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The association between common variants in the FTO gene with weight, adiposity and body mass index (BMI) has now been widely replicated. Although the causal variant has yet to be identified, it most likely maps within a 47 kb region of intron 1 of FTO. We performed a genome-wide association study in the Sorbian population and evaluated the relationships between FTO variants and BMI and fat mass in this isolate of Slavonic origin resident in Germany. In a sample of 948 Sorbs, we could replicate the earlier reported associations of intron 1 SNPs with BMI (eg, P-value0.003, Β0.02 for rs8050136). However, using genome-wide association data, we also detected a second independent signal mapping to a region in intron 2/3 about 40-60 kb away from the originally reported SNPs (eg, for rs17818902 association with BMI P-value0.0006, Β0.03 and with fat mass P-value0.0018, Β0.079). Both signals remain independently associated in the conditioned analyses. In conclusion, we extend the evidence that FTO variants are associated with BMI by putatively identifying a second susceptibility allele independent of that described earlier. Although further statistical analysis of these findings is hampered by the finite size of the Sorbian isolate, these findings should encourage other groups to seek alternative susceptibility variants within FTO (and other established susceptibility loci) using the opportunities afforded by analyses in populations with divergent mutational and/or demographic histories. © 2010 Macmillan Publishers Limited All rights reserved.

Diabet. Med. 28, 1373–1380 (2011) Abstract Aims Several polymorphisms of the melatonin receptor 1B gene (MTNR1B) have been shown to be associated with elevated fasting plasma glucose and impaired early insulin release. The aim of this study was to assess the effects of MTNR1B variants on traits related to the metabolic syndrome in the self-contained population of Sorbs from Germany. As comprehensive studies concerning the conservation of MTNR1B are lacking, we also evaluated natural selection in vertebrates and human populations at this locus. Methods Five single nucleotide polymorphisms representing all blocks of linkage disequilibrium within and surrounding the MTNR1B locus were genotyped in 937 Sorbs for association analyses on metabolic traits related to Type 2 diabetes. The associations were assessed by regression analyses, the conservation between species was investigated with phylogenetic analysis by maximum likelihood (PAML). In addition, various tests of population genetic measures (e.g. fixation index, Tajima’s D) were performed. Results Previously reported association between MTNR1B variants (rs10830963, rs4753426) and oral glucose tolerance test-derived indices of β-cell function (homeostasis model assessment-B, P = 3.7 × 10−6 and P = 0.004, respectively), as well as insulin (fasting insulin: P = 2 × 10−3 and P = 0.02; 30-min insulin: P = 2.1 × 10−4 and P = 0.03, respectively) and fasting glucose (rs10830963, P = 1.2 × 10−6) parameters could be replicated in the present study. Phylogenetic analysis by maximum likelihood analyses showed that the gene was strongly conserved between species (ω = 0.2583). Structures important for the receptor function are also conserved. On the lineage leading to human adaptive selection was present (ω = 1.1030). Population genetic measures further indicated natural selection. Conclusions Our data support the physiologic importance of MTNR1B in the context of glucose homeostasis and suggest evidence of selection at this locus.

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 2) versus obese (BMI >30 kg/m2) 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.

OBJECTIVE Members of the family of bone morphogenetic proteins (BMPs) are important regulators of adipogenesis. We examined the role of the BMP receptor 1A gene (BMPR1A) in the pathophysiology of human obesity. RESEARCH DESIGN AND METHODS We measured BMPR1A mRNA expression in paired samples of visceral and subcutaneous adipose tissue from 297 subjects and sequenced the BMPR1A in 48 nonrelated white subjects. Twenty-one representative variants including HapMap tagging single nucleotide polymorphisms (SNPs) were then genotyped for association studies in German whites (n = 1,907). For replication analyses, we used a population of Sorbs from Germany (n = 900) and German childhood cohorts (n = 1,029 schoolchildren and 270 obese children). RESULTS mRNA expression of the BMPR1A was significantly increased in both visceral and subcutaneous adipose tissue of overweight and obese subjects compared with lean subjects (P < 0.05). In a case-control study, four SNPs (rs7095025, rs11202222, rs10788528, and rs7922846) were nominally associated with obesity (adjusted P < 0.05). For three SNPs (rs7095025, rs11202222, and rs10788528), the association with obesity was confirmed in the independent cohort of Sorbs (adjusted P < 0.005). Consistent with this, BMPR1A SNPs were nominally associated with obesity-related quantitative traits in nondiabetic subjects in both adult cohorts. Furthermore, homozygous carriers of the obesity risk alleles had higher BMPR1A mRNA expression in fat than noncarriers. CONCLUSIONS Our data suggest that genetic variation in the BMPR1A may play a role in the pathophysiology of human obesity, possibly mediated through effects on mRNA expression.

Industrial production of nanosized drug delivery devices is still an obstacle to the commercialization of nanomedicines. This study encompasses the development of nanoparticles for peroral application in photodynamic therapy, optimization according to the selected product specifications, and the translation into a continuous flow process. Polymeric nanoparticles were prepared by nanoprecipitation of Eudragit® RS 100 in presence and in absence of glycofurol. The photosensitizer temoporfin has been encapsulated into these carrier devices. Process parameters were optimized by means of a Design of Experiments approach and nanoparticles with optimal characteristics were manufactured by using microreactor technology. The efficacy was determined by means of cell culture models in A-253 cells. Physicochemical properties of nanoparticles achieved by nanoprecipitation from ethanolic solutions were superior to those obtained from a method based upon glycofurol. Nanoencapsulation of temoporfin into the matrix significantly reduced toxicity of this compound, while the efficacy was maintained. The release profiles assured a sustained release at the site of action. Finally, the transfer to continuous flow technology was achieved. By adjusting all process parameters, a potent formulation for application in the GI tract was obtained. The essential steps of process development and scale-up were part of this formulation development.

Aims: Mutations in the sodium–glucose cotransporter 2 (SGLT2), as well as treatment with SGLT2 inhibitors result in reduced fasting glucose levels, HbA1c 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 AUC120minglucose 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. Original submitted 2 March 2011; Revision submitted 22 April 2011

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) compared with 44 lean subjects (BMI

Inhibition of fatty acid synthase (FASN) induces a rapid decline in fat stores in mice, suggesting a role for this enzyme in energy homeostasis. To investigate the potential role of FASN in the pathophysiology of human obesity, the FASN gene was sequenced in 48 German whites. Thirty-five single-nucleotide polymorphisms (SNPs) were identified. Eight SNPs representative for their linkage disequilibrium groups and the Val1483Ile (rs2228305) substitution were genotyped for subsequent association analyses in 1,311 adults from Germany. Further, the tagging SNPs were genotyped also in German childhood cohorts (738 schoolchildren, 205 obese children). Effects of genetic variation on FASN mRNA expression in visceral and subcutaneous adipose tissue from a subgroup of 172 subjects were analyzed. Several polymorphisms in the FASN (rs62078748, rs2229422, rs2229425, and rs17848939) were nominally associated with obesity in case-control studies including 446 obese subjects (BMIor=30 kg/m(2)) and 389 lean controls (BMIor=25 kg/m(2)) (adjusted P0.05). The strongest significant effect was found for rs2229422 (P = 1.3 x 10(-5) adjusted for age, sex, type 2 diabetes status), which was supported by associations with BMI, waist-to-hip ratio (WHR), fasting plasma insulin and glucose infusion rate (adjusted P0.05). Subjects with the Val1483Ile substitution appeared to be protected against obesity. In addition, rs17848939 was nominally significantly associated with the ratio of visceral/subcutaneous FASN mRNA expression (adjusted P = 0.04). No effect of genetic variation in FASN on obesity was found in children. In conclusion, our data indicate a role of FASN genetic variation in susceptibility to obesity in adults.

Recently, associations of several common genetic variants with height have been reported in different populations. We attempted to identify further variants associated with adult height in a self-contained population (the Sorbs in Eastern Germany) as discovery set. We performed a genome wide association study (GWAS) (similar to 390 000 genetic polymorphisms, Affymetrix gene arrays) on adult height in 929 Sorbian individuals. Subsequently, the best SNPs (P < 0.001) were taken forward to a meta-analysis together with two independent cohorts [Diabetes Genetics Initiative, British 1958 Birth Cohort, (58BC, publicly available)]. Furthermore, we genotyped our best signal for replication in two additional German cohorts (Leipzig, n = 1044 and Berlin, n = 1728). In the primary Sorbian GWAS, we identified 5 loci with a P-value < 10(-5) and 455 SNPs with P-value < 0.001. In the meta-analysis on those 455 SNPs, only two variants in GPR133 (rs1569019 and rs1976930; in LD with each other) retained a P-value at or below 10(-6) and were associated with height in the three cohorts individually. Upon replication, the SNP rs1569019 showed significant effects on height in the Leipzig cohort (P = 0.004, beta = 1.166) and in 577 men of the Berlin cohort (P = 0.049, beta = 1.127) though not in women. The combined analysis of all five cohorts (n = 6,687) resulted in a P-value of 4.7 x 10(-8) (beta = 0.949). In conclusion, our GWAS suggests novel loci influencing height. In view of the robust replication in five different cohorts, we propose GPR133 to be a novel gene associated with adult height. (Less)

Background There has been a lack of systematic in-depth research on the motives of living liver donors before transplantation that could contribute to an advanced understanding of their situation and to a more precise psychosocial evaluation, to protect the autonomy for decision, and to prevent psychosocial complications. Methods Twenty-eight living liver donors were assessed preoperatively through a semistructured clinical interview. The taped and transcribed interviews were analyzed using a combination of grounded theory and empirically grounded type construction. Results Various factors contribute to the donor's motivation for donation: the relationship to the recipient, the personal attitude of the donor, his or her personal history, family dynamics, the donor's personal profit, and the exceptional situation of the recipient's life-threatening disease combined with the life-rescuing possibility of living-donor liver transplantation (LDLT). In reference to this, five "ideal types" of living donors emerged from the authors' data. Conclusions A complete absence of coercion on the decision to donate seems unrealistic because of the dynamics initiated by the life-threatening condition of the recipient. It is important that donors feel they are gaining something by donation to be sufficiently motivated and that their profit is of an emotional or moral nature (i.e., the donation being set in an emotionally meaningful context). A mature relationship with the recipient usually provides such a context. The role of the clinician as a part of LDLT dynamics has a decisive influence.