Vagal Nerve Stimulation and Glucose Metabolism
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ClinicalTrials.gov Identifier: NCT01117311 |
Recruitment Status :
Completed
First Posted : May 5, 2010
Results First Posted : January 6, 2014
Last Update Posted : January 6, 2014
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Condition or disease | Intervention/treatment | Phase |
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Type 2 Diabetes Obesity Gastric Emptying | Device: VNB on Device: VNB off | Not Applicable |
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. Though the vagal trunks are preserved during bariatric surgery, gastric transection during the formation of a gastric pouch for Roux-en-Y gastric bypass (RYGB), or during the sleeve gastrectomy for the duodenal switch procedure, may denervate post-gastric organs including the pancreas and intestine. Reversible vagal block results in weight loss, decreased caloric intake, earlier satiation and reduced hunger. The effect of this form of vagal denervation on glycemic control is unclear. There is evidence that hepatic parasympathetic input regulates insulin action in rodents. Vagal afferents are also important in hepatoportal glucose sensing.
Subjects enrolled into the study would be on stable Vagal Nerve Stimulation Blocker (VNB) intervention in excess of 12 months, having taken part in prior observational study examining the long-term effects of vagal inhibition. All subjects will be studied three times after using a mixed meal. Participants will be admitted to the Mayo Clinic Clinical Research Unit at 17.00 hours the evening before the study. Following ingestion of a standardized low calorie mixed meal (400 Kcal: 55% carbohydrate, 30% fat, and 15% protein) subjects will fast overnight. During the experiment subjects will undergo a mixed meal study as outlined below (Lead-in Mixed Meal 1). On the day after study, subjects will be randomized to one of 2 interventions: either discontinue use of the VNB or continue its use. Subjects will then be restudied (Mixed Meal 2) the day after admission to the Clinical Research Unit at 17.00 hours on the 13th day after randomization. To determine the metabolic effects, if any, of starting VNB therapy, on the day after study, VNB use will be resumed or discontinued depending on prior activation or inactivation. Subjects will then be restudied (Mixed Meal 3) the day after admission to the Clinical Research Unit at 17.00 hours on the 13th day after completion of Mixed Meal 2. Following completion of the study, VNB use will be resumed in all subjects.
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 9 participants |
Allocation: | Randomized |
Intervention Model: | Crossover Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Basic Science |
Official Title: | The Effect of Vagal Nerve Stimulation on Enteroendocrine Secretion and Glucose Metabolism |
Study Start Date : | March 2011 |
Actual Primary Completion Date : | June 2012 |
Actual Study Completion Date : | November 2012 |

Arm | Intervention/treatment |
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Experimental: VNB off first, then VNB on
Subjects assigned to this reporting group had the vagal nerve blocker (VNB) on for the lead in period (Mixed Meal 1), then VNB off first for the first intervention (Mixed Meal 2), then VNB on for the second intervention (Mixed Meal 3).
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Device: VNB on
The implanted Vagal Nerve Blocker will be on at the time of study. Device: VNB off The implanted Vagal Nerve Blocker will be off at the time of study. |
Experimental: VNB on first, then VNB off
Subjects assigned to this reporting group had the vagal nerve blocker (VNB) on for the lead in period (Mixed Meal 1), then VNB on first for the first intervention (Mixed Meal 2), then VNB off for the second intervention (Mixed Meal 3).
|
Device: VNB on
The implanted Vagal Nerve Blocker will be on at the time of study. Device: VNB off The implanted Vagal Nerve Blocker will be off at the time of study. |
- Disposition Index [ Time Frame: baseline, 2 weeks ]Total Disposition Index (DI) is a calculated value which represents the ability of a person's pancreas to lower blood glucose. A higher number means the pancreas is better able to lower blood glucose and a lower number means the pancreas is less able to lower blood glucose.
- Gastric Emptying Half-time [ Time Frame: approximately 2 hours after radiolabeled meal is ingested ]Gastric emptying half time is the time for half of the ingested solids or liquids to leave the stomach.

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Ages Eligible for Study: | 35 Years to 75 Years (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01117311
United States, Minnesota | |
Mayo Clinic in Rochester | |
Rochester, Minnesota, United States, 55905 |
Principal Investigator: | Adrian Vella, MD | Mayo Clinic |
Responsible Party: | Adrian Vella, Professor of Medicine, Mayo Clinic |
ClinicalTrials.gov Identifier: | NCT01117311 |
Other Study ID Numbers: |
09-008825 R01DK082396 ( U.S. NIH Grant/Contract ) UL1RR024150 ( U.S. NIH Grant/Contract ) |
First Posted: | May 5, 2010 Key Record Dates |
Results First Posted: | January 6, 2014 |
Last Update Posted: | January 6, 2014 |
Last Verified: | November 2013 |
Vagus Diabetes Obesity |
Obesity Overnutrition Nutrition Disorders Overweight Body Weight |