Development of an adverse outcome pathway relevant to health outcomes from space travel

Long-duration space flight can cause increased health risks to astronauts. This is partly due to a multitude of stressors that can significantly impact human physiology in a hostile space environment.

Stressors can include microgravity, space radiation and altered atmospheric gas. Space radiation is particularly detrimental, as it is difficult to shield from it.

These stressors may interact to damage biomolecules, cells, tissues and organs, leading to short- and long-term health effects that can impact various organ systems.

Solar particle radiation and, to a lesser extent, galactic cosmic rays are the most abundant sources of space radiation, which consists primarily of heavy ions, high energy protons and secondary particles.

This project aims to determine the adverse outcome pathways (AOPs) that are relevant to space travel to facilitate risk assessment of potential health effects from exposures to these stressors. In particular, the project will develop AOPs relevant to cardiovascular effects, bone loss, ocular disorders and cognitive/behaviour effects, which are most applicable to space travel.

The project is a collaboration between the Canadian Space Agency, NASA and Health Canada.

About adverse outcome pathways

In 2012, the Organisation for Economic Co-operation and Development launched the Adverse Outcome Pathways framework to improve efficiency for chemical safety assessment. An AOP is a detailed model that illustrates the sequence of molecular and chemical events required to produce a toxic effect when an organism is exposed to a substance. AOPs begin with a molecular initiating event and are empirically supported through evidence using the Bradford Hill criteria. The approach is gaining attention in the radiation community for its usefulness in organizing data and identifying knowledge gaps to help direct future research.