8-hydroxy-2--deoxyguanosine and Diabetic-Angiopathies

Because of Westernized life style, diabetes and its complications become one of the most popular diseases in Asian countries as well as Westernized countries. Compared with diabetic microvascular complications, several risk factors such as postprandial hyperglycemia, increased coagulability, chronic inflammation, and genetic risk factors may lead to augment atherosclerosis, are shown to result in diabetic macroangiopathies (acute coronary syndrome, brain infarction, and ASO). Addition to candidate gene approach, genome wide association study (GWAS) successfully elucidated several novel single nuclear polymorphisms (SNP), contributing atherosclerosis. However, these genetic risk factors are still shown to contribute a relatively small part of atherosclerosis. Recently we have determined more than 100 atherosclerosis-related SNPs of around 2,000 subjects with type 2 diabetes. We have shown the combination of two atherosclerosis-prone SNPs highly significantly contribute to carotid atherosclerosis and coronary artery disease in subjects with type 2 diabetes. Also, accumulation of oxygen stress-prone alleles of some SNPs are proven to relate with serum level of 8-OHdG, as oxidative stress marker, carotid IMT, and prevalence of old myocardial infarction. These data clearly indicate that several genetic risk factors as well as conventional risk factors additively or synergistically contribute to diabetic macroangiopathy.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Humans; Oxidative Stress; Polymorphism, Single Nucleotide

Glimepiride, a third generation sulfonylurea (SU), is known to have extrapancreatic effects, but its vascular effect is unclear. We investigated the efficacy of glimepiride in improving arterial stiffness assessed by cardio-ankle vascular index (CAVI) in type 2 diabetic patients, compared with glibenclamide, a conventional SU.. Forty type 2 diabetic patients were randomly assigned to two groups. One group was administered glimepiride 1.5 mg/day, and the other group was administered glibenclamide 1.25 mg/day for 6 months.. No significant difference in hypoglycaemic effect was observed between two groups. CAVI significantly decreased only in glimepiride group (9.4 ± 1.4→8.9 ± 0.8, p < 0.05). Decrease in CAVI was greater in glimepiride group than in glibenclamide group (-0.50 ± 0.98 vs. -0.04 ± 0.57, p = 0.048). Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) decreased in glimepiride group and increased in glibenclamide group, and the changes were significantly different between groups (-1.5 ± 3.5 vs. + 1.8 ± 3.6, p = 0.009); whereas serum lipoprotein lipase mass increased in glibenclamide group and decreased in glibenclamide group, and the changes tended to be different between groups (+ 2.1 ± 19.1 vs. -7.4 ± 19.2, p = 0.096). Change in urinary 8-OHdG was a significant independent predictor for change in CAVI in all subjects.. These results suggest that glimepiride improves CAVI compared with glibenclamide. Reduced oxidative stress and improved insulin resistance may contribute to the improvement of CAVI by glimerpiride.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Ankle; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Glyburide; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Lipids; Male; Middle Aged; Sulfonylurea Compounds; Vascular Resistance; Vascular Stiffness

Haptoglobin (Hp) functions as an antioxidant by binding with haemoglobin. We investigated whether serum Hp has a causal effect on macroangiopathy via Mendelian randomization (MR) analysis with common variants of the Hp gene in Chinese patients with type 2 diabetes.. A total of 5687 type 2 diabetes patients were recruited and genotyped for the Hp gene. Clinical features and vascular imaging tests were applied to diagnose macroangiopathy. The association between common Hp genotypes and macroangiopathy was analyzed in the whole population. Serum Hp levels were measured by enzyme-linked immunosorbent assay in a subset of 935 patients. We individually analyzed the correlations among Hp levels, Hp genotypes and macroangiopathy. Further, 8-hydroxy-2'-deoxyguanosine (8-OHdG), an oxidative marker of DNA damage, was examined to evaluate the levels of oxidative stress.. Common Hp genotypes were correlated with macroangiopathy (OR = 1.140 [95% CI 1.005-1.293], P = 0.0410 for the Hp 1 allele). Serum Hp levels were associated with both common Hp genotypes (P = 3.55 × 10. Our study provides evidence for a causal relationship between serum Hp levels and macroangiopathy in Chinese type 2 diabetes patients by MR analysis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Asian People; China; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; DNA Damage; Female; Gene Frequency; Genetic Predisposition to Disease; Genetic Variation; Haptoglobins; Humans; Male; Mendelian Randomization Analysis; Middle Aged; Oxidative Stress; Phenotype; Risk Factors

To evaluate oxidative damage in leukocytes from patients with type 2 diabetes by examining 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels.. Patients with type 2 diabetes and healthy controls were assessed for demographic, clinical and biochemical characteristics. Levels of 8-OHdG in extracted leukocyte DNA were determined by enzyme linked immunosorbent assay.. Of 108 patients with type 2 diabetes (56 with microangiopathy, 52 without) and 65 healthy controls, leukocyte 8-OHdG levels were higher in patients with type 2 diabetes versus controls (median ± interquartile range [IQR], 3.19 ± 2.17 versus 0.38 ± 1.00 ng/ml), and higher in patients with type 2 diabetes and microangiopathy versus those without microangiopathy (median ± IQR, 3.34 ± 1.87 versus 2.71 ± 2.26 ng/ml). Patients with type 2 diabetes and microangiopathy had higher serum creatinine and urinary albumin levels versus those without microangiopathy. Leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria, use of insulin and use of angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) were independently associated with microangiopathy in patients with type 2 diabetes after adjustment for smoking.. Leukocyte oxidative DNA damage was high in patients with type 2 diabetes and microangiopathy. Presence of microangiopathy was associated with leukocyte 8-OHdG levels, duration of type 2 diabetes, albuminuria and use of ACE inhibitors/ARBs or insulin.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Asian People; Case-Control Studies; Demography; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; DNA; DNA Damage; Female; Humans; Leukocytes; Logistic Models; Male; Middle Aged; Multivariate Analysis

Urinary markers of nucleic acid oxidation may be useful biomarkers in diabetes. It has been demonstrated that T2DM patients have an increased level of oxidative DNA damage; however, it is unclear whether increased DNA damage may be related to a greater degree of inflammation and insulin resistance. Thus, the aim of this present study was to investigate the relation of the impact of oxidative DNA damage, assessed by urinary 8-OHdG, on the levels of inflammatory cytokines, as well as insulin resistance. In addition, we also investigated the diagnostic ability of urinary 8-OHdG in the identification of microvascular complications in T2DM.A case-control study, enrolling 22 healthy controls and 54 subjects with T2DM, was performed to evaluate the relation between oxidative DNA damage and interleukin-6 (IL-6), IL-1,tumor necrosis factor-alpha (TNF-α), IL-10, and Homeostasis Model Assessment (HOMA-IR) index. T2DM patients presented higher urinary 8-OHdG, IL-6, IL-1, TNF-α levels and HOMA-IR, and lower IL-10 levels than control subjects. Moreover, urinary 8-OHdG levels were significantly higher in the group T2DM with microvascular complications when compared to the without complications. The areas under the curve for urinary 8-OHdG and urinary albumin were, respectively, 0.836 (P<0.001) and 0.786 (P=0.002). Thus, urinary 8-OHdG has a slightly higher ability to discriminate microvascular complications in T2DM compared with urinary albumin. It was also demonstrated that T2DM patients with higher median of urinary 8-OHdG had significantly elevated levels of IL-6, TNF-α and HOMA-IR, and decreased IL-10 levels. Our findings showed that T2DM patients with higher urinary 8-OHdG levels showed a greater inflammatory degree and higher insulin resistance. It is possible to speculate that T2DM patients present a cascade of events as increasing metabolic abnormalities such as insulin resistance and inflammatory activation, as well as increased ROS generation factors that may contribute directly to greater oxidative DNA damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Biomarkers; Case-Control Studies; Cytokines; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; DNA Damage; Female; Humans; Insulin Resistance; Linear Models; Male; Microvessels; Middle Aged; Oxidative Stress; ROC Curve

Vascular endothelial growth factor (VEGF), which is associated with the stimulation of angiogenesis and collateral vessel synthase, is one of the crucial factors involved in cardiac remodeling in type 2 diabetes.. We investigated VEGF inhibition by dRK6 on the heart in an animal model of type 2 diabetes. Male db/db and db/m mice either were treated with dRK6 starting at 7 weeks of age for 12 weeks (db/db-dRK6 and db/m-dRK6) or were untreated.. Cardiac dysfunction and hypertrophy were noted by echocardiogram and molecular markers in the db/db-dRK6 mice. The presence of diabetes significantly suppressed the expression of VEGF receptor (VEGFR)-1 and VEGFR-2, phospho-Akt, and phospho-endothelial nitric oxide synthase (eNOS) in the heart. In db/db-dRK6 mice, dRK6 completely inhibited VEGFR-2, phospho-Akt, and phospho-eNOS expression, whereas no effect on VEGFR-1 was observed. Cardiac fibrosis, microvascular scarcity associated with an increase in apoptotic endothelial cells, and inflammation were prominent, as well as increase in antiangiogenic growth factors. Cardiac 8-hydroxy-deoxyguanine and hypoxia-inducible factor-1alpha expression were significantly increased. No such changes were found in the other groups, including the db/m-dRK6 mice. The number of apoptotic human umbilical vein endothelial cells was increased by dRK6 in a dose-dependent manner only at high glucose concentrations, and this was associated with a decrease in phospho-Akt and phospho-eNOS related to oxidative stress.. Our results demonstrated that systemic blockade of VEGF by dRK6 had deleterious effects on the heart in an animal model of type 2 diabetes; dRK6 induced downregulation of the VEGFR-2 and Akt-eNOS axis and enhancement of oxidative stress.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Cardiomegaly; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Echocardiography; Endothelium, Vascular; Fibrosis; Heart Diseases; Immunohistochemistry; Inflammation; Intercellular Adhesion Molecule-1; Male; Mice; Mice, Inbred Strains; Nitric Oxide Synthase Type III; Oligopeptides; Proto-Oncogene Proteins c-akt; Thrombospondin 1; Vascular Endothelial Growth Factor A

Diabetes mellitus is characterized by oxidative stress, which in turn determines endothelial dysfunction. Gliclazide is a sulphonylurea antidiabetic drug with antioxidant effects due to its azabicyclo-octyl ring. It has been reported to potentially protect the vasculature through improvements in plasma lipid levels and platelet function. We hypothesized that gliclazide has a beneficial effect on endothelial function in Goto-Kakizaki rats (GK), an animal model of type 2 diabetes fed an atherogenic diet for 4 months. We evaluated the influence of gliclazide on both metabolic and oxidative status and NO-mediated vasodilation. GKAD rats showed increased oxidative stress and impaired endothelium-dependent vasodilation. GKAD rats treated with gliclazide showed increased sensitivity to NO-mediated vasodilation, a significant decrease in fasting glycemia and insulinemia, and a significant decrease in systemic oxidative stress. In conclusion, our results suggest that gliclazide treatment improves NO-mediated vasodilation in diabetic GK rats with dyslipidemia probably due to its antioxidant effects, although we cannot rule out substantial benefits due to a reduction in fasting blood glucose. The availability of a compound that simultaneously decreases hyperglycemia, hyperinsulinemia, and inhibits oxidative stress is a promising therapeutic candidate for the prevention of vascular complications of diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcholine; Animals; Antioxidants; Body Weight; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Dietary Fats; Disease Models, Animal; Dyslipidemias; Gliclazide; Hypoglycemic Agents; Nitric Oxide; Oxidative Stress; Rats; Rats, Mutant Strains; Rats, Wistar; Vasodilation; Vasodilator Agents

Individuals with type 2 diabetes exhibit higher DNA damage and increased risk of cardiovascular disease (CVD). However, mechanisms underlying the association between DNA damage and development of type 2 diabetes and CVD are not understood. We sought to link peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PPARGC1A), a master transcriptional regulator of mitochondrial oxidative phosphorylation and cellular energy metabolism, with DNA damage, type 2 diabetes, and CVD.. We measured DNA damage as urinary 8-hydroxydeoxyguanosine (8-OHdG) concentration and examined the relationship between nine PPARGC1A genetic variants, DNA damage, type 2 diabetes, and self-reported CVD in 959 participants of the Boston Puerto Rican Health Study.. With respect to urinary 8-OHdG, PPARGC1A variants showed significant association, and PPARGC1A haplotypes exhibited significant association after correction for multiple testing. Two independent PPARGC1A variants associated significantly with type 2 diabetes (odds ratios [ORs] 1.35 and 2.46; P = 0.045 and <0.001). Carriers of minor alleles of two other PPARGC1A variants, both in strong linkage disequilibrium and associated with lower DNA damage, showed lower prevalence of CVD (ORs 0.53 and 0.65; P = 0.030 and 0.175). Moreover, we found that physical activity correlated negatively with DNA damage.. It is plausible that low physical activity combined with risk haplotyes contribute to the high prevalence of type 2 diabetes in this population. We propose that PPARGC1A influences development of type 2 diabetes and CVD via DNA damage. Increasing physical activity, which induces PPARGC1A expression, is a potential strategy to slow DNA damage, thereby decreasing the risk of CVD for individuals with type 2 diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Biomarkers; Boston; Cardiovascular Diseases; Deoxyguanosine; Diabetes Mellitus; Diabetes Mellitus, Type 2; Diabetic Angiopathies; DNA Damage; Exons; Female; Gene Frequency; Genetic Variation; Heat-Shock Proteins; Humans; Introns; Male; Middle Aged; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Polymorphism, Single Nucleotide; Puerto Rico; Risk Factors; Transcription Factors

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). Here we demonstrate that hyperglycemia-induced production of ROS is abrogated by inhibitors of mitochondrial metabolism, or by overexpression of uncoupling protein-1 or manganese superoxide dismutase. Normalization of mitochondrial ROS production by each of these agents prevents glucose-induced activation of PKC, formation of AGE, and accumulation of sorbitol in bovine vascular endothelial cells. We also claim that 8-hydroxydeoxyguanosine, which represents mitochondrial oxidative damage was elevated in patients with either retinopathy, albuminuria or increased intima-media thickness of carotid arteries. These results suggest that hyperglycemia induces mitochondrial ROS production, and which can associate to the pathogenesis of diabetic vascular complications.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Citric Acid Cycle; Deoxyguanosine; Diabetic Angiopathies; Humans; Mitochondria; Models, Biological; Reactive Oxygen Species

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

To evaluate the association between the C242T polymorphism of the p22 phox gene, an essential component of NAD(P)H oxidase in the vasculature, with intima-media thickness (IMT) of the carotid artery and risk factors for atherosclerosis in type 2 diabetic subjects.. C242T polymorphism of the p22 phox gene was detected by polymerase chain reaction-restriction fragment-length polymorphism in 200 Japanese type 2 diabetic subjects and 215 nondiabetic subjects. We examined the association with this mutation and carotid atherosclerosis as well as the patients' clinical characteristics and the level of 8-hydroxy-2'deoxyguanosine (8-OHdG) as an index of oxidative DNA damage.. The diabetic subjects with the TC+TT genotypes displayed a significantly lower average IMT (1.13 +/- 0.31 vs. 1.31 +/- 0.34 mm; P = 0.0099) and a not significantly lower serum 8-OHdG level than those with the CC genotype, despite no difference in the risk factors. Stepwise multiple regression analysis showed that the risk factors for increased IMT in the diabetic subjects were systolic blood pressure (P = 0.0042) and p22 phox CC genotype (P = 0.0151). In nondiabetic subjects, the average IMT of the TC+TT group was not different from that of the CC group (0.85 +/- 0.14 vs. 0.94 +/- 0.30 mm, P = 0.417). Fasting plasma insulin concentration (41.4 +/- 15.6 vs. 64.2 +/- 59.4 pmol/l, P = 0.0098) and insulin resistance index of homeostasis model assessment (HOMA-R) (1.58 +/- 0.66 vs. 2.60 +/- 2.56, P = 0.0066) were significantly lower in the TC+TT group than in the CC group.. These results show that the C242T mutation in the p22 phox gene is associated with progression of asymptomatic atherosclerosis in the subjects with type 2 diabetes and is also associated with insulin resistance in nondiabetic subjects.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Asian People; Carotid Arteries; Carotid Artery Diseases; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Genetic Predisposition to Disease; Genetic Variation; Genotype; Humans; Insulin; Insulin Resistance; Japan; Male; Membrane Transport Proteins; Middle Aged; NADPH Dehydrogenase; NADPH Oxidases; Phosphoproteins; Polymorphism, Genetic; Risk Factors; Tunica Intima; Tunica Media; Ultrasonography

To evaluate urinary 8-hydroxydeoxyguanosine (8-OHdG) as a marker for the progression of diabetic macroangiopathic complications.. 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]. In addition, the patients from the Kumamoto Study were further evaluated regarding the effect of intensive insulin therapy on urinary 8-OHdG excretion.. The urinary 8-OHdG:creatinine ratio (U8-OHdG) was 2.5-fold higher in patients with increased HbA(1c) than in those with normal HbA(1c) (P < 0.05). In addition, U8-OHdG was 2.3-fold higher in patients with increased IMT (P < 0.005). A similar result was observed between U8-OHdG and CHD risk score (P < 0.01). U8-OHdG was significantly higher in patients with simple retinopathy (P < 0.05) and those with advanced retinopathy (P < 0.01) than in patients without retinopathy. Similarly, U8-OHdG was significantly higher in patients with albuminuria (P < 0.01). Furthermore, in the Kumamoto Study, U8-OHdG was significantly lower in the multiple insulin injection therapy group compared with the conventional insulin injection therapy group (P < 0.01).. Hyperglycemia independently increases 8-OHdG in patients with type 2 diabetes. 8-OHdG is a useful biomarker of not only microvascular but also macrovascular complications in patients with type 2 diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Albuminuria; Biomarkers; Carotid Artery, Common; Creatinine; Deoxyguanosine; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Retinopathy; Drug Administration Schedule; Female; Humans; Insulin; Male; Middle Aged; Risk Factors; Tunica Intima; Tunica Media

Increased production of reactive oxygen species (ROS) and lipid peroxidation may contribute to vascular complications in diabetes. to test whether DNA is also oxidatively damaged in diabetes, we measured 8-hydroxydeoxyguanosine (8-OHdG), an indicator of oxidative damage of DNA, in mononuclear cells.. For this laboratory-based study, 12 patients with insulin-dependent diabetes mellitus (IDDM) and 15 patients with non-insulin-dependent diabetes mellitus (NIDDM) were matched by age with ten healthy volunteers each. DNA was extracted from mononuclear cells from whole blood. 8-OHdG was assayed by high-pressure liquid chromatography, and ROS were assayed by chemiluminescence.. IDDM and NIDDM patients had significantly higher median concentrations (p , 0.001, U test) of 8-OHdG in their mononuclear cells than their corresponding controls (in fmol/micrograms DNA): 128.2 (interquartile range 96.0-223.2) and 95.2 (64.0-133.5) vs 28.2 (21.7-43.4) and 21.9 (18.0-24.4), respectively. ROS generation by mononuclear cells was also significantly greater (p < 0.01) in diabetic patients than in their controls (in mV): 238.0 (107.0-243.0) and 101.3 (66.0-134.0) vs 69.5 (49.8-91.9) and 56.0 (38.8-62.5), respectively.. IDDM and NIDDM patients showed greater oxidative damage to DNA, with increased generation of ROS, than controls. Such changes might contribute to accelerated aging and atherogenesis in diabetes and to the microangiopathic complications of the disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Case-Control Studies; Chromatography, High Pressure Liquid; Deoxyguanosine; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Angiopathies; DNA; DNA Damage; Humans; Leukocytes, Mononuclear; Lipid Peroxidation; Luminescent Measurements; Middle Aged; Reactive Oxygen Species