title: Differential Acute Impacts of Sleeve Gastrectomy, Roux-en-Y Gastric Bypass Surgery and Matched Caloric Restriction Diet on Insulin Secretion, Insulin Effectiveness and Non-Esterified Fatty Acid Levels Among Patients with Type 2 Diabetes.
abstract: Bariatric surgery is an increasingly common option for control of type 2 diabetes (T2D) and obesity. Mechanisms underlying rapid improvement of T2D after different types of bariatric surgery are not clear. Caloric deprivation and altered levels of non-esterified fatty acid (NEFA) have been proposed. This study examines how sleeve gastrectomy (SG), Roux-en-Y gastric bypass (GBP) or matched hypocaloric diet (DT) achieves improvements in T2D by characterising components of the glucose metabolism and NEFA levels before and 3 days after each intervention.
  
  
  
  Plasma samples at five time points during oral glucose tolerance test (OGTT) from subjects with T2D undergoing GBP (N = 11) or SG (N = 12) were analysed for C-peptide, insulin and glucose before surgery and 3-day post-intervention or after DT (N = 5). Fasting palmitic, linoleic, oleic and stearic acid were measured. C-peptide measurements were used to model insulin secretion rate (ISR) using deconvolution.
  
  
  
  Subjects who underwent GBP surgery experienced the greatest improvement in glycaemia (median reduction in blood glucose (BG) from basal by 29 % [IQR -57, -18]) and the greatest reduction in all NEFA measured. SG achieved improvement in glycaemia with lower ISR and reduction in all but palmitoleic acid. DT subjects achieved improvement in glycaemia with an increase in ISR, 105 % [IQR, 20, 220] and stearic acid.
  
  
  
  GBP, SG and DT each improve glucose metabolism through different effects on pancreatic beta cell function, insulin sensitivity and free fatty acids.
authors.affiliation: Department of Mechanical Engineering, University of Canterbury, Private Bag 8140, Christchurch, New Zealand. felicity.thomas@pg.canterbury.ac.nz.
authors.forename: Felicity
authors.identifier: 0000-0003-1299-2353
authors.initials: F
authors.lastname: Thomas
authors.affiliation: Department of Pharmacology, UNSW Australia, Kensington, 2033, Sydney, Australia.
authors.forename: Greg C
authors.initials: GC
authors.lastname: Smith
authors.affiliation: School of Applied Sciences and School of Interprofessional Health Studies, Faculty of Health and Environmental Sciences and Institute of Biomedical Technology, Auckland University of Technology, Private Bag 92006, Box A-25, Auckland, 1142, New Zealand.
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.affiliation: Department of General Surgery, Middlemore Hospital, Private Bag 93311, Otahuhu, Auckland, 1640, New Zealand.
authors.forename: Richard
authors.initials: R
authors.lastname: Babor
authors.affiliation: Department of General Surgery, Waitemata District Hospital Board, Shakespeare Rd, Takapuna, Auckland, New Zealand.
authors.forename: Michael
authors.initials: M
authors.lastname: Booth
authors.affiliation: Department of General Surgery, Auckland City Hospital, Park Rd, Grafton, Auckland, 1023, New Zealand.
authors.forename: Grant
authors.initials: G
authors.lastname: Beban
authors.affiliation: Department of Mechanical Engineering, University of Canterbury, Private Bag 8140, Christchurch, New Zealand.
authors.forename: J Geoffrey
authors.initials: JG
authors.lastname: Chase
authors.affiliation: Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand.
authors.forename: Rinki
authors.initials: R
authors.lastname: Murphy
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D031204:Caloric Restriction / Q000379:methods*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000601:surgery*; D004038:Diet, Reducing; D005227:Fatty Acids / Q000097:blood* / Q000378:metabolism; D005260:Female; D005743:Gastrectomy; D015390:Gastric Bypass; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism*; D007333:Insulin Resistance; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism; D008297:Male; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000601:surgery; D015431:Weight Loss / Q000502:physiology
chemical_list: D001786:Blood Glucose; D005227:Fatty Acids; D007328:Insulin
keywords: Insulin secretion; Non-esterified fatty acid; Obesity; Roux-en-Y gastric bypass; Sleeve gastrectomy; Type 2 diabetes; Very low calorie diet