NCT03986788: GraCer

Cerebral Blood Flow Distribution During Parabolic Flight-induced Microgravity

Status unknown NA Last updated 25 February 2020

What this trial tests

NA trial testing Weightlessness in Weightlessness in 18 participants. Status unknown.

Timeline

1 October 2018

Primary endpoint
30 September 2021

30 September 2021

Quick facts

Lead sponsor	University Hospital, Caen
Phase	NA
Status	Status unknown
Study type	INTERVENTIONAL
Allocation	na
Design	single group
Masking	none
Primary purpose	basic science
Enrollment	18
Start date	1 October 2018
Primary completion	30 September 2021
Estimated completion	30 September 2021
Sites	1 location across France

Drugs / interventions tested

• Weightlessness

Conditions studied

• Weightlessness — all drugs for Weightlessness →
• Cerebral Blood Flow — all drugs for Cerebral Blood Flow →

Sponsor

University Hospital, Caen

Who can join

Adults 18 to 65, any sex, with Weightlessness or Cerebral Blood Flow. Patients with the condition only — healthy volunteers not accepted.

Sponsor's own description

When astronauts return from space flight, they manifest a set of symptoms, the most striking of which is orthostatic intolerance, that is, the inability to stay upright. This orthostatic intolerance is related to cardiovascular adaptation and disappears in a few days, but the prospect of long-term space travel makes this maladaptation a major concern of space agencies, at a time when there is serious consideration to make " land "a ship on Mars.

Previous studies suggest that brain vessel adaptation may contribute to spatial post-flight orthostatic intolerance. The question remains controversial because not all studies are consistent. These studies are all based on the measurement of blood flow in a single artery of the brain (the average cerebral, see cerebral circulation diagram) easily accessible with a Doppler ultrasound machine. Our team has good reason to believe that the adaptation of the cerebral vessels is not carried out in the same way in all the arteries of the brain and that in particular the arteries that irrigate the posterior and inferior parts of the brain are a major determinant. from cerebrovascular adaptation to orthostatism and that orthostatic intolerance is more specifically related to a decrease in blood flow in these arteries. On the other hand our team has shown that the external carotid artery plays, under certain conditions, a buffer role of the sudden variations of perfusion pressure of the brain.

During the weightless phase of parabolic flight, part of the blood from the legs and abdomen "rises" to the thorax and this transfer of fluid induces changes in blood pressure and cardiac output that affect the cerebral circulation. From a cardiovascular point of view, it is the same thing for a seated subject to lie down, but the parabolic flight offers the unique possibility of achieving this transfer in a fraction of a second and thus allowing to study the immediate response of the cerebral circulation. .

Investigators goal is therefore to quantify the changes in blood flow in the posterior and anterior territories of the brain (transcranial ultrasound) as well as in the internal carotid and vertebral (Doppler ultrasound) during changes in blood pressure and cardiac output induced by transfers. liquid resources associated with the transition to weightlessness.

The oxidative stress generated by weightlessness has been identified as a determining factor in cerebrovascular deconditioning associated with orthostatic intolerance. In order to quantify the biochemical markers of this stress, a venous sample will be taken before and just after the parabolic flight.

Publications & conference data

No peer-reviewed publications indexed yet for this trial.