Meal-induced Thrombin Generation Before and After Gastric Bypass

Study Overview
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Brief Summary
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The purpose of this study is to investigate harmful effects of intentional weight loss. Intentional weight loss has been linked to increased risk of cardiovascular disease in overweight individuals, but the link between intentional weight loss and thrombotic disease is poorly understood. Postprandial coagulation activation, including thrombin generation, is a potential mechanism after high-fat meals. Thirty obese patients admitted to gastric bypass will be included in a randomized, cross-over clinical trial. All patients will consume a high-fat meal and a low-fat meal served in a randomized order on two study days (two to seven days apart). This cross-over study will be carried out before weight loss, during lifestyle-induced weight loss, and during weight loss 3-4 months after gastric bypass. Fasting and postprandial blood samples are collected on each study days, while one fecal sample is collected for each study period. The study will contribute to our understanding of mechanisms underlying harmful effects of weight loss, and future, dietary guidelines in relation to intentional weight loss programs must be modified.

Official Title
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Meal-induced Thrombin Generation in Obese Women and Men Before and After Gastric Bypass - a Model of Intentional Weight Loss

Conditions
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Morbid Obesity, Weight Loss

Intervention / Treatment
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* Dietary Supplement: Experimental diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Eligible for gastric bypass surgery Exclusion Criteria: Use of anticoagulants, platelet inhibitors and oral contraceptives Known liver diseases, any malignant disorders, or known coagulation diseases

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will consume a high-fat meal and a low-fat meal served seperately in a randomized order on two seperate days (two-seven days apart)
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Group A (Cross-over Group 1)<br>Subjects randomly assigned to two experimental diets. This arm will receive high-fat meals first, followed by a washout period of two-seven days and then low-fat meals. | Dietary Supplement: Experimental diet<br>* The intervention will run concurrently with the gastric bypass treatment at the hospital. The first intervention is carried out before weight loss, and the intervention is repeated two times concurrently with two periods of weight loss (lifestyle and gastric bypass)<br>|
| Experimental: Group B (Cross-over Group 2)<br>Subjects randomly assigned to two experimental diets. This arm will receive low-fat meals first, followed by a washout period of two-seven days and then high-fat meals. | Dietary Supplement: Experimental diet<br>* The intervention will run concurrently with the gastric bypass treatment at the hospital. The first intervention is carried out before weight loss, and the intervention is repeated two times concurrently with two periods of weight loss (lifestyle and gastric bypass)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postprandial peak mean of prothrombin fragment 1+2 concentrations | Blood samples are collected after high-fat and low-fat meals on two study days. | Measures before weight loss, change from baseline to after lifestyle-induced weight loss and 4 months post-surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postprandial peak mean of cardiovascular risk markers concentrations | Blood samples are collected after high-fat and low-fat meals on two study days. | Measures before weight loss, change from baseline to after lifestyle-induced weight loss and 4 months post-surgery. | 
| Laboratory tests of fecal samples | Bacterial components of fecal samples | Measures before weight loss, change from baseline to after lifestyle-induced weight loss and 4 months post-surgery. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric Bypass