Nebojsa Lalic

Insulin resistance and hypersecretion in obesity. European Group for the Study of Insulin Resistance (EGIR).

Insulin resistance and insulin hypersecretion are established features of obesity. Their prevalence, however, has only been inferred from plasma insulin concentrations. We measured insulin sensitivity (as the whole-body insulin-mediated glucose uptake) and fasting posthepatic insulin delivery rate (IDR) with the use of the euglycemic insulin clamp technique in a large group of obese subjects in the database of the European Group for the Study of Insulin Resistance (1,146 nondiabetic, normotensive Caucasian men and women aged 18-85 yr, with a body mass index (BMI) ranging from 15 to 55 kg.m-2). Insulin resistance, defined as the lowest decile of insulin sensitivity in the lean subgroup (608 subjects with a mean BMI of 29 kg.m-2). Insulin sensitivity declined linearly with BMI at an age- and sex-adjusted rate of 1.2 micromol.min-1.kg FFM-1 per BMI unit (95% confidence intervals = 1.0-1.4). Insulin hypersecretion, defined as the upper decile of IDR, was significantly (P<0.0001) more prevalent (38%) than insulin resistance in the obese group. In the whole dataset, IDR rose as a function of both BMI and insulin resistance in a nonlinear fashion. Neither the waist circumference nor the waist-to-hip ratio, indices of body fat distribution, was related to insulin sensitivity after adjustment for age, gender, and BMI; both, however, were positively associated (P<0.001) with insulin hypersecretion, particularly in women. In nondiabetic, normotensive obese subjects, the prevalence of insulin resistance is relatively low, and is exceeded by the prevalence of insulin hypersecretion, particularly in women with central obesity. In the obese with preserved insulin sensitivity, risk for diabetes, cardiovascular risk, and response to treatment may be different than in insulin resistant obesity.

Glucose Homeostasis in Huntington Disease: Abnormalities in Insulin Sensitivity and Early-Phase Insulin Secretion

BACKGROUND Patients with Huntington disease (HD) develop diabetes mellitus more often than do matched healthy controls. Recent studies in neurodegenerative diseases suggested that insulin resistance constitutes a metabolic stressor that interacts with a preexisting neurobiological template to induce a given disorder. OBJECTIVE To investigate possible changes in insulin sensitivity and secretion, major determinants of glucose homeostasis, in a group of consecutive normoglycemic patients with HD. DESIGN Metabolic investigations. PARTICIPANTS Twenty-nine untreated, nondiabetic patients with HD and 22 control participants matched by age, sex, and socioeconomic background. MAIN OUTCOME MEASURES Glucose tolerance, assessed by means of the glucose curve during oral glucose challenge; insulin sensitivity, assessed using homeostasis model assessment and minimal model analysis based on frequent sampling of plasma glucose and plasma insulin during the intravenous glucose tolerance test; and insulin secretion, determined by means of the acute insulin response and the insulinogenic index. RESULTS The evaluation of insulin sensitivity using homeostasis model assessment demonstrated higher homeostasis model assessment insulin resistance indices, and a lower sensitivity index when the minimal model approach was used, in patients with HD compared with controls (P = .03 and P = .003, respectively). In the assessment of early-phase insulin secretion, the acute insulin response and the insulinogenic index were lower in patients with HD compared with controls (P = .02). The number of CAG repeats correlated significantly only with acute insulin response (P = .003). CONCLUSIONS Besides impairment in insulin secretion capacity, a simultaneous decrease in insulin sensitivity, with an increase in the insulin resistance level, was found in normoglycemic patients with HD compared with controls. These data imply that progression of the insulin secretion defect in HD may lead to a failure to compensate for insulin resistance.

Parameters of antioxidative defense in type 2 diabetic patients with cardiovascular complications

OBJECTIVE. Diabetes‐associated oxidative stress is a consequence of both increased production of free radicals and reduced capacity of antioxidative defense. Prolonged hyperglycemia is the major factor in the pathogenesis of atherosclerosis in diabetes which can lead to cardiovascular complications. The aim of this study was to test the parameters of antioxidative defense in type 2 diabetic patients. METHODS. A total of 117 type 2 diabetics with and without cardiovascular complications were examined in order to find out the influence of hyperglycemia, type and duration of complications and duration of diabetes on the extent of disorder of antioxidative parameter values: superoxide dismutase (SOD), glutathione peroxidase (GSH‐Px), glutathione reductase (GR) and total antioxidant status (TAS). RESULTS. Compared to healthy control subjects, type 2 diabetic patients with cardiovascular complications (CVC) had significantly lower SOD (P<0.0001), GSH‐Px (P<0.0001), GR ( P = 0.0002) and TAS values (P<0.0001). In type 2 diabetic subjects with CVC, males had significantly lower SOD (778.7±103.2 U/gHb, P<0.01) and GR activities (52.2±8.9 U/L, P<0.001) compared to females (839.3±94.9 U/gHb; 58.5±9.1 U/L). Significant and positive correlation was found between glucose levels and SOD (r = 0.375 for P<0.05) and GSH‐Px (r = 0.384, P<0.05 ) activity in the group of complications‐free diabetics, while significant negative correlation between glucose and GSH‐Px values (r = −0.382, P<0.05) was found in the group of type 2 diabetics with coronary artery disease (CAD) and hypertension (HTA) and with CAD and acute myocardial infarction (AMI) (r = −0.860 P<0.05), and highly negative correlation between glucose and SOD levels (r = −0.590, P<0.05) in the group of diabetic subjects with CAD, AMI and HTA. Likewise, there was highly significant negative correlation of SOD (r = −0.949, P<0.05) and TAS (r = −0.393 for P = 0.038) with duration of diabetes in the group of diabetics with CAD and HTA. CONCLUSION. Our results confirm the hypothesis that there is reduced antioxidative defense in type 2 diabetics with prominent cardiovascular complications, which negatively correlates with glucose concentrations and duration of diabetes and cardiovascular complications.

Relation of the Mediterranean diet with the incidence of gestational diabetes

Background/objectives:Some studies document relationships of the incidence of gestational diabetes mellitus (GDM) with individual components of the diet, but studies exploring relationships with patterns of eating are lacking. This observational study aimed to explore a possible relationship between the incidence of GDM and the Mediterranean diet (MedDiet) pattern of eating.Subjects/methods:In 10 Mediterranean countries, 1076 consecutive pregnant women underwent a 75-g OGTT at the 24th–32nd week of gestation, interpreted both by the ADA_2010 and the International Association of the Diabetes and Pregnancy Study Groups (IADPSG)_2012 criteria. The dietary habits were assessed by a previously validated questionnaire and a Mediterranean Diet Index (MDI) was computed, reflecting the degree of adherence to the MedDiet pattern of eating: a higher MDI denoting better adherence.Results:After adjustment for age, BMI, diabetes in the family, weight gain and energy intake, subjects with GDM, by either criterion, had lower MDI (ADA_2010, 5.8 vs 6.3, P=0.028; IADPSG_2012, 5.9 vs 6.4, P<0.001). Moreover, the incidence of GDM was lower in subjects with better adherence to the MedDiet (higher tertile of MDI distribution), 8.0% vs 12.3%, OR=0.618, P=0.030 by ADA_2010 and 24.3% vs 32.8%, OR=0.655, P=0.004 by IADPSG_2012 criteria. In subjects without GDM, MDI was negatively correlated with both fasting plasma glucose and AUC glucose, P<0.001 for both.Conclusions:Adherence to a MedDiet pattern of eating is associated with lower incidence of GDM and better degree of glucose tolerance, even in women without GDM. The possibility to use MedDiet for the prevention of GDM deserves further testing with intervention studies.

Routine Sensor-Augmented Pump Therapy in Type 1 Diabetes: The INTERPRET Study

BACKGROUND Sensor-augmented pump (SAP) therapy can improve glycemic control, compared with multiple daily insulin injections or with insulin pump therapy alone, without increasing the risk of hypoglycemia. SUBJECTS AND METHODS A 12-month observational study in patients with type 1 diabetes treated with continuous subcutaneous insulin infusion (CSII), upon the introduction of continuous glucose monitoring (CGM), was conducted in 15 countries (in Europe and in Israel) to document the real-life use of SAP and assess which variables are associated with improvement in type 1 diabetes management. RESULTS Data from 263 patients (38% male; mean age, 28.0 ± 15.7 years [range, 1-69 years]; body mass index, 23.3 ± 4.9 kg/m(2); diabetes duration, 13.9 ± 10.7 years; CSII duration, 2.6 ± 3 years) were collected. Baseline mean glycated hemoglobin A1c (HbA1c) was 8.1 ± 1.4%; 82% had suboptimal HbA1c (≥ 7%). The average sensor use for 12 months was 30% (range, 0-94%), and sensor use decreased with time (first 3 months, 37%; last 3 months, 27%). Factors associated with improvement in HbA1c after 12 months in patients with baseline HbA1c ≥ 7% were high baseline HbA1c (P<0.001), older age group (P<0.001), and more frequent sensor use (P = 0.047). Significantly less hospitalization, increased treatment satisfaction, and reduced fear of hypoglycemia were reported after 12 months of SAP. CONCLUSIONS This is the largest and longest multicenter prospective observational study providing real-life data on SAP. These results are consistent with those of controlled trials showing the effectiveness of CGM in pump users.

Rates and predictors of hypoglycaemia in 27 585 people from 24 countries with insulin-treated type 1 and type 2 diabetes: the global HAT study.

To determine the global extent of hypoglycaemia experienced by patients with diabetes using insulin, as there is a lack of data on the prevalence of hypoglycaemia in developed and developing countries.

Relationship between Obesity, Adipocytokines and Inflammatory Markers in Type 2 Diabetes: Relevance for Cardiovascular Risk Prevention

This study aimed to analyse the impact of obesity in type 2 diabetes (T2D) on adipocytokines (adiponectin, leptin and resistin) and inflammatory markers (TNF-α, IL-6 and hsCRP) as cardiovascular risk factors. A cross-sectional study comparing the basal levels of adipocytokines and inflammatory markers was done in 18 obese (BMI ≥ 30 kg/m2) (group A), 21 overweight (25 kg/m2 ≤ BMI < 30 kg/m2) (group B), 25 non-obese T2D patients (group C) and 15 non-obese controls (group D). The lowest levels of adiponectin and the highest levels of leptin, resistin, TNF-α, IL-6 and hsCRP were found in group A. Adiponectin levels were significantly lower, and resistin, TNF-α, and hsCRP levels were elevated in group C vs. D. However, leptin and IL-6 levels differed significantly between groups A and B, but not between groups C and D. Moreover, we found a significant negative correlation between adiponectin and TNF-α, but not with other markers, which was independent of the presence of obesity. In contrast, leptin and resistin correlated with the inflammatory markers, and this correlation was obesity-dependent. Our results suggest that obesity influences cardiovascular risk primarily through changes in leptin and resistin and less efficiently at the level of adiponectin.

Influence of Hyperinsulinemia and Insulin Resistance on In Vivo β-Cell Function: Their Role in Human β-Cell Dysfunction

OBJECTIVE Recent work has shown that insulin stimulates its own secretion in insulin-sensitive humans, suggesting that insulin resistance in the β-cell could cause β-cell dysfunction. We have tested whether insulin exposure and insulin sensitivity modulate β-cell function in subjects with normal glucose tolerance (NGT) and whether they contribute to dysglycemia in impaired glucose regulation (IGR). RESEARCH DESIGN AND METHODS Insulin sensitivity (by euglycemic clamp), insulin-induced secretory response at isoglycemia (IISR) (as C-peptide percent change from basal during the clamp), glucose-induced secretory response (GISR) to an intravenous glucose bolus, and β-cell glucose sensitivity (β-GS) (by oral glucose tolerance test [OGTT] modeling) were measured in 1,151 NGT and 163 IGR subjects from the RISC (Relationship between Insulin Sensitivity and Cardiovascular Disease) study. RESULTS In NGT, IISR was related to both insulin sensitivity and antecedent insulin exposure; GISR was related to insulin exposure. IISR was positively, if weakly, related to β-GS (r= 0.16, P < 0.0001). Both IISR (−23 [39] vs. −9 [2]%, median [interquartile range], P < 0.03) and β-GS (69 [47] vs. 118 [83] pmol ⋅ min–1 ⋅ m–2 ⋅ mmol–1 ⋅ L, P < 0.0001) were decreased in IGR compared with NGT. Insulin sensitivity and β-GS were the major determinants of mean OGTT glucose in both NGT and IGR, with a minor role for IISR. In a multivariate logistic model, IGR was predicted by β-GS (odds ratio 4.84 [95% CI 2.89–8.09]) and insulin sensitivity (3.06 [2.19–4.27]) but not by IISR (1.11 [0.77–1.61]). CONCLUSIONS Pre-exposure to physiological hyperinsulinemia stimulates insulin secretion to a degree that depends on insulin sensitivity. However, this phenomenon has limited impact on β-cell dysfunction and dysglycemia.

Hypertension in obese type 2 diabetes patients is associated with increases in insulin resistance and IL-6 cytokine levels: potential targets for an efficient preventive intervention.

Increased body weight as well as type 2 diabetes (T2D) are found to be associated with increased incidence of hypertension, although the mechanisms facilitating hypertension in T2D or nondiabetic individuals are not clear. Therefore, in this study we compared the levels of insulin resistance (IR:OGIS), plasma insulin (PI:RIA) levels, and pro-inflammatory cytokines (IL-6 and TNF-α: ELISA), being risk factors previously found to be associated with hypertension, in T2D patients showing increased body weight (obese and overweight, BMI ≥ 25 kg/m2) with hypertension (group A, N = 30), or without hypertension (group B, N = 30), and in nonobese (BMI < 25 kg/m2), normotensive controls (group C, N = 15). We found that OGIS index was the lowest (A: 267 ± 35.42 vs. B: 342.89 ± 32.0, p < 0.01) and PI levels were the highest (A: 31.05 ± 8.24 vs. B: 17.23 ± 3.23, p < 0.01) in group A. In addition, IL-6 levels were higher in group A (A: 15.46 ± 5.15 vs. B: 11.77 ± 6.09; p < 0.05) while there was no difference in TNF-α levels. Our results have shown that appearance of hypertension in T2D patients with increased body weight was dependent on further increase in IR which was associated with the rise in pro-inflammatory IL-6 cytokine. The results imply that lifestyle intervention aimed to decrease IR might be beneficial in reducing the risk for hypertension in those T2D individuals.

Metabolic characteristics of prehypertension: role of classification criteria and gender.

Objective We tested whether men and women in the European Society of Hypertension (ESH) high normal and normal blood pressure (BP) categories, all included in the the Seventh Joint National Committee (JNC 7) prehypertension group, share similar metabolic characteristics and whether they differ from men and women with optimal BP (<120/80 mmHg). Methods BP (multiple measurements with a standardized automatic device), insulin sensitivity (euglycaemic clamp), oral glucose tolerance test (OGTT), carotid intima–media-thickness (IMT, echo), family history (questionnaire), physical activity (accelerometer), and anthropometrics (bioimpedance) were evaluated in the 1384 healthy European individuals ranging from 30–60 years participating in the multicentre study Relationship between Insulin Sensitivity and Cardiovascular disease (RISC). Results BMI and waist-to-hip ratio were higher (both P < 0.05 adjusted for age and recruiting centre) in men and women with high normal (but not normal) BP with respect to optimal BP. Similarly, in women (after adjustment for study centre, age, physical activity, and waist), serum triglycerides and carotid IMT were higher in those with high normal (but not normal) BP; moreover, in this group there was a higher prevalence of glucose-intolerance (21.8 versus 9.7%, P = 0.02) and insulin sensitivity tended to be lower (P = 0.07). Insulin sensitivity and diastolic blood pressure were weakly related variables displaying a nonlinear association with a threshold below the normal BP values and no interaction with family history of hypertension. Conclusion The JNC 7 category prehypertension identifies a dishomogeneous group of individuals whereas the ESH classification, particularly in women, was more accurate in identifying both the predisease and the healthy phenotype. Insulin resistance is not a major characteristic of the condition of prehypertension.