The Role of Phosphatidylethanolamine N-Methyltransferase (PEMT) and Its Waist-Hip-Ratio-Associated Locus rs4646404 in Obesity-Related Metabolic Traits and Liver Disease.

In previous genome-wide association studies (GWAS), genetic loci associated with obesity and impaired fat distribution (FD) have been identified. In the present study, we elucidated the role of the PEMT gene, including the waist-hip-ratio-associated single nucleotide polymorphism rs4646404, and its influence on obesity-related metabolic traits. DNA from 2926 metabolically well-characterized subjects was used for genotyping. PEMT expression was analyzed in paired visceral (vis) and subcutaneous (sc) adipose tissue (AT) from a subset of 574 individuals. Additionally, PEMT expression was examined in vis, sc AT and liver tissue in a separate cohort of 64 patients with morbid obesity and liver disease. An in vitro Pemt knockdown was conducted in murine epididymal and inguinal adipocytes. Our findings highlight tissue-specific variations in PEMT mRNA expression across the three studied tissues. Specifically, vis PEMT mRNA levels correlated significantly with T2D and were implicated in the progression of non-alcoholic steatohepatitis (NASH), in contrast to liver tissue, where no significant associations were found. Moreover, sc PEMT expression showed significant correlations with several anthropometric- and metabolic-related parameters. The rs4646404 was associated with vis AT PEMT expression and also with diabetes-related traits. Our in vitro experiments supported the influence of PEMT on adipogenesis, emphasizing its role in AT biology. In summary, our data suggest that PEMT plays a role in regulating FD and has implications in metabolic diseases.

Topical 188Re Ionizing Radiation Therapy Exerts High Efficacy in Curing Nonmelanoma Skin Cancer.

PURPOSE OF THE REPORT: Nonmelanoma skin cancer (NMSC) is the most frequent malignancy. Surgical intervention is the common treatment but may lead to disappointing results; alternative treatment options are needed. METHODS: In this monocentric pilot study, topical 188Re resin was investigated as a treatment for invasive NMSC up to 3-mm thickness. Twenty-two patients with 40 histologically confirmed NMSCs with a median size of 1.25 cm2 (range, 0.04-16.8 cm2) and a median tumor thickness of 0.35 mm (range, 0.1-2.1 mm) were included. Patients were treated once with 188Re resin with a targeted dose of 50 Gy. The median applied activity was 111.4 MBq (range, 21.0-168.0 MBq), and the median treatment time was 89 minutes (range, 38-175 minutes). The response rate, adverse events, and cosmetic outcome were assessed at 14 days, 4 months, and 12 months. RESULTS: Response rate at 12 months was 97.5%, with 95% complete responses (clinically or histologically proven in case of clinical doubt). Most adverse events were reported at 14 days, with 20% itching and 12.5% mostly minor pain. Forty-nine percent of the lesions showed hypopigmentation only at 12 months. Forty-one percent of the lesions were graded as cosmetically superior to the expected result after surgery and 51.3% as comparable to successful surgery. The cosmetic outcome on the head and face was superior compared with the trunk and leg (P = 0.003). CONCLUSION: 188Re resin is a highly effective treatment for NMSC up to 3-mm thickness and a valid alternative to surgery, specifically for tumors located on sensitive areas such as nose or ear.

Sex-Specific Effects of the Genetic Variant rs10487505 Upstream of leptin in the Development of Obesity.

The SNP rs10487505 in the promotor region of the leptin gene was reported to be associated with decreased circulating leptin and increased body mass index (BMI). However, the phenotypic outcomes affected by rs10487505 in the leptin regulatory pathway have not been systematically studied. Therefore, the aim of this study was to elucidate the influence of rs10487505 on leptin mRNA expression and obesity-related parameters. We genotyped rs10487505 in DNA samples from 1665 patients with obesity and lean controls and measured leptin gene expression in paired samples of adipose tissue (AT, N = 310), as well as circulating leptin levels. We confirm the leptin-lowering effect of rs10487505 in women. In contrast to the previously reported data from population-based studies, in this mainly obese cohort, we describe a lower mean BMI in women carrying the C allele of rs10487505. However, no association of rs10487505 with AT leptin mRNA expression was found. Our data suggest that reduced circulating leptin levels are not a result of the direct silencing of leptin mRNA expression. Furthermore, leptin reduction by rs10487505 does not associate with BMI in a linear manner. Instead, the decreasing effect on BMI might be dependent on the severity of obesity.

Metabolic Effects of the Waist-To-Hip Ratio Associated Locus GRB14/COBLL1 Are Related to GRB14 Expression in Adipose Tissue.

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.

Pain Management Program in Cardiology: A Template for Application of Normalization Process Theory and Social Marketing to Implement a Change in Practice Quality Improvement.

Quality improvement plays a major role in healthcare, and numerous approaches have been developed to implement changes. However, the reasons for success or failure of the methods applied often remains obscure. Normalization process theory, recently developed in sociology, provides a flexible framework upon which to construct quality improvement. We sought to determine if examination of a successful quality improvement project, using normalization process theory and social marketing, provided insight into implementation. We performed a retrospective analysis of the steps taken to implement a pain management program in an electrophysiology clinic. We mapped these steps, and the corresponding social marketing tools used, to elements of normalization process theory. The combination of mapping implementation steps and marketing approaches to the theory provided insight into the quality-improvement process. Specifically, examination of the steps in the context of normalization process theory highlighted barriers to implementation at individual, group, and organizational levels. Importantly, the mapping also highlighted how facilitators were able to overcome the barriers with marketing techniques. Furthermore, integration with social marketing revealed how promotion of tangibility of benefits aided communication and how process co-creation between stakeholders enhanced value. Our implementation of a pain-management program was successful in a challenging environment composed of several stakeholder groups with entrenched initial positions. Therefore, we propose that the behavior change elements of normalization process theory combined with social marketing provide a flexible framework to initiate quality improvement.

Adipsin Serum Concentrations and Adipose Tissue Expression in People with Obesity and Type 2 Diabetes.

(1) Adipsin is an adipokine that may link increased fat mass and adipose tissue dysfunction to obesity-related cardiometabolic diseases. Here, we investigated whether adipsin serum concentrations and adipose tissue (AT) adipsin mRNA expression are related to parameters of AT function, obesity and type 2 diabetes (T2D). (2) Methods: A cohort of 637 individuals with a wide range of age and body weight (Age: 18-85 years; BMI: 19-70 kg/m2) with (n = 237) or without (n = 400) T2D was analyzed for serum adipsin concentrations by ELISA and visceral (VAT) and subcutaneous (SAT) adipsin mRNA expression by RT-PCR. (3) Results: Adipsin serum concentrations were significantly higher in patients with T2D compared to normoglycemic individuals. We found significant positive univariate relationships of adipsin serum concentrations with age (r = 0.282, p < 0.001), body weight (r = 0.264, p < 0.001), fasting plasma glucose (r = 0.136, p = 0.006) and leptin serum concentrations (r = 0.362, p < 0.001). Neither VAT nor SAT adipsin mRNA expression correlated with adipsin serum concentrations after adjusting for age, sex and BMI. Independent of T2D status, we found significantly higher adipsin expression in SAT compared to VAT (4) Conclusions: Our data suggest that adipsin serum concentrations are strongly related to obesity and age. However, neither circulating adipsin nor adipsin AT expression reflects parameters of impaired glucose or lipid metabolism in patients with obesity with or without T2D.

Effects of Weight Loss on Glutathione Peroxidase 3 Serum Concentrations and Adipose Tissue Expression in Human Obesity.

BACKGROUND/AIMS: Altered expression and circulating levels of glutathione peroxidase 3 (GPX3) have been observed in obesity and type 2 diabetes (T2D) across species. Here, we investigate whether GPX3 serum concentrations and adipose tissue (AT) GPX3 mRNA expression are related to obesity and weight loss. METHODS: GPX3 serum concentration was measured in 630 individuals, including a subgroup (n = 293) for which omental and subcutaneous (SC) GPX3 mRNA expression has been analyzed. GPX3 analyses include three interventions: 6 months after bariatric surgery (n = 80) or combined exercise/hypocaloric diet (n = 20) or two-step bariatric surgery (n = 24) studies. RESULTS: Bariatric surgery-induced weight loss (-25.8 ± 8.4%), but not a moderate weight reduction of -8.8 ± 6.5% was associated with significantly reduced GPX3 serum concentrations. GPX3 mRNA is significantly higher expressed in AT from individuals with normal glucose metabolism compared to T2D patients. SC AT GPX3 expression is significantly higher in lean compared to obese as well as in insulin-sensitive compared insulin-resistant individuals with obesity. Weight loss after bariatric surgery causes a significant increase in SC AT GPX3 expression. AT GPX3 expression significantly correlates with age, BMI, fat distribution, insulin sensitivity (only SC AT), but not with circulating GPX3. CONCLUSION: Our data support the notion that SC AT GPX3 expression is associated with obesity, fat distribution and related to whole body insulin resistance.

DNA methylation of SSPN is linked to adipose tissue distribution and glucose metabolism.

DNA methylation is a crucial epigenetic mechanism in obesity and fat distribution. We explored the Sarcospan ( SSPN) gene locus by using genome-wide data sets comprising methylation and expression data, pyrosequencing analysis in the promoter region, and genetic analysis of an SNP variant rs718314, which was previously reported to associate with waist-to-hip ratio. We found that DNA methylation influences several clinical variables related to fat distribution and glucose metabolism, while SSPN mRNA levels showed directionally opposite effects on these traits. Complete DNA methylation of the SSPN promoter construct suppressed the gene expression of firefly luciferase in MCF7 cells. Moreover, rs718314 was associated with waist and with DNA methylation at CpG sites. Our data strongly support the role of the SSPN locus in body fat composition and glucose homeostasis, and suggest that this is most likely the result of changes in DNA methylation of SSPN in adipose tissue.-Keller, M., Klös, M., Rohde, K., Krüger, J., Kurze, T., Dietrich, A., Schön, M. R., Gärtner, D., Lohmann, T., Dreßler, M., Stumvoll, M., Blüher, M., Kovacs, P., Böttcher, Y. DNA methylation of SSPN is linked to adipose tissue distribution and glucose metabolism.

IRS1 DNA promoter methylation and expression in human adipose tissue are related to fat distribution and metabolic traits.

The SNP variant rs2943650 near IRS1 gene locus was previously associated with decreased body fat and IRS1 gene expression as well as an adverse metabolic profile in humans. Here, we hypothesize that these effects may be mediated by an interplay with epigenetic alterations. We measured IRS1 promoter DNA methylation and mRNA expression in paired human subcutaneous and omental visceral adipose tissue samples (SAT and OVAT) from 146 and 41 individuals, respectively. Genotyping of rs2943650 was performed in all individuals (N = 146). We observed a significantly higher IRS1 promoter DNA methylation in OVAT compared to SAT (N = 146, P = 8.0 × 10-6), while expression levels show the opposite effect direction (N = 41, P = 0.011). OVAT and SAT methylation correlated negatively with IRS1 gene expression in obese subjects (N = 16, P = 0.007 and P = 0.010). The major T-allele is related to increased DNA methylation in OVAT (N = 146, P = 0.019). Finally, DNA methylation and gene expression in OVAT correlated with anthropometric traits (waist- circumference waist-to-hip ratio) and parameters of glucose metabolism in obese individuals. Our data suggest that the association between rs2943650 near the IRS1 gene locus with clinically relevant variables may at least be modulated by changes in DNA methylation that translates into altered IRS1 gene expression.

Genome-wide DNA promoter methylation and transcriptome analysis in human adipose tissue unravels novel candidate genes for obesity.

OBJECTIVE/METHODS: DNA methylation plays an important role in obesity and related metabolic complications. We examined genome-wide DNA promoter methylation along with mRNA profiles in paired samples of human subcutaneous adipose tissue (SAT) and omental visceral adipose tissue (OVAT) from non-obese vs. obese individuals. RESULTS: We identified negatively correlated methylation and expression of several obesity-associated genes in our discovery dataset and in silico replicated ETV6 in two independent cohorts. Further, we identified six adipose tissue depot-specific genes (HAND2, HOXC6, PPARG, SORBS2, CD36, and CLDN1). The effects were further supported in additional independent cohorts. Our top hits might play a role in adipogenesis and differentiation, obesity, lipid metabolism, and adipose tissue expandability. Finally, we show that in vitro methylation of SORBS2 directly represses gene expression. CONCLUSIONS: Taken together, our data show distinct tissue specific epigenetic alterations which associate with obesity.

Hypoxia-inducible factor 3A gene expression and methylation in adipose tissue is related to adipose tissue dysfunction.

Recently, a genome-wide analysis identified DNA methylation of the HIF3A (hypoxia-inducible factor 3A) as strongest correlate of BMI. Here we tested the hypothesis that HIF3A mRNA expression and CpG-sites methylation in adipose tissue (AT) and genetic variants in HIF3A are related to parameters of AT distribution and function. In paired samples of subcutaneous AT (SAT) and visceral AT (VAT) from 603 individuals, we measured HIF3A mRNA expression and analyzed its correlation with obesity and related traits. In subgroups of individuals, we investigated the effects on HIF3A genetic variants on its AT expression (N = 603) and methylation of CpG-sites (N = 87). HIF3A expression was significantly higher in SAT compared to VAT and correlated with obesity and parameters of AT dysfunction (including CRP and leucocytes count). HIF3A methylation at cg22891070 was significantly higher in VAT compared to SAT and correlated with BMI, abdominal SAT and VAT area. Rs8102595 showed a nominal significant association with AT HIF3A methylation levels as well as with obesity and fat distribution. HIF3A expression and methylation in AT are fat depot specific, related to obesity and AT dysfunction. Our data support the hypothesis that HIF pathways may play an important role in the development of AT dysfunction in obesity.

Fat depot-specific expression of HOXC9 and HOXC10 may contribute to adverse fat distribution and related metabolic traits.

OBJECTIVE: Independent previous studies in both rodents and humans suggest a role of developmental genes in the origin of obesity and body fat distribution. Here, the hypothesis that human adipose tissue (AT) expression of the developmental genes homeobox transcription factors C9 (HOXC9) and C10 (HOXC10) is fat depot-specific and related to obesity-related traits was tested. METHODS: In 636 individuals, HOXC9 and HOXC10 mRNA expression was investigated in paired abdominal subcutaneous (SC) and omental AT samples in relation to a wide range of age, BMI, fat distribution, and metabolic parameters and in subfractions of isolated adipocytes and cells of the stromal vascular fraction (SVF). RESULTS: HOXC9 and HOXC10 mRNA expression is significantly higher in SC compared to omental AT. HOXC9 and HOXC10 mRNA expression significantly correlates with body fat mass, even after adjustment for age and gender. In smaller subgroups (depending on the availability of data), fat depot-related significant gender- and BMI-independent associations between HOXC9 and HOXC10 gene expression and parameters of glucose metabolism and AT biology were found (e.g., adipocyte size). CONCLUSIONS: Taken together, these data suggest that HOXC9 and HOXC10 may play an important role in the development of obesity, adverse fat distribution, and subsequent alterations in whole-body metabolism and AT function.

ADCY5 gene expression in adipose tissue is related to obesity in men and mice.

Genome wide association studies revealed an association of the single nucleotide polymorphism rs11708067 within the ADCY5 gene--encoding adenylate cyclase 5--with increased type 2 diabetes (T2D) risk and higher fasting glucose. However, it remains unclear whether the association between ADCY5 variants and glycemic traits may involve adipose tissue (AT) related mechanisms. We therefore tested the hypothesis that ADCY5 mRNA expression in human and mouse AT is related to obesity, fat distribution, T2D in humans and high fat diet (HFD) in mice. We measured ADCY5 mRNA expression in paired samples of visceral and subcutaneous adipose tissue from 244 individuals with a wide range of body weight and parameters of hyperglycemia, which have been genotyped for rs11708067. In addition, AT ADCY5 mRNA was assessed in C57BL/6NTac which underwent a 10 weeks standard chow (n = 6) or high fat diet (HFD, n = 6). In humans, visceral ADCY5 expression is significantly higher in obese compared to lean individuals. ADCY5 expression correlates with BMI, body fat mass, circulating leptin, fat distribution, waist and hip circumference, but not with fasting plasma glucose and HbA1c. Adcy5 expression in mouse AT is significantly higher after a HFD compared to chow (p<0.05). Importantly, rs11708067 is not associated with ADCY5 mRNA expression levels in either fat depot in any of the genetic models tested. Our results suggest that changes in AT ADCY5 expression are related to obesity and fat distribution, but not with impaired glucose metabolism and T2D. However, altered ADCY5 expression in AT does not seem to be the mechanism underlying the association between rs11708067 and increased T2D risk.

Global DNA methylation levels in human adipose tissue are related to fat distribution and glucose homeostasis.

AIMS/HYPOTHESIS: Epigenetic alterations may influence the metabolic pathways involved in human obesity. We hypothesised that global DNA methylation levels in adipose tissue might be associated with obesity and related phenotypes. METHODS: We measured global DNA methylation levels in paired samples of subcutaneous adipose tissue (SAT) and omental visceral adipose tissue (OVAT) from 51 individuals, and in leucocytes from 559 Sorbs, a population from Germany, using LUminometric Methylation Assay (LUMA). To further investigate the underlying mechanisms of the observed associations, we measured global methylation levels in 3T3-L1 adipocytes exposed to glucose, insulin and lipids. RESULTS: Global methylation levels (±SD) were significantly higher in OVAT (74.27% ± 2.2%) compared with SAT (71.97% ± 2.4%; paired t test, p < 1 × 10(-9)). Furthermore, global methylation levels in SAT were positive correlates of measures of fat distribution (waist measurement, WHR) and glucose homeostasis (HbA1c) (all p < 0.015 after accounting for multiple testing and covariates). Global methylation levels in the German Sorb cohort were associated with glucose homeostasis, but this association did not withstand adjustment for covariates. Exposure of 3T3-L1 adipocytes to insulin, palmitate and glucose decreased global methylation levels 1 h after treatment relative to controls. CONCLUSIONS/INTERPRETATION: Our data suggest that the variability in global methylation in adipose tissue might be related to alterations in glucose metabolism.

Adipose tissue depot specific promoter methylation of TMEM18.

UNLABELLED: Epigenetic processes such as dynamic promoter methylation may play a role in obesity, fat distribution and its accompanied metabolic alterations. TMEM18 is a candidate gene for body mass index (BMI) comprising the second largest effect size among all loci identified so far via GWAS. We hypothesized that differential TMEM18 gene expression in visceral (VAT) and subcutaneous adipose tissue (SAT) may be a consequence of depot specific differential methylation at the TMEM18 promoter region. Differential methylation levels may confer fat depot specific correlations with measures of obesity and fat distribution. Here, we measured TMEM18 mRNA expression in VAT and SAT from 500 subjects. A total of 146 Caucasian individuals were investigated for differential methylation levels in VAT vs. SAT at three CpG sites. Subsequently, we tested for potential correlation of methylation levels with anthropometric and metabolic parameters. (1) In 500 individuals, we observed significantly decreased mRNA expression in SAT (paired t-test, P < 0.0001) compared to VAT with strongest effects in obese subjects. (2) We identified significantly higher methylation levels for the entire CpG locus in SAT (paired t-test, P = 0.00015). In 146 individuals, we detected positive correlations between CpG methylation levels in SAT with parameters of obesity and fat distribution (e.g., BMI, r = 0.173; P = 0.036; visceral fat area, r = 0.246; P = 0.004) and with metabolic traits (P ≤ 0.05). However, these correlations did not withstand adjustment for covariates. Our data suggest an adipose tissue depot specific TMEM18 promoter methylation that may mediate inter-depot specific variance in TMEM18 mRNA expression. KEY MESSAGES: Higher mean methylation across the entire CpG locus in SAT compared to VAT. Lower TMEM18 mRNA expression levels in SAT compared to VAT. TMEM18 mRNA expression levels are related to phenotypes of obesity and glucose metabolism.

Nicotinamide nucleotide transhydrogenase mRNA expression is related to human obesity.

OBJECTIVE: A spontaneous deletion in the nicotinamide nucleotide transhydrogenase (Nnt) gene eliminating exons 7-11 in C57BL/6J (B6J) mice is associated with reduced glucose-stimulated insulin secretion in vitro, impaired glucose tolerance, higher epigonadal fat mass, and altered susceptibility to diet induced obesity of male B6J mice was proposed. A potential implication for NNT in human adipose tissue distribution has not been investigated so far. DESIGN AND METHODS: Therefore, NNT mRNA expression in paired human samples of visceral (vis) and subcutaneous (sc) adipose tissue from 221 subjects with a wide range of body mass index (BMI), insulin sensitivity, and glucose tolerance was analyzed. RESULTS: NNT mRNA expression is significantly higher in visceral fat of obese patients and correlates with body weight, BMI, % body fat, visceral and sc fat area, waist and hip circumference, and fasting plasma insulin (FPI). Multivariate linear regression analysis revealed visceral NNT expression as age and gender independent predictor of BMI, waist circumference, visceral fat area, and % body fat, but not FPI and 2 h OGTT glucose. CONCLUSION: In conclusion, a functional relevance of NNT in the development of human obesity and visceral fat distribution was suggested here.

Effects of weight loss and exercise on apelin serum concentrations and adipose tissue expression in human obesity.

OBJECTIVE: Apelin is an adipokine which plays a role in the regulation of glucose homeostasis and may contribute to the link between increased adipose tissue mass and obesity related metabolic diseases. Here we investigate the role of omental and subcutaneous (SC) adipose tissue apelin and its receptor APJ mRNA expression in human obesity and test the hypothesis that changes in circulating apelin are associated with reduced fat mass in three weight loss intervention studies. METHODS: Apelin serum concentration was measured in 740 individuals in a cross-sectional (n = 629) study including a subgroup (n = 161) for which omental and SC apelin mRNA expression has been analyzed and in three interventions: 12 weeks exercise (n = 60), 6 months calorie-restricted diet (n = 19), 12 months after bariatric surgery (n = 32). RESULTS: Apelin mRNA is significantly higher expressed in adipose tissue of patients with type 2 diabetes and correlates with circulating apelin, BMI, body fat, C-reactive protein, and insulin sensitivity. Obesity surgery-induced weight loss causes a significant reduction in omental and SC apelin expression. All interventions led to significantly reduced apelin serum concentrations which significantly correlate with improved insulin sensitivity, independently of changes in BMI. CONCLUSIONS: Reduced apelin expression and serum concentration may contribute to improved insulin sensitivity beyond significant weight loss.

Short-term changes of the urine metabolome after bariatric surgery.

Bariatric surgery leads to a loss of excess weight and to a remission of diabetes in a majority of patients. In an attempt to explain these underlying mechanisms, a broad range of metabolic alterations have been suggested. We aimed to investigate short-term changes in the urinary metabolome after bariatric surgery. Data for 50 patients who underwent bariatric surgery at the Municipal Hospital of Dresden-Neustadt, Germany, were used. Healthy controls were selected from the Study of Health in Pomerania. Non-fasting, spontaneous urine samples were collected, (1)H NMR spectroscopic analysis was performed, and metabolites were quantified (Chenomx NMR suite). Orthogonal projections to latent structures discriminant analysis (OPLS-DA) models were carried out (pre-operative versus controls, and post-operative versus controls). On the basis of the urine metabolome separations between pre-operative (predictive ability Q2Y=85.6%; total explained variance R2X=58.3%), or post-operative (Q2Y=82.1%; R2X=44.4%) and controls were possible. Metabolites including hippuric acid, 3-hydroxybutyrate, 2-hydroxyisobutyrate, and trigonelline, were altered among patients. In obese patients, 2-hydroxyisobutyrate levels were higher, whereas trigonelline and hippuric acid levels were lower than in controls. The highest levels of 3-hydroxybutyrate were found in post-operative samples, whereas the metabolite was not present in controls, and only at low levels in pre-operative samples. In conclusion, we demonstrated that the urinary metabotype differs between obese patients and healthy controls. The metabolic alterations identified after bariatric procedures increase our knowledge about the metabolic traits associated with weight reduction. Whether urinary metabotypes might be used for early prediction of a successful bariatric procedure should be evaluated in long-term observations.

Effects of weight loss and exercise on chemerin serum concentrations and adipose tissue expression in human obesity.

Chemerin is a chemoattractant adipokine that regulates adipogenesis and may induce insulin resistance. Chemerin serum concentrations are elevated in obese, insulin-resistant, and inflammatory states in vivo. Here we investigate the role of omental (OM) and subcutaneous (SC) adipose tissue chemerin and CMKLR1 messenger RNA (mRNA) expression in human obesity. In addition, we test the hypothesis that changes in chemerin serum concentrations are primarily associated with reduced body fat mass in the context of 3 weight loss intervention studies. Chemerin serum concentration was measured in 740 individuals in a cross-sectional (n = 629) study including a subgroup (n = 161) for which OM and SC chemerin mRNA expression has been analyzed as well as in 3 interventions including 12 weeks of exercise (n = 60), 6 months of calorie-restricted diet (n = 19) studies, and 12 months after bariatric surgery (n = 32). Chemerin mRNA is significantly higher expressed in adipose tissue of patients with type 2 diabetes mellitus and correlates with circulating chemerin, body mass index (BMI), percentage body fat, C-reactive protein, homeostasis model assessment of insulin resistance, and glucose infusion rate in euglycemic-hyperinsulinemic clamps. CMKLR1 mRNA expression was not significantly different between the 2 fat depots. Obesity surgery-induced weight loss causes a significant reduction on both OM and SC chemerin expression. All interventions led to significantly reduced chemerin serum concentrations. Decreased chemerin serum concentrations significantly correlate with improved glucose infusion rate and reduced C-reactive protein levels independently of changes in BMI. Insulin resistance and inflammation are BMI-independent predictors of elevated chemerin serum concentrations. Reduced chemerin expression and serum concentration may contribute to improved insulin sensitivity and subclinical inflammation beyond significant weight loss.

Genetic and evolutionary analyses of the human bone morphogenetic protein receptor 2 (BMPR2) in the pathophysiology of obesity.

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.