Biometabolic Outcomes After Weight Loss Surgery: An Individualized Approach
Biometabolic Outcomes After Weight Loss Surgery: An Individualized Approach
Variable outcomes after weight loss surgery are likely attributable to complex, poorly
 understood mechanisms. Due to the significant impact that morbid obesity has on a patient's
 health, successful management of obesity and its related comorbid medical conditions is
 important and thus necessitates continued improved therapies for treating obesity. Although
 the mechanisms of weight loss after surgical intervention are poorly understood, improved
 understanding of molecular and metabolic changes that occur after weight loss surgery may
 offer the ability to provide targeted precision therapy for patients with morbid obesity
 undergoing surgical therapy. In this proposal, we will combine a clinical trial whereby
 modifications to the gold-standard for weight loss surgery, the gastric bypass, are evaluated
 while simultaneously measuring molecular and metabolic changes that occur in response to
 these weight loss procedures. Through creating variable lengths of bypass intestine after
 gastric bypass, we will be able to determine the effect of malabsorption on clinical outcomes
 and mechanisms involved in weight loss after gastric bypass. We will also use two control
 groups. One will be a surgical weight loss control group and consist of patients undergoing a
 laparoscopic sleeve gastrectomy, a non-intestinal bypass procedure. The other group will
 consist of patients having non-surgical weight loss therapy. To asses metabolic changes that
 occur in response to surgical weight therapy and specifically intestinal bypass and
 malabsorption, we will examine changes in the gut microbiome and plasma gut enteroendocrine
 hormones. To evaluate molecular pathways that are impacted as a result of gastric bypass and
 malabsorption, we will measure circulating microRNAs (miRNAs) in the blood. Measurement of
 miRNAs will provide data on an easily measurable molecular marker for each treatment group.
 This is a first step in translational exploration of mechanisms of weight loss after surgery
 by evaluating both clinical and molecular/metabolic outcomes and begin an explorative process
 towards creating an individualized approach to improving outcomes after weight loss surgery.
Outcomes after weight loss surgery are quite variable with some patients regaining a
 significant amount of weight in the postoperative period. Increasing evidence suggests
 gastric bypass leads to weight loss and improvement in associated metabolic illness through
 mechanisms other than just restriction and malabsorption and may include circulating bile
 acids, gut hormones, genetic/epigenetic variability, changes in gut microbiota as well as
 other mechanisms. Whether modifications to bypassed intestine length may improve outcomes
 after gastric bypass has not been adequately studied with inconsistent results in the
 literature. Whether increasing the amount of bypassed intestine may positively amplify the
 multi-factorial mechanisms involved in successful weight loss has not been studied.

 The primary goal of the research is to determine if increasing the amount of bypassed
 intestine during gastric bypass surgery improves outcomes and effects molecular and metabolic
 changes that may impact outcomes after gastric bypass. The proposed research will evaluate
 not only biologic mechanisms of weight loss and correlation between these mechanisms and
 successful weight loss but also investigate the role intestinal bypass has on molecular and
 metabolic mechanisms involved in effective weight loss therapy. Regardless if weight loss
 outcomes are similar in patients with different lengths of bypassed intestine, the role of
 the gut in gastric bypass will be investigated through evaluation of gut microbiota,
 circulating miRNAs and gut hormones, three mechanisms thought to play a role in the
 effectiveness of the gastric bypass for weight loss surgery.

 Aim 1: Determine if increasing length of bypassed intestine leads to improved clinical
 outcomes after gastric bypass. A randomized-controlled trial design will be used with
 patients randomized to variable lengths of bypassed intestine when undergoing gastric bypass.
 A randomized trial will help avoid procedure selection bias. Surgical and non-surgical
 control groups will consist of patients having sleeve gastrectomy (non-intestinal bypass
 surgical control) and those undergoing best non-surgical, medical therapy. Primary outcomes
 measured will include weight loss and relief of medical comorbidities of obesity specifically
 diabetes and dyslipidemia. Secondary outcomes include complications related to malabsorption.

 Aim 2: Measure gut hormone changes after increased intestinal bypass during gastric bypass.
 We will measure gut hormones after variable amounts of intestinal bypass to determine the
 role of intestinal bypass in improvement of gut hormone production that affects metabolism,
 hunger and possibly weight loss. Blood collected from patient's in Aim 1 will be used to
 measure gut hormone levels which will then be correlated to clinical outcomes.

 Aim 3: miRNA profiling in patients having gastric bypass with variable intestinal bypass
 lengths. We will perform miRNA arrays on plasma from patients from Aim 1 to determine
 possible pathways impacted by weight loss and in particular increased intestinal bypass
 lengths in patients undergoing gastric bypass. The variable expression of miRNA will also be
 correlated to weight loss outcomes and metabolic disease improvement in the surgical
 patients.

 Aim 4: Measure variation in gut microbiome due to increased intestinal bypass during gastric
 bypass. We will examine the impact of weight loss and variable intestinal bypass lengths
 during gastric bypass on the gut microbiome. This will be determined through collection of
 stool samples preoperatively as well as postoperatively in patients having weight loss
 surgery. Samples will be collected from patients in Aim 1 above. Sleeve gastrectomy patients
 will be used to determine the impact of surgical weight loss on gut microbiome and variation
 in intestinal bypass lengths will provide insight into the role of bypassed intestine in the
 effects of gastric bypass on changes in gut microbiota after weight loss surgery. Through
 correlation with clinical outcomes we will be able to determine any association with weight
 loss and relief of metabolic disease when the gut microbiota are modified after weight loss
 surgery.

 Approach

 Protocol Aim 1: Determine if increasing length of bypassed intestine leads to improved
 clinical outcomes after gastric bypass.

 Primary outcomes will include weight loss and relief of medical comorbidities of obesity, in
 particular diabetes and dyslipidemia. Secondary outcomes include determining complications
 that occur such as protein calorie malnutrition, vitamin and micronutrient deficiencies and
 chronic diarrhea.

 1a. Randomization of patients and surgical technique. A total of five groups will be used.
 The surgical control group will consist of patients having a laparoscopic sleeve gastrectomy
 as described below under procedure descriptions. The non-surgical control group will include
 patients undergoing best medical therapy through our medical weight loss program. The other
 three groups will be randomized through a sealed-envelope method. The assigned group will be
 in a sealed envelope and the patient will be blinded to the treatment group that they are
 assigned to. Patients will be randomized to variable lengths of intestinal bypass during
 performance of a laparoscopic Roux-en-Y gastric bypass. See description of procedure below.
 These groups will function to examine the impact of increasing lengths of bypassed small
 intestine through modifications of the BPL length. The following three groups will be
 utilized:

 1. Alimentary limb length 100 cm and biliopancreatic limb length (true bypassed intestinal
 length) of 50 cm

 2. Alimentary limb length 100 cm and biliopancreatic limb length (true bypassed intestinal
 length) of 100 cm

 3. Alimentary limb length 100 cm and biliopancreatic limb length (true bypassed intestinal
 length) of 150 cm Sample size for randomization to the three gastric bypass groups will
 be approximately 75 patients in each group. 75 sleeve gastrectomy patients will also be
 included. Sample size was determined based on previously published literature. The total
 number of these patients will be used only for the clinical portion of the study. Sample
 size for this pilot study for each of the gut hormone assays, gut microbiome analyses
 and miRNA arrays will be 15 subjects in each group. This will include 15 patients
 selected from each of the groups of randomized gastric bypass patients, the sleeve
 gastrectomy group, and the medical control group for a total of 75 patients. Each
 patient will have stool and blood collected at pre-treatment (surgical or non-surgical
 therapy), 6 months post therapy and 12 months post therapy.

 Surgical Procedure A gastric bypass will be performed using our standard technique. In brief,
 all procedures will be performed laparoscopically as is standard practice. Specifically at
 our institution, the gastric pouch will be constructed with a linear stapler approximately 5
 cm long and 3 cm wide. The gastrojejunostomy anastomosis will be constructed either with a 25
 mm circular stapler or a linear stapler. The linear stapler common gastroenterotomy will be
 closed in a running 2 layer manner to narrow to approximately 13-15 mm. The jejunojeunostomy
 will be created with a liner stapler after creation of BPL length of 50 cm, 100 cm or 150 cm
 and an alimentary limb length of 100 cm which will be connected to the gastric pouch via the
 gastrojejunostomy. The remaining small bowel, which will represent the common small bowel
 channel will also be measured. Measurements will be achieved using premeasured markings on a
 laparoscopic grasper used to handle the small intestine.

 Patients undergoing a sleeve gastrectomy will serve as the control group in order to
 determine the effect that intestinal bypass has on the measured outcomes. The sleeve
 gastrectomy is performed laparoscopically to resect and remove approximately 80% by volume of
 the outer portion of the stomach. At our institution, specifically the sleeve gastrectomy is
 performed using multiple firings of a laparoscopic stapler using a bougie as an intraluminal
 template for sizing purposes. The bougie is either 36 or 40 French per our usual practice.

 2a. Sample collection preoperatively and postoperatively for metabolic and molecular studies.

 Sample Collection

 Samples will be collected and processed by the OneHealth Biorepository. The following samples
 will be collected in each patient:

 1. Blood: will be collected at a preoperative time point then at 6 months and 12 months
 postoperatively. The blood will be drawn by MU Health Care laboratories and transported
 by courier per standard protocol to the OneHealth Biorepository. It will be fractionated
 into its components and plasma collected and stored at -80℃ as previously described.

 2. Stool: Stool samples will be collected by patients at home using provided kits and
 mailed to the OneHealth Biorepository and stored, as previously described. Samples will
 be aliquoted and stored at -20℃.

 3a. Prospective collection of clinical data. Weight related data will be collected to
 determine effectiveness of weight loss operations. Weight data collected will include high
 weight when entering the weight loss surgery program, immediate preoperative weight collected
 on day of operation and postoperative weights at 1 week, 1 month, 3 months, 6 months and 12
 month follow-up appointments. Additional outcomes collected will include presence of diabetes
 mellitus with glycated hemoglobin (HgbA1C) levels measured preoperatively and at 6 and 12
 months postoperatively Remission of diabetes will be considered if the patient is off all
 anti-diabetic medications with a normal HgbA1C. Presence of preoperative dyslipidemia will
 also be documented to include abnormalities of LDL cholesterol, HDL cholesterol and
 triglyceride levels. Remission of dyslipidemia will be considered if preoperative abnormal
 levels of LDL and HDL cholesterol and triglycerides return to normal in the absence of
 lipid-lowering agents.

 Aim 2: Measure gut hormone changes after increased intestinal bypass during gastric bypass
 Millipore Human Metabolic Hormone Magnetic Bead Panel - Metabolism Multiplex Assay will be
 used to investigate a panel of gut hormones including GLP-1, GIP, leptin, PYY, and ghrelin.
 Plasma from 15 patients from each group (as described above) for a total of 75 total patients
 will be examined. Hormone levels in the plasma will be measured. Data will be analyzed both
 for intergroup differences as well as correlation with clinical outcomes will be performed.

 Aim 3: miRNA profiling in patients having gastric bypass with variable intestinal bypass
 lengths 15 patients from each group (as described above) for a total of 75 total patients
 will be examined. Plasma will be used to perform Affymetrix miRNA arrays to measure
 expression of all currently known miRNA. Corresponding pathways that miRNA affect will be
 identified using publicly available databases. Differences in miRNA expression between
 treatment groups will be compared. Differential levels of expression of miRNA will also be
 compared to clinical outcomes.

 Aim 4: Measure variation in gut microbiome due to increased intestinal bypass during gastric
 bypass.

 Stool samples will be collected as described above. They will be stored in the OneHealth
 Biorepository until processing. 15 patients from each group (as described above) for a total
 of 75 total patients will be examined. Composition of microbiota in each group will be
 determined as previously described. Comparison between treatment groups will be performed.
 Correlation to clinical outcome variables will be determined
Inclusion Criteria:

 1. Age greater than 18

 2. Body mass index of 40-60 kg/m2

 3. Meet insurance criteria, as set forth by the patient's insurance policy, to qualify
 for coverage for weight loss surgery

 4. Planned laparoscopic Roux-en-Y gastric bypass

 5. Willingness to have blood collected before and after surgical procedure at defined
 points and collect and mail stool sample before operation and at defined
 post-operative time points.

 Exclusion Criteria:

 1. Age less than 18

 2. Patient fails to fulfill insurance mandated criteria

 3. Unwilling to be randomized to variable length to gastric bypass or unwilling to have
 blood collected or personally collect and mail in stool sample

 4. Unwilling to follow-up at required postoperative visits