maxacalcitol and Diabetes-Mellitus--Type-2

We aimed to assess the effect of long-term pioglitazone treatment on erythropoietin responsiveness and insulin resistance in type 2 diabetic patients on hemodialysis.. We conducted a prospective, open-label, parallel-group, controlled study of 63 type 2 diabetic hemodialysis patients who were randomly assigned to two groups: pioglitazone group (P-group; 15-30 mg/day pioglitazone plus conventional oral hypoglycemic agents) and control group (C-group; conventional oral hypoglycemic agents alone). We determined the efficacy of pioglitazone by monitoring anemia, glycemic control, insulin resistance, and levels of inflammatory cytokines and high-molecular-weight (HMW) adiponectin for 96 weeks.. Pioglitazone effectively reduced erythropoietin dose and maintained the target hemoglobin levels by improving insulin resistance up to the end of the study. In the P-group, hemoglobin A(1c), glycated albumin, and triglycerides significantly decreased compared with the C-group. There was a significant reduction in homeostasis model assessment for insulin resistance and the level of high-sensitivity C-reactive protein, and a significant increase in HMW adiponectin level in the P-group; these changes were significantly different compared with values for the C-group. No serious adverse effects such as hypoglycemia, liver impairment, or heart failure were observed in any of the patients.. Pioglitazone treatment resulted in better glycemic control, improved lipid levels, an increase in insulin sensitivity and adiponectin levels, and a decrease in inflammatory markers, thus improving the risk factors of cardiovascular disease. Erythropoietin responsiveness improved with a reduction in erythropoietin dose and may be associated with the improvement in insulin resistance due to long-term pioglitazone treatment.

Topics: Adiponectin; Adult; Aged; Anemia; Blood Pressure; C-Reactive Protein; Calcitriol; Diabetes Mellitus, Type 2; Erythropoietin; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin Resistance; Male; Middle Aged; Pioglitazone; Prospective Studies; Recombinant Proteins; Renal Dialysis; Thiazolidinediones

Active vitamin D is a major therapeutic agent for bone disease. Although some studies have reported that vitamin D ameliorates bone disease related to diabetes, the mechanism remains unclear. Our study investigated the effect of the vitamin D receptor activator 22-oxacalcitriol (OCT) on bone disease in a rat model of diabetes. OCT was administered at a dose of 0.2μg/kg three times per week for 10weeks. We performed blood and urine analyses, single energy X-ray absorptiometry, micro-computed tomography, bone histomorphometry, and oxidative stress assessment in rats at 30weeks of age. OCT did not affect hemoglobin A1c or serum calcium levels. Bone mineral density (BMD), bone volume in the cortical and trabecular bones, and bone turnover were decreased in rats with diabetes. OCT treatment increased BMD and bone formation and tended to increase bone volume in the trabecular bone, but did not change bone volume in the cortical bone or bone resorption. The urinary oxidative stress marker 8-hydroxydeoxyguanosine (8-OHdG) excretion and the number of 8-OHdG-positive cells in bone were increased in rats with diabetes, and OCT treatment suppressed these increases. Our data suggest that OCT attenuated bone loss in a rat model of diabetes. This attenuation may be partially mediated by improved bone formation resulting from the antioxidative effect of OCT.

Topics: Absorptiometry, Photon; Animals; Bone Density; Bone Resorption; Calcitriol; Diabetes Mellitus, Type 2; Femur; Insulin; Male; Obesity; Oxidative Stress; Rats, Sprague-Dawley; Tibia; X-Ray Microtomography

Diabetic nephropathy is a major risk of end-stage kidney disease. Many complex factors relate to the progression of diabetic nephropathy. Using nonobese type 2 diabetes model rats, we confirmed that oxidative stress was a crucial factor. Because recent studies suggest that vitamin D could suppress oxidative stress, we explored whether the active vitamin D analog, maxacalcitol, could also attenuate oxidative stress and prevent the progression of diabetic nephropathy.. Diabetic rats aged 20 weeks were divided into 3 groups and treated with insulin, maxacalcitol, and vehicle. At age 30 weeks, blood and urine analyses, renal histology, immunohistochemistry, real-time polymerase chain reaction, and western blot were performed.. Although maxacalcitol reduced albuminuria and mesangial matrix expansion, no significant differences were observed in blood pressure and creatinine clearance among the 3 treatment groups. Systemic and intrarenal oxidative stress was reduced by maxacalcitol therapy. Expressions of nuclear factor-κB and nicotinamide adenine dinucleotide phosphate oxidase in the kidney also decreased in the insulin-treated and maxacalcitol-treated groups but increased in the vehicle-alone group. In addition, the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) decreased and Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1) increased in the vehicle-treated group; however, these expressions were restored in the maxacalcitol- and insulin-treated groups.. It is suggested that maxacalcitol attenuates the progression of diabetic nephropathy by suppression of oxidative stress and amelioration of the Nrf2-Keap1 pathway in nonobese type 2 diabetes without significant changes in blood pressure and glomerular filtration rate.

Topics: Albuminuria; Animals; Antioxidants; Calcitriol; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Insulin; Intracellular Signaling Peptides and Proteins; Kelch-Like ECH-Associated Protein 1; Kidney Glomerulus; Male; NADPH Oxidases; NF-E2-Related Factor 2; Oxidative Stress; Rats; Receptors, Calcitriol

Vascular disease is one of the critical complications of diabetes. A growing body of evidence suggests that oxidative stress plays a key role for vascular disease progression. Recent studies have demonstrated a strong link between vitamin D and cardiovascular disease.. We investigated the anti-oxidative effects of a vitamin D analog, 22-oxacalcitriol (maxacalcitol), on vascular lesions in type 2 diabetic rats. We used Spontaneously Diabetic Torii (SDT) rats, a model of non-obese type 2 diabetes. At 20 weeks of age, SDT rats were randomly divided into three groups: diabetes mellitus (DM, n = 10), DM + maxacalcitol (DM + D, n = 10), and DM + insulin (DM + I, n = 10). The rats were sacrificed at 30 weeks for the evaluation of blood and urine samples as well as histopathology and mRNA expression in the aorta.. Urinary 8-hydroxydeoxyguanosine (8-OHdG) excretion and the number of 8-OHdG-positive cells were significantly lower in the DM + I and DM + D groups than in the DM group. Real-time polymerase chain reaction analysis demonstrated that NADPH p22 phox and NADPH p47 phox mRNA levels were markedly decreased in the DM + I and DM + D groups compared with the DM group. Furthermore, the mRNA expression of MCP-1, ICAM-1 and VCAM-1 was significantly reduced in the DM + I and DM + D groups compared with the DM group.. Our results suggest that the vasoprotective effects of vitamin D are mediated by reducing oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Aorta; C-Reactive Protein; Calcitriol; Chemokine CCL2; Deoxyguanosine; Diabetes Mellitus, Type 2; Insulin; Intercellular Adhesion Molecule-1; Interleukin-1; NADPH Oxidases; Oxidative Stress; Rats; RNA, Messenger; Vascular Cell Adhesion Molecule-1; Vascular Diseases

Vitamin D deficiency is associated with endothelial dysfunction in type 2 diabetes patients, but the effectiveness of vitamin D supplementation remains controversial. We assessed whether 22-oxacalcitriol (OCT) could prevent endothelial dysfunction in type 2 diabetes mellitus (DM) rats.. DM rats with early-stage nephropathy were treated for 10 weeks with OCT (0.2 μg/kg) three times per week or by an implanted insulin pellet. Endothelial dysfunction was assessed by femoral flow-mediated dilation (FMD).. Insulin significantly improved FMD as blood glucose levels normalized. OCT also improved FMD without hypercalcemia or hyperphosphatemia and without affecting blood glucose or blood pressure. In femoral arteries, OCT significantly suppressed the elevated expression of p22(phox), a nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit, and improved the endothelial nitric oxide synthase (eNOS) dimer-to-monomer ratio. In cultured endothelial cells, OCT significantly inhibited high-glucose (HG)-induced reactive oxygen species (ROS) production. Simultaneously, OCT significantly suppressed HG-induced p22(phox) expression and improved eNOS uncoupling as was observed in the in vivo study.. In DM rats, OCT improved endothelial dysfunction, at least in part, by suppressing ROS generation through p22(phox) expression, which might contribute to improving eNOS uncoupling.

Topics: Animals; Antineoplastic Agents; Blotting, Western; Calcitriol; Cells, Cultured; Coronary Vessels; Diabetes Mellitus, Type 2; Endothelium, Vascular; Humans; Kidney Diseases; Male; NADPH Oxidases; Nitric Oxide Synthase Type III; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Vasodilation