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Alpha–melanocyte-stimulating hormone (α-MSH) is a protein with known capacity for protection against cardiovascular ischemia–reperfusion (I/R) injury. This investigation evaluates the capacity of α-MSH to mitigate I/R effects in an isolated working rat heart model and determine the dependency of these alterations on the activity of heme oxygenase-1 (HO-1, hsp-32), a heat shock protein that functions as a major antioxidant defense molecule. Healthy male Sprague Dawley rats were used for all experiments. After treatment with selected doses of α-MSH, echocardiographic examinations were performed on live, anesthetized animals. Hearts were harvested from anesthetized rats pretreated with α-MSH and/or the HO-1 inhibitor SnPP, followed by cardiac function assessment on isolated working hearts, which were prepared using the Langendorff protocol. Induction of global ischemia was performed, followed by during reperfusion assessment of cardiac functions. Determination of incidence of cardiac arrhythmias was made by electrocardiogram. Major outcomes include echocardiographic data, suggesting that α-MSH has mild effects on systolic parameters, along with potent antiarrhythmic effects. Of particular significance was the specificity of dilatative effects on coronary vasculature, and similar outcomes of aortic ring experiments, which potentially allow different doses of the compound to be used to selectively target various portions of the vasculature for dilation.

Nowadays, there is a growing interest in compounds derived from plants as potential raw materials for drug development. One of the most studied compounds is beta-carotene (BC). Several clinical studies can be found investigating the cardiovascular effects of BC, however, all these results are controversial. There is an increasing body of evidence showing that besides the well-known antioxidant properties, under strong oxidative circumstances, BC could become prooxidant as well. In this study, we investigated the effects of long-term, low- and high-dose BC treatment in ischemic/reperfused (ISA/REP) hearts isolated from Zucker diabetic fatty (ZDF) rats. The animals were treated with various daily doses of BC for 4 weeks and then hearts were isolated and subjected to 30 min of global ischemia (ISA) followed by 120 min of reperfusion (REP). Blood glucose levels were measured before, after two weeks, and at the end of the treatment. In isolated hearts, the myocardial function was registered. At the end of the reperfusion period, the infarct size (IS) and heme oxygenase-1 (HO-1) expression were measured. The results showed that a low dose of BC treatment significantly improved postischemic recovery, which was reflected in a decreased IS. Interestingly, when BC was applied at high concentrations, the observed protective effects were lost. Although BC treatment increased HO-1 expression, we did not observe a better heart function and/or decreased IS in the high-dose-treated group. Glucose tolerance tests showed a concentration-independent decrease in blood glucose levels. Our results suggest that long-term, low-dose BC treatment could be effective in the treatment of type-2-diabetes and related cardiovascular diseases.

In the present study, we investigated the effects of sour cherry seed extract (SCSE) on a variety of systemic processes that contribute to general health and viability of human subjects. The experiments were conducted according to a double-blind protocol in which six healthy individuals were administered 250-mg/day SCSE for 14 days, while four were treated with placebo. Peripheral blood was collected before and after the treatment period. Samples were analyzed for levels of selected cells, enzymes, or metabolites. Subjects that received SCSE showed increases in the values of mean cell volume, serum transferrin, mean peroxidase index, and representation of peripheral blood lymphocytes. On the other hand, decreases were observed in circulating neutrophils and ferritin levels. Changes observed in the present study do not fit into a clear pattern that might yield additional in-depth understanding of SCSE-mediated alterations in physiologic responses. The most encouraging result of the present study is the absence of any indication of toxicity by subjects consuming the extract. Copyright © 2015 John Wiley & Sons, Ltd.

Objective: A rat model is here used to test a hypothesis that Momordica charantia (Bitter melon (BM)) extract favorably alters processes in cardiovascular tissue and is systemically relevant to the pathophysiology of type 2 diabetes (T2DM) and related cardiovascular disease. Methods: Male Lean and Zucker Obese (ZO) rats were gavage-treated for six weeks with 400 mg/kg body weight bitter melon (BM) extract suspended in mucin–water vehicle, or with vehicle (Control). Animals were segregated into four treatment groups, 10 animals in each group, according to strain (Lean or ZO) and treatment (Control or BM). Following six-week treatment periods, peripheral blood was collected from selected animals, followed by sacrifice, thoracotomy and mounting of isolated working heart setup. Results: Body mass of both Lean and ZO rats was unaffected by treatment, likewise, peripheral blood fasting glucose levels showed no significant treatment-related effects. However, some BM treatment-related improvement was noted in postischemic cardiac functions when Lean, BM-treated animals were compared to vehicle treated Lean control rats. Treatment of Lean, but not ZO, rats significantly reduced the magnitude of infarcted zone in isolated hearts subjected to 30 min of ischemia followed by 2 h of working mode reperfusion. Immunohistochemical demonstration of caspase-3 expression by isolated heart tissues subjected to 30 min of ischemia followed by 2 h of reperfusion, revealed significant correlation between BM treatment and reduced expression of this enzyme in hearts obtained from both Lean and ZO animals. The hierarchy and order of caspase-3 expression from highest to lowest was as follows: ZO rats receiving vehicle > ZO rats receiving BM extract > Lean rats treated receiving vehicle > Lean rats administered BM extract. Outcomes of analyses of peripheral blood content of cardiac-related analytics: with particular relevance to clinical application was a significant elevation in blood of ZO and ZO BM-treated, versus Lean rats of total cholesterol (high density lipoprotein HDL-c + low density lipoprotein LDL-c), with an inferred increase in HDL-c/LDL-c ratio—an outcome associated with decreased risk of atherosclerotic disease. Conclusions: BM extract failed to positively affect T2DM- and cardiovascular-related outcomes at a level suggesting use as a standalone treatment. Nevertheless, the encouraging effects of BM in enhancement of cardiac function, suppression of post-ischemic/reperfused infarct size extent and capacity to modulate serum cholesterol, will likely make it useful as an adjuvant therapy for the management of T2DM and related cardiovascular diseases.

Hyperthyroidism elevates cardiovascular mortality by several mechanisms, including increased risk of ischemic heart disease. Therefore, therapeutic strategies, which enhance tolerance of heart to ischemia-reperfusion injury, may be particularly useful for hyperthyroid patients. One promising cardioprotective approach is use of agents that cause (directly or indirectly) A1 adenosine receptor (A1 receptor) activation, since A1 adenosinergic pathways initiate protective mechanisms such as ischemic preconditioning. However, previously we found great A1 receptor reserve for the direct negative inotropic effect of adenosine in isolated guinea pig atria. This phenomenon suggests that weakening of atria is a possible side effect of A1 adenosinergic stimulant agents. Thus, the goal of the present investigation was to explore this receptor reserve in hyperthyroidism. Our recently developed method was used that prevents the rapid intracellular elimination of adenosine, allowing sufficient time for exogenous adenosine administered for the generation of concentration-response curves to exert its effect. Our method also allowed correction for the bias caused by the consequent endogenous adenosine accumulation. Our results demonstrate that thyroxine treatment does not substantially affect the A1 receptor reserve for the direct negative inotropic effect of adenosine. Consequently, if an agent causing A1 receptor activation is administered for any indication, the most probable adverse effect affecting the heart may be a decrease of atrial contractility in both eu- and hyperthyroid conditions.

The present study evaluates a hypothesis that sour cherry (Prunus cerasus) seed extracts (SCE) modulate CD3+ T lymphocyte activity in ways predictive of potential for uses of SCE in management of inflammatory diseases. Peripheral blood mononuclear cells (PBMC) from 12 type 2 diabetes (T2DM) patients and eight healthy control subjects were cultured 24 h with 100 ng/ml lipopolysaccharide (LPS) to increase inflammatory signaling and co-incubated with 0.5–100 µg/ml SCE. Cultures were evaluated by two-color flow cytometry for percent representation of CD3+ IL8+ and CD3 + TNF-α + cells which express interleukin-8 (IL-8), and tumor necrosis factor-α, (TNF-α+) respectively, and by enzyme-linked immunoassay for lymphocyte-associated heme oxygenase-1 (HO-1, known to be induced by SCE). SCE dosage ranges of 0.5–100 µg/ml in cell cultures significantly suppressed LPS-increased CD3 + TNF-α + and CD3 + IL8+ representation from all participants (p

Several recent studies have shown the protective effects of resveratrol in various experimental conditions and pathological animal models. Clinical studies also indicate the beneficial effects of resveratrol in different human diseases. Resveratrol produces a cascade against of events from the initial death-provoking signal, DNA fragmentation, and cell death. Researchers recognized the beneficial effect of resveratrol, as an important component, of the overall injury that occurs in various disorders such as oxidative stress, myocardial injury, anticancer activity, antidiabetic activity, and antihypercholesterolemic effects. Many mechanisms have been proposed for the initiation of protective effects of resveratrol in various pathological events, and considerable evidence exists to indicate that many mediators are involved in the resveratrol- induced protection. The present review focuses on the history, and the beneficial effects and mechanisms of resveratrol in oxidative stress, myocardial injury, anticancer-, antidiabetic- and antihypercholesterolemic activities, and discusses those therapeutic tools, which warrant becoming clinically important. s

The resveratrol-induced cardiac protection was studied in Zucker obese rats. Rats were divided into five groups: group 1, lean control; group 2, obese control (OC); group 3, obese rats treated orally with 5 mg·kg−1·day−1 of resveratrol (OR) for 2 wk; group 4, obese rats received 10% glucose solution ad libitum for 3 wk (OG); and group 5, obese rats received 10% glucose for 3 wk and resveratrol (OGR) during the 2nd and 3rd wk. Body weight, serum glucose, and insulin were measured, and then hearts were isolated and subjected to 30 min of ischemia followed by 120 min of reperfusion. Heart rate, coronary flow, aortic flow, developed pressure, the incidence of reperfusion-induced ventricular fibrillation, and infarct size were measured. Resveratrol reduced body weight and serum glucose in the OR compared with the OC values (414 ± 10 g and 7.08 ± 0.41 mmol/l, respectively, to 378 ± 12 g and 6.11 ± 0.44 mmol/l), but insulin levels were unchanged. The same results were obtained for the OG vs. OGR group. Resveratrol improved postischemic cardiac function in the presence or absence of glucose intake compared with the resveratrol-free group. The incidence of ventricular fibrillation and infarct size was reduced by 83 and 20% in the OR group, and 67 and 16% in the OGR group, compared with the OC and OG groups, respectively. Resveratrol increased GLUT-4 expression and reduced endothelin expression and cardiac apoptosis in ischemic-reperfused hearts in the presence or absence of glucose intake. Thus the protective effect of resveratrol could be related to its direct effects on the heart.

The existing literature indicates a crucial role of p38 MAP (mitogen-activated protein) kinase (p38MAPK) and its downstream target MAPKAP kinase 2 (MK2) in ischemic preconditioning (IPC). Accordingly, deletion of MK2 gene should abolish the cardioprotective ability of IPC. Interestingly, we were able to partially precondition the hearts from MK2(-/-) knockout mice suggesting the existence of an as yet unknown alternative downstream target of p38MAPK. A recent study from our laboratory also determined a crucial role of CREB (cyclic AMP response element binding protein) in IPC. Since CREB is a downstream target of MSK-1 (mitogen- and stress-activated protein kinase-1) situated at the crossroad of ERK (extracellular receptor kinase) and p38MAPK signaling pathways, we reasoned that MSK-1 could be a downstream molecular target for p38MAPK and ERK signaling in the IPC hearts. To test this hypothesis, the rat hearts were subjected to IPC by four cyclic episodes of 5 min ischemia and 10 min reperfusion. As expected, IPC induced the activation of ERK1/2, p38MAPK, MK2 and HSP (heat shock protein) 27 as evidenced by their increased phosphorylation; and the inhibition of p38MAPK with SB203580 almost completely, and the inhibition of ERK1/2 with PD098059 partially, abolished cardioprotective effects of IPC. Inhibition of MSK-1 with short hairpin RNA (shRNA) also abolished the IPC-induced cardioprotection. SB203580 partially blocked the effects of MSK-1 suggesting that MSK-1 sits downstream of p38MAPK. shRNA-MSK-1 blocked the contribution of both p38MAPK and ERK1/2 as it is uniquely situated at the downstream crossroad of both of these MAP kinases. Although MSK-1 sits downstream of both ERK1/2 and p38MAPK, ERK1/2 activation appears to play less significant role compared to p38MAPK, since its inhibition blocked MSK activation only partially. Consistent with these results, shRNA-MSK-1 blocked the partial PC in MK2(-/-) hearts, and in combination with SB203580, completely abolished the PC effects in the wild-type hearts. The IPC-induced survival signaling was almost completely inhibited with SB203580, and only partially with PD 098059 as evidenced from the inhibition patterns of IPC induced activation of CREB, Akt and Bcl-2. Again SB203580 alone or in combination with shRNA-MSK-1 inhibited IPC induced survival signal comparatively, suggesting that MSK-1 exists downstream of p38MAPK. Taken together, these results indicate for the first time MSK-1 as an alternative (other than MK2) downstream target for p38MAPK, which also transmits survival signal through the activation of CREB.

The aim of the present study was to investigate the effect of hyperthyroidism on the trans-sarcolemmal adenosine (Ado) flux via equilibrative and nitrobenzylthioinosine (NBTI)-sensitive nucleoside transporters (ENT1) in guinea pig atria, by assessing the change in the Ado concentration of the interstitial fluid ([Ado]ISF) under nucleoside transport blockade with NBTI. For the assessment, we applied our novel method, which estimates the change in [Ado]ISF utilizing the altered inotropic response to N6-cyclopentyladenosine (CPA), a relative stable selective agonist of A1 Ado receptors, by providing a relative index, the equivalent concentration of CPA. Our results show an interstitial A do accumulation upon ENT1 blockade, which was more extensive in the hyperthyroid samples (CPA concentrations equieffective with the surplus [Ado]ISF were two to three times higher in hyperthyroid atria than in euthyroid ones, with regard to the negative inotropic effect of CPA and Ado). This suggests an enhanced Ado influx via ENT1 in hyperthyroid atria. It is concluded that hyperthyroidism does not alter the prevailing direction of the Ado transport, moreover intensifies the Ado influx in the guinea pig atrium.

β-carotene (BC), a lipid-soluble tetraterpene precursor to vitamin A, widely distributed in plants, including many used in human diet, has well-known health-enhancing properties, including reducing risk of and treatment for certain diseases. Nevertheless, BC may also act to promote disease through the activity of BC derivatives that form in the presence of external toxicants such as cigarette smoke and endogenously-produced reactive oxygen species. The present investigation evaluates the dose-dependent cardioprotective and possibly harmful properties of BC in a rat model. Adult male rats were gavage-fed BC for 4 weeks, at dosages of either 0, 30 or 150mg/kg/day. Then, hearts excised from the animals were mounted in a “working heart” apparatus and subjected to 30min of global ischemia, followed by 120min of reperfusion. A panel of cardiac functional evaluations was conducted on each heart. Infarct size and total antioxidant capacity of the myocardium were assessed. Heart tissue content of heme oxygenase-1 (HO-1) by Western blot analysis; and potential direct cytotoxic effects of BC by MTT assay were evaluated. Hearts taken from rats receiving 30mg/kg/day BC exhibited significantly improved heart function at lower reperfusion times, but lost this protection at higher BC dosage and longer reperfusion times. Myocardial HO-1 content was significantly elevated dose-responsively to both BC dosage. Finally, in vitro evaluation of BC on H9c2 cells showed that the agent significantly improved vitality of these cells in a dose range of 2.5–10μM.Although data presented here do not allow for a comprehensive mechanistic explanation for reduced cardioprotection at high dose BC, it is speculated that since Fe2+ produced as a metabolite of HO-1 activity, may determine whether BC acts as an antioxidant or prooxidant agent, the strong induction of this enzyme in response to ischemia/reperfusion-induced oxidative stress may account for the high-dose BC loss of cardioprotection.

A recent study documented a role of adenosine A 3 -Akt-cAMP response element-binding protein (CREB) survival signaling in resveratrol preconditioning of the heart. In this study, we demonstrate that resveratrol-mediated CREB activation can also occur through an Akt-independent pathway. Isolated rat hearts were perfused for 15 min with Krebs-Henseleit bicarbonate (KHB) buffer containing resveratrol in the absence or presence of adenosine A 3 receptor blocker MRS-1191 [3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(±)-dihydropyridine-3,5-dicar-boxylate], phosphatidylinositol 3 (PI3)-kinase inhibitor LY294002 [2-(4-morpholinyl)-8-phenyl-1(4 H )-benzopyran-4-one hydrochloride], mitogen-activated extracellular signal-regulated protein kinase inhibitor PD098059 [2-(2-amino-3-methoxyphenyl)-4 H -1-benzopyran-4-one], or a combination of LY294002 and PD098059. All hearts were subsequently subjected to 30-min ischemia followed by 2-h reperfusion. Cardioprotection was examined by determining infarct size, cardiomyocyte apoptosis, and ventricular recovery. Resveratrol phosphorylated both Akt and CREB that was blocked by MRS-1191, which also abolished cardioprotective abilities of resveratrol. LY294002 completely inhibited Akt phosphorylation but partially blocked the phosphorylation of CREB. Inhibition of PI3-kinase also partially blocked resveratrol9s ability to precondition the heart. PD098059 partially blocked the phosphorylation of CREB and resveratrol-mediated cardioprotection. Preperfusing the hearts with LY294002 and PD098059 together completely abolished the phosphorylation of CREB, simultaneously inhibiting resveratrol-mediated cardioprotection. The results indicate that resveratrol preconditions the hearts through adenosine A 3 receptor signaling that triggers the phosphorylation of CREB through both Akt-dependent and -independent pathways, leading to cardioprotection.

The study aimed to examine whether L-carnitine and its derivatives, acetyl-L-carnitine and propionyl-L-carnitine, were equally effective and able to improve postischemic cardiac function, reduce the incidence of reperfusion-induced ventricular fibrillation, infarct size, and apoptotic cell death in ischemic/reperfused isolated rat hearts. There are several studies indicating that L-carnitine, a naturally occurring amino acid and an essential cofactor, can improve mechanical function and substrate metabolism not only in hypertrophied or failing myocardium but also in ischemic/reperfused hearts. The effects of L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine, on the recovery of heart function, incidence of reperfusion-induced ventricular fibrillation (VF), infarct size, and apoptotic cell death after 30 min ischemia followed by 120 min reperfusion were studied in isolated working rat hearts. Hearts were perfused with various concentrations of L-carnitine (0.5 and 5 mM), acetyl-L-carnitine (0.5 and 5 mM), and propionyl-L-carnitine (0.05, 0.5, and 5 mM), respectively, for 10 min before the induction of ischemia. Postischemic recovery of CF, AF, and LVDP was significantly improved in all groups perfused with 5 mM of L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine. Significant postischemic ventricular recovery was noticed in the hearts perfused with 0.5 mM of propionyl-L-carnitine, but not with the same concentration of L-carnitine or L-acetyl carnitine. The incidence of reperfusion VF was reduced from its control value of 90 to 10% (p < 0.05) in hearts perfused with 5 mM of propionyl-L-carnitine only. Other doses of various carnitines failed to reduce the incidence of VF. The protection in CF, AF, LVDP, and VF reflected in a reduction in infarct size and apoptotic cell death in hearts treated with various concentrations of carnitine derivatives. The difference between effectiveness of various carnitines on the recovery of postischemic myocardium may be explained by different membrane permeability properties of carnitine and its derivatives.

Eighteen month old spontaneously hypertensive rats (SHR-rats) showed myocardial dysfunction and autoantibodies directed against the β1-adrenoceptor similarly as known in human dilated cardiomyopathy or Chagas' disease. The agonist-like antibodies were able to activate the β1-adrenoceptor mediated signal transduction cascade in cultured rat cardiomyocytes and induced a long-lasting stimulatory effect resulting in a harmful adrenergic overdrive. The antibodies recognized an epitope of the second extracellular loop of the β1-adrenoceptor identical to that epitope identified in Chagas' disease. In conclusion, our assumption is supported that old SHR-rat are an useful animal model for investigating the role of anti-β1-adrenoceptor antibodies in the induction of human cardiomyopathy.

Modern methods of cell and molecular biology, augmented by molecular technology, have great potential for helping to unravel the complex mechanisms of various diseases. They also have the potential to help us try to dissect the events which follow the altered physiological conditions. Thus, there is every reason to believe that some of the potential mechanisms will be translated sooner or later into the clinic. Heme oxygenase (HO)-related mechanisms play an important role in several aspects of different diseases. In the past several years, significant progress has been made in our understanding of the function and regulation of HO. The objective of this article is to review current knowledge relating to the importance of HO mechanism in various diseases including myocardial ischemia/reperfusion, hypertension, cardiomyopathy, organ transplantation, endotoxemia, lung diseases, and immunosuppression. The morbidity and mortality of these diseases remain high even with optimal medical management. Furthermore, in this review, we consider various factors influencing the HO system and finally assess current pharmacological approaches to their control.

We have assessed the relationship between reperfusion-induced ventricular fibrillation (VF) and heme oxygenase (HO) mRNA expression using northern blotting, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme activity in isolated working ischemic/reperfused rat hearts. Isolated hearts were subjected to 30 min of global ischemia followed by 120 min of reperfusion. Upon reperfusion with VF, cardiac function was registered (n = 6 in each group), and HO mRNAs and enzyme activities were measured at the end of reperfusion in hearts that showed VF or did not develop VF. The expression of HO-1 mRNA (about fourfold) was observed in ischemic/reperfused nonfibrillated myocardium in comparison with the nonischemic control hearts. In those hearts when VF was developed, the expression of HO-1 mRNA was not observed in comparison with the nonischemic control myocardium. The results measured by RT-PCR and enzyme analysis support the data obtained by northern blotting. In additional studies, we decided to approach the question from a different angle. Thus, the purpose of our work was also to study the role of HO expression and enzyme activity in electrically fibrillated hearts without the ischemic/reperfused protocol. To simulate the period of 10 min of reperfusion-induced VF, hearts were electrically fibrillated, then defibrillated, and perfused for an additional 110 min, and HO-1 mRNA expression and enzyme activities were determined. Thus, electrically induced VF resulted in about 60%, 60%, and 70% reduction in HO-1 mRNA expression, RT-PCR signal intensity, and enzyme activity, respectively, compared with the nonfibrillated ischemic/reperfused group. In conclusion, our data provide evidence that the development of reperfusion-induced VF inhibits HO-1 mRNA expression and enzyme activity in both electrically fibrillated myocardium and ischemic/reperfused fibrillated hearts. The results clearly show that HO-1 mRNA expression and enzyme activity were increased in ischemic/reperfused nonfibrillated myocardium, suggesting that interventions that are able to increase HO-1 mRNA expression and enzyme activity may prevent the development of VF.

Effects of the calcineurin inhibitor FK506, the platelet-activating factor (PAF) antagonist, and free radical scavenger Ginkgo biloba extract, EGb 761, and their combination on reperfusion-induced ventricular fibrillation (VF), ventricular tachycardia (VT), and recovery of cardiac function were studied after 30 min of global ischemia followed by 2 h of reperfusion in isolated rat hearts. In the first series of studies, rats received a daily (oral) dose of 0, 1, 5, 10, 20, or 40 mg/kg/day FK506 for 10 days. FK506 dose-dependently reduced the incidence of reperfusion-induced total (irreversible plus reversible) VF from a value of 92% for untreated animals to 92% (NS), 83% (NS), 67% (NS), 33% (p

This study was conducted to evaluate the effect of Ginkgo biloba extract (EGb 761) on the nitric oxide (NO) production in relation to the recovery of postischemic cardiac function in isolated working rat hearts. Rats were orally treated with various doses (25, 50, 75, and 100 mg/kg/day) of EGb 761 for 10 days. Hearts were isolated in "working mode" and subjected to 30-min ischemia followed by 120 min of reperfusion. EGb 761 inhibited NO production measured by electron spin-resonance spectroscopy (ESR), and improved the recovery of postischemic cardiac function (coronary flow, aortic flow, left ventricular developed pressure and its first derivative) in the ischemic/reperfused myocardium. Thus in rats treated with 25, 50, 75, and 100 mg/kg/day of EGb 761 and in hearts subjected to 30-min ischemia followed by 120 min of reperfusion, aortic flow was increased from its postischemic drug-free control value of 8.0+/-0.4 to 8.6+/-0.4 ml/min (NS), 17.3+/-0.9 ml/min (p

We investigated whether the expression of heme oxygenase (HO) isozymes was related to the occurrence of ventricular fibrillation (VF) induced by ischemia/reperfusion in nondiabetic and diabetic myocardium. To study the role of HO-1 and HO-2 mRNA expression in VF, isolated hearts obtained from nondiabetic and 8-week diabetic rats were subjected to 30 min of ischemia followed by 2 h of reperfusion. Expression of HO-1 and HO-2 mRNA was studied in fibrillated and nonfibrillated myocardium using Northern blotting and reverse transcription polymerase chain reaction (RT-PCR). The effect of zinc protoporphyrin IX (Zn-PPIX), a potent inhibitor of HO activity, on HO activity was also studied in ischemic/reperfused hearts. Upon reperfusion, an expression of HO-1 was observed in nonfibrillated myocardium. HO-1 mRNA expression was significantly reduced in hearts showed VF. Zn-PPIX (5 μM) treatment reduced HO activity from its control values of 398 ± 27 (in nondiabetics) and 370 ± 20 pmol bilirubin/h (in diabetics) to 69 ± 14 (in nondiabetics, p < .05) and 60 ± 11 pmol bilirubin/h (in diabetics, p < .05), respectively, and all hearts, upon reperfusion, showed VF in both nondiabetic and diabetic subjects. HO-2 expression was unchanged in nonfibrillated and fibrillated myocardium. Postischemic function showed no correlation with the expression of these genes. Our data show that the mechanism(s) of ischemia/reperfusion-induced VF involves the downregulation of HO-1 mRNA and a reduction in HO activity. Furthermore, the mechanism(s) of VF at molecular level involving HO isozymes does not show a significant difference between nondiabetics and diabetics.

Sour cherry seed extract (SCE) was evaluated for its capacity to inhibit lipopolysaccharide-treated human peripheral blood T cells expressing tumor necrosis factor-alpha, and the chemokine interleukin-8. Both proteins are diagnostic biomarkers for inflammatory pathologies. Peripheral blood leukocytes from 11 rheumatoid arthritis (RA) patients and 8 healthy control subjects were co-cultured for 24 h in lipopolysaccharide and the extract, then evaluated by flow cytometry for T cell activation and by enzyme-linked immunoassay for lymphocyte-associated heme oxygenase-1 (HO-1) expression. There was a dose-dependent decrease in expression of the immunophenotypes: CD3+TNF-α +, and CD3+IL8 + in cultures from RA patients to a greater extent than in cells from healthy participants. These results suggest that the extract may have a modulatory roll in RA and other inflammatory disorders via the induction of HO-1, thus abating oxidative stress and strengthening regulation of pro-inflammatory signaling pathways.

Hypothesis. The present study evaluates the hypothesis that sour cherry seed extract (SCSE) protects against cardiovascular disease and inflammation in hypercholesterolemic rabbits, and that this protection correlates with SCSE-induced activity of heme oxygenase- 1 (HO-1), a cytoprotective enzyme contributing to oxidative stress responses. Methods: 18 New Zealand white rabbits were divided into three groups receiving: I. cholesterol-free rabbit chow; II. chow containing 2% cholesterol; or III. 2% cholesterol plus SCSE for 16 weeks. Heart functions were monitored by echocardiography 0, 4, and 16 weeks after the initiation of cholesterol-supplemented feeding. At the 16-week time-point, isolated hearts were subjected to ischemia-reperfusion (I/R), followed by measurement of heart rate (HR), aortic flow (AF), coronary flow (CF), aortic pressure (AoP), and left ventricular developed pressure (LVDP). Myocardial infarct size was determined using triphenyl tetrazolium chloride (TTC). Quantification of fatty streaks was assessed using Sudan-III staining. Western blot analysis was used to determine the content of cytochrome c oxidase III (COX III), vascular endothelial growth factor (VEGF), and HO-1 in the myocardium. Results: Relative to cholesterol-treated animals not receiving SCSE, SCSE-treated animals exhibited significantly improved cardiac function and improved peak early diastolic velocity to peak atrial velocity ratio (E'/A'), along with decreased atherosclerotic plaque formation and infarct size. Increased HO-1 and COX III protein expression and COX activity were also noted in hearts from SCSE-treated rabbits. Conclusions: This study demonstrates SCSE cardioprotective effects on hypercholesterolemic hearts. Correlation of these outcomes with HO-1 expression suggests that the effect may be mediated by activity of this enzyme. However, definitive proof of HO-1 dependence requires further investigation.

Effects of preconditioning and Ginkgo biloba extract (EGb 761) were studied in isolated nondiabetic and diabetic ischaemic and re-perfused rat hearts. Hearts were randomly divided into five groups in both the age-matched non-diabetic and the 8-week streptozotocin-induced diabetic groups: Group I, hearts were subjected to 30 min of global ischaemia followed by 30 min of re-perfusion; Group II, one cycle of preconditioning consisting of 5 min ischaemia and 10 min re-perfusion before the induction of 30 min of ischaemia and 30 min of re-perfusion; Group III, two cycles of preconditioning; Group IV, three cycles; and Group V, four cycles before the onset of 30 min ischaemia followed by 30 min of re-perfusion. Four cycles of ischaemic preconditioning resulted in a reduction of arrhythmias in non-diabetic rats. Thus, in non-diabetics, the incidence of ventricular fibrillation and tachycardia fell from 92% and 100% (no preconditioning) to 33% (p < 0.05) and 42% (p < 0.05), respectively. Four cycles of preconditioning failed to reduce the incidence of re-perfusion arrhythmias in diabetic subjects. Preconditioning reduced the formation of oxygen free radicals measured by electron spin resonance spectroscopy, but the recovery of cardiac function was low in all non-diabetic and diabetic preconditioned groups. EGb 761 at 25 and 50 mg/kg improved cardiac function in non-preconditioned and preconditioned non-diabetic and diabetic hearts. During re-perfusion in the four-cycle preconditioned non-diabetic and diabetic groups, the amount of free radicals was reduced approximately by 50 and 70% using 25 and 50 mg/kg of EGb 761, respectively. EGb 761 improved cardiac function after ischaemia in both non-preconditioned and preconditioned non-diabetic and diabetic rats. Our data suggest that diabetes could abolish the precondition-induced protection.

Objective: Studies have shown that the diabetic heart exhibits abnormalities in cellular ion transport, which can affect susceptibility to reperfusion-induced ventricular fibrillation (VF), tachycardia (VT) and functional derangements. It has been shown that “preconditioning” renders the heart very resistant to a subsequent prolonged ischemic episode. This phenomenon has been extensively studied in healthy myocardium, but such a study has not been previously done in diseased (hypertrophic or myopathic) hearts. Methods: We studied the incidence of reperfusion-induced VF, VT, cardiac function, and ion shifts (Na+, K+, Ca2+, and Mg2+) induced by ischemia/reperfusion in isolated hearts from rats with streptozotocin-induced diabetes. Following 2, 4, 6, and 8 weeks of diabetes, hearts were isolated and subjected to 30 min global ischemia followed by reperfusion. Results: In the 2-week diabetic group the total incidence of VF and VT was reduced from their non-diabetic age-matched control value of 100 and 100% to 42 ( P < 0.05) and 42% ( P < 0.05), respectively. Such a reduction in the incidence of VF and VT was not observed with progressive diabetes (4, 6, and 8 weeks). In the 2-week diabetics, the reduction in the VF and VT was reflected in the improvement of postischemic function, the reduction of ischemia and reperfusion-induced Na+ and Ca2+ gains, and the prevention in K+ and Mg2+ loss. This diabetes-induced initial protection was not seen in the 4- and 6-week diabetics, and a deterioration of postischemic function was observed in the 8-week diabetics. Four cycles of preconditioning, each consisting of 5 min ischemia followed by 10 min reperfusion, failed to reduce the incidence of VF and VT, improve cardiac function, and prevent ion shifts induced by 30 min ischemia followed by 30 min reperfusion in 4- and 8-week diabetics. Conclusions: In the early phase of diabetes the heart is more resistant to ischemia/reperfusion than the non-diabetic heart. Preconditioning does not afford protection against a prolonged period of ischemia in diabetics, indicating that preconditioning may be a “healthy heart phenomenon”.

Novel strategies are evaluated for management of allergic rhinitis and asthma in patients co-afflicted with both disorders. It is hypothesized that the platelet activating factor receptor antagonist ginkgolide B (GB) and the carotenoid antioxidant astaxanthin (ASX) interact with antihistamines cetirizine dihydrochloride (CTZ) and azelastine (AZE) to potentiate their ability to downregulate potentially pathological immune activation. Peripheral blood mononuclear cells from asthmatics and healthy subjects, cultured 24 hours with 50 μg/ml phytohemaglutinin (PHA) or PHA plus each drug are analyzed by flow cytometry for expression of CD25+ or HLA-DR+ by CD3+ (T cells). Results are reported as stimulation indices for CD3+CD25+ (SICD3+CD25+) and CD3+HLA-DR+ (SICD3+HLADR+) cells in cultures treated with PHA alone, versus cultures treated with both PHA and drugs. Optimal suppression of activated cells was observed in cultures stimulated with ASX 10-6 M + CTZ 10-6 M (SICD3+CD25+, p = 0.016; SICD3+HLADR, p = 0.012); ASX 10-6 M + AZE 10-6 M (SICD3+CD25+, p = 0.012; SICD3+HLADR, p = 0.015); GB 10-6 M + CTZ 10-6 M (SICD3+CD25+, p = 0.024, SICD3+HLADR+, p = 0.019). Results demonstrate improved activity of antihistamines by 2 phytochemicals, suggesting dosing strategies for animal trials of ASX- or GB-augmented formulations for seasonal allergic rhinitis and asthma.

A recent study demonstrated biochemical and structural alterations of peroxisomes in rat kidney after ischemia/reperfusion. We examined whether peroxisomes play any role in the pathophysiology of myocardial ischemia/reperfusion injury. Isolated perfused rat heart was made ischemic for 30 min by terminating coronary flow (CF), followed by 30-min reperfusion. Experiments were divided into two groups; the experimental group received 1-O-hexadecyl-Sn-glycerol (chimyl alcohol) (25, 50, and 100 microM) before ischemia, and the control group received an equivalent amount of saline. Two of the experimental groups (50 and 100 microM) demonstrated improved postischemic myocardial performance, as demonstrated by accelerated recovery in left ventricular developed pressure (LVDP) and CF, as well as reduction in the incidence of ventricular fibrillation (VF). However, because the heart rate (HR) was significantly reduced in the 100-microM chimyl alcohol group, subsequent studies were performed with 50 microM chimyl alcohol as the optimal dose. Chimyl alcohol (50 microM) also reduced cellular injury, as evidenced by reduced creatine kinase (CK) release, and decreased development of oxidative stress, as evidenced by reduced formation of malonaldehyde (MDA). Peroxisomal catalase activity was decreased in the control group after ischemia/reperfusion, and chimyl alcohol treatment restored the activity of the enzyme. Our results indicate that chimyl alcohol, a precursor of ether-linked phosphoglyceride biosynthesis, can reduce myocardial ischemia/reperfusion injury, possibly by restoring catalase activity and reducing oxidative stress through synthesis of ether lipids, suggesting a possible role of peroxisomal disorder in ischemia/reperfusion injury.

Objectives. This study was conducted to elucidate the role of the adenosine triphosphate (ATP)-sensitive potassium channel blocking agent glibenclamide and the opener cromakalim in the mechanism of reperfusion-induced injury. Background. Recently, ATP-sensitive potassium channel openers have been proposed to reduce ischemia/reperfusion-induced injury, including arrhythmias and heart function. Thus, one night hypothesize that pharmacologic agents that enhance the loss of potassium ions in the myocardium through ATP-sensitive potassium channels would be arrhythmogenic, and agents that interfere with tissue potassium ion loss would be antiarrhythmic. Methods. Isolated “working” guinea pig hearts and phosphorus-31 nuclear magnetic resonance spectroscopy were used to study the recovery of myocardial function and phosphorus compounds after 30, 40 and 50 min of normothermic global ischemia followed by reperfusion in untreated control and glibenclamide-and cromakalim-treated groups. Results. After 30 min of ischemia, 1, 3, 10 and 30 μmol/liter of glibenclamide dose-dependently reduced the incidence of reperfusion-induced ventricular fibrillation (total) from its control value of 92% to 75%, 33% (p Conclusions. The preservation of myocardial potassium ions and phosphorus compounds by glibenclamide can improve the recovery of postischemic function, but the use of ATP-sensitive potassium channel openers as antihypertensive or antiarrhythmic agents may be of particular concern in those postinfarction patients who are known to be at high risk for sudden cardiac death.

International audience; Leptin is known to exert cardiodepressive effects and to induce left ventricular (LV) remodelling. Nevertheless, the autocrine and/or paracrine activities of this adipokine in the context of post-infarct dysfunction and remodelling have not yet been elucidated. Therefore, we have investigated the evolution of myocardial leptin expression following myocardial infarction (MI) and evaluated the consequences of specific cardiac leptin inhibition on subsequent LV dysfunction. Anaesthetized rats were subjected to temporary coronary occlusion. An antisense oligodesoxynucleotide (AS ODN) directed against leptin mRNA was injected intramyocardially along the border of the infarct 5 days after surgery. Cardiac morphometry and function were monitored by echocardiography over 11 weeks following MI. Production of myocardial leptin and pro-inflammatory cytokines interleukin (IL)-1β and IL-6 were assessed by ELISA. Our results show that (1) cardiac leptin level peaks 7 days after reperfused MI; (2) intramyocardial injection of leptin-AS ODN reduces early IL-1β and IL-6 overexpression and markedly protects contractile function. In conclusion, our findings demonstrate that cardiac leptin expression after MI could contribute to the evolution towards heart failure through autocrine and/or paracrine actions. The detrimental effect of leptin could be mediated by pro-inflammatory cytokines such as IL-1β and IL-6. Our data could constitute the basis of new therapeutic approaches aimed to improve post-MI outcome.

This study tested the hypothesis that the induction of autophagy by producing therapeutic amounts of endoplasmic reticulum (ER) stress in the heart before an ischemic insult would ameliorate/reduce subsequent lethal myocardial ischemic/reperfusion (I/R) injury (similar to ischemic preconditioning). A dose-response study with both tunicamycin and thapsigargin was performed to determine the optimal dose (0.3 mg/kg) for inducing autophagy for cardioprotection. The Sprague-Dawley rats weighing between 250 and 300 g were randomly assigned into five groups: normal control (injected with saline only), high (3 mg/kg), and low (0.3 mg/kg) doses of tunicamycin or thapsigargin, respectively. After 48 h, the rats were subjected to an isolated working heart preparation: 30 min ischemia followed by 2 h of reperfusion with continuous left ventricular function monitoring. At the end, the hearts were subjected to either measurement of infarct size or cardiomyocyte apoptosis. Some hearts (from different sets of experiments) were used for transmission electron microscopy (TEM), confocal microscopy, or Western blot analysis. Tunicamycin and thapsigargin, irrespective of the dose, induced sufficient ER stress, as evidenced by the increased phosphorylation or activation of eIF2α and PERK. Such ER stress potentiated autophagy in the heart, as evidenced by an increase in LC3-II, beclin-1, and Atg5. This was also supported by TEM, clearly showing the production of autophagosomes, and by confocal microscopy, showing upregulation of eIF2α and beclin-1. The autophagy produced with lower doses of tunicamycin and thapsigargin in the face of myocardial I/R resulted in reduction of the I/R injury, as evidenced by improved left ventricular function and reduced myocardial infarct size and cardiomyocyte apoptosis. In concert, an induction of GRP78 and activation of Akt and Bcl-2 occurred. The higher doses conversely were detrimental for the heart and were associated with induction of CHOP and downregulation of Akt. The results thus display the proof of concept that induction of autophagy by ER stress (therapeutic amount) before ischemia (similar to ischemic preconditioning) could reduce subsequent lethal ischemic reperfusion injury.

The study has analysed the action of histamine in the rabbit venous system and evaluated its potential role in contraction during increased venous pressure. We have found that a great variety exists in histamine sensitivity and H(1) -histamine receptor expression in various types of rabbit veins. Veins of the extremities (saphenous vein, femoral vein, axillary vein) and abdomen (common iliac vein, inferior vena cava) responded to histamine by a prominent, concentration-dependent force generation, whereas great thoracic veins (subclavian vein, superior vena cavas, intrathoracic part of inferior vena cava) and a pelvic vein (external iliac vein) exhibited slight sensitivity to exogenous histamine. The lack of reactivity to histamine was not due to increased activity of nitric oxide synthase (NOS) or heme oxygenase-1. H(1) -histamine receptor expression of veins correlated well with the histamine-induced contractions. Voltage-dependent calcium channels mediated mainly the histamine-induced force generation of saphenous vein, whereas it did not act in the inferior vena cava. In contrast, the receptor-operated channels were not involved in this response in either vein. Tyrosine phosphorylation occurred markedly in response to histamine in the saphenous vein, but not in the inferior vena cava. Histamine induced a prominent ρ kinase activation in both vessels. Protein kinase C and mitogen-activated protein kinase (MAPK) were not implicated in the histamine-induced intracellular calcium sensitization. Importantly, transient clamping of the femoral vein in animals caused a short-term constriction, which was inhibited by H(1) -histamine receptor antagonist in vivo. Furthermore, a significantly greater histamine immunopositivity was detected in veins after stretching compared to the resting state. We conclude that histamine receptor density adapts to the actual requirements of the circulation, and histamine liberated by the venous wall during increased venous pressure contributes to the contraction of vessels, providing a force for the venous return.

We have shown earlier that prostacyclin (PGI2) and its stable analogue: 7-oxo-prostacyclin(7-OXO) may induce a prolonged, late appearing (24-48 h after drug administration), dose dependent protection of the heart from harmful consequences of a subsequent severe ischaemic stress, such as myocardial ischaemia, life-threatening ventricular arrhythmias and early ischaemic morphological changes. In an other study we observed that a similar but shortlived (less than 1 h) cardioprotection, induced by 'preconditioning' brief coronary artery occlusions, is greatly reduced by blockade of the cyclooxygenase pathway, suggesting that prostanoids might play a role in this shortlasting protection. Objective of our present study was to elucidate the importance of some arachidonic acid (AA) metabolites, such as PGI2 and thromboxane A2 (TXA2) in the mechanism of the late appearing, prolonged cardioprotection. Estimation of the metabolites: 6-keto-PGF1 alpha (6-KETO) and thromboxane B2 (TXB2) was made from the perfusate of isolated Langendorff hearts of guinea-pigs pretreated with 50 micrograms/kg 7-OXO, 24 and 48 h before preparation. Pretreatment alone produced a slight, but significant elevation of 6-KETO (from 206 +/- 11 to 284 +/- 19 pg/ml/min after 24 h, and to 261 +/- 18 pg/ml/min after 48 h). No change was seen in TXB2 production. Global ischaemia for 25 min (followed by 25 min reperfusion) markedly increased the release of both AA metabolites; maximal values were observed in the third min of reperfusion (6-KETO from 206 +/- 11 to 1275 +/- 55 pg/ml/min and TXB2 from 29 +/- 4 to 172 +/- 12 pg/ml/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Recent studies suggest that glutaredoxin-1 (Glrx-1) may serve as therapeutic target for diabetic hearts. As the level of reactive oxygen species (ROS) is increased in the pathologic hearts including ischemia/reperfusion (I/R) and diabetes, we assumed that upregulation of Glrx-1 could reduce the cardiac risk factors associated with I/R and/or diabetes. Diabetes was induced in mice by i.p. injection of streptozotocin (150 mg kg(-1)). Eight days after when the blood glucose was elevated to 400 mg per 100 ml, the animals were randomly assigned to one of the following three groups, which received either empty vector, or LacZ or Glrx-1 adenoviral construct. Four days later, isolated working hearts were subjected to 30 min ischemia followed by 2 h reperfusion. Glrx-1 gene therapy significantly enhanced the Glrx-1 level, which prevented I/R-mediated reduction of ventricular recovery, increased myocardial infarct size and cardiomyocyte apoptosis in diabetic myocardium. In concert, Glrx-1 prevented diabetes and ischemia-reperfusion induced reduction of cardioprotective proteins including Akt, FoxO-1, and hemeoxygenase-1, and abolished the death signal triggered by Jnk, p38 mitogen-activated protein kinase, and c-Src. Glrx-1 gene therapy seems to prevent cardiac complications in diabetic heart due to the I/R by switching the death signal into survival signal by activating Akt-FoxO-signaling network.

We studied the effects of cicletanine, a furopyridine antihypertensive drug, and furosemide, a loop diuretic, on ventricular arrhythmias, such as sustained ventricular fibrillation (VF) and ventricular tachycardia (VT), and myocardial ion content in Langendorff rat hearts subjected to 30min global ischaemia then 10 min reperfusion. Myocardial Na+ K+ Ca2+ and Mg2+ concentrations were measured by washout technique and atomic absorption spectrophotometry before and after ischaemia and reperfusion. Drugs were either perfused (acute treatment) or orally gavaged daily to the rats for 14 days before isolation of their hearts (chronic treatment). Under in vitro conditions 10−5, 3 × 10−5, 10−4 or 3 × 10−4 M of cicletanine reduced the incidence of sustained VF and VT from the control values of 91% and 100% to 83% and 100%, 50% (P

Although excessive consumption of ethanol in alcoholic beverages causes multi-organ damage, moderate consumption, particularly of red wine, is protective against all-cause mortality. These protective effects could be due to one or many components of the complex mixture of bioactive compounds present in red wine including flavonols, monomeric and polymeric flavan-3-ols, highly coloured anthocyanins as well as phenolic acids and the stilbene polyphenol, resveratrol. The therapeutic potential of resveratrol, firstly in cancer chemoprevention and then later for cardioprotection, has stimulated many studies on the possible mechanisms of action. Further indications for resveratrol have been developed, including the prevention of age-related disorders such as neurodegenerative diseases, inflammation, diabetes and cardiovascular disease. These improvements are remarkably similar yet there is an important dichotomy: low doses improve cell survival as in cardio- and neuro-protection yet high doses increase cell death as in cancer treatment. Fewer studies have examined the responses to other components of red wine, but the results have, in general, been similar to resveratrol. If the non-alcoholic constitutents of red wine are to become therapeutic agents, their ability to get to the sites of action needs to be understood. This mini-review summarizes recent studies on the possible mechanisms of action, potential therapeutic uses and bioavailability of the non-alcoholic constitutents of alcoholic beverages, in particular resveratrol and other polyphenols.

We studied the effects of cicletanine, an anti-hypertensive drug, on reperfusion arrhythmias in relation to 6-keto-PGF1 alpha, thromboxane B2 (TXB2), and ion shifts (Na+, K+, Ca2+, and Mg2+) induced by ischemia and reperfusion in hearts isolated from spontaneously hypertensive rats. Hearts were subjected to 30-min global ischemia followed by 10-min reperfusion. 6-keto-PGF1 alpha and TXB2 concentrations were determined by radioimmunoassay (RIA) from coronary effluents, and myocardial Na+, K+, Ca2+, and Mg2+ contents were measured by atomic absorption spectrophotometry from myocardial tissue. Two basic protocols were used: (a) acute administration when 3, 10, 30, or 100 mg/L cicletanine was included in the perfusion buffer; and (b) chronic application, in which rats received cicletanine 3, 10, 30, or 100 mg/kg/day orally for 14 days. Acute administration of the drug in low concentrations (3 or 10 mg/L), significantly increased endogenous 6-keto-PGF1 alpha production before ischemia and during reperfusion, whereas higher doses of cicletanine (30 or 100 mg/L) as well as chronic application of the drug failed to increase production of 6-keto-PGF1 alpha in the myocardium. TXB2 production was not influenced by either acute or chronic treatment with the drug. Neither treatment changed myocardial ion contents in comparison with control values (Na+ = 45 +/- 4, K+ = 252 +/- 7, Ca2+ = 1.4 +/- 0.1, and Mg2+ = 12.5 +/- 0.3 mmol/kg dry weight) in nonischemic hearts. Thirty-minute ischemia resulted in a two- and fourfold accumulation of myocardial Na+ and Ca2+ and a 50% decrease in both K+ and Mg2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Coenzyme Q10 (CoQ10) has been extensively studied as adjunctive therapy for ischemic heart disease, and its cardioprotective ability is well-established. The mitochondrial respiratory chain contains several coenzymes, including CoQ1, CoQ2, CoQ4, CoQ6, CoQ7, CoQ8, CoQ9, and CoQ10. It is not known whether other CoQs, especially CoQ9, is equally cardioprotective as CoQ10. The present study was designed to determine if CoQ 9 could protect guinea pig hearts from ischemia reperfusion injury. Guinea pigs were randomly divided into three groups: groups I and II were fed CoQ 9 and CoQ10, respectively, for 30 days while group III served as control. After 30 days, the guinea pigs were sacrificed and isolated hearts were perfused via working mode were subjected to 30 min ischemia followed by 2 h of reperfusion. Cardioprotection was assessed by evaluating left ventricular function, ventricular arrhythmias, myocardial infarct size, and cardiomyocyte apoptosis. Samples of hearts were examined for the presence of CoQ9 and CoQ10. The results demonstrated that both CoQ9 and CoQ10 were equally cardioprotective, as evidenced by their abilities to improve left ventricular performance and to reduce myocardial infarct size and cardiomyocyte apoptosis. High performance liquid chromatographic (HPLC) analysis revealed that a substantial portion of CoQ9 had been converted into CoQ10. The results indicate that CoQ9 by itself, or after being converted into CoQ10, reduced myocardial ischemia/reperfusion-induced injury.

The aim of our study was to investigate the contribution of the adrenocorticotropic hormone fragment, ACTH (4-10), on the recovery of postischemic cardiac function. Effects of ACTH (4-10) on caspase-3 activity, cardiomyocyte and endothelial apoptosis, and HO-1 protein expression were studied. Rats were treated with various doses of ACTH (4-10), and then 12 h later, anesthetized, hearts were isolated, perfused, and subjected to 30-min ischemia followed by 120-min reperfusion. Cardiac function including heart rate, coronary flow, aortic flow, and left ventricular developed pressure were recorded. After 120-min reperfusion, 200 mug/kg of ACTH (4-10) significantly improved the recovery of aortic flow, coronary flow, and left ventricular developed pressure from their untreated control values of 15.3 +/- 0.9 ml/min, 6.5 +/- 0.9 ml/min, and 10 +/- 0.6 kPa to 20.7 +/- 1.3 ml/min, 24.8 +/- 1.8 ml/min and 13.7 +/- 0.7 kPa, respectively. Heart rate did not show significant changes during reperfusion. ACTH (4-10) treatment resulted in a reduction in infarct size, caspase 3 activity, apoptosis, and an increase in HO-1 expression. When ACTH (4-10) was given at the moment of reperfusion, the drug failed to improve the postischemic recovery of the myocardium. Thus, ACTH (4-10) can be a useful tool for the prevention of the development of ischemia/reperfusion-induced injury.

The effects of kernel extract obtained from sour cherry ( Prunus cerasus) seed on the postischemic cardiac recovery were studied in isolated working rat hearts. Rats were treated with various daily doses of the extract for 14 days, and hearts were then isolated and subjected to 30 min of global ischemia followed by 120 min of reperfusion. The incidence of ventricular fibrillation (VF) and tachycardia (VT) fell from their control values of 92% and 100% to 50% (not significant) and 58% (not significant), 17% ( P < 0.05), and 25% ( P < 0.05) with the doses of 10 mg/kg and 30 mg/kg of the extract, respectively. Lower concentrations of the extract (1 and 5 mg/kg) failed to significantly reduce the incidence of VF and VT during reperfusion. Sour cherry seed kernel extract (10 and 30 mg/kg) significantly improved the postischemic recovery of cardiac function (coronary flow, aortic flow, and left ventricular developed pressure) during reperfusion. We have also demonstrated that the extract-induced protection in cardiac function significantly reflected in a reduction of infarct size. Immunohistochemistry indicates that a reduction in caspase-3 activity and apoptotic cells by the extract, beside other potential action mechanisms of proanthocyanidin, trans-resveratrol, and flavonoid components of the extract, could be responsible for the cardioprotection in ischemic-reperfused myocardium.

Several accepted methods are available to estimate the adenosine (Ado) concentration of interstitial fluid ([Ado]ISF) in functioning heart, providing results spanning over nano- to micromolar concentrations. This extremely large range points to the necessity of novel approaches for estimating [Ado]ISF or at least the alteration from basal [Ado]ISF. In the present study, the change in [Ado]ISF was characterized following nucleoside transport (NT) blockade elicited by 10 micromol/L dipyridamole or 10 micromol/L nitrobenzylthioinosine in isolated guinea pig atria, by means of our novel procedure referred to as receptorial responsiveness method (RRM). The RRM provided an index of the change in [Ado]ISF under NT blockade, namely the concentration of N-cyclopentyladenosine (CPA; a relatively stable A1 Ado receptor agonist), which is equieffective with the change in [Ado]ISF regarding the contractility. Our results show that dipyridamole or nitrobenzylthioinosine produced an elevation in [Ado]ISF at the cardiomyocyte A1 Ado receptors equivalent to about 16 or 20 nmol/l CPA, respectively. In addition, nitrobenzylthioinosine was found more appropriate for selective NT blockade than dipyridamole.

International audience; Recent studies have demonstrated that electrical uncoupling at gap junctions during ischemia is associated with cardiac Connexin-43 (Cx43) dephosphorylation. Whether oxidative stress is involved in this phenomenon still remains unclear. In the present study, we examined the influence of selenium intake on reperfusion-induced Cx43 dephosphorylation. Male Wistar rats were fed a diet containing either 0.05 mg/kg (Low-Se, n = 13) or 1.5 mg/kg (High-Se, n = 11) selenium for 8 weeks. At the end of this diet, hearts were isolated and subjected to 10 min regional ischemia followed by 10 min reperfusion. The level of dephosphorylated Cx43 was determined in tissue samples from ischemic/reperfused and non-ischemic regions of the hearts. At the end of the experiemental diet, the activity of the antioxidant enzyme glutathione peroxidase (GSH-Px) was increased in high-Se hearts compared with low-Se hearts (+ 13%; p < 0.05). After ischemia/reperfusion, in low-Se hearts, Cx43 dephosphorylation appeared significantly increased in the left ventricle compared to the non-ischemic right ventricle (+ 149%; p < 0.05). The high-Se diet significantly reduced Cx43 dephosphorylation in the left ventricle (p < 0.05 vs. low-Se diet). In conclusion, our results suggest that oxidative stress may be involved in Cx43 dephosphorylation during myocardial ischemia/reperfusion, thereby contributing to arrhythmogenesis.

International audience; Prospective epidemiological studies have shown that the incidence of numerous cardiovascular pathologies is correlated with body selenium status. However, it remains unclear whether selenium status also influences the outcome of myocardial infarction. The aim of the present study was to test whether dietary selenium intake affects myocardial necrosis induced by transient regional ischemia in vivo in rats. For this purpose, male Wistar rats received either a high-selenium (High-Se: 1.5 mg of Se/kg) or a low-selenium (Low-Se: 0.05 mg of Se/kg) diet for 10 weeks. Animals were subjected to 30 min of myocardial ischemia induced by coronary artery ligation followed by 60 min of reperfusion. Pre- and postischemic blood samples were collected for glutathione (GSH and GSSG) determination and for glutathione peroxidase (GSH-Px) assessment. Our results show that high-selenium intake reduces myocardial infarct size (High-Se: 25.16 +/- 1.19% versus Low-Se: 36.51 +/- 4.14%, p < 0.05), preserves postischemic GSH/GSSG ratio (High-Se: 1.37 +/- 0.37 versus Low-Se: 0.47 +/- 0.10, p < 0.05), increases plasma GSH-Px activity, and improves postischemic mean arterial pressure. In conclusion, preischemic body selenium status is a major determinant of the outcome of myocardial ischemia in vivo in rats probably because it influences the cellular redox status.

We studied the effects of various cycles of preconditioning (PC) (one cycle, 1 x PC; two cycles, 2 x PC; three cycles, 3 x PC; and four cycles, 4 x PC) on cardiac function, infarct size, and the incidence of reperfusion-induced arrhythmias in isolated hearts obtained from rabbits with hypercholesterolemia. After 8 weeks of hypercholesterolemia, hearts were subjected to 30 min of ischemia followed by 120 min of reperfusion. Various cycles of PC resulted in a "cycle-dependent" reduction in infarct size in the age-matched nonhypercholesterolemic group. In the 8-week hypercholesterolemic group, increasing cycles of PC resulted in a significant increase in infarct size from their nonpreconditioned ischemic/reperfused control value of 44 +/- 5% to 45 +/- 6%, 49 +/- 5%, 59 +/- 6% (p < 0.05), and 58 +/- 5% (p < 0.05), respectively. PC increased the vulnerability of the myocardium to reperfusion-induced arrhythmias in hypercholesterolemics indicating that PC may be an "intact heart" phenomenon. The effects of PC appear currently to be a dilemma in laboratories and clinics. The solution to the problem of PC in intact and diseased myocardium requires further data from two different sources: (a) previously "diseased" animals, and (b) diseased human myocardium from clinics. Once these data are available, then the effects under which PC will be beneficial rather than harmful could be established and the dilemma solved.

We investigated the contribution of dexamethasone treatment on the recovery of postischemic cardiac function and the development of reperfusion-induced arrhythmias in ischemic/reperfused isolated rat hearts. Rats were treated with 2 mg/kg of intraperitoneal injection of dexamethasone, and 24 hours later, hearts were isolated according to the 'working' mode, perfused, and subjected to 30 min global ischemia followed by 120 min reperfusion. Cardiac function including heart rate, coronary flow, aortic flow, and left ventricular developed pressure were recorded. After 60 min and 120 min reperfusion, 2 mg/kg of dexamethasone significantly improved the postischemic recovery of aortic flow and left ventricular developed pressure from their control values of 10.7 +/- 0.3 ml/min and 10.5 +/- 0.3 kPa to 22.2 +/- 0.3 ml/min (p0.05) and 14.3 +/- 0.5 kPa (p0.05), 19.3 +/- 0.3 ml/min (p0.05) and 12.3 +/- 0.5 kPa (p0.05), respectively. Heart rate and coronary flow did not show a significant change in postischemic recovery after 60 or 120 min reperfusion. In rats treated with 0.5 mg/kg of actinomycin D injected i.v., one hour before the dexamethasone injection, suppressed the dexamethasone-induced cardiac protection. Electrocardiograms were monitored to determine the incidence of reperfusion-induced ventricular fibrillation. Dexamethasone pretreatment significantly reduces the occurrence of ventricular fibrillation. Cytochrome c release was also observed in the cytoplasm. The results suggest that the inhibition of cytochrome c release is involved in the dexamethasone-induced cardiac protection.

In less than 40 years of the first human gene being isolated, which involves putting isolated and manipulated DNA (genes) back into individuals for treatments of genetic diseases. Gene therapy is now more widely accepted to encompass all forms of therapeutic intervention in which DNA is used to alter the overall pattern of gene expression within an organ. Potential applications of gene therapy are widespread and implications for the management of various human diseases are becoming available. Approaches are being developed to overcome difficulties and identify a number of potential applications (1). The management of cardiovascular diseases includes the treatment of genetic diseases related to disorders of lipid metabolism and of acquired disease focusing on atherosclerosis and restenosis following angioplasty, thus, the introduction of DNA into the arterial wall. It is now relatively well accepted that much of human disease can and should be treated at the level of underlying genetic manipulation. Much of the theoretical basis of gene therapy are going to be worked out step by step (2). What we face now is the difficult task of developing the technology required to put these ideas into an actual clinical situation. Although it is relatively easy to get DNA into cells under experimental conditions, it remains much more difficult to do so with the efficiency required for therapy in clinics. What then are the implications for cardiovascular disease? Several approaches have also been made to modify cell phenotype including inhibition of gene function associated with cell proliferation and to arrest the progress of atherosclerosis and restenosis, and the local production of growth factors to promote angiogenesis (e.g., VEGF. These procedures are of potential use in the treatment of peripheral vascular diseases and myocardial ischemia. Although DNA is taken up by cardiac myocytes relatively efficiently, it is currently difficult to envisage global treatment of different parts of a diseased myocardium. For instance, the direct injection of genes leads to highly localized DNA uptake; adenovirus provides potential for more global DNA transfer but elicits a strong immune response in the body. There is an increasing interest in the molecular regulation of introduced gene(s) to elicit regionally specific effects i.e., directed for to regions of hypoxia or other stress. Approaches most likely to succeed in gene therapy remain a subject for speculation and based on experimental findings. We should also take caution and not only overestimate the importance of gene therapy at this early, but promising stage. These are exciting times but it takes additional and substantial effort before gene therapy makes real impact in humans. What appears certain is that cardiovascular diseases will be a major of therapeutic applications.

The contribution of alpha-melanocyte-stimulating hormone (alpha-MSH) treatment, an active fragment of adrenocorticotropic hormone (ACTH), to the recovery of postischemic cardiac function, infarct size, the incidence of reperfusion-induced ventricular fibrillation and apoptotic cell death was studied in ischemic/reperfused isolated rat hearts. Rats were subcutaneously injected with 40, 200 and 400 microg/kg of alpha-MSH, and 12 h later, hearts were isolated, perfused and subjected to 30 min of ischemia followed by 120 min of reperfusion. Thus, after 120 min of reperfusion, with the concentration of 200 microg/kg alpha-MSH, coronary flow, aortic flow and left ventricular developed pressure were significantly improved from their control values of 14.6+/-0.6 ml/min, 7.5+/-0.5 ml/min and 9.1+/-0.4 kPa to 20.2+/-0.4 ml/min (p

Background: Increasing evidence shows that red wine consumption has cardioprotective effects. These effects have been attributed to the polyphenolic compounds in grapes. Objective: We studied the effects of red grape seed proanthocyanidins on the recovery of postischemic function in isolated rat hearts. Design: Two groups of rats were fed different doses of proanthocyanidin-rich extract for 3 wk and another group was untreated and served as controls. The animals were then anesthetized and the hearts were isolated and subjected to 30 min of ischemia followed by 2 h of reperfusion. Coronary effluents were collected during the third minute of reperfusion for measurement of oxygen free radicals by using electron spin resonance spectroscopy. Results: In rats treated with 50 and 100 mg grape seed proanthocyanidins/kg, the incidence of reperfusion-induced ventricular fibrillation was reduced from its control value of 92% to 42% and 25%, respectively (P < 0.05 for both). The incidence of ventricular tachycardia showed the same pattern. In rats treated with 100 mg proanthocyanidins/kg, the recovery of coronary flow, aortic flow, and developed pressure after 60 min of reperfusion was improved by 32% ± 8%, 98% ± 8%, and 37% ± 3%, respectively (P < 0.05 for all) compared with untreated control rats. Electron spin resonance studies indicated that proanthocyanidins significantly inhibited the formation of oxygen free radicals. In rats treated with 100 mg proanthocyanidins/kg, free radical intensity was reduced by 75% ± 7% (P < 0.05) compared with the control rats. Conclusion: Grape seed proanthocyanidins have cardioprotective effects against reperfusion-induced injury via their ability to reduce or remove, directly or indirectly, free radicals in myocardium that is reperfused after ischemia. Am J Clin Nutr

In isolated working rat heart, capsaicin elicited a concentration-dependent constriction of coronary arteries accompanied by decline of all cardiac parameters recorded (heart rate, coronary and aortic flow, left ventricular developed pressure, and first derivative of left ventricular developed pressure). The following evidence suggests that capsaicin-induced changes are mediated by endothelin of neural origin: (1) the capsaicin (10 nM)-evoked decrease in coronary flow resulting in deterioration of cardiac functions was mimicked by endothelin (0.1 nM); (2) the selective endothelin ET(A) receptor antagonist, cyclo (D-alpha-aspartyl-L-propyl-D-valyl-L-leucyl-D-tryptophyl) (1 microM), abolished the cardiac effects provoked by capsaicin (10 nM); (3) reduction of extracellular Ca2+ concentration from 2.4 to 1.2 or 0.6 mM inhibited the cardiac effects of capsaicin (10 nM) but not those induced by endothelin (0.1 nM); (4) perfusion of the heart with 0.1% (v/v) Triton X-100 damaged the endothelium and reversed the enhancement of coronary flow evoked by bethanechol (1 microM), decreased the basal flow, but was without effect on capsaicin-induced coronary constriction; (5) in response to capsaicin challenge (10-100 nM), the endothelin concentration measured in coronary effluent by means of radioimmunoassay increased up to sevenfold but remained unchanged in the presence of 0.6 mM Ca2+; (6) no reduction of coronary flow was induced by capsaicin (100 nM) applied to the heart of rats which were desensitised by capsaicin (150 mg/kg). It is concluded that, in the rat heart, capsaicin acting on VR1 capsaicin receptors elicits a release of endothelin from the sensory nerve terminals.

Capsaicin-induced increases in heart rate and coronary flow were blocked by NG-nitro- l -Arg-methyl ester (30 mM) in Langendorff-perfused guinea-pig hearts. Neither heart rate nor coronary flow changed by capsaicin in hearts from animals made tolerant to the hypotensive effect of 30 μg/kg nitroglycerin by the administration of 50 mg/kg nitroglycerin subcutaneously 4 times a day over 3 days. We conclude that the effector function of sensory nerves may deteriorate in nitrate tolerance.