BRAHMS: Bed Rest And HypoMetabolism Study

Centre National d'Etudes Spatiales

Status

Enrolling

Conditions

Microgravity

Caloric Restriction

Treatments

Other: head down bedrest and caloric restriction

Study type

Interventional

Funder types

Other

Identifiers

NCT07499167

25-369

Details and patient eligibility

About

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:

Cardiovascular, muscular, neuro-vestibular and neuropsychological functional performance
The onset of clinical symptoms and biological changes

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.

Enrollment

10 estimated patients

Sex

Male

Ages

20 to 40 years old

Volunteers

Accepts Healthy Volunteers

Inclusion criteria

Healthy male volunteers (see below the description of medical tests and laboratory analysis performed at the selection visit)
Certified as healthy by a comprehensive clinical assessment (detailed medical history and complete physical examination): in particular, free from any known chronic disease or any acute mood or eating disorder, infectious disease or cardiovascular, metabolic, neurological, ENT (especially orthostatic hypotension and vestibular disorders), orthopedic or musculoskeletal disorders.
20 to 40 years old
165 to 185 cm
Body Mass Index between 20 and 26 kg.m-2
Stable body weight in the past 3 months (less than 4% change)
Fat Mass Index (FMI), defined as (bodyfat weigh in kg)/(height in m)2: between 3 and 6 kg.m-2, measured by whole-body DEXA
Triglyceride level under 1.7 mmol.L-1
Normal bone mass density at left hip and lumbar spine: T-score>-1.5, measured by DEXA
VO2peak/VO2max between 35 and 55 mL.min-1.kg-1
Non-smokers
No alcohol or drug dependence, no medical treatment on a regular basis
Affiliated to a Social Security system and, for non-French resident, holding a European Health Insurance Card (EHIC) or a Global Health Insurance Card (GHIC).
Free of any engagement during the study
Who agreed to take part in the study and signed the informed consent

Exclusion criteria

Any history or presence of clinically relevant chronic disease; any acute infectious disease. Particularly (but not limited to):
Symptomatic orthostatic hypotension whatever the decrease in blood pressure, or asymptomatic postural hypotension defined by a decrease in SBP equal to or greater than 20 mmHg within 3 minutes when changing from the supine to the standing position
Personal or family history of thrombosis, genetic mutation for factor V or prothrombin gene
Cardiac arrhythmia
Hypertension
Auto-immune diseases or Raynaud's syndrome
History or symptoms of sleep apnea
Chronic back pains,
Vertebral fracture, scoliosis, or herniated disc,
Color-blindness,
Self-reported hearing problems or binocular visual acuity under 6/10 after correction
Vestibular disorders
Drug addiction
History of migraines,
History of hiatus hernia or gastro-esophageal reflux,
History of thyroid dysfunction or diabetes
History of head trauma,
History of neurological diseases (e.g. epilepsy)
History of genetic muscle and bone diseases of any kind
Significant history of allergies
Significant abnormality in blood tests
Positive serology for hepatitis A, hepatitis B, hepatitis C or AIDS (HIV) virus
Mood and Eating disorder (current or past), screened with the Hospital Anxiety Depression Scale (HADS), SCOFF (Sick, Control, One, Fat, Food) and the Eating Disorder Examination Questionnaire (EDE-Q)
Antibiotics exposure 2 months prior to the study
Major lifestyle changes (e.g. significant weight/body changes, diet or exercises regimen) 6 months prior to the study
Specific diet (e.g vegan, carnivore, intermittent fasting, dietary supplements consumption)
History of hypocaloric diet, judged as significant by the investigator
Subject who, in the judgment of the investigator, is likely to be non-compliant during the study, or unable to cooperate because of a language problem or poor mental development,
Subject in the exclusion period of another clinical research,
Subject who received 6000 Euros or more within 12 months for being a research subject,
Poor tolerance to blood sampling,
Subject who cannot be contacted in case of emergency,
Contraindications for MRI: claustrophobia, presence of osteosynthesis material or metal implants,
Blood donation of more than 7 ml/kg in the 8 weeks prior to the start of the study,
Vulnerable people according to law "Code de la Santé Publique" (L1121-5 to L1121-8):
Pregnant or nursing women (urine pregnancy test for women of childbearing potential)
People deprived of their liberty by an administrative or judicial decision
People under involuntary psychiatric care
People admitted in a health or social establishment for purposes other than research
Minors
Adults subject to legal protection (subject under guardianship or trusteeship) or unable to express their consent