Comparison of Direct and Indirect Antioxidant Effects of Linagliptin (BI 1356, ONDERO) with other Gliptins – Evidence for Anti-inflammatory Properties of Linagliptin

Vascular Dysfunction in Streptozotocin-Induced Experimental Diabetes Strictly Depends on Insulin Deficiency

<i>Objective:</i> In previous studies we and others have shown that streptozotocin (STZ)-induced diabetes in rats is associated with vascular oxidative stress and dysfunction. In the present study, we sought to determine whether vascular dysfunction and oxidative stress strictly depend on insulin deficiency. <i>Methods:</i> The effects of insulin (2.5 U/day s.c., 2 weeks) therapy on vascular disorders in STZ-induced (60 mg/kg i.v., 8 weeks) diabetes mellitus (type I) were studied in Wistar rats. The contribution of NADPH oxidase to overall oxidative stress was investigated by in vivo (30 mg/kg/day s.c., 4 days) and in vitro treatment with apocynin. <i>Results:&…

Nitroglycerin-induced endothelial dysfunction and tolerance involve adverse phosphorylation and S-glutathionylation of endothelial nitric oxide synthase — Beneficial effects of therapy with the AT1-receptor blocker telmisartan

Continuous administration of nitroglycerin (GTN) causes tolerance and endothelial dysfunction by inducing reactive oxygen species (ROS) production from various enzymatic sources, such as mitochondria, NADPH oxidase, and an uncoupled endothelial nitric oxide synthase (eNOS). In the present study, we tested the effects of type 1 angiotensin (AT(1))-receptor blockade with telmisartan on GTN-induced endothelial dysfunction in particular on eNOS phosphorylation and S-glutathionylation sites and the eNOS cofactor synthesizing enzyme GTP-cyclohydrolase I.Wistar rats were treated with telmisartan (2.7 or 8 mg/kg per day PO for 10 days) and with GTN (50 mg/kg per day SC for 3 days). Aortic eNOS phos…

Vascular Dysfunction in Nitroglycerininduced Nitrate Tolerance is Improved by Telmisartan Therapy — Suppression of the RAAS and PKC Pathway

Vascular Dysfunction in Experimental Diabetes Is Improved by Pentaerithrityl Tetranitrate but Not Isosorbide-5-Mononitrate Therapy

OBJECTIVE Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes. RESEARCH DESIGN AND METHODS After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and o…

Nitroglycerin-Induced Endothelial Dysfunction and Tolerance Involve Adverse Phosphorylation and S -Glutathionylation of Endothelial Nitric Oxide Synthase

Objective— Continuous administration of nitroglycerin (GTN) causes tolerance and endothelial dysfunction by inducing reactive oxygen species (ROS) production from various enzymatic sources, such as mitochondria, NADPH oxidase, and an uncoupled endothelial nitric oxide synthase (eNOS). In the present study, we tested the effects of type 1 angiotensin (AT 1 )-receptor blockade with telmisartan on GTN-induced endothelial dysfunction in particular on eNOS phosphorylation and S -glutathionylation sites and the eNOS cofactor synthesizing enzyme GTP–cyclohydrolase I. Methods and Results— Wistar rats were treated with telmisartan (2.7 or 8 mg/kg per day PO for 10 days) and with GTN (50 mg/kg per d…

Hyperglycemia and oxidative stress in cultured endothelial cells – a comparison of primary endothelial cells with an immortalized endothelial cell line

Diabetes mellitus is a major risk factor for the development of cardiovascular disease and oxidative stress plays an important role in this process. Therefore, we investigated the effects of hyperglycemia on the formation of reactive oxygen species (ROS) and nitric oxide/cGMP signaling in two different endothelial cell cultures. Human umbilical vein endothelial cells (HUVEC) and EA.hy 926 cells showed increased oxidative stress and impaired NO-cGMP signaling in response to hyperglycemia. The major difference between the two different cell types was the dramatic decrease in viability in HUVEC whereas EA.hy cells showed rather increased growth under hyperglycemic conditions. Starvation led to…

Regulation of Human ALDH-2 Activity by Electrophiles – Implications for Organic Nitrate Induced Tolerance, Oxidative Stress and Reactive Fatty Acid Metabolites in MI