Gut Microbiota Post Roux-en-Y Gastric Bypass Surgery

Study Overview
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Brief Summary
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The purpose of this study is to investigate mechanisms responsible for weight change in patients who have undergone weight loss surgery. Specifically, we will compare the gut microbiota, plasma bile acids, plasma gut peptides (GLP-1, GLP-2, and PYY), and plasma LPS in three groups of subjects: 3-5 years post gastric bypass patients who experienced sub-optimal weight loss, 3-5 years post gastric bypass patients who had successful weight loss, and a control group who has not had a weight loss surgery and are of similar age, gender, body mass index as the gastric bypass groups.

Official Title
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The Gut Microbiota in Patients Post Roux-en-Y Gastric Bypass Surgery

Conditions
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Obesity

Intervention / Treatment
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* Other: Meal challenge


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female Age 18-65 3-5 years post Roux-en-Y gastric bypass and experienced successful weight loss following surgery (up to n=10) or 3-5 years post Roux-en-Y gastric bypass and did not experience optimal weight loss following surgery (up to n=10) or Nonsurgical control participants who are approximately matched in sex, age, and BMI to the optimal weight loss group (up to n=10). Exclusion Criteria: Tobacco use in past three months. Taking a medication which is known to significantly influence gastrointestinal transit time or affect the microbiome or other variables significantly (as determined by study pharmacist/MD). History of diabetes mellitus. Has taken an oral or IV/IM antibiotic in the past 3 months. Has taken probiotic and/or prebiotic agent in the past 3 months History of significant intestinal disease or disorder (e.g., Crohn's disease, ulcerative colitis, irritable bowel syndrome) History of gastrointestinal surgery that may impact measures of biological variables, as determined by the investigator. Medical condition expected to impact the biological variables of interest or interfere with providing a sample, as determined by the investigator. Unable to speak/read English. Breastfeeding, pregnant, or planning to become pregnant within the duration of the study. Unwilling to use a medically acceptable form of contraception. History of bipolar or psychotic spectrum disorder or alcohol or substance treatment in the past year

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Group 1 (Successful weight loss)<br>3-5 years post Roux-en-Y gastric bypass patients who had successful weight loss | Other: Meal challenge<br>* Participants will receive a liquid nutritional supplement. Before and after administration, biological variables of interest will be collected.<br>|
| Group 2 (Suboptimal weight loss)<br>3-5 years post Roux-en-Y gastric bypass patients who had suboptimal weight loss | Other: Meal challenge<br>* Participants will receive a liquid nutritional supplement. Before and after administration, biological variables of interest will be collected.<br>|
| Group 3 (Control group)<br>A control group who has not had Roux-en-Y gastric bypass surgery and are of similar age, gender, body mass index as the gastric bypass groups. | Other: Meal challenge<br>* Participants will receive a liquid nutritional supplement. Before and after administration, biological variables of interest will be collected.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intestinal Microbiome Composition. The ratio of firmicutes to bacteroidetes will be the primary focus of the microbiome evaluation. |  | 3-5 years post RYGB | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Plasma levels of cholic acid, chenodeoxy cholic acids, deoxycholic acid, and lithocholic acid will be measured by LCMS and will be compared between successful weight loss and poor weight loss post-RYGB and control groups. |  | 3-5 years post RYGB | 
| Plasma levels of GLP-1, GLP-2, and PYY will be measured by ELISA and will be compared between successful weight loss and poor weight loss post-RYGB and control groups. |  | 3-5 years post RYGB | 
| Plasma levels of Lipopolysaccharide (LPS) will be measured by the Limulus Amebocyte Lysate (LAL) assay and will be compared between successful weight loss and poor weigh loss post-RYGB and control groups. |  | 3-5 years post RYGB | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric Bypass, Gut Microbiota, Weight Regain