Devon Hawkins, MD, Balakrishna Prasad, PhD, Rebekah Johnson, MD, Matthew Pierotti, MD, William Sherman, MD, Byron Faler, MD, Yong Choi, MD. Eisenhower Army Medical Center
Background: Sleeve gastrectomy is regarded as an effective intervention for both obesity and comorbid conditions such as diabetes. However, the mechanisms underlying diabetes remission after sleeve gastrectomy are not well understood. Several studies in Roux-en-Y gastric bypass patients suggest that increased incretin response and insulin secretion are responsible for improved glycemic control after surgery. The majority of the studies have focused on post-surgical changes in plasma concentration of GIP and GLP-1. However, the roles of different hormones produced by enteroendocrine L-cells and insulin sensitivity after sleeve gastrectomy have yet to be defined.
Objectives: The main goal of this study is to demonstrate similar effects of sleeve gastrectomy as Roux-en-Y gastric bypass on hormones produced by L cells (GLP1, PYY, and glicentin) as well as demonstrate similar increases in insulin sensitivity (measured by HOMA-IR, NEFA (non-esterified fatty acid), and phosphate concentration).
Methods: This was a prospective study of endocrine and metabolite responses to mixed meal ingestion (n=8-15). Before surgery patients were given a mixed meal challenge (8 oz Boost high protein milk shake), and blood samples were collected at time 0, 30, 60, 90, 120 min postprandial. Two weeks after surgery the same mixed meal challenge and sample collection was performed at the same time intervals. EDTA, aprotinin, and DPP IV inhibitor were added to blood prior to plasma separation. Plasma was then stored at -80C until assayed for hormones or metabolites. All hormones were analyzed by ELISA assays while metabolites were analyzed by HPLC-MS-MS analysis.
Results: Prior to surgery GLP1 increases with mixed meal ingestion. After sleeve gastrectomy GLP1 response had a 6.1-fold increase compared to preoperative values (p< 0.01). The two other hormones studied (PYY and glicentin) demonstrated similar increases in postsurgical response. Postsurgical changes in whole body sensitivity, measured by HOMA-IR, were not significantly changed. NEFA and phosphate clearance is used as a surrogate marker for insulin sensitivity in adipose cells and skeletal muscle, respectively. The rate of NEFA clearance was unchanged after surgery. The rate of phosphate clearance is significantly increased after surgery (P < 0.01).
Conclusion: The data suggests that sleeve gastrectomy leads to an increase in insulin sensitivity in skeletal muscle after surgery, in absence of changes in total insulin sensitivity, at early post-surgical period (2 weeks). Future studies are required to address the significance of these changes and the underlying biochemical mechanisms.
Presented at the SAGES 2017 Annual Meeting in Houston, TX.
Abstract ID: 79083
Program Number: MSS11
Presentation Session: Full-Day Military Surgical Symposium – Basic Science Presentations
Presentation Type: MSSPodium