Hyperglycemia Induces Cellular Hypoxia through Production of Mitochondrial ROS Followed by Suppression of Aquaporin-1.

We previously proposed that hyperglycemia-induced mitochondrial reactive oxygen species (mtROS) generation is a key event in the development of diabetic complications. Interestingly, some common aspects exist between hyperglycemia and hypoxia-induced phenomena. Thus, hyperglycemia may induce cellular hypoxia, and this phenomenon may also be involved in the pathogenesis of diabetic complications.

Dialysate vascular endothelial growth factor is an independent determinant of serum albumin levels and predicts future withdrawal from peritoneal dialysis in uremic patients.

Peritoneal protein loss due to high peritoneal permeability may contribute to hypoalbuminemia and early withdrawal from peritoneal dialysis (PD) therapy in end stage renal disease (ESRD) patients. We have found that pigment epithelium-derived factor (PEDF) has anti-vasopermeability properties both in cell culture and animal models by counteracting the biological actions of vascular endothelial growth factor (VEGF). However, it remains unknown which clinical variables, including dialysate VEGF and PEDF, are associated with decreased serum albumin levels and could predict early withdrawal from the PD in ESRD patients.

Plasma renin activity and aldosterone concentration are not altered by the novel calcium channel antagonist, azelnidipine, in hypertensive patients.

Objective: In hypertensive patients, primary aldosteronism (PA) is the most prevalent type of secondary hypertension, and screening for PA has become very important. Calcium channel blockers (CCB) are widely used to treat hypertension, but most CCBs stimulate plasma renin activity (PRA) and increase plasma aldosterone concentration (PAC), both of which are used in the screening for PA. The aim of this study was to determine whether the newly introduced CCB, azelnidipine, affects PRA and PAC.

Endothelial MnSOD overexpression prevents retinal VEGF expression in diabetic mice.

We previously proposed that hyperglycemia-induced mitochondrial ROS overproduction is a key event in the development of diabetic complications. In this study, we established a novel transgenic mouse (eMnSOD-Tg), which specifically expressed MnSOD in endothelial cells, by employing a Tie2 promoter/enhancer, and investigated the impact of mitochondrial ROS production on diabetic retinopathy in vivo. Using immunohistochemistry, overexpression of MnSOD in endothelial cells was confirmed in eMnSOD-Tg mice.

Impact of mitochondrial ROS production in the pathogenesis of insulin resistance.

Tumor necrosis factor-alpha (TNF-alpha) inhibits insulin action, in part, by activating c-jun NH(2)-terminal kinases (JNK). However, the precise mechanisms by which TNF-alpha activates JNK are unknown. Recently, we confirmed that hyperglycemia increased mitochondrial reactive oxygen species (ROS) production, and which can associate with the pathogenesis of diabetic vascular complications.

Statins activate peroxisome proliferator-activated receptor gamma through extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase-dependent cyclooxygenase-2 expression in macrophages.

Both statins and peroxisome proliferator-activated receptor (PPAR)gamma ligands have been reported to protect against the progression of atherosclerosis. In the present study, we investigated the effects of statins on PPARgamma activation in macrophages. Statins increased PPARgamma activity, which was inhibited by mevalonate, farnesylpyrophosphate, or geranylgeranylpyrophosphate.

Impact of mitochondrial ROS production on diabetic vascular complications.

Vascular complications are the leading cause of morbidity and mortality in patients with diabetes. Four main molecular mechanisms have been implicated in glucose-mediated vascular disease. There are: glucose-induced activation of protein kinase C (PKC) isoforms; increased formation of glucose-derived advanced glycation end-products (AGE); increased glucose flux through the aldose reductase pathway; and increased production of reactive oxygen species (ROS).

Relative effects of land use and near-stream chemistry on phosphorus in an urban stream.

Elevated levels of P in urban streams can pose significant water quality problems. Sources of P in urban streams, however, are difficult to identify. It is important to recognize both natural and anthropogenic sources of P.

Troglitazone inhibits oxidized low-density lipoprotein-induced macrophage proliferation: impact of the suppression of nuclear translocation of ERK1/2.

Thiazolidinediones (TZDs), which were known as novel insulin-sensitizing antidiabetic agents, have been reported to inhibit the acceleration of atherosclerotic lesions. Macrophages play important roles in the development of atherosclerosis. We previously reported that oxidized low-density lipoprotein (Ox-LDL) induces macrophage proliferation through ERK1/2-dependent GM-CSF production.

Impact of mitochondrial reactive oxygen species and apoptosis signal-regulating kinase 1 on insulin signaling.

Tumor necrosis factor (TNF)-alpha inhibits insulin action; however, the precise mechanisms are unknown. It was reported that TNF-alpha could increase mitochondrial reactive oxygen species (ROS) production, and apoptosis signal-regulating kinase 1 (ASK1) was reported to be required for TNF-alpha-induced apoptosis. Here, we examined roles of mitochondrial ROS and ASK1 in TNF-alpha-induced impaired insulin signaling in cultured human hepatoma (Huh7) cells.

Activation of AMP-activated protein kinase reduces hyperglycemia-induced mitochondrial reactive oxygen species production and promotes mitochondrial biogenesis in human umbilical vein endothelial cells.

We previously proposed that the production of hyperglycemia-induced mitochondrial reactive oxygen species (mtROS) is a key event in the development of diabetes complications. The association between the pathogenesis of diabetes and its complications and mitochondrial biogenesis has been recently reported. Because metformin has been reported to exert a possible additional benefit in preventing diabetes complications, we investigated the effect of metformin and 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) on mtROS production and mitochondrial biogenesis in cultured human umbilical vein endothelial cells.

Statins suppress oxidized low density lipoprotein-induced macrophage proliferation by inactivation of the small G protein-p38 MAPK pathway.

Inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase (statins) ameliorate atherosclerotic diseases. Macrophages play an important role in the development and subsequent stability of atherosclerotic plaques. We reported previously that oxidized low density lipoprotein (Ox-LDL) induced macrophage proliferation through the secretion of granulocyte/macrophage colony-stimulating factor (GM-CSF) and the consequent activation of p38 MAPK.

Extracellular signal-regulated kinase and p38 mitogen-activated protein kinase mediate macrophage proliferation induced by oxidized low-density lipoprotein.

We previously reported that oxidized low-density lipoprotein (Ox-LDL)-induced expression of granulocyte/macrophage colony-stimulating factor (GM-CSF) via PKC, leading to activation of phosphatidylinositol-3 kinase (PI-3K), was important for macrophage proliferation [J Biol Chem 275 (2000) 5810]. The aim of the present study was to elucidate the role of extracellular-signal regulated kinase 1/2 (ERK1/2) and of p38 MAPK in Ox-LDL-induced macrophage proliferation. Ox-LDL-induced proliferation of mouse peritoneal macrophages assessed by [3H]thymidine incorporation and cell counting assays was significantly inhibited by MEK1/2 inhibitors, PD98059 or U0126, and p38 MAPK inhibitors, SB203580 or SB202190, respectively.

15d-PGJ2 inhibits oxidized LDL-induced macrophage proliferation by inhibition of GM-CSF production via inactivation of NF-kappaB.

Macrophage-derived foam cells play an important role in atherosclerotic lesions. Oxidized low-density lipoprotein (Ox-LDL) induces macrophage proliferation via production of GM-CSF in vitro. This study investigated the effects of 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), a natural ligand for peroxisome proliferator-activated receptor gamma, on macrophage proliferation.

Reactive oxygen species from mitochondria induce cyclooxygenase-2 gene expression in human mesangial cells: potential role in diabetic nephropathy.

Hyperglycemia increases the production of reactive oxygen species (ROS) from the mitochondrial electron transport chain in bovine endothelial cells. Because several studies have postulated a role for prostaglandins (PGs) in the glomerular hyperfiltration seen in early diabetes, we evaluated the effect of mitochondrial ROS on expression of the inducible isoform of cyclooxygenase (COX-2) in cultured human mesangial cells (HMCs). We first confirmed that incubation of HMC with 30 mmol/l glucose significantly increased COX-2 mRNA but not COX-1 mRNA, compared with 5.

Evaluation of urinary 8-hydroxydeoxy-guanosine as a novel biomarker of macrovascular complications in type 2 diabetes.

Objective: To evaluate urinary 8-hydroxydeoxyguanosine (8-OHdG) as a marker for the progression of diabetic macroangiopathic complications.

Research Design And Methods: The content of urinary 8-OHdG, common carotid intima-media thickness (IMT), the coronary heart disease (CHD) risk score, the severity of diabetic retinopathy, and urinary albumin excretion were examined in 96 patients with type 2 diabetes, including 32 patients who had been nominated for the Kumamoto Study [Shichiri M, et al. Diabetes Care 23 (Suppl 2):B21-B29, 2000].

Sudden onset of diabetes with ketoacidosis in a patient treated with FK506/tacrolimus.

We report a 43-year-old man who presented diabetic ketoacidosis 1 year after receiving kidney transplantation. He was a recipient of renal transplantation treated with metyl-prednisolone and tacrolimus regimen. The serum level of tacrolimus was 12.