Impact of the time-to-target rate of urine volume concept on the outcome of acute decompensated heart failure.

BACKGROUND: Early decongestion with diuretics could improve clinical outcomes. This study aimed to examine the impact of the time-to-target rate of urine volume (T2TUV) concept on the outcome of acute decompensated heart failure (ADHF). METHODS: This multicenter retrospective study included 1670 patients with ADHF who received diuretics within 24 h of admission. T2TUV was defined as the time from admission to the rate of urine volume of 100 ml/h. The primary outcomes were in-hospital death, mortality, and re-hospitalization for 1 year. RESULTS: A total of 789 patients met the inclusion criteria (T2TUV on day 1, n = 248; day 2-3, n = 172; no target rate UV, n = 369). In-hospital mortality in the day 1 group was significantly lower (2.7% vs. 5.9% vs. 11.1%; p < 0.001) than that of other groups. The mortality and re-hospitalization for 1 year in the day 1 group was significantly lower (event-free rate: 67.7% vs. 54.1% vs. 56.9%; log-lank p = 0.004) than that of other groups. In multivariate analysis, predictors of T2TUV at day 1 were age (odds ratio [OR]: 1.02, 95% confidence interval [CI]: 1.01-1.04, p = 0.007), previous hospitalized heart failure (OR: 1.47, 95% CI: [1.03-2.12], p = 0.03), N-terminal-pro B type natriuretic peptide per 1000 pg/ml (OR: 1.02, 95% CI: 1.01-1.04, p = 0.007), carperitide (OR: 0.69, 95% CI: 0.48-0.99, p = 0.05), and early administration of tolvaptan (OR: 0.6, 95% CI: 0.42-0.85, p = 0.004). CONCLUSIONS: T2TUV of less than day 1 was associated with lower in-hospital mortality and decreased mortality and re-hospitalization at 1 year.

Predictors of Poor Very Early Diuretic Response and Effectiveness of Early Tolvaptan in Symptomatic Acute Heart Failure.

BACKGROUND: Diuretic response (DR) in patients with symptomatic acute decompensated heart failure (ADHF) has an impact on prognosis. This study aimed to identify predictive factors influencing acute 6 h poor DR and to assess DR after early administration of tolvaptan (TLV). METHODS: This multicenter retrospective study included 1670 patients who were admitted for ADHF and received intravenous furosemide within 1 h of presentation in clinical scenario 1 or 2 defined based on initial systolic blood pressure ≥100 mmHg with severe symptoms (New York Heart Association class III or IV (n = 830). The score for the poor DR factors in the very acute phase was calculated in patients treated with furosemide-only diuretics (n = 439). The DR to TLV administration was also assessed in patients who received an additional dose of TLV within 6 h (n = 391). RESULTS: The time since discharge from the hospital for a previous heart failure < 3 months (odds ratio [OR] 2.78, 95% confidence interval [CI] 1.34-5.83; p = 0.006), loop diuretics at admission (OR 3.05, 95% CI 1.74-5.36; p < 0.0001), and estimated glomerular filtration rate (eGFR) < 45 mL/min/1.73 m2 (OR 2.99, 95% CI 1.58-5.74; p = 0.0007) were independent determinants of poor DR. The frequency of poor DR according to the risk stratification group was low risk (no risk factor), 18.9%; middle risk (one risk factor), 33.1%; and high risk (two to three risk factors), 58.0% (p < 0.0001). All risk groups demonstrated a significantly lower incidence of poor DR with early TLV administration: 10.7% in the early TLV group versus 18.9% in the loop diuretics group (p = 0.09) of the low-risk group; 18.4% versus 33.1% (p = 0.01) in the middle-risk group, and 20.2% versus 58.0% (p < 0.0001) in the high-risk group. CONCLUSION: Early administration of TLV in patients with predicted poor DR contributed to a significant diuretic effect and suppression of worsening renal function.

Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury.

Hyponatraemia is defined as a serum sodium concentration of <135 mEql/L and is the most common electrolyte disturbance in patients with chronic heart failure. We hypothesize that hyponatraemia may induce Ca2+ overload and enhance reactive oxygen species (ROS) production, which will exacerbate myocardial injury more than normonatraemia. We investigated the effect of hyponatraemia on the ability of the heart to recover from ischaemia/reperfusion episodes. Cardiomyocytes were obtained from 1- to 3-day-old Sprague Dawley rats. After isolation, cardiomyocytes were placed in Dulbecco's modified Eagle's medium (DMEM) containing low sodium concentration (110, 120, or 130 mEq/L) or normal sodium concentration (140 mEq/L) for 72 hours. Exposure of cardiomyocytes to each of the low-sodium medium significantly increased both ROS and intracellular Ca2+ levels compared with the exposure to the normal-sodium medium. In vivo, 8-week-old male Sprague Dawley rats were divided into four groups: control group (Con), furosemide group (Fur), low-sodium diet group (Lsd) and both furosemide and low-sodium diet group (Fur + Lsd). The hearts subjected to global ischaemia exhibited considerable decrease in left ventricular developed pressure during reperfusion, and the size of infarcts induced by ischaemia/reperfusion significantly increased in the Fur, Lsd and Fur + Lsd compared with that in the Con. Hyponatraemia aggravates cardiac susceptibility to ischaemia/reperfusion injury by Ca2+ overload and increasing in ROS levels.

A novel validated method for predicting the risk of re-hospitalization for worsening heart failure and the effectiveness of the diuretic upgrading therapy with tolvaptan.

Increased re-hospitalization due to acute decompensated heart failure (ADHF) is a modern issue in cardiology. The aim of this study was to investigate risk factors for re-hospitalization due to worsening heart failure, and the effect of tolvaptan (TLV) on decreasing the number of re-hospitalizations. This was a multicenter, retrospective study. The re-hospitalization factors for 1191 patients with ADHF were investigated; patients receiving continuous administration of TLV when they were discharged from the hospital (n = 194) were analyzed separately. Patients were classified into 5 risk groups based on their calculated Preventing Re-hospitalization with TOLvaptan (Pretol) score. The total number of patients re-hospitalized due to worsening heart failure up to one year after discharge from the hospital was 285 (23.9%). Age ≥80 years, duration since discharge from the hospital after previous heart failure <6 months, diabetes mellitus, hemoglobin <10 g/dl, uric acid >7.2 mg/dl, left ventricular ejection fraction (LVEF) <40%, left atrial volume index (LAVI) >44.7 ml/m2, loop diuretic dose ≥20 mg/day, hematocrit <31.6%, and estimated glomerular filtration rate (eGFR) <50 ml/min/1.73m2 were independent risk factors for re-hospitalization for worsening heart failure. There was a significant reduction in the re-hospitalization rate among TLV treated patients in the Risk 3 group and above. In conclusions, age, duration since previous heart failure, diabetes mellitus, hemoglobin, uric acid, LVEF, LAVI, loop diuretic dose, hematocrit, and eGFR were all independent risk factors for re-hospitalization for worsening heart failure. Long-term administration of TLV significantly decreases the rate of re-hospitalization for worsening heart failure in patients with a Pretol score of 7.

Glucose Fluctuations Aggravate Cardiac Susceptibility to Ischemia/Reperfusion Injury by Modulating MicroRNAs Expression.

BACKGROUND: The influence of glucose fluctuations (GF) on cardiovascular complications of diabetes mellitus (DM) has been attracting much attention. In the present study, whether GF increase susceptibility to ischemia/reperfusion in the heart was investigated. METHODS AND RESULTS: Male rats were randomly assigned to either a control, DM, and DM with GF group. DM was induced by an injection of streptozotocin, and glucose fluctuation was induced by starvation and insulin injection. One sequential program comprised 2 hypoglycemic episodes during 4 days. The isolated hearts were subjected to 20-min ischemia/30-min reperfusion. The infarct size was larger in hearts with GF than those with sustained hyperglycemia. Activities of catalase and superoxide dismutase were decreased, and expressions of NADPH oxidase and thioredoxin-interacting protein were upregulated by GF accompanied by an increase of reactive oxygen species (ROS). Swollen mitochondria with destroyed cristae were observed in diabetic hearts; they were further devastated by GF. Microarray analysis revealed that the expressions of microRNA (miRNA)-200c and miRNA-141 were abundant in those hearts with GF. Overexpression of miRNA-200c and miRNA-141 decreased mitochondrial superoxide dismutase and catalase activities, and increased ROS levels. Meanwhile, knockdown of miRNA-200c and miRNA-141 significantly decreased ROS levels in cardiomyocytes exposed to GF. CONCLUSIONS: GF increased ROS generation and enhanced ischemia/reperfusion injury in the diabetic heart. Upregulated miRNA-200c and miRNA-141 may account for the increased ROS.

Epicardial catheter ablation of ventricular tachycardia in no entry left ventricle: mechanical aortic and mitral valves.

BACKGROUND: In patients with mechanical aortic and mitral valves and left ventricular tachycardia, catheter ablation may be prevented by limited access to the left ventricle. METHODS AND RESULTS: In our series of 6 patients, 2 patients underwent direct surgical ablation and 4 underwent epicardial catheter ablation via a pericardial window. All patients had abnormal low voltage areas with fractionated or delayed isolated potentials on the apical epicardium. Most of the ventricular tachycardias were targeted by pace mapping. Sites with a good pace match or abnormal electrograms were ablated using an irrigated radiofrequency ablation catheter. A microscopic pathological evaluation of the resected tissue from 2 of the open-heart ablation patients revealed dense fibrosis on the epicardium compared with the endocardium, supporting the feasibility of an epicardial ablation for the ventricular tachycardia. CONCLUSIONS: Epicardial catheter ablation of ventricular tachycardia is a potentially useful therapy in patients who have mechanical aortic and mitral valves.

Glucose fluctuations increase the incidence of atrial fibrillation in diabetic rats.

AIMS: We investigated whether glucose fluctuations aggravate cardiac fibrosis and increase the occurrence of atrial fibrillation (AF) in rats with diabetes mellitus (DM). METHODS AND RESULTS: Streptozotocin-induced diabetic rats were randomly divided into three groups: uncontrolled DM (U-STZ) group, controlled DM (C-STZ) group, and DM with glucose fluctuations (STZ-GF) group. Glucose fluctuations were induced by fasting for 24 h and additional regular insulin injections (0.5 IU/kg) administered three times per week for three consecutive weeks. C-STZ rats were administered long acting insulin (20 IU/kg) twice a day to control blood glucose levels. Cardiac fibrosis evaluated by Masson trichrome staining and the expressions of collagen type 1, collagen type 3, and α-smooth muscle actin were increased in U-STZ rats compared with C-STZ rats, which were more pronounced in STZ-GF rats. The inducibility of AF was significantly larger in U-STZ rats than C-STZ rats and was greatest in STZ-GF rats. To explore the mechanism of cardiac fibrosis, we investigated the levels of reactive oxygen species (ROS) and apoptosis. The expression of malondialdehyde, an indicator of ROS levels, was significantly upregulated in STZ-GF rats compared with U-STZ rats, along with increased thioredoxin-interacting protein (Txnip) expression in STZ-GF rats. Furthermore, caspase-3 expression and the number of TUNEL-positive cells were significantly increased in STZ-GF rats compared with U-STZ and C-STZ rats. CONCLUSION: Glucose fluctuations increase the incidence of AF by promoting cardiac fibrosis. Increased ROS levels caused by upregulation of Txnip expression may be a mechanism whereby in glucose fluctuations induce fibrosis.

Production of reactive oxygen species in the diabetic heart. Roles of mitochondria and NADPH oxidase.

Reactive oxygen species (ROS) are the main facilitators of cardiovascular complications in diabetes mellitus (DM), and the ROS level is increased in cultured cells exposed to high glucose concentrations or in diabetic animal models. Emerging evidence shows that mitochondria and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase are dominant mechanisms of ROS production in the diabetic heart. Hyperpolarization of the mitochondrial inner membrane potentials and impaired mitochondrial function promote ROS production in the mitochondria of the diabetic heart. Uncoupling proteins are upregulated and may reduce the ROS level by depolarizing the mitochondrial inner membrane potential. NADPH oxidase is another major site of ROS production and its contribution to DM-induced ROS increase has been elucidated not only in vascular smooth muscle cells and endothelial cells, but also in cardiomyocytes. Protein kinase C, angiotensin II, and advanced glycation endproducts (AGEs)/receptor for AGEs can activate NADPH oxidase. Increased intracellular calcium level mediated via the Na(+)-H(+) exchanger and subsequent activation of Ca(2+)/calmodulin-dependent protein kinase II may also activate NADPH oxidase. This review presents the current understanding of the mechanisms of ROS production, focusing especially on the roles of mitochondria and NADPH oxidase.

Activation of CaMKII as a key regulator of reactive oxygen species production in diabetic rat heart.

Diabetes mellitus is a risk factor for heart failure. Increased reactive oxygen species (ROS) have been proposed as a possible mechanism of cardiac dysfunction in diabetic patients. However, the mechanisms of ROS increase are still elusive. We hypothesized that activation of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) induced by impaired intracellular Ca(2+) ([Ca(2+)](i)) metabolism may stimulate ROS production in the diabetic heart. Cultured cardiomyocytes from neonatal rats were exposed to high glucose concentrations (25 mmol/L) and ROS levels were analyzed in 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H(2)DCFDA)-loaded cells by flow cytometry analysis. Exposure to high glucose concentrations for 24h significantly increased CM-H(2)DCFDA fluorescence, which was significantly inhibited by 1,2-bis (o-aminophenoxy) ethane- N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA-AM), a [Ca(2+)](i) chelator, and KB-R7943, an inhibitor of the Na(+)-Ca(2+) exchanger (NCX) in the reverse mode. These results indicate that [Ca(2+)](i) increase by NCX activation may induce ROS increase following exposure to high glucose concentrations. We confirmed that exposure to high glucose concentrations significantly increased [Ca(2+)](i), which was inhibited by KB-R7943. Na(+)-H(+) exchanger (NHE) is a key factor in [Ca(2+)](i) metabolism, and is known to activate NCX by increasing the intracellular Na(+) ([Na(+)](i)) level. We showed that the expression of NHE isoform 1 and NHE activity increased following exposure to high glucose concentrations by evaluating protein expressions and intracellular pH recovery from acid loading. Exposure to high glucose concentrations up-regulated phosphorylated CaMKII expression in cardiomyocytes that was inhibited by KB-R7943. Further, autocamtide 2-related inhibitory peptide (AIP), a CaMKII inhibitor, significantly attenuated the ROS increase following exposure to high glucose concentrations. We confirmed these results obtained in in vitro experiments in an animal model of diabetes. ROS level and components of NADPH oxidase, p47phox and p67phox were up-regulated in streptozotocin-induced diabetic rat heart, which were attenuated by KN-93, a CaMKII inhibitor. Consistently, expression of phosphorylated CaMKII was increased in the diabetic heart. Activation of CaMKII by impaired [Ca(2+)](i) metabolism may be a mechanism of ROS increase in the heart with diabetes mellitus.

Inhibition of Na⁺-H⁺ exchange as a mechanism of rapid cardioprotection by resveratrol.

BACKGROUND AND PURPOSE Resveratrol is a polyphenol abundantly found in grape skin and red wine. In the present study, we investigated whether resveratrol exerts protective effects against cardiac ischaemia/reperfusion and also explored its mechanisms. EXPERIMENTAL APPROACH Infarct size and functional recovery in rat isolated perfused hearts subjected to no-flow global ischaemia followed by reperfusion were measured. Cultured neonatal rat cardiomyocytes were exposed to H(2)O(2) (100 µmol·L(-1)) to induce cell injury. Intracellular ion concentrations were measured using specific dyes. Western blotting was used to quantify protein expression levels. KEY RESULTS In rat isolated perfused hearts, treatment with resveratrol (20 and 100 µmol·L(-1)) 15 min before ischaemia considerably improved left ventricular functional recovery and infarct size. In cultured neonatal rat cardiomyocytes, resveratrol significantly attenuated the increase in reactive oxygen species (ROS) and loss of mitochondrial inner membrane potential. Resveratrol also suppressed the increase in intracellular concentrations of Na(+) ([Na(+)](i)) and Ca(2+) ([Ca(2+)](i)) after H(2)O(2) application; however, it did not suppress the ouabain-induced [Ca(2+) ](i) increase. By measuring changes in intracellular pH recovery after acidification, we also confirmed that acid-induced activation of the Na(+)-H(+) exchanger (NHE) was prevented by pretreatment with resveratrol. Furthermore, resveratrol inhibited the H(2)O(2)-induced translocation of PKC-α from the cytosol to the cell membrane; this translocation is believed to activate NHE. CONCLUSION AND IMPLICATIONS Resveratrol exerts cardioprotection by reducing ROS and preserving mitochondrial function. The PKC-α-dependent inhibition of NHE and subsequent attenuation of [Ca(2+)](i) overload may be a cardioprotective mechanism.

Cardioprotective effects of pravastatin against lethal ventricular arrhythmias induced by reperfusion in the rat heart.

BACKGROUND: Statins are reported to reduce mortality in patients with coronary artery disease and that mortality benefit might be related to the drugs' antiarrhythmic properties. METHODS AND RESULTS: Male rats were fed with or without pravastatin (0.1 mg·kg⁻¹·day⁻¹) for 7 days, and thereafter subjected to 10 min of ischemia by coronary artery ligation followed by 20 min reperfusion. Treatment with pravastatin reduced the frequency and duration of ventricular tachycardia and fibrillation (VT/VF) and improved the arrhythmia score after reperfusion. To investigate the rapid effects of pravastatin, isolated perfused rat hearts were subjected to 20 min of global ischemia followed by 30 or 60 min of reperfusion. Treatment with pravastatin (10 nmol/L) from 10 min before ischemia shortened the total duration of reperfusion-induced VT/VF. Interestingly, pravastatin administered from the beginning of reperfusion also exerted antiarrhythmic effects. These results indicate that pravastatin exerts antiarrhythmic effects not only with daily oral intake but also when administered just before ischemia or even after ischemia. Intracellular calcium ([Ca²âº](i)) overload and collapse of mitochondrial inner membrane potential (Δψ(m)) are associated with the arrhythmogenesis during ischemia-reperfusion. In cultured cardiomyocytes, pretreatment with pravastatin (10 nmol/L) suppressed [Ca²âº](i) overload and prevented Δψ(m) loss induced by H2O2. CONCLUSIONS: Pravastatin attenuated reperfusion-induced lethal ventricular arrhythmias. Inhibition of [Ca²âº](i) overload and preserving Δψ(m) may be the mechanisms of the observed antiarrhythmic effects of pravastatin.

High-glucose condition reduces cardioprotective effects of insulin against mechanical stress-induced cell injury.

AIMS: Mechanical stress induces cardiomyocyte injury and contributes to the progression of heart failure in patients with hypertension. In this study, we investigated whether insulin exerts cardioprotective effects against mechanical stretching-induced cell injury, and whether the protective effect is influenced by high-glucose condition. MAIN METHODS: Cultured neonatal rat cardiomyocytes were plated on silicone chambers, and the cells were mechanically stretched by 15% to induce cell injury. KEY FINDINGS: Mechanical stretching increased reactive oxygen species (ROS) and decreased mitochondrial inner membrane potential (DeltaPsi(m)), eventually leading to cell death by apoptosis and necrosis. Insulin activated the phosphoinositide 3 (PI3) kinase/Akt pathway and reduced apoptosis and necrosis by suppressing ROS increase and preserving DeltaPsi(m). However, high-glucose condition attenuated the insulin-induced Akt phosphorylation and cardioprotection. To investigate the mechanisms that attenuated the effects of insulin in high-glucose condition, we examined the expression of tensin homologue deleted on chromosome 10 (PTEN), which is a negative regulator of the PI3 kinase/Akt pathway. The expressions of PTEN and phosphorylated PTEN were significantly decreased by insulin, and those effects were attenuated in high-glucose condition. SIGNIFICANCE: The present results suggest that insulin prevents mechanical stress-induced cell injury which otherwise lead to heart failure. Furthermore, we found that high-glucose condition prevented the decrease in PTEN expression and the cardioprotective effects induced by insulin.

Nanoscale spherical architectures fabricated by metal coordination of multiple dipyrrin moieties.

Phenylethynyl-bridged dipyrrin "dimers" have performed ZnII complexation to give coordination polymers, which provided the fluorescent colloidal spherical objects in solution as well as on the substrate according to the spacer units. Using a mixture of THF and water, unique morphologies, such as bell-shaped and "golf ball"-like architectures, were observed.

Image contrast analysis of STM images of self-assembled dioctadecyl chalcogenides on graphite at the liquid-solid interface.

The structures of self-assembled monolayers of dioctadecyl selenide (CH3(CH2)17)2Se and dioctadecyl telluride (CH3(CH2)17)2Te, as well as dioctadecyl ether (CH3(CH2)17)2O and dioctadecyl sulfide (CH3(CH2)17)2S, on graphite at the liquid-solid interface were systematically investigated by scanning tunneling microscopy (STM). Both dioctadecyl selenide and telluride formed monolayer structures in which the tilt angle between the molecular axis of the alkyl chain and the lamellae axis was 90 degrees , while dioctadecyl ether assembled with a tilt angle of 60 degrees . Dioctadecyl sulfide was found to make two different self-assembled structures having tilt angles of 60 and 90 degrees . When selenide was embedded in ether compounds in mixed self-assembled monolayers, the alkyl chains of the selenide became blurred, implying that the alkyl chains in the monolayers were unstable. This is in contrast with the structure of co-adsorbed monolayers of the ether and sulfide compounds, where the images of all alkyl chains had high spatial resolution. For the co-adsorbed monolayers, the image contrast of chalcogen atoms was normalized compared with that of alkyl chains of the ether compound in the same image frame. The normalized image contrast was found to be independent of the measurement conditions involving tip shapes, having the following trend, Te>Se>S>C>O. The difference in the normalized image contrast among chalcogen atoms are discussed based on fundamental parameters like polarizability and atomic radii.