Intraosseous Doppler Ultrasonography to Study Skeletal Physiology: Exploratory Study Before Use in Space Physiology

Summary

Use of intraosseous Doppler ultrasonography to study skeletal physiology ("Echo-Os Study"). Exploratory study before its use in space physiology.

Bones have a complex vascular network providing nutrients and oxygen to bone cells. The physiology of intraosseous blood circulation remains very little known to date, particularly in human. Human bone vascularization studying is very difficult because of a lack of simple tools for functional exploration of bone vascular perfusion. For blood flow studies, ultrasonography is best suited, allowing for dynamic non-invasive measures. Bone has until now been considered to stop ultrasound and therefore prevent any intraosseous measurements. From a physics viewpoint, bones conduct ultrasound waves well, but they are reflected differently compared to soft tissues. A specific analysis of the ultrasound returned by the bone, using specific correction factors, is therefore needed to interpret ultrasound signals, reconstruct an anatomical image, and extract physiological information. The system proposed in this study combines standard conventional low-frequency ultrasound probes with a specific analysis of ultrasound wave reflection. This system makes it possible to reconstruct an anatomical bone image and record the pulsatile signal of intraosseous vascular perfusion. The investigators will use this system to study the vascular reactivity induced by different physiological maneuvers.

This protocol proposes to study the following mechanisms of blood flow regulation at the level of tibia cortical bone: flow-mediated dilation induced by endothelium (with arterial occlusion test), vasoconstriction induced by sympathetic activation (with static handgrip test), and vasoconstriction induced by veno-arteriolar reflex (with venous occlusion test). This is a pilot study in physiology performed with healthy volunteers. This study will verify whether our intraosseous ultrasound system can properly measure physiological responses expected during these maneuvers. This protocol will also establish links between perfusion and bone architecture at tibial level.

Conditions

• Healthy Volunteers

Interventions

DEVICE

Intraosseous ultrasonography at tibia before, during, and after a physiological vascular stimulation (venous occlusions, arterial occlusion, handgrip)

Timing for sub-protocol 1 (performed twice with 2-to-10-day interval): donning in supine position - rest 5 minutes - venous occlusion to 40 mmHg 3 minutes - rest 10 minutes - arterial occlusion to 200mmHg 2 minutes - post-occlusion period 10 minutes - rest 10 minutes - static handgrip 30% Maximum Voluntary Force 3 minutes - recovery 2 minutes and doffing. Timing for sub-protocol 2 (performed once). First, two sequences of intraosseous ultrasonography are performed in 45° head-up tilt position, with 10-minutes rest between sequences: donning and rest 5 minutes - occlusion to 80 mmHg 2 minutes - rest 10 minutes - occlusion to 180 mmHg 2 minutes - rest 10 minutes. During the first sequence, ultrasonography probe is positioned between middle and lower third of tibia for cortical bone measurement; during the second - at distal epiphysis of the tibia for trabecular bone measurement. After ultrasonography, subject is sitting down for 10 minutes for computed tomography.

Sponsors & Collaborators

• University Hospital, Angers

  lead OTHER_GOV

Principal Investigators

• Marc-Antoine CUSTAUD, Professor · University Hospital, Angers

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

20 Years

Max Age

70 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-03-04

Primary Completion

2024-10-17

Completion

2024-10-17

Countries

• France

Study Locations