Metabolic Phenotyping in Humans (MetPhe)
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ClinicalTrials.gov Identifier: NCT01298375 |
Recruitment Status :
Recruiting
First Posted : February 17, 2011
Last Update Posted : September 19, 2022
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Condition or disease |
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Healthy Obesity Type 2 Diabetes Mellitus |
The aim of the present research proposal is to metabolically phenotype endurance trained athletes, lean and obese sedentary and type 2 diabetic individuals with the following objectives:
- assess metabolic flexibility as measured by a euglycemic-hyperinsulinemic clamp
- measure in vivo mitochondrial function by MRS of phosphocreatine (PCr) recovery
- establish primary myoblast cell lines to correlate with the above in vivo measurements, as well as further explore dietary, pharmacological and genetic manipulations in vitro
- quantify intramyocellular lipid (IMCL) and acetylcarnitine in vivo by MRS
Study population:
A total of 132 male participants (18-70 years) will participate in this study. The first group of 33 participants will be lean endurance-trained athletes, the second group will be lean sedentary control participants, the third group will be sedentary type 2 diabetic participants, and the last group of 33 participants will be obese, non-diabetic sedentary control participants. It is preferred to use male participants in order to minimize variation in the measurements by avoiding confounding factors such as hormones.
Main study parameters/endpoints: The main study parameters are differences in metabolic flexibility as measured by euglycemic-hyperinsulinemic clamp, PCr recovery, IMCL and acetylcarnitines as measured by MRS and establishment of primary myoblast cell lines for future use.
Study Type : | Observational |
Estimated Enrollment : | 132 participants |
Observational Model: | Cohort |
Time Perspective: | Cross-Sectional |
Official Title: | Metabolic Characterization of Type 2 Diabetic, Obese, Lean Sedentary and Endurance Trained Individuals in Vivo, ex Vivo and in Vitro |
Study Start Date : | March 2011 |
Estimated Primary Completion Date : | March 2024 |
Estimated Study Completion Date : | March 2024 |

- Euglycemic-hyperinsulinemic clamp for measurement of insulin sensitivity and metabolic flexibility [ Time Frame: 10 hours ]After taking fasting blood samples, a primed constant infusion of glucose is initiated. Plasma glucose levels are clamped at ~5 mmol/L by variable co-infusion of 20% glucose. Every 5 minutes, blood is sampled for immediate determination of plasma glucose concentration. Glucose infusion rate is adjusted to obtain plasma glucose levels of ~5 mmol/L (euglycemia). A bolus of insulin is then infused. Before and during steady state, substrate oxidation is measured using an indirect calorimeter, which determines metabolic flexibility.
- Evaluating mitochondrial function through measurement of phosphocreatine (PCr) recovery by phosphorus magnetic resonance spectroscopy (31P-MRS) within the skeletal muscle [ Time Frame: 1.5 hours ]The quantification of energy metabolites (Pi, PCr and ATP) in skeletal muscle will be performed in the v. lateralis at rest, during submaximal knee-extension exercise and during recovery. The rate at which PCr concentration is restored after exercise is an excellent in vivo measure of skeletal muscle mitochondrial oxidative capacity.
Biospecimen Retention: Samples With DNA

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Ages Eligible for Study: | 18 Years to 70 Years (Adult, Older Adult) |
Sexes Eligible for Study: | Male |
Accepts Healthy Volunteers: | Yes |
Sampling Method: | Non-Probability Sample |
General Inclusion criteria:
- Male sex
- Generally healthy with specifically no known cardiovascular disease or gastric ulcers, which can affect the study parameters
- Stable dietary habits (no weight loss/gain > 3 kg in the last 6 months)
Group 1, type 2 diabetes participants:
- Ages 40-70 years
- BMI > 30 kg/m2
- Non-insulin dependent type 2 diabetes
- Must be on sulphonylurea (SU)-derivate or metformin therapy for at least six months with a constant dose for at least two months, or on dietary treatment for at least six months
- Well-controlled diabetes: HbA1c < 8%
- No diabetes related co-morbidities like cardiovascular diseases, diabetic foot, polyneuropathy, retinopathy
Group 2, obese healthy control participants:
- Ages 40-70 years
- BMI > 30 kg/m2
- A plasma glucose level lower than 6.1 mmol/L
- No family history of diabetes
- No medication use
- Sedentary lifestyle; No participation in any physical activity for at least 2 years
Group 3, endurance trained athletes:
- Ages 18-35 years
- BMI < 25 kg/m2
- No family history of diabetes
- No medication use
- VO2max > 55ml/kg/min
- Active in competitive endurance-exercise activities, 3 times a week for at least 2 years
- Stable level of training for at least 6 months
Group 4, lean healthy sedentary control participants:
- Ages 18-35 years
- BMI < 25 kg/m2
- No family history of diabetes
- No medication use
- VO2max < 55ml/kg/min
- Plasma glucose < 6.1 mmol/L
- Sedentary lifestyle; No participation in physical activity for more than 1 hour per week for at least 2 years
General Exclusion criteria:
- Regular smokers
- Participation in other studies
- Female sex
- Insulin dependent diabetic individuals
- Participants with diabetes related diseases (diabetic foot, diabetic polyneuropathy, diabetic retinopathy etc.)
- Use of Thiazolidines (glitazone/rosiglitazone/pioglitazone/troglitazone)
- Use of anti-coagulants (not thrombocyte-aggregation inhibitors)
- Aberrant ECG (with signs of ischemia or cardiac failure or arrythmias)
- Weight gain/loss > 3 kg in the last 6 months
- HbA1c < 7.8 in type 2 diabetic individuals
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Contraindications for MRS scans:
- Electronic implants such as pacemakers or neurostimulator
- Iron-containing foreign bodies in eyes or brain
- Some hearing aids and artificial (heart) valves which are contraindicated for MRS
- Claustrophobia
- Participants, who do not want to be informed about unexpected medical findings, or do not wish that their physician be informed, cannot participate in the study.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01298375
Contact: Madeleen Bosma, M.S. | 31433884254 | m.bosma@maastrichtuniversity.nl | |
Contact: Bram Brouwers, B.S. | 31433884258 | b.brouwers@maastrichtuniversity.nl |
Netherlands | |
Maastricht University | Recruiting |
Maastricht, Limburg, Netherlands, 6200MD | |
Contact: Madeleen Bosma, M.S. 31433884254 m.bosma@maastrichtuniversity.nl | |
Principal Investigator: Lauren M Sparks, PhD | |
Principal Investigator: Madeleen Bosma, M.S. | |
Sub-Investigator: Vera Schrauwen-Hindeling, PhD |
Study Director: | Patrick Schrauwen, PhD | Maastricht University | |
Principal Investigator: | Lauren M Sparks, PhD | Maastricht University | |
Principal Investigator: | Madeleen Bosma, M.S. | Maastricht University |
Responsible Party: | Maastricht University Medical Center |
ClinicalTrials.gov Identifier: | NCT01298375 |
Other Study ID Numbers: |
NL35178.068.11 |
First Posted: | February 17, 2011 Key Record Dates |
Last Update Posted: | September 19, 2022 |
Last Verified: | September 2022 |
Metabolic flexibility Mitochondrial function Human primary myoblasts Lipid metabolism |
Diabetes Mellitus, Type 2 Diabetes Mellitus Glucose Metabolism Disorders Metabolic Diseases Endocrine System Diseases |