Ljiljana Lukic

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.

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.

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.

Altered Daytime Fluctuation Pattern of Plasminogen Activator Inhibitor 1 in Type 2 Diabetes Patients with Coronary Artery Disease: A Strong Association with Persistently Elevated Plasma Insulin, Increased Insulin Resistance, and Abdominal Obesity

This study was aimed at investigating daily fluctuation of PAI-1 levels in relation to insulin resistance (IR) and daily profile of plasma insulin and glucose levels in 26 type 2 diabetic (T2D) patients with coronary artery disease (CAD) (group A), 10 T2D patients without CAD (group B), 12 nondiabetics with CAD (group C), and 12 healthy controls (group D). The percentage of PAI-1 decrease was lower in group A versus group B (4.4 ± 2.7 versus 35.0 ± 5.4%; P < 0.05) and in C versus D (14.0 ± 5.8 versus 44.7 ± 3.1%; P < 0.001). HOMA-IR was higher in group A versus group B (P < 0.05) and in C versus D (P < 0.01). Simultaneously, AUCs of PAI-1 and insulin were higher in group A versus group B (P < 0.05) and in C versus D (P < 0.01), while AUC of glucose did not differ between groups. In multiple regression analysis waist-to-hip ratio and AUC of insulin were independent determinants of decrease in PAI-1. The altered diurnal fluctuation of PAI-1, especially in T2D with CAD, might be strongly influenced by a prolonged exposure to hyperinsulinemia in the settings of increased IR and abdominal obesity, facilitating altogether an accelerated atherosclerosis.

Decreased Insulin Sensitivity and Impaired Fibrinolytic Activity in Type 2 Diabetes Patients and Nondiabetics with Ischemic Stroke

We analyzed (a) insulin sensitivity (IS), (b) plasma insulin (PI), and (c) plasminogen activator inhibitor-1 (PAI-1) in type 2 diabetes (T2D) patients with (group A) and without (group B) atherothrombotic ischemic stroke (ATIS), nondiabetics with ATIS (group C), and healthy controls (group D). IS was determined by minimal model (Si). Si was lower in A versus B (1.18 ± 0.67 versus 2.82 ± 0.61 min−1/mU/L × 104; P < 0.001) and in C versus D (3.18 ± 0.93 versus 6.13 ± 1.69 min−1/mU/L × 104; P < 0.001). PI and PAI-1 were higher in A versus B (PI: 19.61 ± 4.08 versus 14.91 ± 1.66 mU/L; P < 0.001, PAI-1: 7.75 ± 1.04 versus 4.57 ± 0.72 mU/L; P < 0.001) and in C versus D (PI: 15.14 ± 2.20 versus 7.58 ± 2.05 mU/L; P < 0.001, PAI-1: 4.78 ± 0.98 versus 3.49 ± 1.04 mU/L; P < 0.001). Si correlated with PAI-1 in T2D patients and nondiabetics, albeit stronger in T2D. Binary logistic regression identified insulin, PAI-1, and Si as independent predictors for ATIS in T2D patients and nondiabetics. The results imply that insulin resistance and fasting hyperinsulinemia might exert their atherogenic impact through the impaired fibrinolysis.

High Prevalence of Risk Factors for Chronic Kidney Disease in Balkan Endemic Nephropathy Foci

Background/Aims: The aim of this study was to find out the prevalence of the most frequent risk factors for chronic kidney disease (CKD) and the prevalence of urinary abnormalities in adult inhabitants of three Balkan endemic nephropathy (BEN) villages near Bijeljina, Bosnia and Herzegovina. Methods: The survey consisted of an interview, blood pressure measurement, and urine dipstick test for proteinuria, hematuria, and glycosuria. Results: The study involved 1625 (739 males, aged 51 ± 16 years) subjects: 319 (19.6%) with positive family history for BEN, 585 (36%) with hypertension, 604 (37.2%) above 60 years, 146 (9%) with diabetes, and 566 (34.8%) with none of these risk factors. Proteinuria was present in 6.2–7.1% of the subjects with risk factors for CKD but in 3.4% of those without risk factors. Systolic blood pressure and BEN in brother/sister were found to be significant variables associated with proteinuria, but female gender and history of kidney disease with hematuria. Conclusion: In addition to a family burden for BEN, other risk factors for CKD were highly prevalent in BEN villages of the Bijeljina municipality. The frequency of proteinuria was higher in the at-risk group than in the group without risk factors and increased with the number of risk factors.

Type 2 diabetic patients with ischemic stroke: decreased insulin sensitivity and decreases in antioxidant enzyme activity are related to different stroke subtypes.

We analyzed (a) insulin sensitivity (IS) and (b) glutathione peroxidase (GSH-Px), glutathione reductase (GR), and superoxide dismutase (SOD) antioxidant enzyme activity in type 2 diabetic (T2D) patients with atherothrombotic infarction (ATI) (group A), lacunar infarction (LI) (B), or without stroke (C) and in nondiabetics with ATI (D), LI (E), or without stroke (F). ATI and LI were confirmed by brain imaging IS levels were determined by minimal model (Si index), and the enzyme activity by spectrophotometry. In T2D patients, Si was lower in A and B versus C (1.14 ± 0.58, 1.00 ± 0.26 versus 3.14 ± 0.62 min−1/mU/l × 104, P < 0.001) and in nondiabetics in D and E versus F (3.38 ± 0.77, 3.03 ± 0.72 versus 6.03 ± 1.69 min−1/mU/l × 104, P < 0.001). Also, GSH-Px and GR activities were lower in A and B versus C (GSH-Px: 21.96 ± 3.56, 22.51 ± 1.23 versus 25.12 ± 1.67; GR: 44.37 ± 3.58, 43.50 ± 2.39 versus 48.58 ± 3.67 U/gHb; P < 0.001) and in D and E versus F (GSH-Px: 24.75 ± 3.02, 25.57 ± 1.92 versus 28.56 ± 3.91; GR: 48.27 ± 6.81, 49.17 ± 6.24 versus 53.67 ± 3.96 U/gHb; P < 0.001). Decreases in Si and GR were significantly related to both ATI and LI in T2D. Our results showed that decreased IS and impaired antioxidant enzymes activity influence ischemic stroke subtypes in T2D. The influence of insulin resistance might be exerted on the level of glutathione-dependent antioxidant enzymes.

Increased left ventricular mass index is present in patients with type 2 diabetes without ischemic heart disease

Left ventricular mass index (LVMI) increase has been described in hypertension (HTN), but less is known about its association with type 2 diabetes (T2DM). As these conditions frequently co-exist, we investigated the association of T2DM, HTN and both with echocardiographic parameters, and hypothesized that patients with both had highest LVMI, followed by patients with only T2DM or HTN. Study population included 101 T2DM patients, 62 patients with HTN and no T2DM, and 76 patients with T2DM and HTN, excluded for ischemic heart disease. Demographic and clinical data, biochemical measurements, stress echocardiography, transthoracic 2D Doppler and tissue Doppler echocardiography were performed. Multivariable logistic regression was used to determine the independent association with T2DM. Linear regression models and Pearson’s correlation were used to assess the correlations between LVMI and other parameters. Patients with only T2DM had significantly greater LVMI (84.9 ± 20.3 g/m2) compared to patients with T2DM and HTN (77.9 ± 16 g/m2) and only HTN (69.8 ± 12.4 g/m2). In multivariate logistic regression analysis, T2DM was associated with LVMI (OR 1.033, 95%CI 1.003–1.065, p = 0.029). A positive correlation of LVMI was found with fasting glucose (p < 0.001) and HbA1c (p = 0.0003). Increased LVMI could be a potential, pre-symptomatic marker of myocardial structural change in T2DM.

OP3: Oxidized LDL as residual lipid risk marker in type 2 diabetes

Background and aims Previous studies have revealed that the excess of cardiovascular events observed in patients with type 2 diabetes (T2D) and adequate control of low-density lipoprotein cholesterol (LDL) has been explained through the residual lipid risk. The atherogenic potential of diabetes could be associated with the modified proteins as the result of glycation and oxidation. The role of oxidized LDL (oxLDL) as a residual lipid risk marker is still unclarified. The aim of our study was to analyze the levels of oxLDL and their relationship with other standard lipid atherogenic risk factors as well as with insulin resistance (IR) in: T2D patients with coronary artery disease (CAD) (Group A, N=50), T2D patients without CAD (group B, N=45), and nondiabetic patients with CAD (group C, N=50). Material and Methods Patients were aged 40–70 years, matched by gender, duration of diabetes, smoking habit and hypertension. CAD was defined as the presence of any of the following: a) angina, b) myocardial infarction or c) positive angiography. In each patient, oxLDL levels were measured by ELISA methods (Mercodia), glycemic control by the glycated hemoglobin levels (HbA1c, measured by immuno-inhibition). Total cholesterol (TC), HDL and LDL cholesterol and triglycerides (Tg) were determined by enzymatic methods. IR was calculated using homeostatic model assessment insulin resistance (HOMA-IR) index. Results We found the highest levels of oxLDL in group A, being significantly higher than in groups B and C (A: 112.2±22.0, B: 95.9±10.2, C: 83.9±8. A vs B p Conclusion Our results have demonstrated that in patients with T2D and CAD increased oxLDL levels could be good residual lipid risk marker. Atherogenic potential in T2D is associated predominantly with the increased oxLDL, higher IR and impairments in triglycerides metabolism but not with the levels of lipoproteins. Also, the results imply that in T2D patients LDL oxidation is significantly influenced by the impairments in glucose control.

High Risk First Degree Relatives of Type 1 Diabetics: An Association with Increases in CXCR3+ T Memory Cells Reflecting an Enhanced Activity of Th1 Autoimmune Response

We analyzed the level of (a) CXCR3+ (Th1) and CCR4+ (Th2) T memory cells (b) interferon-γ inducible chemokine (IP-10)(Th1) and thymus and activation-regulated chemokine (TARC)(Th2), in 51 first degree relatives (FDRs) of type 1 diabetics (T1D) (17 high risk FDRs (GADA+, IA-2+) and 34 low risk FDRs (GADA−, IA-2−)), 24 recent-onset T1D (R-T1D), and 18 healthy subjects. T memory subsets were analyzed by using four-color immunofluorescence staining and flowcytometry. IP-10 and TARC were determined by ELISA. High risk FDRs showed higher levels of CXCR3+ and lower level of CCR4+ T memory cells compared to low risk FDRs (64.98 ± 5.19 versus 42.13 ± 11.11; 29.46 ± 2.83 versus 41.90 ± 8.58%, resp., P < 0.001). Simultaneously, both IP-10 and TARC levels were increased in high risk versus low risk FDRs (160.12 ± 73.40 versus 105.39 ± 71.30; 438.83 ± 120.62 versus 312.04 ± 151.14 pg/mL, P < 0.05). Binary logistic regression analysis identified the level of CXCR3+ T memory cells as predictors for high risk FDRs, together with high levels of IP-10. The results imply that, in FDRs, the risk for T1D might be strongly influenced by enhanced activity of Th1 and diminished activity of Th2 autoimmune response.