Hepatic Mitochondrial Function in Youth

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

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT03587727

Acronym

MANGO

Enrollment

Registered

2018-07-16

Start date

2018-11-20

Completion date

2023-06-21

Last updated

2025-10-10

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Adolescent Obesity, Bariatric Surgery Candidate, Hepatic Steatosis, Obesity

Keywords

bariatric surgery, hepatic mitochondria, insulin secretion

Brief summary

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

Detailed description

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.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

13 Years to 20 Years

Healthy volunteers

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

Design outcomes

Primary

Measure	Time frame	Description
Change in Percentage of Liver Fat Per MRI	Prior to bariatric surgery and 1 year post-bariatric surgery	Percentage of liver fat at 1 year post-bariatric surgery minus percentage of liver fat prior to bariatric surgery. Liver fat measured with MRI and calculated via the Dixon method as the proton density hepatic fat. A negative value means a decrease in liver fat after bariatric surgery.
Change in %Direct TG-Glycerol Appearance	Prior to bariatric surgery and 1 year post-bariatric surgery	Change in %TG-Glycerol appearance from a labeled glycerol drink via direct pathway. TCA substrate cycling assessed via change in fractional direct glycerol carbon contributions to newly synthesized triglycerides using a U-13C glycerol tracer drink. A higher direct percentage is beneficial, indicating decreased oxidative stress resulting from excess glycerol metabolism through the TCA cycle.

Secondary

Measure	Time frame	Description
Change in Minimum Glucose	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Minimum glucose concentration (mg/dL) during 4 hour MMTT with 16 time points.
Change in Peak Insulin	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Peak insulin concentration (uIU/mL) during 4 hour MMTT with 13 time points.
Change in Minimum Insulin	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Minimum insulin concentration (uIU/mL) during 4 hour MMTT with 13 time points.
Change in Peak C-peptide	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Peak c-peptide concentration (ng/mL) during 4 hour MMTT with 10 time points.
Change in Insulin Sensitivity	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): measured with SI. This is a measure of post-prandial (MMTT) insulin sensitivity as calculated with the Oral Minimal Model (OMM) using SAAM II Software. This software uses participant weight, glucose and insulin concentrations at various time points during the MMTT to calculate the participant insulin sensitivity. A positive Si value means an increase in insulin sensitivity.
Change in Fasting Glucagon	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMT): Fasting glucagon concentration (pg/mL) at the beginning of a 4 hour MMTT 1 year post bariatric surgery minus prior to surgery. A negative value means there was a decrease in fasting glucagon concentrations one year post-bariatric surgery.
Change in Liver Stiffness Per MRI	Prior to bariatric surgery and 1 year post-bariatric surgery	Change from baseline in degree of hepatic stiffness, measured with Magnetic Resonance elastography (MRE).
Mitochondrial Function in the Liver Assessed by Oroboros	At the time of surgery	L/E Coupling Control Ratio: Maximal respiratory capacity was examined in permeabilized hepatic tissue from adolescents using pyruvate (carbohydrate) and palmitoylcarnitine (lipid) as a substrate. Respiratory capacity was normalized to hepatic tissue wet weight. Coupling control ratio (L/E) was calculated as oxygen flux in leak (oligomyocin) divided by ET capacity (FCCP) with a maximum coupling of 1.0.
Hepatic Steatosis Score Via Tissue Biopsy	At the time of surgery	NAFLD (non-alcoholic fatty liver disease) Activity Score (NAS) determined via liver tissue biopsy and graded by a pathologist. The NAS can range from 0 to 8 and is calculated by the sum of scores of steatosis (0-3), lobular inflammation (0-3) and hepatocyte ballooning (0-2). A higher number represent a worse outcome.
Change in Peak GLP-1	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Peak GLP-1 concentration (pmol/L) during 4 hour MMTT with 9 time points.
Change in Peak Glucose	Prior to bariatric surgery and 1 year post-bariatric surgery	Mixed meal tolerance test (MMTT): Peak glucose concentration (mg/dL) during 4 hour MMTT with 16 time points.

Countries

United States

Participant flow

Participants by arm

Arm	Count
Teenagers 13-20 Years Old in Bariatric Surgery Program 13-20 year old male and female participants before and after bariatric surgery.	20
Total	20

Withdrawals & dropouts

Period	Reason	FG000
Overall Study	10 did not complete either of the pre-op MMTT or post-op MMTT.	10
Overall Study	4 completed the pre-op MMTT but did not complete the post-op MMTT.	4

Baseline characteristics

Characteristic	Teenagers 13-20 Years Old in Bariatric Surgery Program
Age, Continuous	16.85 years STANDARD_DEVIATION 1.576
Ethnicity (NIH/OMB) Hispanic or Latino	12 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	8 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants
Race (NIH/OMB) American Indian or Alaska Native	1 Participants
Race (NIH/OMB) Asian	0 Participants
Race (NIH/OMB) Black or African American	3 Participants
Race (NIH/OMB) More than one race	1 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants
Race (NIH/OMB) Unknown or Not Reported	1 Participants
Race (NIH/OMB) White	14 Participants
Region of Enrollment United States	20 participants
Sex: Female, Male Female	13 Participants
Sex: Female, Male Male	7 Participants

Adverse events

Event type	EG000 affected / at risk
deaths Total, all-cause mortality	0 / 20
other Total, other adverse events	0 / 20
serious Total, serious adverse events	0 / 20

Outcome results

Primary

Change in %Direct TG-Glycerol Appearance

Change in %TG-Glycerol appearance from a labeled glycerol drink via direct pathway. TCA substrate cycling assessed via change in fractional direct glycerol carbon contributions to newly synthesized triglycerides using a U-13C glycerol tracer drink. A higher direct percentage is beneficial, indicating decreased oxidative stress resulting from excess glycerol metabolism through the TCA cycle.