Weight loss and incretin responsiveness improve glucose control independently after gastric bypass surgery.
BACKGROUND
The aim of the present study was to determine the mechanisms underlying Type 2 diabetes remission after gastric bypass (GBP) surgery by characterizing the short- and long-term changes in hormonal determinants of blood glucose.


METHODS
Eleven morbidly obese women with diabetes were studied before and 1, 6, and 12 months after GBP; eight non-diabetic morbidly obese women were used as controls. The incretin effect was measured as the difference in insulin levels in response to oral glucose and to an isoglycemic intravenous challenge. Outcome measures were glucose, insulin, C-peptide, proinsulin, amylin, glucagon, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1) levels and the incretin effect on insulin secretion.


RESULTS
The decrease in fasting glucose (r = 0.724) and insulin (r = 0.576) was associated with weight loss up to 12 months after GBP. In contrast, the blunted incretin effect (calculated at 22%) that improved at 1 month remained unchanged with further weight loss at 6 (52%) and 12 (52%) months. The blunted incretin (GLP-1 and GIP) levels, early phase insulin secretion, and other parameters of β-cell function (amylin, proinsulin/insulin) followed the same pattern, with rapid improvement at 1 month that remained unchanged at 1 year.


CONCLUSIONS
The data suggest that weight loss and incretins may contribute independently to improved glucose levels in the first year after GBP surgery.
Bose
Mousumi
M
New York Obesity Research Center, St Luke’s/Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, New York, USA.
Teixeira
Julio
J
Olivan
Blanca
B
Bawa
Baani
B
Arias
Sara
S
Machineni
Sriram
S
Pi-Sunyer
F Xavier
FX
Scherer
Philipp E
PE
Laferrère
Blandine
B
D052242:Adiponectin / Q000097:blood; D000328:Adult; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D005215:Fasting; D005260:Female; D015390:Gastric Bypass; D005934:Glucagon / Q000097:blood; D052216:Glucagon-Like Peptide 1 / Q000097:blood; D005951:Glucose Tolerance Test; D006801:Humans; D054795:Incretins / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D020738:Leptin / Q000097:blood; D008875:Middle Aged; D009767:Obesity, Morbid / Q000150:complications / Q000601:surgery*; D011184:Postoperative Period; D013270:Stomach / Q000601:surgery*; D015431:Weight Loss / Q000502:physiology*
D052242:Adiponectin; D001786:Blood Glucose; D054795:Incretins; D007328:Insulin; D020738:Leptin; D052216:Glucagon-Like Peptide 1; D005934:Glucagon