Simulation of a Mission Aboard the International Space Station by a Long Duration Anti-Orthostatic Bed Confinement at - 6° (90 Days) on Healthy Subjects:1/Perfecting of Preventive Methods (Muscular Exercise and Biphosphonates) and Evaluation of the Effects on the Locomotion and Cardiovascular Systems and on the Lipid and Energy Metabolisms. 2/Pharmacokinetic Assessment: Effects of Position on the Absorption Mechanisms: Pharmacokinetics of Paracetamol Used as Model to Study Oral Absorption in Simulated Weightlessness
试验速览
- 阶段
- 1 期
- 状态
- 已完成
- 入组人数
- 28
- 试验地点
- 2
- 主要终点
- Muscle size and function
研究概览
简要总结
Microgravity during space flight induces physiological changes that affect astronauts' health and performance. Space flight simulations such as prolonged bed rest can mimic some of these changes and provide study conditions that are more accessible than during space flight. The European Space Agency, ESA together with the French national space agency, CNES and the Japanese national space agency, NASDA are performing extensive studies using long duration bed rest.
Previous studies including several long and short term bed rest campaigns have yielded significant medical data on the physiological changes induced by space flight. These data can be used to study the effect of countermeasures, methods helping to prevent these physiological changes.
The long duration bed rest, lasting 3 months undertakes a variety of investigations involving 28 subjects. This study focuses on countermeasures, studying the effect of a bone tissue stabilisation medication and resistive exercises to determine their suitability for use during long duration stays on ISS.
The physiological changes recorded during space flight and bed rest mimic those observed in some diseases and in the aging process. Significant clinical applications are expected as a direct result of this experiment and future equivalent studies.
详细描述
The spaceflights undertaken to date demonstrated that Man can adapt to the conditions existing in space, particularly to weightlessness. However, the space environment and the prevailing micro-gravity induce modifications which may affect the performances of the astronauts. These modifications concern in particular the cardiovascular and hormonal systems, the muscles, the bones, the blood and the immune system. Other problems may occur during long duration flights, such as the problems created by psychological stress due to the confinement, or those resulting from the cosmic rays (radiation).
In view of the fact that space flight opportunities are few, experiences simulating the effects of weightlessness experiences are undertaken on the earth, in order to better understand the adaptation mechanisms, prepare the spaceflights, perfect and evaluate corrective methods (called counter-measures) such as physical exercise or medication, to facilitate the astronauts' return to base. These experiments are also a necessity, in view of the difficulties encountered when carrying out certain experiences during the flights, due to the presence of too few astronauts on board, and to the lack of advanced biomedical devices onboard (scanner, etc.). The most common simulation is that of the anti-orthostatic bed rest (tilted position with the head slightly under the feet at a -6° angle).
Since the current objective is to simulate flights in the International Space Station (3 to 6 months) or possible flights to Mars (500 to 1000 days), it is mandatory to extend the duration of the simulation experiments. This is why three Space Agencies, CNES (France), European Space Agency (ESA, European Union), National Space Development Agency of Japan (NASDA, Japan) decided to join forces and undertake in common such simulation campaigns on ground, to best apprehend the adaptation processes to the constraints of the space environment.
The 2 main objectives of this experiment are:
- to study the physiological changes mechanisms during a ground-based experiment simulating long duration spaceflights,
- to develop and validate preventive methods (countermeasures) using standard tests.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Prevention
- 盲法
- None
入排标准
- 年龄范围
- 25 Years 至 45 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 否
入选标准
- •Healthy male volunteer , citizen of the European Community.
- •Age 25 to 45,
- •Non smokers,
- •No alcohol, no drug dependence and no medical treatment,
- •Height 165 cm to 185 cm,
- •No overweight nor excessive thinness. BMI (weight Kg/ height m2) between 20 and 27,
- •No personal nor family past record of chronic or acute disease which could affect the physiological data and/or create a risk for the subject during the experiment,
- •Subject to be covered by a Social Security system,
- •Free of any engagement during four consecutive months.
排除标准
- •Having given blood (more than 300ml) in a period of three months or less before the start of the experiment,
- •Subject already participating in a clinical research experimentation,
- •Poor tolerance to blood sampling,
- •Past record of orthostatic intolerance,
- •Cardiac rhythm disorders,
- •Allergies,
- •Intensive sport training,
- •Fractures or tendon laceration since less than one year,
- •Chronic back pains,
- •Past records of thrombophlebitis,
- •Presence of metallic implants,
- •Special food diet,
- •Sleep disorders :Lark and owl type,Subject sleeping more than 10 hours or less than 5 hours,
- •Photosensitive epilepsy.
结局指标
主要结局
Muscle size and function
Bone mineral content and structure
Muscle protein composition, muscle fiber type composition andmuscle enzyme content of soleus and vastus lateralis muscles
and subjective rating of back pain
Maximal oxygen consumption.
Cardiovascular oxygen transport (oxygen delivery and oxygen return), requiring measurement of cardiac output, heart rate, arterialized blood gas composition, and arterial oxygen saturation.
Gas exchange kinetics at the onset and offset of exercise, requiring measurement of breath-by-breath ventilation and expired gas composition.
Arterial cardiac chronotropic baroreflex sensitivity and ventricular interdependence.
Ventricular mass and cardiac dimension.
Fluid volume shift
Acetaminophen pharmacokinetic parameters,
Blood volume
Parameters of central hemodynamics
Isokinetic muscle strength (using Cybex)
Sleep assessment by questionnaires and actigraphy
RR interval from an ECG lead signal by an high impedance probe, Systolic (SAP), Diastolic (DAP) and Mean arterial pressure (MAP) by Finapres (or Portapres) andRespiration by a piezoelectric pneumobelt,
24 h profile of spine geometry,flexibility index of spine, activity of lower back muscles,
Calcium metabolism and hormonal control
Heart rate variability and post-ganglionic sympathetic nerve activity.
Muscle architecture, including angle of pennation, fibre length, muscle thickness and muscle cross-sectional area
Energetics and biomechanics of walking and running
Plasma concentrations of arginin vasopressin, atrial natriuretic peptide, renin, endothelin, cyclic GMP and catecholamines. Urine concentrations of catecholamines, arginin vasopressin and cyclic GMP Blood concentration of nitric oxide.
Total energy expenditure, Lipid metabolism, body composition, water turnover and the formation of metabolic water.
Parameters of vascular peripheral hemodynamics
次要结局
未报告次要终点