8-hydroxy-2--deoxyguanosine and Diabetes-Mellitus--Type-1

Oxidative stress is involved in the pathogenesis of diabetic kidney disease. We evaluated the association between 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker of DNA oxidative damage, and end-stage renal disease (ESRD) or death in individuals with type 1 diabetes.. Plasma 8-OHdG concentrations were measured at baseline in participants with type 1 diabetes from GENEDIAB (n = 348) and GENESIS (n = 571) cohorts. A follow-up was conducted in 205 and 499 participants for a mean ± SD duration of 8.9 ± 2.3 years and 5.2 ± 1.9 years, respectively. We tested associations between 8-OHdG concentrations and urinary albumin concentration (UAC) or eGFR at baseline, and the risk of ESRD or all-cause mortality during follow-up. Analyses were performed in pooled cohorts.. The highest UAC (geometric mean [95% CI]) was observed in the third 8-OHdG tertile (tertile 1, 9 [6, 13] mg/l; tertile 2, 10 [7, 16] mg/l; tertile 3, 16 [10, 25] mg/l; p = 0.36 for tertile 1 vs tertile 2 and p = 0.003 for tertile 3 vs tertile 1) after adjustment for potential confounding covariates. The lowest eGFR (mean [95% CI]) was observed in the third tertile (tertile 1, 87 [82, 93] ml min. Higher plasma concentrations of 8-OHdG were independently associated with increased risk of kidney disease in individuals with type 1 diabetes, suggesting that this marker can be used to evaluate the progression of diabetic kidney disease.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Cross-Sectional Studies; Deoxyguanosine; Diabetes Mellitus, Type 1; DNA Damage; Female; Follow-Up Studies; Glomerular Filtration Rate; Humans; Kidney Failure, Chronic; Male; Middle Aged; Oxidative Stress; Oxygen; Prospective Studies; Risk Factors; Sensitivity and Specificity

The molecular signaling mechanisms between glomerular cell types during initiation/progression of diabetic kidney disease (DKD) remain poorly understood. We compared the early transcriptome profile between DKD-resistant C57BL/6J and DKD-susceptible DBA/2J (D2) glomeruli and demonstrated a significant downregulation of essential mitochondrial genes in glomeruli from diabetic D2 mice, but not in C57BL/6J, with comparable hyperglycemia. Diabetic D2 mice manifested increased mitochondrial DNA lesions (8-oxoguanine) exclusively localized to glomerular endothelial cells after 3 weeks of diabetes, and these accumulated over time in addition to increased urine secretion of 8-oxo-deoxyguanosine. Detailed assessment of glomerular capillaries from diabetic D2 mice demonstrated early signs of endothelial injury and loss of fenestrae. Glomerular endothelial mitochondrial dysfunction was associated with increased glomerular endothelin-1 receptor type A (Ednra) expression and increased circulating endothelin-1 (Edn1). Selective Ednra blockade or mitochondrial-targeted reactive oxygen species scavenging prevented mitochondrial oxidative stress of endothelial cells and ameliorated diabetes-induced endothelial injury, podocyte loss, albuminuria, and glomerulosclerosis. In human DKD, increased urine 8-oxo-deoxyguanosine was associated with rapid DKD progression, and biopsies from patients with DKD showed increased mitochondrial DNA damage associated with glomerular endothelial EDNRA expression. Our studies show that DKD susceptibility was linked to mitochondrial dysfunction, mediated largely by Edn1-Ednra in glomerular endothelial cells representing an early event in DKD progression, and suggest that cross talk between glomerular endothelial injury and podocytes leads to defects and depletion, albuminuria, and glomerulosclerosis.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Albuminuria; Animals; Antioxidants; Chromatography, High Pressure Liquid; Deoxyguanosine; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Disease Susceptibility; DNA, Mitochondrial; Endothelin-1; Endothelium; Enzyme-Linked Immunosorbent Assay; Female; Flow Cytometry; Humans; Kidney Glomerulus; Male; Mesangial Cells; Mice; Mice, Inbred C57BL; Mice, Inbred DBA; Microscopy, Electron, Scanning; Middle Aged; Mitochondria; Organophosphorus Compounds; Oxygen Consumption; Piperidines; Podocytes; Real-Time Polymerase Chain Reaction; Receptor, Endothelin A; Signal Transduction; Young Adult

To determine whether higher glucose level and systemic oxidative stress decrease mean velocity (MV) index of the central retinal artery (CRA) during flickering light stimulation in type 1 diabetes (T1D).. The study was performed in the period from 2008 to 2015 at the University Eye Clinic in Ljubljana. 41 patients with T1D and 37 participants without diabetes were included. MV in the CRA was measured using Doppler ultrasound diagnostics in basal conditions and during 8 Hz flickering light irritation. The plasma levels of glucose, fructosamine, 8-hydroxy-2'-deoxyguanosine (8-OHdG), triglycerides, cholesterol, and low-density lipoprotein (LDL) were measured.. Patients with T1D had significantly higher levels of blood glucose (P<0.001), fructosamine (P<0.001), and 8-OHdG (P<0.001), but there were no significant differences in triglycerides (P=0.108), cholesterol (P=0.531), and LDL (P=0.645) between the groups. Patients with T1D also had a significantly lower MV index in the CRA (1.11±0.15 vs 1.24±0.23; P=0.010). In the T1D group, a significant negative correlation was found between the level of glucose (r=0.58; P<0.001), fructosamine (r=0.46; P=0.003), 8-OHdG (r=0.48; P=0.002) and the MV index in the CRA. At the same time, in this group fructosamine and 8-OHdG levels had a separate effect on the MV index (adjusted R2=0.38, P<0.001).. Higher glucose levels, the medium-term glucose level, and systemic oxidative stress could importantly reduce retinal vasodilatation during flickering light irritation in patients with T1D.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Aged; Blood Glucose; Deoxyguanosine; Diabetes Mellitus, Type 1; Female; Hemodynamics; Humans; Lighting; Lipids; Male; Middle Aged; Oxidative Stress; Retinal Artery

Previous studies have shown that preventive treatment with the antioxidant, ebselen, in experimental models of type 1 diabetic nephropathy resulted in an attenuation of structural and functional damage in the kidney. However, evidence for the effectiveness of ebselen in late-intervention studies is lacking. Thus, we aimed to investigate the effects of ebselen in attenuating established renal injury in type 1 diabetic nephropathy using the Akita mouse model.. Baseline blood glucose and albumin-to-creatinine ratio (ACR) were measured in wild-type (WT) and heterozygous Akita mice at 9 weeks of age. At 10 weeks of age, WT and Akita mice were randomized to receive either vehicle (5% carboxymethyl cellulose) or ebselen by oral gavage at 10mg/kg twice daily. Kidney and urine were collected after 16 weeks of treatment with ebselen for histological and functional analyses.. At 9 weeks of age, Akita mice displayed well-established renal dysfunction with significant increases in ACR and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels when compared with WT controls. After 16 weeks of treatment with ebselen, oxidative stress, as measured by nitrotyrosine immunostaining and urinary 8-OHdG levels, was significantly reduced in the Akita mice. Furthermore, gene expression of the major reactive oxygen species-producing nicotinamide adenine dinucleotide phosphate enzyme, Nox4, was also reduced by ebselen. However, ebselen had no effect on ACR and glomerulosclerosis.. Chronic treatment with ebselen significantly reduced oxidative stress in the Akita mice. However, ebselen failed to attenuate functional or structural kidney damage in this late-intervention study using the Akita mouse model.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Animals; Antioxidants; Azoles; Deoxyguanosine; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Disease Models, Animal; Isoindoles; Kidney; Male; Mice; NADPH Oxidase 4; NADPH Oxidases; Organoselenium Compounds; Oxidative Stress

Trace elements and oxidative stress are associated with glycemic control and diabetic complications in type 1 diabetes mellitus. In this study, we analyzed the levels of serum copper, zinc, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) and urinary MDA and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in 33 type 1 diabetic patients with optimal and suboptimal glycemic control (HbA1C<9.0%) and 40 patients with poor glycemic control (HbA1C≥9%) and 27 age- and sex-matched non-diabetic controls to evaluate the differences between these markers in different glycemic control states. Diabetic patients, especially poor-glycemic-control subjects (HbA1C≥9%), exhibited significantly lower levels of serum zinc and increased levels of serum copper (and, therefore, increased serum copper-to-zinc ratios), serum SOD, blood MDA, and urinary MDA and 8-OHdG, relative to non-diabetic subjects. Furthermore, significant correlations existed in these patients between the serum copper, serum copper-to-zinc ratio, and urinary MDA (all p<0.001) and the levels of urinary 8-OHdG (p=0.007) and HbA1C. Our results suggest that high serum copper levels and oxidative stress correlate with glycemic control. Therefore, strict glycemic control, decreased oxidative stress, and a lower copper concentration might prevent diabetic complications in patients with type 1 diabetes mellitus.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Blood Glucose; Child; Copper; Deoxyguanosine; Diabetes Mellitus, Type 1; Female; Humans; Male; Malondialdehyde; Oxidative Stress; Trace Elements; Young Adult; Zinc

Increasing evidence showed that telomere length was shorter in age-related diseases, but the mechanism of this phenomenon is still unclear.. To determine whether telomere shortening occurs in Type 1 diabetes (T1D) and Type 2 diabetes (T2D), and explore the effect of antioxidant status on the telomere length.. T2D patients (no.=62), T1D patients (no.=34), and non-diabetic subjects used as control (CTL) (no.=40) were included in this study. Leukocyte telomere length ratio (T/S ratio) was measured using a quantitative PCR and analyzed. Antioxidant status was estimated by human 8-hydroxy-desoxyguanosine quantization. Other biomarkers, such as fasting plasma glucose, fasting insulin, glycated hemoglobin (HbA1c) and lipid profile were also measured.. Compared with CTL group [T/S ratio (mean ± SD), 2.39 ± 0.55], leukocyte telomere length was significantly shorter in T2D group (1.67 ± 0.50) and T1D group (1.77 ± 0.50). 8-OHdG that indicated oxidative stress was significantly higher in T2D (2.99 ± 0.85 ng/ml) and T1D (2.03 ± 0.92 ng/ml) group than in CTL group (0.90 ± 0.46 ng/ml). T/S ratio was significantly negatively correlated with age, waist circumference, waist-to-hip ratio, diastolic blood pressure, fasting plasma glucose, HbA1c, homeostasis model assessment of insulin resistance and 8- OHdG in the whole population. 8-OHdG was independent risk factor for telomere shortening in both T1D (p=0.018) and T2D group (p=0.022).. In our study, shorter telomere length and increased oxidative stress were observed in both T1D and T2D. Older people with central obesity, hyperglycemia, insulin resistance and severe antioxidant status tended to have shorter telomere length. In addition, 8- OHdG was an independent predictor for telomere length for both T1D and T2D patients.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Deoxyguanosine; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Leukocytes; Male; Middle Aged; Oxidative Stress; Telomere

In spite of improvement in obstetrical care, pregnancy in women with type 1 diabetes mellitus is associated with increased perinatal morbidity and mortality. Hyperglycemia during pregnancy causes excessive fetal growth and chronic fetal hypoxia as reflected in increased erythropoietin (EPO) levels in amniotic fluid (AF).. We hypothesized that the degree of fetal hypoxia would correlate with fetal oxidative and nitrosative stress as evidenced ty the concentration of specific biomarkers in AF.. 19 pregnant women with type 1 or insulin-treated gestational diabetes mellitus were studied. AF samples were collected and processed for EPO, meta-tyrosine, nitro-tyrosine and 8-hydroxy-2-deoxiguanosine by chemiluminescent immunoassay and high-performance liquid chromatography coupled to tandem mass spectrometry methods, respectively.. The mean (SD) of the last HbA1c concentration before delivery was 7.7% (1.1). Median gestational age was 258 days (range 231-268). Birth weight was 3,868 ± 695 g with a z-score >2 SD in 47% of the cases. A significant correlation was found between the concentrations of AF EPO and meta-tyrosine/phenylalanine ratio (p < 0.001), nitro-tyrosine (p < 0.01) and 8-oxo-dG/2dG ratio (p < 0.001).. We confirmed that fetuses of type 1 diabetes or insulin-treated gestational diabetes pregnancies experience chronic hypoxia as reflected by increased EPO concentrations in AF near term. Moreover, EPO levels significantly correlated with the concentration of oxidative and nitrosative stress biomarkers in AF. This pro-oxidant status may predispose newborn infants to poor postnatal adaptation and early neonatal complications.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Amniocentesis; Amniotic Fluid; Biomarkers; Birth Weight; Chromatography, High Pressure Liquid; Chronic Disease; Deoxyguanosine; Diabetes Mellitus, Type 1; Diabetes, Gestational; Erythropoietin; Female; Fetal Hypoxia; Gestational Age; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Immunoassay; Infant, Newborn; Insulin; Male; Nitrosation; Oxidative Stress; Pilot Projects; Pregnancy; Pregnancy in Diabetics; Tandem Mass Spectrometry; Tyrosine; Young Adult

Oxidative stress has been implicated in the pathogenesis of diabetes mellitus (DM). Levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), 8-epi-prostaglandin-F(2α) (8-epi-PGF2α), and total protein carbonyls were measured to assess whether DM is associated with altered salivary redox homeostasis.. A total of 215 patients with diabetes and 481 healthy controls were recruited from the Department of Endocrinology at the Jewish General Hospital in Montreal. Levels of oxidative biomarkers were assayed using enzyme-linked immunosorbent assay (ELISA) in whole unstimulated saliva. Associations of the redox data with exposure to insulin, metformin and dietary control were assessed by logistic regression analyses.. We observed (i) significantly higher mean levels of 8-OHdG and protein carbonyls in whole unstimulated saliva of patients with diabetes compared to controls, (ii) higher mean levels of protein carbonyls in type 1 diabetes as well as higher mean levels of 8-OHdG and protein carbonyls in type 2 diabetes compared to controls, (iii) elevated levels of protein carbonyls in diet-controlled patients and in patients with diabetes on insulin and metformin, (iv) elevated levels of 8-OHdG in patients on metformin, and (v) significant associations between subjects with DM and salivary 8-OHdG and protein carbonyls.. DM is associated with increased oxidative modification of salivary DNA and proteins. Salivary redox homeostasis is perturbed in DM and may inform on the presence of the disease and efficacy of therapeutic interventions.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Age Factors; Biomarkers; Deoxyguanosine; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diet, Diabetic; Dinoprost; DNA Damage; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Lipid Peroxidation; Metformin; Oxidation-Reduction; Oxidative Stress; Protein Carbonylation; Saliva; Salivary Proteins and Peptides; Sex Factors

Advanced glycation end products (AGEs) mediate progressive tissue damage in diabetic nephropathy; however, their utility as a noninvasive reliable biomarker of progressive diabetic nephropathy remains to be determined. In this study, we investigated the temporal accumulation of the AGE carboxymethyllysine (CML) at various sites in a model of experimental diabetic nephropathy.. Diabetic rats were followed for 1, 4, 8, 16 and 32 weeks. Glomerular filtration rate and urinary albumin excretion were measured. CML was determined in the plasma, urine, renal cortical mitochondria and cytosol by an in-house ELISA. Gene expression of AGE receptors were quantified by real-time PCR and urinary excretion of 8-hydroxy-2'-deoxyguanosine (8-OHdG) was determined by EIA.. Four weeks after diabetes induction, urinary CML excretion was increased, which preceded the excretion of urinary albumin and continued to rise progressively until 32 weeks. Circulating, mitochondrial and cytosolic CML content and urinary excretion of 8-OHdG were increased 4 weeks after diabetes induction, but did not increase further with diabetes duration. Renal gene expression of AGE receptors was transiently upregulated at 1 week of diabetes, but this was not a sustained phenomenon.. The most informative marker of progressive renal damage linked to the AGE pathway in experimental diabetic nephropathy is urinary excretion of CML, which now warrants clinical investigation as a potential noninvasive sensitive marker of progressive diabetic nephropathy.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Albuminuria; Animals; Biomarkers; Cytosol; Deoxyguanosine; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetic Nephropathies; Gene Expression; Glomerular Filtration Rate; Glycation End Products, Advanced; Kidney Cortex; Lysine; Male; Mitochondria; Rats; Rats, Sprague-Dawley; Receptor for Advanced Glycation End Products; Receptors, Immunologic; RNA, Messenger; Streptozocin; Time Factors

Diabetic hyperglycemia is associated with increased production of reactive oxygen species (ROS). ROS reacts with DNA resulting in various products, such as 8-hydroxydeoxyguanosine (8-OHdG), that excrete in urine owing to DNA repair processes. Urinary 8-OHdG has been proposed as an indicator of oxidative damage to DNA. This study aimed to evaluate relationship between oxidative damage to DNA and protein glycation in patients with Type 1 diabetes. We measured urinary 8-OHdG level in diabetic patients and healthy subjects and discussed its relationship to glycated hemoglobin (HbA(1c)) and glycated serum protein (GSP) levels. Furthermore plasma malondialdehyde (MDA) level monitored as an important indicator of lipid peroxidation in diabetes. We studied 32 patients with Type 1 diabetes mellitus and compared the measured factors with those of 48 age-matched nondiabetic controls. GSP and MDA were measured bycolorimetric assay. Urinary 8-OHdG measurement was carried out using ELISA. In this study urinary 8-OHdG, HbA(1c), plasma MDA, and GSP levels were progressively higher in diabetics than in control subjects (P<0.05). Furthermore we found significant correlation between urinary 8-OHdG and HbA(1c) (P<0.05) in diabetic group. Correlation between fasting blood sugar and GSP were significant. We also found significant correlation between fasting blood sugar and MDA. This case-control study in young diabetic patients showed increased blood glucose and related metabolic disorders result in oxidative stress and oxidative damage to DNA and lipids. Furthermore oxidative damage to DNA is associated to glycemic control level, whereas lipid peroxidation level was not significantly correlated with glycemic control level. J. Clin. Lab. Anal. 24:72-76, 2010. (c) 2010 Wiley-Liss, Inc.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Blood Glucose; Creatinine; Deoxyguanosine; Diabetes Mellitus, Type 1; DNA Damage; Fasting; Female; Glycated Hemoglobin; Glycated Serum Albumin; Glycation End Products, Advanced; Glycosylation; Humans; Hypoglycemia; Lipid Peroxidation; Male; Malondialdehyde; Oxidative Stress; Serum Albumin; Young Adult

Oxidative stress damages DNA in experimental diabetes, and in vitro studies have suggested that it is linked to lipid peroxidation. The objective of the study was to determine whether lipid peroxidation, as assessed with malondialdehyde excretion in recent-onset type 1 diabetes mellitus, is associated with oxidative damage to DNA, as assessed from 8-hydroxydeoxyguanosine excretion. A 3-year longitudinal study of recent-onset type 1 diabetes mellitus was performed. Age- and sex-matched control subjects were studied once. Patients were studied as inpatients at West Virginia University Hospitals. Thirty-seven patients with recent-onset (2-22 months) type 1 diabetes mellitus (male, 10; female, 27) were enrolled in a longitudinal study of oxidative stress. The mean age of the patients was 20 years. None of the patients had hyperlipidemia or were treated with lipid-lowering drugs. Only 1 patient had hypertension and was being treated with beta-adrenergic blocking therapy. Thirty-six patients completed the study; one withdrew after the second evaluation. Lipid peroxidation was assessed by measuring malondialdehyde excretion. Oxidative damage to DNA was assessed from 8-hydroxydeoxyguanosine excretion. Malondialdehyde excretion was increased in the diabetic patients at the first evaluation (2.43 +/- 0.31 micromol/g creatinine), second evaluation (2.34 +/- 0.24), and third evaluation (1.93 +/- 0.15) compared with control subjects (1.51 +/- 0.11) (P < .005). 8-Hydroxydeoxyguanosine excretion, however, was not increased in the diabetic patients. There was no correlation between malondialdehyde and 8-hydroxydeoxyguanosine excretion. We confirmed the presence of oxidative stress in early diabetes as assessed from malondialdehyde excretion. We were unable, however, to confirm oxidative damage to DNA in this cohort of patients; and there was no evidence of a correlation between lipid peroxidation and DNA damage.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Child; Cohort Studies; Deoxyguanosine; Diabetes Mellitus, Type 1; DNA; DNA Damage; Female; Humans; Lipid Peroxides; Longitudinal Studies; Male; Malondialdehyde; Oxidative Stress; Young Adult

To investigate potential mechanisms of oxidative DNA damage in a rat model of type 1 diabetes and in murine proximal tubular epithelial cells and primary culture of rat proximal tubular epithelial cells.. Phosphorylation of Akt and tuberin, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) levels, and 8-oxoG-DNA glycosylase (OGG1) expression were measured in kidney cortical tissue of control and type 1 diabetic animals and in proximal tubular cells incubated with normal or high glucose.. In the renal cortex of diabetic rats, the increase in Akt phosphorylation is associated with enhanced phosphorylation of tuberin, decreased OGG1 protein expression, and 8-oxodG accumulation. Exposure of proximal tubular epithelial cells to high glucose causes a rapid increase in reactive oxygen species (ROS) generation that correlates with the increase in Akt and tuberin phosphorylation. High glucose also resulted in downregulation of OGG1 protein expression, paralleling its effect on Akt and tuberin. Inhibition of phosphatidylinositol 3-kinase/Akt significantly reduced high glucose-induced tuberin phosphorylation and restored OGG1 expression. Hydrogen peroxide stimulates Akt and tuberin phosphorylation and decreases OGG1 protein expression. The antioxidant N-acetylcysteine significantly inhibited ROS generation, Akt/protein kinase B, and tuberin phosphorylation and resulted in deceased 8-oxodG accumulation and upregulation of OGG1 protein expression.. Hyperglycemia in type 1 diabetes and treatment of proximal tubular epithelial cells with high glucose leads to phosphorylation/inactivation of tuberin and downregulation of OGG1 via a redox-dependent activation of Akt in renal tubular epithelial cells. This signaling cascade provides a mechanism of oxidative stress-mediated DNA damage in diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acetylcysteine; Animals; Cells, Cultured; Deoxyguanosine; Diabetes Mellitus; Diabetes Mellitus, Type 1; DNA Damage; DNA Glycosylases; Glucose; Hydrogen Peroxide; Immunoblotting; Immunohistochemistry; Kidney; Mice; Oncogene Protein v-akt; Oxidative Stress; Phosphorylation; Rats; Reactive Oxygen Species; Tuberous Sclerosis Complex 2 Protein; Tumor Suppressor Proteins

The effects of diabetes mellitus on male reproductive health have not been clearly defined. A previous publication from this group reported significantly higher levels of nuclear DNA fragmentation and mitochondrial DNA deletions in spermatozoa from men with type 1 diabetes. This study compared semen profiles, sperm DNA fragmentation and levels of oxidative DNA modification in spermatozoa of diabetic and non-diabetic men. Semen samples from 12 non-diabetic, fertile men and 11 type 1 diabetics were obtained and subjected to conventional light microscopic semen analysis. Nuclear DNA fragmentation was assessed using an alkaline Comet assay and concentrations of 7,8-dihydro-8-oxo-2-deoxyguanosine (8-OHdG), an oxidative adduct of the purine guanosine, were assessed by high-performance liquid chromatography. Conventional semen profiles were similar in both groups, whilst spermatozoa from type 1 diabetics showed significantly higher levels of DNA fragmentation (44% versus 27%; P < 0.05) and concentrations of 8-OHdG (3.6 versus 2.0 molecules of 8-OHdG per 10(5) molecules of deoxyguanosine; P < 0.05). Furthermore, a positive correlation was observed between DNA fragmentation and concentrations of 8-OHdG per 10(5) molecules of deoxyguanosine (rs = 0.7, P < 0.05). The genomic damage evident in spermatozoa of type 1 diabetics may have important implications for their fertility and the outcome of pregnancies fathered by these individuals.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Case-Control Studies; Deoxyguanosine; Diabetes Mellitus, Type 1; DNA Fragmentation; Humans; Male; Oxidative Stress; Semen; Spermatozoa

Involvement of oxidative stress in the pathogenesis of diabetic vascular complications has been proposed. However, there are few methods to determine the status of oxidative stress both directly and quantitatively in young patients with type 1 diabetes.. A total of 27 young patients with type 1 diabetes (mean age +/- SD, 12.6 +/- 4.2 years) with normal renal function and 38 healthy control subjects (13.0 +/- 4.6 years) were investigated. Early morning voiding urine samples were collected. The concentrations of acrolein-lysine adducts, 8-hydroxy-2'-deoxyguanosine (8-OHdG) were determined using competitive enzyme-linked immunosorbent assay, and nitric oxide metabolites were measured using the colorimetric, non-enzymatic assay.. Urinary concentrations of 8-OHdG, but not acrolein-lysine adducts and nitric oxide metabolites, were significantly increased in the diabetic group. For diabetic patients, microalbuminuria was significantly correlated with higher concentrations of all three markers. Hemoglobin A(1c) values were significantly correlated with 8-OHdG values.. These findings indicate that increased oxidative stress and the risk of vascular complications may be present at early stages of type 1 diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adolescent; Adult; Biomarkers; Child; Deoxyguanosine; Diabetes Mellitus, Type 1; Female; Humans; Male; Oxidative Stress

Increased production of advanced glycosylation end products (AGEs) and augmented oxidative stress may contribute to vascular complications in diabetes. Little is known about the formation and accumulation of AGEs in young patients with type 1 diabetes. The aim of the present study was to investigate whether AGE production and oxidative stress are augmented in young patients with type 1 diabetes at early clinical stages of the disease. Urine samples of 38 patients with type 1 diabetes [mean age (+/-SD), 12.8 +/- 4.5 y; diabetes duration, 5.7 +/- 4.3 y; HbA1c, 8.0 +/- 1.6%; urinary albumin excretion, 12.6 +/- 14.4 mg/g creatinine (Cr)] and those of 60 age-matched healthy control subjects were assayed for AGEs, pentosidine and pyrraline, and markers of oxidative stress, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and acrolein-lysine. Of these four markers, urinary concentrations of pentosidine, 8-OHdG, and acrolein-lysine were significantly higher in the patients with diabetes than in the healthy control subjects. For the patient group, pentosidine correlated significantly with 8-OHdG and acrolein-lysine, and pyrraline correlated significantly with acrolein-lysine. Urinary pentosidine, 8-OHdG, and acrolein-lysine but not pyrraline correlated significantly with urinary albumin excretion. Patients with microalbuminuria (> or =15 mg/g Cr) showed significantly higher levels of all four markers than did normoalbuminuric patients and control subjects. The present study indicates that accumulation of AGEs, whose formation is closely linked to oxidative stress, and resultant endothelial dysfunction may start early in the course of type 1 diabetes. This means that the risk of vascular complications may be present at an early age and that the best possible glycemic control should be emphasized from the diagnosis of diabetes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Acrolein; Adolescent; Adult; Arginine; Child; Child, Preschool; Creatinine; Deoxyguanosine; Diabetes Mellitus, Type 1; Female; Glycation End Products, Advanced; Humans; Lysine; Male; Norleucine; Oxidative Stress; Pyrroles; Regression Analysis

Considering that increased oxidative stress induced by hyperglycaemia plays a possible role in the pathogenesis of diabetic complications and that mitochondrial DNA (mDNA) is thought to be more vulnerable than nuclear DNA, we investigated what somatic mutations actually occur in the mDNA of diabetic patients. We also studied the relations between those mutations and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) which is known to increase considerably in people with diabetes.. We identified somatic mutations by subcloning and sequencing two segments of mDNA [control region (nt 15996-16401) and the segment encompassing t-RNA(Leu(UUR))(nt 3149-3404)] in the peripheral blood cells of six diabetic women and control subjects matched for age and sex. This was done in 20 colonies each. In each case we also assayed urinary 8-OHdG.. No difference in the aggregate somatic mutational burden of mDNA was found between patients and control subjects. However, the incidence of somatic transversion mutations in mDNA was significantly higher in diabetic patients than in control subjects (13.93+/-4.57 x 10(-5) vs 1.27+/-1.27 x 10(-5) mutations per base pair; p=0.031, according to Mann-Whitney U-test). There was no significant difference in transition mutations. A correlation was found between the transversion mutational burden and HbA(1)c values, but not between it and 8-OHdG content in the urine.. We showed that somatic transversion point mutations of mDNA increase in diabetic patients. Such transversion mutations can become a new biomarker for mDNA damage associated with hyperglycaemia and possibly caused by oxidative stress but not reflected by urinary 8-OHdG.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Adult; Base Sequence; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; DNA, Mitochondrial; Female; Guanine; Humans; Hyperglycemia; Middle Aged; Mutation; Polymerase Chain Reaction; Reference Values

1. The role of oxidative stress in the pathogenesis of the diabetic state is being investigated extensively. Although oxidative stress has been reported in terms of glycoxidation, protein oxidation and DNA oxidation in diabetes mellitus, oxidation parameters have not been determined in parallel on the same study population.2. We studied 24 patients with diabetes mellitus (14 patients with Type I diabetes with a mean age of 62.3+/-6.3 years and 10 patients with Type II diabetes aged 67.3+/-5.9 years) and compared them with age-matched non-diabetic controls. Urinary o-tyrosine, 8-hydroxy-2'-deoxyguanosine and pentosidine measurements by HPLC were made on two occasions (t1 and t2).3.A clear statistical difference was found between diabetic patients and controls at t1 or t2 for 8-hydroxy-2'-deoxyguanosine and pentosidine, but not for o-tyrosine. No significant correlations were found between clinical and other laboratory parameters except high-density lipoprotein and uric acid. We revealed significantly increased glycoxidation and DNA oxidation in patients with Type I and Type II diabetes, but protein oxidation was not different from controls.4. The finding of increased glycoxidation reflects increased oxidation of the carbohydrate moiety, whereas the increased levels of oxidized DNA may also be interpreted as due to increased DNA repair. The increased 8-hydroxy-2'-deoxyguanosine does not indicate the generation of an individual active oxygen species, but DNA could have been oxidized simply by alkenals from lipid peroxidation, as e.g. malondialdehyde. As no difference in protein oxidation (i.e. o-tyrosine) between diabetics and controls could be revealed, the oxidation of DNA by hydroxyl radical attack is unlikely, as o-tyrosine was proposed as a marker for hydroxyl radical attack. Therefore, the message is that increased glycoxidation can be confirmed, protein oxidation does not appear to take place and increased DNA oxidation is still not proven, as increased 8-hydroxy-2'-deoxyguanosine may simply reflect repair.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Aged; Arginine; Biomarkers; Case-Control Studies; Chromatography, High Pressure Liquid; Deoxyguanosine; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; Lysine; Middle Aged; Oxidative Stress; Statistics, Nonparametric; Tyrosine

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