Hepatic Mitochondrial Function in Youth

Hepatic Fat Content and Mitochondrial Flux in Obese Youth Before and After Bariatric Surgery

Assess the impact of bariatric surgery on hepatic energy metabolism and glucose and insulin dynamics in obese youth

A metabolic study that will be performed prior to and 12 months following bariatric surgery. The study will include 31-phosphorus magnetic resonance spectroscopy to measure phosphate concentrations in the liver; a 4 hour mixed meal tolerance test, an intravenous arginine test, Abdominal Magnetic Resonance Imaging (MRI) for visceral and hepatic fat, Magnetic Resonance (MR) Elastography of the liver, indirect calorimetry, body composition assessment with Bodpod, serum metabolomics and hepatic tissue mitochondrial measures from the time of surgery only.

Inclusion Criteria:

1. Obese youth ages 13-20 years, scheduled for bariatric surgery at Children's Hospital Colorado
2. BMI 35-55 m2/kg
3. Maximal body circumference <200 cm

Exclusion Criteria:

1. Use of medications known to affect insulin sensitivity: oral glucocorticoids within 10; days, atypical antipsychotics, immunosuppressant agents, HIV medications.
2. Infectious hepatitis
3. Alcohol abuse
4. Mitochondrial disease
5. Type 2 diabetes
6. Medications that affect hepatic outcomes (e.g. PPAR-γ or PPAR-α, metformin)
7. Currently pregnant or breastfeeding women. Development of pregnancy during the study period will necessitate withdrawal from the study.
8. Severe illness requiring hospitalization within 60 days
9. Diabetes, defined as Hemoglobin A1C > 6.4%
10. Anemia, defined as Hemoglobin < 10 mg/dL
11. Diagnosed major psychiatric or developmental disorder limiting informed consent
12. Implanted metal devices that are not compatible with MRI