Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| Name | Class |
|---|---|
| MEDES Institut de Médecine et de Physiologie Spatiales, Toulouse | UNKNOWN |
Not provided
Not provided
Not provided
Not provided
The goal of this single arm, interventional monocentric clinical trial is to investigate the physiological effects of a combination of head-down bedrest and caloric restriction on the human body. A set of measurements will assess the changes in the musculoskeletal, cardiovascular, hematological, immune, neurological, cognitive and metabolic systems, in 10 healthy male volunteers.
The main question it aims to answer is: what are the physiological responses to fasting in a microgravity environment?
In an exploratory study such as this one, where many physiological systems are explored, it is difficult to select a single important endpoint. However, given the known effect of both caloric restriction and head-down bedrest on muscle loss, and its critical importance for the success of space missions, lean body mass, as assessed by DEXA, was chosen as the primary endpoint.
The secondary endpoints are:
Participants will be exposed to a microgravity analog model (head down bed rest) and controled caloric restriction environment for 10 days, multiple physiological assessments will be performed during this period. Followed by a rehab period before leaving the study.
Not provided
Not provided
Not provided
Not provided
Not provided
| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Caloric restriction | Experimental | head down bedrest and caloric restriction (250 kcal/day) |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| head down bedrest and caloric restriction | Other | the intervention is 10 days of head down bedrest (-6°) and controlled and progressive caloric restriction, then controlled and progressive refeeding |
| Measure | Description | Time Frame |
|---|---|---|
| Lean Body Mass | Lean Body Mass assessed by dual energy x-ray absorptiometry (DEXA) | At baseline, during the ten days of intervention and until 90 days after the end of the intervention |
| Measure | Description | Time Frame |
|---|---|---|
| Change in body fluid compartments by bioelectrical impedance analysis | Extracellular, intracellular and total body water (L) will be estimated by bioimpedance | At baseline, during the ten days of intervention and until 90 days after the end of the intervention |
| Change in whole-body Magnetic Resonance Imaging (MRI) |
Not provided
Inclusion Criteria:
Exclusion Criteria:
biological males
Not provided
Not provided
Not provided
Not provided
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Medes - Imps | Toulouse | Medes-imps | 31400 | France |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
| ID | Term |
|---|---|
| D031204 | Caloric Restriction |
| ID | Term |
|---|---|
| D004035 | Diet Therapy |
| D044623 | Nutrition Therapy |
| D013812 | Therapeutics |
| D002149 | Energy Intake |
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Not provided
Change in MRI-measured whole-body Lean mass (kg) and Fat mass (kg) will be estimated |
| At baseline and at day 9 of intervention period |
| Change in mood | Change in mood is assessed using the Profile of Mood States (POMS) questionnaire. POMS questionnaire gives 6 measures of mood: Tension/anxiety, Depression, Anger/hostility Dynamism, Fatigue, Confusion A Total Mood Disturbance (TMD) score is calculated by summing the totals for the negative subscales (tension, depression, fatigue, confusion, anger) and then subtracting the totals for the positive subscale (vigor /esteem-related affect). | At baseline, during the ten days of intervention and until 4 days after the end of the intervention |
| Assessment of movements by volunteers | Actigraphs attached to wristbands placed on the non-dominant wrist and ankle of each volunteer | At baseline, during the ten days of the intervention and until 4 days after the end of the intervention |
| Change in cardiovascular deconditioning and orthostatic tolerance (stand test) | This test continuously measures heart rate (bpm) via a Finapres device while subjects sit for 5 minutes, then stand for 10 minutes and then sit again for 5 minutes | At baseline and 1 day after the end of intervention period |
| Changes in orthostatic tolerance | Orthostatic tolerance will be assessed during a tilt test combined with Lower Body Negative Pressure test (LBNP test) | At baseline and 1 day after the end of intervention period |
| Changes in peak aerobic power (VO2max test) | Exercise capacity wil be assessed by graded cycling on sitting ergometer until exhaustion | At baseline and 4 days after the end of intervention period |
| Changes in plasma volume | Plasma volume (L) will be assessed by the Dill & Costill method | At baseline, during the ten days of the intervention and until 4 days after the end of the intervention |
| Change in long term blood pressure | This test continuously measures Blood Pressure during 24 hours with the SOMNOTouch device. | At baseline, during the 10 days of the intervention, and 4 days after the end of the intervention |
| Change in macrocirculation | Macrocirculation will be assessed using standard ultrasound measurements at the carotid and femoral levels (arteries and veins). | At baseline, during the 10 days of the intervention, and at 3 days after the end of the intervention |
| Change in endothelial function | The tests consists in the measurement of the variations of the brachial artery diameter as a response to shear stress. | At baseline, during the 10 days of the intervention, and 3 days after the end of the intervention |
| Myofiber atrophy evaluation | Biopsy sampling from m. vastus lateralis will be performed to measure structure and function of muscle fibers. | At baseline and at day 9 of intervention |
| Changes in jump performance | Jump performance will be assessed on a platform and height of the jump will be evaluated | At baseline and 1 day after the end of the intervention |
| Change in protein metabolism | Labeled tracers (¹³C leucine for oxidation, ¹⁵N-phenylalanine for degradation, ²H₅-phenylalanine for synthesis monitoring and NaH13CO3 for quantification of amin acid oxidation) will be infused to the volunteers, and blood, urine, muscle and breath samples will be collected. | At baseline and at day 9 of the intervention |
| Change in muscle strength | Muscle strength will be assessed via dynamometry | At baseline and 2 days after the end of the intervention |
| Change in bone biological marker | Measuring bone-specific Alkaline Phosphatase (bAP) in blood | At baseline, during the ten days of intervention and until 90 days after the end of the intervention |
| Changes in bone density (by High Resolution Peripheral Computed Tomography (HR-pQCT)) | Bone density (g/cm2) is measured at tibia and radius level with HR-pQCT. | At baseline and until 90 days after the end of the intervention |
| Changes in Resting Metabolic Rate (RMR) | RMR will be measured by indirect calorimetry technique | At baseline, during the ten days of intervention and until 90 days after the end of the intervention |
| Change in nitrogen balance | Nitrogen balance is a measure of nitrogen input minus nitrogen output. Nitrogen intake is calculated with a nutrition software. Protein oxidation measured in the 24-Hour urine collection estimates nitrogen output. | At baseline, during the ten days of intervention and at 90 days after the end of the intervention |
| Change in metabolic flexibility (Oral Glucose Tolerance Test (OGTT)) | Metabolic flexibility will be measured during OGTT to assess the ability of the body to adjust energy substates' availability. | At baseline and 4 days after the end of the intervention. |
| Change in glucose homeostasis | Continuous measurement of interstitial glucose concentration by Dexcom sensor | From baseline to day 5 after the end of the intervention |
| Change in energy expenditure of tissues and organs (by PET-scan) | Regional mapping of metabolic activity by dynamic PET-scan with ¹⁸F-fluorodeoxyglucose | At baseline and at day 7 of the intervention period |
| Metabolic change in adipose tissue | Histology, cell culture, adipocyte size distribution and whole adipose tissue transcriptome, proteome, lipidome and metabolome on adipose tissue biopsy | At baseline and at day 9 of the intervention |
| Change in gut microbiota | Gut microbiome, metabolome and proteome will be measured in stool samples | At baseline, during the ten days of the intervention and 4 days after the end of the intervention period |
| Modification of self perceived hunger | Questionnaires about self-perceived hunger will be delivered before and after breakfast, lunch, snack, and dinner, or at the equivalent times on the fasting days. The questionnaire consists of a Visual Analogue Scale on which the volunteer must indicate their level of hunger (from 'not at all' to 'extremely') | At baseline, during the ten days of the intervention and until 4 days after the end of the intervention period |
| Change in energy requirements | Change in energy requirements using water labeled with a stable oxygen isotope (H218O) | At baseline and at day 9 of the intervention period |
| Change in motor function (Sit-to-stand test) | Sit-to-stand test : volunteer will be requested to rise as fast as possible from a chair without using hands and stand for 10s. The following parameter will be measured : Settling time after standing. | At baseline and 1 day after the end of the intervention period |
| Change in standing balance | This test assesses standing balance on a platform covered with 12-cm thick medium density foam. | At baseline and 1 day after the end of the intervention period |
| Change in vestibular health | Battery of tests will be used to asses vestibular health: recovery from fall, path integration, distance perception, perception of self-rotation, how long 1', Posner task, antisaccade task | At baseline and 1 day after the end of the intervention period |
| Change in cognitive state | This test monitor changes in the subject's emotional state and executive function by evaluatingpsychotechnical tasks on a laptop (the neurosensorybox) with physiological sensors (SOMNO HD system). | At baseline, during the ten days of the intervention period and at day 5 after the end of the intervention |
| Salivary cortisol evolution | To characterize stress level, morning and evening salivary cortisol (ng/ml) will be assessed | At baseline, at day 1, 3 & 10 of intervention period, and day 4 after the end of the intervention |
| Change in memory performance | Subjects are exposed to a series of images that will have to be remembered. After a delay of 1 hour or 24 hours they will be questioned on a series of images presented under the same conditions and they will have to indicate in a grid whether these images are known or new | At baseline, during the ten days of the intervention period, and until 3 days after the end of the intervention |
| Change in the internal representation of 3D space | This tests consist in a rhythmic point-to-point hand movements in virtual reality. | At baseline, during the ten days of the intervention period, and until 3 days after the end of the intervention |
| Change in gastro-brain interaction | Assessment of the correlation between gastric electrical activity (measured via Electrogastrography) and neural oscillatory responses (measured via Electroencephalography) during a cognitive task | At baseline, during the ten days of the intervention period, and until 4 days after the end of the intervention |
| Change in motor function (Walk and turn test) | Walk and turn test : volunteer will be instructed to walk as quickly as possible straight ahead toward a cone walk around it and return to the chair. Completion time per walk-and-turn trial will be measured. | At baseline and 1 day after the end of the intervention period |
| Change in motor function (Tandem Walk) | Tandem walk : Volunteer will walk 10 heel-to-toe steps with their arms folded across their chests and their eyes closed (3 trials) followed by one trial with their eyes open. Percentage of correct steps will be measured. | At baseline and 1 day after the end of the intervention period |
| D004032 |
| Diet |
| D009747 | Nutritional Physiological Phenomena |
| D000066888 | Diet, Food, and Nutrition |
| D010829 | Physiological Phenomena |