Tadeusz F. Krzemiński

The Time Course of Tumor Necrosis Factor-α, Inducible Nitric Oxide Synthase and Vascular Endothelial Growth Factor Expression in an Experimental Model of Chronic Myocardial Infarction in Rats

An injury to the heart due to myocardial infarction may progress to heart failure. Among the cytokines and growth factors whose interactions promote remodeling of the heart, increased expression of tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS) and vascular endothelial growth factor (VEGF) has been found. However, little is known about the sequence of gene expression during the progression of heart injury. In the present study, male Sprague-Dawley rats were used for experimental myocardial infarction performed by ligation of the left anterior descending coronary artery. TNF-α, iNOS and VEGF expression was assessed by reverse transcription polymerase chain reaction. Localization of TNF-α, VEGF and iNOS protein was assessed by immunohistochemistry. An in vitro proliferation (BrdU incorporation) and differentiation (tube formation) assay of human umbilical vein endothelial cells was performed. The expression of TNF-α, iNOS, VEGF164 and VEGF188 was observed during the whole period after myocardial infarction (on days 1, 4, 11, 28 and 40), whereas VEGF120 was found only on day 1 and 4. The most intense immunostaining for TNF-α was observed at the border zone. The iNOS immunostaining was initially located in the endothelium, whereas later it was also present in the walls of larger vessels. The VEGF protein was present in the border zone. No gene expression or immunostaining was detected in sham-operated rats. The in vitro experiments showed both proangiogenic (low TNF-α concentration, short period of incubation) and antiangiogenic (high TNF-α concentration, long period of incubation) effects of TNF-α. The expression of TNF-α and iNOS genes with the concomitant occurrence of a decrease in VEGF120, VEGF188 and VEGF164 protein could be related to insufficient angiogenesis and may suggest the possible involvement of these events in remodeling after myocardial infarction.

Comparison of Thiopental, Urethane, and Pentobarbital in the Study of Experimental Cardiology in Rats In Vivo

Background: Despite earlier research studying the influence of anesthetics in arrhythmia models, a lot of controversy remains. The aim was to compare the influence of three anesthetics (60 mg/kg thiopental, 1200 mg/kg urethane, 60 mg/kg pentobarbital intraperitoneally) on ventricular arrhythmias and to combine it with measured hemodynamic parameters to find the most suitable agent for such experiments. Method: In the model of ischemia- and reperfusion-induced arrhythmias in Sprague-Dawley rats, after left anterior descending coronary artery occlusion (7 minutes) and reperfusion (15 minutes), the following parameters have been measured or calculated: mortality index; ventricular fibrillation and tachycardia incidence and duration; systolic, diastolic, and mean arterial blood pressure; heart rate; myocardial index of oxygen consumption; and plasma creatine kinase concentration. Results: Evident depressive action of urethane on heart rate, blood pressures, and myocardial index of oxygen consumption should be reason enough to exclude it from use in such studies. Pentobarbital had no effect on arrhythmias, whereas thiopental was antiarrhythmic. Conclusions: Pentobarbital is the most suitable anesthetic offering stable hemodynamic values during arrhythmia studies. These hemodynamic values, which were similar to physiological values in awake rats, the long arrhythmia duration during reperfusion and approximately 50% mortality index are crucial parameters for evaluating antiarrhythmic drugs.

Induction of Nitric Oxide Synthase (NOS) and Vascular Endothelial Growth Factor (VEGF) in Experimental Model of Angioplasty and Heart Ischemia

Balloon angioplasty (e. g. PTCA) leads to the activation of a number of genes in injured vessels1. As a consequence of the endothelium damage several characteristic reactions, such as thrombus formation, vasoconstriction and finally - vascular smooth muscle cell (VSMC) proliferation, lead to restenosis1. Among other things, the diminished generation of nitric oxide (NO), due to the lack of constitutively expressed endothelial NO synthase (eNOS) is causatively connected with this process.

Cardioprotective effects of an active metabolite of furnidipine in 2 models of isolated heart and on in vivo ischemia–induced and reperfusion-induced arrhythmias in rats.

Dihydropyridines are known not only to have antiarrhythmic effects but also to exert a significant cardiac depressive influence. We previously showed that M-2, an active and final metabolite of furnidipine, had cardioprotective effects without the marked cardiac depression seen with this dihydropyridine. We studied the influence of M-2 infusion (10−7 M) on hemodynamics during low-flow and regional ischemia in the rat working heart. We examined the protection conferred by M-2 infusion (10−7 M) against effects of veratridine-induced intracellular calcium overload in the Langendorff heart. Additionally, we performed an in vivo study to explore the effects of oral administration of M-2 at different times and doses, in the ischemia- and reperfusion-induced arrhythmias model. M-2 improved coronary flow during low-flow and regional ischemia while favorably maintaining aortic pressure parameters. M-2 provided outstanding protection against deleterious effects of calcium overloading by significantly preventing rise in left ventricular diastolic pressure and decrease in coronary flow. M-2 reduced mortality and incidence and duration of severe arrhythmias while exhibiting differential influence on blood pressure, which depended on dose and time of administration and could suggest its clinical indication. The results of our entire study establish a beneficial cardioprotective role of M-2, which exhibited pleiotropic effects on the ischemic heart by imparting protection in various ways. This combined with good tolerance, long duration of action, low toxicity, and relatively large therapeutic window makes M-2 a promising candidate as a precursor for a new chemical class of cardioprotective drugs.

Serum omentin and vaspin levels in cirrhotic patients with and without portal vein thrombosis

AIM To investigate serum omentin and vaspin levels in cirrhotic patients; and to assess the relationship of these levels with hemostatic parameters, metabolic abnormalities, cirrhosis severity and etiology. METHODS Fifty-one cirrhotic patients (17 with portal vein thrombosis) were analyzed. Serum omentin and vaspin levels were measured with commercially available direct enzyme-linked immunosorbent assays (ELISAs). To assess platelet activity, the following tests were performed using a MULTIPLATE®PLATELET FUNCTION ANALYZER: (1) an ADP-induced platelet activation test; (2) a cyclooxygenase dependent aggregation test (ASPI test); (3) a von Willebrand factor and glycoprotein Ib-dependent aggregation (using ristocetin) test (RISTO test); and (4) a test for thrombin receptor-activating peptide-6 induced activation of the thrombin receptor, which is sensitive to IIb/IIIa receptor antagonists. RESULTS Omentin, but not vaspin, serum concentrations were significantly decreased in patients with portal vein thrombosis (PVT) (P = 0.01). Prothrombin levels were significantly increased in patients with PVT (P = 0.01). The thrombin receptor activating peptide (TRAP) test results were significantly lower in the PVT group (P = 0.03). No significant differences in adipokines serum levels were found regarding the etiology or severity of liver cirrhosis assessed according to the Child-Pugh or Model of End-Stage Liver Disease (MELD) scores. There was a significant increase in the TRAP (P = 0.03), ASPI (P = 0.001) and RISTO high-test (P = 0.02) results in patients with lower MELD scores. Serum omentin and vaspin levels were significantly down-regulated in patients without insulin resistance (P = 0.03, P = 0.02, respectively). A positive relationship between omentin and vaspin levels were found both when all of the patients were analyzed (r = 0.41, P = 0.01) and among those with PVT (r = 0.94, P < 0.001). CONCLUSION Serum omentin levels are increased in patients without PVT. Cirrhosis origin and grade do not affect omentin and vaspin levels. The analyzed adipokines do not influence platelet activity.

New approach to molsidomine active metabolites coming from the results of 2 models of experimental cardiology

Molsidomine is a well-known vasodilatating, antianginal drug. Despite earlier studies with its metabolites (3-morpholino-syndnonimine (SIN-1) and N-nitroso-N-morpholino-amino-acetonitrile (SIN-1A)), which indicated a potential favorable cardioprotective activity, a lot of controversy remains. The aim of our research was to compare molsidomine, SIN-1, SIN-1A, and lidocaine influence on arrhythmias and hemodynamic parameters in 2 experimental models in rats. In the Langendorff heart study, SIN-1A markedly elevated left ventricular systolic pressure, maximum rise and fall of the first pressure derivative, coronary flow, and myocardial oxygen consumption. In addition, SIN-1A more so than SIN-1 significantly lowered creatine kinase release. The antiarrhythmic action of SIN-1 was observed, while lidocaine significantly diminished ventricular arrhythmias duration in comparison with the control. In the ischemia-reperfusion-induced arrhythmias model, hypotensive action of molsidomine was observed as well as the reduction in pressure rate product. Molsidomine also prolonged ventricular tachycardia duration. On the other hand, no significant effects on hemodynamic parameters as well as on ventricular arrhythmias were found in any of the SIN-1 and SIN-1A groups. In conclusion, our research suggests a possible direct, cardioprotective action of SIN-1A. It seems worthwhile to further investigate molsidomine derivatives, especially SIN-1A, because of its potential use in invasive cardiology procedures such as percutaneous transluminal coronary angioplasty.