Takahiro Okumura

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BACKGROUND The inhibition of dipeptidyl peptidase-4 (DPP4) protects the heart from acute myocardial ischemia. However, the role of DPP4 in chronic heart failure independent of coronary artery disease remains unclear. METHODS AND RESULTS We first localized the membrane-bound form of DPP4 to the capillary endothelia of rat and human heart tissue. Diabetes(More)
Immunohistochemical studies were performed to analyze the expressional changes in hippocampal synaptic vesicle protein 2A (SV2A) following pentylenetetrazole (PTZ) kindling. Repeated treatments of mice with sub-convulsive PTZ (40 mg/kg, i.p.) for 15 days progressively enhanced seizure susceptibility and induced clonic convulsions in most animals examined.(More)
OBJECTIVE Heart and aorta possess biologic clocks, but their involvement in genetic hypertension has been unknown. Plasminogen activator inhibitor-1 (PAI-1) expression is directly regulated by clock genes, while angiotensin II modulates both PAI-1 and clock gene expression. We therefore examined circadian expression of PAI-1 and clock genes, and effects of(More)
OBJECTIVES We evaluated the geographic distribution of thin-cap fibroatheromas (TCFAs) in the coronary arteries using optical coherence tomography (OCT), a high-resolution imaging modality. BACKGROUND Plaque rupture is the most frequent cause of acute myocardial infarction (AMI). It has been recognized that TCFA is the primary plaque type at the site of(More)
Activation of the Na+/H+ exchanger (NHE) is known to be related to elevated blood pressure in hyperinsulinemia. We previously demonstrated that a fructose-enriched diet induced hyperinsulinemia and hypertriglyceridemia, elevated NHE activity, increased intracellular calcium concentrations ([Ca2+]i), and increased blood pressure in borderline hypertensive(More)
BACKGROUND Serum indoxyl sulfate (IS) is a uremic toxin that accelerates the progression of chronic kidney disease (CKD). The aim of this study was to determine whether serum IS is associated with hemodynamic parameters or cardiac events in patients with nonischemic dilated cardiomyopathy (DCM). METHODS AND RESULTS The 76 patients with DCM had their serum(More)
BACKGROUND Epidemiologic investigations suggest that fish oil, which contains eicosapentaenoic acid (EPA), has favorable cardiovascular effects. Fish oil improves endothelial function in subjects with hypercholesterolemia or diabetes. However, controversy persists regarding relationships between primary hypertriglyceridemia and endothelial dysfunction.(More)
Bezafibrate, one of fibric acid derivatives, is widely used to treat hypertriglyceridemia and diabetic dyslipidemia. Fibric acid derivatives are known to induce rhabdomyolysis as a side effect, especially when given to patients with renal dysfunction. Mizoribine, an imidazole nucleoside, is used as an immunosuppressive agent. Here, we present a case of a(More)
BACKGROUND Cardiorespiratory fitness (CRF) can predict future cardiovascular disease. Rupture of vulnerable plaque which often has a large lipid core with a thin fibrous cap causes acute coronary syndrome including sudden cardiac death. We tested our hypothesis that preserved CRF is associated with low lipid composition and thick fibrous cap thickness of(More)