4-hydroxy-2-nonenal and Diabetic-Angiopathies

To investigate the effects of propionyl l-carnitine (PLC) on clinical and functional parameters, and markers of the overall oxidation state in patients with peripheral arterial disease (PAD) associated with non-insulin-dependent diabetes mellitus (NIDDM).. Randomised, double-blind, clinical trial, conducted in the Unit of Medical Angiology of the University of Catania.. Seventy-four patients with NIDDM-associated PAD were treated with PLC (2 g/day) or placebo for 12 months.. Ankle/brachial index (ABI) and the distance of pain-free walking were evaluated at baseline, 6 and 12 months. Malondialdehyde, 4-hydroxynonenal, oxidation time of low-density lipoproteins, and nitrite/nitrate ratio were measured as indices of the overall oxidation profiles at baseline and 12 months.. In the PLC group, ABI progressively increased (0.78, 0.83, and 0.88 at 0, 6 and 12 months, respectively). The distance of pain-free walking also improved (366.4, 441.9 and 519.8 m, respectively). In the placebo group, these parameters were relatively unchanged. Significant improvements in all parameters of the oxidative profile were seen in the PLC-treated group, with only minor variations observed in the placebo group.. These results suggest that adjunct therapy with PLC may be warranted in type 2 diabetes-associated PAD.

Topics: Aged; Aldehydes; Ankle; Blood Glucose; Blood Pressure; Brachial Artery; Carnitine; Cholesterol, LDL; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Double-Blind Method; Glycated Hemoglobin; Humans; Malondialdehyde; Middle Aged; Oxidation-Reduction; Pain Measurement; Placebos

Fibroblast growth factor 21 (FGF21) is an important regulator in glucose and lipid metabolism, and has been considered as a potential therapy for diabetes. The effect of FGF21 on the development and progression of diabetes-induced pathogenic changes in the aorta has not currently been addressed. To characterize these effects, type 1 diabetes was induced in both FGF21 knockout (FGF21KO) and C57BL/6 J wild type (WT) mice via multiple-dose streptozotocin injection. FGF21KO diabetic mice showed both earlier and more severe aortic remodeling indicated by aortic thickening, collagen accumulation and fibrotic mediator connective tissue growth factor expression. This was accompanied by significant aortic cell apoptosis than in WT diabetic mice. Further investigation found that FGF21 deletion exacerbated aortic inflammation and oxidative stress reflected by elevated expression of tumor necrosis factor α and transforming growth factor β, and the accumulation of 3-nitrotyrocine and 4-Hydroxynonenal. FGF21 administration can reverse the pathologic changes in FGF21KO diabetic mice. These findings demonstrate that FGF21 deletion aggravates aortic remodeling and cell death probably via exacerbation of aortic inflammation and oxidative stress. This marks FGF21 as a potential therapy for the treatment of aortic damage due to diabetes.

Topics: Aldehydes; Animals; Aorta; Aortic Diseases; Apoptosis; Collagen; Connective Tissue Growth Factor; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Angiopathies; Fibroblast Growth Factors; Fibrosis; Gene Deletion; Genetic Predisposition to Disease; Male; Mice, Inbred C57BL; Mice, Knockout; Nitric Oxide Synthase Type III; Oxidative Stress; Phenotype; Signal Transduction; Time Factors; Transforming Growth Factor beta; Tumor Necrosis Factor-alpha; Tyrosine; Vascular Remodeling

To investigate the effect of the GPx1-mimetic ebselen on diabetes-associated atherosclerosis and renal injury in a model of increased oxidative stress.. The study was performed using diabetic apolipoprotein E/GPx1 (ApoE(-/-)GPx1(-/-))-double knockout (dKO) mice, a model combining hyperlipidemia and hyperglycemia with increased oxidative stress. Mice were randomized into two groups, one injected with streptozotocin, the other with vehicle, at 8 weeks of age. Groups were further randomized to receive either ebselen or no treatment for 20 weeks.. Ebselen reduced diabetes-associated atherosclerosis in most aortic regions, with the exception of the aortic sinus, and protected dKO mice from renal structural and functional injury. The protective effects of ebselen were associated with a reduction in oxidative stress (hydroperoxides in plasma, 8-isoprostane in urine, nitrotyrosine in the kidney, and 4-hydroxynonenal in the aorta) as well as a reduction in VEGF, CTGF, VCAM-1, MCP-1, and Nox2 after 10 weeks of diabetes in the dKO aorta. Ebselen also significantly reduced the expression of proteins implicated in fibrosis and inflammation in the kidney as well as reducing related key intracellular signaling pathways.. Ebselen has an antiatherosclerotic and renoprotective effect in a model of accelerated diabetic complications in the setting of enhanced oxidative stress. Our data suggest that ebselen effectively repletes the lack of GPx1, and indicate that ebselen may be an effective therapeutic for the treatment of diabetes-related atherosclerosis and nephropathy. Furthermore, this study highlights the feasibility of addressing two diabetic complications with one treatment regimen through the unifying approach of targeted antioxidant therapy.

Topics: Aldehydes; Animals; Antioxidants; Apolipoproteins E; Atherosclerosis; Azoles; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Diabetic Nephropathies; Glutathione Peroxidase; Glutathione Peroxidase GPX1; Isoindoles; Kidney; Male; Mice; Mice, Knockout; Organoselenium Compounds; Reactive Oxygen Species; Tyrosine; Vascular Cell Adhesion Molecule-1

Carbonyl stress is one of the important mechanisms of tissue damage in vascular complications of diabetes. In the present study, we observed that the plasminogen activator inhibitor-1 (PAI-1) levels in serum and its gene expression in adipose tissue were up-regulated in aged OLETF rats, model animals of obese type 2 diabetes. To study the mechanism of PAI-1 up-regulation, we examined the effect of advanced glycation end products (AGEs) and the product of lipid peroxidation (4-hydroxy-2-nonenal (HNE)), both of which are endogenously generated under carbonyl stress. Stimulation of primary white adipocytes by either AGE or HNE resulted in the elevation of PAI-1 in culture medium and at mRNA levels. The up-regulation of PAI-1 was also observed by incubating the cells in high glucose medium (30 mm, 48 h). The stimulatory effects by AGE or high glucose were inhibited by antioxidant, pyrrolidine dithiocarbamate, and reactive oxygen scavenger, probucol, suggesting a pivotal role of oxidative stress in white adipocytes. We also found that the effect by HNE was inhibited by antioxidant, N-acetylcysteine and that a specific inhibitor of glutathione biosynthesis, l-buthionine-S,R-sulfoximine, augmented the effect of subthreshold effect of HNE. Bioimaging of reactive oxygen species (ROS) by a fluorescent indicator, 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate, revealed ROS production in white adipocytes treated with AGE or HNE. These results suggest that cellular carbonyl stress induced by AGEs or HNE may stimulate PAI-1 synthesis in and release from adipose tissues through ROS formation.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcysteine; Adipocytes; Aldehydes; Animals; Antioxidants; Buthionine Sulfoximine; Cells, Cultured; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Free Radical Scavengers; Glycation End Products, Advanced; Lipid Peroxidation; Male; NF-kappa B; Oxidative Stress; Plasminogen Activator Inhibitor 1; Rats; Rats, Inbred OLETF; Reactive Oxygen Species; RNA, Messenger; Up-Regulation

Syrian hamsters of the APA strain (APA hamsters) have recently been shown to have atheromatous lesions in the aortic arches under diabetic condition induced by a single injection of streptozotocin (SZ). In that model, fatty streaks, which are the initial lesions of atherogenesis, develop by 6 weeks after the injection (WAI). In this study, we evaluated plasma lipid concentrations and lipoprotein profiles in diabetic APA hamsters at 6 WAI to reveal the early stage of atherogenesis clinicopathologically. As a result, by biochemical analysis, hyperglycemic APA hamsters showed signs of hypercholesterolemia and hypertriglyceridemia. Low-density lipoprotein (LDL) cholesterol significantly increased, but high-density lipoprotein (HDL) cholesterol significantly decreased. Agarose gel electrophoresis showed an obvious increase in the fractions of chylomicron, LDL and abnormal lipoprotein. Plasma LDL in diabetic animals was in a state more susceptible to oxidization. In addition, a significant increase in glycated LDL was also found in the diabetic animals by enzyme linked immunosorbent assay (ELISA). Moreover, lipid peroxidation product (4-hydroxynonenal (4 HNE))-adducted proteins and advanced glycation end-products (AGE) were immunohistochemically detected in the foam cells of the fatty streaks. These results revealed that diabetic APA hamsters had hyperlipidemia characterized by increases in chylomicron, LDL and abnormal lipoprotein, and suggested that oxidized LDL and/or glycated LDL might be actively uptaken by macrophages and play an important role in the initial stage of atherogenesis.

Topics: Aldehydes; Animals; Aortic Diseases; Arteriosclerosis; Cholesterol, LDL; Cricetinae; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Foam Cells; Glycation End Products, Advanced; Immunohistochemistry; Lipid Peroxidation; Lipids; Lipoproteins; Male

Glycoxidation reactions lead to the formation of permanent, irreversible chemical modifications and cross-links in protein, such as the glycoxidation products carboxymethyllysine (CML) and pentosidine. It has been implicated that CML as well as Amadori products play a role in the formation of superoxidative products, such as H2O2 and advanced glycosylation endproducts in trapping LDL. Therefore, a possible relationship between glycoxidation and lipoperoxidation might exist because oxidized lipoprotein, which has been directly linked to atheroma formation, could be produced by the superoxidative products released from the pathway of CML formation. Using a CML-specific monoclonal antibody (6D12) and a specific antiserum against hexitol-lysine (HL), an Amadori product, we studied the relationship between glycoxidation and lipoperoxidation by determining the aortic CML contents with ELISA and the fluorescence levels of lipoperoxidation side products, malondialdehyde (MDA) and hydroxynonenal (HNE) from STZ-induced diabetic rats and age-matched control rats. The immunohistochemical and ultrastructural changes relevant to glycoxidation and lipoperoxidation were also studied. The CML content measured by ELISA in DM rats was significantly higher than that in the control rats at 28 weeks (n = 11, P < 0.01). The levels of MDA-linked and HNE-linked fluorescence in the DM rats increased in a similar way and were significantly higher than the levels in control rats at 28 weeks (n = 11, both P < 0.01 at 28 weeks). The CML contents correlated with the fluorescence levels of both MDA-linked (n = 19, r = 0.638, P < 0.01) and HNE-linked fluorescence (n = 19, r = 0.629, P < 0.01) only in the DM rats, but not in the control rats. Our immunohistochemical study thus demonstrated that CML was initially formed in the aortic media of diabetic rats in the 16th week of diabetes, localized primarily in the extracellular matrix surrounding the aortic smooth muscle cells after HL occurred early in the 2nd week of diabetes. Consequently, a significant increase in the extracellular matrix and decrease in the area of the SMCs were observed in the aortic media in the DM rats by a morphometrical study. The in vivo results of this study provided the first evidence that CML correlated with fluorescence levels of MDA and HNE, and thus suggested the existence of a close relationship between glycoxidation and lipoperoxidation in vivo. This information is thus considered to shed some new light on

Topics: Aldehydes; Animals; Aorta; Collagen; Diabetes Mellitus, Experimental; Diabetic Angiopathies; Enzyme-Linked Immunosorbent Assay; Glycation End Products, Advanced; Glycosylation; Immunohistochemistry; Lipid Peroxidation; Lysine; Male; Malondialdehyde; Oxidation-Reduction; Rats; Rats, Sprague-Dawley; Streptozocin