Beneficial effects of trimetazidine treatment on exercise tolerance and B-type natriuretic peptide and troponin T plasma levels in patients with stable ischemic cardiomyopathy.

BACKGROUND: In patients with ischemic cardiomyopathy, mortality rate and quality of life are unsatisfactory. We investigated the effects of the metabolic agent trimetazidine (TMZ) on exercise tolerance and prognostic markers B-type natriuretic peptide (BNP) and cardiac troponin T (cTnT) plasma levels. METHODS: Fifty patients with ischemic cardiomyopathy were randomized either to receive TMZ (20 mg, TID) in addition to their conventional treatment (TMZ group, n = 25) or to continue their usual drug therapy (control group, n = 25) for 6 months. Patients were evaluated at baseline, at 1 month, and at 6 months (echocardiography and 6-minute walking test). At enrollment and at the end of follow-up, blood testing was performed for determination of BNP and cTnT plasma levels. RESULTS: After 6 months, no significant New York Heart Association class changes occurred in all patients (P = NS). In the TMZ group, a significant increase of exercise tolerance (P < .01) was detected, whereas left ventricular ejection fraction was unchanged (28% +/- 4%, 29% +/- 5%, and 32% +/- 5% at baseline, at 1 month, and at 6 months, respectively; P = NS). In the TMZ group, BNP was significantly reduced (6 months, 135 +/- 22 vs 252 +/- 44 pg/mL; P < .001), whereas it was significantly increased in controls (6 months, 288 +/- 46 vs 239 +/- 59 pg/mL; P < .02); cTnT significantly (P < .001) reduced during TMZ treatment, whereas it was unchanged in the control group. CONCLUSIONS: Six-month TMZ treatment improves exercise tolerance and reduces plasma levels of BNP and cTnT in patients with compensated ischemic cardiomyopathy.

Chronic treatment with rosuvastatin modulates nitric oxide synthase expression and reduces ischemia-reperfusion injury in rat hearts.

OBJECTIVE: Due to reported modulatory effects of statins on nitric oxide synthase (NOS) expression, we tested the hypothesis of protective effects of in vivo chronic treatment with rosuvastatin, a novel 3-hydroxy-3-methyl-glutaryl coenzyme A-reductase inhibitor, on ischemia-reperfusion injury, and investigated mechanisms involved. METHODS: After 3 weeks of in vivo treatment with rosuvastatin (0.2-20 mg/kg/day) or placebo, excised hearts from Wistar rats were subjected to 15 min global ischemia and 22-180 min reperfusion. We evaluated creatine-phosphokinase and nitrite levels in the coronary effluent, heart weight changes, microvascular permeability (extravasation of fluoresceine-labeled albumin), ultrastructural alterations, and the expression of endothelial (e) and inducible (i) nitric oxide synthase (NOS) (by reverse-transcription polymerase chain reaction and Western blotting). RESULTS: Rosuvastatin 0.2 and 2 mg/kg/day significantly reduced myocardial damage and vascular hyperpermeability, concomitant with a reduction in endothelial and cardiomyocyte lesions. At 2 mg/kg/day, rosuvastatin significantly increased eNOS mRNA and protein compared with untreated hearts, and conversely decreased iNOS mRNA and protein, as well as nitrite production after ischemia-reperfusion. The addition of the NOS inhibitor N(omega)-nitro-L-arginine methylester (L-NAME, 30 micromol/L) significantly reduced cardioprotection against ischemia-reperfusion. CONCLUSIONS: Chronic treatment with rosuvastatin before ischemia reduces ischemia-reperfusion injury and prevents coronary endothelial cell and cardiomyocyte damage by NO-dependent mechanisms.

Left ventricular wall stress as a direct correlate of cardiomyocyte apoptosis in patients with severe dilated cardiomyopathy.

BACKGROUND: Apoptosis has been implicated as a possible mechanism in the development of heart failure (HF), but the mechanisms involved remain unclear. In patients with severe dilated cardiomyopathy, we evaluated cardiomyocyte apoptosis in relation to the transmural distribution of Bax and Bcl-2 proteins (2 molecules inhibiting or promoting apoptosis, respectively) and left ventricular wall stresses. METHODS: We studied the presence and distribution of cardiomyocyte apoptosis in 90 tissue samples obtained from 8 patients who were undergoing left ventricular reduction with the Batista (ventricular remodeling) operation. Apoptosis was assessed in tissue samples taken from the entire left ventricular thickness (subdivided in subepicardial, midmyocardial, and subendocardial sections) with the terminal deoxynucleotidyl transferase mediated dUTP-biotin nick-end labeling (TUNEL) technique and DNA agarose gel electrophoresis. The expression of Bcl-2 and Bax proteins were determined with both Western analysis and immunohistochemistry. RESULTS: TUNEL-positive cells (apoptotic index) were 2.3% +/- 1.4%. Apoptotic cells were predominantly distributed in the subendocardium, where higher levels of Bax protein were detected. The ratio of Bax to Bcl-2 proteins (Bax/Bcl-2) was similar in the midmyocardium or subepicardium, but increased in the subendocardium, where it was directly related to systolic wall stress (y = 0.009x - 0.629; r2 = 0.85, P <.001). The apoptotic index was also directly related to systolic and end-diastolic stresses calculated from hemodynamic and echocardiographic data (r2 = 0.77, P <.001 and r2 = 0.40, P <.01, respectively). CONCLUSIONS: In patients with dilated cardiomyopathy, in whom cardiomyocyte apoptosis is an important cause of cell loss, apoptosis is more extensively localized in the subendocardium and strictly related to ventricular wall stresses and the Bax/Bcl-2 ratio.

Effect of chronic hypoxia on inducible nitric oxide synthase expression in rat myocardial tissue.

The purpose of our study was to evaluate the effect of chronic exposure to low cellular oxygen tension (90% N2 and 10% O2 for 14 days) in inducing apoptosis and activation of transcription and translation of inducible nitric oxide (NO) synthase (iNOS) in rat hearts tissue. Rats were divided into four groups: normoxic, hypoxic, rats maintained in normoxic condition for 7 days and subjected to hypoxic conditions for another 7 days, and rats maintained in hypoxic condition for 7 days and subjected to normoxic conditions for another 7 days. At the 7th and 14th days, five rats from each group were sacrificed. Immunohistochemical and Western blot analysis were performed on myocardial tissue to reveal the presence of iNOS. Expression of iNOS was determined by RT-PCR. Apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling and by detection of internucleosomal DNA fragmentation by electrophoresis. Electrophoretic analysis of DNA showed oligonucleosomal fragmentation in the hypoxic groups, but no ladder was observed in the other groups. This data was confirmed through end labeling with streptavidin-biotin (biotin d-UTP). iNOS expression was evaluated through immunohistochemical techniques (Ab anti-iNOS) and Western blotting, and the results were quantified with a computerized imaging analysis. The expression of iNOS protein was greater in the hypoxic groups; in the normoxic groups, only a nonspecific background was detected. This data was supported with results obtained through RT-PCR, which showed the specific transcription of mRNA for iNOS in the same experimental conditions. In addition, the iNOS activity was also evaluated and was found to be more active in the hypoxic groups (0.1 +/- 0.01 vs 0.02 +/- 0.003). The present study shows that exposure to low oxygen tension is capable of inducing programmed cell death and activating iNOS.

Inducible nitric oxide synthase and heme oxygenase-1 in rat heart: direct effect of chronic exposure to hypoxia.

Hypoxia is a potent regulator of various biological process. Mammalian cells respond to hypoxia by increased expression of several genes. The aim of this study was to evaluate the effects of chronic exposure to low oxygen tension on the induction of inducible nitric oxide synthase (iNOS) and heme oxygenase-1 (HO-1) in rat heart. Male Wistar rats were assigned randomly to 4 groups: (A) control rats maintained in normoxic conditions for 7 and 14 days; (B) rats maintained in hypoxic conditions for 7 and 14 days; (C) rats maintained in normoxic conditions for 7 days and then transferred to hypoxic conditions for 7 days; and (D) rats maintained in hypoxic conditions for 7 days and then transferred to normoxic conditions for 7 days. In Group A, iNOS and HO-1 immunoreactivities were not evident; in Group B these immunoreactivities increased from day 7 to 14; in Group C the immunoreactivities decreased on day 7, compared to day 14; and in Group D, the immunoreactivities increased on day 7, compared to day 14. These findings were confirmed by Western blot analyses of the respective proteins and by rt-PCR assays of the corresponding mRNAs. The results indicate that the adaptive response to hypoxia involves up-regulation of HO-1 through iNOS activation in cardiac cells. HO-1 helps to regulate vascular tone via CO and thereby participates in an important cardiac defense mechanism.

[Trimetazidine and cardioprotection during ischemia-reperfusion]. / Trimetazidina e cardioprotezione durante ischemia-riperfusione.

Although early reperfusion of ischemic myocardium is now considered to be the only intervention able to restore the various cellular functions altered by ischemia and to prevent progression toward cell death of myocardial cells due to necrosis or apoptosis, reperfusion is accompanied by various manifestations grouped under the heading of reperfusion damage or reperfusion syndrome. Functional recovery is therefore not immediate, but usually appears after a certain delay following a period of contractile dysfunction (myocardial stunning) lasting for several hours or even days after the start of reperfusion. The cellular mechanisms underlying the reperfusion damage may involve cellular calcium overload, over-production of oxygen-derived free radicals, cellular acidosis, inflammatory reaction, and microcirculatory dysfunction. Numerous pharmacological studies have been conducted to limit such reperfusion injury and, consequently, prevent stunning and/or reperfusion-induced arrhythmias. A number of experimental and clinical studies have demonstrated the beneficial effects of trimetazidine, a drug that inhibits the long-chain mitochondrial 3-ketoacyl coenzyme A thiolase enzyme in the myocyte, resulting in a shift from fatty acid oxidation to glucose oxidation. This optimization of cardiac metabolism results in direct anti-ischemic effects, limiting calcium accumulation and acidosis, inflammation and oxygen free radical production, and improvement of coronary microcirculation following reperfusion. This agent appears to be particularly promising clinically in the treatment of reperfusion injury, for example in combination with reperfusion strategies during the acute phase of myocardial ischemia or infarction, or in the reduction of the pro-remodeling effects of ischemia in patients with chronic ischemic syndrome and left ventricular dysfunction.

Effect of partial fatty acid oxidation inhibition with trimetazidine on mortality and morbidity in heart failure: results from an international multicentre retrospective cohort study.

OBJECTIVES: The aim of this cohort study was to retrospectively evaluate, in patients with chronic heart failure (CHF), the long term effect of trimetazidine (TMZ) on morbidity and mortality. BACKGROUND: Previous small studies in patients with CHF have shown that TMZ can improve left ventricular function, exercise capacity and NYHA class compared to placebo. However, no data on the effects of TMZ on survival in patients with CHF have ever been produced. METHODS: In this international multicentre retrospective cohort study data from 669 patients were analyzed. 362 patients were on TMZ due to symptom persistence despite up-titration of optimal CHF therapy, while the remaining patients continued conventional CHF therapy alone. Propensity score analysis was performed in order to minimize selection bias between the two groups. RESULTS: Kaplan-Meier analysis for global mortality showed 11.3% improved global survival (p=0.015) and 8.5% improved survival for cardiovascular (CVD) death (p=0.050) in the TMZ group. Cox regression analysis for global mortality showed a significant risk reduction for TMZ treated patients with a hazard ratio (HR)=0.189 (confidence interval - CI 95%: 0.017-0.454; p=0.0002). TMZ also showed a good risk reduction profile for CVD death causes (HR=0.072, CI 95%: 0.019-0.268, p=0.0001). The rate of hospitalization for cardiovascular causes was reduced by 10.4% at 5 years (p<0.0005) with increased hospitalization-free survival of 7.8 months. CONCLUSION: TMZ is effective in reducing mortality and event-free survival in patients with CHF. The addition of TMZ on top of optimal medical therapy improves long term survival in CHF patients.

Energy metabolism in the normal and in the diabetic heart.

Cardiovascular disease is a major health problem all over the world. The prevalence of type 2 diabetes mellitus has been rapidly increasing, together with the risk of cardiovascular events. Patients with diabetes, and/or with insulin resistance as well, have an impaired myocardial metabolism of glucose and free fatty acids (FFA) and accelerated and diffuse atherogenesis, with involvement of coronary artery tree. Significant metabolic alterations at heart level in diabetic patients are the decreased utilization of glucose and the increase in muscular and myocardial FFA uptake and oxidation, occurring as a consequence of the mismatch between blood supply and cardiac metabolic requirements. These metabolic changes are responsible both for the increased susceptibility of the diabetic heart to myocardial ischemia and for a greater decrease of myocardial performance for a given amount of ischemia, compared to non diabetic hearts. A therapeutic approach aimed at an improvement of cardiac metabolism, through manipulations of the utilization of metabolic substrates, may improve myocardial ischemia and left ventricular function. Modulation of myocardial FFA metabolism, in addition to optimal medical therapy, should be the key target for metabolic interventions in patients with coronary artery disease and diabetes. In diabetic patients with ischemic heart disease, the effects of modulation of FFA metabolism could even give greater benefit than in nondiabetic patients.

Trimetazidine improves post-ischemic recovery by preserving endothelial nitric oxide synthase expression in isolated working rat hearts.

OBJECTIVE: Previous investigations have consistently shown that the piperazine derivative trimetazidine (TMZ, 1-[2,3,4-trimethoxybenzil] piperazine, dihydrocloride) has cardioprotective effects in the experimental ischemia-reperfusion model. We tested the hypothesis that cardioprotective effect of TMZ is partly mediated by preservation of the endothelial barrier of the coronary microcirculation. METHODS: Isolated Wistar rat (250-300 g) hearts were subjected to a 15 min period of global ischemia and 180 min reperfusion in the presence or absence of 1 microM TMZ. Hemodynamic parameters, heart weight, creatinekinase (CK) release and microvascular permeability (FITC-albumin extravasation) were evaluated. In addition, eNOS gene expression was estimated by rt-PCR, and eNOS protein levels were assessed by Western analysis. In order to confirm the involvement of NO in mediating the cardioprotective effects of TMZ, 30 microM N(omega)-nitro-l-arginine methylester (L-NAME), a specific inhibitor of nitric oxide synthase, was used. RESULTS: After ischemia and reperfusion, TMZ produced a significant improvement of mechanical function associated with a reduction of CK release and FITC-albumin diffusion (P<0.001); the agent also resulted in improvement in coronary flow (at 45 min+27% vs control). The eNOS mRNA and protein levels were significantly higher in TMZ-treated hearts compared to controls. The addition of L-NAME significantly reduced the beneficial effects of TMZ on contractile function, CK release and FITC-albumin diffusion. CONCLUSIONS: in the isolated rat heart, TMZ exerts a relevant, NO-dependent, cardioprotection against ischemia-reperfusion injury and preserves the endothelial barrier of the coronary circulation. This could contribute to explain the cardioprotective action of TMZ following ischemia and reperfusion.

Trimetazidine and reduction in mortality and hospitalization in patients with ischemic dilated cardiomyopathy: a post hoc analysis of the Villa Pini d'Abruzzo Trimetazidine Trial.

The goal of this study was to determine the effects of trimetazidine on all-cause mortality and heart failure hospitalizations in patients with ischemic cardiomyopathy. We performed an extension to 48 months and a post-hoc analysis of the Villa Pini d'Abruzzo trimetazidine trial; in this single-center, open-label, randomized trial with the metabolic inhibitor trimetazidine in chronic heart failure, 61 patients were randomized to either receive trimetazidine (20 mg tid) in addition to their conventional treatment or to continue their usual drug therapy for 4 years. Patients were evaluated at baseline and at 6, 12, 18, 24, 32, 36, 42, and 48 months with clinical examination, echocardiography, and 6-minute walking test. Trimetazidine added to usual treatment significantly reduces all-cause mortality (-56%; hazard ratio, 0.258; 95% CI, 0.097 to 0.687; log-rank test, P = 0.0047), heart failure hospitalization (-47%; log-rank test, P = 0.002), and improves patient functional status (NYHA class and 6-min walking test). In trimetazidine-treated patients, a significant increase of the left ventricle ejection fraction was also detected (LVEF P < 0.001 at 48 months). It is therefore concluded that long-term trimetazidine significantly reduces all-cause mortality and heart failure hospitalization in patients with ischemic cardiomyopathy. If confirmed in large-scale randomized trials, this treatment could be useful in the management of left ventricle dysfunction and remodeling in patients with ischemic heart disease.

Simvastatin attenuates expression of cytokine-inducible nitric-oxide synthase in embryonic cardiac myoblasts.

Cardiac stem cells or myoblasts are vulnerable to inflammatory stimulation in hearts with infarction or ischemic injury. Widely used for the prevention and treatment of atherosclerotic heart disease, the cholesterol-lowering drugs statins may exert anti-inflammatory effects. In this study, we examined the impact of inhibition of hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase with simvastatin on the expression of inducible nitric-oxide synthase (iNOS) in embryonic cardiac myoblasts stimulated with the proinflammatory cytokines, interleukin-1 or tumor necrosis factor. Treatment with simvastatin significantly reduced the levels of iNOS mRNA and protein in cytokine-treated rat H9c2 cardiac embryonic myoblasts. Addition of the HMG-CoA reductase product, L-mevalonate, and the by-product of cholesterol synthesis, geranylgeranyl pyrophosphate, could reverse the statin inhibitory effect on iNOS expression. Simvastatin treatment lowered the Rho GTPase activities, whereas the Rho-associated kinase inhibitor Y27632 partially blocked the statin inhibitory effect on nitrite production in the cytokine-treated H9c2 cells. Treatment with simvastatin led to inactivation of NF-kappaB by elevation of the NF-kappaB inhibitor IkappaB and reduction of the NF-kappaB nuclear contents in the cytokine-stimulated H9c2 cells. Hence, treatment with simvastatin can attenuate iNOS expression and NO synthesis in cytokine-stimulated embryonic cardiac myoblasts. The statin inhibitory effect may occur through isoprenoid-mediated intracellular signal transduction, which involves several key signal proteins, such as Rho kinase and IkappaB/NF-kappaB. These data suggest that statin therapy may protect the cardiac myocyte progenitors against the cytotoxicity of cytokine-induced high output of NO production in infarcted or ischemic hearts with inflammation.