title: Weight loss after bariatric surgery reverses insulin-induced increases in brain glucose metabolism of the morbidly obese.
abstract: Obesity and insulin resistance are associated with altered brain glucose metabolism. Here, we studied brain glucose metabolism in 22 morbidly obese patients before and 6 months after bariatric surgery. Seven healthy subjects served as control subjects. Brain glucose metabolism was measured twice per imaging session: with and without insulin stimulation (hyperinsulinemic-euglycemic clamp) using [18F]fluorodeoxyglucose scanning. We found that during fasting, brain glucose metabolism was not different between groups. However, the hyperinsulinemic clamp increased brain glucose metabolism in a widespread manner in the obese but not control subjects, and brain glucose metabolism was significantly higher during clamp in obese than in control subjects. After follow-up, 6 months postoperatively, the increase in glucose metabolism was no longer observed, and this attenuation was coupled with improved peripheral insulin sensitivity after weight loss. We conclude that obesity is associated with increased insulin-stimulated glucose metabolism in the brain and that this abnormality can be reversed by bariatric surgery.
authors.affiliation: Turku PET Centre, University of Turku and Turku University Hospital, Turku, Finland.
authors.forename: Jetro J
authors.initials: JJ
authors.lastname: Tuulari
authors.forename: Henry K
authors.initials: HK
authors.lastname: Karlsson
authors.forename: Jussi
authors.initials: J
authors.lastname: Hirvonen
authors.forename: Jarna C
authors.initials: JC
authors.lastname: Hannukainen
authors.forename: Marco
authors.initials: M
authors.lastname: Bucci
authors.forename: Mika
authors.initials: M
authors.lastname: Helmiö
authors.forename: Jari
authors.initials: J
authors.lastname: Ovaska
authors.forename: Minna
authors.initials: M
authors.lastname: Soinio
authors.forename: Paulina
authors.initials: P
authors.lastname: Salminen
authors.forename: Nina
authors.initials: N
authors.lastname: Savisto
authors.forename: Lauri
authors.initials: L
authors.lastname: Nummenmaa
authors.forename: Pirjo
authors.initials: P
authors.lastname: Nuutila
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015992:Body Mass Index; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000601:surgery; D011877:Radionuclide Imaging; D015431:Weight Loss / Q000502:physiology*
chemical_list: D007328:Insulin; D005947:Glucose