Healthy Subjects
Conditions
Brief summary
Non-alcoholic fatty liver disease (NAFLD) is a common human liver pathology, closely associated with the obesity pandemic and insulin resistance. In the insulin resistant state the liver remains sensitive to pro-lipogenic signals of insulin, which further promote lipid accumulation. Secretion of very-low-density-lipoproteins (VLDL), the main carriers of triglycerides (TG) in the plasma, is the principal pathway for the liver to mobilize and dispose of lipids. Thus, hepatic TG export must not be too low in order to prevent steatosis. Our preliminary data from animal experiments suggest that enhanced brain insulin signaling promotes hepatic VLDL secretion, and reduces lipid accumulation in the liver. It remains to be tested whether other insulin sensitive tissues, such as the myocardium or the skeletal muscle, are also affected. In humans, neuropeptides, including insulin, can be delivered to the brain via an intranasal (IN) route of administration, without causing relevant systemic side effects. Therefore, we hypothesize that by enhancing brain insulin signaling using chronic IN insulin administration hepatic TG export increases and prohibits lipid accumulation in the liver and other insulin sensitive tissues, such as the myocardium and the skeletal muscle.
Interventions
DRUGIntranasal insulin administration
intranasal insulin (40 IE) Actrapid (100IE/mL); two 0.1 ml puffs per nostril) or placebo (insulin dilution buffer Novo Nordisk; two 0.1 ml puffs per nostril) four times a day (in total 160 IE Actrapid per day) before each main meal and before going to bed. 40 IE IN insulin enhances insulin concentration in the CSF without any changes in systemic insulin and glucose concentration, and no risk for hypoglycemia
DRUGInsulin Dilution Buffer (Novo Nordisk)
intranasal insulin (40 IE) Actrapid (100IE/mL); two 0.1 ml puffs per nostril) or placebo (insulin dilution buffer Novo Nordisk; two 0.1 ml puffs per nostril) four times a day (in total 160 IE Actrapid per day) before each main meal and before going to bed. 40 IE IN insulin enhances insulin concentration in the CSF without any changes in systemic insulin and glucose concentration, and no risk for hypoglycemia
OTHER1H magnetic resonance spectroscopy
1H MR spectroscopy and imaging will be performed on the on on the 3.0-T Tim Trio System (Siemens Erlangen Germany). MR Spectroscopy and imaging measurements will last no more than 90 minutes all together.
Sponsors
Medical University of Vienna
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
MALE
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* BMI 22 - 27 kg/m2 * Age between 18 - 65 years * Male sex
Exclusion criteria
* smoking * regular medication * metabolic or liver illnesses * tendency towards claustrophobia * Chronic sinusitis, diagnosed nasal polyposis, diagnosed severe septum deviation * metal devices or other magnetic material in or on the subjects body which will be hazardous for NMR investigation \[heart pacemaker, brain (aneurysm) clip, nerve stimulators, electrodes, ear implants, post coronary by-pass graft (epicardial pace wires), penile implants, colored contact lenses, patch to deliver medications through the skin, coiled spring intrauterine device, vascular filter for blood clots, orthodontic braces, shunt-spinal or ventricular, any metal implants (rods, joints, plates, pins, screws, nails, or clips), embolization coil, or any metal fragments or shrapnel in the body\].
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Changes in total lipid content in the liver | one week before & at baseline & 1,2,3 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes of hepatic Lipid composition | one week before & baseline & 1,2,3 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
| Changes of myocardial lipid content | baseline, 2 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
| Changes of myocardial lipid composition | baseline, 2 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
| Changes of lipid composition in skeletal muscle | baseline, 2 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
| changes in heart function | baseline, 2 and 4 weeks after intranasal insulin administration | magnetic resonance imaging |
| Changes of skeletal muscle lipid content | baseline, 2 and 4 weeks after intranasal insulin administration | 1H magnetic resonance spectroscopy |
Other
| Measure | Time frame | Description |
|---|---|---|
| Changes of parameters of glucose and lipid metabolism | one week before & baseline & 1,2,3 and 4 weeks after initiation of intranasal insulin administration | fasting Glucose, HbA1c, Cholesterol, LDL, HDL, TGs, non-HDL Cholesterol, FFAs |
| Lipid composition in plasma | one week before & at baseline & 1,2,3 and 4 weeks after intranasal insulin administration | — |
Countries
Austria
Outcome results
None listed