Living in Space
Integral Understanding of life-regulation mechanism from "SPACE"

Cardiovascular Regulatory Mechanism – Programmed Research

1. A01-1
2. A01-2
3. A01-3
4. A02-1
5. A02-2
6. A02-3
7. A02-4
8. A02-5
9. A03-1
10. A03-2
11. A03-3

Research Subject	A02-1 Changes in the Cardiovascular Regulatory Mechanism due to Gravitational Variations and Confinement
Research Group Leader	Kenichi Iwasaki Professor, School of Medicine, Nihon University Website http://www.med.nihon-u.ac.jp/department/spacemed/ (*Japanese)
Research Group Members	Yojiro Ogawa Associate Professor, School of Medicine, Nihon University Ryo Yanagida Research Assistant, School of Medicine, Nihon University Chiharau Takko Research Assistant, School of Medicine, Nihon University Takashi Ohira Researcher, Japan Aerospace Exploration Agency(JAXA)
Research Collaborator(s)	Takahiro Suzuki Professor, School of Medicine, Nihon University Takeshi Maeda Associate Professor, School of Medicine, Nihon University Noriya Hirose Research Assistant, School of Medicine, Nihon University Yuko Kondo Research Assistant, School of Medicine, Nihon University Kaname Ueda Research Assistant, School of Medicine, Nihon University Ari Shinojima Assistant Professor, School of Medicine, Nihon University

Previous studies have revealed that a substantial change occurs in the circulatory regulatory mechanism when a human experiences spaceflight. The circulatory system is separately regulated by a variety of regulatory mechanisms, in cerebral, ocular, coronary, and peripheral circulations; these separate regulatory actions cooperate together to maintain homeostasis as a whole. Changes in Space are complex and affect each mechanism differently. Furthermore, these changes may be induced by several factors, such as exposure to microgravity during a stay in Space, exposure to hypergravity during flights to and from Space, reduced exercise while in Space (decrease in physical activity), and stress due to confinement.

However, isolating one specific factor in an experiment in Space is difficult. For instance, consider gravitational variation. When dealing with a broad range of gravitational variations from microgravity (μG) to the gravity of Earth (1 G) and hypergravity (for example, 2 G), it is not immediately clear what kinds of characteristic features [linear (i.e. first-degree), U-shaped curve, or S-shaped curve] the dose-dependent variation of the circulatory regulatory mechanism would exhibit.

In this Programmed Research, which aims to extend studies in Space and similar special environments toward basic medical sciences, we will conduct experiments isolating three major factors affecting the circulatory regulatory mechanism (gravitational variation, reduced exercise, stress due to confinement, etc.) and assess the changes in the circulatory regulatory mechanism by organ due to each factor. Our objective is to elucidate a comprehensive picture of the changes that occur in the circulatory regulatory mechanism.

More specifically, we will assess the changes in the circulatory regulatory mechanism of subjects in different experiments: (1) varying gravity experiments using a centrifugal artificial gravity generator, (2) bed rest and supplemental exercise application experiments, and (3) stress experiments using JAXA’s confinement experiment facilities. We will further examine how these are related to other changes due to microgravity or stress in biological systems in collaboration and data sharing with other Programmed and Proposed Research groups.