Esperanza Martínez-Abundis

The Product of Triglycerides and Glucose, a Simple Measure of Insulin Sensitivity. Comparison with the Euglycemic-Hyperinsulinemic Clamp

CONTEXT To meet the worldwide challenge of emerging diabetes, accessible and inexpensive tests to identify insulin resistance are needed. OBJECTIVE To evaluate the sensitivity and specificity of the product of fasting, we compared the triglycerides and glucose (TyG) index, a simple measure of insulin resistance, with the euglycemic-hyperinsulinemic clamp test. DESIGN AND SETTING We conducted a cross-sectional study of the general population and outpatients of the Internal Medicine Department at the Medical Unit of High Specialty of the Specialty Hospital at the West National Medical Center in Guadalajara, Mexico. PATIENTS Eleven nonobese healthy subjects, 34 obese normal glucose tolerance individuals, 22 subjects with prediabetes, and 32 diabetic patients participated in the study. INTERVENTION We performed a euglycemic-hyperinsulinemic clamp test. MAIN OUTCOME MEASURES Sensitivity and specificity of the TyG index [Ln(fasting triglycerides) (mg/dl) x fasting glucose (mg/dl)/2] were measured, as well as the area under the curve of the receiver operating characteristic scatter plot and the correlation between the TyG index and the total glucose metabolism (M) rates. RESULTS Pearsons correlation coefficient between the TyG index and M rates was -0.681 (P < 0.005). Correlation between the TyG index and M rates was similar between men (-0.740) and women (-0.730), nonobese (-0.705) and obese (-0.710), and nondiabetic (-0.670) and diabetic (-0.690) individuals. The best value of the TyG index for diagnosis of insulin resistance was 4.68, which showed the highest sensitivity (96.5%) and specificity (85.0%; area under the curve + 0.858). CONCLUSIONS The TyG index has high sensitivity and specificity, suggesting that it could be useful for identification of subjects with decreased insulin sensitivity.

Serum leptin levels in women with systemic lupus erythematosus

Abstract The purpose of this study was to evaluate serum leptin levels in systemic lupus erythematosus (SLE). Forty-one women with SLE were compared with 23 healthy women of similar age and body mass index (BMI). Clinical characteristics and Mexican systemic lupus erythematosus disease activity index (Mex-SLEDAI) score were assessed. Serum leptin levels (ng/dl) were measured by enzyme-linked immunosorbent assay (ELISA). Comparisons of leptin levels were made with the Mann-Whitney U-test. In a multiple regression analysis, those factors that could influence the leptin levels were adjusted. Patients with SLE had higher leptin levels than the control group (SLE median 31 vs control median 15, P=0.023). After adjusting by other variables, the serum leptin levels remained higher in SLE than in controls (P=0.02). Patients with SLE had no association between leptin levels and Mex-SLEDAI score, age, duration of disease, or prednisone doses. Those with SLE had higher leptin levels than controls. Further longitudinal studies are required to evaluate the role of this hormone in the exacerbations of SLE.

Effect of Resveratrol Administration on Metabolic Syndrome, Insulin Sensitivity, and Insulin Secretion

BACKGROUND The aim of this study was to evaluate the effect of berberine administration on metabolic syndrome, insulin sensitivity, and insulin secretion. METHODS A randomized, double-blind, placebo-controlled clinical trial was carried out in 24 patients with a diagnosis of metabolic syndrome. Glucose and insulin levels after a dextrose load were measured. Triglycerides and high-density lipoprotein cholesterol concentrations at baseline were also measured. Twelve patients received berberine hydrochloride (500 mg) three times daily before meals for 3 months. The remaining 12 patients received placebo. Area under the curve (AUC) of glucose and insulin, total insulin secretion, first-phase of insulin secretion, and insulin sensitivity were assessed. RESULTS After berberine administration, patients had a remission of 36% (P=0.037) in the presence of metabolic syndrome and a significant decrease in waist circumference in females (106±4 vs. 103±3 cm, P<0.05), systolic blood pressure (SBP) (123±7 vs. 115±9 mmHg, P<0.01), triglycerides (2.4±0.7 vs. 1.4±0.5 mmol/L, P<0.01), area under the curve (AUC) of glucose (1182.1±253.6 vs. 1069.5±172.4 mmol/l, P<0.05), AUC of insulin (92,056±72,148 vs. 67,407±46,441 pmol/L, P<0.01), and insulinogenic index (0.78±0.69 vs. 0.62±0.46, P<0.05), as well as an increase in the Matsuda index (2.1±1.0 vs. 3.1±1.6, P<0.01). CONCLUSIONS Administration of berberine leads to remission of metabolic syndrome and decreases in waist circumference, SBP, triglycerides, and total insulin secretion, with an increase in insulin sensitivity.

Efecto de la administración oral de inulina sobre el perfil de lípidos y la sensibilidad a la insulina en individuos con obesidad y dislipidemia

Background: Inulin is a non absorbable polysaccharide with prebiotic effects, whose influence on blood lipids or insulin sensitivity is not well known. Aim: To assess the effect of oral administration of inulin on lipid profile and insulin sensitivity in dyslipidemic obese subjects. Material and Methods: A clinical trial, double blind, randomized with placebo was carried out in 12 obese, hypertrygliceridemic and hypercholesterolemic subjects between 19 and 32 years old. The subjects were randomized to receive 7 g/day of inulin or placebo in the morning, during 4 weeks. Biochemical and metabolic profiles and euglycemic-hyperinsulinemic clamp technique for assessing insulin sensitivity, before and after pharmacological intervention were performed. Results: After inulin administration, there was a significant reduction of total cholesterol (248.7±30.5 and 194.3±39.8 mg/dL; p=0.028), low density lipoprotein (LDL), cholesterol (136.0±27.8 and 113.0±36.2 mg/dL; p= 0.028), very low density lipoproteins (VLDL) (45.9±18.5 and 31.6±7.2 mg/dL; p=0.046) and trygliceride concentrations (235.5±85.9 and 171.1±37.9 mg/dL; p=0.046). No effect of inulin on insulin sensitivity was observed. Conclusions: The oral inulin administration reduced total cholesterol, LDL cholesterol, VLDL and trygliceride levels in dyslipidemic and obese subjects, without modifications in the insulin sensitivity. (Rev Med Chile 2003; 131: 597-604)

Prediabetes and its relationship with obesity in Mexican adults: The Mexican Diabetes Prevention (MexDiab) Study.

BACKGROUND Epidemiological data on impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) based on a representative Mexican sample are not available; thus, the objectives of this study were to determine the prevalence and distribution of IFG and IGT, and to establish its relationship with obesity in Mexican adults. METHODS We performed a cross-sectional population-based study on a representative sample of Mexican adults aged 30 to 65 years. Anthropometric measurements of obesity that included waist circumference (WC) and total body fat percentage were collected and the body mass index calculated. All subjects also underwent an oral glucose tolerance test. Diagnosis of glucose metabolism disorders was based on criteria of the American Diabetes Association. RESULTS Prevalence of IFG, IGT, and IFG+IGT was 24.6%, 8.3%, and 10.3%, respectively. The age-adjusted prevalence of IFG (49.5% and 50.5%), IGT (49.1% and 50.9%), and IFG+IGT (57.3% and 42.7%) was similar in men and women. Prevalence of obesity was 45.9% with predominance in women (48.8% versus 42.1%, P = 0.01). A total of 394 (31.0%) individuals were overweight. Among the 550 prediabetic normal weight subjects, 70 (22.4%), 15 (14.2%), and 7 (5.3%) had IFG, IGT, or IFG+IGT. The odds ratio (OR) between WC and IFG (OR 3.1, CI(95%) 1.4-9.7), IGT (OR 3.2, CI(95%) 1.2-9.1), and IFG+IGT (OR 2.8, CI(95%) 1.3-8.2) was higher than the OR of other measurements of obesity. CONCLUSIONS Prevalence of prediabetes in the Mexican adult population is high. WC is the measure of obesity more strongly associated with metabolic glucose disorders. A high proportion of subjects with normal weight exhibit prediabetes.

Effect of Diacerein on Insulin Secretion and Metabolic Control in Drug-Naïve Patients With Type 2 Diabetes: A randomized clinical trial

OBJECTIVE To assess the effect of diacerein on insulin secretion and metabolic control in drug-naïve patients with type 2 diabetes. RESEARCH DESIGN AND METHODS A randomized, double-blind, placebo-controlled clinical trial was carried out in 40 drug-naïve adult patients with type 2 diabetes. A metabolic profile including interleukin (IL)-1β, tumor necrosis factor-α, IL-6, and fasting insulin levels was carried out before the intervention and 2 months afterward. A hyperglycemic-hyperinsulinemic clamp technique was performed to assess the phases of insulin secretion and insulin sensitivity. After randomization, 20 patients received diacerein (50 mg once daily) for the first 15 days and twice daily for 45 additional days. The remaining patients received placebo. Intra- and intergroup differences were calculated by Wilcoxon signed rank and Mann-Whitney U tests. RESULTS There were significant increases in first (102 ± 63 vs. 130 ± 75 pmol/L; P < 0.01), late (219 ± 111 vs. 280 ± 135 pmol/L; P < 0.01), and total insulin (178 ± 91 vs. 216 ± 99 pmol/L; P < 0.01) secretions without changes in insulin sensitivity after diacerein administration. There were significant decreases in fasting glucose (7.9 ± 1.4 vs. 6.8 ± 1.0 mmol/L; P < 0.01) and in A1C levels (8.3 ± 1.0 vs. 7.0 ± 0.8%; P < 0.001) after diacerein administration. There were no significant changes after placebo administration in the above-mentioned evaluations. CONCLUSIONS Insulin secretion increased and metabolic control improved after diacerein administration in drug-naïve patients with type 2 diabetes.

Effect of Pomegranate Juice on Insulin Secretion and Sensitivity in Patients with Obesity

Aim: To evaluate the effect of pomegranate juice on insulin secretion and sensitivity in patients with obesity. Methods: A randomized, double-blind, placebo-controlled clinical trial was carried out in 20 obese, adult volunteer subjects. After random allocation of the intervention, 10 patients received 120 ml of pomegranate juice or placebo while in a fasted state for 1 month. Glucose, uric acid, creatinine, lipid profile, and insulin were measured at baseline, and glucose and insulin were also measured at 30, 60, 90, and 120 min. The area under the curve of glucose and insulin, total insulin secretion, and insulin sensitivity was calculated. Results: There was a significant increase in weight, body mass index, and fat mass in the placebo group after the intervention. Insulin secretion and insulin sensitivity were not modified with administration of pomegranate juice. There was a significant difference in changes from baseline in fat mass between groups (1.1 ± 1.1% vs. –1.4 ± 3.0%, p = 0.010; placebo and pomegranate groups, respectively). Conclusion: Pomegranate juice administration for 1 month did not modify insulin secretion and sensitivity in patients with obesity; however, the natural evolution to increased weight and adiposity was halted.

Cardiovascular Risk Factors and Acculturation in Yaquis and Tepehuanos Indians from Mexico

BACKGROUND Cardiovascular (CV) risk factors are influenced by behavioral, cultural, and social factors, suggesting that acculturation plays a significant role in the emergency and growth of chronic disease. The objective of this study was to determine the relation between CV risk factors and the main components of acculturation, in Yaquis and Tepehuanos Indians from Mexico. METHODS This was a cross-sectional population-based study in Yaquis and Tepehuanos communities from the Yaqui Valley in Sonora and the Sierra Madre Occidental Mountains in Durango, in northwest Mexico. Acculturation status is different in both ethnic groups, with Tepehuanos living in small and remote communities retaining their traditional lifestyle and Yaquis living in well-communicated communities that have assumed Westernized lifestyles. RESULTS A total of 278 indigenous (120 Tepehuanos and 158 Yaquis) were randomly enrolled. Prevalence of obesity (48.1 and 6.7%, p <0.001), diabetes (18.3 and 0.83%, p <0.001), hypertriglyceridemia (43.0 and 15.0%, p <0.001), alcohol consumption (46.8 and 26.6%, p >0.001), and smoking (29.7 and 15.0%, p = 0.006) were significantly higher in Yaquis Indians. High blood pressure (6.3 and 3.3%, p = 0.40) and low HDL-cholesterol (42.4 and 34.2%, p = 0.22) were similar between Yaquis and Tepehuanos. Multivariate regression analysis adjusted by sex and age showed a significant association between calorie intake from saturated fat, but not other nutrients of customary diet, with hyperglycemia (OR 7.4, 95% CI 2.6-20.1), hypertriglyceridemia (OR 3.1, 95% CI 1.5-6.3), and obesity (OR 3.4, 95% CI 1.6-10.1). CONCLUSIONS Among the components of acculturation, intake of saturated fat is the most strongly associated with the development of CV risk factors.

Effect of Vanadium on Insulin Sensitivity in Patients with Impaired Glucose Tolerance

Background/Aim: Impaired glucose tolerance (IGT) is considered a risk factor for developing type 2 diabetes mellitus (T2DM) and is associated with insulin resistance. Vanadium seems to block protein tyrosine phosphatase with the consequent increment in insulin sensitivity (INS) in T2DM patients, but this effect has not been studied in IGT patients. The aim of this study was to evaluate the effect of vanadium on INS in IGT patients. Methods: A randomized, double-blind, placebo-controlled clinical trial was carried out in 14 overweight/obese patients with IGT. Intervention consisted of vanadyl sulfate (VS, 50 mg p.o. twice daily) or placebo for 4 weeks. Before and after the intervention, a metabolic profile was performed and INS was assessed using the euglycemic-hyperinsulinemic clamp technique. Mann-Whitney U and Wilcoxon rank tests were used for statistical analyses. Results: There were no significant differences in basal characteristics between groups. VS did not affect INS [2.7 ± 0.8 vs. 2.9 ± 0.9 mg/(kg/min), p = 0.735] but increased triglyceride levels (1.35 ± 0.61 vs. 1.70 ± 0.46 mmol/l, p = 0.018). Conclusions: VS administration in IGT patients increased triglyceride concentrations without changes in INS.

[Effect of oral zinc administration on insulin sensitivity, leptin and androgens in obese males].

BACKGROUND Zinc is important for insulin synthesis, storage and secretion. When zinc concentration decrease, there is a concomitant reduction in insulin secretion and peripheral insulin sensitivity. AIM To assess the effects of zinc sulfate on insulin sensitivity, leptin and androgens in obese individuals. MATERIAL AND METHODS A randomized, double-blind, placebo-controlled clinical trial was performed in 14 obese volunteers between 21 and 30 years old, with body mass index (BMI) (3) 27 kg/m2. During one month, seven subjects received 100 mg/day of zinc sulfate orally (ZnG) and the other seven received placebo, as control group (CG). At baseline and after the intervention, insulin sensitivity was measured using a euglycemic-hyperinsulinemic clamp technique. Blood glucose, serum lipids, zinc, androgens and leptin were also measured in a fasting blood sample. RESULTS After the intervention, a rise in zinc concentrations from 11.8 to 16.9 umol/L; p=0.001 and in leptin levels from 15.2 to 27.7 ng/mL; p=0.029, was observed in the ZnG. No changes were observed in the CG. There were no significant changes in insulin sensitivity and androgens after the intervention with zinc sulfate. CONCLUSIONS Zinc increased the leptin concentrations in obese individuals, but did not modify insulin sensitivity and androgens.