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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diabetes mellitus has assumed epidemic proportions in most parts of the world, and it is a major source of morbidity in developed countries. In addition, in several instances, diabetes is associated with a variety of metabolic abnormalities, including abdominal obesity, insulin resistance, hypertension, dyslipidemia, and hyperglycemia. There is considerable evidence that hyperglycemia causes the generation of reactive oxygen species (ROS), ultimately leading to increased oxidative stress in a variety of tissues. In the absence of an appropriate compensatory response by the endogenous antioxidants, such as vitamins C and E, catalase, glutathione, and superoxide dismutase, oxidative stress dominates, resulting in the activation of stress-sensitive intracellular signaling pathways. One of the major consequences is the generation of gene products that cause cellular damage and are ultimately responsible for the late complications of diabetes. The ability of antioxidants to protect against the effects of hyperglycemia in vitro, along with the clinical benefits often reported following antioxidant therapy, supports a causative role of oxidative stress in mediating and/or worsening these abnormalities. This review will focus on the critical assessment of the literature as it relates to the association between oxidative stress and diabetes, followed by the role of oxidative stress in the complications of type 2 diabetes mellitus. Finally, a review of the use of the antioxidant vitamin E will be provided in diabetic patients by assessing and evaluating some of the clinical trials in the literature.
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PMID:The use of vitamin E in type 2 diabetes mellitus. 1749 41

Succinic acid monoethyl ester (EMS) was recently proposed as an insulinotropic agent for the treatment of non-insulin dependent diabetes mellitus. In the present study the effect of EMS and metformin on erythrocyte membrane bound enzymes and antioxidants activity in plasma and erythrocytes of streptozotocin-nicotinamide induced type 2 diabeteic model was investigated. Succinic acid monoethyl ester was administered intraperitonially for 30 days to control and diabetic rats. The effect of EMS on glucose, insulin, hemoglobin, glycosylated hemoglobin, TBARS, hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (Gpx), glutathione-S-transferase (GST), vitamins C and E, reduced glutathione (GSH) and membrane bound enzymes were studied. The effect of EMS was compared with metformin, a reference drug. The levels of glucose, glycosylated hemoglobin, TBARS, hyderoperoxide, and vitamin E were increased significantly whereas the level of insulin and hemoglobin, as well as antioxidants (SOD, CAT, Gpx, GST, vitamin C and GSH) membrane bound total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase were decreased significantly in streptozotocin-nicotinamide diabetic rats. Administration of EMS to diabetic rats showed a decrease in the levels of glucose, glycosylated hemoglobin, lipid peroxidation markers and vitamin E. In addition the levels of insulin, hemoglobin, enzymic antioxidants, vitamin C, and GSH and the activities of membrane bound enzymes also were increased in EMS and metformin treated diabetic rats. The present study indicates that the EMS possesses a significant beneficial effect on erythrocyte membrane bound enzymes and antioxidants defense system in addition to its antidiabetic effect.
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PMID:Beneficial effect of succinic acid monoethyl ester on erythrocyte membrane bound enzymes and antioxidant status in streptozotocin-nicotinamide induced type 2 diabetes. 1753 13

C-reactive protein (CRP) is one of the acute-phase proteins in inflammation and CRP serum concentrations are therefore of interest. Data for high-sensitivity CRP (hs-CRP) with a low detection limit of approximately 0.04 mg/L have become available over the past decade and research has shown a link between high concentrations of hs-CRP and obesity as well as smoking. Expanded adipose tissue is in fact known to secrete proinflammatory cytokines which enhance hepatic synthesis of CRP. Moderate alcohol consumption and high physical activity have been associated with low levels of hs-CRP, but the evidence in these cases is not conclusive. It has been suggested that hs-CRP is an independent marker of the risk of cardiovascular disease, but the predictive capacity remains controversial. However, many prospective studies have observed increased risk of type 2 diabetes mellitus associated with high concentrations of hs-CRP, independent of obesity and other cardiovascular risk factors. On the other hand, no measurable increase in the risk associated with high levels of hs-CRP was observed with multivariate adjustment in several studies. A number of authors have reported that high concentrations of hs-CRP are associated with increased risks of colorectal and other cancers, but the findings again are inconsistent. Diet and hs-CRP are also of increasing research interest. High intakes of carotenoids and vitamin C, but not of vitamin E, seem to decrease the level of circulating hs-CRP. In addition, high consumption of vegetables and fruit are associated with lower levels of circulating hs-CRP, perhaps by exerting anti-inflammatory effects. Both mechanistic and epidemiologic studies regarding dietary factors and low-grade inflammation are necessary to add to our knowledge of dietary influence on chronic disease development.
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PMID:Impact of C-reactive protein on disease risk and its relation to dietary factors. 1769 26

The objective of our study was to evaluate the effects of the administration of two dosages of vitamin C (Vit-C) (0.5 and 1g/day, vs. placebo) in elderly patients with type 2 diabetes mellitus on the intracellular levels of Vit-C and glutathione, and on the lipid peroxidation markers and vitamin E (Vit-E) content of low-density lipoprotein (LDL) and on LDL susceptibility to gamma radiolysis-induced peroxidation. Thirty-six patients were randomized into three groups. In patients on 0.5 g Vit-C/day versus the placebo group, a significant increase in cellular reduced glutathione level was observed (0.60+/-0.26 vs. 0.33+/-0.27). In patients on 1 g Vit-C/day versus placebo, a significant increase was also observed in cellular reduced glutathione (0.93+/-0.70 vs. 0.33+/-0.27), in Vit-C (5.66+/-2.00 vs. 2.72+/-1.88) and in vitamin E content of LDL (1.98+/-0.38 vs. 1.48+/-0.40). No change was observed in either group in basal levels of lipid peroxidation markers and in the susceptibility of LDL to peroxidation provoked by gamma-radiolysis. In conclusion, Vit-C has a dose-dependent effect on the cellular contents of antioxidants and on vitamin E content of LDL in elderly patients with type 2 DM. These changes are not sufficient to decrease the LDL susceptibility to peroxidation.
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PMID:Effects of vitamin C supplementation on antioxidants and lipid peroxidation markers in elderly subjects with type 2 diabetes. 1807 12

Polycystic ovary syndrome (PCOS) is a condition that involves the excess production of androgens. It affects up to 10% of all American women and can lead to the development of acne, hirsutism, and infertility. It has also been associated with coronary heart disease, diabetes, and metabolic syndrome. Over half of the women who are diagnosed with PCOS are overweight or obese. Recommendations are made for overweight/obese women to lose weight via diet and exercise. Women with PCOS should also consider maintaining a diet that is patterned after the type 2 diabetes diet. This diet includes an increase in fiber and a decrease in refined carbohydrates, as well as a decrease in trans and saturated fats and an increase in omega-3 and omega-9 fatty acids. Foods that contain anti-inflammatory compounds (fiber, omega-3 fatty acids, vitamin E, and red wine) should also be emphasized. Evidence is provided for the impact of these dietary changes on improvements in the androgen profile of PCOS patients.
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PMID:Polycystic ovary syndrome (PCOS) and other androgen excess-related conditions: can changes in dietary intake make a difference? 1820 65

Diet and nutrition have substantial impact on reducing the incidence of diabetes mellitus, where oxidative stress is an important etiopathological factor. The combined protective role of low dose of naringin (15 mg kg(-1)) and vitamin C (25 mg kg(-1)) and high dose of naringin (30 mg kg(-1)) and vitamin C (50 mg kg(-1)) on streptozotocin (STZ)-induced toxicity was studied in male Wistar rats. To induce type II diabetes mellitus, rats were injected with STZ intraperitoneally at a dose of 45 mg kg(-1) body weight. STZ-induced diabetic rats showed significant increase in blood glucose, water intake, food intake and glycated hemoglobin and significant decrease in plasma insulin, total hemoglobin, body weight and liver glycogen. Diabetic rats also showed significant decrease in the activity of hexokinase and significant increase in the activities of glucose-6-phosphatase and fructose-1,6-bisphosphatase in liver and kidney. The levels of plasma thiobarbituric acid reactive substances, lipid hydroperoxides and vitamin E were elevated while the level of reduced glutathione was decreased in diabetic rats. Glycoprotein components such as hexose, hexosamine, fucose and sialic acid were increased in plasma, liver and kidney of diabetic rats. Oral administration of high doses of naringin (30 mg kg(-1)) and vitamin C (50 mg kg(-1)) to diabetic rats for a period of 21 days normalized all the above-mentioned biochemical parameters. The effect exerted by naringin (30 mg kg(-1)) and vitamin C (50 mg kg(-1)) was similar to the effect exerted by insulin (6 units kg(-1)). Thus, our study shows the antihyperglycemic and antioxidant effects of naringin and vitamin C in STZ-induced type II diabetes mellitus in rats.
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PMID:Combined treatment with naringin and vitamin C ameliorates streptozotocin-induced diabetes in male Wistar rats. 1834 97

The hypotheses were: HISS-dependent insulin resistance (HDIR) accounts for insulin resistance that occurs with aging; HDIR is the initiating metabolic defect that leads progressively to type 2 diabetes and the metabolic syndrome; a synergistic antioxidant cocktail in chow confers protection against HDIR, subsequent symptoms of diabetes, and the metabolic syndrome. Male Sprague Dawley rats were tested at 9, 26, and 52 weeks to determine their dynamic response to insulin, the HISS (hepatic insulin sensitizing substance)-dependent component of insulin action, and the HISS-independent (direct) insulin action using a dynamic insulin sensitivity test. In young rats, the HISS component accounted for 52.3+/-2.1% of the response to a bolus of insulin (50mU/kg) which decreased to 29.8+/-3.4% at 6 months and 17.0+/-2.7% at 12 months. HISS action correlated negatively with whole body adiposity and all regional fat depots (r(2) = 0.67-0.87). The antioxidants (vitamin C, vitamin E, and S-adenosylmethionine) conferred protection of HISS action, fat mass at all sites, blood pressure, postprandial insulin and glucose. Data are consistent with the hypotheses. Early detection and therapy directed towards treatment of HDIR offers a novel therapeutic target.
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PMID:HISS-dependent insulin resistance (HDIR) in aged rats is associated with adiposity, progresses to syndrome X, and is attenuated by a unique antioxidant cocktail. 1853 70

We aimed to investigate whether metformin protects the brain against the oxidative imbalance promoted by type 2 diabetes. This study analyzed the effect of metformin on oxidative stress markers (thiobarbituric acid reactive substances (TBARS), malondialdehyde (MDA) and carbonyl groups), hydrogen peroxide (H(2)O(2)) levels, non-enzymatic antioxidant defenses [reduced (GSH) and oxidized (GSSG) glutathione and vitamin E] and enzymatic antioxidant defenses [glutathione peroxidase (GPx), glutathione reductase (GRed) and manganese superoxide dismutase (MnSOD)] in brain homogenates of diabetic GK rats, a model of type 2 diabetes. For this purpose we compared brain homogenates obtained from untreated GK rats versus GK rats treated with metformin during a period of 4 weeks. Brain homogenates obtained from Wistar rats were used as control. The MDA levels, GPx and GRed activities are significantly higher in untreated GK rats, while TBARS levels, carbonyl groups, glutathione content and vitamin E levels remain statistically unchanged when compared with control rats. In contrast, MnSOD activity and the levels of H(2)O(2) are significantly decreased in untreated GK rats when compared with control animals. However, metformin treatment normalized the majority of the parameters altered by diabetes. We observed that metformin, besides its antihyperglycemic action, induces a significant decrease in TBARS and MDA levels, GPx and GRed activities and a significant increase in GSH levels and MnSOD activity. These results indicate that metformin protects against diabetes-associated oxidative stress suggesting that metformin could be an effective neuroprotective agent.
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PMID:Metformin protects the brain against the oxidative imbalance promoted by type 2 diabetes. 1867 48

The increased flux of polyol pathway induced by hyperglycemia is implicated in the pathogenesis of various complications associated with diabetic, which results in increased oxidative stress. Because oxidative stress causes tissue damage in patients with diabetes, searching for an effective strategy to reduce oxidative stress in clinical setting is important in order to prevent diabetic complications. The aim of this study was to evaluate the effects of aldose reductase inhibition on oxidative stress in patients with type 2 diabetes mellitus. The subjects of this study were 21 patients with type 2 diabetes. We compared the levels of various oxidative stress markers and antioxidants including plasma thiobarbituric acid-reactive substances, malondialdehyde-modified low-density lipoprotein, vitamin E, beta-carotene and lipid hydroperoxides in erythrocytes at baseline with those measured after a 3-month course of epalrestat (150 mg/day), an aldose reductase inhibitor. While administration of epalrestat did not result in significant changes in plasma thiobarbituric acid-reactive substances, malondialdehyde-modified low-density lipoprotein, vitamin E, or beta-carotene, it significantly reduced lipid hydroperoxides in erythrocytes. Given the importance of measuring lipid hydroperoxides in erythrocytes as an index of oxidative stress, these results highlight the potential usefulness of epalrestat in reducing oxidative stress in type 2 diabetes mellitus.
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PMID:Aldose reductase inhibitor, epalrestat, reduces lipid hydroperoxides in type 2 diabetes. 1899 44

This study compares the lipid peroxidation marker urinary thiobarbituric acid reactive substances (TBARS) and antioxidants including plasma alpha-tocopherol (vitamin E), plasma (P-GSH-Px) and erythrocyte glutathione peroxidase (E-GSH-Px) activities, and plasma selenium levels in two groups of type 2 diabetic subjects (both n=20) with a disease duration of < or =2 (GP1) and 4-6 years (GP2), and non-diabetic age and gender-matched control subjects (CG, n=20). The mean (standard deviation [SD]) age of the groups was similar at 41(10) years. Fasting blood and midstream urine samples were obtained from diabetic and non-diabetic subjects attending the diabetic clinic and HbAlc, fructosamine, urine TBARS, total antioxidant (TAS) levels, P-GSH-Px, E-GSHPx and plasma selenium and vitamin E concentrations were measured. HbA1c (%) and fructosamine levels in the GP1 and GP2 diabetic subjects and the controls were 5.75 (0.67), 11.43 (2.01) and 4.33 (0.47), and 3.09 (0.57), 6.09 (1.15) and 1.67 (0.31), respectively (GP1 vs. GP2, GP1 vs. GC and GP2 vs. CG, all P < 0.001). Elevated urinary TBARS (micromol/mmol urinary creatinine) in the GP1, GP2 and GC groups were 2.47 (0.37), 3.73 (0.93) and 1.18 (0.24), respectively (GP1 vs. GP2, GP1 vs. GC and GP2 vs. CG, all P < 0.001). A significant correlation between HbA1c and TBARS was also noted (r2 = 0.894, P < 0.001) but only in the GP2 subjects. TAS levels were only decreased in the GP2 group compared to control values (0.59 [0.18] vs. 1.74 [0.21], P < 0.001). Plasma vitamin E concentrations (micromol/L) of 34.11 (3.31), 9.57 (2.20) and 39.01 (2.91) were observed in the GP1, GP2 and GC groups, respectively (GP1 vs. CG, P < 0.05 and GP1 vs. GP2 and GP vs. CG, both P < 0.001). E-GSH-Px (U/g Hb) and P-GSH-Px (U/L) activities in GP1, GP2 and CG groups were also decreased at 57.04 (4.31), 24.0 (8.94) and 67.6 (4.29), and 6.16 (1.56), 2.67 (0.47) and 8.72 (0.31), respectively (E-GSH-Px: CG vs. GP1, P < 0.01, CG vs. GP2 and GP1 vs. GP2, both P < 0.001; P-GSH-Px: CG vs. GP1, CG vs. GP2 and GP1 vs. GP2, all P < 0.001). Plasma selenium levels (miromol/L) were only significantly decreased in GP2 compared to both GP1 and CG values (0.49 [0.29] vs. 1.67 [0.80] vs. 1.79 [0.26], both P < 0.001). These observations support the suggestion that chronic hyperglycaemia can influence the generation of free radicals, which may lead ultimately to increased lipid peroxidation and depletion of antioxidants, and thereby enhanced oxidative stress in subjects with type 2 diabetes mellitus.
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PMID:The relationship between chronic glycaemic control and oxidative stress in type 2 diabetes mellitus. 1905 8


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