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Background: Obesity is associated with varying degrees of metabolic dysfunction. In this study, we aimed to discover markers of the severity of metabolic impairment in men with obesity via a multiomics approach., Methods: Thirty-two morbidly men with obesity who were candidates for Roux-en-Y gastric bypass (RYGB) surgery were prospectively followed. Nine healthy adults served as controls. Deep phenotyping, including targeted metabolomics, transcriptomics, and brain magnetic resonance imaging (MRI), was performed., Results: Testosterone emerged as a key contributor to phenotypic variability via principal component analysis and was therefore used to further categorize obese patients as having or not having hypogonadotropic hypogonadism (HH). Despite having comparable body mass indices, obese individuals with HH presented with worse metabolic defects than obese individuals without HH, including higher insulin resistance, as well as MRI signs of hypothalamic inflammation and a specific blood transcriptomics signature. The upregulated genes were involved mainly in inflammation, mitochondrial function, and protein translation. Integration of gene expression and clinical data revealed high FGF21 and low cortisol levels as the top markers correlated with the transcriptomic signature of metabolic risk. Following RYGB-induced substantial weight loss, testosterone levels markedly increased in both obese individuals with and without HH, challenging the current definition of hypogonadism. A longitudinal study in a subset of men with obesity following bariatric surgery revealed a unique FGF21 trajectory with a sharp peak at one month post-RYGB that correlated with metabolic and reproductive improvements., Conclusions: Combining clinical, biochemical, and molecular markers allows adequate stratification of metabolic risk in men with obesity and provides novel tools for personalized care., Competing Interests: Declarations. Ethics approval and consent to participate: The research protocol was approved by the Institutional Ethics Committee for Research of the Canton of Vaud, Switzerland (CER-VD), and written informed consent was obtained from all participants. Consent for publication: Not applicable. Competing interests: The authors declare that they have no competing interests., (© 2025. The Author(s).)

Background: Postbariatric hypoglycemia (PBH) is a challenging condition affecting quality of life of patients after bariatric surgery. However, its incidence and predictive factors remain debated., Objectives: To determine the incidence of PBH, identify predictors of PBH and assess its association with weight trajectory after bariatric surgery., Setting: University Hospital., Methods: Prospective observational cohort study including 222 nondiabetic patients who underwent Roux-en-Y gastric bypass between 2014 and 2021, had an oral glucose tolerance test (OGTT) and/or A1C (glycated hemoglobin) measurement prior to surgery and were followed for at least 12 months. Diagnosis of PBH was made when symptoms of hypoglycemia were accompanied by a postprandial plasma glucose level < 3.9 mmol/l or a glycemia < 3.9 mmol/l during continuous glucose monitoring, with resolution of symptomatology after carbohydrate consumption. Univariable and multivariable logistic regression analyses were performed to identify factors associated with PBH., Results: Out of 222 patients, 71 (32%) were diagnosed with PBH. The highest incidence rate was observed at 2 years postbariatric surgery with a cumulative incidence of 26.5%. Predictive factors for higher risk of PBH were younger age at surgery (OR = .97; 95% CI: .94-.99; P = .049) and early dumping syndrome (OR = 3.05; 95% CI: 1.62-6.04; P = .0008). In multivariable logistic regression, higher glycemia at 2 hours during preoperative OGTT was associated with lower risk of PBH (OR = .8; 95% CI: .63-.98; P = .04). PBH was not associated with weight trajectory after surgery in our cohort., Conclusions: Younger age at time of surgery and lower blood glucose at 120 minute during preoperative OGTT are risk factors for PBH. Early dumping syndrome is significantly associated with PBH and could be used as a red flag to help identify patients at risk of PBH., (Copyright © 2024 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Adipose tissue plasticity is orchestrated by molecularly and functionally diverse cells within the stromal vascular fraction (SVF). Although several mouse and human adipose SVF cellular subpopulations have by now been identified, we still lack an understanding of the cellular and functional variability of adipose stem and progenitor cell (ASPC) populations across human fat depots. To address this, we performed single-cell and bulk RNA sequencing (RNA-seq) analyses of >30 SVF/Lin- samples across four human adipose depots, revealing two ubiquitous human ASPC (hASPC) subpopulations with distinct proliferative and adipogenic properties but also depot- and BMI-dependent proportions. Furthermore, we identified an omental-specific, high IGFBP2-expressing stromal population that transitions between mesothelial and mesenchymal cell states and inhibits hASPC adipogenesis through IGFBP2 secretion. Our analyses highlight the molecular and cellular uniqueness of different adipose niches, while our discovery of an anti-adipogenic IGFBP2+ omental-specific population provides a new rationale for the biomedically relevant, limited adipogenic capacity of omental hASPCs., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Conflicting results have been reported regarding the predictive value of preoperative psychological assessment and weight outcome after bariatric surgery. This might be attributed to different factors affecting early weight loss and long-term weight loss. Herein, we investigated whether preoperative psychiatric profile was associated with preoperative BMI and with both early (1 year) and long-term (5 years) weight loss after Roux-en-Y gastric bypass (RYGB)., Methods: Prospective observational cohort study of patients undergoing RYGB between 2013 and 2019. Symptoms related to anxiety, depression, eating disorder, and alcohol use disorders were assessed by employing validated, specific psychometric tests (STAI-S/T, BDI-II, BITE, AUDIT-C) prior to surgery. Pre-operative BMI, early weight loss (1 year), and long-term weight evolution (up to 5 years) were registered., Results: Two hundred thirty six patients (81% women) were included in the present study. Linear longitudinal mixed model showed a significant effect of preoperative high anxiety (STAI-S) on long-term weight outcome, after controlling for gender, age and type 2 diabetes. Patient with high preoperative anxiety score regained weight faster than those experiencing low anxiety (each year percent excess BMI loss (%EBMIL) - 4.02%, ± 1.72, p = 0.021). No other pre-operative psychiatric symptoms have been shown to have an impact on long-term weight loss. In addition, no significant association was found between any of the pre-operative psychiatric variables and pre-operative BMI, or early weight loss (%EBMIL) at 1-year post-RYGB., Conclusion: Herein we identified high anxiety score (STAI-S) as a predictor for long-term weight regain. Thus, long-term psychiatric surveillance of these patients and the development of tailored management tools could serve as a means to prevent weight regain., (© 2023. The Author(s).)

Purpose: Roux-en-Y gastric bypass (RYGB) involves alterations of the gastrointestinal tract resulting in altered absorption. Patients with obesity have a higher prevalence of depression, and antidepressants are often prescribed. Alterations caused by RYGB could modify drug bioavailability and cause potential subtherapeutic plasma concentrations, increasing the risk of depressive relapse. The aim of this study was to describe the evolution of trough drug dose-normalized antidepressant plasma concentrations before and after RYGB., Materials and Methods: This naturalistic prospective case series considers patients with trough plasma concentrations in a 1-year timeframe before and after RYGB. Only antidepressants prescribed to at least three patients were included in the present study., Results: Thirteen patients (n = 12 females, median age 44 years, median BMI before intervention = 41.3 kg/m 2 ) were included. Two patients were treated concurrently with fluoxetine and trazodone; the remaining patients were all treated with antidepressant monotherapy. Therapeutic drug monitoring (TDM) values for duloxetine (n = 3), escitalopram (n = 4), fluoxetine (n = 4), and trazodone (n = 4) before (median 4.7 weeks) and after (median 21.3 weeks) RYGB intervention were analyzed. Compared to preintervention, median [interquartile range] decreases in dose-normalized trough plasma concentrations for duloxetine (33% [- 47; - 23]), escitalopram (43% [- 51; - 31]), fluoxetine (9% [- 20; 0.2]), and trazodone (16% [- 29; 0.3]) were observed., Conclusion: This study shows a decrease in plasma antidepressant concentrations following RYGB. TDM before and after RYGB, in addition to close monitoring of psychiatric symptomatology, may help optimize antidepressant treatment after bariatric surgery. These results also highlight the need for prospective studies assessing the clinical evidence available through TDM in these patients., (© 2023. The Author(s).)

Objective: This study investigated the effectiveness of liraglutide 3.0 mg daily in combination with a standardized multidisciplinary intervention on body weight and body composition changes in a real-life setting., Methods: A prospective, observational cohort study design was used. Adult patients with BMI > 35 kg/m 2 , or BMI > 28 kg/m 2 with greater than or equal to one metabolic comorbidity, were included (n = 54, 65% women). Liraglutide treatment was covered by Swiss health insurance. Clinical and biological data were collected at baseline, 4 months, and 10 months. Body composition was assessed by dual-energy x-ray absorptiometry at baseline and 10 months., Results: At 10 months, mean (SD) percentage weight loss (WL%) was -12.4% (5.5%) or -14.1 (6.6) kg. WL% was ≥5% in 87% of patients at 4 months and in 96% at 10 months. WL% was higher in women (-9.5% [3.1%] vs. men -7.2% [2.5%], p = 0.02) at 4 months and persisted at 10 months (-13.7% [5.2%] vs. -9.6% [5.1%], p = 0.006). WL% was associated with baseline percentage fat mass but not with age or BMI. Body composition showed a decrease in fat mass, visceral adipose tissue, and absolute lean mass., Conclusions: In a real-world setting, liraglutide 3.0 mg led to beneficial changes in WL and body composition, with a greater impact in women., (© 2022 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.)

The identification of molecular biomarkers that can be used to quantitatively link dietary intake to phenotypic traits in humans is a key theme in modern nutritional research. Although dairy products (with and without fermentation) represent a major food group, the identification of markers of their intake lags behind that of other food groups. Here, we report the results from an analysis of the metabolites in postprandial serum and urine samples from a randomized crossover study with 14 healthy men who ingested acidified milk, yogurt, and a non-dairy meal. Our study confirms the potential of lactose and its metabolites as markers of lactose-containing dairy foods and the dependence of their combined profiles on the fermentation status of the consumed products. Furthermore, indole-3-lactic acid and 3-phenyllactic acid are two products of fermentation whose postprandial behaviour strongly discriminates yogurt from milk intake. Our study also provides evidence of the ability of milk fermentation to increase the acute delivery of free amino acids to humans. Notably, 3,5-dimethyloctan-2-one also proves to be a specific marker for milk and yogurt consumption, as well as for cheese consumption (previously published data). These molecules deserve future characterisation in human interventional and observational studies.

Introduction and Aims: Dietary polyphenols have long been associated with health benefits, including the prevention of obesity and related chronic diseases. Overfeeding was shown to rapidly induce weight gain and fat mass, associated with mild insulin resistance in humans, and thus represents a suitable model of the metabolic complications resulting from obesity. We studied the effects of a polyphenol-rich grape extract supplementation on the plasma metabolome during an overfeeding intervention in adults, in two randomized parallel controlled clinical trials., Methods: Blood plasma samples from 40 normal weight to overweight male adults, submitted to a 31-day overfeeding (additional 50% of energy requirement by a high calorie-high fructose diet), given either 2 g/day grape polyphenol extract or a placebo at 0, 15, 21, and 31 days were analyzed (Lyon study). Samples from a similarly designed trial on females (20 subjects) were collected in parallel (Lausanne study). Nuclear magnetic resonance (NMR)-based metabolomics was conducted to characterize metabolome changes induced by overfeeding and associated effects from polyphenol supplementation. The clinical trials are registered under the numbers NCT02145780 and NCT02225457 at ClinicalTrials.gov., Results: Changes in plasma levels of many metabolic markers, including branched chain amino acids (BCAA), ketone bodies and glucose in both placebo as well as upon polyphenol intervention were identified in the Lyon study. Polyphenol supplementation counterbalanced levels of BCAA found to be induced by overfeeding. These results were further corroborated in the Lausanne female study., Conclusion: Administration of grape polyphenol-rich extract over 1 month period was associated with a protective metabolic effect against overfeeding in adults., Competing Interests: Authors SB, JC, JH, and SoM were employees of Nestlé Research when this study was conducted. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bartova, Madrid-Gambin, Fernández, Carayol, Meugnier, Segrestin, Delage, Vionnet, Boizot, Laville, Vidal, Marco, Hager and Moco.)

At the present time, no viable treatment exists for cognitive and olfactory deficits in Down syndrome (DS). We show in a DS model (Ts65Dn mice) that these progressive nonreproductive neurological symptoms closely parallel a postpubertal decrease in hypothalamic as well as extrahypothalamic expression of a master molecule that controls reproduction-gonadotropin-releasing hormone (GnRH)-and appear related to an imbalance in a microRNA-gene network known to regulate GnRH neuron maturation together with altered hippocampal synaptic transmission. Epigenetic, cellular, chemogenetic, and pharmacological interventions that restore physiological GnRH levels abolish olfactory and cognitive defects in Ts65Dn mice, whereas pulsatile GnRH therapy improves cognition and brain connectivity in adult DS patients. GnRH thus plays a crucial role in olfaction and cognition, and pulsatile GnRH therapy holds promise to improve cognitive deficits in DS.

Two randomized placebo-controlled double-blind paralleled trials (42 men in Lyon, 19 women in Lausanne) were designed to test 2 g/day of a grape polyphenol extract during 31 days of high calorie-high fructose overfeeding. Hyperinsulinemic-euglycemic clamps and test meals with [1,1,1- 13 C 3 ]-triolein were performed before and at the end of the intervention. Changes in body composition were assessed by dual-energy X-ray absorptiometry (DEXA). Fat volumes of the abdominal region and liver fat content were determined in men only, using 3D-magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) at 3T. Adipocyte's size was measured in subcutaneous fat biopsies. Bodyweight and fat mass increased during overfeeding, in men and in women. While whole body insulin sensitivity did not change, homeostasis model assessment of insulin resistance (HOMA-IR) and the hepatic insulin resistance index (HIR) increased during overfeeding. Liver fat increased in men. However, grape polyphenol supplementation did not modify the metabolic and anthropometric parameters or counteract the changes during overfeeding, neither in men nor in women. Polyphenol intake was associated with a reduction in adipocyte size in women femoral fat. Grape polyphenol supplementation did not counteract the moderated metabolic alterations induced by one month of high calorie-high fructose overfeeding in men and women. The clinical trials are registered under the numbers NCT02145780 and NCT02225457 at ClinicalTrials.gov and available at https://clinicaltrials.gov/ct2/show/NCT02145780 and https://clinicaltrials.gov/ct2/show/NCT02225457., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Segrestin, Delage, Nemeth, Seyssel, Disse, Nazare, Lambert-Porcheron, Meiller, Sauvinet, Chanon, Simon, Ratiney, Beuf, Pralong, Yassin, Boizot, Gachet, Burton-Pimentel, Vidal, Meugnier, Vionnet and Laville.)

Objective: Bariatric surgery (BS) induces loss of body fat mass (FM) with an inexorable loss of lean mass (LM). Menopause leads to deleterious changes in body composition (BC) related to estrogen deficiency including LM loss and increase in total and visceral adipose tissue (VAT). This study aims to describe the long-term weight evolution of post-menopausal women after Roux-en-Y gastric bypass (RYGB) and to compare the BC between BS patients vs post-menopausal non-operated women., Design: Cross-sectional study of 60 post-menopausal women who underwent RYGB ≥2 years prior to the study with nested case-control design., Methods: Post-menopausal BS women were matched for age and BMI with controls. Both groups underwent DXA scan, lipids and glucose metabolism markers assessment., Results: Median follow-up was 7.5 (2-18) years. Percentage of total weight loss (TWL%) was 28.5 ± 10%. After RYGB, LM percentage of body weight (LM%) was positively associated with TWL% and negatively associated with nadir weight. Forty-one post-BS women were age- and BMI-matched with controls. Post-BS patients showed higher LM% (57.7% (±8%) vs 52.5% (±5%), P = 0.001), reduced FM% (39.4% (±8.4%) vs 45.9% (±5.4%), P < 0.01) and lower VAT (750.6 g (±496) vs 1295.3 g (±688), P < 0.01) with no difference in absolute LM compared to controls. While post-BS women showed a better lipid profile compared to controls, no difference was found in glucose markers., Conclusions: Post-menopausal women after RYGB have a lower FM and VAT, preserved LM and a better lipid profile compared to controls. Weight loss after RYGB seems to have a persistent positive impact on metabolic health.

Introduction: Lipedema is a poorly known condition. Diagnosis is based almost exclusively on clinical criteria, which may be subjective and not always reliable. This study aimed to investigate regional body composition (BC) by dual-energy X-ray absorptiometry (DXA) in patients with lipedema and healthy controls and to determine cut-off values of fat mass (FM) indices to provide an additional tool for the diagnosis and staging of this condition., Methods: This study is a single-center case-control study performed at Lausanne University Hospital, Switzerland. Women with clinically diagnosed lipedema underwent regional BC assessment by DXA. The control group without clinical lipedema was matched for age and body mass index (BMI) at a ratio of 1:2 and underwent similar examination. Regional FM (legs, arms, legs and arms, trunk, android and gynoid FM) was measured in (kg) and divided by FM index (FMI) (kg/m2) and total FM (kg). The trunk/legs and android/gynoid ratios were calculated. For all indices of FM distribution showing a significant difference between cases and controls, we defined the receiver operating characteristic (ROC) curves, calculating the area under the curve (AUC), sensitivity, specificity, and Youden's index. Types and stages of lipedema were compared in terms of FM indices. Correlation analyses between all FM distribution indices and lipedema stages were performed., Results: We included 222 women (74 with lipedema and 148 controls). Overall, the mean age was 41 years (standard deviation [SD] 11), and mean BMI was 30.9 kg/m2 (SD 7.6). A statistically significant difference was observed for all DXA-derived indices of FM distribution between groups, except for arm FM indices. The ROC curve analysis of leg FM/total FM, as a potential indicator of lipedema, resulted in an AUC of 0.90 (95% confidence interval 0.86-0.94). According to Youden's index, optimal cut-off value identifying lipedema was 0.384. Sensitivity and specificity were 0.95 and 0.73, respectively. We found no significant differences between lipedema types and stages in terms of FM indices, nor significant correlations between the latter and lipedema stages., Discussion/conclusion: BC assessment by DXA, and particularly calculation of the leg FM/total FM index, is a simple tool that may help clinicians rule out lipedema in doubtful cases., (© 2022 The Author(s). Published by S. Karger AG, Basel.)

Scope: Combining different "omics" data types in a single, integrated analysis may better characterize the effects of diet on human health., Methods and Results: The performance of two data integration tools, similarity network fusion tool (SNFtool) and Data Integration Analysis for Biomarker discovery using Latent variable approaches for "Omics" (DIABLO; MixOmics), in discriminating responses to diet and metabolic phenotypes is investigated by combining transcriptomics and metabolomics datasets from three human intervention studies: a postprandial crossover study testing dairy foods (n = 7; study 1), a postprandial challenge study comparing obese and non-obese subjects (n = 13; study 2); and an 8-week parallel intervention study that assessed three diets with variable lipid content on fasting parameters (n = 39; study 3). In study 1, combining datasets using SNF or DIABLO significantly improve sample classification. For studies 2 and 3, the value of SNF integration depends on the dietary groups being compared, while DIABLO discriminates samples well but does not perform better than transcriptomic data alone., Conclusion: The integration of associated "omics" datasets can help clarify the subtle signals observed in nutritional interventions. The performance of each integration tool is differently influenced by study design, size of the datasets, and sample size., (© 2021 Wiley-VCH GmbH.)

The characterization of volatile compounds in biological fluids offers a distinct approach to study the metabolic imprint of foods on the human metabolome, particularly to identify novel biomarkers of food intake (BFIs) that are not captured by classic metabolomics. Using a combination of dynamic headspace vacuum transfer In Trap extraction and gas chromatography coupled with mass spectrometry, we measured volatile compounds (the "volatilome") in plasma and urine samples from a randomized controlled crossover intervention study in which 11 healthy subjects ingested milk, cheese, or a soy-based drink. More than 2000 volatile compounds were detected in plasma, while 1260 compounds were detected in urine samples. A postprandial response in plasma was confirmed for 697 features. Univariate and multivariate analyses identified four molecules in plasma and 31 molecules in urine samples differentiating the ingestion of the foods, of which three metabolites in plasma and nine in urine were specific to the dairy products. Among these molecules, heptan-2-one, 3,5-dimethyloctan-2-one, and undecan-2-one in plasma and 3-ethylphenol, heptan-2-one, 1-methoxy-2-propyl acetate, and 9-decenoic acid were highly discriminative for dairy or cheese intake. In urine, 22 volatile compounds were highly discriminative for soy-based drink intake. The majority of these molecules have not been reported in humans. Our findings highlight the potential of plasma and urinary volatilomics for detection of novel dietary biomarkers.

Background: The use of biomarkers of food intake (BFIs) in blood and urine has shown great promise for assessing dietary intake and complementing traditional dietary assessment tools whose use is prone to misreporting., Objective: Untargeted LC-MS metabolomics was applied to identify candidate BFIs for assessing the intake of milk and cheese and to explore the metabolic response to the ingestion of these foods., Methods: A randomized controlled crossover study was conducted in healthy adults [5 women, 6 men; age: 23.6 ± 5.0 y; BMI (kg/m2): 22.1 ± 1.7].  After a single isocaloric intake of milk (600 mL), cheese (100 g), or soy-based drink (600 mL), serum and urine samples were collected postprandially up to 6 h and after fasting after 24 h. Untargeted metabolomics was conducted using LC-MS. Discriminant metabolites were selected in serum by multivariate statistical analysis, and their mass distribution and postprandial kinetics were compared., Results: Serum metabolites discriminant for cheese intake had a significantly lower mass distribution than metabolites characterizing milk intake (P = 4.1 × 10-4). Candidate BFIs for milk or cheese included saccharides, a hydroxy acid, amino acids, amino acid derivatives, and dipeptides. Two serum oligosaccharides, blood group H disaccharide (BGH) and Lewis A trisaccharide (LeA), specifically reflected milk intake but with high interindividual variability. The 2 oligosaccharides showed related but opposing trends: subjects showing an increase in either oligosaccharide did not show any increase in the other oligosaccharide. This result was confirmed in urine., Conclusions: New candidate BFIs for milk or cheese could be identified in healthy adults, most of which were related to protein metabolism. The increase in serum of LeA and BGH after cow-milk intake in adults calls for further investigations considering the beneficial health effects on newborns of such oligosaccharides in maternal milk. The trial is registered at clinicaltrials.gov as NCT02705560., (Copyright © The Author(s) 2020.)

Trimethylamine- N -oxide (TMAO) can be produced by the gut microbiota from dietary substrates and is associated with cardiovascular disease. While dairy products contain TMAO precursors, the effect of fermented dairy on TMAO metabolism remains unclear. We used plasma and urine samples collected for two randomised cross-over studies to evaluate the effects of fermented dairy consumption on TMAO metabolism. In Study 1, thirteen healthy young men tested a yogurt and an acidified milk during postprandial tests and a two-week daily intervention. In Study 2, ten healthy adults tested milk and cheese during postprandial tests. TMAO and five related metabolites were measured in plasma and urine by LC-MS/MS and NMR. Faecal microbiota composition was assessed in Study 1 (16S rRNA metagenomics sequencing). Fermented milk products were associated with lower postprandial TMAO responses than non-fermented milks in urine (Study 1, p = 0.01; Study 2, p = 0.02) and in plasma, comparing yogurt and acidified milk (Study 1, p = 0.04). Daily consumption of dairy products did not differentially affect fasting TMAO metabolites. Significant correlations were observed between microbiota taxa and circulating or urinary TMAO concentrations. Fermentation of dairy products appear, at least transiently, to affect associations between dairy products and circulating TMAO levels.

Background: Lactase is an enzyme that hydrolyzes lactose into glucose and galactose in the small intestine, where they are absorbed. Hypolactasia is a common condition, primarily caused by genetic programming, that leads to lactose maldigestion and, in certain cases, lactose intolerance. Galactitol and galactonate are 2 products of hepatic galactose metabolism that are candidate markers for the intake of lactose-containing foods., Objectives: The primary objective of the study was to explore the changes in serum and urine metabolomes during postprandial dairy product tests through the association between lactase persistence genotype and the postprandial dynamics of lactose-derived metabolites., Methods: We characterized the 6-h postprandial serum kinetics and urinary excretion of lactose, galactose, galactitol, and galactonate in 14 healthy men who had consumed a single dose of acidified milk (800 g) which contained 38.8 g lactose. Genotyping of LCT-13910 C/T (rs4988235) was performed to assess primary lactase persistence., Results: There were 2 distinct postprandial responses, classified as high and low metabolite responses, observed for galactose, and its metabolites galactitol and galactonate, in serum and urine. In all but 1 subject, there was a concordance between the high metabolite responses and genetic lactase persistence and between the low metabolite responses and genetic lactase nonpersistence (accuracy 0.92), galactitol and galactonate being more discriminative than galactose., Conclusions: Postprandial galactitol and galactonate after lactose overload appear to be good proxies for genetically determined lactase activity. The development of a noninvasive lactose digestion test based on the measurement of these metabolites in urine could be clinically useful. This trial was registered at clinicaltrials.gov as NCT02230345.

Background: Fermentation is a widely used method of natural food preservation that has consequences on the nutritional value of the transformed food. Fermented dairy products are increasingly investigated in view of their ability to exert health benefits beyond their nutritional qualities., Objective: To explore the mechanisms underpinning the health benefits of fermented dairy intake, the present study followed the effects of milk fermentation, from changes in the product metabolome to consequences on the human serum metabolome after its ingestion., Methods: A randomized crossover study design was conducted in 14 healthy men [mean age: 24.6 y; mean body mass index (in kg/m2): 21.8]. At the beginning of each test phase, serum samples were taken 6 h postprandially after the ingestion of 800 g of a nonfermented milk or a probiotic yogurt. During the 2-wk test phases, subjects consumed 400 g of the assigned test product daily (200 g, 2 times/d). Serum samples were taken from fasting participants at the end of each test phase. The serum metabolome was assessed through the use of LC-MS-based untargeted metabolomics., Results: Postprandial serum metabolomes after milk or yogurt intake could be differentiated [orthogonal projections to latent structures discriminant analysis (OPLS-DA) Q2 = 0.74]. Yogurt intake was characterized by higher concentrations of 7 free amino acids (including proline, P = 0.03), reduced concentrations of 5 bile acids (including glycocholic acid, P = 0.04), and modulation of 4 indole derivative compounds (including indole lactic acid, P = 0.01). Fasting serum samples after 2 wk of daily intake of milk or yogurt could also be differentiated based on their metabolic profiles (OPLS-DA Q2 = 0.56) and were discussed in light of the postprandial results., Conclusion: Metabolic pathways related to amino acids, indole derivatives, and bile acids were modulated in healthy men by the intake of yogurt. Further investigation to explore novel health effects of fermented dairy products is warranted.This trial was registered at clinicaltrials.gov as NCT02230345.

The identification and validation of food intake biomarkers (FIBs) in human biofluids is a key objective for the evaluation of dietary intake. We report here the analysis of the GC-MS and 1H-NMR metabolomes of serum samples from a randomized cross-over study in 11 healthy volunteers having consumed isocaloric amounts of milk, cheese, and a soy drink as non-dairy alternative. Serum was collected at baseline, postprandially up to 6 h, and 24 h after consumption. A multivariate analysis of the untargeted serum metabolomes, combined with a targeted analysis of candidate FIBs previously reported in urine samples from the same study, identified galactitol, galactonate, and galactono-1,5-lactone (milk), 3-phenyllactic acid (cheese), and pinitol (soy drink) as candidate FIBs for these products. Serum metabolites not previously identified in the urine samples, e.g., 3-hydroxyisobutyrate after cheese intake, were detected. Finally, an analysis of the postprandial behavior of candidate FIBs, in particular the dairy fatty acids pentadecanoic acid and heptadecanoic acid, revealed specific kinetic patterns of relevance to their detection in future validation studies. Taken together, promising candidate FIBs for dairy intake appear to be lactose and metabolites thereof, for lactose-containing products, and microbial metabolites derived from amino acids, for fermented dairy products such as cheese., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, and in the decision to publish the results.

The metabolic health benefits of fermented milks have already been investigated using clinical biomarkers but the development of transcriptomic analytics in blood offers an alternative approach that may help to sensitively characterise such effects. We aimed to assess the effects of probiotic yoghurt intake, compared to non-fermented, acidified milk intake, on clinical biomarkers and gene expression in peripheral blood. To this end, a randomised, crossover study was conducted in fourteen healthy, young men to test the two dairy products. For a subset of seven subjects, RNA sequencing was used to measure gene expression in blood collected during postprandial tests and after two weeks daily intake. We found that the postprandial response in insulin was different for probiotic yoghurt as compared to that of acidified milk. Moreover changes in several clinical biomarkers were associated with changes in the expression of genes representing six metabolic genesets. Assessment of the postprandial effects of each dairy product on gene expression by geneset enrichment analysis revealed significant, similar modulation of inflammatory and glycolytic genes after both probiotic yoghurt and acidified milk intake, although distinct kinetic characteristics of the modulation differentiated the dairy products. The aryl hydrocarbon receptor was a major contributor to the down-regulation of the inflammatory genesets and was also positively associated with changes in circulating insulin at 2h after yoghurt intake (p = 0.05). Daily intake of the dairy products showed little effect on the fasting blood transcriptome. Probiotic yoghurt and acidified milk appear to affect similar gene pathways during the postprandial phase but differences in the timing and the extent of this modulation may lead to different physiological consequences. The functional relevance of these differences in gene expression is supported by their associations with circulating biomarkers.

The absence of a dedicated transport for disaccharides in the intestine implicates that the metabolic use of dietary lactose relies on its prior hydrolysis at the intestinal brush border. Consequently, lactose in blood or urine has mostly been associated with specific cases in which the gastrointestinal barrier is damaged. On the other hand, lactose appears in the blood of lactating women and has been detected in the blood and urine of healthy men, indicating that the presence of lactose in the circulation of healthy subjects is not incompatible with normal physiology. In this cross-over study we have characterised the postprandial kinetics of lactose, and its major constituent, galactose, in the serum of fourteen healthy men who consumed a unique dose of 800 g milk or yogurt. Genetic testing for lactase persistence and microbiota profiling of the subjects were also performed. Data revealed that lactose does appear in serum after dairy intake, although with delayed kinetics compared with galactose. Median serum concentrations of approximately 0·02 mmol/l lactose and approximately 0·2 mmol/l galactose were observed after the ingestion of milk and yogurt respectively. The serum concentrations of lactose were inversely correlated with the concentrations of galactose, and the variability observed between the subjects' responses could not be explained by the presence of the lactase persistence allele. Finally, lactose levels have been associated with the abundance of the Veillonella genus in faecal microbiota. The measurement of systemic lactose following dietary intake could provide information about lactose metabolism and nutrient transport processes under normal or pathological conditions.

The measurement of food intake biomarkers (FIBs) in biofluids represents an objective tool for dietary assessment. FIBs of milk and cheese still need more investigation due to the absence of candidate markers. Thus, an acute intervention study has been performed to sensitively and specifically identify candidate FIBs. Eleven healthy male and female volunteers participated in the randomized, controlled crossover study that tested a single intake of milk and cheese as test products, and soy-based drink as a control. Urine samples were collected at baseline and up to 24 h at distinct time intervals (0-1, 1-2, 2-4, 4-6, 6-12, and 12-24 h) and were analyzed using an untargeted multiplatform approach (GC-MS and 1 H NMR). Lactose, galactose, and galactonate were identified exclusively after milk intake while for other metabolites (allantoin, hippurate, galactitol, and galactono-1,5-lactone) a significant increase has been observed. Urinary 3-phenyllactic acid was the only compound specifically reflecting cheese intake although alanine, proline, and pyroglutamic acid were found at significantly higher levels after cheese consumption. In addition, several novel candidate markers for soy drink were identified, such as pinitol and trigonelline. Together, these candidate FIBs of dairy intake could serve as a basis for future validation studies under free-living conditions.

Probiotic yogurt and milk supplemented with probiotics have been investigated for their role in 'low-grade' inflammation but evidence for their efficacy is inconclusive. This study explores the impact of probiotic yogurt on metabolic and inflammatory biomarkers, with a parallel study of gut microbiota dynamics. The randomised cross-over study was conducted in fourteen healthy, young men to test probiotic yogurt compared with milk acidified with 2 % d-(+)-glucono-δ-lactone during a 2-week intervention (400 g/d). Fasting assessments, a high-fat meal test (HFM) and microbiota analyses were used to assess the intervention effects. Baseline assessments for the HFM were carried out after a run-in during which normal milk was provided. No significant differences in the inflammatory response to the HFM were observed after probiotic yogurt compared with acidified milk intake; however, both products were associated with significant reductions in the inflammatory response to the HFM compared with the baseline tests (assessed by IL6, TNFα and chemokine ligand 5) (P<0·001). These observations were accompanied by significant changes in microbiota taxa, including decreased abundance of Bilophila wadsworthia after acidified milk (log 2-fold-change (FC)=-1·5, P adj=0·05) and probiotic yogurt intake (FC=-1·3, P adj=0·03), increased abundance of Bifidobacterium species after acidified milk intake (FC=1·4, P adj=0·04) and detection of Lactobacillus delbrueckii spp. bulgaricus (FC=7·0, P adj<0·01) and Streptococcus salivarius spp. thermophilus (FC=6·0, P adj<0·01) after probiotic yogurt intake. Probiotic yogurt and acidified milk similarly reduce postprandial inflammation that is associated with a HFM while inducing distinct changes in the gut microbiota of healthy men. These observations could be relevant for dietary treatments that target 'low-grade' inflammation.

Context: Obesity is associated with neuroendocrine reproductive alterations and decreased fertility., Objective: The objective of the study was to gain insight into the neuroendocrine mechanisms implicated in these alterations., Design: The effects on pulsatile LH secretion of 28 days of a hypercaloric diet were studied in lean and regularly cycling female volunteers. Approximately 50% extra calories (3 g sucrose/kg body weight per day and 1 g fat/kg body weight per day) were added to their individual daily requirements. Spontaneous and insulin-stimulated LH secretion was recorded on 2 different days, before and at the end of the caloric load., Results: The hypercaloric diet induced an average weight gain of 2.0 ± 0.3 kg (P < .05), corresponding to a body mass index increase of 0.7 ± 0.1 kg/m(2) (P < .05). A concomitant decrease of 11.6% ± 4.6% in whole-body insulin sensitivity was also observed (δ = -1.6 ± 0.7 mg/kg · min glucose; P < .05). The frequency of spontaneous and insulin-stimulated pulsatile LH secretion was increased by 17.9% ± 9.0% and 26.5% ± 9.0%, respectively (both P < .05). Spontaneous LH peak amplitude was decreased by 26.5% ± 9.0% (δ = -0.7 ± 0.36 U/L; P < .05), a change correlated with insulin sensitivity., Conclusions: Short-term weight gain in normal female volunteers induces alterations of LH secretion reminiscent to those observed in obesity. A decrease in insulin sensitivity may constitute a mechanistic link between obesity and its associated neuroendocrine dysfunctions.

Bariatric surgery has become the treatment of choice for severe obesity. The significant weight loss induced by these procedures is accompanied by spectacular improvements in the metabolic comorbidities that participate in morbidity and mortality of obesity. However, several questions remain open regarding the identification of patients that will benefit the most from the intervention or the long-term outcomes in terms of weight and co-morbidities. The Cohort obesity of Lausanne was initiated in order to try and answer some of these questions, and more specifically to identify predictive factors of long-term response to gastric by-pass.

Postprandial inflammation is an important factor for human health since chronic low-grade inflammation is associated with chronic diseases. Dairy products have a weak but significant anti-inflammatory effect on postprandial inflammation. The objective of the present study was to compare the effect of a high-fat dairy meal (HFD meal), a high-fat non-dairy meal supplemented with milk (HFM meal) and a high-fat non-dairy control meal (HFC meal) on postprandial inflammatory and metabolic responses in healthy men. A cross-over study was conducted in nineteen male subjects. Blood samples were collected before and 1, 2, 4 and 6 h after consumption of the test meals. Plasma concentrations of insulin, glucose, total cholesterol, LDL-cholesterol, HDL-cholesterol, TAG and C-reactive protein (CRP) were measured at each time point. IL-6, TNF-α and endotoxin concentrations were assessed at baseline and endpoint (6 h). Time-dependent curves of these metabolic parameters were plotted, and the net incremental AUC were found to be significantly higher for TAG and lower for CRP after consumption of the HFM meal compared with the HFD meal; however, the HFM and HFD meals were not different from the HFC meal. Alterations in IL-6, TNF-α and endotoxin concentrations were not significantly different between the test meals. The results suggest that full-fat milk and dairy products (cheese and butter) have no significant impact on the inflammatory response to a high-fat meal.

A dose-response strategy may not only allow investigation of the impact of foods and nutrients on human health but may also reveal differences in the response of individuals to food ingestion based on their metabolic health status. In a randomized crossover study, we challenged 19 normal-weight (BMI: 20-25 kg/m(2)) and 18 obese (BMI: >30 kg/m(2)) men with 500, 1000, and 1500 kcal of a high-fat (HF) meal (60.5% energy from fat). Blood was taken at baseline and up to 6 h postprandially and analyzed for a range of metabolic, inflammatory, and hormonal variables, including plasma glucose, lipids, and C-reactive protein and serum insulin, glucagon-like peptide-1, interleukin-6 (IL-6), and endotoxin. Insulin was the only variable that could differentiate the postprandial response of normal-weight and obese participants at each of the 3 caloric doses. A significant response of the inflammatory marker IL-6 was only observed in the obese group after ingestion of the HF meal containing 1500 kcal [net incremental AUC (iAUC) = 22.9 ± 6.8 pg/mL × 6 h, P = 0.002]. Furthermore, the net iAUC for triglycerides significantly increased from the 1000 to the 1500 kcal meal in the obese group (5.0 ± 0.5 mmol/L × 6 h vs. 6.0 ± 0.5 mmol/L × 6 h; P = 0.015) but not in the normal-weight group (4.3 ± 0.5 mmol/L × 6 h vs. 4.8 ± 0.5 mmol/L × 6 h; P = 0.31). We propose that caloric dose-response studies may contribute to a better understanding of the metabolic impact of food on the human organism. This study was registered at clinicaltrials.gov as NCT01446068., (© 2014 American Society for Nutrition.)

Background: The etiology of diabetic nephropathy depends partly on genetic factors. Elevated systemic and intraglomerular blood pressure and glomerular filtration rate, partly regulated by the renin-angiotensin system, increase the risk of diabetic nephropathy., Methods: The present case-control study investigated the association of the rs5186 polymorphism, in the angiotensin II type 1 receptor gene (AGTR1), with diabetic nephropathy. The study included 3561 patients with type 1 diabetes from Denmark, Finland, France and Sweden. Microalbuminuria was defined as albumin excretion rate (AER) ≥20 to <200 μg/min or albumin concentration ≥30 to <300 mg/l (n=707), macroalbuminuria was defined as AER≥200 μg/min or ≥300 mg/l (n=1546), and patients with renal replacement therapy were also included in this group. The controls had >15 years diabetes duration, AER <20 μg/min or <30 mg/l, and no antihypertensive treatment (n=1308)., Results: AA genotype of the rs5186 polymorphism significantly increased the risk of diabetic nephropathy in male patients, OR=1.27 (95% CI=1.02-1.58), P=0.03, adjusted for age at diabetes onset, HbA1c, diabetes duration, smoking and country of origin. Among the women, there were no significant associations between rs5186 and diabetic nephropathy, OR=0.89 (0.71-1.11), P=0.30., Conclusion: We conclude that the AGTR1 gene may be associated with increased risk of diabetic nephropathy in men with type 1 diabetes., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Hyperglycaemia in diabetes mellitus (DM) alters gene expression regulation in various organs and contributes to long term vascular and renal complications. We aimed to generate novel renal genome-wide gene transcription data in rat models of diabetes in order to test the responsiveness to hyperglycaemia and renal structural changes of positional candidate genes at selected diabetic nephropathy (DN) susceptibility loci., Methods: Both Affymetrix and Illumina technologies were used to identify significant quantitative changes in the abundance of over 15,000 transcripts in kidney of models of spontaneous (genetically determined) mild hyperglycaemia and insulin resistance (Goto-Kakizaki-GK) and experimentally induced severe hyperglycaemia (Wistar-Kyoto-WKY rats injected with streptozotocin [STZ])., Results: Different patterns of transcription regulation in the two rat models of diabetes likely underlie the roles of genetic variants and hyperglycaemia severity. The impact of prolonged hyperglycaemia on gene expression changes was more profound in STZ-WKY rats than in GK rats and involved largely different sets of genes. These included genes already tested in genetic studies of DN and a large number of protein coding sequences of unknown function which can be considered as functional and, when they map to DN loci, positional candidates for DN. Further expression analysis of rat orthologs of human DN positional candidate genes provided functional annotations of known and novel genes that are responsive to hyperglycaemia and may contribute to renal functional and/or structural alterations., Conclusion: Combining transcriptomics in animal models and comparative genomics provides important information to improve functional annotations of disease susceptibility loci in humans and experimental support for testing candidate genes in human genetics.

Objective: Genetic and environmental factors modulate the susceptibility to diabetic nephropathy, as initiating and/or progression factors. The objective of the European Rational Approach for the Genetics of Diabetic Complications (EURAGEDIC) study is to identify nephropathy susceptibility genes. We report molecular genetic studies for 127 candidate genes for nephropathy., Research Design and Methods: Polymorphisms were identified through sequencing of promoter, exon, and flanking intron gene regions and a database search. A total of 344 nonredundant SNPs and nonsynonymous variants were tested for association with diabetic nephropathy (persistent albuminuria >/=300 mg/24 h) in a large type 1 diabetes case/control (1,176/1,323) study from three European populations., Results: Only one SNP, rs2281999, located in the UNC13B gene, was significantly associated with nephropathy after correction for multiple testing. Analyses of 21 additional markers fully characterizing the haplotypic variability of the UNC13B gene showed consistent association of SNP rs13293564 (G/T) located in intron 1 of the gene with nephropathy in the three populations. The odds ratio (OR) for nephropathy associated with the TT genotype was 1.68 (95% CI 1.29-2.19) (P = 1.0 x 10(-4)). This association was replicated in an independent population of 412 case subjects and 614 control subjects (combined OR of 1.63 [95% CI 1.30-2.05], P = 2.3 x 10(-5))., Conclusions: We identified a polymorphism in the UNC13B gene associated with nephropathy. UNC13B mediates apopotosis in glomerular cells in the presence of hyperglycemia, an event occurring early in the development of nephropathy. We propose that this polymorphism could be a marker for the initiation of nephropathy. However, further studies are needed to clarify the role of UNC13B in nephropathy.

Adiponectin levels are increased in patients with type I diabetes especially in the presence of microangiopathy. Here we determined the predictive value of serum adiponectin levels and 8 adiponectin gene polymorphisms for mortality, cardiovascular events and end-stage renal disease in type I diabetic patients. This prospective, observational follow-up study of type I diabetics consisted of 438 patients with overt diabetic nephropathy that were compared to 440 type I patients with normal albumin excretion. These two groups were followed an average of 8 years and generally matched for gender, age and duration of diabetes. Cox regression analysis of 373 patients showed a covariate-adjusted hazard ratio for all-cause mortality of 1.46 for a change of one standard deviation in log10 of serum adiponectin. There was no association with cardiovascular events; however, serum adiponectin levels predicted end stage renal disease in a covariate-adjusted analysis. Two of eight gene polymorphisms, found in the 878 patients, were associated with increased serum adiponectin levels but none of the polymorphisms were associated with a renal or cardiovascular outcome. These studies show that high serum adiponectin levels predict mortality and progression to end stage renal disease in type I diabetic patients.

Background: Diabetic nephropathy is likely to be a complex genetic trait. To date, most diabetic nephropathy candidate gene studies have tested a limited number of genes and variants in small sized populations, or in populations that were poorly matched or phenotyped. The main objective of the EURAGEDIC study was to address these problems., Methods: Single nucleotide polymorphisms (SNPs) in candidate genes were tested for association with overt diabetic nephropathy (persistent albuminuria >300 mg/24 h) in a large (n=2499) Type 1 diabetes case/control study. Testing for transmission disequilibrium in 541 independent parent-offspring trios with or without diabetic nephropathy was applied for validation of consistency. Candidate genes were selected based on previous linkage studies, knowledge of metabolic pathways, and animal models. A comprehensive SNP discovery in more than 100 candidate genes was performed by direct sequencing., Results: In total, 1176 cases with diabetic nephropathy and 1323 diabetic controls with longstanding normoalbuminuria were included from three European populations (Denmark, Finland, France). Data were collected on HbA(1c), blood pressure, urinary albumin excretion rate, kidney function, retinopathy, smoking, medication and cardiovascular disease. To summarize the relevant non-genetic predictors for diabetic nephropathy a baseline phenotypic model fitted to EURAGEDIC data included the covariates: sex, diabetes duration, HbA(1c) and smoking as well as pair-wise interactions., Conclusions: The EURAGEDIC study is designed and powered to identify and validate common alleles as genetic risk factors for diabetic nephropathy in Type 1 diabetic patients.

Angiotensin 1-converting enzyme gene (ACE) is a risk factor for diabetic nephropathy (DN) in patients with type 1 diabetes. The selection of this candidate gene is supported by cross-sectional and follow-up studies, but no convincing family-based studies are available. Recruited were 1057 patients (with DN: persistent albuminuria with or without renal failure) and 1127 control subjects (long-standing [> or =15 yr] normoalbuminuric patients with type 1 diabetes) in Denmark, Finland, and France and 532 family trios that were composed of 244 trios with DN probands and 288 trios with non-DN probands. Five ACE polymorphisms were studied. In the case-control analysis, the rs1800764-C, rs4311-T, Insertion/deletion (I/D or rs1799752)-D, rs4366-G, and rs12449782-G alleles were associated with an increased risk for DN, homogeneously across populations, with allelic odds ratios of 1.11 (95% confidence interval 1.00 to 1.22), 1.18 (1.04 to 1.33), 1.13 (1.02 to 1.23), 1.10 (0.99 to 1.20), and 1.12 (1.01 to 1.23), respectively. Haplotype analysis further demonstrated that the haplotype defined by the D, rs4366&#95;G and rs12449782&#95;G alleles was associated with a greater risk for DN. Even though no significant allelic overtransmission to DN or non-DN probands was detected, the family-based study provided consistent results with the case-control analysis. In a large case-control study, it was shown that the ACE polymorphisms were associated with DN; these findings were not confirmed in a family-based association study. This study population is suitable to search for additional candidate genes for DN.

Type II SH2 domain-containing inositol 5-phosphatase (INPPL1, or SHIP2) plays an important role in the control of insulin sensitivity. INPPL1 mutations affecting gene function have been found in rat models of type 2 diabetes and hypertension and in type 2 diabetic patients. We investigated the influence of nucleotide variation in INPPL1 on components of the metabolic syndrome. Following comprehensive resequencing of the gene, we genotyped 12 informative polymorphisms in 1,304 individuals from 424 British type 2 diabetes families that were characterized for several metabolic phenotypes. We have found highly significant associations of single nucleotide polymorphisms (SNPs) and haplotypes of INPPL1 with hypertension as well as with other components of the metabolic syndrome. In a cohort of 905 French type 2 diabetic patients, we found evidence of association of INPPL1 SNPs with the presence of hypertension. We conclude that INPPL1 variants may impact susceptibility to disease and/or to subphenotypes involved in the metabolic syndrome in some diabetic patients.

Type 2 diabetes is a heterogeneous disorder of glucose metabolism characterized by insulin resistance, beta-cell dysfunction, and increased glucose production by the liver. Given the high degree of genetic heterogeneity, multiple genes with small to moderate effects may influence susceptibility to diabetes. To circumvent this limitation, we searched for quantitative trait loci (QTLs) that explain the variation in susceptibility of type 2 diabetes in a single extended family, as these individuals are likely to share polymorphisms. We collected genotypic and phenotypic data on 152 individuals ascertained through a multimedia campaign in France to find diabetes-prone families for genetic studies. The effects of genes and covariates (age and sex) on diabetes status were estimated using a threshold model and a maximum likelihood variance component approach. We obtained suggestive evidence of linkage (logarithm of odds [LOD] = 2.4) for diabetes status on chromosome 5q. Within the 1-LOD unit support interval, there are two strong candidates: PCSK1 and CAST. Furthermore, we have obtained a replication (LOD = 1.6) for a QTL for type 2 diabetes on chromosome 11 detected by Hanson and colleagues (1998).

Cholecystokinin (CCK) and gastrin (G) and their receptors (CCK1 and CCK2) are involved in multiple physiological functions. Notably, CCK1R plays a role in the regulation of food intake whereas both CCK1R and CCK2R play a role in the regulation of pancreatic endocrine function. CCK1R and CCK2R may therefore serve as pharmacological targets in diabetes and obesity and genes encoding these receptors may be candidate genes in the pathogenesis of the diseases. In this study, we used single nucleotide polymorphism analysis and allele specific amplification for mutation screening of the CCK2 receptor gene and family linkage study. Mutated receptors were constructed, expressed in COS-7 cells for analysis of their binding and functional properties. V125I-CCK2 receptor variant was found in 2 out of 18 type 2 diabetes mellitus families tested. V125I mutation co-segregated in those 2 initial families, but further association studies showed that this mutation was not associated with diabetes or early age at diagnosis of the disease. V125I-CCK2 receptor high affinity sites exhibited a 2-fold enhanced binding affinity for CCK which was correlated to a slightly increased potency in coupling to inositol phosphate production. Since CCK2 receptor is expressed in pancreatic glucagon-producing cells in humans and is involved in secretion of glucagon, an increase of binding affinity of the mutated CCK2 receptor could enhance glucagon secretion in patients bearing V125I mutation. We also characterized a mutant of the CCK1 receptor which was previously identified in an obese patient. This mutant, V365I-CCK1, demonstrated a decreased level of expression (26%) and efficacy (25%) to stimulate inositol phosphates. It can therefore be expected that in humans bearing V365I mutation, decreases in CCK1 receptor expression and coupling efficiency may affect CCK-induced regulation of satiety. Polymorphism or mutations in the CCK receptors may be involved in type 2 diabetes mellitus and obesity. However, further studies are necessary to precisely evaluate this role in humans.

Despite recent advances in the molecular genetics of type 2 diabetes, the majority of susceptibility genes in humans remain to be identified. We therefore conducted a 10-cM genomewide search (401 microsatellite markers) for type 2 diabetes-related traits in 637 members of 143 French pedigrees ascertained through multiple diabetic siblings, to map such genes in the white population. Nonparametric two-point and multipoint linkage analyzes-using the MAPMAKER-SIBS (MLS) and MAXIMUM-BINOMIAL-LIKELIHOOD (MLB) programs for autosomal markers and the ASPEX program for chromosome X markers-were performed with six diabetic phenotypes: diabetes and diabetes or glucose intolerance (GI), as well as with each of the two phenotypes associated with normal body weight (body-mass index<27 kg/m(2)) or early age at diagnosis (<45 years). In a second step, high-resolution genetic mapping ( approximately 2 cM) was performed in regions on chromosomes 1 and 3 loci showing the strongest linkage to diabetic traits. We found evidence for linkage with diabetes or GI diagnosed at age <45 years in 92 affected sib pairs from 55 families at the D3S1580 locus on chromosome 3q27-qter using MAPMAKER-SIBS (MLS = 4.67, P=.000004), supported by the MLB statistic (MLB-LOD=3.43, P=.00003). We also found suggestive linkage between the lean diabetic status and markers APOA2-D1S484 (MLS = 3. 04, P=.00018; MLB-LOD=2.99, P=.00010) on chromosome 1q21-q24. Several other chromosomal regions showed indication of linkage with diabetic traits, including markers on chromosome 2p21-p16, 10q26, 20p, and 20q. These results (a) showed evidence for a novel susceptibility locus for type 2 diabetes in French whites on chromosome 3q27-qter and (b) confirmed the previously reported diabetes-susceptibility locus on chromosome 1q21-q24. Saturation on both chromosomes narrowed the regions of interest down to an interval of <7 cM.

Type 2 diabetes is a polygenic and genetically heterogeneous disease . The age of onset of the disease is usually late and environmental factors may be required to induce the complete diabetic phenotype. Susceptibility genes for diabetes have not yet been identified. Islet-brain-1 (IB1, encoded by MAPK8IP1), a novel DNA-binding transactivator of the glucose transporter GLUT2 (encoded by SLC2A2), is the homologue of the c-Jun amino-terminal kinase-interacting protein-1 (JIP-1; refs 2-5). We evaluated the role of IBi in beta-cells by expression of a MAPK8IP1 antisense RNA in a stable insulinoma beta-cell line. A 38% decrease in IB1 protein content resulted in a 49% and a 41% reduction in SLC2A2 and INS (encoding insulin) mRNA expression, respectively. In addition, we detected MAPK8IP1 transcripts and IBi protein in human pancreatic islets. These data establish MAPK8IP1 as a candidate gene for human diabetes. Sibpair analyses performed on i49 multiplex French families with type 2 diabetes excluded MAPK8IP1 as a major diabetogenic locus. We did, however, identify in one family a missense mutation located in the coding region of MAPK8IP1 (559N) that segregated with diabetes. In vitro, this mutation was associated with an inability of IB1 to prevent apoptosis induced by MAPK/ERK kinase kinase 1 (MEKK1) and a reduced ability to counteract the inhibitory action of the activated c-JUN amino-terminal kinase (JNK) pathway on INS transcriptional activity. Identification of this novel non-maturity onset diabetes of the young (MODY) form of diabetes demonstrates that IB1 is a key regulator of 3-cell function.

We report a study of 10 candidate genes presumably involved in diabetes or insulin resistance or obesity among Pondicherian Tamil Indians, an isolated population with a high prevalence of diabetes. Forty-nine families with at least two affected patients in the sibship (567 individuals) were selected and tested by PCR-RFLP techniques for reported mutations in 10 diabetes or obesity candidate genes: glucagon receptor, insulin receptor substrate 1, insulin receptor, human beta 3 adrenergic receptor, fatty acid binding protein 2, mitochondrial tRNA(Leu(UUR)), sulphonylurea receptor, human uncoupling protein and the glycogen-associated regulatory subunit of protein phosphatase-1. Glucokinase gene was also screened for mutations. No mutations were found in glucokinase, glucagon receptor and mitochondrial genes in any of the 49 probands. Frequencies of polymorphisms at other loci were similar to those reported in Caucasian populations, except for 4 of the loci at which a higher frequency of variants was observed: human beta 3 adrenergic receptor, human uncoupling type 1 protein, fatty acid binding protein 2 and the glycogen-associated regulatory subunit of protein phosphatase-1. However, no evidence of association between any of these gene variants and non-insulin-dependent diabetes mellitus (NIDDM) or quantitative traits related to NIDDM (including body mass index, waist/hip ratio, insulinaemia, glycaemia, triglycerides and total cholesterol) was found in our sample. These results suggest that none of these gene variants commonly found in the Pondicherian Tamil population of South India is a major NIDDM predisposing locus, although it cannot be excluded that they may contribute to the polygenic background of the metabolic syndrome in Pondichery.

Several candidate genes for non-insulin-dependent diabetes mellitus (NIDDM) map on chromosome 20, including the phosphoenolpyruvate carboxykinase gene (PCK1) and one of the maturity onset diabetes of the young genes (MODY1). Thus, we have investigated the entire long arm of chromosome 20. Linkage analyses were conducted in a total sample of 148 NIDDM families (301 NIDDM sib pairs) and in a subset of 42 early onset NIDDM families, where genetic components are likely to play a more important role (55 NIDDM sib pairs diagnosed at or before 45 years of age), using 10 highly polymorphic markers with an average map density of 7.5 cM. Using affected sib pair methods (two-point linkage and multipoint linkage analyses), significant results were obtained with the 20q13 region, in the vicinity of the PCK1 locus, only in the subset of 55 early onset NIDDM sib pairs (multipoint MLS = 2.74, P = 0.0004; MLS = 2.34, P = 0.0009 when using a conservative weighting procedure). Moreover, another region spanning the ribophorin II (RPNII, phospholipase C (PLC1) and adenosine deaminase (ADA) loci suggested linkage with NIDDM (multipoint MLS of 1.81 in all NIDDM sib pairs, P = 0.003; MLS = 1.31, P = 0.012 when using a conservative weighting procedure). Whereas our study suggests the location of a susceptibility locus for early onset NIDDM in the PCK1 gene region, further investigation in larger data sets is required to confirm these results and assess the role of other regions on chromosome 20q in human NIDDM.