Adjustable Gastric Banding and Its Effects on Postprandial Glucose Metabolism Independent of Weight Loss
Condition: Obesity; Diabetes
MeSH terms: Weight Loss
Study type: Interventional
Phase: Phase 4

Summary: 
      The overall aim is to determine the mechanism(s) by which common bariatric surgical
      procedures alter carbohydrate metabolism. Understanding these mechanisms may ultimately lead
      to the development of novel interventions for the prevention and treatment of Type 2 diabetes
      and obesity.
    

Detailed description: 
      The overall aim of this application is to determine the mechanism(s) by which common
      bariatric surgical procedures alter carbohydrate metabolism. Very often, resolution of
      diabetes occurs in the early post-operative period prior to the development of significant
      weight loss. It has been suggested that bariatric surgery alters insulin action but few
      studies have examined insulin secretion or postprandial glucose fluxes in such patients. At
      the present time, little is known about how the various bariatric surgical procedures alter
      glucose homeostasis. It is essential that the effect of bariatric surgery and meal size on
      these parameters be understood and accurately measured. Enteroendocrine secretion is affected
      by the rate of intestinal delivery of calories and may also be modulated by the enteric
      nervous system and the rate of direct delivery of nutrients to enteroendocrine cells. Direct
      measurement of intestinal transit is also an important part of understanding how bariatric
      surgery alters intestinal secretion of hormones that may alter glucose metabolism. The Oral
      and C-peptide Minimal Models when applied to C-peptide, glucose and insulin concentrations
      after ingestion of a standard labeled mixed meal can accurately measure insulin secretion and
      action. Subsequently, the disposition index provides a measurement of the appropriateness of
      insulin secretion for the prevailing insulin action. When coupled with established
      triple-tracer methodology, a mixed meal can be used to measure fasting and postprandial
      glucose fluxes. The present experiments will determine the mechanism of glucose lowering
      after adjustable gastric banding (AGB). AGB seems to be superior to medical therapy in type 2
      diabetes. However, bariatric surgery was not compared to intensive efforts at weight
      reduction which itself ameliorates diabetes and cardiovascular risk. It is therefore unknown
      if the beneficial effects of AGB on glucose metabolism are related to weight-loss per se
      rather than a direct effect of AGB.
    

Intervention name(s): Adjustable gastric banding; Dietary and lifestyle modification
Intervention type(s): Procedure; Behavioral
Intervention description(s): Placement of adjustable gastric band - laparoscopically; Dietary and lifestyle modification
Subjects will meet with a dietitian and a psychologist on a weekly basis and consume a diet matched to that of the banding arm
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science