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| ID | Type | Description | Link |
|---|---|---|---|
| 2025-A02282-47 | Other Identifier | French Ethics Committee (Comité de Protection des Personnes) |
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Sleep apnoea-hypopnoea syndrome (SAHOS), which causes numerous comorbidities, particularly cardiovascular ones, is widespread worldwide today and incurs significant healthcare costs.
Current research in this field focuses on identifying different phenotypes in affected patients in order to provide more personalised treatment.
One of these phenotypes appears to be linked to instability in ventilatory control due to an increase in loop gain (LG) in these subjects.
However, the pathophysiology of this ventilatory control instability due to increased LG is not fully understood. It is still difficult to determine whether subjects have an intrinsically high LG or if exposure to intermittent hypoxia during OSA promotes an increase in LG.
It has also been demonstrated that OSA causes vascular hyperreactivity by increasing oxidative stress through elevated ROS production. This leads to endothelial dysfunction in response to intermittent hypoxia associated with apnoea. Extracellular vesicles (microvesicles and exosomes) have been shown to play a role in this endothelial response. These extracellular vesicles are essential for intercellular communication in both physiological and pathological situations, such as SAHOS.
Therefore, the objective of this research is to determine whether exposure to intermittent hypoxia and changes in microvesicle phenotype could influence LG, which could lead to new therapeutic advances in the context of SAHOS.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Arm A : ambient air then intermittent hypoxia | Experimental | T1 : Conduct the experiment in ambient air (without hypoxia) for six hours. T2 : Then, after a washout period of at least seven days, conduct the experiment in intermittent hypoxia via the hypoxia chamber for six hours. |
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| Arm B : intermittent hypoxia then ambient air | Experimental | T1 : Conduct an experiment involving intermittent hypoxia in the hypoxia chamber for six hours. T2 : Then, after a washout period of at least seven days, conduct an experiment involving ambient air (without hypoxia). |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Intermittent hypoxia | Procedure | The volunteer will remain at rest in the hypoxic chamber, experiencing intermittent hypoxic conditions cyclically every 6 minutes. During one third of the cycle, they will be exposed to hypoxia in order to reduce SpOâ‚‚ to between 85% and 90%. Then, during two thirds of the cycle, they will receive oxygenation at a rate of 1 L/min (with possible subject-dependent modulations), with the aim of achieving an SpOâ‚‚ of greater than 95%. To make the hypoxia intermittent, the volunteer will also be given a medium-concentration oxygen mask that provides intermittent airflow, controlled by the D-6341 mass flow controller. |
| Measure | Description | Time Frame |
|---|---|---|
| To evaluate the effect of intermittent hypoxia for 6 hours on the evolution of Loop Gain | Loop gain is the product of 'controller gain' (ventilatory responsiveness to COâ‚‚ above eupnoea) and 'plant gain' (the ventilatory increase required for a given reduction in PaCOâ‚‚). Loop gain will be measured before (30 minutes of rest following the participant's arrival) and after (20 minutes before the end of the hypoxia chamber session) the test or control condition (intermittent hypoxia or ambient air). The following ventilatory parameters will be measured using a gas exchange measuring device to calculate loop gain, plant gain and controller gain:
The evaluation criterion will be the difference in the average loop gain value before and after the experimental conditioning (i.e. observation of the change). | through study completion (visit 1 and visit 2), an average of 14 months |
| Measure | Description | Time Frame |
|---|---|---|
| To compare the evolution of controller gain and plant gain between experimental conditions in hypoxia and ambient air | We will assess the change in controller and plant gains by measuring the difference before and after the experimental conditioning of these gains. Our focus will be on the average values of the controller and plant gains, which were measured over spontaneous breathing cycles of 5 to 10 minutes, and assessed before and after the experiment. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Vanessa BIRONNEAU, MD | Contact | 05 49 44 34 49 | +33 | vanessa.bironneau@chu-poitiers.fr |
| Celine ABONNEAU, Project manager | Contact | 05 16 60 42 33 | +33 | celine.abonneau@chu-poitiers.fr |
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| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Poitiers University Hospital | Poitiers | 86000 | France |
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| Normoxia | Procedure | The participant will remain at rest in the hypoxic chamber under normoxic conditions. To prevent the volunteer from becoming aware of the conditions to which they are exposed, an air flow rate of 1 L/min will be used to simulate intermittent oxygenation. |
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| through study completion (visit 1 and visit 2), an average of 14 months |
| To compare the change in the quantity of extracellular vesicles between experimental conditions in hypoxia and ambient air. | The quantity of extracellular vesicles was assessed from blood samples using flow cytometry with specific antibodies. This change is expressed as the difference in the following extracellular vesicle concentrations before and after experimental conditioning:
| through study completion (visit 1 and visit 2), an average of 14 months |
| To assess whether changes in the quantity of extracellular vesicles (and microvesicles) correlate with changes in loop gain, both under experimental conditions in hypoxia and under experimental conditions in ambient air. | We are interested in changes in the quantity of extracellular vesicles, as assessed by the difference in extracellular vesicle concentration before and after the experimental condition. This is measured from blood samples taken. We are interested in the following extracellular vesicles: CD41, CD235a, CD45, CD146, CD66b, CD11b, CD62L, CD62E, CD62P and CD62/platelet annexin V. The change in loop gain will be calculated as for the primary endpoint (the difference in concentration before and after the experimental condition). | through study completion (visit 1 and visit 2), an average of 14 months |
| To compare changes in loop gain between experimental conditions in hypoxia and ambient air, on the one hand in the subgroup of patients with hyperventilation syndrome and on the other hand in the subgroup of patients without hyperventilation syndrome. | The change in loop gain will be defined in the same way as the primary endpoint, i.e. as the difference between the measurements taken before and after the experimental conditioning. Hyperventilation syndrome will be defined as a Nijmegen score of 23 or above at the inclusion visit. | through study completion (visit 1 and visit 2), an average of 14 months |