TY - THES A1 - Rotzinger, Laura T1 - Roux-en-Y Magenbypass vermittelte Änderung der entereoinsulinären Achse : Quantifizierung der Effektgröße auf den Glukosestoffwechsel T1 - Roux-en-Y gastric bypass induced alteration of the entero-insulinar axis relevant impact on glucose control N2 - Nahrungsrestriktion und Gewichtsverlust stellen Schlüsselfaktoren in der Verbesserung der Insulinresistenz bei Patienten mit Adipositas-assoziiertem Diabetes mellitus Typ 2 dar. Es scheint, dass bariatrische Verfahren, insbesondere der Roux-en-Y Magenbypass Gewichtsabnahme-unabhängige Effekte auf die Verbesserung der Glukosetoleranz durch Änderung der enteroinsulinären Achse aufweisen. Die biologische Relevanz dieser Effekte ist bisher jedoch unzureichend untersucht. Daher wurden die Magenbypass-spezifischen Effekte von den rein Nahrungsrestriktiven in einem Model mit männlichen ZUCKER Ratten (fa/fa) abgegrenzt. Die Tiere wurden einem Magenbypass, einer Scheinoperation oder einer Scheinoperation mit anschließender Nahrungsrestriktion zugeführt. ZUCKER (fa/+) Ratten dienten als schlanke Kontrollgruppe. Um den Effekt der anatomischen und hormonellen Änderung nach Magenbypass auf den Glukosestoffwechsel, die ß-Zellfunktion und die Pankreasmorphologie zu quantifizieren wurde ein oraler Glukosetoleranztest mit Bestimmung der Glukose-, Insulin- und GLP-1- Plasmaspiegel durchgeführt. Zudem erfolgte eine immunhistologische Untersuchung der Langerhansinseln und die Bestimmung der GLP-1 und PDX-1 Expression. Die kombinierten biologischen, molekularen und histologischen Ergebnisse der Pankreasfunktion lassen vermuten, dass die Gewichtsabnahme prädominant in der Verbesserung der Glukosetoleranz nach Roux-en-Y Magenbypass und nicht die erhöhte GLP-1 Ausschüttung ist. N2 - Caloric restriction and body weight loss are key factors to improve insulin resistance in patients with type 2 diabetes associated with obesity. Bariatric surgery and especially, Roux-en-Y gastric bypass have been shown to cause weight loss independent effects on glucose control by altering the entero-insulinary axis in particular. Yet, their biological impact is not analysed sufficiently. Therefore we distinguished gastric-baypass spezific effects from caloric restriction alone in a modell with male ZUCKER (fa/fa) rats, who were randomised to either Roux-en-Y gastric bypass, sham surgery or sham surgery with following food restriction. ZUCKER (fa/+) rats were used as lean control group. To assess the impact of anatomical and hormonal alterations specific to gastric-bypass on glucose homeostasis, ß-cell function and pancreatic morphology an oral glucose tolerance test was performed and plasma levels of glucose, insulin and glucagon-like-peptide (GLP-1) were measured. Immunhistological analysis of pancreatic islets was performed and GLP-1 receptor and PDX-1 mRNA content were quantified. Combined biological, molecular and histological analyses of pancreatic funcion suggest that weight loss may be predominant in the improvement of glucose control after gastric bypass surgery and not the enhancement of GLP-1 responses. KW - Magenbypass KW - enteroinsulinäre Achse KW - Roux-en-Y KW - Zucker KW - gastric-bypass Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208271 ER - TY - JOUR A1 - Hankir, Mohammed K. A1 - Rotzinger, Laura A1 - Nordbeck, Arno A1 - Corteville, Caroline A1 - Dischinger, Ulrich A1 - Knop, Juna-Lisa A1 - Hoffmann, Annett A1 - Otto, Christoph A1 - Seyfried, Florian T1 - Leptin receptors are not required for Roux-en-Y gastric bypass surgery to normalize energy and glucose homeostasis in rats JF - Nutrients N2 - Sensitization to the adipokine leptin is a promising therapeutic strategy against obesity and its comorbidities and has been proposed to contribute to the lasting metabolic benefits of Roux-en-Y gastric bypass (RYGB) surgery. We formally tested this idea using Zucker fatty fa/fa rats as an established genetic model of obesity, glucose intolerance, and fatty liver due to leptin receptor deficiency. We show that the changes in body weight in these rats following RYGB largely overlaps with that of diet-induced obese Wistar rats with intact leptin receptors. Further, food intake and oral glucose tolerance were normalized in RYGB-treated Zucker fatty fa/fa rats to the levels of lean Zucker fatty fa/+ controls, in association with increased glucagon-like peptide 1 (GLP-1) and insulin release. In contrast, while fatty liver was also normalized in RYGB-treated Zucker fatty fa/fa rats, their circulating levels of the liver enzyme alanine aminotransferase (ALT) remained elevated at the level of obese Zucker fatty fa/fa controls. These findings suggest that the leptin system is not required for the normalization of energy and glucose homeostasis associated with RYGB, but that its potential contribution to the improvements in liver health postoperatively merits further investigation. KW - Roux-en-Y gastric bypass surgery KW - energy homeostasis KW - glucose homeostasis KW - fatty liver KW - leptin system KW - Zucker fatty fa/fa rats Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-239550 SN - 2072-6643 VL - 13 IS - 5 ER -