Longitudinal Multi-Omic Profiles to Reveal Mechanisms of Obesity-Mediated Insulin Resistance

Study Overview
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Brief Summary
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This 12-week controlled diet and weight intervention study seeks to define the molecular pathways that link excess body weight to the development of insulin resistance (IR). Blood, adipose and stool are sampled at three timepoints; baseline, peak weight (4 weeks) and post weight loss to monitor changes in cellular processes. Additionally, direct insulin sensitivity testing, and radiological measurement of visceral fat and intrahepatic fat content is measured at three timepoints to correlate clinical indices with cellular changes.

Detailed Description
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Obesity has become an epidemic worldwide. Metabolic/cardiovascular complications of obesity are likely related to the fact that obese individuals tend to be insulin resistant (IR). While insulin- mediated glucose uptake (IMGU) correlates with adipose tissue mass, not all obese individuals are IR, and metabolic and cardiovascular profiles of those who are IR vs insulin sensitive (IS) differ significantly. Why one individual who reaches a BMI of 30 kg/m2 will develop IR and another with similar BMI and activity level remains IS is unclear. Furthermore, while insulin sensitivity improves with weight loss, this response varies as well. Given that fat mass per se does not fully explain the obesity contribution to IMGU, itis likely that differential adipocyte function plays a role. With this study, our purpose is to employ an integrated omics strategy to identify analyte/pathway signatures in blood and adipose tissue that characterize IR versus IS states and expand our biological knowledge of the mechanisms underlying IR.

Official Title
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Longitudinal Multi-Omic Profiles to Reveal Mechanisms of Obesity-Mediated Insulin Resistance

Conditions
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Diabetes Mellitus, Type 2, PreDiabetes, Insulin Resistance, Obesity, Nonalcoholic Steatohepatitis, Nonalcoholic Fatty Liver, Diet Modification

Intervention / Treatment
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* Behavioral: Dietary Intervention Mediterranean Low Carbohydrate Diet
* Behavioral: Dietary Intervention Standard Low Carbohydrate Diet
* Behavioral: Dietary Intervention Standard Low Fat Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 35-65 BMI 25-35 kg/m2 Stable body weight Nondiabetic Exclusion Criteria: Patients with; diabetes major organ disease history of liposuction or bariatric surgery active eating or psychiatric disorder pregnancy or lactation, heavy alcohol use recent change in weight (over the past 12 weeks) use of weight loss medication, statins, or oral steroids Clinical screening exclusions; hematocrit < 33% fasting glucose >/= 126 mg/dL blood pressure >160/100 mmHg

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

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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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Mediterranean Low Carbohydrate Diet<br>Assigned participants will receive instruction by a registered dietitian on a diet that is high in unsaturated fats and low in carbohydrates. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks. | Behavioral: Dietary Intervention Mediterranean Low Carbohydrate Diet<br>* Assigned participants will receive instruction by a registered dietitian on a diet that is high in unsaturated fats and low in carbohydrates. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks.<br>|
| Experimental: Standard Low Carbohydrate Diet<br>Assigned participants will receive instruction by a registered dietitian on a low carbohydrate diet that is high in fats found in the typical American diet. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks. | Behavioral: Dietary Intervention Standard Low Carbohydrate Diet<br>* Assigned participants will receive instruction by a registered dietitian on a low carbohydrate diet that is high in fats found in the typical American diet. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks.<br>|
| Experimental: Low Fat, Healthy Carbohydrate Diet<br>Assigned participants will receive instruction by a registered dietitian on a low fat diet that is high in complex carbohydrates. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks. | Behavioral: Dietary Intervention Standard Low Fat Diet<br>* Assigned participants will receive instruction by a registered dietitian on a low fat diet that is high in complex carbohydrates. Total caloric intake will be adjusted to induce a supervised metabolic challenge defined as weight gain of approximately 2.5 kg over 5 weeks followed by 3-5kg weight loss over 8 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline on the 2-stage Steady State Plasma Glucose test | Compare direct measurement of insulin sensitivity after 4 week diet and weight intervention | Peak weight (4 weeks) | 
| Change from baseline on the radiographic measurement of visceral to subcutaneous (V:S) fat ratio | Compare measurement of abdominal V:S fat volume via computed tomography (CT) after 4 week diet and weight intervention | Peak weight (4 weeks) | 
| Change from baseline on the magnetic-resonance based measurement of intrahepatic lipid deposition | Compare measurement of liver fat content via magnetic resonance spectroscopy (MRS) after 4 week diet and weight intervention | Peak weight (4 weeks) | 
| Change from peak weight on the 2-stage Steady State Plasma Glucose test | Compare direct measurement of insulin sensitivity after 8 week diet and weight intervention | Post-weight loss (8 weeks) | 
| Change from baseline on the radiographic measurement of visceral to subcutaneous (V:S) fat ratio | Compare measurement of abdominal V:S fat volume via computed tomography (CT) after 8 week diet and weight intervention | Post-weight loss (8 weeks) | 
| Change from baseline on the magnetic-resonance based measurement of intrahepatic lipid deposition | Compare measurement of liver fat content via magnetic resonance spectroscopy (MRS) after 8 week diet and weight intervention | Post-weight loss (8 weeks) | 
| Measurement of markers of lipid and carbohydrate metabolism and inflammation from adipose mRNA | Compare adipose tissue transcripts such as known MODY transcription factors, defensin chemokine receptors, and platelet activation factors measured by PCR between participants identified as Insulin sensitive (IS) and Insulin resistant (IR) using the 2-stage Steady State Plasma Glucose test. | Baseline | 
| Quantification of plasma inflammatory cytokine levels in serum samples by Luminex immunoassay | Compare plasma inflammatory cytokine levels in serum samples as measured by Luminex immunoassay between participants identified as Insulin Sensitive (IS) and Insulin Resistant (IR) using the 2-stage Steady State Plasma Glucose test. | Baseline | 
| Change from baseline in plasma inflammatory cytokine levels in serum samples as measured by Luminex immunoassay | Compare intra-personal levels of plasma inflammatory cytokines as measured by Luminex immunoassay after 4 week diet and weight intervention | Peak Weight (4 weeks) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Metabolomics, Low Fat Diet, Low Carbohydrate Diet, Microbiome