Giovanni Annuzzi

Liver Fat Is Reduced by an Isoenergetic MUFA Diet in a Controlled Randomized Study in Type 2 Diabetic Patients

OBJECTIVE To evaluate the effects of qualitative dietary changes and the interaction with aerobic exercise training on liver fat content independent of weight loss in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS With use of a factorial 2 × 2 randomized parallel-group design, 37 men and 8 women, aged 35–70 years, with type 2 diabetes in satisfactory blood glucose control on diet or diet plus metformin treatment were assigned to one of the following groups for an 8-week period: 1) high-carbohydrate/high-fiber/low–glycemic index diet (CHO/fiber group), 2) high-MUFA diet (MUFA group), 3) high-carbohydrate/high-fiber/low–glycemic index diet plus physical activity program (CHO/fiber+Ex group), and 4) high-MUFA diet plus physical activity program (MUFA+Ex group). Before and after intervention, hepatic fat content was measured by 1H NMR. RESULTS Dietary compliance was optimal and body weight remained stable in all groups. Liver fat content decreased more in MUFA (−29%) and MUFA+Ex (−25%) groups than in CHO/fiber (−4%) and CHO/fiber+Ex groups (−6%). Two-way repeated-measures ANOVA, including baseline values as covariate, showed a significant effect on liver fat content for diet (P = 0.006), with no effects for exercise training (P = 0.789) or diet-exercise interaction (P = 0.712). CONCLUSIONS An isocaloric diet enriched in MUFA compared with a diet higher in carbohydrate and fiber was associated with a clinically relevant reduction of hepatic fat content in type 2 diabetic patients independent of an aerobic training program and should be considered for the nutritional management of hepatic steatosis in people with type 2 diabetes.

A controlled study on the effects of n-3 fatty acids on lipid and glucose metabolism in non-insulin-dependent diabetic patients.

Eight male non-insulin-dependent diabetic patients participated in a double-blind randomized cross-over study (2 weeks for each period) evaluating the effects of 10 g/day fish oil dietary supplementation on glucose and lipid metabolism. Fasting serum triglyceride concentrations were decreased by fish oil because of a reduction in VLDL (1.4 +/- 0.2 vs. 1.9 +/- 0.2 mmol/l, P less than 0.025). LDL cholesterol concentration was instead increased (3.4 +/- 0.3 vs. 2.8 +/- 0.3 mmol/l, P less than 0.025) and net changes in VLDL triglyceride and in LDL cholesterol were inversely correlated (r = -0.86, P less than 0.01). Plasma free fatty acids concentrations and turnover rate [( 3H]palmitate method) were similar after fish oil and placebo. Fish oil supplement did not induce significant changes in fasting blood glucose (8.1 +/- 1.1 vs. 8.5 +/- 1.2 mmol/l) and average daily blood glucose (BG) (9.4 +/- 3.2 vs. 9.3 +/- 3.5 mmol/l). Glucose stimulated plasma insulin response during a hyperglycemic clamp was not significantly influenced by fish oil both in the early phase and during steady state. Insulin sensitivity (M/I index) was also unchanged. In conclusion, this study shows that a dietary supplement of fish oil decreases plasma triglyceride levels in non-insulin-dependent diabetic patients, an increased conversion rate of VLDL to LDL playing a role in this change. With this dosage of fish oil no relevant variations in glycemic control, insulin secretion and insulin sensitivity occurred.

NaCl sensitivity of essential hypertensive patients is related to insulin resistance.

Objective To evaluate insulin sensitivity of essential hypertensive patients with different salt sensitivities of blood pressure in the absence of confounding factors such as obesity, glucose intolerance and the inclusion both of normotensive and of hypertensive subjects that have affected most previous studies. Patients Ninety-nine patients with untreated mild or moderate essential hypertension, World Health Organization class I–II, participated in the study. Methods Salt sensitivity was estimated using the Weinberger protocol with minor modifications and the patients were classified into tertiles of salt sensitivity. Results Patients with high NaCl sensitivities were slightly older and had somewhat higher blood pressures than did subjects with low salt sensitivities. Plasma renin activity significantly decreased with increasing salt sensitivity. There were no differences among the three groups in terms of body mass index, fasting blood glucose and insulin plasma levels. There were no differences among the groups in the integrated glucose and insulin response to a standard oral-glucose tolerance test. However, there was a significant difference in insulin sensitivity between two subgroups of the upper and lower tertile of salt sensitivity, the salt-sensitive hypertensives having a markedly lower utilization of glucose than did the salt-resistant ones, with a minor overlap (5.4 ± 0.6 versus 7.4 ± 0.3 mg/kg per min, P < 0.01). Conclusions This study showed that essential hypertensive patients with high NaCl sensitivities were relatively insulin resistant compared with those with low NaCl sensitivities, independently of confounding factors such as age, obesity and glucose intolerance. Insulin resistance was not associated with overt hyperinsulinaemia among these patients.

Differential alterations of the concentrations of endocannabinoids and related lipids in the subcutaneous adipose tissue of obese diabetic patients.

BackgroundThe endocannabinoids, anandamide and 2-AG, are produced by adipocytes, where they stimulate lipogenesis via cannabinoid CB1 receptors and are under the negative control of leptin and insulin. Endocannabinoid levels are elevated in the blood of obese individuals and nonobese type 2 diabetes patients. To date, no study has evaluated endocannabinoid levels in subcutaneous adipose tissue (SAT) of subjects with both obesity and type 2 diabetes (OBT2D), characterised by similar adiposity and whole body insulin resistance and lower plasma leptin levels as compared to non-diabetic obese subjects (OB).Design and MethodsThe levels of anandamide and 2-AG, and of the anandamide-related PPARα ligands, oleoylethanolamide (OEA) and palmitoylethanolamide (PEA), in the SAT obtained by abdominal needle biopsy in 10 OBT2D, 11 OB, and 8 non-diabetic normal-weight (NW) subjects, were measured by liquid chromatography-mass spectrometry. All subjects underwent a hyperinsulinaemic euglycaemic clamp.ResultsAs compared to NW, anandamide, OEA and PEA levels in the SAT were 2-4.4-fold elevated (p < 0.05), and 2-AG levels 2.3-fold reduced (p < .05), in OBT2D but not in OB subjects. Anandamide, OEA and PEA correlated positively (p < .05) with SAT leptin mRNA and free fatty acid during hyperinsulinaemic clamp, and negatively with SAT LPL activity and plasma HDL-cholesterol, which were all specifically altered in OBT2D subjects.ConclusionsThe observed alterations emphasize, for the first time in humans, the potential different role and regulation of adipose tissue anandamide (and its congeners) and 2-AG in obesity and type 2 diabetes.

Sonographic hepatic-renal ratio as indicator of hepatic steatosis: comparison with 1H magnetic resonance spectroscopy

The aim of this study was to determine the diagnostic performance of ultrasound (US) in the quantitative assessment of steatosis by comparison with proton magnetic resonance spectroscopy ((1)H-MRS) as a reference standard. Three liver echo-intensity indices were derived: US hepatic mean gray level, hepatic-renal echo-intensity ratio (H/R), and hepatic-portal blood echo-intensity ratio. The (1)H-MRS degree of steatosis was determined as percentage fat by wet weight. Regression equations were used to estimate quantitatively hepatic fat content. The hepatic fat content by (1)H-MRS analysis ranged from 0.10% to 28.9% (median value, 4.8%). Ultrasound H/R was correlated with the degree of steatosis on (1)H-MRS (R(2)= 0.92; P < .0001), whereas no correlation with (1)H-MRS was found for hepatic mean gray level and hepatic-portal blood echo-intensity ratio. A receiver operating characteristic curve identified the H/R of 2.2 as the best cutoff point for the prediction of (1)H-MRS of at least 5%, yielding measures of sensitivity and specificity of 100% and 95%, respectively. In this pilot study, US H/R exhibits high sensitivity and specificity for detecting liver fatty changes. Our results indicate that quantitative evaluation of hepatic fat content can be performed using US H/R and could therefore be a valuable analytic tool in clinical investigation.

Ezetimibe beneficially influences fasting and postprandial triglyceride-rich lipoproteins in type 2 diabetes

INTRODUCTION Type 2 diabetes is associated with atherogenic abnormalities of postprandial triglyceride-rich lipoproteins. This study evaluated whether ezetimibe, by inhibiting intestinal cholesterol absorption, influences chylomicrons and VLDL particles at fasting and after a standard meal. METHODS By a double blind cross-over design 15 subjects with type 2 diabetes and hypercholesterolaemia followed in random order a 6-week treatment with ezetimibe 10mg+simvastatin 20 mg (EZE+S) or placebo+simvastatin 20 mg (P+S) and, after a 6-week wash-out period, crossed over to the other treatment (NCT00699023). At the end of each period lipids, apoB-48, and apoB-100 concentrations in plasma and lipoprotein fractions (separated by discontinuous density gradient ultracentrifugation) were determined before and over 6h following a high-fat test meal. RESULTS Compared with P+S, EZE+S induced, (a) beside a greater decrease in LDL cholesterol, (b) a significant decrease in chylomicron lipid content both at fasting and postprandially (4.4 ± 2.7 vs. 8.3 ± 8.7 mg/dl × 6 h total AUC for cholesterol, p < 0.05; 18 ± 12 vs. 29 ± 24 mg/dl triglyceride concentrations at 6h, p < 0.05), (c) a significant decrease in chylomicron postprandial apoB-48 (0.03 ± 0.03 vs. 0.09 ± 0.08 mg/l at 4 h, p < 0.05), and (d) significant fasting and postprandial decreases in the cholesterol content of VLDL, IDL, and LDL, as shown by the significant reduction of the cholesterol/triglyceride ratio in these lipoproteins. CONCLUSIONS A 6-week treatment with ezetimibe and simvastatin, compared to simvastatin alone, positively influences lipoprotein profile both at fasting and postprandially in type 2 diabetic patients by favouring the production of cholesterol-poor chylomicrons and VLDL particles that have less atherogenic potential.

Effects of Changing Amount of Carbohydrate in Diet on Plasma Lipoproteins and Apolipoproteins in Type II Diabetic Patients

Eight type II (non-insulin-dependent) normolipidemic diabetic patients (aged 45 ± 15 yr, body mass index 22 ± 2 kg/m2, means ± SD) treated with diet alone or diet plus oral hypoglycemic agents were given, in random order for periods of 15 days, two diets with different carbohydrate (CHO) (40 vs. 60% of total calories) and fat (20 vs. 40%) levels. Simple CHO, fiber, saturated fat, cholesterol, and polyunsaturated-saturated fat ratio were similar in the two diets. Total plasma cholesterol was not significantly affected by dietary changes; conversely, plasma triglyceride (1.38 ± 0.59 vs. 1.11 ± 0.39 mM, P < 0.05) and apolipoprotein Cll (3.8 ± 1 · 4 vs, 3.3 ± 0.8 mg/dl) increased significantly after the high-CHO low-fat diet. Among the various lipoproteins, very-low-density lipoprotein (VLDL) was the most affected by diet: VLDL cholesterol concentrations increased from 0.30 ± 0.19 to 0.43 ± 0.28 mM (P < 0.05), and triglyceride concentrations increased from 0.62 ± 0.33 to 0.88± 0.53 mM (P <0.05). In conclusion, increasing the amount of complex CHO in the diet induces an elevation of VLDL in normolipidemic, nonobese, mildly type II diabetic patients.

Predominant role of obesity/insulin resistance in oxidative stress development

Eur J Clin Invest 2012; 42 (1): 70–78

Insulin and Sulfonylurea Therapy in NIDDM Patients: Are the Effects on Lipoprotein Metabolism Different Even With Similar Blood Glucose Control?

This study evaluates the effects of insulin versus glibenclamide on lipoprotein metabolism at comparable levels of blood glucose control, in particular on the concentration and distribution of VLDL subfractions and lipolytic enzyme activities in nine NIDDM men (aged 56 ± 3 years, BMI 26.5 ± 0.9 kg/m2) (means ± SE) participating in a crossover study. After a 3-week washout period, patients were randomly assigned to 2-month treatment periods (insulin or glibenclamide); thereafter, each patient crossed to the other treatment. At the end of each period, mean daily blood glucose (MDBG), HbA1c, plasma lipids, lipoproteins (VLDL, LDL, HDL), lipoprotein subfractions (VLDL1, 2, 3; HDL2) HDL3), and post-heparin lipase activities (lipoprotein lipase [LPL], hepatic lipase [HL]) were evaluated. Although glucose control was similar at the end of both periods (MDBG 8.3 ± 0.3 vs. 7.9 ± 0.3 mmol/l HbA1c 7.4 ± 0.3 vs. 7.0 ± 0.2%, insulin versus glibenclamide), insulin compared with glibenclamide induced a significant reduction in plasma triglycerides (0.9 ± 0.1 vs. 1.1 ± 0.1 mmoH, P < 0.05), VLDL triglycerides (50.1 ± 12.2 vs. 63.6 ± 12.3 mg/dl, P < 0.02), VLDL1 lipid concentration (24.9 ± 7.5 vs. 39.9 ± 9.5 mg/dl, P < 0.006), and increased HDL2 cholesterol (25.2 ± 1.6 vs. 20.3 ± 1.3 mg/dl, P < 0.03). In terms of VLDL percentage subfraction distribution, with insulin, there was a decrease in the larger subfractions (VLDL1 26.5 ± 3.0 vs. 37.8 ± 3.4%, P < 0.02) and an increase in the smallest (VLDL3 47.3 ± 3.8 vs. 37.3 ± 3.3%, P < 0.05). Moreover, HL activity was significantly lower after insulin than after glibenclamide (HL 247.2 ± 22.3 vs. 263.5 ± 22.6 mU/ml, P < 0.05). In conclusion, compared with glibenclamide, insulin treatment (independent of variations in glucose control) is able to decrease significantly plasma triglycerides, to increase HDL2 cholesterol, and to reduce only the concentration of the larger VLDL subfractions, with a consequent redistribution of their profile.

Presence of very low density lipoprotein compositional abnormalities in Type 1 (insulin-dependent) diabetic patients; effects of blood glucose optimisation

SummaryPlasma lipoprotein compositional abnormalities were investigated in eight normolipidaemic (plasma cholesterol <5.70 mmol/l; triglyceride <2.03 mmol/l) young male Type 1 (insulin-dependent) diabetic patients (before and after a short period of optimised blood glucose control) and in nine healthy control subjects, matched for sex, age and body mass index. Free and esterified cholesterol, triglyceride, phospholipids were assayed in all lipoprotein classes (VLDL, IDL, LDL) and in HDL subclasses (HDL2 and HDL3); apoB was measured only in very low density lipoproteins (VLDL). All VLDL constituents were increased in the diabetic group, the differences being more striking for apoB (6.0±1.1 mg/dl vs 2.0±0.1 mg/dl, p<0.02), free cholesterol (0.27±0.04 mmol/l vs 0.13±0.02 mmol/l, p<0.02) and esterified cholesterol (0.32±0.08 mmol/l vs 0.13±0.01 mmol/l, p<0.05). Also HDL subfractions showed differences between the two groups: all HDL2 constituents were increased, while in HDL3 only triglyceride was significantly increased (0.11±0.01 mmol/l vs 0.08±0.004 mmol/l, p<0.02). After two weeks of optimised blood glucose control all VLDL constituents were reduced and particularly: esterified cholesterol (−39%, p<0.02), free cholesterol (−37%, p<0.05), apoB (− 35%, p<0.05). Expressing each VLDL constituent as percent of the total lipoprotein mass, it was evident that the diabetic VLDL was rich in cholesterol both esterified (8.4±1.0% vs 5.4±0.5%, p<0.02) and free (8.5±0.7% vs 5.5±0.3%, p<0.001), apo B (5.1±0.6% vs 2.6±0.3%, p<0.001) and depleted in triglyceride (57.0±1.7% vs 64.1±1.7%, p<0.001). Two weeks of optimised blood glucose control were not able to correct the abnormal composition of VLDL. In conclusion, Type 1 (insulin-dependent) diabetic patients, although normolipidaemic, show an abnormal VLDL composition suggesting an increased prevalence of smaller and, possibly, more atherogenic VLDL particles. This abnormality is not corrected by a short period of blood glucose optimisation.