Takahito Itoh

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RATIONALE The diabetic heart is resistant to ischemic preconditioning because of diabetes-associated impairment of phosphatidylinositol 3-kinase (PI3K)-Akt signaling. The mechanism by which PI3K-Akt signaling is impaired by diabetes remains unclear. OBJECTIVE Here, we examined the hypothesis that phosphorylation of Jak2 upstream of PI3K is impaired in(More)
In spite of the current optimal therapy, the mortality of patients with ischemic heart disease (IHD) remains high, particularly in cases with diabetes mellitus (DM) as a co-morbidity. Myocardial infarct size is a major determinant of prognosis in IHD patients, and development of a novel strategy to limit infarction is of great clinical importance. Ischemic(More)
Ischemic preconditioning (PC) suppresses chemical coupling of cardiomyocytes via gap junctions (GJs) during ischemia, which is an adjunct mechanism of protection. The aim of this study was to characterize roles of protein kinases in PC-induced GJ modulation. In isolated rat hearts, ventricular tissues were sampled before and after ischemia with or without(More)
The objective of this study was to examine the hypothesis that hypertensive hypertrophy is vulnerable to infarction and defective in cytoprotective mechanisms by modification of intracellular signaling and mitochondrial proteins. Myocardial infarction was induced by 20-minute coronary occlusion/reperfusion in spontaneously hypertensive stroke-prone rats(More)
BACKGROUND Diabetes mellitus (DM) is associated with an increased risk of ischemic heart disease and of adverse outcomes following myocardial infarction (MI). Here we assessed the role of endoplasmic reticulum (ER) stress in ventricular dysfunction and outcomes after MI in type 2 DM (T2DM). METHODOLOGY AND PRINCIPAL FINDINGS In hearts of OLETF, a rat(More)
Sarcolemmal connexin-43 (Cx43) and mitochondrial Cx43 play distinct roles: formation of gap junctions and production of reactive oxygen species (ROS) for redox signaling. In this study, we examined the hypothesis that Cx43 contributes to activation of a major cytoprotective signal pathway, phosphoinositide 3-kinase (PI3K)-Akt-glycogen synthase kinase-3β(More)
Our recent studies indicated that up-regulation of calcineurin activity and unfolded protein responses (UPRs) disrupt cytoprotective Akt- and ERK-signaling in OLETF, a model of obese type 2 diabetes (T2DM). To determine whether the mechanisms can be generalized, we used Goto-Kakizaki rats (GK), a model of non-obese T2DM, in this study. Infarct sizes after(More)
The aim of this study was to determine the roles of glycogen synthase kinase-3β (GSK-3β) in cardioprotection by activation of the mitochondrial ATP-sensitive K(+) channel (mK(ATP) channel). In isolated rat hearts, an mK(ATP) activator, diazoxide, and a GSK-3β inhibitor, SB216763, similarly limited infarct size and the combination of these agents did not(More)
Here, we describe a case of nonvisualized type III endoleak masquerading as endotension that was diagnosed by opening the aneurysm sac during surgery and successfully treated surgically. A 79-year-old man underwent endovascular aneurysm repair (EVAR) 4 years previously for an aneurysm that had enlarged gradually without endoleak. An open surgical operation(More)
Type 2 diabetes mellitus (T2DM) is often complicated with diastolic heart failure, which decompensates under increased afterload. Focusing on cardiac metabolomes, we examined mechanisms by which T2DM augments ventricular diastolic stiffness in response to pressure overloading. Pressure-volume relationships (PVRs) and myocardial metabolomes were determined(More)