The Importance of Insulin Action in the Brain for the Immune System During Physical Activity-Overweight

Overview

The goal of this clinical trial is to clarify the interaction of central insulin action and physical activity with the immune system. Therefore, participants will undergo bicycle spiroergometer tests. This approach will be compared between days with insulin delivery to the brain as nasal spray and days with placebo spray. In another trial (NCT06552130) lean participants already have been tested. Significant effects on circulating cytokines could be identified. In this amendment, overweight persons in which brain insulin resistance is expected will be tested.

This research project aims to investigate if the brain insulin action regulates the immune system via the autonomous nervous system during physical activity and investigate whether participants with overweight respond different compared to lean persons. The lean persons were already studied in another trial (NCT06552130) and this trial serves as an amendment. Insulin action in the brain will be introduced by application of insulin as nasal spray (on one day) versus carrier solution as placebo nasal spray (on another day) in a randomized, blinded fashion. Spray administration will be performed 30 minutes before a 60 min bicycle spiroergometer test at 70 % VO2max that will introduce a postprandial state. On placebo day, the known spillover of tiny amounts of nasal insulin into the systemic circulation will be mimicked by an appropriate i.v. insulin bolus. Using this approach, brain-derived regulation of the immune system including the stimulation of immune cells via cytokines, physical performance, activity of the autonomous nervous system and gene-expression of leukocytes will be examined.