Factors governing gastrointestinal motility

Ullah, Sana


Thesis or dissertation

© 2012 Sana Ullah. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder.

Introduction: The reasons for the rapid resolution of diabetes (DM) following bariatric surgery in a significant proportion of patients with morbid obesity remain unclear. This thesis investigates the putative role of changes in gastrointestinal (GI) motility and GI hormones as well as the possible significance of alterations in energy expenditure that occur as a consequence of weight loss.

Methodology: My preliminary studies involved a systematic review of GI motility in obesity, and retrospective studies measuring GI motility with alternative methods including capsule endoscopy and hydrogen breath test. Subsequent to this I measured changes in GI motility in two very different patient cohorts; one following bariatric surgery for morbid obesity and the other a group of patients with proven gastroparesis treated with gastric neuromodulation (GNM). Parallel to the above I conducted studies of indirect calorimetry in these patients in an attempt to determine if changes in energy expenditure which occur as a consequence of weight loss were significant.

Results: In our prospective study temporary GNM significantly improved gastric emptying and nutritional intake.
There was conclusive evidence to causally relate alterations in GI motility and Glucagon like peptide -1 (GLP-1) with weight loss and resolution of DM following bariatric surgery.
An interesting "spin off" result of my studies was validation of capsule endoscopy (CE) as a means of assessing GI motility.
My results obtained from measure if indirect calorimetrty clearly show that standard equations tend to over estimate the energy requirements of this group. The implications of this are discussed.

1. Fast pouch emptying; an early and exaggerated GLP-1 response contributes in resolution of type 2 diabetes following RYGB.
2. GNM is an effective treatment for gastroparesis.
3. Capsule endoscopy may be used to assess GI motility.
4. Prediction equations over estimate energy requirements in morbidly obese patients.

Postgraduate Medical Institute, The University of Hull
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