Tomoo Furumoto

Angiotensin-Converting Enzyme Inhibition Attenuates Hypofibrinolysis and Reduces Cardiac Perivascular Fibrosis in Genetically Obese Diabetic Mice

Background—Obesity and insulin resistance are associated with accelerated macrovascular and microvascular coronary disease, cardiomyopathic phenomena, and increased concentrations and activity in blood of plasminogen activator inhibitor type 1 (PAI-1), the primary physiological inhibitor of fibrinolysis. Methods and Results—To determine whether hypofibrinolysis in blood and tissues and its potential sequelae could be attenuated pharmacologically, we studied genetically modified obese mice. By 10 weeks of age, obese mice exhibited increases in left ventricular weight and glucose and immunoreactive insulin in blood. PAI-1 activity in blood measured spectrophotometrically was significantly elevated as well. The difference compared with values in lean controls widened by 20 weeks of age. Perivascular fibrosis in coronary arterioles and small coronary arteries was evident in obese mice 10 and 20 weeks of age, paralleling increases in PAI-1 and tissue factor expression evident by immunohistochemical image analysis, in situ hybridization, and reverse transcription-polymerase chain reaction. Inhibition of ACE activity initiated in obese mice 10 weeks of age and continued for 20 weeks arrested the increase in PAI-1 activity in blood and in cardiac PAI-1 and tissue factor mRNA as well as coronary perivascular fibrosis. Conclusions—Thus, inhibition of proteo(fibrino)lysis and augmented tissue factor expression in the heart precede and may contribute to the coronary perivascular fibrosis seen with obesity and insulin resistance. Furthermore, inhibition of ACE activity can attenuate all 3 phenomena.

Plasma Interleukin-6 and Tumor Necrosis Factor-α Can Predict Coronary Endothelial Dysfunction in Hypertensive Patients

Coronary endothelial function is impaired in hypertension; however, the severity of this impairment varies among patients. We aimed to identify the predictors of coronary endothelial dysfunction among clinical variables related to hypertension and atherosclerosis. Twenty-seven untreated, uncomplicated essential hypertensive patients and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using 15O-water positron emission tomography (PET) at rest and during a cold pressor test (CPT). Coronary vascular resistance (CVR) during CPT was used as a marker of coronary endothelial function. Serum low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, malondialdehyde-LDL, homeostasis model assessment, high-sensitivity C-reactive protein (hs-CRP), and plasma interleukin-6 (IL-6) and tumor necrosis factor (TNF)-α were also measured. CVR during CPT was significantly higher in hypertensive patients than in healthy controls (114±26 vs. 94±12 mmHg/[mL/g/min]; p<0.05). By univariate analysis, CVR during CPT was correlated with LDL cholesterol (r=0.38, p<0.05), IL-6 (r=0.46, p<0.02), and TNF-α (r=0.39, p<0.05) in hypertensive patients. By multivariate analysis, IL-6 and TNF-α were significant independent predictors of CVR during CPT. Elevated plasma IL-6 and TNF-α levels were independent predictors of coronary endothelial dysfunction in hypertensive patients. These results suggest that plasma IL-6 and TNF-α might be useful for identifying the high risk subgroup of hypertensive patients with coronary endothelial dysfunction and provide an important clue to link systemic inflammation to the development of coronary atherosclerosis.

Hyperuricemia predicts adverse outcomes in patients with heart failure.

BACKGROUND Hyperuricemia is associated with worse outcomes of patients with chronic heart failure (HF). However, it is unknown in an unselected HF patients encountered in routine clinical practice. We thus assessed the impact of hyperuricemia on long-term outcomes including mortality and rehospitalization among patients hospitalized with worsening HF. METHODS The Japanese Cardiac Registry of Heart Failure in Cardiology (JCARE-CARD) studied prospectively the characteristics and treatments in a broad sample of hospitalized HF patients and the outcomes were followed for 2.1 years after discharge. Study cohorts (n=1869) were divided into 2 groups according to serum uric acid (UA) at discharge; ≥ 7.4 mg/dL (n=908) and <7.4 mg/dL (n=961). RESULTS Of the total cohort of HF patients, 56% had hyperuricemia defined as UA ≥ 7.0mg/dl. Patients with UA ≥ 7.4 mg/dL had higher rates of all-cause death, cardiac death, rehospitalization, and all-cause death or rehospitalization due to worsening HF. After multivariable adjustment, higher UA levels were a significant and independent predictor for all-cause death (adjusted hazard ratio [HR] 1.413, 95% confidence interval [CI] 1.094-1.824, P=0.008) and cardiac death (adjusted HR 1.399, 95% CI 1.020-1.920, P=0.037). CONCLUSIONS Hyperuricemia was common in patients with HF encountered in clinical practice and higher UA was independently associated with long-term adverse outcomes in these patients.

Induction of Plasminogen Activator Inhibitor-1 in Endothelial Cells by Basic Fibroblast Growth Factor and Its Modulation by Fibric Acid

Plasminogen activator inhibitor-1 (PAI-1) inhibits fibrinolysis and proteolysis. Basic fibroblast growth factor (bFGF) stimulates angiogenesis, which requires regional proteolysis. Because modulation of vasculopathy requires tight control of proteolysis, effects of bFGF on PAI-1 expression in endothelial cells (ECs) were characterized. bFGF increased PAI-1 mRNA and accumulation of PAI-1 protein in conditioned media in human umbilical vein ECs. The bFGF-mediated increase in PAI-1 mRNA was attenuated by inhibition of extracellular signal-regulated kinase kinase in human ECV304 cells. The rate of decrease in PAI-1 mRNA after actinomycin D treatment was not affected by bFGF. Transient transfection assays of the human PAI-1 promoter-luciferase construct demonstrated that bFGF-induced PAI-1 transcription was dependent on the elements within the −313 to −260 bp relative to the transcription start site. This region contains an E26 transformation specific 1 (Ets-1)-like site. Electrophoretic mobility shift assay showed that bFGF increased nuclear translocation or DNA binding of the Ets-1-like transcription factor to the PAI-1 promoter. Nucleotide substitution to disrupt the Ets-1-like site reduced bFGF-stimulated promoter activity. Fenofibric acid, an agonist ligand for the peroxisome proliferator-activated receptor-&agr;, inhibited basal and bFGF-stimulated PAI-1 expression. By inducing PAI-1 expression from ECs, bFGF may control proteolysis and fibrinolysis in vessel walls.

Interleukin-6 and Mevastatin Regulate Plasminogen Activator Inhibitor-1 Through CCAAT/Enhancer-Binding Protein-δ

Objective—We sought to determine the etiologic mechanism of proinflammatory cytokine, interleukin-6 (IL-6), and statin as regulators of synthesis of plasminogen activator inhibitor-1 (PAI-1), the physiological fibrinolysis inhibitor and an acute-phase reactant. Methods and Results—Transient transfection and luciferase assay in HepG2 human hepatoma-derived cells demonstrated that IL-6 increased PAI-1 promoter activity and mevastatin decreased IL-6–inducible response. Systematic deletion assay of the promoter demonstrated that the region (−239 to −210 bp) containing a putative CCAAT/enhancer-binding protein (C/EBP) binding site was necessary. Point mutation in this site abolished the IL-6–inducible response. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that C/EBPα, C/EBPβ, and C/EBP&dgr; were involved in protein–DNA complex formation in intact cells. Deoxyribonuclease (DNase) I footprinting analysis revealed that 5′ flanking region (−232 to −210 bp) is acute-phase response protein-binding site. C/EBP&dgr; binding activity was increased by IL-6 and attenuated by mevastatin. Mevastatin attenuated IL-6–mediated increase of C/EBP&dgr; protein in the nuclear extracts. IL-6 also increased PAI-1 and C/EBP&dgr; mRNA in mouse primary hepatocytes. Conclusions—IL-6 increases hepatic PAI-1 expression mediated by the −232- to −210-bp region of the promoter containing a C/EBP&dgr; binding site. Vascular protection by statins may be partly mediated through regulation of CEBP&dgr; and consequent modulation of PAI-1 expression.

Increased plasma sphingosine-1-phosphate in obese individuals and its capacity to increase the expression of plasminogen activator inhibitor-1 in adipocytes.

ObjectivesConcentrations of plasminogen activator inhibitor-1 (PAI-1) are increased in obese individuals. One source of PAI-1 is adipocytes. Hypoxia develops within adipose tissue as it expands, presumably contributing to increased levels of sphingosine-1-phosphate (S1P). S1P is a breakdown product of sphingosine, ubiquitous in cell membranes. We have shown previously that S1P increases the expression of PAI-1 in human liver-derived cell line. In the present study, we aimed to determine whether hypoxia induces S1P in adipocytes, thereby potentially contributing to an increase in PAI-1 and hence constraints on fibrinolysis associated with obesity. Materials and methodsMouse 3T3-L1 adipocytes were exposed to CoCl2 to simulate hypoxia. Assays were performed for PAI-1 mRNA (quantitative PCR) and S1P (high-performance liquid chromatography). ResultsThe physiologic concentration of S1P increased PAI-1 mRNA expression. The S1P2 receptor antagonist attenuated the increase in PAI-1. Adipocytes expressed sphingosine kinase 1/2 (SPHK1/2) and S1P lyase, key enzymes involved in S1P production and degradation. Hypoxia increased SPHK activity and decreased S1P lyase mRNA. Hypoxia reduced cytosolic sphingosine and increased S1P release into conditioned medium. Inhibitors of ABCA1 and ABCC1 reduced the release of S1P into conditioned media. In obese patients with uncomplicated dyslipidemia and hypertension, plasma S1P was increased compared with that in nonobese and lean individuals. ConclusionHypoxia in adipose tissue of obesity can promote elaboration of S1P that binds to S1P2 receptors in an autocrine or a paracrine manner. S1P potentially contributes toward increased expression of PAI-1 and consequent constraints on fibrinolysis. S1P production and extracellular transport provide an attractive target for therapy to attenuate impaired fibrinolysis associated with obesity.

Hepatocyte Growth Factor Regulates E Box–Dependent Plasminogen Activator Inhibitor Type 1 Gene Expression in HepG2 Liver Cells

Objective—We sought to determine the etiologic mechanism of pleiotropic growth factor, hepatocyte growth factor (HGF), as a regulator of hepatic synthesis of plasminogen activator inhibitor (PAI)-1, the physiological inhibitor of fibrinolysis and a potential inducer of atherothrombosis. Methods and Results—HGF increased PAI-1 mRNA expression and PAI-1 protein accumulation in the conditioned media of human liver-derived HepG2 cells, and increased hepatic PAI-1 mRNA expression in vivo in mice. HGF-inducible PAI-1 mRNA was attenuated by U0126, a specific inhibitor of mitogen-activated protein kinase (MAPK) kinase, and genistein, an inhibitor of tyrosine kinase. HGF increased the human PAI-1 promoter (−829 to +36 bp) activity, and deletion and mutation analysis uncovered a functional E box (5′-CACATG-3′) at positions −158 to −153 bp. Electrophoretic mobility shift assays demonstrated that this E box binds upstream stimulatory factors (USFs). HGF phosphorylated USFs through MAPK and tyrosine kinase pathways. Co-transfection of USF1 expression vector increased PAI-1 promoter activity. Sterol regulatory element-binding protein-1 attenuated HGF-inducible PAI-1 promoter activity. Conclusions—Because USFs are involved in the regulation of carbohydrates and lipid metabolism, HGF-mediated PAI-1 production may provide a novel link between atherothrombosis and metabolic derangements. Targeting HGF signaling pathway may modulate the thrombotic risk in high-risk patients.

Single-slice epicardial fat area measurement: do we need to measure the total epicardial fat volume?

PurposeThe aim of this study was to assess a method for measuring epicardial fat volume (EFV) by means of a single-slice area measurement. We investigated the relation between a single-slice fat area measurement and total EFV.Methods and methodsA series of 72 consecutive patients (ages 65 ± 11 years; 36 men) who had undergone cardiac computed tomography (CT) on a 64-slice multidetector scanner with prospective electrocardiographic triggering were retrospectively reviewed. Pixels in the pericardium with a density range from −230 to −30 Hounsfield units were considered fat, giving the per-slice epicardial fat area (EFA). The EFV was estimated by the summation of EFAs multiplied by the slice thickness. We investigated the relation between total EFV and each EFA.ResultsEFAs measured at several anatomical landmarks—right pulmonary artery, origins of the left main coronary artery, right coronary artery, coronary sinus—all correlated with the EFV (r = 0.77–0.92). The EFA at the LMCA level was highly reproducible and showed an excellent correlation with the EFV (r = 0.92).ConclusionThe EFA is significantly correlated with the EFV. The EFA is a simple, quick method for representing the time-consuming EFV, which has been used as a predictive indicator of cardiovascular diseases.

A Comparison of the Effects of the GLP-1 Analogue Liraglutide and Insulin Glargine on Endothelial Function and Metabolic Parameters : A Randomized, Controlled Trial Sapporo Athero-Incretin Study 2 (SAIS2)

Objectives GLP-1 improves hyperglycemia, and it has been reported to have favorable effects on atherosclerosis. However, it has not been fully elucidated whether GLP-1 is able to improve endothelial function in patients with type 2 diabetes. Therefore, we investigated the efficacy of the GLP-1 analogue, liraglutide on endothelial function and glycemic metabolism compared with insulin glargine therapy. Materials and Methods In this multicenter, prospective randomized parallel-group comparison study, 31 diabetic outpatients (aged 60.3 ± 10.3 years with HbA1c levels of 8.6 ± 0.8%) with current metformin and/or sulfonylurea treatment were enrolled and randomly assigned to receive liraglutide or glargine therapy once daily for 14 weeks. Flow mediated dilation (FMD), a comprehensive panel of hemodynamic parameters (Task Force Monitor), and serum metabolic markers were assessed before and after the treatment period. Results A greater reduction (worsening) in %FMD was observed in the glargine group, although this change was not statistically different from the liraglutide group (liraglutide; 5.7 to 5.4%, glargine 6.7 to 5.7%). The augmentation index, C-peptide index, derivatives of reactive oxygen metabolites and BMI were significantly improved in the liraglutide group. Central systolic blood pressure and NT-proBNP also tended to be improved in the liraglutide-treated group, while improvements in HbA1c levels were similar between groups. Cardiac index, blood pressure and most other metabolic parameters were not different. Conclusions Regardless of glycemic improvement, early liraglutide therapy did not affect endothelial function but may provide favorable effects on beta-cell function and cardioprotection in type 2 diabetics without advanced atherosclerosis. Trial Registration UMIN Clinical Trials Registry System as trial ID UMIN000005331.

Increased plasma concentrations of N-terminal pro-brain natriuretic peptide reflect the presence of mildly reduced left ventricular diastolic function in hypertension.

BackgroundThe potential use of assays of N-terminal pro-brain natriuretic peptide for detection of diastolic abnormalities associated with alterations in blood pressure has not been elucidated. This study was designed to determine whether increased plasma concentrations of N-terminal pro-brain natriuretic peptide sensitively reflect abnormal diastolic function associated with hypertension. MethodsConcentrations of N-terminal pro-brain natriuretic peptide in plasma were assayed in 40 previously untreated hypertensive patients without overt congestive heart failure and in 20 age and sex-matched controls. Hypertensive patients were studied with the use of pulsed Doppler and color M-mode Doppler echocardiography for the evaluation of left ventricular diastolic function. ResultsConcentrations of N-terminal pro-brain natriuretic peptide were elevated in hypertensive patients [75.1±75.2 (SD) pg/ml compared with 37.9±38.5 in controls, P<0.05]. In hypertensive patients, concentrations of N-terminal pro-brain natriuretic peptide were negatively correlated with the ratio of color M-mode flow propagation velocity to transmitral E velocity consistent with the view that increased concentrations of N-terminal pro-brain natriuretic peptide are indicative of alterations in diastolic function. Hypertensive patients with N-terminal pro-brain natriuretic peptide values above the mean value in the control group exhibited significantly increased brachial intimal–medial thickness and reduced wall stress, consistent with the view that increased N-terminal pro-brain natriuretic peptide was associated with favorable peripheral arterial remodeling. ConclusionsElevated concentrations of N-terminal pro-brain natriuretic peptide in plasma reflect the presence of left ventricular diastolic abnormalities and peripheral arterial remodeling in asymptomatic patients with hypertension.