Metformin maintains the weight loss and metabolic benefits following rimonabant treatment in obese women with polycystic ovary syndrome (PCOS)

Objective Rimonabant has been shown to reduce weight, free androgen index (FAI) and insulin resistance in obese patients with polycystic ovary syndrome (PCOS) compared to metformin. Studies have shown that significant weight regain occurs following the cessation of rimonabant therapy. This study was undertaken to determine if subsequent metformin treatment after rimonabant would maintain the improvement in weight, insulin resistance and hyperandrogenaemia in PCOS. Design An extension study for 3 months with the addition of metformin to the randomised open labelled parallel study of metformin and rimonabant in 20 patients with PCOS with a body mass index ≥ 30 kg/m². Patients who were on 3 months of rimonabant were changed over to metformin for 3 months, whereas those on 3 months of metformin were continued on metformin for another 3 months. Measurements The primary end‐point was a change in weight; secondary end‐points were a change in FAI and insulin resistance. Results The mean weight loss of 6·2 kg associated with 3 months of rimonabant treatment was maintained by 3 months of metformin treatment (mean change +0·2 kg, P = 0·96). Therefore, the percentage reduction in weight remained significantly higher in the rimonabant/metformin group compared to metformin only subjects at 6 months compared to baseline (–6·0 ± 0·1%vs. –2·8 ± 0·1%, P = 0·04). The percentage change in testosterone and FAI from baseline to 6 months was also greater in the rimonabant/metformin group. [Testosterone (–45·0 ± 5·0%vs. –16 ± 2·0%, P = 0·02); FAI (–53·0 ± 5·0%vs. –17·0 ± 12·2%, P = 0·02)]. HOMA‐IR continued to fall significantly in the rimonabant/metformin group between 0, 3 and 6 months (4·4 ± 0·5 vs. 3·4 ± 0·4 vs. 2·7 ± 0·3, respectively, P < 0·01) but not at all in the metformin only group (3·4 ± 0·7 vs. 3·4 ± 0·8 vs. 3·7 ± 0·8, respectively, P = 0·80). Total cholesterol and LDL reduced significantly in both groups, but improvements in triglycerides and HDL were limited to the rimonabant/metformin group. Conclusions In these obese patients with PCOS, metformin maintained the weight loss and enhanced the metabolic and biochemical parameters achieved by treatment with rimonabant, compared to 6 months of metformin treatment alone.     

Altered distribution of adiponectin isoforms in children with Prader-Willi syndrome (PWS): association with insulin sensitivity and circulating satiety peptide hormones

Objective Prader–Willi syndrome (PWS) is a genetic syndrome characterized by relative hypoinsulinaemia and normal or increased insulin sensitivity despite profound obesity. We hypothesized that this increased insulin sensitivity is mediated by increased levels of total and high molecular weight adiponectin and associated with changes in levels of satiety hormones. Design, patients and measurements We measured total adiponectin and its isoforms [high molecular weight (HMW), middle molecular weight (MMW) and low molecular weight (LMW) adiponectin] and satiety hormones in 14 children with PWS [median age 11·35 years, body mass index (BMI) Z‐score 2·15] and 14 BMI‐matched controls (median age 11·97 years, BMI Z‐score 2·34). Results Despite comparable BMI Z‐scores and leptin levels, the PWS children exhibited lower fasting insulin and HOMA‐IR (homeostasis model assessment of insulin resistance) scores compared to obese controls. For any given BMI Z‐score, the PWS children showed higher concentrations of fasting total and HMW adiponectin and higher HMW/total adiponectin ratios. The HMW/total adioponectin ratio was preserved in children with PWS at high degrees of obesity. In PWS children, fasting plasma total adiponectin, HMW adiponectin and HMW/total adiponectin ratio correlated negatively with age (P < 0·05), HOMA‐IR (P < 0·01), BMI Z‐score (P < 0·05), insulin (P < 0·01) and leptin (P < 0·05). In addition to higher fasting ghrelin concentrations, the PWS children showed significantly higher fasting levels of total peptide YY (PYY) and gastric inhibitory polypeptide (GIP) compared to obese controls. Conclusions Relative to controls of similar age and BMI Z‐score, the PWS children had significantly higher levels of total and HMW adiponectin, and increased ratios of HMW/total adiponectin. These findings may explain in part the heightened insulin sensitivity of PWS children relative to BMI‐matched controls.     

Alteration of ghrelin-neuropeptide Y network in obese patients with polycystic ovary syndrome: role of hyperinsulinism

Objective Insulin, ghrelin, neuropeptide Y (NPY) and leptin interact in the regulation of energy homeostasis. Most of these signals are altered in polycystic ovary syndrome (PCOS), which is characterized by a high prevalence of obesity. The present study was conducted to evaluate ghrelin–NPY and ghrelin–leptin interplays in relation to insulin secretion in obese PCOS subjects. Design Pilot prospective study. Patients Seven obese PCOS women and seven age–weight matched controls. Measurements Hormonal measurements, oral glucose tolerance test (OGTT) and a ghrelin test (1 µg/kg i.v. bolus). PCOS patients repeated the clinical work‐up after 4 months of metformin treatment (1500 mg/day orally). Results At baseline, PCOS women showed a significantly higher insulinaemic response to the OGTT compared to controls (P < 0·05). In basal conditions, PCOS women exhibited lower NPY levels than controls (P < 0·01). Ghrelin injection markedly increased NPY in controls (P < 0·01), whereas PCOS women showed a deeply blunted NPY response to the stimulus (area under the curve – AUC–NPY: P < 0·01 vs. controls.). Metformin treatment induced a significant decrease in insulin levels (P < 0·01) and the concomitant recovery of NPY secretory capacity in response to ghrelin (AUC–NPY: P < 0·05 vs. baseline) in PCOS women. Leptin levels, which were similar in the two groups, were not modified by ghrelin injection; metformin did not affect this pattern. Conclusion Hyperinsulinaemia seems to play a pivotal role in the alteration of NPY response to ghrelin in obese PCOS women. This derangement could be implicated in the physiopatology of obesity in these patients.     

Total and high molecular weight (HMW) adiponectin levels and measures of glucose and lipid metabolism following pioglitazone treatment in a randomized placebo-controlled study in polycystic ovary syndrome

Objective Recent studies suggested that the effect of adiponectin on insulin‐stimulated glucose metabolism is mediated primarily by the high molecular weight (HMW) form of adiponectin. In the present study we evaluated total and HMW adiponectin in polycystic ovary syndrome (PCOS) patients and controls and examined possible mechanisms for increased insulin sensitivity during pioglitazone treatment. Study subjects Thirty PCOS patients randomized to pioglitazone, 30 mg/day, or placebo for 16 weeks and 14 weight‐matched healthy females were studied. Design Total and HMW adiponectin levels were measured, and euglycaemic hyperinsulinaemic clamps and indirect calorimetry were performed. Δ‐values denoted changes during pioglitazone treatment (16 weeks – basal). Results Pretreatment adiponectin levels were decreased in PCOS patients vs. controls (P < 0·05), whereas no significant differences were found in HMW adiponectin levels. Following pioglitazone treatment, total and HMW adiponectin increased (all P < 0·05), whereas no significant changes were observed with placebo. Δ‐total adiponectin levels correlated positively with the rate of Δ‐insulin‐stimulated glucose disposal (R_d) (r = 0·89) and Δ‐oxidative glucose metabolism (r = 0·71) and inversely with Δ‐fasting free fatty acid (FFA) levels (r = –0·69) and Δ‐lipid oxidation (r = –0·73) during insulin stimulation (all P < 0·01). Weaker correlations were found between Δ‐HMW adiponectin levels and Δ‐measures of glucose and lipid metabolism during insulin stimulation than with Δ‐total adiponectin. Conclusion A close correlation between increased total adiponectin levels and increased insulin‐stimulated glucose metabolism during pioglitzone treatment supports the hypothesis that the insulin‐sensitizing effect of pioglitazone in PCOS is, at least in part, mediated by adiponectin. Measures of changes in HMW adiponectin did not add further information to this relationship.     

Retinol-binding protein in nonobese women with polycystic ovary syndrome

Objective Although polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance, cardiovascular disease and various metabolic diseases, the mechanisms linking PCOS to metabolic changes are not fully understood. Retinol‐binding protein (RBP) was recently reported as an adipocytokine that may link insulin resistance and lipid metabolism. The aim of this study was to investigate the potential role of RBP in women with PCOS. Research design and methods Fifty women with PCOS and 40 healthy women, all of whom were age‐ and weight‐matched, were studied. Blood was obtained to determine RBP levels as well as metabolic and hormonal parameters, and the homeostasis model assessment of insulin resistance (HOMA‐IR) was calculated for each subject. Results The RBP levels were higher (P < 0·01) in women with PCOS after adjusting for age, body mass index (BMI), mean blood pressure, triglyceride (TG), high density lipoprotein (HDL)‐cholesterol, low density lipoprotein (LDL)‐cholesterol, fasting glucose, fasting insulin, estimated glomerular filtration rate (GFR), LH/FSH, total testosterone and SHBG levels. PCOS status was the strongest predictor of elevated RBP levels. In both the PCOS and control groups, RBP levels were significantly correlated with HOMA‐IR (P = 0·03 in the PCOS group; P = 0·01 in controls). In addition, RBP levels were significantly correlated with total cholesterol, LDL‐cholesterol and TG levels in PCOS (P < 0·01, P < 0·01 and P = 0·01, respectively). Conclusions Higher RBP levels in the PCOS group, when compared to the non‐PCOS group, were observed, and this difference may play a role in the pathophysiology found in women with PCOS. Further studies are needed to clarify the role of RBP in these women.     

Obestatin and ghrelin levels in obese children and adolescents before and after reduction of overweight

Objectives Obestatin and ghrelin, which are derived from the same gene, are observed to have opposite effects on weight status. The aims of this study were to compare obestatin concentrations in obese and normal‐weight children and to analyse the effect of weight loss on obestatin and ghrelin levels. Methods We examined anthropometrical markers and fasting serum obestatin, ghrelin, leptin, glucose and insulin concentrations in 44 obese children (mean age 11·2 years) before and after participating in a 1‐year outpatient obesity intervention programme based on a high‐carbohydrate, fat‐reduced diet and increased physical activity. Additionally, total ghrelin, obestatin and leptin levels were determined in 22 normal‐weight healthy children of similar age, gender and pubertal stage. Results Obestatin and leptin concentrations were significantly (P < 0·001) higher and ghrelin concentrations were significantly (P < 0·001) lower in obese children compared to nonobese children. In contrast to the 13 children without weight loss, substantial weight loss in 31 children led to a significant (P = 0·007) increase in obestatin and to a significant (P < 0·05) decrease in leptin and insulin concentrations, while ghrelin concentrations did not change significantly. Children with substantial weight loss demonstrated significantly (P = 0·009) lower obestatin and a tendency (P = 0·064) to higher ghrelin concentrations at baseline. Changes in insulin were not related to changes in ghrelin or obestatin. Conclusion The increase in obestatin and the decrease in ghrelin in obese children point towards an adaptation process of weight status. Weight reduction due to a long‐term lifestyle intervention resulted in an increase in obestatin levels.     

Clomiphene citrate, metformin or both as first-step approach in treating anovulatory infertility in patients with polycystic ovary syndrome (PCOS): a systematic review of head-to-head randomized controlled studies and meta-analysis

Background To date, no systematic review or meta‐analysis has been published of direct head‐to‐head studies comparing clomiphene citrate (CC) vs. metformin, or the combination of both drugs as first‐line therapy in anovulatory polycystic ovary syndrome (PCOS) patients seeking pregnancy. The aim of the current paper was to define, if possible, the best evidence‐based recommendations regarding the use of CC and/or metformin as the initial treatment of PCOS women with anovulatory infertility. Design Systematic review and meta‐analysis of the head‐to‐head randomized controlled trials (RCTs) available in the literature. Methods A bibliographic search was performed using the following bibliographic databases: Medline, EMBASE, Biological Abstracts, Cochrane Controlled Trials Register and Cochrane Database of Systematic Reviews. Reference lists of included studies, other relevant review articles and textbooks were checked for additional citations of interest. Results Four head‐to‐head RCTs were identified and qualified for inclusion in the analysis. No difference in fertility improvement was observed comparing CC with metformin (OR = 1·22, 95% CI 0·23–6·55, P = 0·815), whereas a significant (P < 0·0001) heterogeneity was observed. Homogeneous data showed no difference in fertility improvement between the combination treatment and CC monotherapy (OR = 0·99, 95% CI 0·70–1·40, P = 0·982), but a significant difference in comparison with metformin monotherapy (OR = 0·23, 95% CI 0·14–0·37, P < 0·0001). Conclusions In PCOS patients with anovulatory infertility and not previously treated, the administration of metformin plus CC is not better than monotherapy (metformin alone or CC alone), whereas to date no specific recommendation can be given regarding the use of CC or metformin as first‐step drug.     

A comparison between rimonabant and metformin in reducing biochemical hyperandrogenaemia and insulin resistance in patients with polycystic ovary syndrome (PCOS): a randomized open-label parallel study

Context Weight loss and metformin therapy are reported to be beneficial in improving the biochemical hyperandrogenaemia and insulin resistance of polycystic ovary syndrome (PCOS). Rimonabant has been found to reduce weight and improve the metabolic profile in patients with obesity, type 2 diabetes and metabolic syndrome. Objective To compare the effects of insulin sensitization with metformin to weight reduction by rimonabant on biochemical hyperandrogenaemia and insulin resistance in patients with PCOS. Design A randomized, open‐label parallel study. Setting Endocrinology outpatient clinic in a referral centre. Subjects Twenty patients with PCOS and biochemical hyperandrogenaemia with a body mass index (BMI) ≥ 30 kg/m² were recruited. Intervention Patients were randomized to 1·5 g daily of metformin or 20 mg daily of rimonabant. Main outcome measures The primary end‐point of the study was a change in total testosterone. Results After 12 weeks of rimonabant there was a significant reduction (mean ± SEM) in weight (104·6 ± 4·6 vs. 98·4 ± 4·7 kg, P < 0·01), waist circumference (116·0 ± 3·3 vs. 109·2 ± 3·7 cm, P < 0·01), hip circumference (128·5 ± 4·0 vs. 124·1 ± 4·2 cm, P < 0·03), waist–hip ratio (0·90 ± 0·02 vs. 0·88 ± 0·01, P < 0·01) free androgen index (FAI) (26·6 ± 6·1 vs. 16·6 ± 4·1, P < 0·01), testosterone [4·6 ± 0·4 vs. 3·1 ± 0·3 nmol/l (132·7 ± 11·5 vs. 89·4 ± 8·65 ng/dl), P < 0·01] and insulin resistance as measured by the homeostasis model assessment (HOMA) method (4·4 ± 0·5 vs. 3·4 ± 0·4, P = 0·05). There was no change in any of these parameters in the metformin‐treated group. Conclusion This study suggests that the weight loss through rimonabant therapy may be of use in patients with PCOS and appears superior to insulin sensitization by metformin in reducing the FAI and insulin resistance in obese PCOS patients treated over a 12‐week period.     

Exercise training improves autonomic function and inflammatory pattern in women with polycystic ovary syndrome (PCOS)

Background Polycystic ovary syndrome (PCOS) is a common female reproductive‐age endocrine disease predominantly characterized by chronic anovulation, hyperandrogenism, insulin‐resistance and low‐grade inflammatory status. Exercise training (ET) favourably modulates cardiopulmonary function and insulin‐sensitivity markers in PCOS women. The present study investigated the effects of ET on autonomic function and inflammatory pattern in PCOS women. Study design Prospective baseline uncontrolled clinical study. Methods One‐hundred and eighty five PCOS women referred to our department were screened for the inclusion into the study protocol from March 2004 to July 2007. One‐hundred and twenty four PCOS women met the criteria for the inclusion into the study protocol and were subdivided into two groups each composed of 62 patients: PCOS‐T (trained) group underwent 3‐month ET program, whereas PCOS‐UnT (untrained) group did not. At baseline and at 3‐month follow‐up, hormonal and metabolic profile, cardiopulmonary parameters, autonomic function (as expressed by heart rate recovery, HRR) and inflammatory pattern [as expressed by C‐reactive protein (CRP) and white blood cells (WBCs) count] were evaluated. Results PCOS‐T showed a significant (P < 0·05) improvement in maximal oxygen consumption (VO_2max) and in post‐exercise HRR, and a significant (P < 0·001) decrease in CRP and WBCs; whereas no statistically significant changes of the same parameters were observed in PCOS‐UnT. Multiple linear regression analysis showed that 3‐month HRR is linearly related to the inclusion in training group (β = 0·316, P < 0·001), VO_2max (β = 0·151, P = 0·032) and the ratio between glucose and insulin area under curve (AUC) (β = 0·207, P = 0·003), and inversely related to body mass index (β = –0·146, P = 0·046), insulin AUC (β = –0·152, P = 0·032), CRP (β = –0·165, P < 0·021), and WBCs count (β = –0·175, P = 0·039). Conclusions Exercise training improves autonomic function and inflammatory pattern in PCOS women.     

Metabolic and cardiopulmonary effects of detraining after a structured exercise training programme in young PCOS women

Objective The aim of the present study was to determine if the favourable cardiopulmonary and metabolic benefits induced by exercise training (ET) programme are maintained after its cessation. Patients Thirty‐two young overweight polycystic ovary syndrome (PCOS) women matched for age and body mass index (BMI) with other 32 PCOS patients was enrolled. The first group [PCOS‐T (trained)] underwent 24‐week ET programme, whereas the second [PCOS‐DT (detrained)] underwent 12‐week ET programme followed by 12‐week detraining period. Methods At baseline, after 12‐ and 24‐week follow‐up, all PCOS women were studied for their hormonal (ovarian and adrenal androgens), metabolic (glucose and insulin) and lipid profile, and underwent cardiopulmonary exercise test. Results After the initial 12‐week ET programme, both PCOS‐T and PCOS‐DT groups, without differences between groups, showed a similar significant (P < 0·05) improvement in BMI, fasting insulin, areas under curve insulin (AUC_INS), glucose and insulin AUC (AUC_GLU/INS), high‐density lipoprotein‐cholesterol (HDL‐C), low‐density lipoprotein‐cholesterol (LDL‐C) and maximal oxygen consumption at cardiopulmonary exercise test (VO_2max). At 24‐week follow‐up, PCOS‐T group showed a significant (P < 0·05) improvement in BMI, fasting insulin, AUC_INS, AUC_GLU/INS, LDL‐C, HDL‐C and VO_2max, in comparison to baseline and 12‐week follow‐up. At same follow‐up visit, the all parameters resulted significantly (P < 0·05) worsened in PCOS‐DT group in comparison to 12‐week follow‐up and PCOS‐T group. In PCOS‐DT group, no parameter assessed at 24‐week follow‐up was significantly different in comparison with baseline. Conclusion In young PCOS women, 12‐week detraining resulted in a complete loss of the favourable adaptations obtained after ET.     

Visfatin, low-grade inflammation and body mass index (BMI)

Objective Visfatin is an adipokine with revealing roles in inflammatory mechanisms but its implication in inflammation related to excessive adiposity/obesity is not studied yet. Our aim was to investigate the relations of visfatin with inflammation markers and body mass index (BMI) in the peripheral blood mononuclear cells (PBMCs), a type of cells closely related to inflammatory mechanisms. Design Cross‐sectional study, quantification of visfatin, TNF‐α, IL‐6 mRNA in PBMCs. Patients Eighty‐three supposed healthy individuals from the STANISLAS cohort, belonging in three BMI categories: BMI < 25 kg/m² (lean), 25 kg/m² ≤ BMI < 30 kg/m² (overweight) or BMI ≥ 30 kg/m² (obese). Measurements We measured visfatin gene expression (by real‐time quantitative PCR), in relation to gene expression of the pro‐inflammatory cytokines TNF‐α, IL‐6 in PBMCs and to anthropometric parameters (weight, BMI, waist : hip ratio), blood pressure, lipid profile, glucose and inflammatory markers (C‐reactive protein, lymphocyte count). Results Visfatin expression in PBMCs was significantly associated with BMI in a negative way (r = –0·21, P = 0·05). Global anova analysis test for lean and over‐weight/obese individuals showed a negative significant association between visfatin expression in PBMCs and BMI both for men and women (P = 0·05 and P = 0·01, respectively) and these associations remained significant after separating subjects in three groups (lean, overweight, obese) for men and women (P = 0·02 and P = 0·05, respectively). Correlation analysis between levels of expression of visfatin and TNF‐α showed a significant positive linear association (r² = 0·27, P < 0·0001). Conclusion These findings reveal a probable new role of visfatin in inflammation reflected in PBMCs, in the context of obesity.     

Inflammatory markers and visceral fat are inversely associated with maximal oxygen consumption in women with polycystic ovary syndrome (PCOS)

Background We investigated whether several different inflammatory markers including C‐reactive protein (CRP) and fibrinogen and white blood cells (WBCs) count, are associated with maximal oxygen consumption (VO_2max) in women with polycystic ovary syndrome (PCOS). Methods In PCOS women (n = 124, 24·1 ± 4·5 year‐old) VO_2max was measured during symptom‐limited cardiopulmonary exercise test. Abdominal fat distribution was determined by ultrasound. Physical activity level was assessed by a standardized questionnaire. CRP was measured by immunoassays, fibrinogen by the Clauss method, and WBCs count with a Coulter counter. Results Pearson's analysis showed a significant correlation between VO_2max and logCRP (r = –0·437, P < 0·001), fibrinogen (r = –0·479, P < 0·001), and WBCs count (r = –0·438, P < 0·001). Multivariable logistic regression model showed that age (β = –0·127, P = 0·005), AUC_INS (β = –0·335, P < 0·001), HDL‐C (β = 0·390, P < 0·001), physical activity score (β = 0·238, P = 0·002), visceral fat (β =–0·184), P = 0·023), FAI (β = –0·291, P = 0·028); CRP (β = –0·216, P = 0·011), fibrinogen (β = –0·113, P = 0·008) and WBCs count (β = –0·177, P < 0·001) were significantly associated with VO_2max. Conclusions Acute‐phase reactants, such as CRP and fibrinogen, and WBCs count were independently and inversely associated with a direct measure of cardiorespiratory fitness (VO_2max) in women with PCOS, even after adjustment for physical activity level and other potential confounding factors. These findings add to the growing body of evidence linking inflammation to cardiorespiratory fitness in PCOS women.     

Lipid-lowering therapy does not affect the postprandial drop in high density lipoprotein-cholesterol (HDL-c) plasma levels in obese men with metabolic syndrome: a randomized double blind crossover trial

Introduction The postprandial lipid metabolism in metabolic syndrome patients is disturbed and may add to the increased cardiovascular risk in these patients. It is not known whether postprandial high density lipoprotein‐cholesterol (HDL‐c) metabolism is also affected and whether this can be influenced by statin and/or ezetimibe treatment. Methods Prospective, randomized, double blind, crossover trial comparing simvastatin 80 mg with simvastatin/ezetimibe 10 mg/10 mg treatment for 6 weeks on postprandial HDL‐c metabolism in 15, nonsmoking, male, obese metabolic syndrome patients (Adult Treatment Panel III, ATPIII). Only study medication was allowed. HDL‐c concentrations, cholesteryl ester transfer (CET), CET protein (CETP) mass and adiponectin were measured before and after oral fat loading. ClinicalTrials.gov NCT00189085. Results Plasma HDL‐c levels remained stable during continuous fasting following an overnight fast. Pre‐fat load HDL‐c concentrations without treatment, after simvastatin and simvastatin/ezetimibe treatment were 1·15 ± 0·04, 1·16 ± 0·05 and 1·11 ± 0·04 mmol/l. Fat load induced a 11% drop in HDL‐c plasma levels; 1·02 ± 0·05 mmol/l (P < 0·001) which was not affected by either therapy. Triglyceride levels during fat load were similar after both treatments. Total CET increased from 9·73 ± 0·70 to 12·20 ± 0·67 nmol/ml/h (P = 0·004). Four hours after fat loading CETP mass was increased while adiponectin levels were decreased, irrespective of treatment. Discussion HDL‐c levels decrease as CET increases after fat loading in obese metabolic syndrome patients. This is not influenced by either simvastatin or simvastatin/ezetimibe treatment. After fat loading, CETP mass and CET increased, and adiponectin decreased pointing towards a potential role for intra‐abdominal fat. Decreased postprandial HDL‐c levels may contribute to the increased cardiovascular risk in metabolic syndrome patients on top of already low HDL‐c levels.     

Thyroidal effect of metformin treatment in patients with polycystic ovary syndrome

Objective Metformin is widely used for the treatment of type 2 diabetes. Growing evidence supports the beneficial effects of metformin also in patients with polycystic ovary syndrome (PCOS). It was recently reported that metformin has a TSH‐lowering effect in hypothyroid patients with diabetes being treated with metformin. Design Aim of this study was to evaluate the effect of metformin treatment on the thyroid hormone profile in patients with PCOS. Patients and measurements Thirty‐three patients with PCOS were specifically selected for being either treated with levothyroxine for a previous diagnosis of hypothyroidism (n = 7), untreated subclinically hypothyroid (n = 2) or euthyroid without levothyroxine treatment (n = 24) before the starting of metformin. The serum levels of TSH and FT₄ were measured before and after a 4‐month period of metformin therapy. Results Thyroid function parameters did not change after starting metformin therapy in euthyroid patients with PCOS. In the 9 hypothyroid patients with PCOS, the basal median serum levels of TSH (3·2 mIU/l, range = 0·4–7·1 mIU/l) significantly (P < 0·05) decreased after a 4‐month course of metformin treatment (1·7 mIU/l, range = 0·5–5·2 mIU/l). No significant change in the serum levels of FT4 was observed in these patients. The TSH‐lowering effect of metformin was not related to the administered dose of the drug, which was similar in euthyroid as compared with hypothyroid patients with PCOS (1406 ± 589 vs 1322 ± 402 mg/day, respectively; NS). Conclusions These results indicate that metformin treatment has a TSH‐lowering effect in hypothyroid patients with PCOS, both treated with l ‐thyroxine and untreated.     

High plasma C-reactive protein (CRP) is related to low paraoxonase-I (PON-I) activity independently of high leptin and low adiponectin in type 2 diabetes mellitus

Objectives In type 2 diabetes mellitus, circulating C‐reactive protein (CRP) is increased, whereas the high density lipoprotein (HDL)‐associated, anti‐oxidative and anti‐inflammatory enzyme, paraoxonase‐I, is decreased. Both high CRP and low paraoxonase‐I activity may predict cardiovascular disease. It is unknown whether lower paraoxonase‐I activity contributes to higher CRP levels in diabetes. In type 2 diabetic and control subjects, we determined the relationship of CRP with paraoxonase‐I when taking account of plasma levels of pro‐ and anti‐inflammatory adipokines. Design and patients In 81 type 2 diabetic patients and 89 control subjects, plasma high‐sensitive CRP, serum paraoxonase‐I activity (arylesterase activity, assayed as the rate of hydrolysis of phenyl acetate into phenol), plasma leptin, adiponectin, resistin and lipids were determined. Results Body mass index (BMI), waist, insulin resistance, triglycerides, CRP, leptin and resistin levels were higher (P < 0·05 to P < 0·001), whereas HDL cholesterol, paraoxonase‐I activity and adiponectin levels were lower (P = 0·02 to P < 0·001) in diabetic compared to control subjects. Multiple linear regression analysis demonstrated that, after controlling for age and gender, CRP was inversely related to paraoxonase‐I activity (β = –0·15, P = 0·028) and adiponectin (β = –0·18, P = 0·009), and positively to leptin (β = 0·33, P < 0·001) and BMI (β = 0·22, P = 0·007), independently of the diabetic state (or of fasting glucose or HbA1c), insulin resistance and lipids (P > 0·20 for all). Conclusions low paraoxonase‐I activity is related to higher CRP, independently of adipokines, as well as of obesity and lipids. Low paraoxonase‐I activity in type 2 diabetes mellitus may contribute to increased cardiovascular risk via an effect on enhanced systemic low‐grade inflammation.     

Effects of T4 replacement therapy on glucose metabolism in subjects with subclinical (SH) and overt hypothyroidism (OH)

Objective To evaluate β‐cell function and insulin sensitivity in subjects with overt (OH) and subclinical hypothyroidism (SH) before and after T4 replacement therapy. Background Disturbances in glucose metabolism have been observed in hypothyroid states. However, the clinical significance and potential reversibility of these alterations by T4 replacement therapy remain to be elucidated especially in patients with SH. Design and patients Parameters of glucose metabolism have been investigated in subjects with OH (n = 12) and SH (n = 11). Insulin sensitivity has been assessed by the euglycaemic–hyperinsulinaemic clamp technique and β‐cell function by mathematical modelling of data derived from an oral glucose tolerance test. Results Fasting and dynamic glycaemia as assessed by the AUC_Glucose remained unaltered following substitution therapy (P > 0·05). Insulin sensitivity significantly improved only in subjects with OH (P < 0·05). Fasting insulin and proinsulin concentrations increased proportionally in both groups (P < 0·05) with the proinsulin : insulin ratio remaining unchanged (P > 0·05). Total insulin secretion was higher in OH before initiation of therapy (P < 0·05). In both groups, dynamic parameters including total insulin secretion, hepatic insulin extraction and the adaptation index were significantly attenuated (P < 0·05) after restoration of thyroid function, whereas the disposition index and the basal insulin secretion rate remained unaltered (P > 0·05). Conclusion In summary, SH and OH are characterized by attenuated basal plasma insulin levels and increased glucose‐induced insulin secretion. T4 replacement therapy partially ameliorates the insulin secretion profile and reduces the demand on pancreatic β‐cells after glucose challenge to an extent that exceeds any effect attributable to the improvement in insulin sensitivity.     

The antioxidant alpha-lipoic acid improves endothelial dysfunction induced by acute hyperglycaemia during OGTT in impaired glucose tolerance

Objective Impaired glucose tolerance (IGT) is considered a transitional phase in the development of type 2 diabetes, and is also independently associated with the occurrence of cardiovascular disease. Endothelial dysfunction (ED) represents a very early step in the development of atherosclerosis. The aim of the present study was to examine ED in the fasting state and after a glucose challenge as well as after administration of an antioxidant agent. Patients and methods The study subjects included 42 IGT patients and 26 healthy individuals (control group). The IGT patients were randomly divided into two groups, 21 in each group (the alpha‐lipoic acid group and the placebo group). In the alpha‐lipoic acid group, 300 mg of alpha‐lipoic acid was administrated before an oral glucose tolerance test (OGTT); in the placebo group, 250 ml of 0·9% sodium chloride was administrated before the OGTT. In addition, 250 ml of 0·9% sodium chloride was also administrated to the control subjects before the OGTT (control group), and then vascular function was examined in the fasting state and repeated 1 and 2 h after the glucose load. High‐resolution ultrasound was used to measure flow‐mediated endothelium‐dependent arterial dilation (FMD) and glyceryltrinitrate (GTN)‐induced endothelium‐independent arterial dilation. Results In the fasting state, and at 60 and 120 min, FMD in both the placebo and alpha‐lipoic acid groups was significantly lower than in the controls (P < 0·01). In the control group, FMD tended to decrease at 60 min after glucose loading and returned to the baseline levels at 120 min (P > 0·05). In the placebo group, FMD decreased significantly at 60 min after glucose loading (P < 0·01) and increased markedly from 60 to 120 min (P < 0·01). The alpha‐lipoic acid‐treated patients showed FMD values intermediate between the control subjects and the IGT patients treated with placebo, at both 60 and 120 min, and the differences were significant (P < 0·01). In multiple regression analysis, FMD was significantly correlated to fasting blood glucose (FBG), low density lipoprotein cholesterol (LDL‐C), lipoprotein (a) [Lp(a)], C‐reactive protein (CRP), thiobarbituric acid reactive substances (TBARS) and age in IGT patients at baseline (P < 0·01). Spearman's analysis showed a significant negative correlation between FMD and plasma glucose levels, and between FMD and TBARS during the OGTT in IGT patients (placebo group) (P < 0·01). There was also a significant correlation between FMD and plasma glucose levels, and between FMD and TBARS during the OGTT in IGT patients treated with alpha‐lipoic acid (P < 0·05), although the power of association decreased. Conclusion In subjects with IGT, FMD was impaired both in the fasting state and after a glucose challenge, probably through increased production of oxygen‐derived free radicals. The ED observed after a glucose challenge is related to the extent of hyperglycaemia and TBARS, and an antioxidant agent can improve the impairment of endothelial function induced by acute hyperglycaemia.     

GH and IGF-I deficiency are associated with reduced loss of fat mass after laparoscopic-adjustable silicone gastric banding

Context GH secretion is reduced in obese subjects and increases after body weight loss. It is still unclear if changes in the GH/IGF‐I axis after laparoscopic‐adjustable silicone gastric banding (LASGB) are associated with changes of body composition. Objective To analyse the relationships between changes in the GH/IGF‐I axis and those of body weight and composition before and after LASGB. Design Observational, prospective. Setting University ‘Federico II’ of Naples (Italy). Patients Seventy‐two severely obese females (BMI: 44·9 ± 4·68; mean age: 33·1 ± 11·34 years) were studied. Main outcome measures GH peak after GHRH plus arginine test, IGF‐I, IGFBP‐3 and ALS levels, fat mass (FM) and free fat mass (FFM) (by Bioelectrical Impedance Analysis) at baseline and 6 months after LASGB. The change in percentage of individual variables was calculated as well as that of excess of body weight loss (EBWL%). The FM%, FFM% and EBWL% were correlated with peak GH and IGF‐I levels changes. Results At baseline, GH deficiency (GHD) (GH peak = 4·1 µg/l) was found in 22 patients (31%), 16 of them also had IGF‐I deficiency (< –2SDS). IGF‐I levels were inversely correlated with waist circumference (r = –0·72, P < 0·001) and FM% (r = –0·75, P < 0·001). Post‐LASGB the patients were classified as follows: group (1) GH and IGF‐I sufficient (n = 44; 61·1%); group (2) GH and IGF‐I deficient (n = 14; 19·4%) and group (3) GH sufficient and IGF‐I deficient (n = 14; 19·4%). The percentage changes of EWBL (P < 0·05, P = 0·051, respectively) and FM (P < 0·001, P < 0·01, respectively) were lower in groups (2) and (3) than in group (1). At the stepwise linear regression analysis, postoperative IGF‐I levels were the strongest determinant of percent changes of FM (P < 0·0001), of FFM (P = 0·009) and of EBWL (P < 0·0001). Conclusions IGF‐I levels is the most sensitive to unfavourable changes in body composition 6 months after LASGB making investigation of the somatotropic axis useful in the evaluation of bariatric surgery outcomes.     

Acute hyperinsulinaemia and hyperlipidaemia modify circulating adiponectin and its oligomers

Objective Obesity and insulin resistance are associated with low adiponectin levels, although adiponectin is exclusively expressed in white adipose tissue. The mechanism beyond that paradox is not entirely clear, although insulin itself may reduce circulating adiponectin levels. However, obesity is also associated with hyperlipidaemia and the effects of free fatty acids (FFAs) and triglycerides (TG) on circulating adiponectin levels have not yet been investigated. Materials and methods We analysed the effect of an acute and euglycaemic elevation of insulin on adiponectin oligomers in 23 healthy individuals. In a subgroup including 11 healthy men, FFAs and TG were acutely elevated by infusion of heparin/lipids over 120 min. Again the effect on circulating adiponectin and its oligomers was investigated. Adiponectin was determined by ELISA, oligomers were detected by nondenaturating Western blot. Results Acute hyperinsulinaemia resulted in a significant reduction of total adiponectin to 7·74 ± 0·98 µg/ml (P = 0·004). High molecular weight (HMW) adiponectin did not change (0·80 ± 0·12 to 0·81 ± 0·14 µg/ml; P = 0·887), whereas MMW adiponectin decreased from 4·30 ± 0·51 to 3·78 ± 0·48 µg/ml (P = 0·005) and LMW adiponectin from 3·63 ± 0·42 to 3·15 ± 0·46 µg/ml (P = 0·048). Interestingly, heparin/lipid infusion also reduced circulating adiponectin levels (P = 0·001), which was primarily the result of reduced MMW adiponectin (P = 0·004), whereas LMW and HMW were not significantly affected. Conclusions The presented data suggest that both, hyperinsulinaemia and hyperlipidaemia, may contribute to low adiponectin levels in states of obesity.