Biomedical subjects

Maria Cristina Ribaudo

Publications and source records attributed to Maria Cristina Ribaudo.

14 recordsLinked to original sources

PubMed2006

Aminotransferase activity in morbid and uncomplicated obesity: predictive role of fasting insulin.

BACKGROUND AND AIMS: An elevation in liver enzymes and, most notably, high serum alanine aminotransferase (ALT) activity, has been correlated with metabolic syndrome and obesity. However, whether obesity per se or obesity-related co-morbidities affect aminotransferase activity is still unclear. In this study we sought to evaluate serum aminotransferase activity in morbid and uncomplicated obese subjects METHODS: In this cross-sectional study, serum aminotransferase activity, anthropometric and metabolic parameters were assessed in 290 morbid and 105 uncomplicated consecutive obese subjects matched for body mass index (BMI) (40.1+/-6.8 vs. 39.9+/-8.3 kg/m(2), respectively), age (35.9+/-10 vs. 34.8+/-9.6 years, respectively), sex distribution and duration of obesity. RESULTS: Uncomplicated obese subjects showed significantly lower serum ALT activity (17.58+/-6.3 (range 10-39) vs. 23.43+/-16 (range 12-89) U/l, (p<0.001)), and lower aspartate aminotransferase (AST), AST/ALT ratios and gamma-glutamyltranspeptidase (gammaGT) (p<0.01 for all) than morbid obese subjects. Only 11% women and 19% men in the uncomplicated obese group showed high ALT levels, while ALT activity was high in 48% women and 51% men in the morbid obese group. Fasting insulin was the best correlate of ALT activity (R(2)=0.21, p=0.003). CONCLUSIONS: Our findings show that elevated ALT and AST activity are associated with increased fasting insulin and not with obesity per se, suggesting that the presence of insulin resistance, rather than BMI alone, plays a role in mediating the increased aminotransferase activity.

Adult↗

PubMed2006

Non-invasive evaluation of endothelial dysfunction in uncomplicated obesity: relationship with insulin resistance.

Obesity is associated with increased cardiovascular morbidity and amortality. Endothelial dysfunction, involved in the pathogenesis of cardiovascular events, has been demonstrated in obese patients with invasive techniques requiring artery catheterization. The aim of our investigation was to evaluate, with a non-invasive method readily employable on clinical grounds, impaired vasodilatation and its relationship with insulin resistance in uncomplicated obesity. 15 uncomplicated obese subjects (BMI = 36.6 +/- 3.2) and 10 lean controls (BMI = 22.9 +/- 1.25) were enrolled in this study. All subjects underwent measurement of endothelium-dependent (FBFr) vasodilatation by forearm venous occlusion pletysmography after increasing times of ischemia, and measurement of insulin sensitivity by the euglycemic hyperinsulinemic clamp technique (M index), by fasting glucose and insulin (HOMA-IR) and by oral glucose tolerance test (ISI index). Endothelium-independent (N-FBFr) vasodilatation was assessed as well. The FBFr was markedly blunted in obese patients versus lean controls (30 s: 2.12 +/- 0.34 vs. 3.63 +/- 0.22, P < 0.01; 60 s: 2.34 +/- 0.42 vs. 3.82 +/- 0.53, P < 0.01; 180 s: 3.20 +/- 0.45 vs. 7.15 +/- 0.35, P < 0.01; 300 s: 4.08 +/- 0.94 vs. 14.1 +/- 0.82, P < 0.001). The N-FBFr was not different in the two groups. High correlation was found between M index and FBFr at all ischemia times. HOMA-IR and ISI were not related with FBFr. The non-invasive evaluation of endothelial dysfunction by a simple and reliable method based on venous occlusive plethysmography shows high correlation between impaired endothelium-dependent vasodilatation and insulin resistance in uncomplicated obesity. This non-invasive test of endothelial function may be routinely performed in the assessment of cardiovascular risk in uncomplicated obesity.

Adult↗

PubMed2005

Effect of acute hyperinsulinemia on ventricular repolarization in uncomplicated obesity.

BACKGROUND: Acute hyperinsulinemia has been shown to increase QTc interval in lean subjects, but data on obese subjects are still unclear. Aim of this study was to evaluate the effect of acute hyperinsulinemia on QTc interval and QTc dispersion in uncomplicated obesity. METHODS: We calculated QTc duration and QTc dispersion in 30 uncomplicated obese subjects (mean age 32.2 +/- 7, BMI 36.7 +/- 9.4 kg/m(2)) by measurements of 12-lead ECG recording during a euglycemic hyperinsulinemic clamp. RESULTS: Insulin infusion during the clamp did not significantly modify QTc interval and QTc dispersion in uncomplicated obese subjects (401.5 +/- 29.2 vs. 413.7 +/- 30.5; 35.4 +/- 10.5 vs. 38.7 +/- 14.5, respectively). CONCLUSIONS: Acute hyperinsulinemia seems to no significantly affect ventricular repolarization in uncomplicated obesity. Insulin resistance and the absence of diabetes and hypertension could explain, at least in part, this finding.

Acute Disease↗

PubMed2005

Prevalence of uncomplicated obesity in an Italian obese population.

OBJECTIVE: The existence of healthy obese subjects has been suggested but not clearly reported. We sought to address the prevalence of uncomplicated obesity and adverse risk factors in a large Italian obese population. RESEARCH METHODS AND PROCEDURES: This was a cross-sectional study of a population of consecutive Italian obese subjects. We studied 681 obese subjects (514 women and 167 men), with a mean age of 41.1+/-13.9 years (range, 16 to 77 years), mean BMI of 40.2+/-7.6 kg/m2 (range, 30 to 89.8 kg/m2), and a history of obesity for 20.5+/-7 years (range, 10.5 to 30 years). Anthropometric, metabolic, cardiac, and obesity-related risk factors were evaluated. RESULTS: The prevalence of uncomplicated subjects was 27.5%, independent of BMI and duration of obesity. The youngest group of obese subjects showed a higher, but not statistically significantly higher, prevalence of uncomplicated obesity. No statistical difference for the prevalence of impaired fasting glucose, glucose intolerance, high triglycerides, high total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol among BMI categories (from mild to extremely severe obesity degree) was found. Obese subjects with BMI>50 kg/m2 showed a higher prevalence of high blood pressure only when they were compared with the group with a BMI of 30 to 35 kg/m2 (p<0.01). Obese subjects with BMI>40 kg/m2 showed a higher prevalence of hyperinsulinemia than subjects with BMI 30 to 35 kg/m2 (p<0.01). DISCUSSION: This study shows that a substantial part of an Italian obese population has uncomplicated obesity, and the prevalence of adverse risk factors in this sample is unexpectedly low and partially independent of obesity degree. Uncomplicated obesity could represent a well-defined clinical entity.

Adolescent↗

PubMed2005

Relationship of thyroid function with body mass index, leptin, insulin sensitivity and adiponectin in euthyroid obese women.

BACKGROUND: A possible relationship between thyroid hormones and adipose tissue metabolism in humans has been suggested. Aim of the study We sought to evaluate thyroid function and its possible relationship with body mass index (BMI), leptin, adiponectin and insulin sensitivity in euthyroid obese women. MATERIALS AND METHODS: Eighty-seven uncomplicated obese women (mean age 34.7 +/- 9 years, mean BMI 40.1 +/- 7 kg/m(2)) were studied. Levels of TSH, free thyroxine (FT4), free triiodothyronine (FT3), plasma adiponectin and leptin were evaluated. Insulin sensitivity was assessed by euglycaemic hyperinsulinaemic clamp (M index), fasting insulin and HOMA-IR. RESULTS: Uncomplicated obese women with BMI > 40 kg/m(2) showed higher serum TSH than obese subjects with BMI < 40 kg/m(2) (P < 0.01). TSH was correlated with BMI (r = 0.44, P = 0.01) leptin (r = 0.41, P = 0.01), leptin/BMI ratio (r = 0.33, P = 0.03), body surface area (r = 0.26, P = 0.05), HOMA-IR (r = 0.245, P = 0.05) and inversely with adiponectin (r = -0.25, P = 0.05) and M index (r = -0.223 P = 0.05). CONCLUSIONS: Our data show that, although thyroid function was normal in the studied obese population, TSH and BMI were positively related. TSH has been found to be correlated also with leptin adjusted for BMI. TSH could represent a marker of altered energy balance in severe, but uncomplicated obese women.

Adiponectin↗

PubMed2004

Acute insulin infusion decreases plasma ghrelin levels in uncomplicated obesity.

BACKGROUND: Plasma ghrelin levels have been shown to decrease after insulin infusion in lean subjects. Nevertheless, the mechanism of the suggested inhibitory effect of insulin on ghrelin is still unclear and no data about the effect of acute insulin infusion on plasma ghrelin concentration in obese subjects are available. OBJECTIVE: We sight to evaluate plasma ghrelin concentration during an hyperinsulinemic euglycemic clamp in uncomplicated obese subjects. METHODS: 35 uncomplicated obese subjects, body mass index (BMI) 43.3+/-10.1 kg/m(2), 33 women and 2 men, mean age 34.9+/-10, with a history of excess fat of at least 10 years underwent euglycemic hyperinsulinemic clamp. Blood samples for ghrelin were performed at baseline and steady state of euglycemic insulin clamp. RESULTS: Ghrelin concentrations decreased over time to 10.6+/-15% (range 2-39%) of baseline, from a mean of 205.53+/-93.79 pg/ml to 179.03+/-70.43 pg/ml during the clamp (95% CI, 10.69 to 36.44, P<0.01). In a univariate linear regression analysis baseline plasma ghrelin levels were inversely correlated to BMI (r=-0.564, P=0.04). A linear positive trend between whole body glucose utilization (M(FFMkg) index) and ghrelin reduction during the clamp was found (chi(2) 3.05, p=0.05). CONCLUSIONS: Our data seem to suggest that hyperinsulinemia during a euglycemic clamp is able to suppress plasma ghrelin concentrations in uncomplicated obesity. This effect appears to be positively related to insulin sensitivity.

Adult↗

PubMed2004

Relation between epicardial adipose tissue and left ventricular mass.

Visceral adiposity is a cardiovascular risk factor of growing interest. This study sought to evaluate the hypothesis of a relation between epicardial adipose tissue, the visceral adipose tissue deposited around the heart, and left ventricular morphology in healthy subjects with a wide range of adiposity. We found for the first time that an increase in epicardial fat is significantly related to an increase in left ventricular mass.

Adipose Tissue↗

PubMed2004

Adapted changes in left ventricular structure and function in severe uncomplicated obesity.

OBJECTIVE: A massive amount of fat tissue, as that observed in obese subjects with BMI over 50 kg/m(2), could affect cardiac morphology and performance, but few data on this issue are available. We sought to evaluate cardiac structure and function in uncomplicated severely obese subjects. RESEARCH METHODS AND PROCEDURES: We studied 55 uncomplicated severely obese patients, 40 women, 15 men, mean age 35.5 +/- 10.2 years, BMI 51.2 +/- 8.8 kg/m(2), range 43 to 81 kg/m(2), with a history of fat excess of at least 10 years, and 55 age-matched normal-weight subjects (40 women, 15 men, mean BMI 23.8 +/- 1.2 kg/m(2)) as a control group. Each subject underwent an echocardiogram to evaluate left ventricular (LV) mass and geometry and systolic and diastolic function. RESULTS: Severely obese subjects showed greater LV mass and indexed LV mass than normal-weight subjects (p < 0.01 for all parameters). Nevertheless, LV mass was appropriate for sex, height(2.7), and stroke work in most (77%) uncomplicated severely obese subjects. In addition, no significant difference in LV mass indices and LV mass appropriateness between obese subjects with BMI > or = 50 kg/m(2) and those with BMI < or = 50 kg/m(2) was found. Obese subjects also showed higher ejection fraction and midwall shortening than normal-weight subjects (p = 0.05 and p < 0.01, respectively), suggesting a hyperdynamic systolic function. No significant difference in systolic performance between obese subjects with BMI > or = 50 kg/m(2) and those with BMI < or = 50 kg/m(2) was seen. DISCUSSION: Our data show that uncomplicated severe obesity, despite the massive fat tissue amount, is associated largely with adapted and appropriate changes in cardiac structure and function.

Adaptation, Physiological↗

PubMed2004

The common PPAR-gamma2 Pro12Ala variant is associated with greater insulin sensitivity.

Several genetic variants of peroxisome proliferator-activated receptor-gamma2 (PPAR-gamma2) have been identified, among which Pro12Ala, a missense mutation in exon 2, is highly prevalent in Caucasian populations. Up to now, conflicting results with regard to the association between this mutation and complex traits, such as obesity, insulin sensitivity and Type 2 diabetes, have been reported. We investigated the influence of the Pro12Ala polymorphism of PPAR-gamma2 on insulin sensitivity in a large Italian population sample, n=1215, in whom extensive clinical and biochemical analyses were performed. To estimate the insulin sensitivity status, the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated; in the obese/overweight subjects an oral glucose tolerance test (OGTT) was also performed and the Matsuda insulin sensitivity index (ISI) calculated. The insulin secretion index (homeostasis model assessment of percent beta-cell function, HOMA-beta%) was utilized to evaluate beta-cell function. The effect of the Pro12Ala polymorphism on quantitative variables was tested using multiple linear regression analysis. X12Ala (either Pro12Ala or Ala12Ala) genotype was associated with significantly lower fasting insulin levels compared to Pro/Pro (P=0.01 after correction for multiple comparisons) in all subjects. Consistent with this finding, significantly lower HOMA-IR was observed in X12Ala carriers (P=0.013 after correction for multiple comparisons) in all cohort. Moreover, no significant interaction effect was observed between body mass index and X12Ala polymorphism and between gender and X12Ala polymorphism in modulating insulin sensitivity. Our observations substantially extend previous findings and demonstrated that X12Ala variant is significantly associated with greater insulin sensitivity.

Amino Acid Substitution↗

PubMed2003

Epicardial fat from echocardiography: a new method for visceral adipose tissue prediction.

OBJECTIVE: To validate transthoracic echocardiography as an easy and reliable imaging method for visceral adipose tissue (VAT) prediction. VAT is recognized as an important indicator of high cardiovascular and metabolic risk. Several methods are applied to estimate VAT, with different results. RESEARCH METHODS AND PROCEDURES: We selected 60 healthy subjects (29 women, 31 men, 49.5 +/- 16.2 years) with a wide range of body mass indexes. Each subject underwent transthoracic echocardiogram and magnetic resonance imaging (MRI) to measure epicardial fat thickness on the right ventricle. Measurements of epicardial adipose tissue thickness were obtained from the same echocardiographic and MRI views and points. MRI was also used to measure VAT cross-sectional areas at the level of L4 to L5. Anthropometric indexes were also measured. RESULTS: Subjects with predominant visceral fat accumulation showed higher epicardial adipose tissue thickness than subjects with predominant peripheral fat distribution: 9.97 +/- 2.88 vs. 4.34 +/- 1.98 (p = 0.005) and 7.19 +/- 2.74 vs. 3.43 +/- 1.64 (p = 0.004) in men and women, respectively. Simple linear regression analysis showed an excellent correlation between epicardial adipose tissue and waist circumference (r = 0.895, p = 0.01) and MRI abdominal VAT (r = 0.864, p = 0.01). Multiple regression analysis showed that epicardial adipose tissue thickness (r(2) = 0.442, p = 0.02) was the strongest independent variable correlated to MRI VAT. Bland test confirmed the good agreement between the two methods. DISCUSSION: Epicardial adipose tissue showed a strong correlation with anthropometric and imaging measurements of VAT. Hence, transthoracic echocardiography could be an easy and reliable imaging method for VAT prediction.

Adipose Tissue↗

PubMed2003

Relationship of insulin sensitivity and left ventricular mass in uncomplicated obesity.

OBJECTIVE: We studied uncomplicated obesity as a model to evaluate the influence of insulin sensitivity per se on left ventricular mass (LVM) and geometry. RESEARCH METHODS AND PROCEDURES: We selected 50 obese subjects (BMI > 30 kg/m(2); 38 women and 12 men; mean age, 38.4 +/- 10 years; BMI, 36.4 +/- 10.5 kg/m(2)) with normal blood pressure, glucose tolerance, and plasmatic lipid levels. Thirty lean subjects formed the control group. Each subject underwent euglycemic insulin clamp (7 pmol/min per kg) to evaluate whole body glucose use (M index) and echocardiogram to calculate LVM and indexed LVM. RESULTS: Insulin-resistant obese subjects had higher LVM, LVM/h(2.7), LVM/body surface area, and LVM/fat-free mass(kg) (p = 0.001; p = <0.001 p = 0.001, and p = 0.04, respectively) than obese subjects with normal insulin sensitivity. Multivariate regression analysis showed that M index was the strongest independent correlate of LVM (r(2) = 0.34; p = 0.03). DISCUSSION: Our findings showed that insulin resistance, in uncomplicated obesity, is associated with an increased LVM and precocious changes of left ventricular geometry, whereas preserved insulin sensitivity is not associated with increased LVM.

Adult↗

PubMed2003

Different plasma ghrelin levels after laparoscopic gastric bypass and adjustable gastric banding in morbid obese subjects.

Gastric bypass has been reported to be associated with markedly suppressed plasma ghrelin levels, suggesting that it is one of the possible weight-reducing factors related to this procedure. The aim of this study was the evaluation of plasma ghrelin levels in patients who had undergone laparoscopic Roux-en-Y gastric bypass (LRYGBP) and laparoscopic adjustable silicone gastric banding (LASGB). Normoweight, obese subjects and patients who had undergone total gastrectomy were used as controls. In this cross-sectional study, we selected 10 subjects who underwent LASGB, 11 subjects with LRYGBP, 10 obese subjects, eight patients with total gastrectomy, and eight normoweight subjects. Plasma ghrelin, insulin, and glucose profiles were determined before and after breakfast and lunch. Obese subjects showed a ghrelin plasma level significantly lower than normoweight subjects (407.3 +/- 21.6 vs. 813 +/- 72.4 pg/ml, P < 0.01). Patients with LRYGBP showed baseline ghrelin levels lower than LASGB (213.5 +/- 73.9 vs. 314.2 +/- 84.3 pg/ml, P = 0.04). Both groups of patients who underwent bariatric surgical procedures also had ghrelin lower than normoweight and obese subjects (P < 0.01 and P < 0.05, respectively). Patients with total gastrectomy showed plasmatic ghrelin levels extremely lower than those in all other groups (32.6 +/- 18.7 pg/ml, P < 0.001 for all). The ghrelin profile in both groups of subjects who underwent LRYGBP and LASGB did not show any meal-related changes as observed in obese and normoweight control groups. Significant difference in plasma ghrelin levels between LRYGBP and LASGB was found, suggesting that both procedures could induce weight loss by different mechanisms in which ghrelin could be involved.

Adipose Tissue↗

PubMed2003

Echocardiographic epicardial adipose tissue is related to anthropometric and clinical parameters of metabolic syndrome: a new indicator of cardiovascular risk.

Metabolic syndrome is related to multiple cardiovascular risk factors. Visceral adipose tissue (VAT) plays a key role in metabolic syndrome. Easy detection of VAT could be an important tool to increase knowledge of metabolic syndrome. The objective of this study was to study the relationship of echocardiographic epicardial adipose tissue to anthropometric and clinical parameters of metabolic syndrome. We selected 72 consecutive subjects, 46.5 +/- 17.4 yr of age, with a body mass index between 22 and 47 kg/m(2). Each subject underwent transthoracic echocardiogram to measure epicardial fat thickness on right ventricle and magnetic resonance imaging to calculate visceral adipose tissue. Anthropometric, metabolic, and cardiac parameters were also evaluated. Echocardiographic epicardial adipose tissue showed a very good correlation with magnetic resonance imaging abdominal VAT and epicardial fat measurement (Bland-Altman plot and linear regression). Multiple regression analysis showed that waist circumference (r(2) = 0.428; P = 0.01), diastolic blood pressure (r(2) = 0. 387; P = 0.02), and fasting insulin (r(2) = 0.387; P = 0.03) were the strongest independent variables correlated with epicardial adipose tissue. Echocardiographic epicardial adipose tissue could be applied as an easy and reliable imaging indicator of VAT and cardiovascular risk.

Adipose Tissue↗

PubMed2002

Influence of excess fat on cardiac morphology and function: study in uncomplicated obesity.

OBJECTIVE: To evaluate whether or not "uncomplicated" obesity (without associated comorbidities) is really associated with cardiac abnormalities. RESEARCH METHODS AND PROCEDURES: We evaluated cardiac parameters in obese subjects with long-term obesity, normal glucose tolerance, normal blood pressure, and regular plasma lipids. We selected 75 obese patients [body mass index (BMI) >30 kg/m(2)], who included 58 women and 17 men (mean age, 33.7 +/- 11.9 years; BMI, 37.8 +/- 5.5 kg/m(2)) with a > or =10-year history of excess fat, and 60 age-matched normal-weight controls, who included 47 women and 13 men (mean age, 32.7 +/- 10.4 years; BMI, 23.1 +/- 1.4 kg/m(2)). Each subject underwent an oral glucose tolerance test to exclude impaired glucose tolerance or diabetes mellitus, bioelectrical impedance analysis to calculate fat mass and fat-free mass, and echocardiography. RESULTS: Obese patients presented diastolic function impairment, hyperkinetic systole, and greater aortic root and left atrium compared with normal subjects. No statistically significant differences between obese subjects and normal subjects were found in indexed left ventricular mass (LVM/body surface area, LVM/height(2.7), and LVM/fat-free mass(kg)), and no changes in left ventricular geometry were observed. No statistically significant differences in cardiac parameters between extreme (BMI > 40 kg/m(2)) and mild obesity (BMI < 35 kg/m(2)) were observed. DISCUSSION: In conclusion, our data showed that obesity, in the absence of glucose intolerance, hypertension, and dyslipidemia, seems to be associated only with an impairment of diastolic function and hyperkinetic systole, and not with left ventricular hypertrophy.

Adipose Tissue↗