Biomedical subjects

Akane Kizu

Publications and source records attributed to Akane Kizu.

6 recordsLinked to original sources

PubMed2006

Receptor for advanced glycation end products is involved in impaired angiogenic response in diabetes.

Angiogenic response is impaired in diabetes. Here, we examined the involvement of receptor for advanced glycation end products (RAGE) in diabetes-related impairment of angiogenesis in vivo. Angiogenesis was determined in reconstituted basement membrane protein (matrigel) plugs containing vascular endothelial growth factor (VEGF) implanted into nondiabetic or insulin-deficient diabetic wild-type or RAGE(-/-) mice. The total, endothelial, and smooth muscle (or pericytes) cells in the matrigel were significantly decreased in diabetes, with the regulation dependent on RAGE. In the matrigel, proangiogenic VEGF expression was decreased, while antiangiogenic thrombospondin-1 was upregulated in diabetic mice, regardless of the presence of RAGE. In wild-type mice, proliferating cell nuclear antigen (PCNA)-positive cells in the matrigel were significantly less in diabetic than in nondiabetic mice, while the numbers of transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells were significantly higher. This alteration in PCNA- and TUNEL-positive cells in diabetes was not observed in RAGE(-/-) mice. Similarly, the percentage of nuclear factor kappaB-activated cells is enhanced in diabetes, with the regulation dependent on the presence of RAGE. Importantly, adenovirus-mediated overexpression of endogenous secretory RAGE, a decoy receptor for RAGE, restores diabetes-associated impairment of angiogenic response in vivo. Thus, RAGE appears to be involved in impairment of angiogenesis in diabetes, and blockade of RAGE might be a potential therapeutic target.

Adenoviridae↗

PubMed2004

Statins inhibit in vitro calcification of human vascular smooth muscle cells induced by inflammatory mediators.

Although lipid-lowering therapy with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) decreases the progression of coronary artery and aortic valve calcification, the mechanism of action of these drugs to inhibit the calcification process remains unclear. In this study, we investigated the effect of statins such as cerivastatin and atorvastatin on vascular calcification by utilizing an in vitro model of inflammatory vascular calcification. Cerivastatin and atorvastatin dose-dependently inhibited in vitro calcification of human vascular smooth muscle cells (HVSMCs) induced by the following inflammatory mediators (IM): interferon-gamma, 1alpha,25-dihydroxyvitamin D3, tumor necrosis factor-alpha, and oncostatin M. These statins also depressed expression of alkaline phosphatase (ALP) in HVSMCs induced by these factors. Mevalonate and geranylgeranylpyrophosphate reversed the inhibitory effect of cerivastatin on ALP expression in HVSMCs, while farnesylpyrophosphate showed no effect on the ALP activities inhibited by this drug, suggesting that inhibition of Rho and its downstream target, Rho kinase may mediate the inhibitory effect of cerivastatin. Cerivastatin prevented RhoA activation in HVSMCs induced by the IM. A specific inhibitor of Rho kinase (Y-27632) inhibited in vitro calcification and induction of ALP in HVSMCs. These findings provide a possible mechanism of statins to prevent the progression of calcification in inflammatory vascular diseases such as atherosclerosis and cardiac valvular calcification.

Alkaline Phosphatase↗

PubMed2004

Matrix Gla protein is associated with coronary artery calcification as assessed by electron-beam computed tomography.

Matrix Gla protein (MGP) is an extracellular matrix protein with wide tissue distribution. It has been demonstrated that the expression of MGP is detected not only in the normal blood vessels but also calcified atherosclerotic plaques, and that MGP deficient mice develop extensive arterial calcification. MGP is thought to be a regulator of vascular calcification. A recent clinical study demonstrates the association between polymorphisms of the MGP gene and increased risk of myocardial infarction. However, there are no reports of the relationship between serum MGP levels and coronary artery calcification (CAC). We evaluated the severity of CAC using electron-beam computed tomography (EBCT), and measured serum MGP levels by enzyme-linked immunosorbent assay in 115 subjects with suspected coronary artery disease. CAC scores were correlated with traditional risk factors, such as age, gender, hyper-tension, diabetes, hyperlipidemia and smoking. The serum MGP levels were lower in patients with CAC than in those without CAC (p<0.001). As the severity of CAC increased, there was a significant decrease in serum MGP levels. Serum MGP levels (U/L) were 116.7 +/- 20.3, 104.9 +/- 19.2, 95.2 +/- 15.2 and 82.2 +/- 19.7, (medians 115.5, 105.0, 94.8, and 81.9) for the subjects with normal (CAC score=0), mild (CAC score=1 to 99), moderate (CAC score=100 to 400), and severe (CAC score >400) coronary calcification, respectively. We found that serum MGP levels are inversely correlated with the severity of CAC. These data suggest a possible role for MGP in the development of vascular calcification.

Aged↗

PubMed2004

[Mechanism of vascular calcification].

Vascular calcification in dialysis patients is associated with morbidity and mortality risks. Recent evidence suggests that vascular calcification is an active process resembling osteogenesis and chondrogenesis process. In this process, hyperphosphatemia is one of the important regulators. Inorganic phosphates directly regulate vascular calcification in vitro through a sodium-dependent phosphate cotransporter and promote expression of the osteoblastic differentiation markers.

Animals↗

PubMed2003

Arterial wall stiffness is associated with peripheral circulation in patients with type 2 diabetes.

The prevalence of peripheral vascular disease (PVD) in diabetic patients is manyfold higher than that of age- and sex-matched nondiabetic subjects. This study was designed to evaluate the relationship between quantitatively determined peripheral circulation in the lower extremities and arterial wall thickness or stiffness in 68 patients with type 2 diabetes. Peripheral circulation during treadmill-exercise was monitored by transcutaneous oxygen tension (TcPO2) and was expressed as percentage of post-exercise TcPO2 adjusted by that of pre-exercise (TcPO2 index). Arterial wall thickness (intima-media thickness; IMT) and stiffness (stiffness beta) were measured by ultrasonography. TcPO2 index was negatively (r=-0.350, P=0.0007) correlated with stiffness beta, not with IMT, of the femoral artery. In patients without insulin therapy (n=52), both fasting plasma insulin concentration (r=-0.323, P=0.0023) and HOMA IR, an insulin resistance index, (r=-0.281, P=0.0084) were negatively correlated with TcPO2 index. Multiple regression analyses showed that association of stiffness beta of the femoral artery or HOMA IR with the TcPO2 index was independent of other factors including age, smoking index, ankle brachial pressure index and IMT of femoral artery. Thus, arterial wall stiffness of femoral artery appears to be a major determinant of peripheral circulation in patients with type 2 diabetes.

Age Factors↗

PubMed2002

[Not Available].

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Journal Article↗