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.

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.

Rapid and general profiling of protease specificity by using combinatorial fluorogenic substrate libraries

A method is presented for the preparation and use of fluorogenic peptide substrates that allows for the configuration of general substrate libraries to rapidly identify the primary and extended specificity of proteases. The substrates contain the fluorogenic leaving group 7-amino-4-carbamoylmethylcoumarin (ACC). Substrates incorporating the ACC leaving group show kinetic profiles comparable to those with the traditionally used 7-amino-4-methylcoumarin (AMC) leaving group. The bifunctional nature of ACC allows for the efficient production of single substrates and substrate libraries by using 9-fluorenylmethoxycarbonyl (Fmoc)-based solid-phase synthesis techniques. The approximately 3-fold-increased quantum yield of ACC over AMC permits reduction in enzyme and substrate concentrations. As a consequence, a greater number of substrates can be tolerated in a single assay, thus enabling an increase in the diversity space of the library. Soluble positional protease substrate libraries of 137, 180 and 6,859 members, possessing amino acid diversity at the P4-P3-P2-P1 and P4-P3-P2 positions, respectively, were constructed. Employing this screening method, we profiled the substrate specificities of a diverse array of proteases, including the serine proteases thrombin, plasmin, factor Xa, urokinase-type plasminogen activator, tissue plasminogen activator, granzyme B, trypsin, chymotrypsin, human neutrophil elastase, and the cysteine proteases papain and cruzain. The resulting profiles create a pharmacophoric portrayal of the proteases to aid in the design of selective substrates and potent inhibitors.

Effectiveness of laparoscopic sleeve gastrectomy (first stage of biliopancreatic diversion with duodenal switch) on co-morbidities in super-obese high-risk patients

BACKGROUND

We evaluated laparoscopic sleeve gastrectomy (LSG) on major co-morbidities (hypertension, type 2 diabetes / impaired glucose tolerance, obstructive sleep apnea syndrome (OSAS) and on American Society of Anesthesiologists (ASA) operative risk score in high-risk super-obese patients undergoing two-stage laparoscopic biliopancreatic diversion with duodenal switch (LBPD-DS).

METHODS

41 super-obese high-risk patients (mean BMI 57.3+/-6.5 kg/m(2), age 44.6+/-9.7 years) were entered into a prospective study (BMI > or = 60, or BMI > or = 50 with at least two severe co-morbidities, no Prader-Willi syndrome, no conversion, minimum follow-up 12 months). 9 patients had BMI > or = 60. 17 patients (41.4%) had OSAS on C-PAP therapy. In 10 patients, at least one intragastric balloon had been positioned and 4 had undergone laparoscopic adjustable gastric banding, all with unsatisfactory results. At surgery, 41.5% were classified ASA 4 and 58.5% as ASA 3 (mean ASA score 3.4+/-0.5). Patients underwent evaluation every 3 months postoperatively and were restaged at 12 months and/or before the second step.

RESULTS

60% of major co-morbidities were cured and 24% improved. Average BMI after 6 and 12 months was 44.5+/-8.1 and 40.8+/-8.5 respectively (mean follow-up 22.2+/-7.1 months). After 12 months, 57.8% of the patients were co-morbidity-free and 31.5% had only one major co-morbid condition. At restaging, 20% of patients were still classified as ASA score 4 (OSAS on C-PAP therapy). 3 patients showed BMI <30 and were co-morbidity-free 12 months after LSG.

CONCLUSIONS

LSG represents a safe and effective procedure to achieve marked weight loss as well as significant reduction of major obesity-related co-morbidities. The procedure reduced the operative risk (ASA score) in super-obese patients undergoing two-stage LBPD-DS.

Epicardial adipose tissue and insulin resistance in obese subjects

CONTEXT

Epicardial adipose tissue has been recently recognized as a source of bioactive molecules as well as free fatty acids, adiponectin, and inflammatory cytokines. Epicardial fat reflects intraabdominal visceral fat, and the echocardiographic assessment of this tissue is an easy and reliable marker of visceral adiposity.

OBJECTIVE

In this study we evaluated whether epicardial adipose tissue is related to insulin sensitivity and glucose metabolism in obese subjects.

PATIENTS

Thirty obese subjects (20 women and 10 men; mean age, 40.8 +/- 11.5 yr; body mass index, 43 +/- 9.1 kg/m2) were included in this study. No subject was taking drugs or had a history or evidence of metabolic, cardiovascular, respiratory, or hepatic disease.

MAIN OUTCOME MEASURES

Each subject underwent a transthoracic echocardiogram to evaluate epicardial adipose tissue thickness, a euglycemic hyperinsulinemic clamp to estimate insulin sensitivity, and an oral glucose tolerance test to evaluate glucose tolerance.

RESULTS

The thickness of the epicardial adipose tissue on the right ventricle varied between 4 and 17.4 mm. Echocardiographic epicardial adipose tissue was significantly correlated with whole-body glucose uptake index from the clamp and with all indices of insulin resistance and glucose intolerance measured, except the 120-min plasma glucose level after an oral glucose tolerance test.

CONCLUSIONS

Our study showed that the epicardial fat is significantly related to obesity-related insulin resistance. This finding could be of potential interest in clinical practice and research of obesity-related risk stratification.

Exercise training can modify the natural history of diabetic peripheral neuropathy

BACKGROUND

Diabetes is the most important cause of peripheral neuropathy (DPN). No definitive treatment for DPN has been established, and very few data on the role of exercise training on DPN have been reported.

AIM OF THE STUDY

We sought to examine the effects of long-term exercise training on the development of DPN in both Types 1 and 2 diabetic patients.

PARTICIPANTS AND METHODS

Seventy-eight diabetic patients without signs and symptoms of peripheral DPN were enrolled, randomized, and subdivided in two groups: 31 diabetic participants [15 f, 16 m; 49+/-15.5 years old; body mass index (BMI)=27.9+/-4.7], who performed a prescribed and supervised 4 h/week brisk walking on a treadmill at 50% to 85% of the heart rate reserve (exercise group: EXE), and a control group of 47 diabetic participants (CON; 24 f, 23 m; 52.9+/-13.4 years old; BMI=30.9+/-8.4). Vibration perception threshold (VPT), nerve distal latency (DL), nerve conduction velocity (NCV), and nerve action potential amplitude (NAPA) in the lower limbs were measured.

RESULTS

We found significant differences on Delta (delta) in NCV for both peroneal and sural motor nerve between the EXE and CON groups during the study period (P<.001, for both). The percentage of diabetic patients that developed motor neuropathy and sensory neuropathy during the 4 years of the study was significantly higher in the CON than the EXE group (17% vs. 0.0%, P<.05, and 29.8% vs. 6.45%, P<.05, respectively). In addition, the percentage of diabetic patients who developed increased VPT (25 V) during the study was significantly higher in the CON than the EXE group (21.3% vs. 12.9%, P<.05). Change on Hallux VPT from baseline to the end of the study was significantly different between the EXE and CON groups (P<.05); no significant change in Malleolus VPT between the two groups occurred.

CONCLUSIONS

This study suggests, for the first time, that long-term aerobic exercise training can prevent the onset or modify the natural history of DPN.

Effect of sustained physiologic hyperinsulinaemia and hyperglycaemia on insulin secretion and insulin sensitivity in man

Two study protocols to examine the effects of chronic (72-96 h) physiologic euglycaemic hyperinsulinaemia (+ 72 pmol/l) and chronic hyperglycaemic (+ 1.4 mmol/l) hyperinsulinaemia (+ 78 pmol/l) on insulin sensitivity and insulin secretion were performed in 15 healthy young subjects. Subjects received a three-step euglycaemic insulin (insulin infusion rates = 1.5, 3, and 6 nmol.kg-1.min-1) clamp and a hyperglycaemia (6.9 mmol/l) clamp before and after chronic insulin or glucose infusion. Following 4 days of sustained euglycaemic hyperinsulinaemia whole body glucose disposal decreased by 20-40%. During each insulin clamp step, the defect in insulin action was accounted for by impaired non-oxidative glucose disposal (p < 0.01). Chronic euglycaemic hyperinsulinaemia did not alter insulin-mediated suppression of hepatic glucose production. Following insulin infusion the ability of hyperglycaemia to stimulate insulin secretion was significantly diminished. Following 72 h of chronic glucose infusion (combined hyperglycaemic hyperinsulinaemia), there was no change in whole body glucose disposal. However, glucose oxidation during each insulin clamp step was significantly increased and there was a reciprocal decline in non-oxidative glucose disposal by 25-39% (p < 0.01); suppression of hepatic glucose production by insulin was unaltered by chronic hyperglycaemic hyperinsulinaemia. Chronic glucose infusion increased the plasma insulin response to acute hyperglycaemia more than twofold. These results demonstrate that chronic, physiologic hyperinsulinaemia, whether created by exogenous insulin infusion or by stimulation of endogenous insulin secretion, leads to the development of insulin resistance, which is characterized by a specific defect in the non-oxidative (glycogen synthetic) pathway. These findings indicate that hyperinsulinaemia should be considered, not only as a compensatory response to insulin resistance, but also as a self-perpetuating cause of the defect in insulin action.

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.

Synthesis of positional-scanning libraries of fluorogenic peptide substrates to define the extended substrate specificity of plasmin and thrombin

We have developed a strategy for the synthesis of positional-scanning synthetic combinatorial libraries (PS-SCL) that does not depend on the identity of the P1 substituent. To demonstrate the strategy, we synthesized a tetrapeptide positional library in which the P1 amino acid is held constant as a lysine and the P4-P3-P2 positions are positionally randomized. The 6,859 members of the library were synthesized on solid support with an alkane sulfonamide linker, and then displaced from the solid support by condensation with a fluorogenic 7-amino-4-methylcoumarin-derivatized lysine. This library was used to determine the extended substrate specificities of two trypsin-like enzymes, plasmin and thrombin, which are involved in the blood coagulation pathway. The optimal P4 to P2 substrate specificity for plasmin was P4-Lys/Nle (norleucine)/Val/Ile/Phe, P3-Xaa, and P2-Tyr/Phe/Trp. This cleavage sequence has recently been identified in some of plasmin's physiological substrates. The optimal P4 to P2 extended substrate sequence determined for thrombin was P4-Nle/Leu/Ile/Phe/Val, P3-Xaa, and P2-Pro, a sequence found in many of the physiological substrates of thrombin. Single-substrate kinetic analysis of plasmin and thrombin was used to validate the substrate preferences resulting from the PS-SCL. By three-dimensional structural modeling of the substrates into the active sites of plasmin and thrombin, we identified potential determinants of the defined substrate specificity. This method is amenable to the incorporation of diverse substituents at the P1 position for exploring molecular recognition elements in proteolytic enzymes.

Coumarins derivatives as dual inhibitors of acetylcholinesterase and monoamine oxidase

A set of 17 coumarin and 2 chromone derivatives with known inhibitory activity toward monoamine oxidase (MAO) A and B were tested as acetylcholinesterase (AChE) inhibitors. All compounds inhibited AChE with values in the micromolar range (3-100 microM). A kinetic study showed that most compounds acted as noncompetitive AChE inhibitors. This finding may be of interest in the context of Alzheimer's disease because recent observations suggest that MAO and AChE inhibition might decrease beta-amyloid deposition.

Inhibition of monoamine oxidases by functionalized coumarin derivatives: biological activities, QSARs, and 3D-QSARs

A large series of coumarin derivatives (71 compounds) were tested for their monoamine oxidase A and B (MAO-A and MAO-B) inhibitory activity. Most of the compounds acted preferentially on MAO-B with IC(50) values in the micromolar to low-nanomolar range; high inhibitory activities toward MAO-A were also measured for sulfonic acid esters. The most active compound was 7-[(3, 4-difluorobenzyl)oxy]-3,4-dimethylcoumarin, with an IC(50) value toward MAO-B of 1.14 nM. A QSAR study of 7-X-benzyloxy meta-substituted 3,4-dimethylcoumarin derivatives acting on MAO-B yielded good statistical results (q(2)() = 0.72, r(2)() = 0.86), revealing the importance of lipophilic interactions in modulating the inhibition and excluding any dependence on electronic properties. CoMFA was performed on two data sets of MAO-A and MAO-B inhibitors. The GOLPE procedure, with variable selection criteria, was applied to improve the predictivity of the models and to facilitate the graphical interpretation of results.

Long-term effects of laparoscopic sleeve gastrectomy, gastric bypass, and adjustable gastric banding on type 2 diabetes

BACKGROUND

This study aimed to compare the efficacy of laparoscopic sleeve gastrectomy (SG) with that of laparoscopic gastric bypass (GBP) and laparoscopic adjustable gastric banding (AGB) for glucose homeostasis in morbidly obese subjects with type 2 diabetes mellitus (T2DM) at a 3-year follow-up assessment and to elucidate the role of weight loss in the T2DM resolution after SG.

METHODS

For this study, 60 morbidly obese T2DM patients (44 females and 16 males) who underwent AGB (24 patients), GBP (16 patients), or SG (20 patients) between 1996 and 2008 were retrospectively analyzed. Age, sex, body mass index (BMI), estimated weight loss (EWL), fasting glycemia, HbA1c, euglycemic hyperinsulinemic clamp, discontinuation of diabetes treatment, and time until interruption of therapy were evaluated.

RESULTS

In the study, 54 patients received oral hypoglycemic agents for at least 12 months before surgery, and 6 patients received insulin. The mean follow-up period was 36 months. The resolution rate was 60.8% for the AGB patients, 81.2% for the GBP patients, and 80.9% for the SG patients. The postoperative time until interruption of therapy was 12.6 months for the AGB patients, 3.2 months for the GBP patients, and 3.3 months for the SG patients. The hyperinsulinemic euglycemic clamp test was performed 12 months after surgery for the cured patients. Insulin resistance was restored to normal values in all the patients. The greatest improvement from preoperative values occurred in the SG group. For the not-cured GBP and SG patients, an improvement of 120 mg/dl in fasting plasma glucose was observed 3 months after the surgery, suggesting an enhancement in insulin sensitivity, which determines better medical control. The resolution rate remained constant at the 36-month follow-up evaluation in both the GBP and SG groups.

CONCLUSIONS

All three bariatric procedures are effective in treating diabetes, with a 3-year follow-up evaluation showing an effect that lasts. The AGB procedure was the least effective. The antidiabetic effect was similarly precocious after GBP and SG compared with AGB. This difference may indicate that a hormonal mechanism may be involved, independent of weight loss.

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.

Liver vitamin D receptor, CYP2R1, and CYP27A1 expression: relationship with liver histology and vitamin D3 levels in patients with nonalcoholic steatohepatitis or hepatitis C virus

Evidence suggests an association between low serum 25-hydroxy-vitamin D(3) [25(OH)D(3) ] levels and the presence and prognosis of liver disease. Vitamin D receptor (VDR) has been widely detected in the liver, but its expression in the course of liver disease has never been investigated. We evaluated the hepatic expression of VDR along with that of vitamin D 25-hydroxylases in patients with nonalcoholic steatohepatitis (NASH) or chronic hepatitis C (CHC) and its relationship with hepatic histological features and serum 25(OH)D(3) levels. We evaluated 61 patients (25 NASH and 36 CHC) who had undergone liver biopsy for clinical purposes and 20 subjects without liver disease. Serum 25(OH)D(3) was measured via colorimetric assay. Expression of VDR, CYP2R1, and CYP27A1 was evaluated via immunohistochemistry in hepatocytes, cholangiocytes, and liver inflammatory cells. Parenchymal and inflammatory cells from liver biopsies of patients with NASH and CHC expressed VDR, CYP2R1, and CYP27A1. In NASH patients, VDR expression on cholangiocytes was inversely correlated with steatosis severity (P < 0.02), lobular inflammation (P < 0.01), and nonalcoholic fatty liver disease score (P < 0.03). Moreover, expression of CYP2R1 in hepatocytes correlated strongly with VDR positivity on liver inflammatory cells. In CHC subjects, fibrosis stage was associated with low hepatic CYP27A1 expression, whereas portal inflammation was significantly higher in patients with VDR-negative inflammatory cells (P < 0.009) and low VDR expression in hepatocytes (P < 0.03).

CONCLUSION

VDR is widely expressed in the liver and inflammatory cells of chronic liver disease patients and its expression is negatively associated with the severity of liver histology in both NASH and CHC patients. These data suggest that vitamin D/VDR system may play a role in the progression of metabolic and viral chronic liver damage. (HEPATOLOGY 2012;56:2180-2187).

Relationship of epicardial adipose tissue with atrial dimensions and diastolic function in morbidly obese subjects

Obesity is associated with atrial dilation and diastolic dysfunction although the causative mechanisms are not completely understood. In this study we showed for the first time that increase in epicardial fat thickness is significantly correlated with atria enlargement and impairment in diastolic filling in morbidly obese subjects.

Continuous subcutaneous glucose monitoring in diabetic patients: a multicenter analysis

OBJECTIVE

To evaluate the accuracy of a new subcutaneous glucose sensor (Glucoday; A. Menarini Diagnostics) compared with venous blood glucose measurement in type 1 and type 2 diabetic patients.

RESEARCH DESIGN

A multicenter study was performed in 70 diabetic patients. A microdialysis fiber was inserted subcutaneously into the periumbelical region and perfused with a buffer solution. Glucose concentrations in the dialysate were then measured every 3 min by the glucose sensor over a 24-h period, during which nine venous blood samples were also collected throughout the day.

RESULTS

Both the insertion of the fiber and the wearing of the device were well tolerated by the patients. Subcutaneous glucose levels were well correlated with venous glucose measurements (r = 0.9, P < 0.001) over a wide range (40-400 mg/dl) for up to 24 h, with a single-point calibration. An analysis of 381 data pairs showed a linear relationship between the GlucoDay and serial venous blood glucose levels, and 97% of the data fell in the A and B regions of the error grid analysis. Percentage bias between the GlucoDay and the blood venous levels was -2.0% in the hypoglycemic range (<70 mg/dl), 6.9% in the euglycemic range (70-180 mg/dl), and 11.2% in the hyperglycemic range (>180 mg/dl).

CONCLUSIONS

The GlucoDay system demonstrated high reliability and reported values that closely agreed with venous blood glucose measurements. The system was well tolerated and thus constitutes a relatively easy method to monitor glucose excursions in diabetic patients.

Adiponectin expression in human epicardial adipose tissue in vivo is lower in patients with coronary artery disease

BACKGROUND

Intra-peritoneal adipose tissue is recognized as a predictor of metabolic syndrome and may contribute to the risk for cardiovascular disease by the production of adipocytokines, including adiponectin. Nevertheless, there is no knowledge on whether other visceral depots of adipose tissue, including the epicardial fat, have any metabolically active role, including production of adiponectin.

AIM OF THE STUDY

We sought to evaluate adiponectin protein expression in epicardial adipose tissue in vivo both in patients with severe coronary artery disease (CAD) and in subjects without CAD.

METHODS

Twenty-two patients were enrolled for the study. We selected 16 patients who underwent elective coronary artery bypass graft surgery for critical CAD, 5 who underwent surgery for valve replacement and 1 for correction of an interatrial defect. Epicardial adipose tissue biopsy samples were obtained before the initiation of cardiopulmonary bypass. Adiponectin protein level in epicardial adipose tissue was evaluated by Western blotting.

RESULTS

Adiponectin protein value, expressed as adiponectin/actin ratio, in epicardial adipose tissue was significantly lower in patients with severe CAD than in those without CAD (1.42 +/- 0.77 vs 2.36 +/- 0.84 p = 0.02, 95% CI 0.64-1.74).

CONCLUSIONS

This study showed for the first time that human epicardial adipose tissue expresses adiponectin. Adiponectin expression is significantly lower in epicardial fat isolated from patients with CAD.

Morbid obesity exposes the association between PNPLA3 I148M (rs738409) and indices of hepatic injury in individuals of European descent

CONTEXT

The PNPLA3 I148M variant (rs738409) is robustly associated with hepatic steatosis. Intriguingly, initial findings in cohorts with a mean body mass index (BMI) of 30 kg m(-2) also suggested that it is associated with elevated liver enzymes but not with insulin resistance and dyslipidaemia.

OBJECTIVE

To determine whether the PNPLA3 variant alters the susceptibility of morbidly obese subjects to develop liver injury and metabolic sequelae.

PARTICIPANTS AND METHODS

The study was carried out in 678 obese Italians (mean BMI = 41 kg m(-2)) who were genotyped for the I148M variant. All participants provided fasting blood samples and then underwent oral glucose tolerance tests.

MAIN OUTCOME MEASURES

Indices of liver injury (alanine transaminase (ALT), aspartate transaminase (AST)), glucose tolerance and insulin resistance were measured.

RESULTS

Markers of hepatic injury such as ALT and AST were significantly higher in carriers of the 148M allele (P = 2.2 x 10(-5) and 0.001, respectively). In all, 50% of 148M risk allele homozygotes had pathological levels of ALT (>40 U l(-1)) compared with 25% of 148I allele homozygotes (P = 0.005). Glucose tolerance and insulin sensitivity were similar in all three genotypes.

CONCLUSION

Obese Southern Europeans carrying the 148M allele have increased indices of liver damage uncoupled from proxy measures of insulin resistance.

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.

Gut Microbiota Markers in Obese Adolescent and Adult Patients: Age-Dependent Differential Patterns

Obesity levels, especially in children, have dramatically increased over the last few decades. Recently, several studies highlighted the involvement of gut microbiota in the pathophysiology of obesity. We investigated the composition of gut microbiota in obese adolescents and adults compared to age-matched normal weight (NW) volunteers in order to assemble age- and obesity-related microbiota profiles. The composition of gut microbiota was analyzed by 16S rRNA-based metagenomics. Ecological representations of microbial communities were computed, and univariate, multivariate, and correlation analyses performed on bacterial profiles. The prediction of metagenome functional content from 16S rRNA gene surveys was carried out. Ecological analyses revealed a dissimilarity among the subgroups, and resultant microbiota profiles differed between obese adolescents and adults. Using statistical analyses, we assigned, as microbial markers, Faecalibacterium prausnitzii and Actinomyces to the microbiota of obese adolescents, and Parabacteroides, Rikenellaceae, Bacteroides caccae, Barnesiellaceae, and Oscillospira to the microbiota of NW adolescents. The predicted metabolic profiles resulted different in adolescent groups. Particularly, biosynthesis of primary bile acid and steroid acids, metabolism of fructose, mannose, galactose, butanoate, and pentose phosphate and glycolysis/gluconeogenesis were for the majority associated to obese, while biosynthesis and metabolism of glycan, biosynthesis of secondary bile acid, metabolism of steroid hormone and lipoic acid were associated to NW adolescents. Our study revealed unique features of gut microbiota in terms of ecological patterns, microbial composition and metabolism in obese patients. The assignment of novel obesity bacterial markers may open avenues for the development of patient-tailored treatments dependent on age-related microbiota profiles.

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.

Timing of nephrology referral: influence on mortality and morbidity

To assess the influence of the timing of nephrology referral on the short- and long-term outcome of hemodialysis patients, we retrospectively studied 309 patients who had end-stage renal failure and entered the chronic hemodialysis program in Sainte-Marguerite University Hospital between January 1, 1989, and December 31, 1996. We excluded from the analysis five patients without available data on referral pattern and 34 patients with irreversible acute renal failure. Of the remaining 270 patients, 177 patients (58%) had an early referral (ER) 16 or more weeks before the start of dialysis, and 93 patients (31%) had a late referral (LR) of less than 16 weeks before dialysis. Short-time morbidity (initial emergent dialysis, pulmonary edema, severe hypertension, temporary vascular access placement for first dialysis, prolonged initial hospitalization) was significantly more frequent in LR patients. Long-term evolution (mean follow-up, 26.5 +/- 26 months) did not differ between the two groups. The number of days of hospitalization per patient-year at risk beyond the third month was 21.5 +/- 33.7 days for ER and 21.1 +/- 36 days for LR patients. Survival analysis showed no difference between the two groups: 3-month survival rates were 96% in both groups, 1-year survival rates were 90% in the ER and 89% in the LR group, and 5-year survival rates were 52% in the ER and 56% in the LR group. In a Cox hazards regression model, referral pattern was not associated with a greater risk for death. In conclusion, delayed nephrology referral generated strikingly greater initial morbidity, but long-term outcome of hemodialysis patients was not modified by delayed nephrological care.

Association of the human adiponectin gene and insulin resistance

Adiponectin is an adipocyte-secreted protein that modulates insulin sensitivity and whose low circulating concentration is associated with insulin resistance. In the present study, we analysed the association between two single-nucleotide polymorphisms (SNPs) in the adiponectin gene and insulin resistance in 253 nondiabetic subjects. In addition, we investigated whether this association is modulated by body mass index (BMI) levels. The SNPs +45T>G and +276G>T in the human adiponectin gene were detected in real-time PCR with LightCycler. No association was found with the +45T>G SNP. The +276G>T SNP was associated with higher BMI (P<0.01), plasma insulin (P<0.02) and HOMA(IR) (P<0.02). To analyse the possible interaction between BMI and the adiponectin gene on insulin resistance, the study group was divided into two subgroups, according to the BMI below or above the median of 26.2 kg/m(2). In both subgroups, subjects carrying the +276G>T SNP had higher HOMA(IR); however, the difference was highly significant among leaner (P<0.001), but not among heavier individuals, indicating that BMI status and the adiponectin gene interact in modulating insulin resistance. Among individuals with BMI <26.2 kg/m(2), the relative risk of insulin resistance was 9.7 (CI: 1.32-87.7, P<0.035). In a subgroup of 67 subjects, carriers of the +276G>T SNP had significantly (P<0.05) lower mean serum adiponectin levels (25.7 ng/ml) compared to noncarriers (37.0 ng/ml), suggesting a possible influence of the +276G>T SNP on adiponectin levels. In summary, we observed an association between the +276G>T SNP in the adiponectin gene and insulin resistance. In particular, among leaner individuals, the adiponectin gene appears to determine an increased risk to develop insulin resistance.

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.

First-phase insulin secretion, insulin sensitivity, ghrelin, GLP-1, and PYY changes 72 h after sleeve gastrectomy in obese diabetic patients: the gastric hypothesis

BACKGROUND

The aim of this study was to evaluate the possible role of sleeve gastrectomy (SG) per se in the reversibility of diabetes.

METHODS

Insulin secretion and peripheral insulin sensitivity using the intravenous glucose tolerance test (IVGTT) were assessed in 18 obese type 2 diabetic patients and in 10 nondiabetic obese patients before and 3 days after SG, before any food intake and any weight change occurrence. At the same time, ghrelin, GLP-1, and PYY levels were determined.

RESULTS

In diabetic patients who had the disease less than 10.5 years, the first phase of insulin secretion promptly improved after SG. The early insulin area under the curve (AUC) significantly increased at the postoperative IVGTT, indicating an increased glucose-induced insulin secretion. The second phase of insulin secretion (late AUC) significantly decreased after SG in all groups, indicating an improved insulin peripheral sensitivity. In all groups, pre- and postoperatively, intravenous glucose stimulation determined a decrease in ghrelin values and an increase in GLP-1 and PYY values. However, in the group of patients with disease duration >10.5 years, the differences were not significant except for the late insulin AUC. Postoperative basal and intravenous glucose-stimulated ghrelin levels were lower than preoperative levels in all groups of patients. Basal and intravenous stimulated GLP-1 and PYY postoperative values were higher than preoperative levels in all groups.

CONCLUSIONS

Restoration of the first phase of insulin secretion and improved insulin sensitivity in diabetic obese patients immediately after SG, before any food passage through the gastrointestinal tract and before any weight loss, seem to be related to ghrelin, GLP-1, and PYY hormonal changes of possible gastric origin and was neither meal- nor weight-change-related. Duration of the disease up to 10.5 years seems to be a major cut off in the pathophysiological changes induced by SG. A "gastric" hypothesis may be put forward to explain the antidiabetes effect of SG.