Glucose Intolerance, Insulin Resistance
Conditions
Brief summary
Two important mechanisms play a major role in the pathogenesis of type 2 diabetes: insulin resistance of the target tissues and the impaired insulin secretion from pancreatic β-cells. Postprandial factors (such as insulin) are perceived by the human brain and induce signals that regulate glucose metabolism via the parasympathetic nervous system. Transcutaneous auricular vagus nerve stimulation (tVNS) can be used on the outer ear to stimulate the auricular branch of the vagus nerve in humans. Heart rate variability (HRV) in healthy people can be significantly increased via tVNS, indicating a shift from sympathetic activity to parasympathetic activity. The hypothesis is that this postprandial shift results in a change in peripheral glucose metabolism. In turn, the increased parasympathetic activity could potentially result in a change in postprandial insulin sensitivity or secretion. To test this hypothesis, this study investigates the effect of vagal stimulation versus sham stimulation on insulin sensitivity, on insulin secretion, glucose tolerance, resting energy expenditure, and on parasympathetic tone (analysis of heart rate variability).
Interventions
Stimulation will be performed for 150 minutes (throughout the entire OGTT).
DEVICETransauricular sham stimulation
Sham stimulation will be performed for 150 minutes (throughout the entire OGTT)
Sponsors
University Hospital Tuebingen
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
MALE
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
* HbA1c \<6.5% * Must be able to understand the explanations of the study and the instructions
Exclusion criteria
* Any relevant (according to investigator's judgment) cardiovascular disease * Neurological and psychiatric disorders * Diabetes mellitus * Active implants (e.g. pacemaker, cochlear implant, cerebral shunt) * asthma * skin diseases on the ear
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Whole body insulin sensitivity | 0-120 min | Insulin sensitivity will be assessed by a 75g OGTT. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Insulin secretion | 0-120 min | Insulin secretion will be assessed by a 75g OGTT |
| Glucose tolerance | 0-120 min | Glucose tolerance will be assessed by a 75g OGTT |
| Resting energy expenditure | 140-160 min. after start of stimulation | Resting energy expenditure will be assessed by indirect calorimetry |
| Heart rate variability | -30 - 120 min | Heart rate variability will be assessed from continuous ecg recordings |
Countries
Germany
Outcome results
None listed