Physiological Assessment of the Endothelium - Circadian Rhythm and Role of the Sympathetic Nervous System (PAN)
The purpose of this study is to determine whether interventions aimed at increasing sympathetic tone modify endothelial function measures as assessed by the measurement of flow-mediated dilation (FMD) and constriction (FMC). The investigators hypothesize that the three interventions under study will increase FMC while causing a blunting in FMD.
Further, the investigators plan to study the circadian variability of FMC and FMD. The investigators hypothesize a peak of FMD in the late hours of the day and a peak of FMC in the early hours.
|Endothelial Function||Procedure: Mental stress Other: no intervention Procedure: Myogenic activation Procedure: Cold pressure test|
|Study Design:||Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
|Official Title:||Studies on the Physiological Meaning of Flow-mediated Constriction, Flow-mediated Dilatation and Vasomotion/Flowmotion: Circadian Variability and Role of the Sympathetic Nervous System.|
- Change in FMD in response to sympathetic activation [ Time Frame: Change in FMD before versus 1 Minute after begin of intervention ]Flow-mediated dilation will be measured at rest and during each of the interventions.
- Change in FMC during sympathetic activation [ Time Frame: Change in FMC before versus 1 minute after begin of each intervention ]Change in Flow-mediated constriction induced by each of the interventions.
|Study Start Date:||October 2012|
|Study Completion Date:||March 2014|
|Primary Completion Date:||March 2013 (Final data collection date for primary outcome measure)|
Active Comparator: Myogenic activation
Subjects will undergo endothelial function assessment at rest and, after a 45 minutes pause, 1 minute after begin of myogenic activation
Procedure: Myogenic activation
A pneumatic cuff will be inflated to suprasystolic pressure around both thighs and the subjects will be asked to perform plantar flexion exercises.
Active Comparator: Cold pressure test
Subjects will undergo endothelial function assessment at rest and, after a 45 minutes pause, 1 minute after begin of cold pressure test
Procedure: Cold pressure test
A hand will be placed in ice-cold water.
Active Comparator: mental stress
Subjects will undergo endothelial function assessment at rest and, after a 45 minutes pause, 1 minute after begin of mental stress
Procedure: Mental stress
Subjects will be asked to perform complex mathematic operations at a very fast pace
Active Comparator: Control
Control visit - no intervention performed - subjects will undergo endothelial function measurement twice at a distance of 45 minutes
Other: no intervention
Please refer to this study by its ClinicalTrials.gov identifier: NCT01713374
|University Medical Center Mainz|
|Mainz, Rheinland Pfalz, Germany, 55131|
|Principal Investigator:||Tommaso Gori, MD PhD||University Medical Center Mainz|