronary vasculature caused by transcellular biosynthesis of sulfidopeptide leukotrienes in isolated heart of rabbit.
Morphological and functional modifications occurring in Langendorff rabbit heart preparations perfused with purified human leukocytes (PMNL), as an organ model of sulfidopeptide-leukotrienes (sLT) transcellular biosynthesis, were studied. Coronary perfusion pressure (CPP), monitored as an index of coronary vasospasm, increased by 295% after challenge with the Ca(2+)-ionophore A-23187 (0.5 micromol/L) for 30', accompanied by a significant formation of sLT. Increase in CPP was prevented by PMNL pretreatment with the 5-lipoxygenase inhibitor MK-886 (1 micromol/L) or by heart pretreatment with LTD4-receptor antagonist SKF 104353, indicating a pivotal role of PMNL-derived 5-lipoxygenase (5-LO) products in the observed functional modifications. Similar effects were obtained using granulocyte macrophage-colony stimulating factor-primed PMNL challenged with the tripeptide n-formyl-methionyl-leucyl-phenylalanine. Scanning electron microscopy (SEM) of coronary arteries showed craters on the vessel luminal surface, PMNL adhering to endothelial cells (EC), increased number of microvilli on EC, presence of nonviable, desquamating, fusiform EC. SEM and transmission electron microscopy of myocardial microvessels, showed presence of perivascular and intermuscle edema, presence of activated PMNL and decreased number of patent microvessels. These morphological alterations were significantly blunted by MK-886 or SKF 104353. These data provide evidence of close interaction between PMNL and myocardial EC, resulting in enhanced sLT formation via transcellular biosynthesis, originating from transfer of PMNL-derived LTA4 to EC. These potent proinflammatory autacoids are responsible for coronary vasospasm and the morphological alternations observed.
Animals↗
Early chemotherapy and concurrent radio-chemotherapy in high grade glioma.
PURPOSE: The poor results from treatment of high grade glioma prompted us to explore new protocols involving concurrent radio-chemotherapy. Our primary objective was to evaluate the feasibility of very early postoperative chemotherapy with BCNU, concurrent radio-chemotherapy with carboplatin and teniposide, and post-radiotherapy BCNU. Our secondary objectives were to evaluate time to progression, and overall survival. PATIENTS AND METHODS: We treated 24 newly diagnosed patients (pts) with BCNU 150 mg/m2 seven days after surgery. Thirty days later, we started radiotherapy, 1.8 to 2 Gy/day for 5 days a week on limited fields up to 60 Gy, and concurrent chemotherapy with carboplatin 250 mg/m2 on days 1, 22, and 43, and teniposide 50 mg/m2 on days 1, 2, 3, 22, 23, 24, 43, 44 and 45. Two cycles of 150 mg/m2 BCNU were then given at 30 and 70 days, respectively, after the end of the radio-chemotherapy course. Therapy was then suspended, but if disease progression was evident, treatment was resumed with drugs that had not been previously employed. Surgical reintervention was not routinely considered. RESULTS: Following radio-chemotherapy treatment in the 24 pts evaluable for response, we observed partial remissions in 8 cases (33%) and stable disease in 12 (50%). Actuarial estimates of progression free survival (PFS) were 33 weeks, with 56 wks for anaplastic astrocytoma and 31 weeks for glioblastoma. Median survival time (MST) of all pts was 58 weeks; 51 weeks for glioblastoma and was not reached for anaplastic astrocytoma. This regimen was feasible. Of 144 planned cycles, 139 were delivered, and among these only in 13 and 9 cycles the doses were reduced by 75 and 50%, respectively. We did not observe any gastrointestinal toxicity. Grade 2 hematological toxicity occurred in 25% of pts. grade 3 in 4% and neurological toxicity in 3% of the pts during BCNU delivery, probably due to a sharp increase in intracranial pressure. CONCLUSION: Early chemotherapy, concurrent chemo-radiotherapy and brief post-radio-therapy chemotherapy are feasible and well tolerated. The objective response and disease stabilization rates appear similar to previous experiences.
Adult↗
Protective activity of ketoprofen lysine salt against the pulmonary effects induced by bradykinin in guinea-pigs.
We investigated the capacity of ketoprofen lysine salt (KLS) to counteract the pulmonary effects of some mediators of airway inflammation. The protective effect of KLS and its R-isomer against bradykinin (BK) induced plasma extravasation in the airways and bronchoconstriction was evaluated in anaesthetized guinea-pigs, in parallel with the capacity of KLS to inhibit the production of thromboxane A2 (TXA2). Moreover, we studied the ability of KLS to modulate leukotriene C4 (LTC4) and acetylcholine (ACH) induced bronchoconstriction and the associated production of TXA2. Nimesulide (NIM) was used as the reference compound. KLS dose-dependently inhibited the bronchoconstriction and the associated production of TXA2 induced by BK, with closely related ID50 values of 31.2 and 34.0 micrograms/kg i.v., respectively. The protection was evident 10 min after KLS administration and, at 100 micrograms/kg i.v., lasted up to 2h, Moreover, KLS dose-dependently inhibited the increase in capillary permeability induced by BK, with a potency (ID50 23.4 micrograms/kg i.v.) slightly higher than that shown against the bronchoconstriction. KLS also prevented the bronchoconstriction and TXA2 production triggered by LTC4, but not ACH induced bronchoconstriction. In all the models studied, KLS was about 10 times more potent than NIM. These data demonstrate the capacity of KLS to counteract the bronchoconstriction induced by BK and LTC4 and to a large extent the airway inflammation induced by BK. Blockade of prostanoid production is likely to account for this protective effect, since the R-isomer of KLS was devoid of significant activity.
Animals↗
Procyanidines from Vitis vinifera seeds protect rabbit heart from ischemia/reperfusion injury: antioxidant intervention and/or iron and copper sequestering ability.
An isolated rabbit heart Langendorff preparation paced electrically was used to evaluate the effects of a highly purified, high molecular weight fraction of oligomeric procyanidines isolated from Vitis vinifera seeds on myocardial reperfusion injury after 40 minutes of low flow (1 ml/min) ischemia. Infusion of the heart with 100 or 200 micrograms/ml procyanidines dose-dependently reduced ventricular contracture during ischemia (LVEDP values decreased by 28% and 51%), decreased coronary perfusion pressure (CPP), improved cardiac mechanical performance upon reperfusion, increased the release of 6-keto-PGF1 alpha into the perfusate in both the pre-ischemic and the reperfusion periods (by 68% at 200 micrograms/ml), and suppressed rhythm irregularity. This antiarrhythmogenic action was confirmed in a more severe model of ischemia (flow rate 0.2 ml/ min). The cardioprotective agent allopurinol infused at 20 micrograms/ml had effects on the contractility and on the release of 6-keto-PGF1 alpha comparable to those of 200 micrograms/ml procyanidines. The results of the second part of this study show that procyanidines are potent scavengers of several reactive oxygen species involved in the ischemia/reperfusion damage: the superoxide anion (IC50 = 5.64 microM: rate constant K = 7.55 x 10(5) M-1 s-1, determined by the phenazine methosulfate/NADH method); the hydroxyl radical (IC50 = 28 microM; rate constant K = 1.2 x 10(12) M-1 s-1, determined by the electron spin resonance spectroscopy); peroxyl radicals (IC50 = 0.025 microM and 0.35 microM, determined using two different lipid substrates, phosphatidylcholine liposomes and methyl linoleate micelles by UV spectroscopy at 233 nm). Finally, procyanidines interact with Fe2+ and Cu2+ ions (the catalysts of HO. radicals production) giving rise to strong complexes, with stability constants (log K) ranging from 9.35 to approximately 9.
Animals↗
Vasoconstriction to polymorphonuclear leukocytes in the isolated, perfused rabbit heart: inhibition by prostacyclin mimetics.
Perfusion of the isolated rabbit heart with 5 x 10(6) human polymorphonuclear leukocytes (PMNL), under recirculating conditions (50 ml) and challenge with A-23187 (0.5 mu M) increased coronary perfusion pressure (CPP) sixfold, accompanied by increased levels of sulfidopeptide leukotrienes (CY-SLT), which had previously shown to correlate linearly with the increase in CPP. Pretreatment (20 min) of isolated rabbit hearts with the prostacyclin (PGI(2)) analogue iloprost (3 nM) resulted in significant protection against the increase in CPP and in almost complete inhibition of 5-lipoxygenase (5-LO) product synthesis. Similarly, pretreatment of isolated rabbit heart with defibrotide (200 mu g/ml), a polydeoxyribonucleotide derivative known to inhibit PMNL activation and enhance PGI(2) production by heart endothelial cells, produced significant protection against the increase in CPP and almost complete inhibition of 5-LO product synthesis. Neither iloprost nor defibrotide affected the A-23187-induced arachidonic acid (AA) metabolism in isolated PMNL alone. Inhibition of rabbit cyclooxygenase by intravenous (i.v.) administration of lysine-acetylsalicylate (60 mg/kg) 2 h before the animals were killed significantly reduced the protection provided by defibrotide, with a parallel fivefold increase in sulfidopeptide LT levels, returning to values in the range observed in control hearts. Control of endogenous modulators of leukocyte-vascular wall interactions such as PGI(2) results in significant changes in sulfidopeptide LT production in an organ model of transcellular metabolism of LT A(4), suggesting a novel mechanism of action for cardioprotective drugs in myocardial ischemia.
Animals↗
Consequences of transcellular biosynthesis of leukotriene C4 on organ function.
Formation of eicosanoids is a special mode of cell communication whereby production of eicosanoids by mixed cell populations differs from that expected from each individual cell. Transcellular biosynthesis of leukotriene C4 occurs via transfer of the reactive intermediate leukotriene A4 from neutrophils to vicinal acceptor cells devoid of 5-lipoxygenase activity such as platelets or vascular cells. Evidence for the in vivo relevance of transcellular eicosanoid metabolism results from experiments using the isolated beating rabbit heart perfused with activated neutrophils. The resultant leukotriene C4 synthesis is timely related to the pressor response of the coronary arteries and inflammatory damage of the heart by edema formation and neutrophil infiltration into the organ. Blockade of leukotriene C4 synthesis by 5-lipoxygenase inhibitors or leukotriene C4 actions by respective receptor antagonists facilitated significant protective effects. Further confirmation of the potential role of LTC4 in myocardial ischemia comes from in vivo studies in the rabbit.
Animals↗
Myocardial protection by the leukotriene synthesis inhibitor BAY X1005: importance of transcellular biosynthesis of cysteinyl-leukotrienes.
Perfusion of the isolated rabbit heart with 5 x 10(6) human polymorphonuclear leukocytes, under recirculating conditions (50 ml), and challenge with A-23187 (0.5 microM) caused an increase in coronary perfusion pressure (from a prechallenge value of 46 +/- 1.1 to 176.2 +/- 29.7 mm Hg, 30 min after challenge, n = 6-4), which was linearly correlated (P < .006) with formation of cysteinyl leukotrienes (29.7 +/- 7.3 pmol/ml, 30 min after challenge). Pretreatment with the leukotriene synthesis inhibitor BAY X1005 (1 microM) (n = 6) resulted in significant protection against the increase in coronary perfusion pressure (76.7 +/- 12.8 mm Hg, 30 min after challenge) and in almost complete inhibition of sulfidopeptide leukotriene synthesis (3.2 +/- 1.7 pmol/ml, 30 min after challenge). In in vivo experiments, ligation of the left anterior descending coronary artery in the rabbit (n = 10) resulted in acute myocardial infarction marked by a mortality rate of 60% compared with sham-operated animals (n = 10). Intravenous treatment of the rabbits with BAY X1005 (10 mg/kg/h, for 2 h) (n = 10) markedly reduced the mortality rate (20%), protected the rabbits against the marked electrocardiogram derangement and abolished the significant increase in plasma creatine phosphokinase activity and cardiac tissue myeloperoxidase activity induced by coronary artery ligation. BAY X1005 exerts a significant cardioprotection and suggests that specific leukotriene synthesis inhibitors may lead to innovative therapy in myocardial ischemia.
Animals↗
[Neutrophilic leukocytes, thrombotic risk factors in vascular diseases].
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Antihypertensive Agents↗