Anu Turpeinen

A high-trans fatty acid diet and insulin sensitivity in young healthy women

Epidemiological and experimental studies suggest that a diet rich in saturated fat affects insulin sensitivity. Monoenes and dienes that have an usaturated bond with the trans configuration (trans fatty acids) resemble saturated fatty acids with respect to structure, but no published data are available on the effect of trans fatty acids on insulin sensitivity. Therefore, the effects of diets high in trans fatty acids (TFA diet) and oleic acid (monounsaturated fat [MUFA] diet) on glucose and lipid metabolism were studied in 14 healthy women. Subjects consumed both experimental diets for 4 weeks according to a randomized crossover study design. Both experimental diet periods were preceded by consumption of a standardized baseline diet for 2 weeks. The diets provided 36.6% to 37.9% of energy (E%) as fat. In the TFA diet, there was 5.1 E% trans fatty acids, and in the MUFA diet, 5.2 E% oleic acid, substituted for saturated fatty acids in the baseline diet. A frequently sampled intravenous glucose tolerance test (FSIGT) was performed at the end of the experimental diet periods. Glucose effectiveness (S(G)) and the insulin sensitivity index (S(I)) did not differ after the two experimental diet periods. There was also no difference in the acute insulin response between the diets. The total cholesterol to high-density lipoprotein (HDL) cholesterol ratio and serum total triglyceride, HDL, and low-density lipoprotein (LDL) triglyceride and apolipoprotein B (apoB) concentrations were higher (P < .05) after the TFA diet. In conclusion, in young healthy women, the TFA diet resulted in a higher total/HDL cholesterol ratio and an elevation in triglyceride and apo B concentrations but had no effect on glucose and insulin metabolism compared with the MUFA diet.

A high-stearic acid diet does not impair glucose tolerance and insulin sensitivity in healthy women

Results in epidemiological and experimental studies suggest that a diet rich in saturated fat may affect insulin sensitivity. However, no published data are available on the effect of stearic acid in this respect. Therefore, we examined the effects of a high-stearic acid diet and a high-oleic acid diet on glucose metabolism, serum lipids and lipoproteins, and blood coagulation factors in 15 healthy female subjects. Subjects followed the two experimental diets for 4 weeks according to a randomized crossover design. Both experimental diet periods were preceded by consumption of a baseline diet for 2 weeks. The diets provided 36% of energy (E%) as fat. In the experimental diets, 5 E% stearic or oleic acid was substituted for 5 E% of saturated fatty acids in the baseline diet. After the experimental diets, no differences were found in the insulin sensitivity index (mean+/-SEM, 5.4+/-1.9 v 5.2+/-1.6 x 10(-4) min(-1) x microU(-1) x mL(-1), nonsignificant [NS]), glucose effectiveness (0.026+/-0.006 v 0.026+/-0.003 min(-1), NS), or first-phase insulin reaction ([FPIR] 368+/-57 v 374+/-66 mU/L x min, NS). The concentration of serum lipids and lipoproteins and blood coagulation factors did not differ after the diet periods. In conclusion, a diet rich in stearic acid did not deteriorate glucose tolerance or insulin action in young healthy female subjects as compared with a diet rich in oleic acid.

Subjective and physiological cephalic phase responses to food in obese binge-eating women

OBJECTIVE The subjective and physiological cephalic phase reactivity to food was investigated in obese binge-eating women. METHOD Eleven obese binge-eating women and 10 obese nonbinge-eating women participated in a cephalic phase response test consisting of baseline, anticipation, food exposure, and free eating periods. Serum insulin, free fatty acids, and plasma glucose concentrations as well as salivation, feeling of hunger, and desire to eat were repeatedly measured during the test. RESULTS During the food exposure, the binge eaters reported more desire to eat than did the nonbinge eaters. No differences were found between the groups in the physiological cephalic phase responses except for the lower salivation in the binge eaters during the food exposure. The amount of food eaten after the food exposure was similar in both groups. DISCUSSION Binge-eating women are characterized by stronger subjective but not stronger physiological cephalic phase reactivity to food.

Demonstration of Regional Sympathetic Denervation of the Heart in Diabetes: Comparison between patients with NIDDM and IDDM

OBJECTIVE Global myocardial uptake of 123I-metaiodobenzylguanidine (MIBG) has been shown to be decreased in diabetic patients with autonomic neuropathy, indicating cardiac sympathetic dysfunction. However, possible differences in myocardial MIBG distribution between NIDDM and IDDM diabetic patients are not known. RESEARCH DESIGN AND METHODS Regional myocardial distribution of 123I-MIBG was studied in seven male IDDM patients (age 45 ± 2 years, duration of diabetes 30 ± 3 years, means ± SE) and 13 NIDDM patients (8 men, 5 women, age 59 ± 2 years, duration of diabetes 10 ± 1 years). A dual-tracer single-photon emission tomography was carried out with 123I-MIBG and 99mTc-methoxyisobutylisonitrrile to asses simultaneously myocardial sympathetic innervation and perfusion at rest. Conventional autonomic nervous function tests, power spectral analysis of heart rate variability, and echocardiography were performed for assessments of autonomic function and cardiac dimensions and function. RESULTS Autonomic nervous function tests and echocardiography showed similar results in IDDM and NIDDM patients. Despite this, global myocardial MIBG uptake (0.43 ± 0.04 vs. 0.59 ± 0.06, P = 0.03) and MIBG heart-to-liver ratio (0.59 ± 0.03 vs. 0.68 = 0.03, P = 0.05) were lower in NIDDM compared with IDDM patients. Regional distribution of MIBG uptake and regional MIBG/perfusion ratio revealed significantly reduced uptake in NIDDM patients especially in the inferoposterior segments of the left ventricle compared with IDDM patients. Difference in age between NIDDM and IDDM patients did not explain the results. CONCLUSIONS Reduced myocardial MIBG uptake was found in NIDDM patients compared withthe uptake in IDDM patients, particularly involving inferoposterior segments.Regional sympathetic damage not detectable with conventional autonomic function tests is relatively common in NIDDM.

Prediction of atrial fibrillation after coronary artery bypass grafting by measuring atrial peptide levels and preoperative atrial dimensions

OBJECTIVE We prospectively tested the hypothesis that atrial enlargement and increased level of atrial natriuretic peptide, N-terminal atrial natriuretic peptide and brain natriuretic peptide would predict atrial fibrillation after coronary artery bypass grafting. METHODS Eighty-eight elective coronary artery bypass grafting patients had preoperative echocardiographic assessment. The level of atrial natriuretic peptide, N-terminal atrial natriuretic peptide and brain natriuretic peptide were measured preoperatively. Patients were ECG- monitored during the whole hospital stay. RESULTS Thirty one (35.2%) patients had postoperative atrial fibrillation. In univariate analysis increased age (P=0.003), enlargement of left and right atria (P=0.002 and P=0.004, respectively) and increased level of preoperative atrial natriuretic peptide and N-terminal atrial natriuretic peptide (P=0.016 and P=0.03, respectively) were associated with postoperative atrial fibrillation. There was correlation between the age and level of N-terminal atrial natriuretic peptide (r=0.45 and P<0.001). In multivariate analysis only age and the left atrial enlargement were independent predictors of postoperative atrial fibrillation (P=0.02 and P=0.01). CONCLUSION Left atrial enlargement was independent predictor for postoperative atrial fibrillation. However, atrial peptides were associated with age and did not independently predict postoperative atrial fibrillation. In addition, the wide variation of the peptide levels renders the implementation of this measure in clinical practice superfluous.

Metoprolol Versus Amiodarone in the Prevention of Atrial Fibrillation After Cardiac Surgery: A Randomized Trial

BACKGROUND Current guidelines recommend β-blockers as the first-line preventive treatment of atrial fibrillation (AF) after cardiac surgery. Despite this, 19% of physicians report using amiodarone as first-line prophylaxis of postoperative AF. Data directly comparing the efficacy of these agents in preventing postoperative AF are lacking. OBJECTIVE To determine whether intravenous metoprolol and amiodarone are equally effective in preventing postoperative AF after cardiac surgery. DESIGN Randomized, prospective, equivalence, open-label, multicenter study. (ClinicalTrials.gov registration number: NCT00784316) SETTING 3 cardiac care referral centers in Finland. PATIENTS 316 consecutive patients who were hemodynamically stable and free of mechanical ventilation and AF within 24 hours after cardiac surgery. INTERVENTION Patients were randomly assigned to receive 48-hour infusion of metoprolol, 1 to 3 mg/h, according to heart rate, or amiodarone, 15 mg/kg of body weight daily, with a maximum daily dose of 1000 mg, starting 15 to 21 hours after cardiac surgery. MEASUREMENTS The primary end point was the occurrence of the first AF episode or completion of the 48-hour infusion. RESULTS Atrial fibrillation occurred in 38 of 159 (23.9%) patients in the metoprolol group and 39 of 157 (24.8%) patients in the amiodarone group (P = 0.85). However, the difference (-0.9 percentage point [90% CI, -8.9 to 7.0 percentage points]) does not meet the prespecified equivalence margin of 5 percentage points. The adjusted hazard ratio of the metoprolol group compared with the amiodarone group was 1.09 (95% CI, 0.67 to 1.76). LIMITATIONS Caregivers were not blinded to treatment allocation, and the trial evaluated only stable patients who were not at particularly elevated risk for AF. The withdrawal of preoperative β-blocker therapy may have increased the risk for AF in the amiodarone group. CONCLUSION The occurrence of AF was similar in the metoprolol and amiodarone groups. However, because of the wide range of the CIs, the authors cannot conclude that the 2 treatments were equally effective. PRIMARY FUNDING SOURCE The Finnish Foundation for Cardiovascular Research and the Kuopio University EVO Foundation.

Cardiac sympathetic activity is associated with inflammation and neurohumoral activation in patients with idiopathic dilated cardiomyopathy

Background:  Idiopathic dilated cardiomyopathy (IDC) is characterized by sympathetic nervous overactivity, inflammation and neurohumoral activation; however, their interrelationships are poorly understood.

Long-term effect of acetyl-L-carnitine on myocardial123I-MIBG uptake in patients with diabetes

Carnitine derivatives may have beneficial effects on cardiac and nerve function in patients with diabetes. The aim of this study was to investigate the effect of acetyl-L-carnitine (ALC) on myocardial sympathetic nervous function as measured with123I-meta-iodobenzyl guanidine (MIBG) and single-photon emission tomography (SPET) in 19 patients with diabetes (placebo group,n=6; ALC group,n=13) at the beginning and at the end of a 1-year randomized, placebo-controlled, doubleblind trial. The coefficient of variation for the MIBG analysis was 4%. In patients who were given a placebo, global myocardial MIBG uptake deteriorated during the study (MIBG uptake 1-year follow-up/baseline, 0.86±0.05, mean±standard error of mean), whereas in patients treated with ALC, MIBG uptake did not change significantly (1-year follow-up/baseline, 1.07±0.08; p=0.03 between the groups). On the basis of these preliminary data, we conclude that long-term treatment with ALC may be of potential value in preventing the progressive loss of myocardial sympathetic nervous function in patients with diabetes. MIBG-SPET is a sensitive and thus valuable method in assessing the development of myocardial sympathetic nervous dysfunction.

Determinants of the Cephalic-Phase Insulin Response in Obese Nondiabetic Subjects

Large interindividual variation is characteristic of the cephalic-phase insulin response (CPIR). Our aim was to examine the largely unknown determinants of CPIR in obese nondiabetic subjects before and after weight reduction. After a 12-hour overnight fast, 20 healthy, obese (body mass index, 31.1 to 41.4 kg/m2) subjects were individually exposed to food without being allowed to eat it. Levels of insulin, glucose, C-peptide, free fatty acids, and salivation, together with assessments of feeling of hunger and desire to eat, were measured during the experiment. Subjects were divided into three groups according to CPIR before the weight reduction: positive (PR), intermediate (IR), and negative (NR) responders. CPIR measurements before and after weight reduction correlated significantly with each other (r = .61, P < . 01,n=18). At the beginning of the study, NR had higher fasting plasma glucose and insulin values, as well as higher postload plasma glucose values, as compared with PR and IR. These differences disappeared after weight reduction. In an intravenous glucose tolerance test (IVGTT) performed 9 to 12 months afterward, first-phase insulin secretion was significantly lower in NR. Thus, the negative CPIR during visual and olfactory exposure to food-related stimuli may be related to the attenuated first-phase insulin secretion and mildly impaired glucose metabolism, possibly related to insulin resistance.