Monica Giannetti

Relationship between preclinical abnormalities of global and regional left ventricular function and insulin resistance in severe obesity: a Color Doppler Imaging Study

Background:The aim of this study was to evaluate the relationship between insulin resistance and preclinical abnormalities of the left ventricular structure and function detected in severe obesity by Color Doppler Myocardial Imaging (CDMI). Forty-eight consecutive severely obese patients (Group O) (11 males, 37 females, mean age 32.8±7 years) were enrolled. Forty-eight sex- and age-matched non-obese healthy subjects were also recruited as controls (Group C). All subjects underwent conventional 2D-Color Doppler echocardiography and CDMI. The homeostasis model assessment insulin resistance index (HOMA-IR) was used to assess insulin resistance results. Obese subjects had a greater left ventricular mass index (by height) (58.8±14 g/m2.7) than controls (37±8 g/m2.7) (P<0.0001), owing to compensation response to volume overload caused by a greater cardiac output (P<0.02). Preload reserve was increased in obese subjects, as demonstrated by a significant increase in left atrial dimension (P<0.0001). Obese patients had a slightly reduced LV diastolic function (transmitral E/A ratio: Group O, 1.1±0.8 vs Group C, 1.5 ±0.5; P<0.002). Cardiac deformation assessed by regional myocardial systolic strain and strain rate (SR) values was significantly lower (abnormal) in obese patients than in controls, both at the septum and lateral wall level. These strain and SR abnormalities were significantly related to body mass index. In addition, the early phase of diastolic function, evaluated using SR, was compromised in obese patients (P<0.001). The HOMA-IR values in obese patients were significantly higher (3.09±1.6) than those determined in the control group (0.92±0.5) (P<0.0001). The HOMA-IR values, in the obese group, were significantly related to systolic strain and SR values sampled at the septum level (P<0.0001).Conclusion:In conclusion, this study has demonstrated that obese patients pointed out systolic structural and functional abnormalities at a preclinical stage, in particular through strain and SR analysis; on the other hand, those altered CDMI parameters well distinguish obese subjects as compared with the control group. Furthermore, another main finding of the study was that myocardial deformation (systolic strain) could have a correlation with insulin resistance level.

Serum concentrations of adiponectin and leptin in patients with thyroid dysfunctions.

Thyroid dysfunction is associated with metabolic changes that affect mass and adipocyte function, as well as lipid and carbohydrate metabolism. Adipose tissue performs complex metabolic and endocrine functions. Leptin and adiponectin are two of the most important adipocytokines, both involved in the regulation of intermediate metabolism. The aim of this study was to evaluate the relationships between thyroid status and circulating levels of the two adipose tissue hormones. We studied 15 patients with hyperthyroidism, 15 patients with hypothyroidism and 15 euthyroid subjects, all matched by sex, age and body mass index (BMI). Serum concentrations of free thyroxine, free triiodothyronine, thyrotropin, leptin and adiponectin and anthropometric parameters (weight, height, BMI) were assessed. No significant difference was found among the 3 groups, as assessed by Student’s t-test, both for adiponectin and leptin. We conclude that metabolic changes associated with thyroid dysfunction are not related to variations in serum levels of adiponectin or leptin.

Acute exogenous TSH administration stimulates leptin secretion in vivo

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.

Effects of Bariatric Surgery on Early Myocardial Alterations in Adult Severely Obese Subjects

Objective: 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. Patients and Methods: 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. Results: 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). Conclusion: 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.

Ultrasonographic evaluation of liver volume and the metabolic syndrome in obese women

Non-alcoholic fatty liver disease is a common finding in obese subjects, and increasing evidence has been provided suggesting that it represents the hepatic component of the metabolic syndrome. The aim of this study was to evaluate whether the extent of liver enlargement is related to the severity of the metabolic syndrome in obese women. The relationship between ultrasound-measured hepatic left lobe volume (HLLV) and various features of the metabolic syndrome was evaluated in 85 obese women. The mean±SD value of HLLV in obese women was 431±214 ml (range 46–1019 ml) while it was 187±31 ml (range 143–258 ml) in lean subjects. In a multiple logistic regression analysis, ultrasound-measured intra-abdominal fat was the only anthropometric measure independently associated with HLLV. A strong positive association was found between HLLV and serum liver enzymes, triglycerides, glucose, insulin, uric acid, C reactive protein, systolic and diastolic blood pressure, while a negative correlation was observed between HLLV and HDL cholesterol. The values of HLLV corresponding to the cut-off values of various risk factors for the diagnosis of the metabolic syndrome were calculated, yielding a mean value of 465 ml. In conclusion, ultrasound measurement of HLLV represents a simple, reliable and low-cost tool for the evaluation of liver involvement in the metabolic syndrome. The strong association between liver enlargement and various cardiovascular risk factors associated with insulin resistance supports the role of liver steatosis as an important link among the many facets of the metabolic syndrome in human obesity.

Hepatic left lobe volume is a sensitive index of metabolic improvement in obese women after gastric banding

BACKGROUND:Nonalcoholic fatty liver disease is a common finding in obese subjects. Increasing evidence has been provided suggesting that it represents the hepatic component of the metabolic syndrome.OBJECTIVE:Aim of this longitudinal study was to evaluate the relationships between several anthropometric measures, including the hepatic left lobe volume (HLLV), and various indicators of the metabolic syndrome in a cohort of severely obese women before and after laparoscopic adjustable gastric banding (LAGB).STUDY DESIGN AND RESULTS:Seventy-five obese women (mean age 45±10 years and body mass index (BMI) 42.5±4.8 kg m−2) underwent LAGB and completed an average (±s.d.) post-surgical follow-up of 24±6 months. Determination of HLLV, subcutaneous and intra-abdominal fat (IAF) was based on ultrasound. The principal component statistical analysis applied to pre-operative measurements, highlighted HLLV as a parameter that clustered with serum insulin, IAF, serum glucose and uric acid, along with triglycerides (TGs), alkaline phosphatase and high-density lipoprotein cholesterol. After LAGB, the average reduction of BMI was 23%, 12% for subcutaneous fat (SCF), 42% for HLLV and 40% for visceral fat. Among body weight, BMI, SCF, IAF and HLLV, reduction of the latter was an independent predictor of reduction of serum transaminases and γ-Glutamyltransferase, glucose, insulin and TGs.CONCLUSIONS:In severely obese women: (i) HLLV is a sensitive indicator of ectopic fat deposition, clustering with parameters defining the metabolic syndrome; (ii) weight loss achieved by LAGB is associated with a reduction of liver volume as estimated by HLLV; (iii) among various anthropometric parameters measured, reduction of HLLV that follows LAGB represents the best single predictor of improvement of various cardiometabolic risk factors.

Imaging Techniques for the Measurement of Liver Volume

Assessment of liver volume may be of great relevance in the clinical management of several hepatic diseases as well as systemic disorders associated with liver involvement. With the increasing use of innovative strategies in liver resection and partial transplantation, in vivo measurement of liver volume has become of major interest. Liver volume has also been proposed as a sensitive indicator of ectopic adiposity and associated metabolic disorders in obese subjects. Several formulae have been developed for the estimation of standard liver size, based on anthropometric measures. Most data have been generated in the research areas of liver transplantation and computation of the body surface area, body weight, age, and/or gender. Several methods for measuring liver volume using Computerized Tomography (CT) or Magnetic Resonance (MR) have been described, which apply automatic or semiautomatic segmentation and subsequent reconstruction by the summation of the products of section thickness and area of the segmented liver in each section. Ultrasonography has also been employed for the estimation of liver volume. The left lateral segment of the liver can be easily visualized in its entirety by ultrasound examination, and measurement of the hepatic left lobe volume has been employed to objectively evaluate the extent of liver involvement in nonalcoholic fatty liver disease of obese subjects.

Contents Vol. 109, 2008

E. Abadie, Saint Denis C.W. Akins, Boston, Mass. J.S. Alpert, Tucson, Ariz. E.A. Amsterdam, Sacramento, Calif. J.J. Badimon, New York, N.Y. A. Battler, Petah Tikva R. Becker, Durham, N.C. G.A. Beller, Charlottesville, Va. P.C. Block, Atlanta, Ga. R.O. Bonow, Chicago, Ill. J. Camm, London B. Carabello, Houston, Tex. K. Chatterjee, San Francisco, Calif. P.F. Cohn, Stony Brook, N.Y. M.H. Crawford, San Francisco, Calif. H. Cuénoud, Worcester, Mass. J.E. Dalen, Tucson, Ariz. S. Dalla Volta, Padova P.C. Deedwania, Fresno, Calif. A.N. De Maria, San Diego, Calif. P.S. Douglas, Durham, N.C. J.A. Eleft eriades, New Haven, Conn. U. Elkayam, Los Angeles, Calif. G. Ewy, Tucson, Ariz. M. Ezekowitz, Wynnewood, Pa. R. Ferrari, Milan G. Filippatos, Athens G.I. Fishman, New York, N.Y. K. Fox, London G.S. Francis, Cleveland, Ohio V. Fuster, New York, N.Y. B.J. Gersh, Rochester, Minn. W. Gersony, New York, N.Y. J. Gold, Toledo, Ohio R. Goldberg, Worcester, Mass. S. Goldberg, Philadelphia, Pa. M. Goldman, New York, N.Y. P.J. Goldschmidt, Miami, Fla. J. Gore, Worcester, Mass. T.H. Haghfelt, Odense J.L. Halperin, New York, N.Y. C.L. Hanis, Houston, Tex. S. Haunsø, Copenhagen Z.-X. He, Beijing