Dunnigan lipodystrophy syndrome: French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins).

Dunnigan syndrome, or Familial Partial Lipodystrophy type 2 (FPLD2; ORPHA 2348), is a rare autosomal dominant disorder due to pathogenic variants of the LMNA gene. The objective of the French National Diagnosis and Care Protocol (PNDS; Protocole National de Diagnostic et de Soins), is to provide health professionals with a guide to optimal management and care of patients with FPLD2, based on a critical literature review and multidisciplinary expert consensus. The PNDS, written by members of the French National Reference Center for Rare Diseases of Insulin Secretion and Insulin Sensitivity (PRISIS), is available on the French Health Authority website (in French). Dunnigan syndrome is characterized by a partial atrophy of the subcutaneous adipose tissue and by an insulin resistance syndrome, associated with a risk of metabolic, cardiovascular and muscular complications. Its prevalence, assessed at 1/100.000 in Europe, is probably considerably underestimated. Thorough clinical examination is key to diagnosis. Biochemical testing frequently shows hyperinsulinemia, abnormal glucose tolerance and hypertriglyceridemia. Elevated hepatic transaminases (hepatic steatosis) and creatine phosphokinase, and hyperandrogenism in women, are common. Molecular analysis of the LMNA gene confirms diagnosis and allows for family investigations. Regular screening and multidisciplinary monitoring of the associated complications are necessary. Diabetes frequently develops from puberty onwards. Hypertriglyceridemia may lead to acute pancreatitis. Early atherosclerosis and cardiomyopathy should be monitored. In women, polycystic ovary syndrome is common. Overall, the management of patients with Dunnigan syndrome requires the collaboration of several health care providers. The attending physician, in conjunction with the national care network, will ensure that the patient receives optimal care through regular follow-up and screening. The various elements of this PNDS are described to provide such a support.

Bariatric surgery affects obesity-related protein requirements.

CONTEXT: Following bariatric surgery, protein deficiency intakes are reported in morbidly obese patients, whereas post-bariatric protein requirements are not specifically defined with validated method in this population. OBJECTIVE: To assess average protein requirement (APR) in obese subjects, before, 3 months and 12 months after bariatric surgery using the validated method of nitrogen balance. DESIGN AND SETTING: Prospective longitudinal study conducted in 21 morbidly obese patients (BMI 43.9 ± 1.4 kg/m2) before (M0), 3 months (M3) and 12 months (M12) after sleeve gastrectomy or Roux-en-Y gastric by-pass. An additional larger cross-sectional study was performed to validate APR before surgery in non-operated matched obese patients (n = 106). APR was evaluated at M0, M3, M12 by measuring 3 days dietary intakes together with losses of nitrogen in urine and stools. MAIN OUTCOME MEASURE: APR was defined as the mean value of protein intake required to achieve balance nitrogen equilibrium. RESULTS: Before surgery, APR in morbidly obese patients was 0.76 [95%CI, 0.66-0.92] g/kg Body Weight (BW)/d in the experimental group, and 0.74 [0.70-0.80] g/kg BW/d in the validation group. APR was 0.62 [0.51-0.75] g/kg/d at M3 and 0.87 [0.75-0.98] g/kg/d at M12, with no difference between surgical procedures. Spontaneous protein intakes were respectively 0.80 ± 0.05, 0.43 ± 0.03 and 0.71 ± 0.04 g/kg BW/d respectively at M0, M3 and M12. CONCLUSION: This study demonstrates a temporal change in protein requirement after bariatric surgery whatever the type of surgery. Spontaneous protein intakes following bariatric surgery does not cover protein requirements for most patients, suggesting that specific dietary protein recommandations have to be adapted in obese patients with bariatric surgery. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT01249326.

Bariatric surgery and the perioperative management of type 2 diabetes: Practical guidelines.

BACKGROUND: Metabolic surgery is now considered as a therapeutic option in type 2 diabetes (T2D). However, few data are available regarding perioperative management of T2D. OBJECTIVES: To assess current practice among bariatric teams regarding perioperative management of T2D in order to propose guidelines. METHODS: A two-round Delphi method using online surveys was employed among bariatric teams experts (surgeons, diabetologists, anesthetists, nutritionists): first round, 63 questions covering 6 topics (characteristics of experts/teams, characteristics of patients, operative technique, pre/postoperative management, diabetes remission); second round, 44 items needing clarification. They were discussed within national congress of corresponding learned societies. Consensus was defined as ≥66% agreement. RESULTS: A total of 170 experts participated. Experts favored gastric bypass to achieve remission (76.7%). Screening for retinopathy, cardiac ultrasound, and reaching an HbA1c<8% are required in the pre-operative period for 67%, 75.3% and 56.7% of experts, respectively. After surgery, insulin pump should not be stopped, basal insulin should be halved, and bolus insulin should be stopped except if severe hyperglycemia. DPP-IV inhibitors and metformin are preferred after surgery. Patients should be seen by a diabetologist within one month if on oral antidiabetic agents (71.8% of experts), 2 weeks if on injectable treatments (77.1% of experts), and immediately after surgery if on insulin pump (93.5% of experts). Long-term monitoring of HbA1c is necessary even if diabetes remission (100%). CONCLUSION: Rapid postoperative modifications of blood glucose require a close monitoring and a prompt adjustment of diabetes medications.

Ghrelin concentration as an indicator of eating-disorder risk in obese women.

AIM: Eating disorders (EDs), disordered eating (DE) and obesity are thought to have overlapping aetiological processes. DE in obesity can jeopardize weight-loss results, and acyl ghrelin (AG) is a hormone that stimulates food intake and reward processes. The main study objective was to determine whether higher-than-expected concentrations of AG in common obesity are associated with DE symptoms. METHODS: The study population included 84 women, aged 20-55 years, free of established EDs: 55 were severely obese (OB) and 29 were of normal weight (NW). OB participants were stratified into two groups according to their median concentration of fasting AG distribution. The OB women with a high fasting plasma ghrelin concentration (HGC) were compared with both OB women with a low fasting plasma ghrelin concentration (LGC) and NW women. Participants were assessed by the Eating Disorder Inventory (EDI-2), Three-Factor Eating Questionnaire (TFEQ) and Hospital Anxiety and Depression Scale (HADS). Fasting glucose, insulin, leptin and ghrelin plasma concentrations were also quantified. RESULTS: Between the two AG groups of OB women, there was no statistical difference in either anthropometric or metabolic parameters, HADS, TFEQ or fasting hunger scores. However, the HGC group scored significantly higher than the LGC group on the drive-for-thinness subscale of EDI-2 (9.30±0.99 vs. 6.46±0.83, respectively; P=0.033). CONCLUSION: Results support the hypothesis of a potential relationship between fasting plasma AG concentrations and ED risk, regardless of mood and anxiety. AG may be considered a potential biomarker of vulnerability for developing EDs.

Impact of Intragastric Balloon Before Laparoscopic Gastric Bypass on Patients with Super Obesity: a Randomized Multicenter Study.

BACKGROUND: Super obese patients are recommended to lose weight before bariatric surgery. The effect of intragastric balloon (IGB)-induced weight loss before laparoscopic gastric bypass (LGBP) has not been reported. The aim of this prospective randomized multicenter study was to compare the impact of preoperative 6-month IGB with standard medical care (SMC) in LGBP patients. METHODS: Patients with BMI >45 kg/m2 selected for LGBP were included and randomized to receive either SMC or IGB. After 6 months (M6), the IGB was removed and LGBP was performed in both groups. Postoperative follow-up period was 6 months (M12). The primary endpoint was the proportion of patients requiring ICU stay >24 h; secondary criteria were weight changes, operative time, hospitalization stay, and perioperative complications. RESULTS: Only 115 patients were included (BMI 54.3 ± 8.7 kg/m2), of which 55 underwent IGB insertion. The proportion of patients who stayed in ICU >24 h was similar in both groups (P = 0.87). At M6, weight loss was significantly greater in the IGB group than in the SMC group (P < 0.0001). Three severe complications occurred during IGB removal. Mean operative time for LGBP was similar in both groups (P = 0.49). Five patients had 1 or more surgical complications, all in the IGB group (P = 0.02). Both groups had similar hospitalization stay (P = 0.59) and weight loss at M12 (P = 0.31). CONCLUSION: IGB insertion before LGBP induced weight loss but did not improve the perioperative outcomes or affect postoperative weight loss.

Plasma acyl-ghrelin increases after meal initiation: a new insight.

BACKGROUND/OBJECTIVES: Plasma ghrelin secretion over time in humans is characterized by pre-prandial increases and by post-prandial decreases all day long. However, some authors who measured ghrelin concentrations around meals showed a rise in plasma ghrelin concentration after meal initiation followed by the typical post-prandial decrease. In order to confirm this observation that has never been discussed, we described ghrelin profiles around four eating episodes in the morning in adult men. SUBJECTS/METHODS: Twenty normal-weight and 17 obese men were instructed to eat four fixed meals (706 kJ) 10 min long at 0800 h, 0900 h, 1000 h and 1100 h. Using frequent blood sampling, we determined plasma acyl-ghrelin concentrations around those eating episodes. Glucose, insulin and GLP-1 concentrations were also measured. RESULTS: The meals consumption induced a significant increase in plasma acyl-ghrelin concentrations 10 min after meal initiation (P<0.0001): +20.9±5.8 and +10.7±3.3 pg/ml in normal-weight and obese subjects for the first meal; +10.4±3.0 and +5.5±3.9 pg/ml in normal-weight and obese subjects for the second meal; +12.4±3.6 and +4.2±2.1 pg/ml in normal-weight and obese subjects for the third meal; and +4.4±4.1 and +3.3±2.61 pg/ml in normal-weight and obese subjects for the fourth meal. CONCLUSIONS: This study is the first to describe and discuss the post-meal initiation ghrelin increase. This finding is consistent in normal-weight and obese individuals.

Are third-trimester adipokines associated with higher metabolic risk among women with gestational diabetes?

AIM: This study aimed to determine whether third-trimester adipokines during gestational diabetes (GDM) are associated with higher metabolic risk. METHODS: A total of 221 women with GDM (according to IADPSG criteria) were enrolled between 2011/11 and 2013/6 into a prospective observational study (IMAGE), and categorized as having elevated fasting blood glucose (FBG) or impaired fasting glucose (IFG, n = 36) if levels were ≥ 92 mg/dL during a 75-g oral glucose tolerance test (OGTT), impaired glucose tolerance (IGT, n = 116) if FBG was < 92 mg/dL but with elevated 1-h or 2-h OGTT values, or impaired fasting and stimulated blood glucose (IFSG, n = 69) if both FBG was ≥ 92 mg/dL and 1-h or 2-h OGTT values were elevated. RESULTS: Pre-gestational body mass index (BMI) was higher in women with IFG or IFSG compared with IGT (P < 0.001), as were leptin levels in women with IFG vs IGT [34.7 (10.5-119.7) vs 26.6 (3.56-79.4) ng/L; P = 0.008]. HOMA2-IR scores were higher in women with IFG or IFSG vs IGT (1.87 ± 1.2 or 1.72 ± 0.9 vs 1.18 ± 0.8, respectively; P < 0.001). Also, those with IFSG vs those with IGT had significantly lower HOMA2-B scores (111.4 ± 41.3 vs 127.1 ± 61.6, respectively; P < 0.05) and adiponectin levels [5.00 (1.11-11.3) vs 6.19 (2.11-17.7) µg/mL; P < 0.001], and higher levels of IL-6 [1.14 (0.33-20.0) vs 0.90 (0.31-19.0); P = 0.012] and TNF-α [0.99 (0.50-10.5) vs 0.84 (0.45-11.5) pg/mL; P = 0.003]. After adjusting for age, parity, and pre-gestational and gestational BMI, the difference in adiponectin levels remained significant. CONCLUSION: Diagnosing GDM by IADSPG criteria results in a wide range of heterogeneity. Our study has indicated that adipokine levels in addition to FBG may help to select women at high metabolic risk for appropriate monitoring and post-delivery interventions (ClinicalTrials.gov number NCP02133729).

Increased TSH in obesity: Evidence for a BMI-independent association with leptin.

AIM: This study aimed to determine whether the association between thyroid-stimulating hormone (TSH) and body mass index (BMI) is related to leptin concentration in obese individuals. METHODS: Plasma TSH and leptin assays were performed in 800 consecutive patients, hospitalized for a nutritional checkup, with a BMI ≥ 30 kg/m(2). Various anthropometric, hormonal and metabolic parameters, including age, weight, BMI, insulin, leptin and TSH, were measured or calculated. Univariate and multivariate regression analyses were performed to identify any significant relationships between these parameters. Also, characteristics of the patients in the lowest and highest quartiles of TSH distribution were compared. RESULTS: TSH was positively correlated with both BMI and leptin. When multiple regression analysis was performed, TSH and leptin maintained a significant association independent of BMI. Patients in the fourth quartile of TSH distribution displayed higher BMI and higher leptin levels in comparison to the first quartile. CONCLUSION: Our study has confirmed an increase in TSH in conjunction with BMI in obese subjects. This increase was correlated with leptin independently of BMI. It is hypothesized that the increase in TSH observed in obese subjects was the consequence of both fat mass accumulation and a positive energy-balance.

Regulation of energy metabolism and mitochondrial function in skeletal muscle during lipid overfeeding in healthy men.

CONTEXT/OBJECTIVE: The aim of this study was to evaluate the regulation of the fuel partitioning and energy metabolism in skeletal muscle during lipid overfeeding in healthy men. Design/Participants/Intervention: Thirty-nine healthy volunteers were overfed for 56 days with a high-fat diet (3180 kJ/d). Energy metabolism (indirect calorimetry) was characterized in the fasting state and during a test meal before and at the end of the diet. Skeletal muscle biopsies were taken at day 0 and day 56. MAIN OUTCOME MEASURES: Change in gene expression, mitochondrial respiration, nicotinamide adenine dinucleotide (NAD(+)) content, and acetylation of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) in skeletal muscle was measured. RESULTS: Overfeeding increased body weight (+2.6 kg) and fat mass concomitantly with a shift in the use of substrates as energy fuel toward preferential oxidation of carbohydrates instead of lipids. Changes in lipid metabolic gene expression supported this observation, with a reduction in pyruvate dehydrogenase kinase 4 expression that could be the consequences of decreased NAD(+) concentration and reduced deacetylase activity of the sirtuins, as supported by hyperacetylation of PGC-1α after overfeeding. Interestingly, this reduction of the sirtuin PGC-1α pathway was associated with increased mitochondrial gene expression and higher respiration rate under these conditions. CONCLUSION: Adaptation to lipid overfeeding and regulation of fuel partitioning in human muscle appear to rely on a dissociation between the regulatory functions of the sirtuin-PGC-1α pathway on fatty acid oxidation and on mitochondrial regulation. This may facilitate lipid storage during a period of positive energy balance while maintaining mitochondrial functions and oxidative capacities.

Greater weight loss with the omega loop bypass compared to the Roux-en-Y gastric bypass: a comparative study.

BACKGROUND: Despite similar initial results on weight loss and metabolic control, with a better feasibility than the Roux-en-Y gastric bypass (RYGBP), the omega loop bypass (OLB) remains controversial. The aim of this study was to compare the short-term outcomes of the laparoscopic OLB versus the RYGBP in terms of weight loss, metabolic control, and safety. METHODS: Two groups of consecutive patients who underwent laparoscopic gastric bypass surgery were selected: 20 OLB patients and 61 RYGBP patients. Patients were matched for age, gender, and initial body mass index (BMI). Data concerning weight loss, metabolic outcomes, and complications were collected prospectively. RESULTS: Mean duration of the surgical procedure was shorter in the OLB group (105 vs. 152 min in the RYGBP group; p < 0.001). Mean excess BMI loss percent (EBL%) at 6 months and at 1 year was greater in the OLB group (76.3 vs. 60.0%, p = 0.001, and 89.0 vs. 71.0%, p = 0.002, respectively). After adjustment for age, sex, initial BMI, and history of previous bariatric surgery, the OLB procedure was still associated with a significantly greater 1-year EBL%. Diabetes improvement at 6 months was similar between both groups. The early and late complication rates were not statistically different. There were three anastomotic ulcers in the OLB group, in smokers, over 60 years old, who were not taking proton pump inhibitor medication. CONCLUSIONS: In this short-term study, we observed a greater weight loss with OLB and similar efficiency on metabolic control compared to RYGBP. Long-term evaluation is necessary to confirm these outcomes.

Fasting insulin at baseline influences the number of cardiometabolic risk factors and R-R interval at 3years in a healthy population: the RISC Study.

AIM: This was a cross-sectional and longitudinal study of factors contributing to the number of cardiometabolic risk factors, common carotid artery intima-media thickness (CCA-IMT) and R-R interval in clinically healthy subjects without diabetes. METHODS: Anthropometric and cardiometabolic parameters were measured in the Relationship between Insulin Sensitivity and Cardiovascular Disease (RISC) Study cohort at baseline (n=1211) and 3years later (n=974). At baseline, insulin sensitivity was assessed by the euglycaemic clamp technique. The CCA-IMT was echographically measured and the R-R interval was electrocardiographically evaluated at baseline and at the 3-year follow-up. RESULTS: Higher baseline BMI, fasting insulin and tobacco use as well as greater changes in BMI and fasting insulin but lower adiponectin levels, were associated with a greater number of cardiometabolic risk factors at the 3-year follow-up independently of insulin sensitivity (all P<0.02). The CCA-IMT increased with the number of cardiometabolic risk factors (P=0.008), but was not related to fasting insulin, whereas higher fasting insulinaemia and its 3-year changes were significantly associated with a smaller R-R interval (P=0.005 and P=0.002, respectively). These relationships were independent of baseline age, gender, BMI, adiponectin, insulin sensitivity, tobacco use and physical activity. CONCLUSION: In clinically healthy subjects, fasting insulinaemia, adiponectin and lifestyle parameters are related to the presence of one or two cardiometabolic risk factors before criteria for the metabolic syndrome are met. These results underline the importance of fasting insulinaemia as an independent cardiometabolic risk factor at an early stage of disease development in a healthy general population.

Predictive factors of type 2 diabetes remission 1 year after bariatric surgery: impact of surgical techniques.

Type 2 diabetes (T2D) remission after bariatric procedures has been highlighted in many retrospective and some recent prospective studies. However, in the most recent prospective study, more than 50 % of patients did not reach T2D remission at 1 year. Our aim was to identify baseline positive predictors for T2D remission at 1 year after bariatric surgery and to build a preoperative predictive score. We analysed the data concerning 161 obese operated on between June 2007 and December 2010. Among them, 46 were diabetic and were included in the study-11 laparoscopic adjustable gastric banding (LAGB), 26 Roux-en-Y gastric bypass (RYGB) and 9 sleeve gastrectomy (SG). We compared anthropometric and metabolic features during 1 year of follow-up. A receiver operating characteristic analysis was performed to predict T2D remission. RYGB and SG were similarly efficient for body weight loss and more efficient than LAGB; 62.8 % of patients presented with T2DM remission at 1 year, with no significant difference according to the surgical procedure. A 1-year body mass index (BMI) <35 kg m(-2) was predictive of T2DM remission whatever the procedure. The preoperative predictive factors of diabetes remission were baseline BMI ≤50 kg m(-2), duration of type 2 diabetes ≤4 years, glycated haemoglobin ≤7.1 %, fasting glucose <1.14 g/l and absence of insulin therapy. A short duration of diabetes and good preoperative glycaemic control increase the rate of T2DM remission 1 year after surgery. Preoperative metabolic data could be of greater importance than the choice of bariatric procedure.

Heterogeneity of pregnancy outcomes and risk of LGA neonates in Caucasian females according to IADPSG criteria for gestational diabetes mellitus.

OBJECTIVE: The International Association of Diabetes and Pregnancy Study Group (IADPSG) guidelines for gestational diabetes mellitus (GDM) diagnosis determines that fasting, 1-h and 2-h glucose values may contribute independently to adverse outcomes. However, given the different physiological bases of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), differences in pregnancy outcomes are to be expected. This study aimed to determine whether classification of GDM women according to glucose homoeostasis results in heterogeneity in maternal and/or fetal outcomes. MATERIAL AND METHODS: Of the 75 pregnant women included after a 75-g 2-h OGTT performed between weeks 24-32 of gestation as per WHO criteria, 55 were classified as GDM (16 with IFG and 39 with IGT) according to IADSPG criteria. Their anthropometric and metabolic characteristics were compared with those of non-GDM women with IFG or IGT. Maternal and neonatal outcomes were prospectively recorded for each group. RESULTS: GDM women with IFG, including isolated IFG and combined IFG+IGT, were significantly heavier, had higher leptin values and were more frequently multiparous than GDM women with isolated IGT. HOMA-IR was significantly higher when fasting glucose was impaired. There were no significant differences in maternal outcomes according to metabolic status. In addition, large for gestational age (LGA) neonates were significantly seen more often in the IFG group. Fasting glucose was significantly associated with LGA independently of BMI and 2-h OGTT glucose. The>5.1mmol/L cut-off value for fasting glucose was highly predictive of delivery of LGA infants. CONCLUSION: IFG in GDM women was associated with increases in BMI, fat mass and hepatic insulin resistance. Delivery of LGA neonates was more frequent when fasting glycaemia was increased during the third trimester of pregnancy, and was independent of BMI and 2-h OGTT glucose values.

Moderate alcohol consumption is associated with improved insulin sensitivity, reduced basal insulin secretion rate and lower fasting glucagon concentration in healthy women.

AIMS/HYPOTHESIS: Moderate alcohol consumption is associated with a reduced risk of type 2 diabetes with a stronger effect in women. As the underlying mechanisms remain poorly characterised, we investigated its relationship with insulin resistance, insulin secretion, clearance of insulin and glucagon concentration. METHODS: One-thousand two-hundred and seventy-six non-diabetic individuals from the RISC (relationship between insulin sensitivity and cardiovascular disease) study without high alcohol consumption were studied; all had a euglycaemic-hyperinsulinaemic clamp and an OGTT with assessment of insulin sensitivity, secretion and clearance. RESULTS: Alcohol consumption was positively associated with insulin sensitivity in women (ß = 0.15, p ( trend ) = 0.005) and in men (ß = 0.07, p ( trend ) = 0.07) after controlling for age, centre, waist, smoking and physical activity. In women, this association persisted after adjustment for adiponectin but was attenuated after controlling for HDL-cholesterol, suggesting that part of the protection is related to a higher HDL-cholesterol concentration. Higher alcohol consumption was associated with lower basal insulin secretion in women only (ß = -0.10, p ( trend ) = 0.004) and this association persisted after adjustment for insulin sensitivity. In men, increasing alcohol consumption was associated with enhanced insulin clearance and increased fasting NEFA concentrations, independently of insulin sensitivity. Fasting glucagon decreased with increasing alcohol in women only (abstainers 9.2 ± 4.4; <28 g/week 8.6 ± 4.0; 28-64 g/week 8.1 ± 3.7; >64 g/week 7.5 ± 3.1 pmol/l; p ( trend ) = 0.01). CONCLUSIONS/INTERPRETATION: Light-to-moderate alcohol consumption was associated in healthy women with enhanced insulin sensitivity, reduced basal insulin secretion rate and lower fasting plasma glucagon concentration, providing consistent mechanisms for the reduced risk of diabetes.

How can we measure insulin sensitivity/resistance?

Insulin resistance represents a major public health problem, as it plays a major role in the pathophysiology of type 2 diabetes mellitus; it is also associated with increased cardiovascular risk and atherogenic dyslipidaemia, and is a central component of the cluster of metabolic abnormalities that comprise the metabolic syndrome. Thus, the development of tools to quantify insulin sensitivity/resistance has been the main objective of a number of studies. Insulin resistance can be estimated with the use of several biological measurements that evaluate different aspects of this complex situation. To that end, it requires various resources, ranging from just a single fasting blood sample for simple indices, such as the HOMA or QUICKI, to a research setting in which to perform the gold-standard hyperinsulinaemic-euglycaemic clamp test. The choice of method for evaluating insulin resistance depends on the nature of the information required (classification of individual subjects, group comparisons, precise measurement of either global, muscle or liver insulin sensitivity/resistance) and on the available resources. The aim of this review is to analyze the most frequently used assay methods in an attempt to evaluate when and why these methods may be useful.

Systemic ghrelin and reward: effect of cholinergic blockade.

AIMS: Ghrelin is one of the most potent orexigens known to date. Recent data suggested that ghrelin is involved in reward-mediated processes such as the rewarding value of food. Whereas the neuronal pathways by which ghrelin regulates energy balance are well described, those involved in ghrelin-induced reward are still confusing. Therefore, we attempted to delineate the involvement of physiological and pharmacological rises in plasma ghrelin in the modulation of food reward seeking behaviours, using the classical conditioned place preference (CPP) procedure in C57BL6J mice, as well as in mice lacking the ghrelin receptor (GHSR1a -/-). We also determined whether these effects on reward-related behaviours could be partly mediated by cholinergic pathways by pre-treating mice with mecamylamine. RESULTS: Upon moderate caloric restriction, systemic ghrelin levels increased from 108 ± 21 to 148 ± 39 pg/ml in C57BL6J mice and from 111 ± 24 to 179 ± 41 pg/ml in GHSR1a-null mice. Short exposure to rewarding food elicited a strong CPP and stimulation of locomotor activity in GHSR1a wild-type and C57BL6J mice. Conversely, the GHSR1a -/- mice did not exhibit such a food CPP, despite a negative energy balance. Pharmacological rise in systemic ghrelin further increased the time spent in the food-paired side with a higher CPP score (+71%) and this effect was blunted after cholinergic blockade by mecamylamine. CONCLUSIONS: The ghrelin receptor is obligatory to acquire a food-CPP. The level of plasma ghrelin during conditioning determines the strength of food-induced reward seeking behaviours. The cholinergic pathway partly mediates the further enhancement of food reward induced by pharmacological rises in plasma ghrelin, but not that induced by physiological increases in ghrelin.

Microarray analysis of genes with impaired insulin regulation in the skeletal muscle of type 2 diabetic patients indicates the involvement of basic helix-loop-helix domain-containing, class B, 2 protein (BHLHB2).

AIMS/HYPOTHESIS: One of the major processes by which insulin exerts its multiple biological actions is through gene expression regulation. Thus, the identification of transcription factors affected by insulin in target tissues represents an important challenge. The aim of the present study was to gain a greater insight into this issue through the identification of transcription factor genes with insulin-regulated expression in human skeletal muscle. METHODS: Using microarray analysis, we defined the sets of genes modulated during a 3 h hyperinsulinaemic-euglycaemic clamp (2 mU min(-1) kg(-1)) in the skeletal muscle of insulin-sensitive control volunteers and in moderately obese insulin-resistant type 2 diabetic patients. RESULTS: Of the 1,529 and 1,499 genes regulated during the clamp in control and diabetic volunteers, respectively, we identified 30 transcription factors with impaired insulin-regulation in type 2 diabetic patients. Analysis of the promoters of the genes encoding these factors revealed a possible contribution of the transcriptional repressor basic helix-loop-helix domain-containing, class B, 2 protein (BHLHB2), insulin regulation of which is strongly altered in the muscle of diabetic patients. Gene ontology analysis of BHLHB2 target genes, identified after BHLHB2 overexpression in human primary myotubes, demonstrated that about 10% of the genes regulated in vivo during hyperinsulinaemia are potentially under the control of this repressor. The data also suggested that BHLHB2 is situated at the crossroads of a complex transcriptional network that is able to modulate major metabolic and biological pathways in skeletal muscle, including the regulation of a cluster of genes involved in muscle development and contraction. CONCLUSIONS/INTERPRETATION: We have identified BHLHB2 as a potential novel mediator of insulin transcriptional action in human skeletal muscle.