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Susan Kralisch, Matthias Bluher, Anke Tonjes, Ulrike Lossner, Ralf Paschke, Michael Stumvoll and Mathias Fasshauer

Objective: Tissue inhibitor of metalloproteinase (TIMP)-1 is upregulated in fat of obese rodents and promotes adipose tissue development in these animals. However, it is unclear whether TIMP-1 independently predicts adiposity in humans and whether serum levels are increased in s.c. and visceral obesity.

Design: Twenty-four lean, 16 s.c. obese, and 20 visceral obese subjects were studied.

Methods: Plasma TIMP-1 concentrations were quantified using ELISAs and correlated to clinical parameters.

Results: Plasma TIMP-1 levels were significantly different between lean (156 ± 42 μg/l), s.c. obese (186 ± 52 μg/l), and visceral obese (198 ± 42 μg/l) subjects (P < 0.01). Furthermore, TIMP-1 correlated positively with body mass index (BMI), waist-to-hip ratio (WHR), % body fat, fasting insulin, free fatty acids, cholesterol, leptin, interleukin-6, and negatively with adiponectin (P < 0.05). Moreover, TIMP-1 serum levels predicted % body fat but not WHR independent of age, sex, and plasma insulin.

Conclusions: We demonstrate that increased TIMP-1 serum levels are found with increased adiposity in humans.

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Thomas Ebert, Susan Kralisch, Ulrike Wurst, Ulrike Lössner, Jürgen Kratzsch, Matthias Blüher, Michael Stumvoll, Anke Tönjes and Mathias Fasshauer

Objective

Betatrophin has recently been introduced as a novel adipokine/hepatokine, which promotes pancreatic β cell proliferation and improves glucose tolerance in several mouse models of insulin resistance. However, regulation of betatrophin in gestational diabetes mellitus (GDM), as well as its association with markers of obesity, such as glucose and lipid metabolism, inflammation, and renal function, have not been elucidated.

Design and methods

Circulating betatrophin was quantified in 74 women with GDM and 74 healthy and gestational age-matched controls by ELISA. In a subset of the study population comprising of 85 patients (41 previous controls, 44 previous women with GDM), postpartum betatrophin levels were measured in a follow-up study.

Results

Median (interquartile range) serum betatrophin levels were higher in women with GDM (1.79 (0.53) μg/l) as compared to non-diabetic pregnant controls (1.58 (0.44) μg/l) (P=0.002). In multivariate analysis, GDM status was an independent and positive predictor of circulating betatrophin (P=0.001). Furthermore, betatrophin levels were significantly higher during gestation (1.70 (0.53) μg/l) as compared to postpartum levels (1.55 (0.66) μg/l) (P=0.028). Moreover, postpartum irisin remained a positive and independent predictor of postpartum betatrophin concentrations.

Conclusions

Women with GDM have significantly higher betatrophin levels as compared to healthy pregnant controls and GDM status positively predicts circulating betatrophin. Furthermore, postpartum levels are significantly lower as compared to betatrophin concentrations during pregnancy. Moreover, irisin is a significant predictor of postpartum betatrophin levels.

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Andreas Oberbach, Stefanie Lehmann, Katharina Kirsch, Joanna Krist, Melanie Sonnabend, Axel Linke, Anke Tönjes, Michael Stumvoll, Matthias Blüher and Peter Kovacs

Objective

Exercise training has been shown to have anti-inflammatory effects in patients with type 2 diabetes. Changes in interleukin-6 (IL-6) serum concentrations in response to training could contribute to these beneficial effects. However, there are heterogeneous data on whether circulating IL-6 is altered by exercise training. We therefore hypothesize that genetic factors modify the individual changes in IL-6 levels after long-term training.

Research design and methods

The −174G/C variant in the IL-6 gene was genotyped in 60 subjects with impaired glucose tolerance. For a 12-month interventional study, patients were randomized into three groups: a control group (n=16) was compared with one group, which underwent a standardized training program (n=24) and another group, which was treated with 4 mg rosiglitazone once daily (n=20). At baseline, after 1, 6, and 12 months, we measured anthropometric parameters and serum concentration of IL-6 and, at baseline and after 12 months, we determined glucose tolerance and fitness level.

Results

Only in subjects carrying the SNP −174C allele did long-term exercise training result in significantly reduced IL-6 serum concentrations. Multivariate linear regression analysis identified the IL-6 genotype as a significant predictor of changes in IL-6 serum concentrations independent of age, gender and improvement in body mass index, hemoglobin (Hb)A1c, and fitness level in response to training.

Conclusions

Genetic variants in the IL-6 gene significantly modify changes in IL-6 serum concentrations in response to long-term exercise training programs. Our data suggest that genetic factors are important determinants for the individual response to anti-inflammatory effects of exercise training.

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Andreas Oberbach, Anke Tönjes, Nora Klöting, Mathias Fasshauer, Jürgen Kratzsch, Martin W Busse, Ralf Paschke, Michael Stumvoll and Matthias Blüher

Objective: Subclinical chronic inflammation could be a unifying factor linking type 2 diabetes (T2D) and atherosclerosis. The beneficial effects of physical activity on a reduced risk of coronary heart disease could at least in part be mediated by improved markers of inflammation.

Research design and methods: The aim of this study was to determine the effect of 4 weeks of physical training on plasma concentrations of interleukin (IL)-6, C-reactive protein (CRP), adiponectin and IL-10 in 60 individuals with normal glucose tolerance, impaired glucose tolerance (IGT) or T2D.

Results: In patients with IGT and T2D, significant improvement in body fat, fitness level, glucose metabolism and insulin sensitivity after 4 weeks of physical training was associated with significantly improved plasma concentrations of adiponectin and CRP, but not IL-6. Regression analysis demonstrated only for the anti-inflammatory parameters adiponectin and IL-10 a significant relationship with the decrease in fasting plasma glucose, whereas changes in IL-6 and CRP were not significantly related to changes in fasting plasma glucose, body fat, maximal oxygen uptake, or insulin sensitivity. In a multivariate linear regression analysis, only changes in circulating adiponectin, fasting plasma glucose and percentage body fat were determinants of changes in insulin sensitivity.

Conclusions: Physical training was associated with a near normalization of adiponectin and CRP plasma concentrations in subjects with IGT and T2D. Increased insulin sensitivity after training was most strongly related to changes in adiponectin plasma concentrations, in fasting plasma glucose and percentage body fat, whereas changes in IL-6, IL-10 and CRP plasma concentrations did not significantly contribute to improved insulin sensitivity.

Free access

Christof Schöfl, Martin Grussendorf, Jürgen Honegger, Anke Tönjes, Daniel Thyroke-Gronostay, Bernhard Mayr, Jochen Schopohl and the participants of the German Acromegaly Register

Context

Disease control is a prime target in acromegaly treatment. This should be achievable in the vast majority of patients by available treatment options. For unknown reasons, however, a significant number of patients do not achieve disease control.

Objective

To investigate reasons for failure to achieve disease control in long-standing acromegaly.

Design and methods

Survey based on the German Acromegaly Registry database (1755 patients in 57 centres). Questionnaires were sent to 47 centres treating 178 patients with elevated disease markers (IGF1 and GH) at the last documented database visit out of 1528 patients with a diagnosis dated back ≥2 years. Thirty-three centres returned anonymised information for 120 patients (recall rate 67.4%).

Results

Median age of the 120 patients (58 females) was 57 years (range 17–84). Ninety-four patients had at least one operation, 29 had received radiotherapy and 71 had been previously treated medically. Comorbidities were reported in 67 patients. In 61 patients, disease activity had been controlled since the last documented database visit, while 59 patients still had biochemically active disease. Reasons were patients' denial to escalate therapy (23.3%), non-compliance (20.6%), fluctuating insulin-like growth factor 1 (IGF-1) and growth hormone (GH) levels with normal values at previous visits (23.3%) and modifications in pharmacotherapy (15.1%). Therapy resistance (9.6%), drug side effects (4.1%) and economic considerations (4.1%) were rare reasons.

Conclusions

Main reasons for long-standing active acromegaly were patients' lack of motivation to agree to therapeutic recommendations and non-compliance with medical therapy. Development of patient education programmes could improve long-term control and thus prognosis of acromegalic patients.

Free access

Karen Ruschke, Lauren Fishbein, Arne Dietrich, Nora Klöting, Anke Tönjes, Andreas Oberbach, Mathias Fasshauer, Jost Jenkner, Michael R Schön, Michael Stumvoll, Matthias Blüher and Christos S Mantzoros

Objective

Obesity and type 2 diabetes (T2D) are reaching epidemic proportions in Western societies, and they contribute to substantial morbidity and mortality. The peroxisome proliferator-activated receptor γ (PPARγ) and PPARγ coactivator-1α (PGC-1α) system plays an important role in the regulation of efficient energy utilization and oxidative phosphorylation, both of which are decreased in obesity and insulin resistance.

Design and methods

We measured the metabolic parameters and the expression of PPARγ and PGC-1α mRNA using quantitative real-time PCR in omental and subcutaneous (SC) adipose tissues in an observational study of 153 individuals as well as in SC fat and skeletal muscle in an interventional study of 60 subjects (20 each with normal glucose tolerance, impaired glucose tolerance, and T2D) before and after intensive physical training for 4 weeks.

Results

PPARγ and PGC-1α mRNA expression in both fat depots as well as in skeletal muscle is associated with markers of insulin resistance and cardiovascular risk. PGC-1α mRNA expression is significantly higher in SC fat than in omental fat, whereas PPARγ mRNA expression is not significantly different between these fat depots. Skeletal muscle and SC fat PPARγ and PGC-1α mRNA expression increased significantly in response to physical training.

Conclusions

Gene expression of PPARγ and PGC-1α in human adipose tissue is related to markers of insulin resistance and cardiovascular risk. Increased muscle and adipose tissue PPARγ and PGC-1α expression in response to physical training may mediate the beneficial effects of exercise on insulin sensitivity.