Hypothalamic Functional Magnetic Resonance Imaging (fMRI) Response to Nutrients

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to identify how certain parts of the brain that control appetite respond to changes in dietary carbohydrate and fat.

Detailed Description
-----------------
To measure fMRI signal change in hypothalamic and brainstem centers associated with control of food intake and energy expenditure in response to IV glucose, fructose, and saline. The fMRI response to these nutrients will then be compared in obese vs. lean subjects. Frequently timed blood samples will be obtained for measurement of nutrients (i.e., glucose) and blood levels of other factors (i.e., insulin, ghrelin, lactate) during these infusion protocols, and to test associations between these levels and the fMRI response.

Official Title
-----------------
Hypothalamic fMRI Response to Nutrients

Conditions
-----------------
Obesity

Intervention / Treatment
-----------------
* Dietary Supplement: glucose
* Dietary Supplement: fructose
* Dietary Supplement: saline


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Age 18 year to 45 years of age BMI 18 to 25 kg/m2 (25 subjects) and 30 to 40 kg/m2 (25 subjects), matched for age and sex. At maximal lifetime weight. Weight stable for at least 3 months. Exclusion Criteria: Those with a major medical illness or who require prescription medication, including: cancer, coronary artery disease, hypertension, and diabetes. Subjects taking psychiatric or centrally-acting (CNS) medications, or who are diagnosed with a psychiatric or neurological illness, including: depression, anorexia, bulimia, and seizure disorder. Subjects who have lost weight as a result of dieting, pharmacological treatment, or bariatric surgery. Weight > 350 lbs or girth > 60 inches (the limits of the MR machine) Exercise > 30 minutes, 3 times a week. Alcohol consumption > 2 drinks / day. Weight > 300 lbs (150 kg) (weight limit for MR machine). Blood glucose > 100 mg/dL, abnormal creatinine or liver function tests. Illicit drug use. Pregnancy. Extreme dietary habits as determined by a GCRC nutritionist: very high or low dietary carbohydrate, protein, or fat intakes. Those with a contraindication to exposure to strong magnetic fields: presence of metal in the body such as body piercing, shrapnel, cardiac pacemakers or aneurysm clips. Those with claustrophobia.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Participants will receive infusions of glucose, fructose, and saline in a randomized order.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Glucose<br>IV glucose | Dietary Supplement: glucose<br>* 0.3mg/kg of glucose<br>|
| Active Comparator: Fructose<br> | Dietary Supplement: fructose<br>* fructose IV bolus<br>|
| Placebo Comparator: Saline<br> | Dietary Supplement: saline<br>* IV saline<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The primary outcomes of this aim will be the change in fMRI response in the hypothalamus to IV glucose, to IV glucose during intralipid infusion, and to the IV glucose alone, in the lean and obese groups separately. |  | 0,1,2 and 3 months | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Obesity