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Overview

Center for Space Radiation Research (CSRR)

Principal Investigator:
Marjan Boerma, Ph.D.

Organization:
University of Arkansas for Medical Sciences

When astronauts travel beyond low-Earth orbit (LEO), they will be exposed to galactic cosmic rays and will also be at risk of exposure to bursts of proton radiation due to largely unpredictable solar particle events. (SPEs). While the health problems from an SPE can be immediate, exposure to heavy ions (galactic cosmic rays) may cause long-term health risks. For instance, the results of recent epidemiological studies on Earth-based radiation exposures suggest that the heart and vasculature may be more sensitive to radiation than previously thought and may be at risk for late degenerative effects.

The Center for Space Radiation Research (CSRR) is comprised of teams from four institutions that work closely together to assess both the acute and late risks of low-dose proton and heavy ion exposures, and identify safe countermeasures that may protect astronauts against radiation effects. The researchers will use animal models to conduct the studies.

NASA Taskbook Entry

Technical Summary

The Center for Space Radiation Research (CSRR) comprises teams of investigators from the University of Arkansas for Medical Sciences (UAMS), Loma Linda University, Georgetown University, and the University of Arizona to address acute and late effects of exposure to space radiation. The CSRR uses multiple animal models to examine the acute effects of low-dose SPE-like protons and degenerative tissue effects of exposure to low-dose protons and heavy ions.

Acute effects are examined at doses below 0.5 Gy, with a focus on the hematopoietic system, skin, microvasculature, and adaptive immune response. Studies include exposure to hind limb suspension to model fluid shifts due to microgravity.

Cardiovascular effects are assessed by exposing animals to protons and heavy ions at doses up to 1 Gy. Animals are observed up to 9 months after irradiation, and in vivo longitudinal analysis of cardiac function are performed with non-invasive high-resolution cardiac ultrasound. Since space travel has been associated with degradation of vision, but changes in topology and function of the retinal microvasculature have not been well defined, the structure of the retinal microvasculature is assessed with in vivo retinal microscopy during post-radiation follow-up of the animals. Functional and structural tissue responses are integrated with proteomic, metabolomic, and epigenetic signatures in plasma and tissue samples to identify biomarkers and assess novel molecular pathways in tissue injury. In addition, pertinent in vitro experiments with protons and heavy charged particles in three-dimensional models of the endothelial microvascular network are used to obtain additional insight in molecular mechanisms. Lastly, work focuses on γ-tocotrienol, a safe dietary antioxidant and the strongest natural product radiation protector yet discovered, as a potential countermeasure against the effects of space radiation.

Altogether, these studies use innovative methods to characterize acute and late effects of exposure to space radiation, and will aid in the development of countermeasures to make human space travel safer.

Earth Applications

It is well known that exposure to ionizing radiation can result in various types of adverse biological effects. The countermeasures being developed as part of this research program have significance for all individuals exposed to ionizing radiation on Earth as well as in space. The countermeasures shown to protect against radiation-induced biological effects from space radiation may be equally useful for protection against radiation-induced biological effects on Earth.

The work of the CSRR is particularly germane to Earth applications, given that some of the world’s leading cancer centers are now using particles such as protons or carbon ions to treat patients.

This project's funding ended in 2015