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Objective: To assess the impact of intermediate-term treatment with rosiglitazone on high-sensitivity cardiac troponin T levels among patients with type 2 diabetes mellitus with or at high risk of coronary artery disease. Methods: High-sensitivity cardiac troponin T level was measured at baseline and after 6 months of study treatment in a randomized trial comparing rosiglitazone versus placebo in patients with type 2 diabetes and prevalent cardiovascular disease or multiple cardiovascular disease risk factors. Univariable and multivariable linear regression analyses were performed to assess the effect of rosiglitazone versus placebo on high-sensitivity cardiac troponin T levels. Results: The study included 150 randomized participants, of whom 106 had paired baseline and end-of-study blood samples for analysis (mean age: 56 ± 8 years, 42% women; 8.8 years average type 2 diabetes duration; mean haemoglobin A1c of 7.5). Almost all study participants (93%) had detectable high-sensitivity cardiac troponin T (⩾3 ng/L) at baseline, including 23% with high-sensitivity cardiac troponin T levels exceeding the threshold commonly used to diagnose myocardial infarction (⩾14 ng/L). Change in high-sensitivity cardiac troponin T levels from baseline to follow-up was not significantly different between rosiglitazone and placebo groups (p = 0.316). Conclusion: Rosiglitazone did not impact high-sensitivity cardiac troponin T levels, adding to the growing body of literature suggesting that the incremental heart failure risk associated with rosiglitazone is not mediated by direct myocardial injury. [ABSTRACT FROM AUTHOR]

Objectives: This paper examined whether nebivolol protects the heart via nitric oxide (NO) synthase and NO-dependent signaling in an in vivo model of acute myocardial infarction. Background: Beta3-adrenergic receptor (AR) activation promotes endothelial nitric oxide synthase (eNOS) activity and NO bioavailability. We hypothesized that specific beta3-AR agonists would attenuate myocardial ischemia-reperfusion (MI/R) injury via eNOS activation and increased NO bioavailability. Methods: Mice were subjected to 45 min of myocardial ischemia in vivo followed by 24 h of reperfusion (R). Nebivolol (500 ng/kg), CL 316243 (1 μg/kg), BRL-37344 (1 μg/kg), or vehicle (VEH) was administered at the time of R. Myocardial area-at-risk (AAR) and infarct size (INF)/AAR was measured at 24 h of R. Cardiac tissue and plasma were collected to evaluate eNOS phosphorylation, neuronal nitric oxide synthase (nNOS), inducible nitric oxide synthase expression, and nitrite and nitrosothiol levels. Results: Nebivolol (500 ng/kg) reduced INF/AAR by 37% (p < 0.001 vs. VEH) and serum troponin-I levels from 41 ± 4 ng/ml to 25 ± 4 ng/ml (p < 0.05 vs. VEH). CL 316243 and BRL-37344 reduced INF by 39% and 42%, respectively (p < 0.001 vs. VEH). Nebivolol and CL 316243 increased eNOS phosphorylation at Ser-1177 (p < 0.05 vs. VEH) and increased nitrite and total nitrosylated protein levels. Nebivolol and CL 316243 significantly increased myocardial nNOS expression. Nebivolol failed to reduce INF after MI/R in beta3-AR −/−, eNOS−/−, and in nNOS−/− mice. Conclusions: Our results indicate that beta3-AR agonists protect against MI/R injury. Furthermore, the cardioprotective effects of beta3-AR agonists are mediated by rapid eNOS and nNOS activation and increased NO bioavailability. [Copyright &y& Elsevier]

Diallyl trisulfide (DATS), a polysulfide constituent found in garlic oil, is capable of the release of hydrogen sulfide (H(2)S). H(2)S is a known cardioprotective agent that protects the heart via antioxidant, antiapoptotic, anti-inflammatory, and mitochondrial actions. Here, we investigated DATS as a stable donor of H(2)S during myocardial ischemia-reperfusion (MI/R) injury in vivo. We investigated endogenous H(2)S levels, infarct size, postischemic left ventricular function, mitochondrial respiration and coupling, endothelial nitric oxide (NO) synthase (eNOS) activation, and nuclear E2-related factor (Nrf2) translocation after DATS treatment. Mice were anesthetized and subjected to a surgical model of MI/R injury with and without DATS treatment (200 μg/kg). Both circulating and myocardial H(2)S levels were determined using chemiluminescent gas chromatography. Infarct size was measured after 45 min of ischemia and 24 h of reperfusion. Troponin I release was measured at 2, 4, and 24 h after reperfusion. Cardiac function was measured at baseline and 72 h after reperfusion by echocardiography. Cardiac mitochondria were isolated after MI/R, and mitochondrial respiration was investigated. NO metabolites, eNOS phosphorylation, and Nrf2 translocation were determined 30 min and 2 h after DATS administration. Myocardial H(2)S levels markedly decreased after I/R injury but were rescued by DATS treatment (P < 0.05). DATS administration significantly reduced infarct size per area at risk and per left ventricular area compared with control (P < 0.001) as well as circulating troponin I levels at 4 and 24 h (P < 0.05). Myocardial contractile function was significantly better in DATS-treated hearts compared with vehicle treatment (P < 0.05) 72 h after reperfusion. DATS reduced mitochondrial respiration in a concentration-dependent manner and significantly improved mitochondrial coupling after reperfusion (P < 0.01). DATS activated eNOS (P < 0.05) and increased NO metabolites (P < 0.05). DATS did not appear to significantly induce the Nrf2 pathway. Taken together, these data suggest that DATS is a donor of H(2)S that can be used as a cardioprotective agent to treat MI/R injury.