Oxidative stress in non-insulin-dependent diabetes mellitus (NIDDM) patients

Diabetes mellitus is a metabolic disorder characterized by hyperglycemia. The oxidative stress in diabetes was greatly increased due to prolonged exposure to hyperglycemia and impairment of oxidant/antioxidant equilibrium. Proteins and lipids are among the prime targets for oxidative stress. In the present study, the oxidative stress was evaluated in 55 diabetic patients and 40 healthy subjects by measuring the levels of protein oxidation, lipid peroxidation and some enzymatic and nonenzymatic antioxidants. The oxidative products of protein (PCG) and lipid peroxidation (MDA) and nitric oxide levels in plasma of NIDDM patients were significantly increased. However, the levels of enzymatic (GPx, SOD, catalase in RBC) and nonenzymatic (β-carotene, retinol, vitamin C & E and uric acid) antioxidants of RBC showed a significant decrease in NIDDM patients compared to normal subjects. Serum protein analysis by polyacrylamide gel electrophoresis (PAGE) showed the significant difference in the ceruloplasmin, transferrin, albumin, retinal binding protein, etc. in diabetic patients compared to healthy controls. In conclusion, the results suggest that increased protein oxidation, lipid peroxidation and NO levels, decreases the levels of enzymatic and nonenzymatic antioxidants and playing a major role in diabetic complications.     

Prevalence and incidence trends of non-insulin-dependent diabetes mellitus (NIDDM) in the population of the GDR

Trends of prevalence and incidence rates of non-insulin-dependent diabetes mellitus (non-insulin-treated diabetes mellitus) were assessed in the population of the GDR based upon the National Diabetes Register and the Official Statistical Year Book as sources for the calculations. Within the 25-year follow-up period 1960-1984 the prevalence rose from 4.39%; to 31.95%; the incidence rate from 1.04%; to 3.57%. Age-dependence of the specific rates is characterized by their continuous rise above the age of 30 years reaching the peak prevalence of 146.6%; in 75- to 80-year-olds, that of 14.1%, for the incidence in people aged 70 to 75 years. A significant male preponderance was confirmed between the ages of 30 and 50 years, a significant overwhelming of female NIDDM in the age groups 60 to 90 years. Based on demonstrated correlations between the changes of living standard parameters and the epidemiological trend of NIDDM the conclusion is drawn that overnutrition and reduced muscular activity mainly account for the rise of diabetes morbidity in the population of the GDR.     

肌糖原合成酶基因多态性与糖尿病及其合并高血压的关系

目的研究肌糖原合成酶基因与非胰岛素依赖型糖尿病（ＮＩＤＤＭ）及其合并高血压的关系。方法采用限制性内切酶Ｘｂａｌ对肌糖原合成酶基因片段的聚合酶链反应（ＰＣＲ）产物酶解的方法，观察１６４例ＮＩＤＤＭ（包括６２例合并高血压病人）的糖原合成酶基因多态性。结果肌糖原合成酶基因型（Ａ１／Ａ１，Ａ１／Ａ２）和等位基因（Ａ１，Ａ２）均与ＮＩＤＤＭ无关，而ＮＩＤＤＭ合并高血压者Ａ２等位基因频率明显高于血压正常的ＮＩＤＤＭ者（Ｐ＜０．０５）。结论糖原合成酶基因多态性作为一种标志，提示与其连锁的基因可能参与ＮＩＤＤＭ病人的高血压的发病。     

Tissue-type plasminogen activator and its inhibitor (PAI-1) in plasma in cases of non-insulin-dependent diabetes mellitus (NIDDM)

Parameters of fibrinolysis, including plasminogen, alpha 2 plasmin-inhibitor (alpha 2 PI), tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) antigens, and fibrinogen were assayed in 53 patients (28 women and 27 men; mean age: 64 years, age range: 32-87 years) with non-insulin-dependent diabetes mellitus (NIDDM). The control group was similarly aged (mean age: 60.4 years, age range: 38-81). The levels of t-PA and t-PA/PAI-1 ratio of the diabetic group (mean +/- SD; 9.8 +/- 4.3 ng/ml, 0.94 +/- 0.47, respectively) were significantly higher than that of the control group (5.5 +/- 2.5 ng/ml, 0.51 +/- 0.23, respectively). The increased levels of t-PA antigen and t-PA/PAI-1 ratio in diabetics mean that free t-PA has been released. However, there was no significant difference in the level of PAI-1 between the diabetic group (12.9 +/- 6.4 ng/ml) and the control group (12.1 +/- 5.6 ng/ml). Levels of fibrinogen, plasminogen and alpha 2 PI in plasma were not different in the two groups. Duration of the disease, levels of glycosylated hemoglobin, differences in treatment and presense of diabetic nephropathy or retinopathy did not affect the fibrinolytic parameters. The levels of fibrinogen was higher in those with nephropathy than in the diabetics without nephropathy and retinopathy (p less than 0.05). There were no significant differences in the levels of t-PA, t-PA/PAI-1 ratio and PAI-1 between younger (less than 65 years) and older (65 years or more) subjects, in either the control or diabetic groups.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diet therapy in non-insulin dependent diabetes mellitus (NIDDM)

The main approach in NIDDM therapy is diet. Most patients present insulin resistance characterized by overweight, VLDL increase, minimal increase of LDL, decrease of HDL cholesterol, and hypertension. The overall goals of nutrition therapy are the maintenance of near normal glucose levels, and the achievement of optimal serum lipid levels with adequate calories for maintaining or attaining a reasonable body weight. In presence of obesity and hypertension even a slightly weight loss could achieve an improvement in metabolic control and in hypertension with a better life expectance. General-ly carbohydrate intake would represent the 50-60% of total caloric amount (with preference to those with low glycemic index), and lipids no more than 35% (less than 10% of these 10-15% from monounsaturated fats with less than 300 mg/day of cholesterol). If elevated very low density lipoproteins level is the primary problem, a beneficial approach is 10% of total caloric intake from saturated fats, 10% from polyunsaturated, and 15-20% from monounsaturated fats with less than 200 mg/day of cholesterol and 40% of carbohydrates. A large amount of fructose (20% of calories) may increase LDL levels but sweeteners as saccarine or aspartame are approved and determine a better diet compliance. Daily consumpion of 20-35 g of dietary fibres from food sources is recommended for metabolic control. Protein intake would be of about 10% of total caloric amount especially in presence of diabetic nepropathy. Alcohol would not exceed 30 g/day for men and 20 g/day for women keeping in mild that alcohol may worsen metabolic control, diet compliance, and may be dangerous itself. For people with hypertension a decrease of dietary sodium intake is recommended. Nutritional recommendations are developed to meet treatment goals and desired outcomes. Monitoring metabolic parameters, blood pressure, and body weight is very important to ensure successful outcomes.     

Effect of sulfonylurea agents on pyruvate dehydrogenase activity in circulating lymphocytes from patients with non-insulin-dependent diabetes mellitus (NIDDM)

In circulating lymphocytes from patients with non-insulin-dependent diabetes mellitus (NIDDM) subnormal pyruvate dehydrogenase (PDH) activity returns to normal following patient treatment with sulfonylurea (gliclazide^*, 80 mg twice daily/5 weeks). Moreover, in vitro in cells from diabetic patients exposed to insulin at 50 μU/mL PDH activation also occurs; in cells of controls the same happens for insulin at 5 μU/mL, whereas at 50 μU/mL inhibition takes place. Therefore, the low PDH activity in cells of NIDDM patients might be caused by defective insulin control on the enzyme and its recovery in gliclazide-treated patients by drug-mediated removal of the defect. The validity of the hypothesis was verified in this study where cells of NIDDM patients before and after gliclazide treatment were exposed, in vitro, to insulin at 5 and 50 μU/mL and then tested for PDH activity. In such conditions, the profile of PDH behavior in treated patients was no longer comparable to that in untreated patients but closer to that in euglycemic controls, thus supporting the view that the recovery of PDH activity in NIDDM patients following gliclazide treatment might be the expression of an additional effect that the drug would have in these patients, aimed to renew cell responsiveness to insulin.     

Primary prevention of Type 2 (non-insulin-dependent) diabetes mellitus

Summary Type 2 (non-insulin-dependent) diabetes mellitus is the major form of the disease in all societies. Its public health impact appears to be increasing and the greatest genetic predisposition to the disease is encountered in developing communities. The reduction or elimination of disease in whole populations is a fundamental goal in public health. Whilst several factors are associated with the development of Type 2 diabetes, it is not clear how they cause the disease, if indeed they do, nor whether they act in the same way in all populations. Risk factors may be true determinants of a disease but alternatively they may be associated with its occurrence only by virtue of an innocent relationship with the true causes. Furthermore, known risk factors usually explain only a small proportion of any chronic disease. The role of risk factors in disease causation is therefore of fundamental importance in considering disease prevention. Two alternative strategies for prevention of disease in populations have been proposed. The population strategy seeks to remove the causes of disease in communities as a whole, whilst the high-risk strategy aims to identify subjects at increased risk, and to intervene selectively. The population approach should be tried and carefully evaluated in selected communities at above-average risk of several noncommunicable diseases. However, certain epidemiological features of Type 2 diabetes, including the distributional characteristics of glycaemia and the complications of hyperglycaemia, the clustering of cardiovascular risk factors in the diabetic subpopulation, as well as uncertainties over the causal nature of known risk factors, suggest that a high-risk approach to prevention is also appropriate. Optimal allocation of resources to the two approaches requires a detailed knowledge of the disease process in individual communities.     

Changes in insulin receptor functions of the erythrocyte by treatment of non-insulin-dependent diabetes mellitus (NIDDM) patients with glibenclamide and diet control

Summary The insulin binding of erythrocytes from: (i) fifteen age-matched normal subjects, (ii) ten untreated NIDDM patients and (iii) fifteen treated (glibenclamide + hypocaloric diet) NIDDM patients (all males) has been studied. A significant decrease in specific insulin binding was observed in group (ii) which improved in cases controlled after treatment (group iii). Scatchard analysis of the results suggested that changes in insulin binding were due to alteration in the number of insulin receptors on erythrocytes. The number of insulin receptors/cell was 471 in normals, 160 in diabetics and 282 in treated diabetic subjects. No significant change in the binding affinity was observed in the three groups (1.0×10⁸, 1.2 × 10⁸ and 1.1×10⁸ M⁻¹ in normal subjects, untreated diabetics and treated diabetics, respectively). CDRI Communication No. 3807.     

Concordance for Type 2 (non-insulin-dependent) diabetes mellitus in male twins

Summary Concordance for Type 2 (non-insulin-dependent) diabetes was determined in 250 monozygotic and 264 dizygotic white male twin pairs who participated in the National Heart, Lung, and Blood Institute Twin Study. These twins were born between 1917 and 1927 and were identified from military records without regard to disease status. We examined surviving members of the cohort twice — at mean ages of 47 and 57 years — and obtained 1-h post-load glucose tests and medication histories. Diagnostic criteria for Type 2 diabetes included a glucose value13.9 mmol/l or current use of antidiabetic medication; possible Type 1 (insulin-dependent) diabetic twins were excluded. A strong genetic predisposition to Type 2 diabetes was suggested by 3 lines of evidence from the second examination: (1) 58% of monozygotic co-twins of diabetic twins were themselves diabetic compared with an expected prevalence of 10%; (2) only 1 of 15 originally disease-discordant, monozygotic twin pairs remained discordant for diabetes; and (3) 65% of non-diabetic monozygotic co-twins of diabetic twins had elevated glucose values. Because concordance for diabetes was less than 100% for twins aged 52–65 years and because twins varied in age at onset of disease, non-genetic factors may also influence diabetes development. Among the 19 monozygotic twins pairs discordant for diabetes, diabetic twins did not differ from their non-diabetic co-twins in obesity, diet, alcohol consumption, or education. However, compared with unrelated nondiabetic twins of the same ages, non-diabetic co-twins of diabetic twins gained more weight as adults (p<0.02) and had higher glucose levels (p<0.03).     

Insulin receptor gene polymorphisms in Type 2 (non-insulin-dependent) diabetes mellitus

Summary The insulin receptor has been proposed as a candidate gene for the inherited defect in Type 2 (non-insulin-dependent) diabetes mellitus and we therefore studied three restriction fragment length polymorphic sites, two revealed with the enzyme Sst1 and one by Rsa1, using two insulin receptor cDNA probes in 131 Caucasian Type 2 diabetic patients and 94 control subjects. The frequency of the six alleles studied did not differ significantly between the two groups. However, one allele, a 6.2 kilobase Rsa1 fragment (R+), was found more frequently in those diabetic subjects (n=48) with a positive family history of diabetes (R+frequency=0.48) compared to those diabetic subjects (n=63) with a negative family history (R+frequency=0.34, p< 0.05). These results suggest that this polymorphism may be a linkage marker for the genetic defect in a subgroup of Type 2 diabetic patients with a positive family history.