Senda Bahri1,2, Michael Horowitz3, Charles-Henri Malbert1. 1. Aniscan Unit, Department of Human Nutrition, Institut National de la Recherche Agronomique, Saint-Gilles, France. 2. Research Unit UR/11ES09, University of Tunis El Manar, Tunis, Tunisia. 3. Discipline of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, South Australia, Australia.
Abstract
OBJECTIVE: There is a general agreement that there are changes in brain metabolism in insulin-resistant individuals during conditions of hyperinsulinemia. However, the impact on obesity is unclear, and the metabolic constants underlying these modifications are unknown. The aim of this study was to evaluate these changes in a large animal model of diet-induced obesity. METHODS: Twenty adult miniature pigs were fed with either an obesogenic diet or a regular diet for 5 months. At that time, fat deposition was evaluated using computed tomography scanning, and 18 fluorodeoxyglucose positron emission tomography images were acquired dynamically both in the fasted state and during a euglycemic-hyperinsulinemic clamp. Glucose uptake rates and pixel-wise modeled brain volumes were calculated together with brain connectivity. RESULTS: Whole-body insulin sensitivity was reduced by more than 50% in the obesity group. During insulin stimulation, whole-brain insulin-induced increased glucose uptake was unaltered in lean animals but increased markedly in the animals with obesity. The increased glucose uptake reflected an increase in the inward transfer without changes in phosphorylation or outward brain transport. Connectivity was increased in the animals with obesity CONCLUSIONS: Diet-induced obesity is associated with an increase in insulin-stimulated brain glucose uptake as a consequence of a larger inward transfer. These changes occurred together with an increased connectivity in reference to regions associated with memory recollection.
OBJECTIVE: There is a general agreement that there are changes in brain metabolism in insulin-resistant individuals during conditions of hyperinsulinemia. However, the impact on obesity is unclear, and the metabolic constants underlying these modifications are unknown. The aim of this study was to evaluate these changes in a large animal model of diet-induced obesity. METHODS: Twenty adult miniature pigs were fed with either an obesogenic diet or a regular diet for 5 months. At that time, fat deposition was evaluated using computed tomography scanning, and 18 fluorodeoxyglucose positron emission tomography images were acquired dynamically both in the fasted state and during a euglycemic-hyperinsulinemic clamp. Glucose uptake rates and pixel-wise modeled brain volumes were calculated together with brain connectivity. RESULTS: Whole-body insulin sensitivity was reduced by more than 50% in the obesity group. During insulin stimulation, whole-brain insulin-induced increased glucose uptake was unaltered in lean animals but increased markedly in the animals with obesity. The increased glucose uptake reflected an increase in the inward transfer without changes in phosphorylation or outward brain transport. Connectivity was increased in the animals with obesity CONCLUSIONS: Diet-induced obesity is associated with an increase in insulin-stimulated brain glucose uptake as a consequence of a larger inward transfer. These changes occurred together with an increased connectivity in reference to regions associated with memory recollection.
Authors: Eleni Rebelos; Andrea Mari; Marco Bucci; Miikka-Juhani Honka; Jarna C Hannukainen; Kirsi A Virtanen; Jussi Hirvonen; Lauri Nummenmaa; Martin Heni; Patricia Iozzo; Ele Ferrannini; Pirjo Nuutila Journal: Endocrinol Diabetes Metab Date: 2020-04-19
Authors: Eleni Rebelos; Marco Bucci; Tomi Karjalainen; Vesa Oikonen; Alessandra Bertoldo; Jarna C Hannukainen; Kirsi A Virtanen; Aino Latva-Rasku; Jussi Hirvonen; Ilkka Heinonen; Riitta Parkkola; Markku Laakso; Ele Ferrannini; Patricia Iozzo; Lauri Nummenmaa; Pirjo Nuutila Journal: Diabetes Care Date: 2021-01-14 Impact factor: 19.112