[show abstract][hide abstract] ABSTRACT: Obesity is associated with abnormalities of the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis. The role of serum IGF-1 measurement for recognition of hypothalamic-pituitary diseases in obesity is still a matter of debate.
This study evaluated the serum levels of IGF-1 in a population of severely obese women before and after long-term weight loss obtained by laparoscopic adjustable gastric banding (LAGB). Eighty obese women with body mass index (BMI) of more than 34 kg/m(2) and 80 unrelated age-matched lean controls were enrolled. IGF-1 serum levels were measured together with BMI, liver volume, and intra-abdominal fat thickness assessed by ultrasound. Evaluation was repeated 2 years after LAGB.
Our results showed that mean IGF-1 levels in obese subjects before LAGB were significantly lower (p < 0.001) than that observed in age-matched controls. Age and BMI were independent predictors of serum IGF-1 values, overall accounting for 39 % of IGF-1 variability. The mean IGF-1 concentration significantly increased 2 years after LAGB. BMI reduction was independently associated with IGF-1 increase (r = -0.29, p < 0.001). For each point of BMI reduction, the mean increase of serum IGF-1 was 4.39 ng/mL.
(1) Severely obese women have low IGF-1 serum levels with respect to normal weight age-matched controls; (2) the extent of IGF-1 deficiency is proportional to increased BMI; (3) after LAGB a spontaneous raise of serum IGF-1 occurs, proportional to the extent of weight reduction; and (4) serum IGF-1 in severely obese subjects may have a limited value for detection of hypothalamic-pituitary diseases.
Obesity Surgery 05/2012; 22(8):1276-80. · 3.10 Impact Factor
[show abstract][hide abstract] ABSTRACT: Bariatric surgery allows stable body weight reduction in morbidly obese patients. In presurgical evaluation, obesity-related co-morbidities must be considered, and a multidisciplinary approach is recommended. Precise guidelines concerning the endocrinological evaluation to be performed before surgery are not available. The aim of this study was to evaluate the prevalence of common endocrine diseases in a series of obese patients scheduled for bariatric surgery.
We examined 783 consecutive obese subjects (174 males and 609 females) aged 18-65 years, who turned to the obesity centre of our department from January 2004 to December 2007 for evaluation before bariatric surgery. Thyroid, parathyroid, adrenal and pituitary function was evaluated by measurement of serum hormones. Specific imaging or supplementary diagnostic tests were performed when indicated.
The overall prevalence of endocrine diseases, not including type 2 diabetes mellitus, was 47.4%. The prevalence of primary hypothyroidism was 18.1%; pituitary disease was observed in 1.9%, Cushing syndrome in 0.8%, while other diseases were found in less than 1% of subjects. Remarkably, the prevalence of newly diagnosed endocrine disorders was 16.3%.
A careful endocrinological evaluation of obese subjects scheduled for bariatric surgery may reveal undiagnosed dysfunctions that require specific therapy and/or contraindicate the surgical treatment in a substantial proportion of patients. These results may help to define the extent of the endocrinological screening to be performed in obese patients undergoing bariatric surgery.
Obesity Surgery 10/2010; 21(1):54-60. · 3.10 Impact Factor
[show abstract][hide abstract] ABSTRACT: TSH-receptor (TSHR) has been found in a variety of cell types, including preadipocytes and adipocytes. In vitro, TSH-mediated preadipocyte and adipocyte responses include proliferation, differentiation, survival, and lipolysis. Objective To measure the response of serum leptin to exogenous administration of recombinant human TSH (rhTSH) in vivo. Patients One hundred patients with differentiated thyroid cancer already treated by total thyroidectomy and (131)I remnant ablation were enrolled. Mean (+/-s.e.m.) body mass index (BMI) was 26.9+/-0.6 kg/m(2). Methods Patients received a standard dose of rhTSH for measurement of thyroglobulin in the follow-up of their disease. Blood samples were taken for the assay of TSH and leptin before the first administration of rhTSH (time 0), and 24 h (time 1), 48 h (time 2), 72 h (time 3), and 96 h (time 4) after the first administration of rhTSH. Results Significant mean serum leptin increments, with respect to basal value, were 16, 13, 18, and 11% at times 1, 2, 3, and 4 respectively. Significant positive correlations of leptin-area under the curve with respect to basal leptin levels (r=0.43; P<0.0001) and BMI (r=0.32; P<0.005) were observed. Conclusions Acute rhTSH administration in hypothyroid subjects under l-thyroxine therapy produces a rise in serum leptin. This increase is proportional to the adipose mass suggesting that a functioning TSHR is expressed on the surface of adipocytes. The role that TSHR activation in adipocytes might play in physiological and pathological conditions remains a matter of investigation.
European Journal of Endocrinology 07/2010; 163(1):63-7. · 3.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Aim of this study was to investigate the effect of weight loss on structural and functional myocardial alterations in severely obese subjects treated with bariatric surgery.
Thirteen severely obese patients (2 males and 11 females) were enrolled in the study. All subjects underwent conventional 2D color Doppler echocardiography. The new ultrasonic techniques used were: (a) integrated backscatter for the analysis of myocardial reflectivity, referred to pericardial interface as expression of myocardial structure (increase in collagen content) and of cyclic variation index as expression of intrinsic myocardial contractility and (b) color Doppler myocardial imaging (CDMI) for the analysis of strain and strain rate (myocardial deformability). All subjects underwent bariatric surgery and were resubmitted to echocardiographic and biochemical examination 6-24 months after surgery.
The main finding of the present study was a quite complete normalization of myocardial functional and structural alterations after weight loss. In particular, the cyclic variation index at septum level improved from 14.6 +/- 7.0 before to 25.7 +/- 11.2 (means +/- SD) after surgery (controls: 36.2 +/- 9.1). Mean reflectivity at septum level significantly decreased from 55.8 +/- 9.5 to 46.5 +/- 8.8 (controls: 43.0 +/- 8.0). Also, the strain at septum level significantly improved after surgery (from -11.9 +/- 3.2 to -20.4 +/- 5.3; controls: -23.4 +/- 9).
This study establishes: (a) the utility of new ultrasonic techniques to detect very early structural and functional myocardial alterations in severely obese patients, and (b) the regression of these subclinical abnormalities after weight loss achieved by bariatric surgery.
[show abstract][hide abstract] ABSTRACT: Obesity is a well-established risk factor for congestive heart failure. Evidence has been provided indicating that insulin resistance could be the mediator between obesity and congestive heart failure, but the pathogenic mechanisms leading to myocardial alterations remain unclear. The aim of this study was to investigate, by ultrasonic integrated backscatter (IBS) analysis, subclinical alterations of left ventricular (LV) structure and function in severe obesity. Sixty consecutive, severely obese people, who were otherwise healthy (15 men, 45 women; mean age +/- SD = 31.8 +/- 7 years), were enrolled. A total of 48 sex- and age-matched nonobese healthy participants were recruited as control subjects. All participants underwent conventional 2-dimensional color Doppler echocardiography, pulsed wave Doppler tissue imaging at mitral annulus level, and IBS. The homeostasis model assessment insulin resistance index was used to assess insulin resistance; the index values in the obese group were significantly higher (mean +/- SD = 4.9 +/- 1.4) than in the control group (0.92 +/- 0.5, P < .0001). Obese patients had a greater LV mass index by height (58.5 +/- 14 g/m(2.7)) than did control subjects (37 +/- 8 g/m(2.7), P < .0001) because of compensation response to volume overload caused by a greater cardiac output (P < .02). Preload reserve was increased in obese patients, as demonstrated by the significant increase in left atrial dimension (P < .0001). This volumetric increase activated the Frank-Starling mechanism, and determined a significantly higher LV ejection fraction (P < .03) in obese patients as compared with control subjects. A slightly reduced LV diastolic function was demonstrated in obese patients (transmitral early to late peak diastolic transmitral flow velocities ratio = 1.1 +/- 0.7) as compared with control subjects (1.5 +/- 0.5, P < .02). Pulsed wave Doppler tissue imaging showed an impairment of diastolic LV longitudinal function and increased LV diastolic filling pressure. The IBS values at septum level, indexed by pericardium interface, were significantly higher for septum in the obese group (57.8 +/- 8%) than in the control group (42.3 +/- 9%, P < .0001). Additional IBS alterations were observed in the obese group, with a significantly lower cyclic variation index both at septum (P < .0001) and at posterior wall (P < .001) levels. A significant association was found between insulin resistance index and both the IBS index of myocardial reflectivity at septum level (expression of increased myocardial collagen content) or LV mass. In conclusion, this study demonstrates that obese patients exhibit myocardial structural and functional alterations related to insulin resistance and to LV volume overload, which could be considered the very early stage of incipient obesity cardiomyopathy.
Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 08/2006; 19(8):1063-71. · 2.98 Impact Factor
[show abstract][hide abstract] ABSTRACT: In this study, we evaluated the influence of height, weight, body mass index (BMI), body surface area, and body composition [total lean body mass (LBM) and fat body mass] on serum peak TSH levels obtained after recombinant human (rh)TSH. Furthermore, to verify whether the serum peak TSH influenced the efficacy of radioiodine ((131)I), we compared the rate of thyroid remnant ablation according to the patients' BMI.
We studied 105 patients with differentiated thyroid carcinoma who underwent rhTSH stimulation test. Serum TSH measurements were performed before and 24, 48, and 72 h after rhTSH administration. We also compared the rate of thyroid remnant ablation among 70 differentiated thyroid carcinoma patients with different BMI.
The serum peak TSH after rhTSH was significantly lower in overweight and obese subjects compared with normal-weight subjects (92.1 +/- 41.8, 82.4 +/- 24.2, and 112.7 +/- 46.3 microU/ml, respectively; P = 0.01) and in males compared with females (74.6 +/- 22.3 and 105.0 +/- 43.0 microU/ml, respectively; P = 0.0002). By univariate analysis, serum peak TSH was negatively related to weight, height, body surface area, BMI, LBM, and fat body mass, but only LBM was independently associated with serum peak TSH levels. Although it was confirmed that overweight and obese patients had a lower serum peak TSH, the rate of ablation did not differ among normal-weight, overweight, and obese patients.
With this study we demonstrated that LBM is the only parameter independently associated with serum peak TSH after rhTSH administration. However, the serum peak TSH does not influence the rate of (131)I remnant ablation.
[show abstract][hide abstract] ABSTRACT: Total body weight is usually employed to calculate the amount of l-T(4) to be administered in patients with thyroid diseases. The aim of this study was to evaluate the effect of body composition on l-T(4) requirements. Body composition was assessed by dual energy x-ray absorptiometry in 75 patients on TSH-suppressive l-T(4) therapy after conventional thyroid ablation for differentiated cancer. The mean daily dose of l-T(4) was lower in normal-weight (127.5 +/- 21.3 mug/d) vs. overweight (139.4 +/- 24.5) and obese (151.3 +/- 29.1) subjects. There was a much stronger association between the l-T(4) dosage and lean body mass (P < 0.001, r = 0.667) compared with fat mass (P = 0.023, r = 0.26). Measurement of regional tissue composition showed peripheral lean mass as the best correlate with the dose of l-T(4) (r = 0.679, P < 0.001) whereas no correlation was observed with peripheral fat mass. In conclusion, individual l-T(4) requirements are dependent on lean body mass. Age- and gender-related differences in l-T(4) needs reflect different proportions of lean mass over the total body weight. An estimate of lean mass may be helpful to shorten the time required to attain a stable dose of l-T(4), particularly in subjects with high body mass index values that may be due either to increased muscular mass or to obesity.