@article{JohnGruneOttetal.2018,
  author    = {John, Cathleen and Grune, Jana and Ott, Christiane and Nowotny, Kerstin and Deubel, Stefanie and K{\"u}hne, Arne and Schubert, Carola and Kintscher, Ulrich and Regitz-Zagrosek, Vera and Grune, Tilman},
  title     = {Sex Differences in Cardiac Mitochondria in the New Zealand Obese Mouse},
  series = {Frontiers in Endocrinology},
  volume    = {9},
  journal   = {Frontiers in Endocrinology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-2392},
  doi       = {10.3389/fendo.2018.00732},
  pages     = {9},
  year      = {2018},
  abstract  = {Background: Obesity is a risk factor for diseases including type 2 diabetes mellitus (T2DM) and cardiovascular disorders. Diabetes itself contributes to cardiac damage. Thus, studying cardiovascular events and establishing therapeutic intervention in the period of type T2DM onset and manifestation are of highest importance. Mitochondrial dysfunction is one of the pathophysiological mechanisms leading to impaired cardiac function. Methods: An adequate animal model for studying pathophysiology of T2DM is the New Zealand Obese (NZO) mouse. These mice were maintained on a high-fat diet (HFD) without carbohydrates for 13 weeks followed by 4 week HFD with carbohydrates. NZO mice developed severe obesity and only male mice developed manifest T2DM. We determined cardiac phenotypes and mitochondrial function as well as cardiomyocyte signaling in this model. Results: The development of an obese phenotype and T2DM in male mice was accompanied by an impaired systolic function as judged by echocardiography and MyH6/7 expression. Moreover, the mitochondrial function only in male NZO hearts was significantly reduced and ERK1/2 and AMPK protein levels were altered. Conclusions: This is the first report demonstrating that the cardiac phenotype in male diabetic NZO mice is associated with impaired cardiac energy function and signaling events.},
  language  = {en}
}
@article{CastanoMartinezSchumacherSchumacheretal.2019,
  author    = {Casta{\~n}o Mart{\´i}nez, Mar{\´i}a Teresa and Schumacher, Fabian and Schumacher, Silke and Kochlik, Bastian and Weber, Daniela and Grune, Tilman and Biemann, Ronald and McCann, Adrian and Abraham, Klaus and Weikert, Cornelia and Kleuse, Burkhard and Sch{\"u}rmann, Annette and Laeger, Thomas},
  title     = {Methionine restriction prevents onset of type 2 diabetes in NZO mice},
  series = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  volume    = {33},
  journal   = {The FASEB journal : the official journal of the Federation of American Societies for Experimental Biology},
  number    = {6},
  publisher = {Federation of American Societies for Experimental Biology},
  address   = {Bethesda},
  issn      = {0892-6638},
  doi       = {10.1096/fj.201900150R},
  pages     = {7092 -- 7102},
  year      = {2019},
  abstract  = {Dietary methionine restriction (MR) is well known to reduce body weight by increasing energy expenditure (EE) and insulin sensitivity. An elevated concentration of circulating fibroblast growth factor 21 (FGF21) has been implicated as a potential underlying mechanism. The aims of our study were to test whether dietary MR in the context of a high-fat regimen protects against type 2 diabetes in mice and to investigate whether vegan and vegetarian diets, which have naturally low methionine levels, modulate circulating FGF21 in humans. New Zealand obese (NZO) mice, a model for polygenic obesity and type 2 diabetes, were placed on isocaloric high-fat diets (protein, 16 kcal\%; carbohydrate, 52 kcal\%; fat, 32 kcal\%) that provided methionine at control (Con; 0.86\% methionine) or low levels (0.17\%) for 9 wk. Markers of glucose homeostasis and insulin sensitivity were analyzed. Among humans, low methionine intake and circulating FGF21 levels were investigated by comparing a vegan and a vegetarian diet to an omnivore diet and evaluating the effect of a short-term vegetarian diet on FGF21 induction. In comparison with the Con group, MR led to elevated plasma FGF21 levels and prevented the onset of hyperglycemia in NZO mice. MR-fed mice exhibited increased insulin sensitivity, higher plasma adiponectin levels, increased EE, and up-regulated expression of thermogenic genes in subcutaneous white adipose tissue. Food intake and fat mass did not change. Plasma FGF21 levels were markedly higher in vegan humans compared with omnivores, and circulating FGF21 levels increased significantly in omnivores after 4 d on a vegetarian diet. These data suggest that MR induces FGF21 and protects NZO mice from high-fat diet-induced glucose intolerance and type 2 diabetes. The normoglycemic phenotype in vegans and vegetarians may be caused by induced FGF21. MR akin to vegan and vegetarian diets in humans may offer metabolic benefits via increased circulating levels of FGF21 and merits further investigation.-Castano-Martinez, T., Schumacher, F., Schumacher, S., Kochlik, B., Weber, D., Grune, T., Biemann, R., McCann, A., Abraham, K., Weikert, C., Kleuser, B., Schurmann, A., Laeger, T. Methionine restriction prevents onset of type 2 diabetes in NZO mice.},
  language  = {en}
}