Plasma myostatin is only a weak predictor for weight maintenance in obese adults.

BACKGROUND: Predicting an individual's success in a non-surgical weight loss approach is a demanding need since obesity is becoming an epidemic burden. A possible predictive marker is myostatin, a member of the transforming growth factor b superfamily, which has been shown to be an important regulator of muscle homeostasis. METHODS: In the present study, we analyzed myostatin as a marker to predict weight loss of patients that participated in a 2 phased weight reduction program, comprising a weight loss period of 12 weeks and a weight stabilization period of 40 weeks. Therefore, 62 obese individuals with a mean BMI of 40.6 kg/m(2) were included. Plasma myostatin was measured with ELISA at the beginning (T0), after weight loss (T1) and at the end of the program (T2). RESULTS: Although significant weight loss of -23.9±14.9 kg was achieved, myostatin did not change significantly during the program (T0>T1: p=0.46; T1>T2: p=0.70; T0>T2: p=0.57). Myostatin at baseline did neither negatively correlate with the achieved weight loss in the weight reduction phase (T0>T1: r=0.27, p=0.16) nor with weight loss during the whole program (T0>T2: r=0.20, p=0.29). Only a minor correlation with myostatin levels after weight loss with weight regain during maintenance period was detected. (T1>T2: r=-0.37, p=0.05). CONCLUSION: Plasma myostatin might be suitable in predicting weight regain after marked weight loss, but no association with weight loss was observed in patients undergoing a non-surgical weight loss program. Therefore, myostatin does not seem to be a predictor for success in non-surgical weight loss approaches.

[Challenges in building a surgical obesity center]. / Herausforderungen beim Aufbau eines operativen Adipositaszentrums.

BACKGROUND: It is estimated that approximately 1 million adults in Germany suffer from grade III obesity. The aim of this article is to describe the challenges faced when constructing an operative obesity center. METHODS: The inflow of patients as well as personnel and infrastructure of the interdisciplinary Diabetes and Obesity Center in Heidelberg were analyzed. The distribution of continuous data was described by mean values and standard deviation and analyzed using variance analysis. RESULTS: The interdisciplinary Diabetes and Obesity Center in Heidelberg was founded in 2006 and offers conservative therapeutic treatment and all currently available operative procedures. For every operative intervention carried out an average of 1.7 expert reports and 0.3 counter expertises were necessary. The time period from the initial presentation of patients in the department of surgery to an operation was on average 12.8 months (standard deviation SD ± 4.5 months). The 47 patients for whom remuneration for treatment was initially refused had an average body mass index (BMI) of 49.2 kg/m(2) and of these 39 had at least the necessity for treatment of a comorbidity. Of the 45 patients for whom the reason for the refusal of treatment costs was given as a lack of conservative treatment, 30 had undertaken a medically supervised attempt at losing weight over at least 6 months. Additionally, 19 of these patients could document participation in a course at a rehabilitation center, a Xenical® or Reduktil® therapy or had undertaken the Optifast® program. For the 20 patients who supposedly lacked a psychosomatic evaluation, an adequate psychosomatic evaluation was carried out in all cases. CONCLUSIONS: The establishment of an operative obesity center can last for several years. A essential prerequisite for success seems to be the constructive and targeted cooperation with the health insurance companies.

C332C genotype of glyoxalase 1 and its association with late diabetic complications.

AIMS/INTRODUCTION: Glyoxalase 1 catalyses the detoxification of methylglyoxal, a major precursor of advanced glycation end products associated with aging, neurodegenerative diseases, and microvascular complications of diabetes. Here, we examine a possible association of a single nucleotide polymorphism of glyoxalase 1 gene (Glo1 A332C, rs4746 or rs2736654) with the prevalence of microvascular diabetic complications in patients with type 1 and type 2 diabetes. MATERIALS AND METHODS: Genotyping was performed in 209 patients with type 1 and 524 patients with type 2 diabetes using polymerase chain reaction and subsequent cleavage by restriction endonuclease Bsa I. RESULTS: Frequencies of the glyoxalase 1 genotypes were different with respect to diabetes type with a significantly higher prevalence of A332A-genotype in type 1 diabetes (35.9% vs. 27.3%; p=0.03). In type 1 diabetes, there was no correlation of any genotype with diabetic retinopathy, nephropathy or neuropathy. In contrast, type 2 diabetic patients homozygous for the C332C allele showed a significantly increased prevalence of diabetic neuropathy (p=0.03; OR=1.49 [95%-CI: 1.04; 2.11]), while no association with diabetic nephropathy or retinopathy was found. However, the significance of this association was lost after correction for multiple testing. CONCLUSIONS: Our data suggest a possible association of C332C-genotype of the glyoxalase 1 gene with diabetic neuropathy in type 2 diabetes, supporting the hypothesis that methylglyoxal might be an important mediator of diabetic neuropathy in type 2 diabetes.

[SGLT2 inhibition: an effective therapeutic approach in the treatment of diabetes mellitus?]. / SGLT2-Inhibition: Ein wirksames Therapieprinzip des Diabetes mellitus?

Since end of 2012 a new therapeutical approach for the treatment of type 2 diabetes is available in Germany. It relies on the modulation of glucose re-absorption in the kidney by inhibition of so called Sodium Glucose Linked Transporters (SGLT) thereby leading to therapeutical glucosuria. Putting the kidney in the centre of therapeutical approach of glucose regulation is unfamiliar for physicians. Therefore, it is helpful to elucidate the underlying renal mechanisms and to present the advantages and disadvantages of this new therapeutic class.

[Fundus screening by medical technicians]. / Fundusscreening durch Assistenzpersonal.

Ocular fundus photography allows detection of both ocular and systemic diseases. This study investigated the efficacy of a broad screening in a department of internal medicine using nonmydriatic digital fundus photography. For 8 weeks a medical technician was trained in using the camera as well as interpreting the photographs. The medical technician and an ophthalmologist evaluated the fundus photographs separately by using a self-developed questionnaire. The fundus camera was user-friendly and after several weeks of adjustment and practical application the medical technician was able to detect the majority of pathological fundus photographs. Out of 218 patients examined 148 (68%) were identified as pathological by the medical technician and 163 (75%) by the ophthalmologist (p = 0.0003). The medical technician missed 15 (7%) patients. Furthermore the diagnoses made by the medical technician were faulty. In summary an ophthalmological screening by a medical technician is feasible but the diagnosis still remains the responsibility of ophthalmologists. Such a compromise could facilitate the examination of a large number of patients and disclose previously unrecognized diseases.

The A-allele of the common FTO gene variant rs9939609 complicates weight maintenance in severe obese patients.

OBJECTIVE: The A-allele of the fat mass and obesity-associated (FTO) gene variant rs9939609 has been associated with increased body weight, whereas no effect on weight loss during weight reduction programs has been observed. We questioned whether the AA-genotype interferes with weight stabilization after weight loss. DESIGN: We conducted a monocentric, longitudinal study involving obese individuals. The FTO gene variant rs9939609 was genotyped in participants attending a weight reduction program that was divided into two phases: a weight reduction period with formula diet (12 weeks) and a weight maintenance phase (40 weeks). Body weight, body mass index (BMI), blood pressure and concentrations of blood glucose, total cholesterol, low-density lipoprotein, high-density lipoprotein and triglycerides were determined in week 0 (T(0)), after 12 weeks (T(1)) and at the end in week 52 (T(2)). SUBJECTS: A total of 193 obese subjects aged between 18 and 72 years (129 female, 64 male; initial body weight: 122.4±22.3 kg, initial BMI: 41.8±6.7 kg m(-2)) were included. RESULTS: Genotyping revealed 32.1% TT-, 39.4% AT- and 28.5% AA-genotype carriers. At T (0), carriers of the AA-genotype had significantly higher body weight (P=0.04) and BMI (P=0.005) than carriers of the TT-genotype. Of the 193 participants, 68 discontinued and 125 completed the program. Dropout rate was not influenced by genotype (P=0.33). Completers with AA-genotype showed significantly lower additional weight loss during the weight maintenance phase than TT-genotype carriers (P=0.02). Furthermore, among participants facing weight regain during weight maintenance (n=52), more subjects were carrying the AA-genotype (P=0.006). No influence of genotype on weight reduction under formula diet was observed (P=0.32). CONCLUSION: In this program, the AA-genotype of rs9939609 was associated with a higher initial body weight and did influence success of weight stabilization. Thus, emphasizing the maintenance phase during a weight reduction program might result in better success for AA-genotype carriers.

Weight loss improves endothelial function independently of ADMA reduction in severe obesity.

This prospective study was performed in order to establish whether improvement of endothelial function after weight reduction can be explained by a decrease of elevated asymmetric dimethyl arginine (ADMA), an inhibitor of endogenous NO-synthase (eNOS). Therefore, 21 obese subjects (BMI: 41.1±6.4 kg/m(2)) were studied at baseline and after 12 weeks of weight reduction with a very low calorie diet. Biochemical and clinical parameters of endothelial function were assessed before and after weight loss. Biochemical parameters were determined by measurement of ADMA and soluble intercellular adhesion molecule (sICAM). Clinical parameters were assessed by pulse wave analysis (PWA). Weight intervention resulted in a 21.4±6.8 kg reduction of body weight from 119.7±12.8 kg at study start to 98.3±11.6 kg at study end (p<0.001). Accordingly, biochemical markers improved under weight reduction (ADMA from 0.47±0.07 mmol/l to 0.42±0.08 mmol/l; p=0.002; ICAM from 276±42 ng/ml to 236±29 ng/ml; p<0.001). Further, clinical parameters of functional endothelial function improved with an increase of deltaRI after salbutamol inhalation from -1% before to -9% after weight reduction (p=0.02). Interestingly, improvement of endothelial function correlated with improved HOMA index only (r=-0.60, p=0.04) but not with reduced ADMA levels, improved hypertension or reduced body weight. In conclusion, weight reduction with a very low calorie diet improves endothelial function measured by pulse wave velocity. The missing correlation with ADMA suggests possible further mechanisms underlying this observed effect, for example, improvement of insulin resistance.

Tissue inhibitor of matrix metalloproteinase 1 (TIMP1) controls adipogenesis in obesity in mice and in humans.

AIMS/HYPOTHESIS: Extracellular matrix reorganisation is a crucial step of adipocyte differentiation and is controlled by the matrix metalloproteinase-tissue inhibitor of matrix metalloproteinase (TIMP) enzyme system. We therefore sought to define the role of TIMP1 in adipogenesis and to elucidate whether upregulation of TIMP1 in obesity has direct effects on adipocyte formation. METHODS: TIMP1 protein levels and mRNA were measured in lean and obese mice with a focus on levels in adipose tissue. We also analysed the effect of recombinant murine TIMP1 on adipogenesis, adipocyte size and metabolic control in vitro and in vivo. RESULTS: TIMP1 levels were increased in the serum and adipose tissue of obese mouse models. Recombinant murine TIMP1 inhibited adipocyte differentiation in 3T3-L1 as well as in subcutaneous primary pre-adipocytes. Conversely, neutralising TIMP1 with a specific antibody enhanced adipocyte differentiation. In vivo, injection of recombinant TIMP1 in mice challenged with a high-fat diet led to enlarged adipocytes. TIMP1-treated mice developed an impaired metabolic profile with increased circulating NEFA levels, hepatic triacylglycerol accumulation and accelerated insulin resistance. Altered glucose clearance in TIMP1-injected mice was due to changes in adipose tissue glucose uptake, whereas muscle glucose clearance remained unaffected. CONCLUSIONS/INTERPRETATION: TIMP1 is a negative regulator of adipogenesis. In vivo, TIMP1 leads to enlarged adipocytes in the state of overnutrition. This might contribute to the detrimental metabolic consequences seen in TIMP1-injected mice, such as systemic fatty acid overload, hepatic lipid accumulation and insulin resistance.

Have we understood diabetes? New tasks for diagnosis and therapy.

Recently published data examining the role of the metabolic syndrome and obesity in cardiovascular disease rendered surprising results. In addition, other studies revealed that there is more to diabetes therapy than lowering blood glucose, which might under certain circumstances even harm patients. In the light that we now know that "death" is as important an endpoint in diabetes as in other diseases, new tools--better than the oral glucose tolerance test--are required to identify the patients at risk, as are additional standards in individualized therapy. A critical view on old concepts is necessary.

The -174G>C IL-6 gene promoter polymorphism and diabetic microvascular complications.

This study examined a possible association of the G>C polymorphism at nucleotide -174 in the promoter region of the interleukin-6 (IL-6) gene (rs1800795) with the prevalence of diabetic complications in 235 patients with type 1 and 498 patients with type 2 diabetes. Genotyping was performed using polymerase chain reaction (PCR) and subsequent cleavage by Nla III restriction endonuclease. Analyzing all diabetic patients together demonstrated that 301 patients (41.1%) carried the GG genotype, 114 (15.6%) the CC genotype, and 318 (43.3%) were heterozygous for the GC genotype. However, there was no correlation of any of the genotypes with the prevalence of diabetic nephropathy or diabetic neuropathy, but subjects with the CC genotype had a significantly higher prevalence of diabetic retinopathy compared to patients with the GC and GG genotype (p=0.016). This association was mainly lost when a logistic regression model was adjusted for diabetes duration (p=0.07). Consistently, a weak but not significant association of the polymorphism with diabetic retinopathy was observed when type 1 and type 2 diabetic patients were analyzed separately (patients with type 1 diabetes: p=0.12; patients with type 2 diabetes: p=0.09). Analogically, no association of the polymorphism was found for diabetic nephropathy or diabetic neuropathy in these groups. In conclusion these data suggest no major influence of the -174G>C variant in the promoter region of the IL-6 gene on the development of microvascular complications in patients with diabetes.

Rosiglitazone reduces angiotensin II and advanced glycation end product-dependent sustained nuclear factor-kappaB activation in cultured human proximal tubular epithelial cells.

Tubular damage is a major feature in the development of diabetic nephropathy. This study investigates the effects of the thiazolidindione rosiglitazone on angiotensin II and advanced glycation end product-induced tubular activation in human proximal tubular epithelial cells IN VITRO. Angiotensin II and advanced glycation end products, both induced a dose-dependent sustained activation of the redox-sensitive transcription factor, Nuclear Factor KAPPA B (NF-kappaB). Nuclear translocation of NF-kappaB was evident already after one hour and persistent for more than four days. Co-incubation of proximal tubular epithelial cells with rosiglitazone significantly reduced angiotensin II and advanced glycation end product-mediated generation of reactive oxygen species, angiotensin II-dependent advanced glycation end product formation, NF-kappaB activation, and NF-kappaB-dependent pro inflammatory gene expression. Most importantly, rosiglitazone effects on NFkappaB activation were maximal at later time points, indicating that rosiglitazone treatment confers long lasting renoprotective effects.

A M55V polymorphism in the SUMO4 gene is associated with a reduced prevalence of diabetic retinopathy in patients with Type 1 diabetes.

AIMS: We studied the association between a functionally relevant M55V polymorphism in the SUMO4 gene with microvascular diabetic complications in patients with type 1 diabetes. METHODS: 223 patients with type 1 diabetes were studied using polymerase chain reaction and subsequent cleavage by restriction endonucleases for the M55V SUMO4 gene variant. RESULTS: No effect of the polymorphism on diabetic neuropathy or diabetic nephropathy was found, but heterozygous or homozygous patients for the M55V polymorphism in the SUMO4 gene had a markedly reduced prevalence of diabetic retinopathy (odds ratio 0.37, 95%-confidence interval (CI) [0.32;0.43]; p=0.004). Furthermore, a multiple logistic regression model showed an age and diabetes duration independent effect of the M55V polymorphisms on the prevalence of diabetic retinopathy (p=0.03), but not of diabetic neuropathy or nephropathy. CONCLUSIONS: Our data indicate that the M55V polymorphism in the SUMO4 gene is associated with a reduced risk of diabetic retinopathy in type 1 diabetes. Thus, the results of our study suggest that posttranslational modification of proteins via SUMO4 could contribute to the development of certain diabetic complications.

The DG10S478 variant in the TCF7L2 gene is not associated with microvascular complications in type 2 diabetes.

OBJECTIVE: The DG10S478 variant in the transcription factor 7-like 2 (TCF7L2) gene is a tetranucleotide repeat with six alleles. Alleles 0, 8 and 12 were found to account for 98% of chromosomes in population based controls. The composite allele X (non zero) has been associated with type 2 diabetes while allele 0 (no insertion) was described as protective. However, no data exist about the influence of DG10S478 variants on manifestation of diabetes and development of diabetic complications. METHODS: 250 patients with type 2 diabetes were tested for the DG10S478 allele X and its association with diabetic complications, age at diagnosis of diabetes and BMI. RESULTS: Allele 0 was found in 42.4% of the examined patients, 45.2% of the participants were found to be heterozygous and 12.4% homozygous for the composite allele X. The correlation of allele X with the age at diagnosis of diabetes was not significant. There was also no association of allele X with retinopathy, nephropathy or neuropathy. Only the correlation with BMI was statistically significant. CONCLUSIONS: The DG10S478 variant seems to have no influence on manifestation of diabetes and the development of microvascular complications.

Improved vascular function upon pioglitazone treatment in type 2 diabetes is not associated with changes in mononuclear NF-kappaB binding activity.

Thiazolidinediones such as pioglitazone have been shown to exert anti-inflammatory effects independent of their insulin sensitizing effects by reducing activation of the proinflammatory transcription factor NF-kappaB in animal models of experimental diabetes. Furthermore, short-term pioglitazone treatment ameliorates endothelial dysfunction in conduit arteries of patients with type 2 diabetes. Since inflammation is supposed to impair flow-mediated vasodilatation, we studied the effects of an 8-week pioglitazone intervention on endothelial function and mononuclear NF-kappaB activation in patients with type 2 diabetes. Twenty patients were included in a randomized, double-blind, placebo-controlled study receiving 30 mg pioglitazone or placebo, respectively. Flow-mediated endothelium dependent vasodilatation (FMD) of the brachial artery, NF-kappaB binding activity in peripheral blood mononuclear cells [pBMC, determined by electrophoretic mobility shift assay (EMSA)] and interleukin-6 (IL-6)-transcription rates (determined by real-time PCR) were measured at study entry and after eight weeks of intervention. Pioglitazone treatment resulted in a significant improvement of FMD (4.3%+/-3.3; p=0.003), while no effect was seen under placebo medication (2.0%+/-2.7; p=0.71). The correction of FMD was neither paralleled by a pioglitazone-dependent reduction in mononuclear NF-kappaB binding activity (DeltaNF-kappaB activity: pioglitazone: 9.2%+/-6.7, p=0.24; placebo: 5.7%+/-19.6; p=0.82) nor in NF-kappaB dependent gene transcription as determined for IL-6 (DeltaIL-6 pioglitazone: +1.8%+/-12.0, p=0.93; placebo: -0.2%+/-9.7; p=0.92). These data demonstrate for the first time that pioglitazone treatment improves endothelial dysfunction in patients with type 2 diabetes without affecting NF-kappaB binding activity and NF-kappaB dependent proinflammatory gene expression in pBMC.

Levels of three distinct p75 neurotrophin receptor forms found in human plasma are altered in type 2 diabetic patients.

AIMS/HYPOTHESIS: The p75 neurotrophin receptor (p75NTR) has been shown to appear in the plasma of diabetic rats, possibly indicating diabetic neuropathy. The aim of this study was to use a semi-quantitative assay for human plasma p75NTR to investigate whether this receptor is a marker of peripheral diabetic neuropathy (DPN) and autonomic cardiovascular neuropathy (CAN) in type 2 diabetic patients. SUBJECTS AND METHODS: Eighty type 2 diabetic patients and 25 controls without diabetes were analysed for p75NTR immunoreactivity by western blot analysis. DPN was assessed using the Neuropathy Disability Score (NDS). Cardiovascular autonomic function was detected using a standardised analysis of heart rate variability. RESULTS: Three distinct p75NTR signals were detectable in human plasma at approximately 75, approximately 51 and approximately 24 kDa, representing the full length receptor (FL) and its intracellular domain (ICD) and extracellular domain (ECD), respectively. Levels of total plasma p75NTR immunoreactivity in patients with type 2 diabetes were similar to those in controls. Type 2 diabetic patients had significantly higher plasma levels of ICD and lower levels of ECD. However, there were no correlations of total p75NTR immunoreactivity or ECD or ICD immunoreactivity with NDS or aspects of CAN. CONCLUSIONS/INTERPRETATION: Levels of the ECD of p75NTR are reduced and levels of the ICD are increased in the plasma of type 2 diabetic patients. None of the p75NTR subunits identified in human plasma seem to be a marker of peripheral or autonomic neuronal function in patients with type 2 diabetes.

Postprandial mononuclear NF-kappaB activation is independent of the AGE-content of a single meal.

OBJECTIVE: Dietary uptake of Advanced Glycation Endproducts (AGE) is supposed to potentially contribute to inflammatory reactions linked to vascular dysfunction and late diabetic complications. One mechanism by which dietary AGE might exert these effects is by activation of the proinflammatory transcription factor NF-kappa-B. The aim of this study was to analyze the postprandial effects of a casein meal with low or high AGE content on postprandial NF-kappaB activation in peripheral blood mononuclear cells (pBMC) of healthy volunteers. RESEARCH DESIGN AND METHODS: Casein was heated for 40 h at 50 degrees C in the presence of sorbitol or glucose, resulting in either minimal (Sorbitol [S]-casein) or large (glucose [G]-casein) amounts of AGE-modified casein. Nine healthy volunteers ate 250 g of both types of casein, whereas both meals were separated at least by 2 weeks. Plasma and pBMC were taken before and 2 h after each meal. Thereafter, the defined AGE carboxymethyllysine (CML) was determined by ELISA and Western blot. NF-kappaB activation in pBMC was assayed using Electrophoretic Mobility Shift Assays (EMSA) and Western blot analysis. RESULTS: S-casein contained only minor amounts of CML and no pentosidine, while G-casein contained large amounts of both. 2 h after ingestion, the S-casein or the G-casein-meal, both, resulted in a non-significant increase in plasma CML and in the intracellular CML-content of pBMC. This was paralleled by a highly significant increase in postprandial mononuclear NF-kappaB-binding activity. Remarkably, neither the extent of NF-kappaB induction (178% for S-casein, 188% for G-casein), nor composition of the NF-kappaB heterodimer (mainly consisting of NF-kappaB p50/p65) were significantly different after intake of S-casein or G-casein. Consistently, Western blots confirmed an increased NF-kappaBp65 nuclear translocation and a decrease of NF-kappaBp65 in the cytoplasm, while no difference in postprandial NF-kappaB nuclear translocation was observed following intake of S-casein or G-casein. CONCLUSION: Postprandial mononuclear NF-kappaB activation after a single meal is independent of the AGE-content of the ingested protein.