Anke Tonjes

Publications of Anke Tonjes

• Visfatin is a positive regulator of MCP-1 in human adipocytes in vitro and in mice in vivo.

  Authors: Grit Sommer, Susan Kralisch, Nora Kloting, Manja Kamprad, Kathleen Schrock, Jurgen Kratzsch, Anke Tonjes, Ulrike Lossner, Matthias Bluher, Michael Stumvoll, Mathias Fasshauer

  Obesity (Silver Spring, Md.). 08/2010; 18(8):1486-92.

  Visfatin is a proinflammatory and potentially insulin-mimetic adipokine contributing to whole body glucose and lipid metabolism, as well as atherosclerosis. Monocyte chemoattractant protein (MCP)-1Visfatin is a proinflammatory and potentially insulin-mimetic adipokine contributing to whole body glucose and lipid metabolism, as well as atherosclerosis. Monocyte chemoattractant protein (MCP)-1 is an adipocyte-secreted protein which might play a crucial role in metabolic and vascular disease. MCP-1 expression and secretion after visfatin treatment were determined by quantitative real-time reverse transcription-PCR and enzyme-linked immunosorbent assay (ELISA) in fully differentiated human mesenchymal stem cell-derived adipocytes (hMSC-Ads) in vitro. In addition, circulating levels of MCP-1 and visfatin were quantified by ELISA in 60 patients (30 nondiabetic, 30 diabetic) and MCP-1 serum levels in mice were determined after visfatin treatment in vivo. Interestingly, protein secretion and mRNA production of MCP-1 were induced significantly in hMSC-Ads after visfatin stimulation. Visfatin-induced MCP-1 secretion 1.9-fold after 8 h and 2.5-fold after 24 h relative to untreated cells (P < 0.05). MCP-1 mRNA synthesis was significantly stimulated by visfatin with maximal upregulation detectable at 250 ng/ml visfatin and after 4 h of treatment. Signaling studies suggested that p44/42 mitogen-activated protein (MAP) kinase is involved in visfatin-induced MCP-1 mRNA expression in hMSC-Ads. Detectability of visfatin in serum predicted circulating MCP-1 independent of age and gender in humans in vivo. MCP-1 serum levels were significantly increased more than twofold after visfatin treatment in mice in vivo. Taken together, our results demonstrate that visfatin upregulates MCP-1 supporting a possible role of MCP-1 in mediating the proinflammatory effects of visfatin.

• Tissue inhibitor of metalloproteinase-1 predicts adiposity in humans.

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

  European journal of endocrinology / European Federation of Endocrine Societies. 03/2007; 156(2):257-61.

  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-1OBJECTIVE: 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 microg/l), s.c. obese (186 +/- 52 microg/l), and visceral obese (198 +/- 42 microg/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.