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Objective: Vaspin (visceral adipose tissue derived serine protease inhibitor, SERPINA12) is associated with obesity-related metabolic traits, but its causative role is still elusive. The role of genetics in serum vaspin variability to establish its causal relationship with metabolically relevant traits was investigated., Methods: A meta-analysis of genome-wide association studies for serum vaspin from six independent cohorts (N = 7446) was conducted. Potential functional variants of vaspin were included in Mendelian randomization (MR) analyses to assess possible causal pathways between vaspin and homeostasis model assessment and lipid traits. To further validate the MR analyses, data from Genotype-Tissue Expression (GTEx) were analyzed, db/db mice were treated with vaspin, and serum lipids were measured., Results: A total of 468 genetic variants represented by five independent variants (rs7141073, rs1956709, rs4905216, rs61978267, rs73338689) within the vaspin locus were associated with serum vaspin (all p < 5×10 -8 , explained variance 16.8%). MR analyses revealed causal relationships between serum vaspin and triglycerides, low-density lipoprotein, and total cholesterol. Gene expression correlation analyses suggested that genes, highly correlated with vaspin expression in adipose tissue, are enriched in lipid metabolic processes. Finally, in vivo vaspin treatment reduced serum triglycerides in obese db/db mice., Conclusions: The data show that serum vaspin is strongly determined by genetic variants within vaspin, which further highlight vaspin's causal role in lipid metabolism., (© 2023 The Authors. Obesity published by Wiley Periodicals LLC on behalf of The Obesity Society.)

Transforming growth factor beta-1 (TGFβ1) is an adipokine secreted from adipose tissue, placental tissue and immune cells with a role in cell proliferation, cell apoptosis and angiogenic proliferation. The role of TGFβ1 in pregnancy and child growth and the source of cord TGFβ1 are yet unknown. In this study, we sought to clarify the correlation of TGFβ1 levels with parameters of intrauterine growth and child growth during the first year of life, and to determine whether their source is primarily of fetal or maternal origin. Serum samples and anthropometric measurements were obtained from the LIFE Child cohort of 79 healthy mother-child pairs. Measurements were conducted using enzyme-linked immunosorbent assays. Statistical analyses including Mann-Whitney U-test, correlation analyses and linear regression analyses were performed using GraphPad Prism and R. TGFβ1 levels were significantly higher in cord than in maternal serum, suggesting a fetal origin. Multivariate regression analyses revealed strong positive associations between cord TGFβ1 levels at birth and child weight at U6. Furthermore, cord TGFβ1 was significantly correlated with child weight at approximately one year of age. An increase of 10,000 pg/mL in cord TGFβ1 concentrations at birth was associated with a higher body weight of 201 g at roughly one year of age when adjusted for sex.

Adipokines provide an outstanding role in the comprehensive etiology of obesity and may link adipose tissue dysfunction to further metabolic and cardiovascular complications. Although several adipokines have been identified in terms of their physiological roles, many regulatory circuits remain unclear and translation from experimental studies to clinical applications has yet to occur. Nevertheless, due to their complex metabolic properties, adipokines offer immense potential for their use both as obesity-associated biomarkers and as relevant treatment strategies for overweight, obesity and metabolic comorbidities. To provide an overview of the current clinical use of adipokines, this review summarizes clinical studies investigating the potential of various adipokines with respect to diagnostic and therapeutic treatment strategies for obesity and linked metabolic disorders. Furthermore, an overview of adipokines, for which a potential for clinical use has been demonstrated in experimental studies to date, will be presented. In particular, promising data revealed that fibroblast growth factor (FGF)-19, FGF-21 and leptin offer great potential for future clinical application in the treatment of obesity and related comorbidities. Based on data from animal studies or other clinical applications in addition to obesity, adipokines including adiponectin, vaspin, resistin, chemerin, visfatin, bone morphogenetic protein 7 (BMP-7) and tumor necrosis factor alpha (TNF-α) provide potential for human clinical application.

Adipose tissue inflammation and insulin resistance are hallmarks in the development of metabolic diseases resulting from overweight and obesity, such as type 2 diabetes and non-alcoholic fatty liver disease. In obesity, adipocytes predominantly secrete proinflammatory adipokines that further promote adipose tissue dysfunction with negative effects on local and systemic insulin sensitivity. Expression of the serpin vaspin (SERPINA12) is also increased in obesity and type 2 diabetes, but exhibits compensatory roles in inflammation and insulin resistance. This has in part been demonstrated using vaspin-transgenic mice. We here report a new mouse line (h-vaspinTG) with transgenic expression of human vaspin in adipose tissue that reaches vaspin concentrations three orders of magnitude higher than wild type controls (>200 ng/ml). Phenotyping under chow and high-fat diet conditions included glucose-tolerance tests, measurements of energy expenditure and circulating parameters, adipose tissue and liver histology. Also, ex vivo glucose uptake in isolated adipocytes and skeletal muscle was analyzed in h-vaspinTG and littermate controls. The results confirmed previous findings, revealing a strong reduction in diet-induced weight gain, fat mass, hyperinsulinemia, -glycemia and -cholesterolemia as well as fatty liver. Insulin sensitivity in adipose tissue and muscle was not altered. The h-vaspinTG mice showed increased energy expenditure under high fat diet conditions, that may explain reduced weight gain and overall metabolic improvements. In conclusion, this novel human vaspin-transgenic mouse line will be a valuable research tool to delineate whole-body, tissue- and cell-specific effects of vaspin in health and disease., 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 © 2023 Rapöhn, Elias, Weiner, Pujol, Kehr, Chadt, Al-Hasani, Burkhardt, Klöting, Stumvoll, Bosch, Kovacs, Heiker and Breitfeld.)

GRB14/COBLL1 locus has been shown to be associated with body fat distribution (FD), but neither the causal gene nor its role in metabolic diseases has been elucidated. We hypothesize that GRB14/COBLL1 may act as the causal genes for FD-related SNPs (rs10195252 and rs6738627), and that they may be regulated by SNP to effect obesity-related metabolic traits. We genotyped rs10195252 and rs6738627 in 2860 subjects with metabolic phenotypes. In a subgroup of 560 subjects, we analyzed GRB14/COBLL1 gene expression in paired visceral and subcutaneous adipose tissue (AT) samples. Mediation analyses were used to determine the causal relationship between SNPs, AT GRB14/COBLL1 mRNA expression, and obesity-related traits. In vitro gene knockdown of Grb14/Cobll1 was used to test their role in adipogenesis. Both gene expressions in AT are correlated with waist circumference. Visceral GRB14 mRNA expression is associated with FPG and HbA1c. Both SNPs are associated with triglycerides, FPG, and leptin levels. Rs10195252 is associated with HbA1c and seems to be mediated by visceral AT GRB14 mRNA expression. Our data support the role of the GRB14/COBLL1 gene expression in body FD and its locus in metabolic sequelae: in particular, lipid metabolism and glucose homeostasis, which is likely mediated by AT GRB14 transcript levels.

The hepatitis C virus (HCV)-related bovine hepacivirus (BovHepV) can cause acute as well as persistent infections in cattle. The true clinical relevance of the virus is not yet known. As reliable antibody detection methods are lacking and prevalence studies have only been conducted in cattle and few countries to date, the true distribution, genetic diversity, and host range is probably greatly underestimated. In this study, we applied several RT-PCR methods and a nano-luciferase-based immunoprecipitation system (LIPS) assay to analyze bovine serum samples from Bulgaria as well as wild ruminant sera from Germany and the Czech Republic. Using these methods, BovHepV infections were confirmed in Bulgarian cattle, with viral genomes detected in 6.9% and serological reactions against the BovHepV NS3 helicase domain in 10% of bovine serum samples. Genetic analysis demonstrated co-circulation of highly diverse BovHepV strains in Bulgarian cattle, and three novel BovHepV subtypes within the genotype 1 could be defined. Furthermore, application of a nested RT-PCR led to the first description of a BovHepV variant (genotype 2) in a wild ruminant species. The results of this study significantly enhance our knowledge of BovHepV distribution, genetic diversity, and host range.

Small integral membrane protein 10 like 1 (SMIM10L1) was identified by RNA sequencing as the most significantly downregulated gene in Phosphatase and Tensin Homologue (PTEN) knockdown adipose progenitor cells (APCs). PTEN is a tumor suppressor that antagonizes the growth promoting Phosphoinositide 3-kinase (PI3K)/AKT/mechanistic Target of Rapamycin (mTOR) cascade. Diseases caused by germline pathogenic variants in PTEN are summarized as PTEN Hamartoma Tumor Syndrome (PHTS). This overgrowth syndrome is associated with lipoma formation, especially in pediatric patients. The mechanisms underlying this adipose tissue dysfunction remain elusive. We observed that SMIM10L1 downregulation in APCs led to an enhanced adipocyte differentiation in two- and three-dimensional cell culture and increased expression of adipogenesis markers. Furthermore, SMIM10L1 knockdown cells showed a decreased expression of PTEN, pointing to a mutual crosstalk between PTEN and SMIM10L1. In line with these observations, SMIM10L1 knockdown cells showed increased activation of PI3K/AKT/mTOR signaling and concomitantly increased expression of the adipogenic transcription factor SREBP1. We computationally predicted an α-helical structure and membrane association of SMIM10L1. These results support a specific role for SMIM10L1 in regulating adipogenesis, potentially by increasing PI3K/AKT/mTOR signaling, which might be conducive to lipoma formation in pediatric patients with PHTS., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest. The funder had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Purpose: Adipokines may play an important role in the complex etiology of human obesity and its metabolic complications. Here, we analyzed the relationship between 15 adipokines, eating behavior and body-mass index (BMI)., Methods: The study included 557 participants of the Sorbs (62.1% women, 37.9% men) and 3101 participants of the population-based LIFE-Adult cohorts (53.4% women, 46.4% men) who completed the German version of the Three-Factor-Eating Questionnaire to assess the eating behavior types cognitive restraint, disinhibition and hunger. Serum levels of 15 adipokines, including adiponectin, adipocyte fatty acid-binding protein (AFABP), angiopoietin-related growth factor (AGF), chemerin, fibroblast growth factor (FGF)-19, FGF-21, FGF-23, insulin-like growth factor (IGF)-1, interleukin (IL) 10, irisin, progranulin, vaspin, pro-neurotensin (pro-NT), pro-enkephalin (PENK) and leptin were measured. Based on significant correlations between several adipokines with different eating behavior items and BMI, we conducted mediation analyses, considering the eating behavior items as potential mediation variable towards BMI., Results: Here, we found that the positive association between chemerin, AFABP or leptin and BMI in Sorbian women was mediated by higher restraint or disinhibited eating, respectively. Additionally, in Sorbian women, the negative relation between IGF-1 and BMI was mediated by higher disinhibition and the positive link between AGF and BMI by lower disinhibition. In Sorbian men, the negative relationship between PENK and BMI was mediated by lower disinhibition and hunger, whereas the negative relation between IGF-1 and BMI was mediated by higher hunger. In the LIFE-Adult women´s cohort, associations between chemerin and BMI were mediated by decreased hunger or disinhibition, respectively, whereas relations between PENK and BMI were fully mediated by decreased disinhibition., Conclusion: Our study suggests that adipokines such as PENK, IGF-1, chemerin, AGF, AFABP and leptin might affect the development of obesity by directly modifying individual eating behavior. Given the observational nature of the study, future experimental or mechanistic work is warranted., (© 2021. The Author(s).)

Fibroblast growth factor 21 (FGF21) is a regulator of addictive behavior. Increasing evidence suggests an impact of FGF21 on eating behavior, food and drug cravings and on other adipokines like insulin-like growth factor 1 (IGF-1) or adiponectin. We investigated the association of serum FGF21 and genetic variants with aspects of food and drug craving and obesity related metabolic parameters including serum adipokine levels. Standardized questionnaires, blood samples and anthropometric data of the Sorbs cohort ( n = 1046) were analyzed using SPSS. For genetic analyses, the FGF21 -locus ±10 kb was genotyped and analyzed using PLINK. Validation was conducted in a second independent cohort ( n = 704). FGF21 was significantly associated with alcohol and coffee consumption, smoking and eating behavior (disinhibition). We confirmed correlations of FGF21 serum levels with IGF-1, adiponectin, pro-enkephalin, adipocyte fatty-acid-binding protein, chemerin and progranulin. FGF21 genetic variants were associated with anthropometric and metabolic parameters, adipokines, food and drug craving while strongest evidence was seen with low-density lipoprotein cholesterol (LDL-C). We highlight the potential role of FGF21 in food and drug cravings and provide new insights regarding the link of FGF21 with other adipokines as well as with metabolic traits, in particular those related to lipid metabolism (LDL-C).

Subcutaneous (sc) and visceral (vis) adipose tissue (AT) contribute to the variability in pathophysiological consequences of obesity and adverse fat distribution. To gain insights into the molecular mechanisms distinguishing vis and sc fat, we compared the transcriptome during differentiation of immortalized adipocytes from murine epididymal (epi) and inguinal (ing) AT. RNA was extracted on different days of adipogenesis (-2, 0, 2, 4, 6, 8) and analyzed using Clariom™ D mouse assays (Affymetrix) covering >214,900 transcripts in >66,100 genes. Transcript Time Course Analysis revealed 137 differentially expressed genes. The top genes with most divergent expression dynamics included developmental genes like Alx1, Lhx8, Irx1/2, Hoxc10, Hoxa5/10 , and Tbx5/15 . According to pathway analysis the majority of the genes were enriched in pathways related to AT development. Finally, in paired samples of human vis and sc AT ( N = 63), several of these genes exhibited depot-specific variability in expression which correlated closely with body mass index and/or waist-to-hip ratio. In conclusion, intrinsically programmed differences in gene expression patterns during adipogenesis suggest that fat depot specific regulation of adipogenesis contributes to individual risk of obesity., (Copyright © 2020 Breitfeld, Kehr, Müller, Stadler, Böttcher, Blüher, Stumvoll and Kovacs.)

VASPIN, visceral adipose tissue-derived serpin, is an adipokine ameliorating insulin resistance in obesity. Here, we investigated the role of VASPIN and its genetic variants in lipid metabolism. We measured serum VASPIN concentrations by ELISA in 823 metabolically well-characterized Caucasian subjects (Sorbs from Germany). Furthermore, we genotyped 30 representative single nucleotide polymorphisms (SNP) in two independent cohorts with metabolic phenotyping, the Sorbs (N = 823) and Leipzig (N = 919), and conducted genotype-phenotype association analyses. Circulating VASPIN strongly correlated with triacylglycerol levels (TAG; p = 1.079 × 10 -11 ), and moderately with apolipoprotein A1 and low-density lipoprotein cholesterol (p = 0.026). Genetic variants in VASPIN were nominally associated with cholesterol, high-density and low-density lipoprotein (HDL-chol, LDL-chol), lipoprotein A, and apolipoprotein B as well as with TAG and free fatty acids (all p < 0.05 adjusted for age, sex, and body mass index [BMI]). Mendelian randomization analysis using VASPIN SNP as an instrumental variable showed borderline influence of VASPIN on LDL-chol levels (p = 0.05). Associations of VASPIN and its genetic variation with metabolic traits suggest a role of VASPIN in human lipid metabolism., (© 2019 AOCS.)

Treatment with interferon (IFN) has been associated with depressive side effects. Previous neuroimaging studies have provided information about changes in brain activation patterns in patients under treatment with IFN-alpha, but the effect of other IFNs, or the role of the underlying disease, has yet to be clarified. In the present fMRI study, we looked at brain changes after 8 days of IFN-beta treatment in N = =17 healthy volunteers, thus avoiding the possible confound of the effects of underlying pathology in studies of IFN-treated patients with neurological or other medical disorders. We followed a symptom dimensional approach by simultaneously investigating two distinct symptom domains of depressiveness: negative affect (amygdala) and appetitive motivation (ventral striatum). In these early phases of IFN treatment we detected a selective change in neural substrates of appetitive motivation, consistent with the predominant symptomatic change recorded in psychopathology ratings. In contrast, the fMRI phenotype of negative affect, which is known to characterize disorders of affect involving anxiety and depressiveness as well as individual vulnerability to depression, was unchanged after treatment. These findings suggest that IFN may induce an affective syndrome through a mechanism involving down-regulation of appetitive motivation., (Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: The polyphenol resveratrol has been suggested to exert beneficial effects on memory and the aging hippocampus due to calorie-restriction mimicking effects. However, the evidence based on human interventional studies is scarce. We therefore aimed to determine the effects of resveratrol on memory performance, and to identify potential underlying mechanisms using a broad array of blood-based biomarkers as well as hippocampus connectivity and microstructure assessed with ultra-high field magnetic resonance imaging (UHF-MRI)., Methods: In this double-blind, randomized controlled trial, 60 elderly participants (60-79 years) with a wide body-mass index (BMI) range of 21-37 kg/m 2 were randomized to receive either resveratrol (200 mg/day) or placebo for 26 weeks (registered at ClinicalTrials.gov: NCT02621554). Baseline and follow-up assessments included the California Verbal Learning Task (CVLT, main outcome), the ModBent task, anthropometry, markers of glucose and lipid metabolism, inflammation and neurotrophins derived from fasting blood, multimodal neuroimaging at 3 and 7 T, and questionnaires to assess confounding factors., Results: Multivariate repeated-measures ANOVA did not detect significant time by group effects for CVLT performance. There was a trend for preserved pattern recognition memory after resveratrol, while performance decreased in the placebo group (n.s., p = 0.07). Further exploratory analyses showed increases in both groups over time in body fat, cholesterol, fasting glucose, interleukin 6, high sensitive C-reactive protein, tumor necrosis factor alpha and in mean diffusivity of the subiculum and presubiculum, as well as decreases in physical activity, brain-derived neurotrophic factor and insulin-like growth factor 1 at follow-up, which were partly more pronounced after resveratrol., Discussion: This interventional study failed to show significant improvements in verbal memory after 6 months of resveratrol in healthy elderly with a wide BMI range. A non-significant trend emerged for positive effects on pattern recognition memory, while possible confounding effects of unfavorable changes in lifestyle behavior, neurotrophins and inflammatory markers occurred. Our findings also indicate the feasibility to detect (un)healthy aging-related changes in measures of hippocampus microstructure after 6 months using 7T diffusion MRI. More studies incorporating a longer duration and larger sample size are needed to determine if resveratrol enhances memory performance in healthy older adults., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Functional imaging studies of affective disorders have demonstrated abnormal activity in the amygdala in response to emotionally salient stimuli. Since in other studies this response has been shown to habituate during the scanning session, it is not clear if it may be of use in monitoring disease progression or remission, or in monitoring the effects of therapy, as habituation may confound normalisation of response. We investigated here amygdala activation in healthy participants exposed to displays of emotional facial expressions in a sample of N = 31 individuals assessed twice in an interval of three weeks. At this interval no habituation could be detected, suggesting the validity of this imaging assay in repeated assessments of amygdalar reactivity. However, the fusiform gyrus and the inferior frontal lobes showed decreases in activations that may be related to the role of these areas in encoding visual and emotional aspects of the stimuli., Competing Interests: The authors have declared that no competing interests exist.

Objective: The current study investigates potential pathways from socio-economic status (SES) to BMI in the adult population, considering psychological domains of eating behaviour (restrained eating, uncontrolled eating, emotional eating) as potential mediators stratified for sex., Design: Data were derived from the population-based cross-sectional LIFE-Adult-Study. Parallel-mediation models were conducted to obtain the total, direct and indirect effects of psychological eating behaviour domains on the association between SES and BMI for men and for women., Setting: Leipzig, Germany., Subjects: We studied 5935 participants aged 18 to 79 years., Results: Uncontrolled eating mediated the association between SES and BMI in men only and restrained eating in both men and women. Emotional eating did not act as mediator in this relationship. The total effect of eating behaviour domains on the association between SES and BMI was estimated as β=-0·03 (se 0·02; 95 % CI -0·062, -0·003) in men and β=-0·18 (se 0·02; 95 % CI -0·217, -0·138) in women., Conclusions: Our findings do not indicate a strong overall mediation effect of the eating behaviour domains restrained eating, uncontrolled eating and emotional eating on the association between SES and BMI. Further research on other pathways of this association is strongly recommended. Importantly, our findings indicate that, independent from one's social position, focusing on psychological aspects in weight reduction might be a promising approach.

The 'Fragebogen zum Essverhalten' (FEV) is the German version of the Three-factor-Eating-Questionnaire (TFEQ). This questionnaire covers three domains of eating behaviour ('cognitive restraint', 'disinhibition' and 'hunger') as well as common problems (e.g. craving for sweets). So far, there is a lack of normative data of the FEV especially for the middle-aged and older population. Aim of this study therefore was to provide age- and gender-specific norms of the FEV for the general population aged 40-79 years. We studied 3144 participants of the ongoing large community-based Leipzig Research Center for Civilization Diseases (LIFE) Health Care Study. We provided age- (four age groups: 40-49, 50-59, 60-69, and 70-79 years) and gender-specific percentile ranks and T-scores for the three domains of the FEV as well as age- and gender-specific frequencies of the common problems in eating behaviour. Females scored significantly higher than males in all three domains of the FEV (p < 0.001). Older individuals showed significantly higher mean scores than the younger ones in the domain of cognitive restraint, but lower mean scores in disinhibition and hunger (p < 0.001). 45.1% of the males and 69.9% of the females reported specific problems in eating. The main problem in both genders was craving for sweets (38.6%). Eating in response to stress was mostly reported in younger individuals. The present study offers current normative data for the FEV in the middle-aged and older general population that can be applied in clinical and non-clinical settings. Information on eating behaviour can be helpful in understanding body weight modulation, and thus, may help to improve interventive and preventive programmes for overweight, obesity, and eating disorders., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The Three-Factor-Eating-Questionnaire (TFEQ) is an established instrument to assess eating behaviour. Analysis of the TFEQ-factor structure was based on selected, convenient and clinical samples so far. Aims of this study were (I) to analyse the factor structure of the German version of the TFEQ and (II)--based on the refined factor structure--to examine the association between eating behaviour and the body mass index (BMI) in a general population sample of 3,144 middle-aged and older participants (40-79 years) of the ongoing population based cohort study of the Leipzig Research Center for Civilization Diseases (LIFE Health Study). The factor structure was examined in a split-half analysis with both explorative and confirmatory factor analysis. Associations between TFEQ-scores and BMI values were tested with multiple regression analyses controlled for age, gender, and education. We found a three factor solution for the TFEQ with an 'uncontrolled eating', a 'cognitive restraint' and an 'emotional eating' domain including 29 of the original 51 TFEQ-items. Scores of the 'uncontrolled eating domain' showed the strongest correlation with BMI values (partial r = 0.26). Subjects with scores above the median in both 'uncontrolled eating' and 'emotional eating' showed the highest BMI values (mean = 29.41 kg/m²), subjects with scores below the median in all three domains showed the lowest BMI values (mean = 25.68 kg/m²; F = 72.074, p<0.001). Our findings suggest that the TFEQ is suitable to identify subjects with specific patterns of eating behaviour that are associated with higher BMI values. Such information may help health care professionals to develop and implement more tailored interventions for overweight and obese individuals.

Many diseases nowadays are assumed to be genetically determined. Therefore, many knockout mouse models have been established and are widely used. Unfortunately, nutrition (in particular the fat content of food) is often neglected in studies on these disease models. In this study the effects of nutrition on the lipid (triacylglycerol, TAG) compositions of different mouse adipose tissues were investigated. Mice were subjected to different diets [high fat (HF) vs. standard diet (SD)] and different adipose tissue samples (brown, visceral, and subcutaneous fat) were isolated after 12 weeks. Subsequent to lipid extraction, the organic extracts were analyzed by mass spectrometry (MALDI and ESI), high-resolution (1)H and (31)P NMR spectroscopy, high-performance thin-layer chromatography (HPTLC), and gas chromatography (GC). In adipose tissue of mice fed with HF diet, (a) decreased double bond contents and (b) decreased fatty acyl chain lengths of tissue TAGs were observed; this trend could be concomitantly monitored by all methods used. However, the adipose tissue still contained significant amounts of slightly unsaturated fatty acyl residues (18:1). Thus, a certain double bond content seems necessary to maintain the properties of adipose tissues.

Background and Aims: Polymorphisms in the first intron of FTO have been robustly replicated for associations with obesity. In the Sorbs, a Slavic population resident in Germany, the strongest effect on body mass index (BMI) was found for a variant in the third intron of FTO (rs17818902). Since this may indicate population specific effects of FTO variants, we initiated studies testing FTO for signatures of selection in vertebrate species and human populations., Methods: First, we analyzed the coding region of 35 vertebrate FTO orthologs with Phylogenetic Analysis by Maximum Likelihood (PAML, ω = dN/dS) to screen for signatures of selection among species. Second, we investigated human population (Europeans/CEU, Yoruba/YRI, Chinese/CHB, Japanese/JPT, Sorbs) SNP data for footprints of selection using DnaSP version 4.5 and the Haplotter/PhaseII. Finally, using ConSite we compared transcription factor (TF) binding sites at sequences harbouring FTO SNPs in intron three., Results: PAML analyses revealed strong conservation in coding region of FTO (ω<1). Sliding-window results from population genetic analyses provided highly significant (p<0.001) signatures for balancing selection specifically in the third intron (e.g. Tajima's D in Sorbs = 2.77). We observed several alterations in TF binding sites, e.g. TCF3 binding site introduced by the rs17818902 minor allele., Conclusion: Population genetic analysis revealed signatures of balancing selection at the FTO locus with a prominent signal in intron three, a genomic region with strong association with BMI in the Sorbs. Our data support the hypothesis that genes associated with obesity may have been under evolutionary selective pressure.

Chemerin is an adipokine proposed to link obesity and chronic inflammation of adipose tissue. Genetic factors determining chemerin release from adipose tissue are yet unknown. We conducted a meta-analysis of genome-wide association studies (GWAS) for serum chemerin in three independent cohorts from Europe: Sorbs and KORA from Germany and PPP-Botnia from Finland (total N = 2,791). In addition, we measured mRNA expression of genes within the associated loci in peripheral mononuclear cells by micro-arrays, and within adipose tissue by quantitative RT-PCR and performed mRNA expression quantitative trait and expression-chemerin association studies to functionally substantiate our loci. Heritability estimate of circulating chemerin levels was 16.2% in the Sorbs cohort. Thirty single nucleotide polymorphisms (SNPs) at chromosome 7 within the retinoic acid receptor responder 2 (RARRES2)/Leucine Rich Repeat Containing (LRRC61) locus reached genome-wide significance (p<5.0×10-8) in the meta-analysis (the strongest evidence for association at rs7806429 with p = 7.8×10-14, beta = -0.067, explained variance 2.0%). All other SNPs within the cluster were in linkage disequilibrium with rs7806429 (minimum r2 = 0.43 in the Sorbs cohort). The results of the subgroup analyses of males and females were consistent with the results found in the total cohort. No significant SNP-sex interaction was observed. rs7806429 was associated with mRNA expression of RARRES2 in visceral adipose tissue in women (p<0.05 after adjusting for age and body mass index). In conclusion, the present meta-GWAS combined with mRNA expression studies highlights the role of genetic variation in the RARRES2 locus in the regulation of circulating chemerin concentrations.

Background: The complex process of development of the pituitary gland is regulated by a number of signalling molecules and transcription factors. Mutations in these factors have been identified in rare cases of congenital hypopituitarism but for most subjects with combined pituitary hormone deficiency (CPHD) genetic causes are unknown. Bone morphogenetic proteins (BMPs) affect induction and growth of the pituitary primordium and thus represent plausible candidates for mutational screening of patients with CPHD., Methods: We sequenced BMP2, 4 and 7 in 19 subjects with CPHD. For validation purposes, novel genetic variants were genotyped in 1046 healthy subjects. Additionally, potential functional relevance for most promising variants has been assessed by phylogenetic analyses and prediction of effects on protein structure., Results: Sequencing revealed two novel variants and confirmed 30 previously known polymorphisms and mutations in BMP2, 4 and 7. Although phylogenetic analyses indicated that these variants map within strongly conserved gene regions, there was no direct support for their impact on protein structure when applying predictive bioinformatics tools., Conclusions: A mutation in the BMP4 coding region resulting in an amino acid exchange (p.Arg300Pro) appeared most interesting among the identified variants. Further functional analyses are required to ultimately map the relevance of these novel variants in CPHD.

Unlabelled: A recent genome-wide association study suggests that genetic variation within the vaspin gene might contribute to the variability in circulating serum visceral adipose tissue-derived serine protease inhibitor (vaspin) concentrations. Here, we analyzed the functional consequences of the rare variant rs61757459 predicting a premature stop codon and its impact on circulating serum vaspin concentrations. In order to identify genetic variation, we sequenced the vaspin gene in 48 nonrelated Caucasian subjects. Rs61757459 was subsequently genotyped in three metabolically well-characterized German cohorts (N = 4,019). We addressed the impact of rs61757459 on the crystal structure of vaspin and investigated its effects on vaspin expression in vivo as well as in vitro using various cell lines (Escherichia coli, HEK293). Along with previously reported common genetic variants, sequencing of vaspin revealed a rare variant (rs61757459; minor allele frequency: 1 %) which predicts a premature stop codon p.R211X. Heterozygous carriers of this mutation had lower circulating vaspin levels when compared with noncarriers. In silico structure analysis of the truncated vaspin, which was estimated to be 24.5 kDa, suggested misfolding and potential instability due to the absence of core structural domains. Indeed, the truncated protein was detected after recombinant expression in E. coli and in lysate, but not in supernatant of HEK293 cells. We conclude that rs61757459 is a functional mutation that results in a truncated protein whose instability likely results in reduced serum vaspin levels., Key Message: A rare variant (rs61757459) in vaspin coding for the stop codon p.R211X is related to lower circulating vaspin concentrations. Structure analysis suggests misfolding and instability due to the absence of core structural domains. The truncated protein is detectable after recombinant expression in E. coli and in lysate, but not in supernatant of HEK293 cells.

Although numerous genes are known to regulate serum lipid traits, identified variants explain only a small proportion of the expected heritability. We intended to identify further genetic variants associated with lipid phenotypes in a self-contained population of Sorbs in Germany. We performed a genome-wide association study (GWAS) on LDL-cholesterol, HDL-cholesterol (HDL-C), and triglyceride (TG) levels in 839 Sorbs. All single-nucleotide polymorphisms with a P value <0.01 were subjected to a meta-analysis, including an independent Swedish cohort (Diabetes Genetics Initiative; n = ∼3,100). Novel association signals with the strongest effects were subjected to replication studies in an additional German cohort (Berlin, n = 2,031). In the initial GWAS in the Sorbs, we identified 14 loci associated with lipid phenotypes reaching P values <10⁻⁵ and confirmed significant effects for 18 previously reported loci. The combined meta-analysis of the three study cohorts (n(HDL) = 6041; n(LDL) = 5,995; n(TG) = 6,087) revealed a novel association for a variant in THOC5 (rs8135828) with serum HDL-C levels (P = 1.78 × 10⁻⁷; Z-score = -5.221). Consistently, the variant was also associated with circulating APOA1 levels in Sorbs. The small interfering RNA-mediated mRNA silencing of THOC5 in HepG2 cells resulted in lower mRNA levels of APOA1, SCARB1, and ABCG8 (all P < 0.05). We propose THOC5 to be a novel gene involved in the regulation of serum HDL-C levels.

Objective: The adipokine vaspin (visceral adipose tissue derived serine protease inhibitor, serpinA12) follows a meal-related diurnal variation in humans and intracerebroventricular vaspin administration leads to acutely reduced food intake in db/db mice. We therefore hypothesized that vaspin may play a role in human eating behaviour., Materials and Methods: We measured serum vaspin concentrations in 548 subjects from a self-contained population of Sorbs (Germany) who underwent detailed metabolic testing including eating behaviour assessments using the three-factor eating questionnaire. In addition, genetic variation within vaspin was assessed by genotyping 28 single nucleotide polymorphisms (SNPs) in all study subjects., Results: Serum vaspin concentrations correlated positively with restraint, disinhibition and hunger (all P<0.05), although the correlations did not withstand further adjustments for age, gender and BMI (all P>0.05). Independent of observed correlations, genetic variants in vaspin were associated with serum vaspin levels but showed no significant association with any of the eating behaviour phenotypes after accounting for multiple testing (P≥0.05 after adjusting for age, gender and BMI)., Conclusion: Our data suggest that serum vaspin concentrations might modulate human eating behaviour, which does not seem to be affected by common genetic variation in vaspin.

Anti-inflammatory, anti-atherogenic and anti-diabetic properties of adiponectin make this adipokine an attractive target in the metabolism research. Given its biological role, genetic variation in adiponectin affecting its function might consequently play a role in the pathophysiology of various metabolic disorders. In this light, genetic aspects of adiponectin including its gene structure, heritability of serum concentrations and the role of genetic variation have been addressed in multiple genetic studies. Here, we provide a brief summary of adiponectin genetics with focus on gene structure and genetic variation controlling circulating adiponectin levels. We summarize the main findings from genome-wide linkage and association studies that have revealed the major genetic determinants of serum adiponectin. Beside genetic variants in the adiponectin gene, several other genes/loci (ARL15, CDH13, KNG1, FER, ETV5) contributing to the variability in circulating adiponectin have been identified. The majority of these variants are significantly associated with metabolic phenotypes relevant to metabolic diseases (e.g. obesity or type 2 diabetes (T2D)). Considering the protective properties of adiponectin in diseases such as T2D, comprehensive analyses of genetic variants including rare as well as frequent polymorphisms might provide insights on the specific role of adiponectin in the pathophysiology of metabolic diseases., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Aims: Mutations in the sodium-glucose cotransporter 2 (SGLT2), as well as treatment with SGLT2 inhibitors result in reduced fasting glucose levels, HbA(1c) and BMI. We therefore investigated the effects of common genetic variation in SGLT2 on human Type 2 diabetes and related traits., Materials & Methods: Four HapMap tagging SNPs covering the common genetic variation in SGLT2 (r² > 0.8 and minor allele frequency > 0.01) were genotyped for subsequent association studies on BMI, Type 2 diabetes and related metabolic traits in 1013 Sorbs (Germany). An independent cohort from Berlin (n = 2042) was taken for replication., Results: The rs9934336 G-allele was nominally associated with increased 30-min plasma glucose, 120-min insulin concentrations and AUC120min(glucose) during oral glucose tolerance test in 907 nondiabetic Sorbs (p < 0.05). In the combined analysis including the Sorbs and the Berlin cohort, rs9934336 was nominally associated with 120-min insulin concentrations (adjusted p < 0.05) in nondiabetic subjects (n = 2590)., Conclusion: Our data suggest a role of SGLT2 genetic variation in the regulation of glucose homeostasis and promote pharmacogenomic studies to clarify the efficacy of antidiabetic treatment by SGLT2 inhibitors.

Objective: Human bone morphogenetic protein receptor 2 (BMPR2) is essential for BMP signalling and may be involved in the regulation of adipogenesis. The BMPR2 locus has been suggested as target of recent selection in human populations. We hypothesized that BMPR2 might have a role in the pathophysiology of obesity., Research Design and Methods: Evolutionary analyses (dN/dS, Fst, iHS) were conducted in vertebrates and human populations. BMPR2 mRNA expression was measured in 190 paired samples of visceral and subcutaneous adipose tissue. The gene was sequenced in 48 DNA samples. Nine representative single nucleotide polymorphisms (SNPs) were genotyped for subsequent association studies on quantitative traits related to obesity in 1830 German Caucasians. An independent cohort of 925 Sorbs was used for replication. Finally, relation of genotypes to mRNA in fat was examined., Results: The evolutionary analyses indicated signatures of selection on the BMPR2 locus. BMPR2 mRNA expression was significantly increased both in visceral and subcutaneous adipose tissue of 37 overweight (BMI>25 and <30 kg/m²) and 80 obese (BMI>30 kg/m²) compared with 44 lean subjects (BMI< 25 kg/m²) (P<0.001). In a case-control study including lean and obese subjects, two intronic SNPs (rs6717924, rs13426118) were associated with obesity (adjusted P<0.05). Combined analyses including the initial cohort and the Sorbs confirmed a consistent effect for rs6717924 (combined P = 0.01) on obesity. Moreover, rs6717924 was associated with higher BMPR2 mRNA expression in visceral adipose tissue., Conclusion: Combined BMPR2 genotype-phenotype-mRNA expression data as well as evolutionary aspects suggest a role of BMPR2 in the pathophysiology of obesity.

Aims: The endocannabinoid system may contribute to the association of visceral fat accumulation with metabolic diseases. Here we investigated the effects of genetic variation in the cannabinoid type 1 receptor gene (CNR1) on its mRNA expression in adipose tissue from visceral and subcutaneous depots and on the development of obesity., Materials & Methods: CNR1 was sequenced in 48 nonrelated German Caucasians to detect genetic variation. Five representative variants including HapMap tagging SNPs (rs12720071, rs806368, rs806370, rs1049353 and rs806369) were genotyped for subsequent association studies in two independent cohorts (total n = 2774) with detailed metabolic testing: subjects from the Leipzig Study (n = 1857) and a self-contained population of Sorbs from Germany (n = 917)., Results: In a case-control study of lean (BMI <25 kg/m(2)) versus obese (BMI >30 kg/m(2)) subjects, rs806368 was found to be nominally associated with obesity in the Sorbian cohort (adjusted p < 0.05), but not in the Leipzig cohort. Also, several SNPs (rs806368, rs806370 and rs12720071) were nominally associated with serum leptin levels (p < 0.05 after adjusting for age, sex and BMI). However, none of these associations remained significant after accounting for multiple testing. Furthermore, none of the SNPs were related to CNR1 mRNA expression in visceral and subcutaneous fat., Conclusion: The data suggest that common genetic variation in the CNR1 gene does not influence mRNA expression in adipose tissue nor does it play a significant role in the pathophysiology of obesity in German and Sorbian populations.