Small, dense low-density lipoprotein and C-reactive protein in obese subjects with and without other criteria for the metabolic syndrome.

BACKGROUND: Although obesity is an important cardiovascular risk factor, growing evidence shows that a substantial portion of obese subjects can be considered metabolically healthy but obese (MHO). However the extent to which obese subjects manifest small, dense low-density lipoprotein (LDL) particles without other characteristics of the metabolic syndrome (MS) remains unknown. OBJECTIVE: The purpose of this study was to determine the difference between MHO (only meeting the obesity criteria) and obese subjects meeting all the criteria for the MS with regard to LDL size and high-sensitivity C-reactive protein (hs-CRP), as a biomarker of inflammation. METHODS: Two hundred obese subjects (168 women, mean age 36.5 ± 5 years [range, 20-60]; mean body mass index [BMI; calculated as kg/m(2)] 39 ± 5 [range, 30-80.4]) were studied for LDL particles size and hs-CRP levels. RESULTS: Of 200 enrolled obese subjects, 55 were defined MHO subjects meeting only obesity criteria. The other 145 met all five criteria and were defined as having MS. Although MHO and MS subjects had similar BMI, MHO subjects had a lower percentage of small LDL particles (8% vs 29%, P < 0.001), higher average LDL diameter (274 ± 5 vs 270 ± 7 Å, P < 0.001), and lower hs-CRP levels (P < 0.05) than MS patients. CONCLUSION: The major finding of this study is that MHO subjects compared to equally obese subjects meeting the criteria of the MS have statistically significant differences in size of LDL and concentration of hs-CRP. However, the absolute differences are very small and of uncertain clinical significance.

Normal serum alanine aminotransferase activity in uncomplicated obesity.

AIM: To evaluate serum alanine aminotransferase (ALT) activity in a well-characterized group of uncomplicated obese subjects and its correlation with insulin resistance, plasma adiponectin, and leptin concentrations. METHODS: One hundred and five uncomplicated obese subjects (87 women, 18 men, age 34.3+/-9.6 years, BMI 39.9+/-8.3 kg/m(2)) were studied. Serum ALT activity was evaluated. Insulin sensitivity was assessed by euglycemic hyperinsulinemic clamp (M index) and fasting insulin. Plasma leptin and adiponectin levels were also measured. RESULTS: Serum ALT concentration in the whole group of uncomplicated obese subjects was 17.73+/-6.33 U/L with none of the subjects presenting ALT levels greater than 43 U/L and only 9 (11%) women and 3 (19%) men showed ALT levels >19 and >30 U/L for women and men, respectively. No significant difference was detected in serum ALT levels between severe obese subjects (BMI >40 kg/m(2)) and those with BMI <40 kg/m(2) (18.63+/-6.25 vs 17.26+/-6.02 U/L). ALT was significantly correlated with fasting insulin (r = 0.485, P = 0.02) and triglycerides (r = 0.358, P = 0.03). CONCLUSION: Serum ALT activity is practically normal in uncomplicated obese subjects, independently of their obesity degree. These findings suggest the role of obesity-related comorbidities and not of BMI as main risk factors for elevated ALT levels in obese subjects.

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.

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.

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.

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.

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.

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.