Glucose Metabolism, NAFLD (Nonalcoholic Fatty Liver Disease)
Conditions
Brief summary
This observational study aims to quantify whole-body amino acid and glucose metabolism in healthy adults and in patients with non-alcoholic fatty liver disease (NAFLD) using total-body PET/CT. The study investigates how orally and intravenously administered PET tracers (18F-FDG and 18F-FET) are absorbed in the gastrointestinal tract, distributed across major organs, and metabolized in different physiological and pathological states. A further objective is to examine how glucagon, during a pancreatic clamp using somatostatin, influences amino acid metabolism in healthy individuals and whether this response is altered in patients with NAFLD. Participants will be healthy volunteers or patients with NAFLD, aged 18-70 years. Depending on study group, participants will undergo one or more total-body PET/CT scans following oral or intravenous tracer administration, and in some cases receive glucagon or placebo infusion. Blood samples will be collected during scanning to assess hormone levels and metabolic responses. Data from these imaging sessions will be used to characterize nutrient metabolism, compare oral and intravenous tracer kinetics, and explore glucagon-induced metabolic changes across study groups.
Interventions
DRUG18F-FDG (oral)
Oral administration of 18F-fluorodeoxyglucose (\^18F-FDG) for total-body PET/CT to assess gastrointestinal absorption, systemic biodistribution, and whole-body glucose metabolism.
DRUG18F-FDG (intravenous)
Intravenous bolus administration of 18F-fluorodeoxyglucose (18F-FDG) for total-body PET/CT to measure systemic biodistribution and whole-body glucose metabolism.
DRUG18F-FET (oral)
Oral administration of O-(2-\[18F\]fluoroethyl)-L-tyrosine (18F-FET) for total-body PET/CT to assess gastrointestinal amino acid absorption and whole-body amino acid metabolism.
DRUG18F-FET (intravenous)
Intravenous bolus administration of O-(2-\[18F\]fluoroethyl)-L-tyrosine (18F-FET) for total-body PET/CT to measure systemic amino acid biodistribution and dynamic metabolic kinetics.
DRUGGlucagon
Continuous intravenous glucagon infusion to stimulate hepatic amino acid metabolism during a pancreatic clamp.
DRUGSomatostatin
Continuous intravenous somatostatin infusion to suppress endogenous pancreatic hormone secretion during the pancreatic clamp.
Intravenous infusion of isotonic sodium chloride solution used as placebo during crossover comparison with glucagon infusion.
OTHEROral Glucose Tolerance Test
Standard oral glucose load (75 g in 250 mL water) to assess glucose-stimulated metabolic responses during PET/CT.
Sponsors
Rigshospitalet, Denmark
Study design
Allocation
NON_RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Age 18-70 years * Body mass index (BMI) 20-27 kg/m2
Exclusion criteria
* Pregnancy * Claustrophobia * Inability to give consent due to psychological or other causes * Inability to speak/read Danish * Diabetes, cancer (active or treated within the last five years) or inflammatory diseases. * Low albumin * Chronic disorders that require medical treatment
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Whole-body tracer uptake (SUVmean) assessed using total-body PET/CT | 0-180 minutes after tracer administration |
Countries
Denmark
Outcome results
None listed