Publications by authors named "Kumiko Taguchi"

Endothelial dysfunction exacerbates hypertension and other vascular complications in diabetes mellitus (DM). Circulating microparticles (MPs) and extracellular vesicles released in patients with DM have emerged as novel regulators of endothelial dysfunction. The obstruction of mineralocorticoid receptors (MRs) is a potential therapeutic approach to reduce cardiovascular complications.

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Maintaining endothelial cell (EC) and vascular smooth muscle cell (VSMC) integrity is an important component of human health and disease because both EC and VSMC regulate various functions, including vascular tone control, cellular adhesion, homeostasis and thrombosis regulation, proliferation, and vascular inflammation. Diverse stressors affect functions in both ECs and VSMCs and abnormalities of functions in these cells play a crucial role in cardiovascular disease initiation and progression. Toll-like receptors (TLRs) are important detectors of pathogen-associated molecular patterns derived from various microbes and viruses as well as damage-associated molecular patterns derived from damaged cells and perform innate immune responses.

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Vascular tone regulation is a key event in controlling blood flow in the body. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) help regulate the vascular tone. Abnormal vascular responsiveness to various stimuli, including constrictors and dilators, has been observed in pathophysiological states although EC and VSMC coordinate to maintain the exquisite balance between contraction and relaxation in vasculatures.

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Endothelial dysfunction-a hallmark of chronic kidney disease (CKD)-is one of the major risk factors for cardiovascular diseases (CVD). Imbalances in endothelium-derived relaxing factors (EDRFs) and contracting factors (EDCFs) specific to endothelial dysfunction in CKD are yet to be studied. Therefore, using adenine-treated rats-a CKD rat model-we investigated the responsiveness of superior mesenteric artery (SMA) endothelium to acetylcholine (ACh) stimulation under different experimental conditions.

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Ginkgo biloba extract (GBE) helps lower cardiovascular disease risk. Diabetes mellitus (DM)-induced endothelial dysfunction is a critical and initiating factor in the beginning of diabetic vascular complications. It was reported that GBE causes an endothelial-dependent relaxation.

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Endothelial dysfunction contributes to cardiometabolic disorders, including hypertension, obesity, and type 2 diabetes. Esaxerenone is a selective, nonsteroidal, high-affinity mineralocorticoid receptor blocker recently approved in Japan for the treatment of hypertension. Although imbalanced signaling between vasorelaxant and vasocontractile factors induced by endothelial stimulation is often observed in type 2 diabetic vessels, the effects of esaxerenone on endothelium-dependent responses in type 2 diabetes remain unclear.

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The protein-bound uremic toxin indoxyl sulfate has negative effects on a variety of physiological activities including vascular function. Uridine adenosine tetraphosphate (UpA), a new dinucleotide molecule affects vascular function including induction of vasocontraction, and aberrant responsiveness to UpA is evident in arteries from disorders such as hypertension and diabetes. The link between indoxyl sulfate and the UpA-mediated response is, however, unknown.

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Although methylglyoxal (MGO), a highly reactive dicarbonyl compound, influences the functioning of the vasculature, modulating its effects on vascular reactivity to various substances remains unclear, especially purinoceptor ligands. Therefore, we sought to investigate the direct effects of MGO on relaxation induced by adenosine 5'-triphosphate (ATP) and uridine 5'-triphosphate (UTP) in isolated rat carotid arteries. When carotid arteries were exposed to MGO (420 μM for 1 h), relaxation induced by acetylcholine or sodium nitroprusside was not affected by MGO.

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Although femoral artery dysfunctions, including aberrant vascular reactivity to vasoactive substances, are common in many chronic disorders, such as diabetes and hypertension, their inducible and/or progressive factors remain unclear. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, has been implicated in the pathogenesis of various chronic disorders. However, its direct correlation with extracellular nucleotides including uridine 5'-diphosphate (UDP) in the femoral artery function is currently unknown.

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Emerging evidences suggest that gut microbiota-derived substances play a pivotal role in the regulation of host homeostasis including vascular function. Actually, these substances and/or their metabolites can be presented in circulation and local tissue and their levels are often abnormal in the pathophysiological states. Therefore, to determine the role of them in physiological function is important in human health.

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Vascular smooth muscle cells (VSMCs) and endothelial cells (ECs) are major cell types that control vascular function, and hence dysfunction of these cells plays a key role in the development and progression of vasculopathies. Abnormal vascular responsiveness to vasoactive substances including vasoconstrictors and vasodilators has been observed in various arteries in diseases including diabetes, hypertension, chronic kidney diseases, and atherosclerosis. Several substances derived from ECs tightly control vascular function, such as endothelium-derived relaxing and contracting factors, and it is known that abnormal vascular signaling of these endothelium-derived substances is often observed in various diseases.

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Endothelial dysfunction contributes to the development of diabetic complications and the production of circulating microparticles (MPs). Our previous study showed that diabetic mice-derived MPs (DM MPs) had increased levels of extracellular regulated protein kinase 1/2 (ERK1/2) and impaired endothelial-dependent relaxation in aortas when compared with control mice-derived MPs. This study was designed to investigate whether PD98059, an ERK1/2 inhibitor, affects the function of aortas and DM MPs.

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We investigated the vascular response to nucleobase adenine using freshly isolated superior mesenteric arteries of spontaneously hypertensive rats (SHR) and its control, Wistar Kyoto (WKY) rats. Endothelium-dependent and endothelium-independent relaxations were assessed in isolated segments in an organ bath. The releases of the metabolites of thromboxane A and prostaglandin I were also detected.

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Introduction: Femoral arterial dysfunction including abnormal vascular responsiveness to endogenous ligands was often seen in arterial hypertension. Extracellular nucleotides including uridine 5'-diphosphate (UDP) and uridine 5'-triphosphate (UTP) play important roles for homeostasis in the vascular system including controlling the vascular tone. However, responsiveness to UDP and UTP in femoral arteries under arterial hypertension remains unclear.

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The microbiome-derived tryptophan metabolite, indoxyl sulfate, is considered a harmful vascular toxin. Here, we examined the effects of indoxyl sulfate on endothelin-1 (ET-1)-induced contraction in rat thoracic aortas. Indoxyl sulfate (10 M, 60 min) increased ET-1-induced contraction but did not affect isotonic high-K-induced contraction.

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The methylglyoxal elicits diverse adverse effects on the body. Uridine diphosphate, an extracellular nucleotide, plays an important role as a signaling molecule controlling vascular tone. This study aimed to evaluate the relationship between methylglyoxal and uridine diphosphate-induced carotid arterial contraction in rats.

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Extracellular nucleotides play an important role in the regulation of vascular function, and an abnormal vascular function is an important participant in the development and progression of diabetic vascular complications. The purpose of this study was to determine whether contractile responses induced by extracellular nucleotides and a dinucleotide, uridine adenosine tetraphosphate (UpA), in femoral arteries would be altered at the chronic stage of type 2 diabetes. We determined the changes in contractile reactivity induced by ATP, uridine triphosphate (UTP), uridine diphosphate (UDP), and UpA in the femoral arteries of Otsuka Long-Evans Tokushima Fatty (OLETF) rats (aged male type 2 diabetic rats) and, Long-Evans Tokushima Otsuka (LETO) rats (controls for OLETF rats).

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Aims: Diabetes impairs insulin-induced endothelium-dependent relaxation by reducing nitric oxide (NO) production. GLP-1, an incretin hormone, has been shown to prevent the development of endothelial dysfunction. In this study, we hypothesized that GLP-1 would improve the impaired insulin-induced relaxation response in diabetic mice.

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Uridine 5'-triphosphate (UTP) has an important role as an extracellular signaling molecule that regulates inflammation, angiogenesis, and vascular tone. While chronic hypertension has been shown to promote alterations in arterial vascular tone regulation, carotid artery responses to UTP under hypertensive conditions have remained unclear. The present study investigated carotid artery responses to UTP in spontaneously hypertensive rats (SHR) and control Wistar Kyoto rats (WKY).

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Diabetic vascular complications are associated with endothelial dysfunction. Various plant-derived polyphenols benefit cardiovascular function by protecting endothelial nitric oxide (NO) production through as yet unclear mechanisms. This study compared the effects of two structurally similar polyphenols, Morin (MO) and Quercetin (QU), on endothelial function in isolated aorta from control and streptozotocin (STZ)-induced diabetic mice.

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Although vascular dysfunction is a key event in the development of diabetic complications, and abnormal toll-like receptor 4 (TLR4) may contribute to the pathophysiology of vascular diseases, the direct relationships between TLR4 and vascular function in diabetic arteries are still poorly understood. Thus, to investigate whether pharmacological blockade of TLR4 affects vascular function in the superior mesenteric artery (SMA) of streptozotocin (STZ)-induced diabetic rats, the SMA was isolated from male Wistar rat injected once with STZ (65 mg/kg, 27-34 weeks) which was treated with TAK-242 (10 M), a TLR4 inhibitor, for approximately 1 d using organ culture techniques. After incubation, functional and biochemical studies were performed.

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Gut microbiota have been emerging as important contributors to the regulation of host homeostasis. Accordingly, several substances converted by gut microbiota can have beneficial or adverse effects on human health. Among them, S-equol, which is produced from the isoflavone daidzein in the human and animal gut by certain microbiota, exerts estrogenic and antioxidant activities.

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Although substantial evidence suggests that an increase in the level of trimethylamine-N-oxide (TMAO) is associated with the risk of cardiovascular diseases, including atherosclerosis, chronic kidney diseases, and hypertension, the direct effect of TMAO on vascular endothelial function remains unclear. Therefore, we investigated the acute effects of TMAO on endothelium-dependent relaxation induced by acetylcholine (ACh) in the superior mesenteric arteries and femoral arteries of rat. In endothelium-intact preparations, it was observed that TMAO (300 µmol/L for 60 min) did not affect ACh-induced relaxation in either of the two arteries.

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We investigated the direct effects of prolonged exposure to advanced glycation end-products (AGEs) on noradrenaline-induced contraction of rat carotid artery smooth muscle. Noradrenaline-induced contraction of endothelium-denuded carotid artery rings was suppressed by AGE-bovine serum albumin (AGE-BSA) pretreatment (0.01 and 0.

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